Programs & Examples On #Xt

XT is an implementation in Java of XSLT, created by James Clark.

PHP array value passes to next row

Change the checkboxes so that the name includes the index inside the brackets:

<input type="checkbox" class="checkbox_veh" id="checkbox_addveh<?php echo $i; ?>" <?php if ($vehicle_feature[$i]->check) echo "checked"; ?> name="feature[<?php echo $i; ?>]" value="<?php echo $vehicle_feature[$i]->id; ?>"> 

The checkboxes that aren't checked are never submitted. The boxes that are checked get submitted, but they get numbered consecutively from 0, and won't have the same indexes as the other corresponding input fields.

Uninitialized Constant MessagesController

Your model is @Messages, change it to @message.

To change it like you should use migration:

def change   rename_table :old_table_name, :new_table_name end 

Of course do not create that file by hand but use rails generator:

rails g migration ChangeMessagesToMessage 

That will generate new file with proper timestamp in name in 'db dir. Then run:

rake db:migrate 

And your app should be fine since then.

How to implement a simple scenario the OO way

The approach I would take is: when reading the chapters from the database, instead of a collection of chapters, use a collection of books. This will have your chapters organised into books and you'll be able to use information from both classes to present the information to the user (you can even present it in a hierarchical way easily when using this approach).

Embed ruby within URL : Middleman Blog

<%= link_to "http://www.facebook.com/sharer.php?u=" + article_url(article, :text => article.title), :class => "btn btn-primary" do %>   <i class="fa fa-facebook">     Facebook Share    </i> <%end%> 

I am assuming that current_article_url is http://0.0.0.0:4567/link_to_title

Method Call Chaining; returning a pointer vs a reference?

The difference between pointers and references is quite simple: a pointer can be null, a reference can not.

Examine your API, if it makes sense for null to be able to be returned, possibly to indicate an error, use a pointer, otherwise use a reference. If you do use a pointer, you should add checks to see if it's null (and such checks may slow down your code).

Here it looks like references are more appropriate.

How to use a global array in C#?

Your class shoud look something like this:

class Something {     int[] array; //global array, replace type of course     void function1() {        array = new int[10]; //let say you declare it here that will be 10 integers in size     }     void function2() {        array[0] = 12; //assing value at index 0 to 12.     } } 

That way you array will be accessible in both functions. However, you must be careful with global stuff, as you can quickly overwrite something.

Two constructors

Let's, just as example:

public class Test {     public Test() {         System.out.println("NO ARGS");     }      public Test(String s) {         this();         System.out.println("1 ARG");     }      public static void main(String args[])     {         Test t = new Test("s");     } } 

It will print

>>> NO ARGS >>> 1 ARG 

The correct way to call the constructor is by:

this(); 

Is there a way to view two blocks of code from the same file simultaneously in Sublime Text?

In the nav go View => Layout => Columns:2 (alt+shift+2) and open your file again in the other pane (i.e. click the other pane and use ctrl+p filename.py)

It appears you can also reopen the file using the command File -> New View into File which will open the current file in a new tab

How to correctly write async method?

You are calling DoDownloadAsync() but you don't wait it. So your program going to the next line. But there is another problem, Async methods should return Task or Task<T>, if you return nothing and you want your method will be run asyncronously you should define your method like this:

private static async Task DoDownloadAsync()     {         WebClient w = new WebClient();          string txt = await w.DownloadStringTaskAsync("http://www.google.com/");         Debug.WriteLine(txt);     } 

And in Main method you can't await for DoDownloadAsync, because you can't use await keyword in non-async function, and you can't make Main async. So consider this:

var result = DoDownloadAsync();  Debug.WriteLine("DoDownload done"); result.Wait(); 

Titlecase all entries into a form_for text field

You don't want to take care of normalizing your data in a view - what if the user changes the data that gets submitted? Instead you could take care of it in the model using the before_save (or the before_validation) callback. Here's an example of the relevant code for a model like yours:

class Place < ActiveRecord::Base   before_save do |place|     place.city = place.city.downcase.titleize     place.country = place.country.downcase.titleize   end end 

You can also check out the Ruby on Rails guide for more info.


To answer you question more directly, something like this would work:

<%= f.text_field :city, :value => (f.object.city ? f.object.city.titlecase : '') %>   

This just means if f.object.city exists, display the titlecase version of it, and if it doesn't display a blank string.

String index out of range: 4

You are using the wrong iteration counter, replace inp.charAt(i) with inp.charAt(j).

Keep placeholder text in UITextField on input in IOS

Instead of using the placeholder text, you'll want to set the actual text property of the field to MM/YYYY, set the delegate of the text field and listen for this method:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {     // update the text of the label } 

Inside that method, you can figure out what the user has typed as they type, which will allow you to update the label accordingly.

AngularJs directive not updating another directive's scope

Just wondering why you are using 2 directives?

It seems like, in this case it would be more straightforward to have a controller as the parent - handle adding the data from your service to its $scope, and pass the model you need from there into your warrantyDirective.

Or for that matter, you could use 0 directives to achieve the same result. (ie. move all functionality out of the separate directives and into a single controller).

It doesn't look like you're doing any explicit DOM transformation here, so in this case, perhaps using 2 directives is overcomplicating things.

Alternatively, have a look at the Angular documentation for directives: http://docs.angularjs.org/guide/directive The very last example at the bottom of the page explains how to wire up dependent directives.

My eclipse won't open, i download the bundle pack it keeps saying error log

Make sure you have the prerequisite, a JVM (http://wiki.eclipse.org/Eclipse/Installation#Install_a_JVM) installed.

This will be a JRE and JDK package.

There are a number of sources which includes: http://www.oracle.com/technetwork/java/javase/downloads/index.html.

grep's at sign caught as whitespace

No -P needed; -E is sufficient:

grep -E '(^|\s)abc(\s|$)' 

or even without -E:

grep '\(^\|\s\)abc\(\s\|$\)' 

Gradle - Move a folder from ABC to XYZ

Your task declaration is incorrectly combining the Copy task type and project.copy method, resulting in a task that has nothing to copy and thus never runs. Besides, Copy isn't the right choice for renaming a directory. There is no Gradle API for renaming, but a bit of Groovy code (leveraging Java's File API) will do. Assuming Project1 is the project directory:

task renABCToXYZ {     doLast {         file("ABC").renameTo(file("XYZ"))     } } 

Looking at the bigger picture, it's probably better to add the renaming logic (i.e. the doLast task action) to the task that produces ABC.

C# - insert values from file into two arrays

var Text = File.ReadAllLines("Path"); foreach (var i in Text) {    var SplitText = i.Split().Where(x=> x.Lenght>1).ToList();    //@Array1 add SplitText[0]    //@Array2 add SpliteText[1]   }  

Comparing a variable with a string python not working when redirecting from bash script

When you read() the file, you may get a newline character '\n' in your string. Try either

if UserInput.strip() == 'List contents': 

or

if 'List contents' in UserInput: 

Also note that your second file open could also use with:

with open('/Users/.../USER_INPUT.txt', 'w+') as UserInputFile:     if UserInput.strip() == 'List contents': # or if s in f:         UserInputFile.write("ls")     else:         print "Didn't work" 

getting " (1) no such column: _id10 " error

I think you missed a equal sign at:

Cursor c = ourDatabase.query(DATABASE_TABLE, column, KEY_ROWID + "" + l, null, null, null, null);  

Change to:

Cursor c = ourDatabase.query(DATABASE_TABLE, column, KEY_ROWID + " = " + l, null, null, null, null); 

Xml Parsing in C#

First add an Enrty and Category class:

public class Entry {     public string Id { get; set; }     public string Title { get; set; }     public string Updated { get; set; }     public string Summary { get; set; }     public string GPoint { get; set; }     public string GElev { get; set; }     public List<string> Categories { get; set; } }  public class Category {     public string Label { get; set; }     public string Term { get; set; } } 

Then use LINQ to XML

XDocument xDoc = XDocument.Load("path");          List<Entry> entries = (from x in xDoc.Descendants("entry")             select new Entry()             {                 Id = (string) x.Element("id"),                 Title = (string)x.Element("title"),                 Updated = (string)x.Element("updated"),                 Summary = (string)x.Element("summary"),                 GPoint = (string)x.Element("georss:point"),                 GElev = (string)x.Element("georss:elev"),                 Categories = (from c in x.Elements("category")                                   select new Category                                   {                                       Label = (string)c.Attribute("label"),                                       Term = (string)c.Attribute("term")                                   }).ToList();             }).ToList(); 

Instantiating a generic type

No, and the fact that you want to seems like a bad idea. Do you really need a default constructor like this?

How to get parameter value for date/time column from empty MaskedTextBox

You're storing the .Text properties of the textboxes directly into the database, this doesn't work. The .Text properties are Strings (i.e. simple text) and not typed as DateTime instances. Do the conversion first, then it will work.

Do this for each date parameter:

Dim bookIssueDate As DateTime = DateTime.ParseExact( txtBookDateIssue.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture ) cmd.Parameters.Add( New OleDbParameter("@Date_Issue", bookIssueDate ) ) 

Note that this code will crash/fail if a user enters an invalid date, e.g. "64/48/9999", I suggest using DateTime.TryParse or DateTime.TryParseExact, but implementing that is an exercise for the reader.

How to create a showdown.js markdown extension

In your last block you have a comma after 'lang', followed immediately with a function. This is not valid json.

EDIT

It appears that the readme was incorrect. I had to to pass an array with the string 'twitter'.

var converter = new Showdown.converter({extensions: ['twitter']}); converter.makeHtml('whatever @meandave2020'); // output "<p>whatever <a href="http://twitter.com/meandave2020">@meandave2020</a></p>" 

I submitted a pull request to update this.

Difference between opening a file in binary vs text

The link you gave does actually describe the differences, but it's buried at the bottom of the page:

http://www.cplusplus.com/reference/cstdio/fopen/

Text files are files containing sequences of lines of text. Depending on the environment where the application runs, some special character conversion may occur in input/output operations in text mode to adapt them to a system-specific text file format. Although on some environments no conversions occur and both text files and binary files are treated the same way, using the appropriate mode improves portability.

The conversion could be to normalize \r\n to \n (or vice-versa), or maybe ignoring characters beyond 0x7F (a-la 'text mode' in FTP). Personally I'd open everything in binary-mode and use a good text-encoding library for dealing with text.

Parse error: syntax error, unexpected [

Are you using php 5.4 on your local? the render line is using the new way of initializing arrays. Try replacing ["title" => "Welcome "] with array("title" => "Welcome ")

Please help me convert this script to a simple image slider

Problems only surface when I am I trying to give the first loaded content an active state

Does this mean that you want to add a class to the first button?

$('.o-links').click(function(e) {   // ... }).first().addClass('O_Nav_Current'); 

instead of using IDs for the slider's items and resetting html contents you can use classes and indexes:

CSS:

.image-area {     width: 100%;     height: auto;     display: none; }  .image-area:first-of-type {     display: block; } 

JavaScript:

var $slides = $('.image-area'),     $btns = $('a.o-links');  $btns.on('click', function (e) {     var i = $btns.removeClass('O_Nav_Current').index(this);     $(this).addClass('O_Nav_Current');      $slides.filter(':visible').fadeOut(1000, function () {         $slides.eq(i).fadeIn(1000);     });      e.preventDefault();  }).first().addClass('O_Nav_Current'); 

http://jsfiddle.net/RmF57/

java doesn't run if structure inside of onclick listener

both your conditions are the same:

if(s < f) {     calc = f - s;     n = s; }else if(f > s){     calc =  s - f;     n = f;  } 

so

if(s < f)   

and

}else if(f > s){ 

are the same

change to

}else if(f < s){ 

Autoresize View When SubViews are Added

Yes, it is because you are using auto layout. Setting the view frame and resizing mask will not work.

You should read Working with Auto Layout Programmatically and Visual Format Language.

You will need to get the current constraints, add the text field, adjust the contraints for the text field, then add the correct constraints on the text field.

Highlight Anchor Links when user manually scrolls?

You can use Jquery's on method and listen for the scroll event.

Generic XSLT Search and Replace template

Here's one way in XSLT 2

<?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">   <xsl:template match="@*|node()">     <xsl:copy>       <xsl:apply-templates select="@*|node()"/>     </xsl:copy>   </xsl:template>   <xsl:template match="text()">     <xsl:value-of select="translate(.,'&quot;','''')"/>   </xsl:template> </xsl:stylesheet> 

Doing it in XSLT1 is a little more problematic as it's hard to get a literal containing a single apostrophe, so you have to resort to a variable:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">   <xsl:template match="@*|node()">     <xsl:copy>       <xsl:apply-templates select="@*|node()"/>     </xsl:copy>   </xsl:template>   <xsl:variable name="apos">'</xsl:variable>   <xsl:template match="text()">     <xsl:value-of select="translate(.,'&quot;',$apos)"/>   </xsl:template> </xsl:stylesheet> 

Are all Spring Framework Java Configuration injection examples buggy?

In your test, you are comparing the two TestParent beans, not the single TestedChild bean.

Also, Spring proxies your @Configuration class so that when you call one of the @Bean annotated methods, it caches the result and always returns the same object on future calls.

See here:

Calling another method java GUI

I'm not sure what you're trying to do, but here's something to consider: c(); won't do anything. c is an instance of the class checkbox and not a method to be called. So consider this:

public class FirstWindow extends JFrame {      public FirstWindow() {         checkbox c = new checkbox();         c.yourMethod(yourParameters); // call the method you made in checkbox     } }  public class checkbox extends JFrame {      public checkbox(yourParameters) {          // this is the constructor method used to initialize instance variables     }      public void yourMethod() // doesn't have to be void     {         // put your code here     } } 

Summing radio input values

Your javascript is executed before the HTML is generated, so it doesn't "see" the ungenerated INPUT elements. For jQuery, you would either stick the Javascript at the end of the HTML or wrap it like this:

<script type="text/javascript">   $(function() { //jQuery trick to say after all the HTML is parsed.     $("input[type=radio]").click(function() {       var total = 0;       $("input[type=radio]:checked").each(function() {         total += parseFloat($(this).val());       });        $("#totalSum").val(total);     });   }); </script> 

EDIT: This code works for me

<!DOCTYPE html> <html> <head> <meta charset="utf-8"> </head> <body>   <strong>Choose a base package:</strong>   <input id="item_0" type="radio" name="pkg" value="1942" />Base Package 1 - $1942   <input id="item_1" type="radio" name="pkg" value="2313" />Base Package 2 - $2313   <input id="item_2" type="radio" name="pkg" value="2829" />Base Package 3 - $2829   <strong>Choose an add on:</strong>   <input id="item_10" type="radio" name="ext" value="0" />No add-on - +$0   <input id="item_12" type="radio" name="ext" value="2146" />Add-on 1 - (+$2146)   <input id="item_13" type="radio" name="ext" value="2455" />Add-on 2 - (+$2455)   <input id="item_14" type="radio" name="ext" value="2764" />Add-on 3 - (+$2764)   <input id="item_15" type="radio" name="ext" value="3073" />Add-on 4 - (+$3073)   <input id="item_16" type="radio" name="ext" value="3382" />Add-on 5 - (+$3382)   <input id="item_17" type="radio" name="ext" value="3691" />Add-on 6 - (+$3691)   <strong>Your total is:</strong>   <input id="totalSum" type="text" name="totalSum" readonly="readonly" size="5" value="" />   <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>   <script type="text/javascript">       $("input[type=radio]").click(function() {         var total = 0;         $("input[type=radio]:checked").each(function() {           total += parseFloat($(this).val());         });          $("#totalSum").val(total);       });     </script> </body> </html> 

Cannot retrieve string(s) from preferences (settings)

All your exercise conditionals are separate and the else is only tied to the last if statement. Use else if to bind them all together in the way I believe you intend.

strange error in my Animation Drawable

Looks like whatever is in your Animation Drawable definition is too much memory to decode and sequence. The idea is that it loads up all the items and make them in an array and swaps them in and out of the scene according to the timing specified for each frame.

If this all can't fit into memory, it's probably better to either do this on your own with some sort of handler or better yet just encode a movie with the specified frames at the corresponding images and play the animation through a video codec.

Two Page Login with Spring Security 3.2.x

There should be three pages here:

  1. Initial login page with a form that asks for your username, but not your password.
  2. You didn't mention this one, but I'd check whether the client computer is recognized, and if not, then challenge the user with either a CAPTCHA or else a security question. Otherwise the phishing site can simply use the tendered username to query the real site for the security image, which defeats the purpose of having a security image. (A security question is probably better here since with a CAPTCHA the attacker could have humans sitting there answering the CAPTCHAs to get at the security images. Depends how paranoid you want to be.)
  3. A page after that that displays the security image and asks for the password.

I don't see this short, linear flow being sufficiently complex to warrant using Spring Web Flow.

I would just use straight Spring Web MVC for steps 1 and 2. I wouldn't use Spring Security for the initial login form, because Spring Security's login form expects a password and a login processing URL. Similarly, Spring Security doesn't provide special support for CAPTCHAs or security questions, so you can just use Spring Web MVC once again.

You can handle step 3 using Spring Security, since now you have a username and a password. The form login page should display the security image, and it should include the user-provided username as a hidden form field to make Spring Security happy when the user submits the login form. The only way to get to step 3 is to have a successful POST submission on step 1 (and 2 if applicable).

Hadoop MapReduce: Strange Result when Storing Previous Value in Memory in a Reduce Class (Java)

It is very inefficient to store all values in memory, so the objects are reused and loaded one at a time. See this other SO question for a good explanation. Summary:

[...] when looping through the Iterable value list, each Object instance is re-used, so it only keeps one instance around at a given time.

How do I hide the PHP explode delimiter from submitted form results?

Instead of adding the line breaks with nl2br() and then removing the line breaks with explode(), try using the line break character '\r' or '\n' or '\r\n'.

<?php     $options= file_get_contents("employees.txt");     $options=explode("\n",$options);        // try \r as well.      foreach ($options as $singleOption){         echo "<option value='".$singleOption."'>".$singleOption."</option>";     }   ?> 

This could also fix the issue if the problem was due to Google Spreadsheets reading the line breaks.

Got a NumberFormatException while trying to parse a text file for objects

I changed Scanner fin = new Scanner(file); to Scanner fin = new Scanner(new File(file)); and it works perfectly now. I didn't think the difference mattered but there you go.

Get Public URL for File - Google Cloud Storage - App Engine (Python)

You need to use get_serving_url from the Images API. As that page explains, you need to call create_gs_key() first to get the key to pass to the Images API.

Uploading into folder in FTP?

The folder is part of the URL you set when you create request: "ftp://www.contoso.com/test.htm". If you use "ftp://www.contoso.com/wibble/test.htm" then the file will be uploaded to a folder named wibble.

You may need to first use a request with Method = WebRequestMethods.Ftp.MakeDirectory to make the wibble folder if it doesn't already exist.

Speech input for visually impaired users without the need to tap the screen

The only way to get the iOS dictation is to sign up yourself through Nuance: http://dragonmobile.nuancemobiledeveloper.com/ - it's expensive, because it's the best. Presumably, Apple's contract prevents them from exposing an API.

The built in iOS accessibility features allow immobilized users to access dictation (and other keyboard buttons) through tools like VoiceOver and Assistive Touch. It may not be worth reinventing this if your users might be familiar with these tools.

how to put image in a bundle and pass it to another activity

So you can do it like this, but the limitation with the Parcelables is that the payload between activities has to be less than 1MB total. It's usually better to save the Bitmap to a file and pass the URI to the image to the next activity.

 protected void onCreate(Bundle savedInstanceState) {     setContentView(R.layout.my_layout);     Bitmap bitmap = getIntent().getParcelableExtra("image");     ImageView imageView = (ImageView) findViewById(R.id.imageview);     imageView.setImageBitmap(bitmap);  } 

Call japplet from jframe

First of all, Applets are designed to be run from within the context of a browser (or applet viewer), they're not really designed to be added into other containers.

Technically, you can add a applet to a frame like any other component, but personally, I wouldn't. The applet is expecting a lot more information to be available to it in order to allow it to work fully.

Instead, I would move all of the "application" content to a separate component, like a JPanel for example and simply move this between the applet or frame as required...

ps- You can use f.setLocationRelativeTo(null) to center the window on the screen ;)

Updated

You need to go back to basics. Unless you absolutely must have one, avoid applets until you understand the basics of Swing, case in point...

Within the constructor of GalzyTable2 you are doing...

JApplet app = new JApplet(); add(app); app.init(); app.start(); 

...Why are you adding another applet to an applet??

Case in point...

Within the main method, you are trying to add the instance of JFrame to itself...

f.getContentPane().add(f, button2); 

Instead, create yourself a class that extends from something like JPanel, add your UI logical to this, using compound components if required.

Then, add this panel to whatever top level container you need.

Take the time to read through Creating a GUI with Swing

Updated with example

import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.EventQueue; import java.awt.event.ActionEvent; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException;  public class GalaxyTable2 extends JPanel {      private static final int PREF_W = 700;     private static final int PREF_H = 600;      String[] columnNames                     = {"Phone Name", "Brief Description", "Picture", "price",                         "Buy"};  // Create image icons     ImageIcon Image1 = new ImageIcon(                     getClass().getResource("s1.png"));     ImageIcon Image2 = new ImageIcon(                     getClass().getResource("s2.png"));     ImageIcon Image3 = new ImageIcon(                     getClass().getResource("s3.png"));     ImageIcon Image4 = new ImageIcon(                     getClass().getResource("s4.png"));     ImageIcon Image5 = new ImageIcon(                     getClass().getResource("note.png"));     ImageIcon Image6 = new ImageIcon(                     getClass().getResource("note2.png"));     ImageIcon Image7 = new ImageIcon(                     getClass().getResource("note3.png"));      Object[][] rowData = {         {"Galaxy S", "3G Support,CPU 1GHz",             Image1, 120, false},         {"Galaxy S II", "3G Support,CPU 1.2GHz",             Image2, 170, false},         {"Galaxy S III", "3G Support,CPU 1.4GHz",             Image3, 205, false},         {"Galaxy S4", "4G Support,CPU 1.6GHz",             Image4, 230, false},         {"Galaxy Note", "4G Support,CPU 1.4GHz",             Image5, 190, false},         {"Galaxy Note2 II", "4G Support,CPU 1.6GHz",             Image6, 190, false},         {"Galaxy Note 3", "4G Support,CPU 2.3GHz",             Image7, 260, false},};      MyTable ss = new MyTable(                     rowData, columnNames);      // Create a table     JTable jTable1 = new JTable(ss);      public GalaxyTable2() {         jTable1.setRowHeight(70);          add(new JScrollPane(jTable1),                         BorderLayout.CENTER);          JPanel buttons = new JPanel();          JButton button = new JButton("Home");         buttons.add(button);         JButton button2 = new JButton("Confirm");         buttons.add(button2);          add(buttons, BorderLayout.SOUTH);     }      @Override      public Dimension getPreferredSize() {         return new Dimension(PREF_W, PREF_H);     }      public void actionPerformed(ActionEvent e) {         new AMainFrame7().setVisible(true);     }      public static void main(String[] args) {          EventQueue.invokeLater(new Runnable() {             @Override             public void run() {                 try {                     UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());                 } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {                     ex.printStackTrace();                 }                  JFrame frame = new JFrame("Testing");                 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);                 frame.add(new GalaxyTable2());                 frame.pack();                 frame.setLocationRelativeTo(null);                 frame.setVisible(true);             }         });     } } 

You also seem to have a lack of understanding about how to use layout managers.

Take the time to read through Creating a GUI with Swing and Laying components out in a container

FragmentActivity to Fragment

first of all;

a Fragment must be inside a FragmentActivity, that's the first rule,

a FragmentActivity is quite similar to a standart Activity that you already know, besides having some Fragment oriented methods

second thing about Fragments, is that there is one important method you MUST call, wich is onCreateView, where you inflate your layout, think of it as the setContentLayout

here is an example:

    @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {     mView       = inflater.inflate(R.layout.fragment_layout, container, false);       return mView; } 

and continu your work based on that mView, so to find a View by id, call mView.findViewById(..);


for the FragmentActivity part:

the xml part "must" have a FrameLayout in order to inflate a fragment in it

        <FrameLayout             android:id="@+id/content_frame"             android:layout_width="match_parent"             android:layout_height="match_parent"  >         </FrameLayout> 

as for the inflation part

getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, new YOUR_FRAGMENT, "TAG").commit();


begin with these, as there is tons of other stuf you must know about fragments and fragment activities, start of by reading something about it (like life cycle) at the android developer site

RegisterStartupScript from code behind not working when Update Panel is used

You need to use ScriptManager.RegisterStartupScript for Ajax.

protected void ButtonPP_Click(object sender, EventArgs e) {     if (radioBtnACO.SelectedIndex < 0)     {         string csname1 = "PopupScript";          var cstext1 = new StringBuilder();         cstext1.Append("alert('Please Select Criteria!')");          ScriptManager.RegisterStartupScript(this, GetType(), csname1,             cstext1.ToString(), true);     } } 

Laravel 4 with Sentry 2 add user to a group on Registration

Somehow, where you are using Sentry, you're not using its Facade, but the class itself. When you call a class through a Facade you're not really using statics, it's just looks like you are.

Do you have this:

use Cartalyst\Sentry\Sentry; 

In your code?

Ok, but if this line is working for you:

$user = $this->sentry->register(array(     'username' => e($data['username']),     'email' => e($data['email']),      'password' => e($data['password'])     )); 

So you already have it instantiated and you can surely do:

$adminGroup = $this->sentry->findGroupById(5); 

php & mysql query not echoing in html with tags?

Change <?php echo $proxy ?> to ' . $proxy . '.

You use <?php when you're outputting HTML by leaving PHP mode with ?>. When you using echo, you have to use concatenation, or wrap your string in double quotes and use interpolation.

Target class controller does not exist - Laravel 8

The Laravel 8 documentation actually answers this issue more succinctly and clearly than any of the answers here:

Routing Namespace Updates

In previous releases of Laravel, the RouteServiceProvider contained a $namespace property. This property's value would automatically be prefixed onto controller route definitions and calls to the action helper / URL::action method. In Laravel 8.x, this property is null by default. This means that no automatic namespace prefixing will be done by Laravel. Therefore, in new Laravel 8.x applications, controller route definitions should be defined using standard PHP callable syntax:

use App\Http\Controllers\UserController;

Route::get('/users', [UserController::class, 'index']);

Calls to the action related methods should use the same callable syntax:

action([UserController::class, 'index']);

return Redirect::action([UserController::class, 'index']);

If you prefer Laravel 7.x style controller route prefixing, you may simply add the $namespace property into your application's RouteServiceProvider.


There's no explanation as to why Taylor Otwell added this maddening gotcha, but I presume he had his reasons.

iPhone is not available. Please reconnect the device

My experience, yesterday my iOS 13.6 is supported by Xcode 11.7 and now today the Xcode rejected my iPhone and I update the Xcode to version 12 and everything get back on track.

Solution:

Update your Xcode to the latest version.

Hint: there is no need to update iOS.

DevTools failed to load SourceMap: Could not load content for chrome-extension

Right: it has nothing to do with your code. I've found two valid solutions to this warning (not just disabling it). To better understand what a SourceMap is, I suggest you check out this answer, where it explains how it's something that helps you debug:

The .map files are for js and css (and now ts too) files that have been minified. They are called SourceMaps. When you minify a file, like the angular.js file, it takes thousands of lines of pretty code and turns it into only a few lines of ugly code. Hopefully, when you are shipping your code to production, you are using the minified code instead of the full, unminified version. When your app is in production, and has an error, the sourcemap will help take your ugly file, and will allow you to see the original version of the code. If you didn't have the sourcemap, then any error would seem cryptic at best.

  1. First solution: apparently, Mr Heelis was the closest one: you should add the .map file and there are some tools that help you with this problem (Grunt, Gulp and Google closure for example, quoting the answer). Otherwise you can download the .map file from official sites like Bootstrap, jquery, font-awesome, preload and so on.. (maybe installing things like popper or swiper by the npm command in a random folder and copying just the .map file in your js/css destination folder)

  2. Second solution (the one I used): add the source files using a CDN (here all the advantages of using a CDN). Using the Content delivery network (CDN) you can simply add the cdn link, instead of the path to your folder. You can find cdn on official websites (Bootstrap, jquery, popper, etc..) or you can easily search on some websites like cloudflare, cdnjs, etc..

When adding a Javascript library, Chrome complains about a missing source map, why?

This is what worked for me: instead of

<script src="https://cdn.jsdelivr.net/npm/@tensorflow/tfjs"></script>

try

<script src="https://cdn.jsdelivr.net/npm/@tensorflow/tfjs/dist/tf.min.js"> </script>

After that change I am not seeing the error anymore.

error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class

Restarting your server may not work always. I have got this error when I imported MatFormFieldModule.

In app.module.ts, I have imported MatFormField instead of MatFormFieldModule which lead to this error.

Now change it and restart the server, Hope this answer helps you.

error TS1086: An accessor cannot be declared in an ambient context in Angular 9

I solved the same issue by following steps:

Check the angular version: Using command: ng version My angular version is: Angular CLI: 7.3.10

After that I have support version of ngx bootstrap from the link: https://www.npmjs.com/package/ngx-bootstrap

In package.json file update the version: "bootstrap": "^4.5.3", "@ng-bootstrap/ng-bootstrap": "^4.2.2",

Now after updating package.json, use the command npm update

After this use command ng serve and my error got resolved

TS1086: An accessor cannot be declared in ambient context

Quick solution: Update package.json

"devDependencies": {
   ...
   "typescript": "~3.7.4",
 }

In tsconfig.json

{
    ...,
    "angularCompilerOptions": {
       ...,
       "disableTypeScriptVersionCheck": true
    }
}

then remove node_modules folder and reinstall with

npm install

For more visit here

Maven dependencies are failing with a 501 error

This error occured to me too. I did what Muhammad umer said above. But, it only solved error for spring-boot-dependencies and spring-boot-dependencies has child dependencies. Now, there were 21 errors. Previously, it was 2 errors. Like this:

Non-resolvable import POM: Could not transfer artifact org.springframework.cloud:spring-cloud-dependencies:pom:Hoxton.SR3 from/to central

and also https required in the error message.

I updated the maven version from 3.2.2 to 3.6.3 and java version from 8 to 11. Now, all errors of https required are gone.

To update maven version

  1. Download latest maven from here: download maven
  2. Unzip and move it to /opt/maven/
  3. Set the path export PATH=$PATH:/opt/maven/bin
  4. And, also remove old maven from PATH

Replace specific text with a redacted version using Python

You can do it using named-entity recognition (NER). It's fairly simple and there are out-of-the-shelf tools out there to do it, such as spaCy.

NER is an NLP task where a neural network (or other method) is trained to detect certain entities, such as names, places, dates and organizations.

Example:

Sponge Bob went to South beach, he payed a ticket of $200!
I know, Michael is a good person, he goes to McDonalds, but donates to charity at St. Louis street.

Returns:

NER with spacy

Just be aware that this is not 100%!

Here are a little snippet for you to try out:

import spacy

phrases = ['Sponge Bob went to South beach, he payed a ticket of $200!', 'I know, Michael is a good person, he goes to McDonalds, but donates to charity at St. Louis street.']
nlp = spacy.load('en')
for phrase in phrases:
   doc = nlp(phrase)
   replaced = ""
   for token in doc:
      if token in doc.ents:
         replaced+="XXXX "
      else:
         replaced+=token.text+" "

Read more here: https://spacy.io/usage/linguistic-features#named-entities

You could, instead of replacing with XXXX, replace based on the entity type, like:

if ent.label_ == "PERSON":
   replaced += "<PERSON> "

Then:

import re, random

personames = ["Jack", "Mike", "Bob", "Dylan"]

phrase = re.replace("<PERSON>", random.choice(personames), phrase)

What's the net::ERR_HTTP2_PROTOCOL_ERROR about?

In my case (nginx on windows proxying an app while serving static assets on its own) page was showing multiple assets including 14 bigger pictures; those errors were shown for about 5 of those images exactly after 60 seconds; in my case it was a default send_timeout of 60s making those image requests fail; increasing the send_timeout made it work

I am not sure what is causing nginx on windows to serve those files so slow - it is only 11.5MB of resources which takes nginx almost 2 minutes to serve but I guess it is subject for another thread

How to fix "set SameSite cookie to none" warning?

I'm also in a "trial and error" for that, but this answer from Google Chrome Labs' Github helped me a little. I defined it into my main file and it worked - well, for only one third-party domain. Still making tests, but I'm eager to update this answer with a better solution :)

EDIT: I'm using PHP 7.4 now, and this syntax is working good (Sept 2020):

$cookie_options = array(
  'expires' => time() + 60*60*24*30,
  'path' => '/',
  'domain' => '.domain.com', // leading dot for compatibility or use subdomain
  'secure' => true, // or false
  'httponly' => false, // or false
  'samesite' => 'None' // None || Lax || Strict
);

setcookie('cors-cookie', 'my-site-cookie', $cookie_options);

If you have PHP 7.2 or lower (as Robert's answered below):

setcookie('key', 'value', time()+(7*24*3600), "/; SameSite=None; Secure");

If your host is already updated to PHP 7.3, you can use (thanks to Mahn's comment):

setcookie('cookieName', 'cookieValue', [
  'expires' => time()+(7*24*3600,
  'path' => '/',
  'domain' => 'domain.com',
  'samesite' => 'None',
  'secure' => true,
  'httponly' => true
]);

Another thing you can try to check the cookies, is to enable the flag below, which—in their own words—"will add console warning messages for every single cookie potentially affected by this change":

chrome://flags/#cookie-deprecation-messages

See the whole code at: https://github.com/GoogleChromeLabs/samesite-examples/blob/master/php.md, they have the code for same-site-cookies too.

How to resolve the error on 'react-native start'

A PR with a fix has been merged in the metro repository. Now we just need to wait until the next release. For now the best option is to downgrade to NodeJS v12.10.0. As Brandon pointed out, modifying anything in node_modules/ isa really bad practice and will not be a final solution.

How to fix error "ERROR: Command errored out with exit status 1: python." when trying to install django-heroku using pip

You need to add the package containing the executable pg_config.

A prior answer should have details you need: pg_config executable not found

Element implicitly has an 'any' type because expression of type 'string' can't be used to index

When we do something like this obj[key] Typescript can't know for sure if that key exists in that object. What I did:

Object.entries(data).forEach(item => {
    formData.append(item[0], item[1]);
});

Invalid hook call. Hooks can only be called inside of the body of a function component

You can convert class component to hooks,but Material v4 has a withStyles HOC. https://material-ui.com/styles/basics/#higher-order-component-api Using this HOC you can keep your code unchanged.

Schema validation failed with the following errors: Data path ".builders['app-shell']" should have required property 'class'

I got the same error when upgraded angular from 6 to 8.

Simple update angular cli to latest version & node version to 10+.

1) Visit this link to get the latest node version. Angular 8 requires 10+.
2) Execute npm i @angular/cli@latest to update cli.


This is what I have currently

enter image description here

Make a VStack fill the width of the screen in SwiftUI

I know this will not work for everyone, but I thought it interesting that just adding a Divider solves for this.

struct DividerTest: View {
var body: some View {
    VStack(alignment: .leading) {
        Text("Foo")
        Text("Bar")
        Divider()
    }.background(Color.red)
  }
}

Access blocked by CORS policy: Response to preflight request doesn't pass access control check

CORS headers should be sent from the server. If you use PHP it will be like this:

header('Access-Control-Allow-Origin: your-host');
header('Access-Control-Allow-Credentials: true');
header('Access-Control-Allow-Methods: your-methods like POST,GET');
header('Access-Control-Allow-Headers: content-type or other');
header('Content-Type: application/json');

How to style components using makeStyles and still have lifecycle methods in Material UI?

Another one solution can be used for class components - just override default MUI Theme properties with MuiThemeProvider. This will give more flexibility in comparison with other methods - you can use more than one MuiThemeProvider inside your parent component.

simple steps:

  1. import MuiThemeProvider to your class component
  2. import createMuiTheme to your class component
  3. create new theme
  4. wrap target MUI component you want to style with MuiThemeProvider and your custom theme

please, check this doc for more details: https://material-ui.com/customization/theming/

_x000D_
_x000D_
import React from 'react';
import PropTypes from 'prop-types';
import Button from '@material-ui/core/Button';

import { MuiThemeProvider } from '@material-ui/core/styles';
import { createMuiTheme } from '@material-ui/core/styles';

const InputTheme = createMuiTheme({
    overrides: {
        root: {
            background: 'linear-gradient(45deg, #FE6B8B 30%, #FF8E53 90%)',
            border: 0,
            borderRadius: 3,
            boxShadow: '0 3px 5px 2px rgba(255, 105, 135, .3)',
            color: 'white',
            height: 48,
            padding: '0 30px',
        },
    }
});

class HigherOrderComponent extends React.Component {

    render(){
        const { classes } = this.props;
        return (
            <MuiThemeProvider theme={InputTheme}>
                <Button className={classes.root}>Higher-order component</Button>
            </MuiThemeProvider>
        );
    }
}

HigherOrderComponent.propTypes = {
    classes: PropTypes.object.isRequired,
};

export default HigherOrderComponent;
_x000D_
_x000D_
_x000D_

Understanding esModuleInterop in tsconfig file

Problem statement

Problem occurs when we want to import CommonJS module into ES6 module codebase.

Before these flags we had to import CommonJS modules with star (* as something) import:

// node_modules/moment/index.js
exports = moment
// index.ts file in our app
import * as moment from 'moment'
moment(); // not compliant with es6 module spec

// transpiled js (simplified):
const moment = require("moment");
moment();

We can see that * was somehow equivalent to exports variable. It worked fine, but it wasn't compliant with es6 modules spec. In spec, the namespace record in star import (moment in our case) can be only a plain object, not callable (moment() is not allowed).

Solution

With flag esModuleInterop we can import CommonJS modules in compliance with es6 modules spec. Now our import code looks like this:

// index.ts file in our app
import moment from 'moment'
moment(); // compliant with es6 module spec

// transpiled js with esModuleInterop (simplified):
const moment = __importDefault(require('moment'));
moment.default();

It works and it's perfectly valid with es6 modules spec, because moment is not namespace from star import, it's default import.

But how does it work? As you can see, because we did a default import, we called the default property on a moment object. But we didn't declare a default property on the exports object in the moment library. The key is the __importDefault function. It assigns module (exports) to the default property for CommonJS modules:

var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};

As you can see, we import es6 modules as they are, but CommonJS modules are wrapped into an object with the default key. This makes it possible to import defaults on CommonJS modules.

__importStar does the similar job - it returns untouched esModules, but translates CommonJS modules into modules with a default property:

// index.ts file in our app
import * as moment from 'moment'

// transpiled js with esModuleInterop (simplified):
const moment = __importStar(require("moment"));
// note that "moment" is now uncallable - ts will report error!
var __importStar = (this && this.__importStar) || function (mod) {
    if (mod && mod.__esModule) return mod;
    var result = {};
    if (mod != null) for (var k in mod) if (Object.hasOwnProperty.call(mod, k)) result[k] = mod[k];
    result["default"] = mod;
    return result;
};

Synthetic imports

And what about allowSyntheticDefaultImports - what is it for? Now the docs should be clear:

Allow default imports from modules with no default export. This does not affect code emit, just typechecking.

In moment typings we don't have specified default export, and we shouldn't have, because it's available only with flag esModuleInterop on. So allowSyntheticDefaultImports will not report an error if we want to import default from a third-party module which doesn't have a default export.

How to fix ReferenceError: primordials is not defined in node

Use following commands to install node v11.15.0 and gulp v3.9.1:

npm install -g n

sudo n 11.15.0

npm install gulp@^3.9.1
npm install 
npm rebuild node-sass

Will solve this issue:

ReferenceError: primordials is not defined in node

How to fix missing dependency warning when using useEffect React Hook?

Just pass the function as the argument in the array of useEffect...

useEffect(() => {
   functionName()
}, [functionName])

Module not found: Error: Can't resolve 'core-js/es6'

Ended up to have a file named polyfill.js in projectpath\src\polyfill.js That file only contains this line: import 'core-js'; this polyfills not only es-6, but is the correct way to use core-js since version 3.0.0.

I added the polyfill.js to my webpack-file entry attribute like this:

entry: ['./src/main.scss', './src/polyfill.js', './src/main.jsx']

Works perfectly.

I also found some more information here : https://github.com/zloirock/core-js/issues/184

The library author (zloirock) claims:

ES6 changes behaviour almost all features added in ES5, so core-js/es6 entry point includes almost all of them. Also, as you wrote, it's required for fixing broken browser implementations.

(Quotation https://github.com/zloirock/core-js/issues/184 from zloirock)

So I think import 'core-js'; is just fine.

How to set value to form control in Reactive Forms in Angular

The "usual" solution is make a function that return an empty formGroup or a fullfilled formGroup

createFormGroup(data:any)
{
 return this.fb.group({
   user: [data?data.user:null],
   questioning: [data?data.questioning:null, Validators.required],
   questionType: [data?data.questionType, Validators.required],
   options: new FormArray([this.createArray(data?data.options:null])
})
}

//return an array of formGroup
createArray(data:any[]|null):FormGroup[]
{
   return data.map(x=>this.fb.group({
        ....
   })
}

then, in SUBSCRIBE, you call the function

this.qService.editQue([params["id"]]).subscribe(res => {
  this.editqueForm = this.createFormGroup(res);
});

be carefull!, your form must include an *ngIf to avoid initial error

<form *ngIf="editqueForm" [formGroup]="editqueForm">
   ....
</form>

Browserslist: caniuse-lite is outdated. Please run next command `npm update caniuse-lite browserslist`

Many advise you to remove the package-lock.json or the yarn.lock. This is clearly a bad idea!

I am using Yarn and I was able to correct this problem by removing only the caniuse-db and caniuse-lite entries in my yarn.lock and doing a yarn.

It is not necessary to break the main function of the lockfile by deleting it.

The POST method is not supported for this route. Supported methods: GET, HEAD. Laravel

I just removed the slash at the end of url and it began working... /managers/games/id/push/ to:

$http({
  method: 'POST',
  url: "/managers/games/id/push",

This may have to do with upgrading to laravel 5.8?

Jupyter Notebook not saving: '_xsrf' argument missing from post

Open the developer setting and click console and type the following

JSON.parse(document.getElementById('jupyter-config-data').textContent).token

Then try saving the Notebook. The notebook that was not saving previously will save now.

Why am I seeing net::ERR_CLEARTEXT_NOT_PERMITTED errors after upgrading to Cordova Android 8?

you should add

<base-config cleartextTrafficPermitted="true">
    <trust-anchors>
        <certificates src="system" />
    </trust-anchors>
</base-config>

to

resources/android/xml/network_security_config.xml

like this

<network-security-config>
<base-config cleartextTrafficPermitted="true">
    <trust-anchors>
        <certificates src="system" />
    </trust-anchors>
</base-config>

<domain-config cleartextTrafficPermitted="true">
    <domain includeSubdomains="true">localhost</domain>
</domain-config> </network-security-config>

How to Install pip for python 3.7 on Ubuntu 18?

I used apt-get to install python3.7 in ubuntu18.04. The installations are as follows.

  1. install python3.7
sudo apt-get install python3.7 
  1. install pip3. It should be noted that this may install pip3 for python3.6.
sudo apt-get install python3-pip 
  1. change the default of python3 for python3.7. This is where the magic is, which will make the pip3 refer to python3.7.
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.7 1

Hope it works for you.

Flutter Countdown Timer

You can use this plugin timer_builder

timer_builder widget that rebuilds itself on scheduled, periodic, or dynamically generated time events.

Examples

Periodic rebuild

import 'package:timer_builder/timer_builder.dart';

class ClockWidget extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return TimerBuilder.periodic(Duration(seconds: 1),
      builder: (context) {
        return Text("${DateTime.now()}");
      }
    );
  }
  
}

Rebuild on a schedule

import 'package:timer_builder/timer_builder.dart';

class StatusIndicator extends StatelessWidget {

  final DateTime startTime;
  final DateTime endTime;
  
  StatusIndicator(this.startTime, this.endTime);
  
  @override
  Widget build(BuildContext context) {
    return TimerBuilder.scheduled([startTime, endTime],
      builder: (context) {
        final now = DateTime.now();
        final started = now.compareTo(startTime) >= 0;
        final ended = now.compareTo(endTime) >= 0;
        return Text(started ? ended ? "Ended": "Started": "Not Started");
      }
    );
  }
  
}

enter image description here

Warning: "continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"?

The issue looks to me to be a backward incompatibility with PHP 7.3 for the continue keyword in Switch statements. Take a look at the "Continue Targeting Switch issues Warning" section in Backward Incompatible Changes.

I ran into the same issue with Symfony 3.3 using PHP 7.3 and downgrading to PHP 7.2 resolved the warning.

JS file gets a net::ERR_ABORTED 404 (Not Found)

As mentionned in comments: you need a way to send your static files to the client. This can be achieved with a reverse proxy like Nginx, or simply using express.static().

Put all your "static" (css, js, images) files in a folder dedicated to it, different from where you put your "views" (html files in your case). I'll call it static for the example. Once it's done, add this line in your server code:

app.use("/static", express.static('./static/'));

This will effectively serve every file in your "static" folder via the /static route.

Querying your index.js file in the client thus becomes:

<script src="static/index.js"></script>

useState set method not reflecting change immediately

I just finished a rewrite with useReducer, following @kentcdobs article (ref below) which really gave me a solid result that suffers not one bit from these closure problems.

see: https://kentcdodds.com/blog/how-to-use-react-context-effectively

I condensed his readable boilerplate to my preferred level of DRYness -- reading his sandbox implementation will show you how it actually works.

Enjoy, I know I am !!

import React from 'react'

// ref: https://kentcdodds.com/blog/how-to-use-react-context-effectively

const ApplicationDispatch = React.createContext()
const ApplicationContext = React.createContext()

function stateReducer(state, action) {
  if (state.hasOwnProperty(action.type)) {
    return { ...state, [action.type]: state[action.type] = action.newValue };
  }
  throw new Error(`Unhandled action type: ${action.type}`);
}

const initialState = {
  keyCode: '',
  testCode: '',
  testMode: false,
  phoneNumber: '',
  resultCode: null,
  mobileInfo: '',
  configName: '',
  appConfig: {},
};

function DispatchProvider({ children }) {
  const [state, dispatch] = React.useReducer(stateReducer, initialState);
  return (
    <ApplicationDispatch.Provider value={dispatch}>
      <ApplicationContext.Provider value={state}>
        {children}
      </ApplicationContext.Provider>
    </ApplicationDispatch.Provider>
  )
}

function useDispatchable(stateName) {
  const context = React.useContext(ApplicationContext);
  const dispatch = React.useContext(ApplicationDispatch);
  return [context[stateName], newValue => dispatch({ type: stateName, newValue })];
}

function useKeyCode() { return useDispatchable('keyCode'); }
function useTestCode() { return useDispatchable('testCode'); }
function useTestMode() { return useDispatchable('testMode'); }
function usePhoneNumber() { return useDispatchable('phoneNumber'); }
function useResultCode() { return useDispatchable('resultCode'); }
function useMobileInfo() { return useDispatchable('mobileInfo'); }
function useConfigName() { return useDispatchable('configName'); }
function useAppConfig() { return useDispatchable('appConfig'); }

export {
  DispatchProvider,
  useKeyCode,
  useTestCode,
  useTestMode,
  usePhoneNumber,
  useResultCode,
  useMobileInfo,
  useConfigName,
  useAppConfig,
}

with a usage similar to this:

import { useHistory } from "react-router-dom";

// https://react-bootstrap.github.io/components/alerts
import { Container, Row } from 'react-bootstrap';

import { useAppConfig, useKeyCode, usePhoneNumber } from '../../ApplicationDispatchProvider';

import { ControlSet } from '../../components/control-set';
import { keypadClass } from '../../utils/style-utils';
import { MaskedEntry } from '../../components/masked-entry';
import { Messaging } from '../../components/messaging';
import { SimpleKeypad, HandleKeyPress, ALT_ID } from '../../components/simple-keypad';

export const AltIdPage = () => {
  const history = useHistory();
  const [keyCode, setKeyCode] = useKeyCode();
  const [phoneNumber, setPhoneNumber] = usePhoneNumber();
  const [appConfig, setAppConfig] = useAppConfig();

  const keyPressed = btn => {
    const maxLen = appConfig.phoneNumberEntry.entryLen;
    const newValue = HandleKeyPress(btn, phoneNumber).slice(0, maxLen);
    setPhoneNumber(newValue);
  }

  const doSubmit = () => {
    history.push('s');
  }

  const disableBtns = phoneNumber.length < appConfig.phoneNumberEntry.entryLen;

  return (
    <Container fluid className="text-center">
      <Row>
        <Messaging {...{ msgColors: appConfig.pageColors, msgLines: appConfig.entryMsgs.altIdMsgs }} />
      </Row>
      <Row>
        <MaskedEntry {...{ ...appConfig.phoneNumberEntry, entryColors: appConfig.pageColors, entryLine: phoneNumber }} />
      </Row>
      <Row>
        <SimpleKeypad {...{ keyboardName: ALT_ID, themeName: appConfig.keyTheme, keyPressed, styleClass: keypadClass }} />
      </Row>
      <Row>
        <ControlSet {...{ btnColors: appConfig.buttonColors, disabled: disableBtns, btns: [{ text: 'Submit', click: doSubmit }] }} />
      </Row>
    </Container>
  );
};

AltIdPage.propTypes = {};

Now everything persists smoothly everywhere across all my pages

Nice!

Thanks Kent!

Can't perform a React state update on an unmounted component

Functional component approach (Minimal Demo, Full Demo):

import React, { useState } from "react";
import { useAsyncEffect } from "use-async-effect2";
import cpFetch from "cp-fetch"; //cancellable c-promise fetch wrapper

export default function TestComponent(props) {
  const [text, setText] = useState("");

  useAsyncEffect(
    function* () {
      setText("fetching...");
      const response = yield cpFetch(props.url);
      const json = yield response.json();
      setText(`Success: ${JSON.stringify(json)}`);
    },
    [props.url]
  );

  return <div>{text}</div>;
}

Class component (Live demo)

import { async, listen, cancel, timeout } from "c-promise2";
import cpFetch from "cp-fetch";

export class TestComponent extends React.Component {
  state = {
    text: ""
  };

  @timeout(5000)
  @listen
  @async
  *componentDidMount() {
    console.log("mounted");
    const response = yield cpFetch(this.props.url);
    this.setState({ text: `json: ${yield response.text()}` });
  }

  render() {
    return <div>{this.state.text}</div>;
  }

  @cancel()
  componentWillUnmount() {
    console.log("unmounted");
  }
}

HTTP Error 500.30 - ANCM In-Process Start Failure

In my case it was database connection problem. This error needs to be more clear. I hope they will do it in the future. Basically it is a problem at ConfigureServices function in Startup. My advise is try to add all lines try catch in ConfigureServices function and you can findout where is problem.

Can I set state inside a useEffect hook

For future purposes, this may help too:

It's ok to use setState in useEffect you just need to have attention as described already to not create a loop.

But it's not the only problem that may occur. See below:

Imagine that you have a component Comp that receives props from parent and according to a props change you want to set Comp's state. For some reason, you need to change for each prop in a different useEffect:

DO NOT DO THIS

useEffect(() => {
  setState({ ...state, a: props.a });
}, [props.a]);

useEffect(() => {
  setState({ ...state, b: props.b });
}, [props.b]);

It may never change the state of a as you can see in this example: https://codesandbox.io/s/confident-lederberg-dtx7w

The reason why this happen in this example it's because both useEffects run in the same react cycle when you change both prop.a and prop.b so the value of {...state} when you do setState are exactly the same in both useEffect because they are in the same context. When you run the second setState it will replace the first setState.

DO THIS INSTEAD

The solution for this problem is basically call setState like this:

useEffect(() => {
  setState(state => ({ ...state, a: props.a }));
}, [props.a]);

useEffect(() => {
  setState(state => ({ ...state, b: props.b }));
}, [props.b]);

Check the solution here: https://codesandbox.io/s/mutable-surf-nynlx

Now, you always receive the most updated and correct value of the state when you proceed with the setState.

I hope this helps someone!

Android Gradle 5.0 Update:Cause: org.jetbrains.plugins.gradle.tooling.util

Issue has been resolved after updating Android studio version to 3.3-rc2 or latest released version.

cr: @shadowsheep

have to change version under /gradle/wrapper/gradle-wrapper.properties. refer below url https://stackoverflow.com/a/56412795/7532946

FlutterError: Unable to load asset

  1. you should start image path with assets word:

image: AssetImage('assets/images/pizza0.png')

  1. you must add each sub folder in a new line in pubspec.yaml

Pandas Merging 101

In this answer, I will consider practical examples.

The first one, is of pandas.concat.

The second one, of merging dataframes from the index of one and the column of another one.


1. pandas.concat

Considering the following DataFrames with the same column names:

Preco2018 with size (8784, 5)

DataFrame 1

Preco 2019 with size (8760, 5)

DataFrame 2

That have the same column names.

You can combine them using pandas.concat, by simply

import pandas as pd

frames = [Preco2018, Preco2019]

df_merged = pd.concat(frames)

Which results in a DataFrame with the following size (17544, 5)

DataFrame result of the combination of two dataframes

If you want to visualize, it ends up working like this

How concat works

(Source)


2. Merge by Column and Index

In this part, I will consider a specific case: If one wants to merge the index of one dataframe and the column of another dataframe.

Let's say one has the dataframe Geo with 54 columns, being one of the columns the Date Data, which is of type datetime64[ns].

enter image description here

And the dataframe Price that has one column with the price and the index corresponds to the dates

enter image description here

In this specific case, to merge them, one uses pd.merge

merged = pd.merge(Price, Geo, left_index=True, right_on='Data')

Which results in the following dataframe

enter image description here

Why do I keep getting Delete 'cr' [prettier/prettier]?

Add this to your .prettierrc file and open the VSCODE

"endOfLine": "auto"

Has been blocked by CORS policy: Response to preflight request doesn’t pass access control check

I believe this is the simplest example:

header := w.Header()
header.Add("Access-Control-Allow-Origin", "*")
header.Add("Access-Control-Allow-Methods", "DELETE, POST, GET, OPTIONS")
header.Add("Access-Control-Allow-Headers", "Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With")

You can also add a header for Access-Control-Max-Age and of course you can allow any headers and methods that you wish.

Finally you want to respond to the initial request:

if r.Method == "OPTIONS" {
    w.WriteHeader(http.StatusOK)
    return
}

Edit (June 2019): We now use gorilla for this. Their stuff is more actively maintained and they have been doing this for a really long time. Leaving the link to the old one, just in case.

Old Middleware Recommendation below: Of course it would probably be easier to just use middleware for this. I don't think I've used it, but this one seems to come highly recommended.

How can I force component to re-render with hooks in React?

You should preferably only have your component depend on state and props and it will work as expected, but if you really need a function to force the component to re-render, you could use the useState hook and call the function when needed.

Example

_x000D_
_x000D_
const { useState, useEffect } = React;_x000D_
_x000D_
function Foo() {_x000D_
  const [, forceUpdate] = useState();_x000D_
_x000D_
  useEffect(() => {_x000D_
    setTimeout(forceUpdate, 2000);_x000D_
  }, []);_x000D_
_x000D_
  return <div>{Date.now()}</div>;_x000D_
}_x000D_
_x000D_
ReactDOM.render(<Foo />, document.getElementById("root"));
_x000D_
<script src="https://unpkg.com/[email protected]/umd/react.production.min.js"></script>_x000D_
<script src="https://unpkg.com/[email protected]/umd/react-dom.production.min.js"></script>_x000D_
_x000D_
<div id="root"></div>
_x000D_
_x000D_
_x000D_

Set the space between Elements in Row Flutter

MainAxisAlignment

start - Place the children as close to the start of the main axis as possible.

enter image description here

end - Place the children as close to the end of the main axis as possible.

enter image description here

center - Place the children as close to the middle of the main axis as possible.

enter image description here

spaceBetween - Place the free space evenly between the children.

enter image description here

spaceAround - Place the free space evenly between the children as well as half of that space before and after the first and last child.

enter image description here

spaceEvenly - Place the free space evenly between the children as well as before and after the first and last child.

enter image description here

Example:

  child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: <Widget>[
          Text('Row1'),
          Text('Row2')
        ],
      )

A fatal error occurred while creating a TLS client credential. The internal error state is 10013

After making no changes to a production server we began receiving this error. After trying several different things and thinking that perhaps there were DNS issues, restarting IIS fixed the issue (restarting only the site did not fix the issue). It likely won't work for everyone but if we tried that first it would have saved a lot of time.

How to call loading function with React useEffect only once

Pass an empty array as the second argument to useEffect. This effectively tells React, quoting the docs:

This tells React that your effect doesn’t depend on any values from props or state, so it never needs to re-run.

Here's a snippet which you can run to show that it works:

_x000D_
_x000D_
function App() {_x000D_
  const [user, setUser] = React.useState(null);_x000D_
_x000D_
  React.useEffect(() => {_x000D_
    fetch('https://randomuser.me/api/')_x000D_
      .then(results => results.json())_x000D_
      .then(data => {_x000D_
        setUser(data.results[0]);_x000D_
      });_x000D_
  }, []); // Pass empty array to only run once on mount._x000D_
  _x000D_
  return <div>_x000D_
    {user ? user.name.first : 'Loading...'}_x000D_
  </div>;_x000D_
}_x000D_
_x000D_
ReactDOM.render(<App/>, document.getElementById('app'));
_x000D_
<script src="https://unpkg.com/[email protected]/umd/react.development.js"></script>_x000D_
<script src="https://unpkg.com/[email protected]/umd/react-dom.development.js"></script>_x000D_
_x000D_
<div id="app"></div>
_x000D_
_x000D_
_x000D_

expected assignment or function call: no-unused-expressions ReactJS

In my case I had curly braces where it should have been parentheses.

const Button = () => {
    <button>Hello world</button>
}

Where it should have been:

const Button = () => (
    <button>Hello world</button>
)

The reason for this, as explained in the MDN Docs is that an arrow function wrapped by () will return the value it wraps, so if I wanted to use curly braces I had to add the return keyword, like so:

const Button = () => {
    return <button>Hello world</button>
}

ImageMagick security policy 'PDF' blocking conversion

As pointed out in some comments, you need to edit the policies of ImageMagick in /etc/ImageMagick-7/policy.xml. More particularly, in ArchLinux at the time of writing (05/01/2019) the following line is uncommented:

<policy domain="coder" rights="none" pattern="{PS,PS2,PS3,EPS,PDF,XPS}" />

Just wrap it between <!-- and --> to comment it, and pdf conversion should work again.

Flutter: RenderBox was not laid out

Reason for the error:

Column tries to expands in vertical axis, and so does the ListView, hence you need to constrain the height of ListView.


Solutions

  1. Use either Expanded or Flexible if you want to allow ListView to take up entire left space in Column.

    Column(
      children: <Widget>[
        Expanded(
          child: ListView(...),
        )
      ],
    )
    

  1. Use SizedBox if you want to restrict the size of ListView to a certain height.

    Column(
      children: <Widget>[
        SizedBox(
          height: 200, // constrain height
          child: ListView(),
        )
      ],
    )
    

  1. Use shrinkWrap, if your ListView isn't too big.

    Column(
      children: <Widget>[
        ListView(
          shrinkWrap: true, // use it
        )
      ],
    )
    

Space between Column's children in Flutter

Just use padding to wrap it like this:

Column(
  children: <Widget>[
  Padding(
    padding: EdgeInsets.all(8.0),
    child: Text('Hello World!'),
  ),
  Padding(
    padding: EdgeInsets.all(8.0),
    child: Text('Hello World2!'),
  )
]);

You can also use Container(padding...) or SizeBox(height: x.x). The last one is the most common but it will depents of how you want to manage the space of your widgets, I like to use padding if the space is part of the widget indeed and use sizebox for lists for example.

WebView showing ERR_CLEARTEXT_NOT_PERMITTED although site is HTTPS

Solution:

Add the below line in your application tag:

android:usesCleartextTraffic="true"

As shown below:

<application
    ....
    android:usesCleartextTraffic="true"
    ....>

UPDATE: If you have network security config such as: android:networkSecurityConfig="@xml/network_security_config"

No Need to set clear text traffic to true as shown above, instead use the below code:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        ....
        ....
    </domain-config>

    <base-config cleartextTrafficPermitted="false"/>
</network-security-config>  

Set the cleartextTrafficPermitted to true

Hope it helps.

pod has unbound PersistentVolumeClaims

You have to define a PersistentVolume providing disc space to be consumed by the PersistentVolumeClaim.

When using storageClass Kubernetes is going to enable "Dynamic Volume Provisioning" which is not working with the local file system.


To solve your issue:

  • Provide a PersistentVolume fulfilling the constraints of the claim (a size >= 100Mi)
  • Remove the storageClass-line from the PersistentVolumeClaim
  • Remove the StorageClass from your cluster

How do these pieces play together?

At creation of the deployment state-description it is usually known which kind (amount, speed, ...) of storage that application will need.
To make a deployment versatile you'd like to avoid a hard dependency on storage. Kubernetes' volume-abstraction allows you to provide and consume storage in a standardized way.

The PersistentVolumeClaim is used to provide a storage-constraint alongside the deployment of an application.

The PersistentVolume offers cluster-wide volume-instances ready to be consumed ("bound"). One PersistentVolume will be bound to one claim. But since multiple instances of that claim may be run on multiple nodes, that volume may be accessed by multiple nodes.

A PersistentVolume without StorageClass is considered to be static.

"Dynamic Volume Provisioning" alongside with a StorageClass allows the cluster to provision PersistentVolumes on demand. In order to make that work, the given storage provider must support provisioning - this allows the cluster to request the provisioning of a "new" PersistentVolume when an unsatisfied PersistentVolumeClaim pops up.


Example PersistentVolume

In order to find how to specify things you're best advised to take a look at the API for your Kubernetes version, so the following example is build from the API-Reference of K8S 1.17:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: ckan-pv-home
  labels:
    type: local
spec:
  capacity:
    storage: 100Mi
  hostPath:
    path: "/mnt/data/ckan"

The PersistentVolumeSpec allows us to define multiple attributes. I chose a hostPath volume which maps a local directory as content for the volume. The capacity allows the resource scheduler to recognize this volume as applicable in terms of resource needs.


Additional Resources:

Post request in Laravel - Error - 419 Sorry, your session/ 419 your page has expired

This is because the form requires a csrf. In version 5.7, they changed it to @csrf

<form action="" method="post">
    @csrf
    ...

Referene: https://laravel.com/docs/5.7/csrf

Java 11 package javax.xml.bind does not exist

According to the release-notes, Java 11 removed the Java EE modules:

java.xml.bind (JAXB) - REMOVED
  • Java 8 - OK
  • Java 9 - DEPRECATED
  • Java 10 - DEPRECATED
  • Java 11 - REMOVED

See JEP 320 for more info.

You can fix the issue by using alternate versions of the Java EE technologies. Simply add Maven dependencies that contain the classes you need:

<dependency>
  <groupId>javax.xml.bind</groupId>
  <artifactId>jaxb-api</artifactId>
  <version>2.3.0</version>
</dependency>
<dependency>
  <groupId>com.sun.xml.bind</groupId>
  <artifactId>jaxb-core</artifactId>
  <version>2.3.0</version>
</dependency>
<dependency>
  <groupId>com.sun.xml.bind</groupId>
  <artifactId>jaxb-impl</artifactId>
  <version>2.3.0</version>
</dependency>

Jakarta EE 8 update (Mar 2020)

Instead of using old JAXB modules you can fix the issue by using Jakarta XML Binding from Jakarta EE 8:

<dependency>
  <groupId>jakarta.xml.bind</groupId>
  <artifactId>jakarta.xml.bind-api</artifactId>
  <version>2.3.3</version>
</dependency>
<dependency>
  <groupId>com.sun.xml.bind</groupId>
  <artifactId>jaxb-impl</artifactId>
  <version>2.3.3</version>
  <scope>runtime</scope>
</dependency>

Jakarta EE 9 update (Nov 2020)

Use latest release of Eclipse Implementation of JAXB 3.0.0:

<dependency>
  <groupId>jakarta.xml.bind</groupId>
  <artifactId>jakarta.xml.bind-api</artifactId>
  <version>3.0.0</version>
</dependency>
<dependency>
  <groupId>com.sun.xml.bind</groupId>
  <artifactId>jaxb-impl</artifactId>
  <version>3.0.0</version>
  <scope>runtime</scope>
</dependency>

Note: Jakarta EE 9 adopts new API package namespace jakarta.xml.bind.*, so update import statements:

javax.xml.bind -> jakarta.xml.bind

WARNING: API 'variant.getJavaCompile()' is obsolete and has been replaced with 'variant.getJavaCompileProvider()'

if I remove this row from application gradle:

apply plugin: 'io.fabric'

error will not appear anymore.

Reference link github

Objects are not valid as a React child. If you meant to render a collection of children, use an array instead

I also occured the error,and I sloved it by removing the curly braces,hope it will help someone else.

You can see that ,I did not put the con in the curly brace,and the error occured ,when I remove the burly brace , the error disappeared.

const modal = (props) => {
const { show, onClose } = props;

let con = <div className="modal" onClick={onClose}>
        {props.children}
        </div>;

return show === true ? (
    {con}
) : (
    <div>hello</div>
);

There are an article about the usage of the curly brace.click here

Xcode 10: A valid provisioning profile for this executable was not found

Open Keychain Access on your Mac and delete the old expired Apple Development certificates. This solved the issue for me.

Center content vertically on Vuetify

Still surprised that no one proposed the shortest solution with align-center justify-center to center content vertically and horizontally. Check this CodeSandbox and code below:

<v-container fluid fill-height>
  <v-layout align-center justify-center>
    <v-flex>
      <!-- Some HTML elements... -->
    </v-flex>
  </v-layout>
</v-container>

I can't install pyaudio on Windows? How to solve "error: Microsoft Visual C++ 14.0 is required."?

The problem is pyaudio does not have wheels for python 3.7 just try some lower version like 3.6 then install pyaudio

It works

Support for the experimental syntax 'classProperties' isn't currently enabled

I faced the same issue while trying to transpile some jsx with babel. Below is the solution that worked for me. You can add the following json to your .babelrc

{
  "presets": [
    [
      "@babel/preset-react",
      { "targets": { "browsers": ["last 3 versions", "safari >= 6"] } }
    ]
  ],
  "plugins": [["@babel/plugin-proposal-class-properties"]]
}

How can I add shadow to the widget in flutter?

Check out BoxShadow and BoxDecoration

A Container can take a BoxDecoration (going off of the code you had originally posted) which takes a boxShadow

return Container(
  margin: EdgeInsets.only(left: 30, top: 100, right: 30, bottom: 50),
  height: double.infinity,
  width: double.infinity,
  decoration: BoxDecoration(
    color: Colors.white,
    borderRadius: BorderRadius.only(
      topLeft: Radius.circular(10),
        topRight: Radius.circular(10),
        bottomLeft: Radius.circular(10),
        bottomRight: Radius.circular(10)
    ),
    boxShadow: [
      BoxShadow(
        color: Colors.grey.withOpacity(0.5),
        spreadRadius: 5,
        blurRadius: 7,
        offset: Offset(0, 3), // changes position of shadow
      ),
    ],
  ),
)

Screenshot

enter image description here

DeprecationWarning: Buffer() is deprecated due to security and usability issues when I move my script to another server

new Buffer(number)            // Old
Buffer.alloc(number)          // New

new Buffer(string)            // Old
Buffer.from(string)           // New

new Buffer(string, encoding)  // Old
Buffer.from(string, encoding) // New

new Buffer(...arguments)      // Old
Buffer.from(...arguments)     // New

Note that Buffer.alloc() is also faster on the current Node.js versions than new Buffer(size).fill(0), which is what you would otherwise need to ensure zero-filling.

Flutter - The method was called on null

The reason for this error occurs is that you are using the CryptoListPresenter _presenter without initializing.

I found that CryptoListPresenter _presenter would have to be initialized to fix because _presenter.loadCurrencies() is passing through a null variable at the time of instantiation;

there are two ways to initialize

  1. Can be initialized during an declaration, like this

    CryptoListPresenter _presenter = CryptoListPresenter();
    
  2. In the second, initializing(with assigning some value) it when initState is called, which the framework will call this method once for each state object.

    @override
    void initState() {
      _presenter = CryptoListPresenter(...);
    }
    

Can I use library that used android support with Androidx projects.

Add the lines in the gradle.properties file

android.useAndroidX=true
android.enableJetifier=true

enter image description here enter image description here Refer also https://developer.android.com/jetpack/androidx

What is the Record type in typescript?

A Record lets you create a new type from a Union. The values in the Union are used as attributes of the new type.

For example, say I have a Union like this:

type CatNames = "miffy" | "boris" | "mordred";

Now I want to create an object that contains information about all the cats, I can create a new type using the values in the CatName Union as keys.

type CatList = Record<CatNames, {age: number}>

If I want to satisfy this CatList, I must create an object like this:

const cats:CatList = {
  miffy: { age:99 },
  boris: { age:16 },
  mordred: { age:600 }
}

You get very strong type safety:

  • If I forget a cat, I get an error.
  • If I add a cat that's not allowed, I get an error.
  • If I later change CatNames, I get an error. This is especially useful because CatNames is likely imported from another file, and likely used in many places.

Real-world React example.

I used this recently to create a Status component. The component would receive a status prop, and then render an icon. I've simplified the code quite a lot here for illustrative purposes

I had a union like this:

type Statuses = "failed" | "complete";

I used this to create an object like this:

const icons: Record<
  Statuses,
  { iconType: IconTypes; iconColor: IconColors }
> = {
  failed: {
    iconType: "warning",
    iconColor: "red"
  },
  complete: {
    iconType: "check",
    iconColor: "green"
  };

I could then render by destructuring an element from the object into props, like so:

const Status = ({status}) => <Icon {...icons[status]} />

If the Statuses union is later extended or changed, I know my Status component will fail to compile and I'll get an error that I can fix immediately. This allows me to add additional error states to the app.

Note that the actual app had dozens of error states that were referenced in multiple places, so this type safety was extremely useful.

Flutter- wrapping text

Container(
  color: Color.fromRGBO(224, 251, 253, 1.0),
  child: ListTile(
    dense: true,
    title: Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: <Widget>[
        RichText(
          textAlign: TextAlign.left,
          softWrap: true,
          text: TextSpan(children: <TextSpan>
          [
            TextSpan(text: "hello: ",
                style: TextStyle(
                    color: Colors.black, fontWeight: FontWeight.bold)),
            TextSpan(text: "I hope this helps",
                style: TextStyle(color: Colors.black)),
          ]
          ),
        ),
      ],
    ),
  ),
),

Android Material and appcompat Manifest merger failed

just add these two lines of code to your Manifest file

tools:replace="android:appComponentFactory"
android:appComponentFactory="whateverString"

How to scroll page in flutter

Two way to add Scroll in page

1. Using SingleChildScrollView :

     SingleChildScrollView(
          child: Column(
            children: [
              Container(....),
              SizedBox(...),
              Container(...),
              Text(....)
            ],
          ),
      ),

2. Using ListView : ListView is default provide Scroll no need to add extra widget for scrolling

     ListView(
          children: [
            Container(..),
            SizedBox(..),
            Container(...),
            Text(..)
          ],
      ),

Under which circumstances textAlign property works in Flutter?

For maximum flexibility, I usually prefer working with SizedBox like this:

Row(
                                children: <Widget>[
                                  SizedBox(
                                      width: 235,
                                      child: Text('Hey, ')),
                                  SizedBox(
                                      width: 110,
                                      child: Text('how are'),
                                  SizedBox(
                                      width: 10,
                                      child: Text('you?'))
                                ],
                              )

I've experienced problems with text alignment when using alignment in the past, whereas sizedbox always does the work.

Deprecated Gradle features were used in this build, making it incompatible with Gradle 5.0

The process below worked in my case- First check Gradle Version:

cd android
./gradlew -v

In my case it was 6.5

Go to https://developer.android.com/studio/releases/gradle-plugin and you'll get the plugin version for your gradle version. For gradle version 6.5, the plugin version is 4.1.0

Then go to app/build.gradle and change classpath 'com.android.tools.build:gradle:<plugin_version>

Confirm password validation in Angular 6

I am using angular 6 and I have been searching on best way to match password and confirm password. This can also be used to match any two inputs in a form. I used Angular Directives. I have been wanting to use them

ng g d compare-validators --spec false and i will be added in your module. Below is the directive

import { Directive, Input } from '@angular/core';
import { Validator, NG_VALIDATORS, AbstractControl, ValidationErrors } from '@angular/forms';
import { Subscription } from 'rxjs';

@Directive({
  // tslint:disable-next-line:directive-selector
  selector: '[compare]',
  providers: [{ provide: NG_VALIDATORS, useExisting: CompareValidatorDirective, multi: true}]
})
export class CompareValidatorDirective implements Validator {
  // tslint:disable-next-line:no-input-rename
  @Input('compare') controlNameToCompare;

  validate(c: AbstractControl): ValidationErrors | null {
    if (c.value.length < 6 || c.value === null) {
      return null;
    }
    const controlToCompare = c.root.get(this.controlNameToCompare);

    if (controlToCompare) {
      const subscription: Subscription = controlToCompare.valueChanges.subscribe(() => {
        c.updateValueAndValidity();
        subscription.unsubscribe();
      });
    }

    return controlToCompare && controlToCompare.value !== c.value ? {'compare': true } : null;
  }

}

Now in your component

<div class="col-md-6">
              <div class="form-group">
                <label class="bmd-label-floating">Password</label>
                <input type="password" class="form-control" formControlName="usrpass" [ngClass]="{ 'is-invalid': submitAttempt && f.usrpass.errors }">
                <div *ngIf="submitAttempt && signupForm.controls['usrpass'].errors" class="invalid-feedback">
                  <div *ngIf="signupForm.controls['usrpass'].errors.required">Your password is required</div>
                  <div *ngIf="signupForm.controls['usrpass'].errors.minlength">Password must be at least 6 characters</div>
                </div>
              </div>
            </div>
            <div class="col-md-6">
              <div class="form-group">
                <label class="bmd-label-floating">Confirm Password</label>
                <input type="password" class="form-control" formControlName="confirmpass" compare = "usrpass"
                [ngClass]="{ 'is-invalid': submitAttempt && f.confirmpass.errors }">
                <div *ngIf="submitAttempt && signupForm.controls['confirmpass'].errors" class="invalid-feedback">
                  <div *ngIf="signupForm.controls['confirmpass'].errors.required">Your confirm password is required</div>
                  <div *ngIf="signupForm.controls['confirmpass'].errors.minlength">Password must be at least 6 characters</div>
                  <div *ngIf="signupForm.controls['confirmpass'].errors['compare']">Confirm password and Password dont match</div>
                </div>
              </div>
            </div>

I hope this one helps

How to format DateTime in Flutter , How to get current time in flutter?

Here's my simple solution. That does not require any dependency.

However, the date will be in string format. If you want the time then change the substring values

print(new DateTime.now()
            .toString()
            .substring(0,10)
     );   // 2020-06-10

Flutter : Vertically center column

Try:

Column(
 mainAxisAlignment: MainAxisAlignment.center,
 crossAxisAlignment: CrossAxisAlignment.center,
 children:children...)

Angular 6: saving data to local storage

you can use localStorage for storing the json data:

the example is given below:-

let JSONDatas = [
    {"id": "Open"},
    {"id": "OpenNew", "label": "Open New"},
    {"id": "ZoomIn", "label": "Zoom In"},
    {"id": "ZoomOut", "label": "Zoom Out"},
    {"id": "Find", "label": "Find..."},
    {"id": "FindAgain", "label": "Find Again"},
    {"id": "Copy"},
    {"id": "CopyAgain", "label": "Copy Again"},
    {"id": "CopySVG", "label": "Copy SVG"},
    {"id": "ViewSVG", "label": "View SVG"}
]

localStorage.setItem("datas", JSON.stringify(JSONDatas));

let data = JSON.parse(localStorage.getItem("datas"));

console.log(data);

How to use mouseover and mouseout in Angular 6

<div (mouseenter)="changeText=true" (mouseout)="changeText=false">
  <span *ngIf="!changeText">Hide</span>
  <span *ngIf="changeText">Show</span>
</div>

and if you want to use in *ngFor then assign the object value of hover data and then check its id and show hover info/icon or anything like that:-

 <div (mouseenter)="hoverCard(d)" (mouseleave)="hoverCard(null)" *ngFor="let d of data" class="col-lg-3 col-md-4 col-sm-6 mt-4">
   <a *ngIf="hoverData && hoverData.id == d.id" class="text-right"><i class="fas fa-edit"></i>Hover Text</a>
    Normal Text
  </div>

in TS File

  hoverData!:Data|null;

  hoverCard(d: Data|null){
    this.hoverData = sCatg;
  }

How can I add raw data body to an axios request?

axios({
  method: 'post',     //put
  url: url,
  headers: {'Authorization': 'Bearer'+token}, 
  data: {
     firstName: 'Keshav', // This is the body part
     lastName: 'Gera'
  }
});

How do you change the value inside of a textfield flutter?

_mytexteditingcontroller.value = new TextEditingController.fromValue(new TextEditingValue(text: "My String")).value;

This seems to work if anyone has a better way please feel free to let me know.

FirebaseInstanceIdService is deprecated

Kotlin allows for even simpler code than what's shown in other answers.

To get the new token whenever it's refreshed:

class MyFirebaseMessagingService: FirebaseMessagingService() {

    override fun onNewToken(token: String?) {
        Log.d("FMS_TOKEN", token)
    }
    ...
}

To get the token from anywhere at runtime:

FirebaseInstanceId.getInstance().instanceId.addOnSuccessListener {
    Log.d("FMS_TOKEN", it.token)
}

Everytime I run gulp anything, I get a assertion error. - Task function must be specified

https://fettblog.eu/gulp-4-parallel-and-series/

Because gulp.task(name, deps, func) was replaced by gulp.task(name, gulp.{series|parallel}(deps, func)).

You are using the latest version of gulp but older code. Modify the code or downgrade.

Conda version pip install -r requirements.txt --target ./lib

To create an environment named py37 with python 3.7, using the channel conda-forge and a list of packages:

conda create -y --name py37 python=3.7
conda install --force-reinstall -y -q --name py37 -c conda-forge --file requirements.txt
conda activate py37
...
conda deactivate

Flags explained:

  • -y: Do not ask for confirmation.
  • --force-reinstall: Install the package even if it already exists.
  • -q: Do not display progress bar.
  • -c: Additional channel to search for packages. These are URLs searched in the order

The ansible-role dockpack.base_miniconda can manage conda environments and can be used to create a docker base image.

Alternatively you can create an environment.yml file instead of requirements.txt:

name: py37
channels:
  - conda-forge
dependencies:
  - python=3.7
  - numpy=1.9.*
  - pandas

Use this command to list the environments you have:

conda info --envs

Use this command to remove the environment:

conda env remove -n py37

Enable CORS in fetch api

Browser have cross domain security at client side which verify that server allowed to fetch data from your domain. If Access-Control-Allow-Origin not available in response header, browser disallow to use response in your JavaScript code and throw exception at network level. You need to configure cors at your server side.

You can fetch request using mode: 'cors'. In this situation browser will not throw execption for cross domain, but browser will not give response in your javascript function.

So in both condition you need to configure cors in your server or you need to use custom proxy server.

TypeError: only integer scalar arrays can be converted to a scalar index with 1D numpy indices array

Another case that could cause this error is

>>> np.ndindex(np.random.rand(60,60))
TypeError: only integer scalar arrays can be converted to a scalar index

Using the actual shape will fix it.

>>> np.ndindex(np.random.rand(60,60).shape)
<numpy.ndindex object at 0x000001B887A98880>

Google Maps shows "For development purposes only"

For me, Error has been fixed when activated Billing in google console. (I got 1-year developer trial)

Pytesseract : "TesseractNotFound Error: tesseract is not installed or it's not in your path", how do I fix this?

you can install this package... https://github.com/UB-Mannheim/tesseract/wiki after that you should go this path C:\Program Files (x86)\Tesseract-OCR\ tesseract.exe then run tesseract file. I think this will help you...

How to add image in Flutter

How to include images in your app

1. Create an assets/images folder

  • This should be located in the root of your project, in the same folder as your pubspec.yaml file.
  • In Android Studio you can right click in the Project view
  • You don't have to call it assets or images. You don't even need to make images a subfolder. Whatever name you use, though, is what you will regester in the pubspec.yaml file.

2. Add your image to the new folder

  • You can just copy your image into assets/images. The relative path of lake.jpg, for example, would be assets/images/lake.jpg.

3. Register the assets folder in pubspec.yaml

  • Open the pubspec.yaml file that is in the root of your project.

  • Add an assets subsection to the flutter section like this:

      flutter:
        assets:
          - assets/images/lake.jpg
    
  • If you have multiple images that you want to include then you can leave off the file name and just use the directory name (include the final /):

      flutter:
        assets:
          - assets/images/
    

4. Use the image in code

  • Get the asset in an Image widget with Image.asset('assets/images/lake.jpg').

  • The entire main.dart file is here:

      import 'package:flutter/material.dart';
    
      void main() => runApp(MyApp());
    
      class MyApp extends StatelessWidget {
        @override
        Widget build(BuildContext context) {
          return MaterialApp(
            home: Scaffold(
              appBar: AppBar(
                title: Text("Image from assets"),
              ),
              body: Image.asset('assets/images/lake.jpg'), //   <--- image
            ),
          );
        }
      }
    

5. Restart your app

When making changes to pubspec.yaml I find that I often need to completely stop my app and restart it again, especially when adding assets. Otherwise I get a crash.

Running the app now you should have something like this:

enter image description here

Further reading

  • See the documentation for how to do things like provide alternate images for different densities.

Videos

The first video here goes into a lot of detail about how to include images in your app. The second video covers more about how to adjust how they look.

Flutter position stack widget in center

A Stack allows you to stack elements on top of each other, with the last element in the array taking the highest priority. You can use Align, Positioned, or Container to position the children of a stack.

Align

Widgets are moved by setting the alignment with Alignment, which has static properties like topCenter, bottomRight, and so on. Or you can take full control and set Alignment(1.0, -1.0), which takes x,y values ranging from 1.0 to -1.0, with (0,0) being the center of the screen.

  Stack(
      children: [
        Align(
          alignment: Alignment.topCenter,
          child: Container(
              height: 80,
              width: 80, color: Colors.blueAccent
          ),
        ),
        Align(
          alignment: Alignment.center,
          child: Container(
              height: 80,
              width: 80, color: Colors.deepPurple
          ),
        ),
        Container(
          alignment: Alignment.bottomCenter,
          // alignment: Alignment(1.0, -1.0),
          child: Container(
              height: 80,
              width: 80, color: Colors.amber
          ),
        )
      ]
  )

enter image description here

Angular 6: How to set response type as text while making http call

Use like below:

  yourFunc(input: any):Observable<string> {
var requestHeader = { headers: new HttpHeaders({ 'Content-Type': 'text/plain', 'No-Auth': 'False' })};
const headers = new HttpHeaders().set('Content-Type', 'text/plain; charset=utf-8');
return this.http.post<string>(this.yourBaseApi+ '/do-api', input, { headers, responseType: 'text' as 'json'  });

}

Android design support library for API 28 (P) not working

I cross that situation by replacing all androidx.* to appropiate package name.

change your line

implementation 'androidx.appcompat:appcompat:1.0.0-alpha3'
implementation 'androidx.constraintlayout:constraintlayout:1.1.1'

androidTestImplementation 'androidx.test:runner:1.1.0-alpha3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0-alpha3'

to

implementation 'com.android.support:appcompat-v7:28.0.0-alpha3'
implementation 'com.android.support.constraint:constraint-layout:1.1.1'

androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

NOTED

  • remove tools:replace="android:appComponentFactory" from AndroidManifest

react button onClick redirect page

I was also having the trouble to route to a different view using navlink.

My implementation was as follows and works perfectly;

<NavLink tag='li'>
  <div
    onClick={() =>
      this.props.history.push('/admin/my- settings')
    }
  >
    <DropdownItem className='nav-item'>
      Settings
    </DropdownItem>
  </div>
</NavLink>

Wrap it with a div, assign the onClick handler to the div. Use the history object to push a new view.

Dart/Flutter : Converting timestamp

I don't know if this will help anyone. The previous messages have helped me so I'm here to suggest a few things:

import 'package:intl/intl.dart';

    DateTime convertTimeStampToDateTime(int timeStamp) {
     var dateToTimeStamp = DateTime.fromMillisecondsSinceEpoch(timeStamp * 1000);
     return dateToTimeStamp;
   }

  String convertTimeStampToHumanDate(int timeStamp) {
    var dateToTimeStamp = DateTime.fromMillisecondsSinceEpoch(timeStamp * 1000);
    return DateFormat('dd/MM/yyyy').format(dateToTimeStamp);
  }

   String convertTimeStampToHumanHour(int timeStamp) {
     var dateToTimeStamp = DateTime.fromMillisecondsSinceEpoch(timeStamp * 1000);
     return DateFormat('HH:mm').format(dateToTimeStamp);
   }

   int constructDateAndHourRdvToTimeStamp(DateTime dateTime, TimeOfDay time ) {
     final constructDateTimeRdv = dateTimeToTimeStamp(DateTime(dateTime.year, dateTime.month, dateTime.day, time.hour, time.minute)) ;
     return constructDateTimeRdv;
   }

Failed to resolve: com.google.firebase:firebase-core:16.0.1

Add maven { url "https://maven.google.com" } to your root level build.gradle file

repositories {
    maven { url "https://maven.google.com" }
    flatDir {
        dirs 'libs'
    }
}

How do I center text vertically and horizontally in Flutter?

You can use TextAlign property of Text constructor.

Text("text", textAlign: TextAlign.center,)

Iterating through a list to render multiple widgets in Flutter?

All you need to do is put it in a list and then add it as the children of the widget.

you can do something like this:

Widget listOfWidgets(List<String> item) {
  List<Widget> list = List<Widget>();
  for (var i = 0; i < item.length; i++) {
    list.add(Container(
        child: FittedBox(
          fit: BoxFit.fitWidth,
          child: Text(
            item[i],
          ),
        )));
  }
  return Wrap(
      spacing: 5.0, // gap between adjacent chips
      runSpacing: 2.0, // gap between lines
      children: list);
}

After that call like this

child: Row(children: <Widget>[
   listOfWidgets(itemList),
])

enter image description here

Can not find module “@angular-devkit/build-angular”

I tried all the possible commands listed above and none of them worked for me, Check if Package.json contain "@angular-devkit/build-angular" if not just install it using(in my case version 0.803.19 worked)

npm i @angular-devkit/[email protected]

Or checkout at npm website repositories for version selection

How to change TextField's height and width?

You can try the margin property in the Container. Wrap the TextField inside a Container and adjust the margin property.

new Container(
  margin: const EdgeInsets.only(right: 10, left: 10),
  child: new TextField( 
    decoration: new InputDecoration(
      hintText: 'username',
      icon: new Icon(Icons.person)),
  )
),

How to resolve Unable to load authentication plugin 'caching_sha2_password' issue

remove the connect .jar file if you added the multiple version connector jar file only add the connector jar file that match with your sql version.

Could not find module "@angular-devkit/build-angular"

I faced the same problem.

Surprisingly, it was just because the version specified in package.json was not in the expected format.

I switched from version "version": "0.1" to "version": "0.0.1" and it solved the problem.

Angular NEEDS semantic versioning (also read Semver) with three parts.

How to set the width of a RaisedButton in Flutter?

Wrap RaisedButton inside Container and give width to Container Widget.

e.g

 Container(
 width : 200,
 child : RaisedButton(
         child :YourWidget ,
         onPressed(){}
      ),
    )

HTTP POST with Json on Body - Flutter/Dart

I implement like this:

static createUserWithEmail(String username, String email, String password) async{
    var url = 'http://www.yourbackend.com/'+ "users";
    var body = {
        'user' : {
          'username': username,
          'address': email,
          'password': password
       }
    };

    return http.post(
      url, 
      body: json.encode(body),
      headers: {
        "Content-Type": "application/json"
      },
      encoding: Encoding.getByName("utf-8")
    );
  }

ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean

Apart from the possible solutions in other answers, it is also possible that somehow Maven dependency corruption has occurred on your machine. I was facing the same error on trying to run my (Web) Spring boot application, and it got resolved by running the following -

mvn dependency:purge-local-repository -DreResolve=true

followed by

mvn package

I came onto this solution looking into another issue where Eclipse wouldn't let me run the main application class from the IDE, due to a different error, similar to one on this SO thread -> The type org.springframework.context.ConfigurableApplicationContext cannot be resolved. It is indirectly referenced from required .class files

MongoNetworkError: failed to connect to server [localhost:27017] on first connect [MongoNetworkError: connect ECONNREFUSED 127.0.0.1:27017]

This worked for me.

mongoose.Promise = global.Promise;
  .connect(
    "mongodb://127.0.0.1:27017/mydb",
    { useNewUrlParser: true, useCreateIndex: true, useUnifiedTopology: true}).then(db => {
      console.log("Database connected");
    }).catch(error => console.log("Could not connect to mongo db " + error));

I was using localhost, so i changed it to:

mongodb://127.0.0.1:27017/mydb

Not able to change TextField Border Color

enabledBorder: OutlineInputBorder(
  borderRadius: BorderRadius.circular(10.0),
  borderSide: BorderSide(color: Colors.red)
),

MySQL 8.0 - Client does not support authentication protocol requested by server; consider upgrading MySQL client

I just run into this problem too, with all the MySQL re-config mentioned above the error still appears. It turns out that I misspelled the database name.

So be sure you're connecting with the right database name especially the case.

Create a button with rounded border

If you don't want to use OutlineButton and want to stick to normal RaisedButton, you can wrap your button in ClipRRect or ClipOval like:

ClipRRect(
  borderRadius: BorderRadius.circular(40),
  child: RaisedButton(
    child: Text("Button"),
    onPressed: () {},
  ),
),

Button Width Match Parent

you can do that wit MaterialButton

MaterialButton(
     padding: EdgeInsets.all(12.0),
     minWidth: double.infinity,
     onPressed: () {},
    child: Text("Btn"),
)

flutter corner radius with transparent background

If you want to round corners with transparent background, the best approach is using ClipRRect.

return ClipRRect(
  borderRadius: BorderRadius.circular(40.0),
  child: Container(
    height: 800.0,
    width: double.infinity,
    color: Colors.blue,
    child: Center(
      child: new Text("Hi modal sheet"),
    ),
  ),
);

Set focus on <input> element

You should use html autofocus for this:

<input *ngIf="show" #search type="text" autofocus /> 

Note: if your component is persisted and reused it will only autofocus the first time the fragment is attached. This can be overcome by having a global dom listener that checks for autofocus attribute inside a dom fragment when it is attached and then reapplying it or focus via javascript.

Axios handling errors

You can go like this: error.response.data
In my case, I got error property from backend. So, I used error.response.data.error

My code:

axios
  .get(`${API_BASE_URL}/students`)
  .then(response => {
     return response.data
  })
  .then(data => {
     console.log(data)
  })
  .catch(error => {
     console.log(error.response.data.error)
  })

Error: Local workspace file ('angular.json') could not be found

Check your folder structure where you are executing the command, you should run the command 'ng serve' where there should be a angular.json file in the structure.

angular.json file will be generated by default when we run the command

npm install -g '@angular/cli' ng new Project_name then cd project_folder then, run ng serve. it worked for me

How to make flutter app responsive according to different screen size?

Place dependency in pubspec.yaml

flutter_responsive_screen: ^1.0.0

Function hp = Screen(MediaQuery.of(context).size).hp;
Function wp = Screen(MediaQuery.of(context).size).wp;

Example :
return Container(height: hp(27),weight: wp(27));

Extract Google Drive zip from Google colab notebook

Colab research team has a notebook for helping you out.

Still, in short, if you are dealing with a zip file, like for me it is mostly thousands of images and I want to store them in a folder within drive then do this --

!unzip -u "/content/drive/My Drive/folder/example.zip" -d "/content/drive/My Drive/folder/NewFolder"

-u part controls extraction only if new/necessary. It is important if suddenly you lose connection or hardware switches off.

-d creates the directory and extracted files are stored there.

Of course before doing this you need to mount your drive

from google.colab import drive 
drive.mount('/content/drive')

I hope this helps! Cheers!!

Angular 5 ngHide ngShow [hidden] not working

2019 Update: I realize that this is somewhat bad advice. As the first comment states, this heavily depends on the situation, and it is not a bad practice to use the [hidden] attribute: see the comments for some of the cases where you need to use it and not *ngIf

Original answer:

You should always try to use *ngIf instead of [hidden].

 <input *ngIf="!isHidden" class="txt" type="password" [(ngModel)]="input_pw" >

There are several blog posts about that topics, but the bottom line is, that Hidden usually means you do not want the browser to render the object - using angular you still waste resource on rendering it, and it will end up in the DOM anyway (and tricky users can see it with basic browser manipulation).

How to use lifecycle method getDerivedStateFromProps as opposed to componentWillReceiveProps

About the removal of componentWillReceiveProps: you should be able to handle its uses with a combination of getDerivedStateFromProps and componentDidUpdate, see the React blog post for example migrations. And yes, the object returned by getDerivedStateFromProps updates the state similarly to an object passed to setState.

In case you really need the old value of a prop, you can always cache it in your state with something like this:

state = {
  cachedSomeProp: null
  // ... rest of initial state
};

static getDerivedStateFromProps(nextProps, prevState) {
  // do things with nextProps.someProp and prevState.cachedSomeProp
  return {
    cachedSomeProp: nextProps.someProp,
    // ... other derived state properties
  };
}

Anything that doesn't affect the state can be put in componentDidUpdate, and there's even a getSnapshotBeforeUpdate for very low-level stuff.

UPDATE: To get a feel for the new (and old) lifecycle methods, the react-lifecycle-visualizer package may be helpful.

Default interface methods are only supported starting with Android N

This also happened to me but using Dynamic Features. I already had Java 8 compatibility enabled in the app module but I had to add this compatibility lines to the Dynamic Feature module and then it worked.

Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified

I encountered this error simply because I misspelled the spring.datasource.url value in the application.properties file and I was using postgresql:

Problem was: jdbc:postgres://localhost:<port-number>/<database-name>

Fixed to: jdbc:postgresql://localhost:<port-number>/<database-name>

NOTE: the difference is postgres & postgresql, the two are 2 different things.

Further causes and solutions may be found here

Round button with text and icon in flutter

You can simply use named constructors for creating different types of buttons with icons. For instance

FlatButton.icon(onPressed: null, icon: null, label: null);
RaisedButton.icon(onPressed: null, icon: null, label: null);

But if you have specfic requirements then you can always create custom button with different layouts or simply wrap a widget in GestureDetector.

How to implement drop down list in flutter?

place the value inside the items.then it will work,

new DropdownButton<String>(
              items:_dropitems.map((String val){
                return DropdownMenuItem<String>(
                  value: val,
                  child: new Text(val),
                );
              }).toList(),
              hint:Text(_SelectdType),
              onChanged:(String val){
                _SelectdType= val;
                setState(() {});
                })

error: resource android:attr/fontVariationSettings not found

I had the same issue and I installed this cordova plugin and problem solved.

cordova plugin add cordova-android-support-gradle-release --save

Error : Program type already present: android.support.design.widget.CoordinatorLayout$Behavior

As android latest update doesn't support 'compile' keyword use 'implementation' in place inside your module build.gradle file.

And check thoroughly in build.gradle for dependancy with + sign like this.

implementation 'com.android.support:support-v4:28.+'

If there are any dependencies like this, just update them with a specific version. After that:

  1. Sync gradle.
  2. Clean your project.
  3. Rebuild the project.

After Spring Boot 2.0 migration: jdbcUrl is required with driverClassName

I also read the Spring docs, as lapkritinis suggested - and luckily this brought me on the right path! But I don´t think, that the Spring docs explain this good right now. At least for me, they aren´t consistent IMHO.

The original problem/question is on what to do, if you upgrade an existing Spring Boot 1.5.x application to 2.0.x, which is using PostgreSQL/Hibernate. The main reason, you get your described error, is that Spring Boot 2.0.x uses HikariCP instead of Tomcat JDBC pooling DataSource as a default - and Hikari´s DataSource doesn´t know the spring.datasource.url property, instead it want´s to have spring.datasource.jdbc-url (lapkritinis also pointed that out).

So far so good. BUT the docs also suggest - and that´s the problem here - that Spring Boot uses spring.datasource.url to determine, if the - often locally used - embedded Database like H2 has to back off and instead use a production Database:

You should at least specify the URL by setting the spring.datasource.url property. Otherwise, Spring Boot tries to auto-configure an embedded database.

You may see the dilemma. If you want to have your embedded DataBase like you´re used to, you have to switch back to Tomcat JDBC. This is also much more minimally invasive to existing applications, as you don´t have to change source code! To get your existing application working after the Spring Boot 1.5.x --> 2.0.x upgrade with PostgreSQL, just add tomcat-jdbc as a dependency to your pom.xml:

    <dependency>
        <groupId>org.apache.tomcat</groupId>
        <artifactId>tomcat-jdbc</artifactId>
    </dependency>

And then configure Spring Boot to use it accordingly inside application.properties:

spring.datasource.type=org.apache.tomcat.jdbc.pool.DataSource

Hope to help some folks with this, was quite a time consuming problem. I also hope my beloved Spring folks update the docs - and the way new Hikari pool is configured - to get a more consistent Spring Boot user experience :)

Flutter: how to make a TextField with HintText but no Underline?

            Container(
         height: 50,
          // margin: EdgeInsets.only(top: 20),
          decoration: BoxDecoration(
              color: Colors.tealAccent,
              borderRadius: BorderRadius.circular(32)),
          child: TextFormField(
            cursorColor: Colors.black,
            // keyboardType: TextInputType.,
            decoration: InputDecoration(
              hintStyle: TextStyle(fontSize: 17),
              hintText: 'Search your trips',
              suffixIcon: Icon(Icons.search),
              border: InputBorder.none,
              contentPadding: EdgeInsets.all(18),
            ),
          ),
        ),

'ls' is not recognized as an internal or external command, operable program or batch file

If you want to use Unix shell commands on Windows, you can use Windows Powershell, which includes both Windows and Unix commands as aliases. You can find more info on it in the documentation.

PowerShell supports aliases to refer to commands by alternate names. Aliasing allows users with experience in other shells to use common command names that they already know for similar operations in PowerShell.

The PowerShell equivalents may not produce identical results. However, the results are close enough that users can do work without knowing the PowerShell command name.

How to render string with html tags in Angular 4+?

Use one way flow syntax property binding:

<div [innerHTML]="comment"></div>

From angular docs: "Angular recognizes the value as unsafe and automatically sanitizes it, which removes the <script> tag but keeps safe content such as the <b> element."

How to create a new text file using Python

# Method 1
f = open("Path/To/Your/File.txt", "w")   # 'r' for reading and 'w' for writing
f.write("Hello World from " + f.name)    # Write inside file 
f.close()                                # Close file 

# Method 2
with open("Path/To/Your/File.txt", "w") as f:   # Opens file and casts as f 
    f.write("Hello World form " + f.name)       # Writing
    # File closed automatically

There are many more methods but these two are most common. Hope this helped!

VSCode single to double quote automatic replace

For projects that use .editorconfig file by default. The formatter will ignore the rules in the settings and use the rules in .editorconfig, then you can either:

  • Remove .editorconfig file, and use your VSCode settings.
  • Add quote_type = single to the .editorconfig file regarding your file type. You can also set quote_type value to double or auto.

js 'types' can only be used in a .ts file - Visual Studio Code using @ts-check

For anyone who lands here and all the other solutions did not work give this a try. I am using typescript + react and my problem was that I was associating the files in vscode as javascriptreact not typescriptreact so check your settings for the following entries.

   "files.associations": {
    "*.tsx": "typescriptreact",
    "*.ts": "typescriptreact"
  },

Entity Framework Core: A second operation started on this context before a previous operation completed

I faced the same issue but the reason was none of the ones listed above. I created a task, created a scope inside the task and asked the container to obtain a service. That worked fine but then I used a second service inside the task and I forgot to also asked for it to the new scope. Because of that, the 2nd service was using a DbContext that was already disposed.

Task task = Task.Run(() =>
    {
        using (var scope = serviceScopeFactory.CreateScope())
        {
            var otherOfferService = scope.ServiceProvider.GetService<IOfferService>();
            // everything was ok here. then I did: 
            productService.DoSomething(); // (from the main scope) and this failed because the db context associated to that service was already disposed.
            ...
        }
    }

I should have done this:

var otherProductService = scope.ServiceProvider.GetService<IProductService>();
otherProductService.DoSomething();

Reading images in python

I read all answers but I think one of the best method is using openCV library.

import cv2

img = cv2.imread('your_image.png',0)

and for displaying the image, use the following code :

from matplotlib import pyplot as plt
plt.imshow(img, cmap = 'gray', interpolation = 'bicubic')
plt.xticks([]), plt.yticks([])  # to hide tick values on X and Y axis
plt.show()

How can I clear the terminal in Visual Studio Code?

F1 key opens the shortcuts for me using windows 10. Then type Terminal and you see the clear option.

Failed linking file resources

You maybe having this error on your java files because there is one or more XML file with error.

Go through all your XML files and resolve errors, then clean or rebuild project from build menu

Start with your most recent edited XML file

ReactJS: Maximum update depth exceeded error

ReactJS: Maximum update depth exceeded error

inputDigit(digit){
  this.setState({
    displayValue: String(digit)
  })

<button type="button"onClick={this.inputDigit(0)}>

why that?

<button type="button"onClick={() => this.inputDigit(1)}>1</button>

The function onDigit sets the state, which causes a rerender, which causes onDigit to fire because that’s the value you’re setting as onClick which causes the state to be set which causes a rerender, which causes onDigit to fire because that’s the value you’re… Etc

How to Set/Update State of StatefulWidget from other StatefulWidget in Flutter?

Old one but I would add my answer as per my findings:

var ancestralState = context.findAncestorStateOfType<ParentState>();
      ancestralState.setState(() {
        // here you can access public vars and update state.
        ...
      });

Not able to pip install pickle in python 3.6

pickle module is part of the standard library in Python for a very long time now so there is no need to install it via pip. I wonder if you IDE or command line is not messed up somehow so that it does not find python installation path. Please check if your %PATH% contains a path to python (e.g. C:\Python36\ or something similar) or if your IDE correctly detects root path where Python is installed.

Functions are not valid as a React child. This may happen if you return a Component instead of from render

In my case i forgot to add the () after the function name inside the render function of a react component

public render() {
       let ctrl = (
           <>
                <div className="aaa">
                    {this.renderView}
                </div>
            </>
       ); 

       return ctrl;
    };


    private renderView() : JSX.Element {
        // some html
    };

Changing the render method, as it states in the error message to

        <div className="aaa">
            {this.renderView()}
        </div>

fixed the problem

Google Colab: how to read data from my google drive?

You can simply make use of the code snippets on the left of the screen. enter image description here

Insert "Mounting Google Drive in your VM"

run the code and copy&paste the code in the URL

and then use !ls to check the directories

!ls /gdrive

for most cases, you will find what you want in the directory "/gdrive/My drive"

then you may carry it out like this:

from google.colab import drive
drive.mount('/gdrive')
import glob

file_path = glob.glob("/gdrive/My Drive/***.txt")
for file in file_path:
    do_something(file)

'' is not recognized as an internal or external command, operable program or batch file

This is a very common question seen on Stackoverflow.

The important part here is not the command displayed in the error, but what the actual error tells you instead.

a Quick breakdown on why this error is received.

cmd.exe Being a terminal window relies on input and system Environment variables, in order to perform what you request it to do. it does NOT know the location of everything and it also does not know when to distinguish between commands or executable names which are separated by whitespace like space and tab or commands with whitespace as switch variables.

How do I fix this:

When Actual Command/executable fails

First we make sure, is the executable actually installed? If yes, continue with the rest, if not, install it first.

If you have any executable which you are attempting to run from cmd.exe then you need to tell cmd.exe where this file is located. There are 2 ways of doing this.

  1. specify the full path to the file.

    "C:\My_Files\mycommand.exe"

  2. Add the location of the file to your environment Variables.

Goto:
------> Control Panel-> System-> Advanced System Settings->Environment Variables

In the System Variables Window, locate path and select edit

Now simply add your path to the end of the string, seperated by a semicolon ; as:

;C:\My_Files\

Save the changes and exit. You need to make sure that ANY cmd.exe windows you had open are then closed and re-opened to allow it to re-import the environment variables. Now you should be able to run mycommand.exe from any path, within cmd.exe as the environment is aware of the path to it.

When C:\Program or Similar fails

This is a very simple error. Each string after a white space is seen as a different command in cmd.exe terminal, you simply have to enclose the entire path in double quotes in order for cmd.exe to see it as a single string, and not separate commands.

So to execute C:\Program Files\My-App\Mobile.exe simply run as:

"C:\Program Files\My-App\Mobile.exe"

Issue in installing php7.2-mcrypt

Mcrypt PECL extenstion

 sudo apt-get -y install gcc make autoconf libc-dev pkg-config
 sudo apt-get -y install libmcrypt-dev
 sudo pecl install mcrypt-1.0.1

When you are shown the prompt

 libmcrypt prefix? [autodetect] :

Press [Enter] to autodetect.

After success installing mcrypt trought pecl, you should add mcrypt.so extension to php.ini.

The output will look like this:

...
Build process completed successfully
Installing '/usr/lib/php/20170718/mcrypt.so'    ---->   this is our path to mcrypt extension lib
install ok: channel://pecl.php.net/mcrypt-1.0.1
configuration option "php_ini" is not set to php.ini location
You should add "extension=mcrypt.so" to php.ini

Grab installing path and add to cli and apache2 php.ini configuration.

sudo bash -c "echo extension=/usr/lib/php/20170718/mcrypt.so > /etc/php/7.2/cli/conf.d/mcrypt.ini"
sudo bash -c "echo extension=/usr/lib/php/20170718/mcrypt.so > /etc/php/7.2/apache2/conf.d/mcrypt.ini"

Verify that the extension was installed

Run command:

php -i | grep "mcrypt"

The output will look like this:

/etc/php/7.2/cli/conf.d/mcrypt.ini
Registered Stream Filters => zlib.*, string.rot13, string.toupper, string.tolower, string.strip_tags, convert.*, consumed, dechunk, convert.iconv.*, mcrypt.*, mdecrypt.*
mcrypt
mcrypt support => enabled
mcrypt_filter support => enabled
mcrypt.algorithms_dir => no value => no value
mcrypt.modes_dir => no value => no value

Error:Cannot fit requested classes in a single dex file.Try supplying a main-dex list. # methods: 72477 > 65536

You can follow this.

Versions of the platform prior to Android 5.0 (API level 21) use the Dalvik runtime for executing app code. By default, Dalvik limits apps to a single classes.dex bytecode file per APK. In order to get around this limitation, you can add the multidex support library to your project:

dependencies {
  implementation 'com.android.support:multidex:1.0.3'
}

If your minSdkVersion is set to 21 or higher, all you need to do is set multiDexEnabled to true in your module-level build.gradle file, as shown here:

android {
    defaultConfig {
        ...
        minSdkVersion 21 
        targetSdkVersion 28
        multiDexEnabled true
    }
    ...
}

Stylesheet not loaded because of MIME-type

This is specific to Typescript+Express

I ctrl+f'd "Typescript" and ".ts" and found nothing in these answers, so I'll add my solution here, since it was caused by (my inexperience with) typescript, and the solutions I've read don't explicit solve this particular issue.

The problem was that Typescript was compiling my app.ts file into a javascript file in my project's dist directory, dist/app.js

Here's my directory structure, see if you can spot the problem:

+-- app.ts
+-- dist
¦   +-- app.js
¦   +-- app.js.map
¦   +-- js
¦       +-- dbclient.js
¦       +-- dbclient.js.map
¦       +-- mutators.js
¦       +-- mutators.js.map
+-- public
¦   +-- css
¦   ¦   +-- styles.css
+-- tsconfig.json
+-- tslint.json
+-- views
    +-- index.hbs
    +-- results.hbs

My problem is that in app.ts, I was telling express to set my public directory as /public, which would be a valid path if Node actually were running Typescript. But Node is running the compiled javascript, app.js, which is in the dist directory.

So having app.ts pretend it's dist/app.js solved my problem. Thus, I fixed the problem in app.ts by changing

app.use(e.static(path.join(__dirname, "/public")));

to

app.use(e.static(path.join(__dirname, "../public")));

Import functions from another js file. Javascript

You can try as follows:

//------ js/functions.js ------
export function square(x) {
    return x * x;
}
export function diag(x, y) {
    return sqrt(square(x) + square(y));
}

//------ js/main.js ------
import { square, diag } from './functions.js';
console.log(square(11)); // 121
console.log(diag(4, 3)); // 5

You can also import completely:

//------ js/main.js ------
import * as lib from './functions.js';
console.log(lib.square(11)); // 121
console.log(lib.diag(4, 3)); // 5

Normally we use ./fileName.js for importing own js file/module and fileName.js is used for importing package/library module

When you will include the main.js file to your webpage you must set the type="module" attribute as follows:

<script type="module" src="js/main.js"></script>

For more details please check ES6 modules

json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 190)

You have two records in your json file, and json.loads() is not able to decode more than one. You need to do it record by record.

See Python json.loads shows ValueError: Extra data

OR you need to reformat your json to contain an array:

{
    "foo" : [
       {"name": "XYZ", "address": "54.7168,94.0215", "country_of_residence": "PQR", "countries": "LMN;PQRST", "date": "28-AUG-2008", "type": null},
       {"name": "OLMS", "address": null, "country_of_residence": null, "countries": "Not identified;No", "date": "23-FEB-2017", "type": null}
    ]
}

would be acceptable again. But there cannot be several top level objects.

Force flex item to span full row width

When you want a flex item to occupy an entire row, set it to width: 100% or flex-basis: 100%, and enable wrap on the container.

The item now consumes all available space. Siblings are forced on to other rows.

_x000D_
_x000D_
.parent {
  display: flex;
  flex-wrap: wrap;
}

#range, #text {
  flex: 1;
}

.error {
  flex: 0 0 100%; /* flex-grow, flex-shrink, flex-basis */
  border: 1px dashed black;
}
_x000D_
<div class="parent">
  <input type="range" id="range">
  <input type="text" id="text">
  <label class="error">Error message (takes full width)</label>
</div>
_x000D_
_x000D_
_x000D_

More info: The initial value of the flex-wrap property is nowrap, which means that all items will line up in a row. MDN

java.lang.IllegalStateException: Only fullscreen opaque activities can request orientation

The only solution that really works :

Change:

<item name="android:windowIsTranslucent">true</item>

to:

<item name="android:windowIsTranslucent">false</item>

in styles.xml

But this might induce a problem with your splashscreen (white screen at startup)... In this case, add the following line to your styles.xml:

 <item name="android:windowDisablePreview">true</item> 

just below the windowIsTranslucent line.

Last chance if the previous tips do not work : target SDK 26 instead o 27.

Execution failed for task ':app:compileDebugJavaWithJavac' Android Studio 3.1 Update

I found the solution as Its problem with Android Studio 3.1 Canary 6

My backup of Android Studio 3.1 Canary 5 is useful to me and saved my half day.

Now My build.gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
    buildToolsVersion '27.0.2'
    defaultConfig {
        applicationId "com.example.demo"
        minSdkVersion 15
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        vectorDrawables.useSupportLibrary = true
    }
    dataBinding {
        enabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    productFlavors {
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.android.support:design:${rootProject.ext.supportLibVersion}"
    implementation "com.android.support:support-v4:${rootProject.ext.supportLibVersion}"
    implementation "com.android.support:recyclerview-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.android.support:cardview-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.squareup.retrofit2:retrofit:2.3.0"
    implementation "com.google.code.gson:gson:2.8.2"
    implementation "com.android.support.constraint:constraint-layout:1.0.2"
    implementation "com.squareup.retrofit2:converter-gson:2.3.0"
    implementation "com.squareup.okhttp3:logging-interceptor:3.6.0"
    implementation "com.squareup.picasso:picasso:2.5.2"
    implementation "com.dlazaro66.qrcodereaderview:qrcodereaderview:2.0.3"
    compile 'com.github.elevenetc:badgeview:v1.0.0'
    annotationProcessor 'com.github.elevenetc:badgeview:v1.0.0'
    testImplementation "junit:junit:4.12"
    androidTestImplementation("com.android.support.test.espresso:espresso-core:3.0.1", {
        exclude group: "com.android.support", module: "support-annotations"
    })
}

and My gradle is:

classpath 'com.android.tools.build:gradle:3.1.0-alpha06'

and its working finally.

I think there problem in Android Studio 3.1 Canary 6

Thank you all for your time.

Python: Pandas pd.read_excel giving ImportError: Install xlrd >= 0.9.0 for Excel support

Was getting the error while I was using jupyter.

ModuleNotFoundError: No module named 'xlrd'
...
ImportError: Install xlrd >= 0.9.0 for Excel support

it was resolved for me after using.

!pip install xlrd

'react-scripts' is not recognized as an internal or external command

This is how I fix it

  1. Check and Update the path variable (See below on how to update the path variable)
  2. Delete node_modules and package-lock.json
  3. run npm install
  4. run npm run start

if this didn't work, try to install the nodejs and run repair

or clean npm cache npm cache clean --force

To update the path variable

  1. press windows key
  2. Search for Edit the system environmental variable
  3. Click on Environment Variables...
  4. on System variable bottom section ( there will be two section )
  5. Select Path variable name
  6. Click Edit..
  7. Check if there is C:\Program Files\nodejs on the list, if not add this

How to start up spring-boot application via command line?

A Spring Boot project configured through Maven can be run using the following command from the project source folder

mvn spring-boot:run

Android Studio AVD - Emulator: Process finished with exit code 1

None of the solutions worked for me. I ended up downloading a different emulator image.

First I had arm64-v8a, which was giving this error. I download armeabi-v7a, which worked fine.

Unfortunately I was not able to install HAXM accelerator as organization's softwares were blocking the installation. Hence, had to go with arm.

installing urllib in Python3.6

yu have to install the correct version for your computer 32 or 63 bits thats all

db.collection is not a function when using MongoClient v3.0

I encountered the same thing. In package.json, change mongodb line to "mongodb": "^2.2.33". You will need to npm uninstall mongodb; then npm install to install this version.

This resolved the issue for me. Seems to be a bug or docs need to be updated.

forEach() in React JSX does not output any HTML

You need to pass an array of element to jsx. The problem is that forEach does not return anything (i.e it returns undefined). So it's better to use map because map returns an array:

class QuestionSet extends Component {
render(){ 
    <div className="container">
       <h1>{this.props.question.text}</h1>
       {this.props.question.answers.map((answer, i) => {     
           console.log("Entered");                 
           // Return the element. Also pass key     
           return (<Answer key={answer} answer={answer} />) 
        })}
}

export default QuestionSet;

Is ConfigurationManager.AppSettings available in .NET Core 2.0?

Yes, ConfigurationManager.AppSettings is available in .NET Core 2.0 after referencing NuGet package System.Configuration.ConfigurationManager.

Credits goes to @JeroenMostert for giving me the solution.

Accessing session from TWIG template

A simple trick is to define the $_SESSION array as a global variable. For that, edit the core.php file in the extension folder by adding this function :

public function getGlobals() {
    return array(
        'session'   => $_SESSION,
    ) ;
}

Then, you'll be able to acces any session variable as :

{{ session.username }}

if you want to access to

$_SESSION['username']

CSS get height of screen resolution

You could use viewport-percentage lenghts.

See: http://stanhub.com/how-to-make-div-element-100-height-of-browser-window-using-css-only/

It works like this:

.element{
    height: 100vh; /* For 100% screen height */
    width:  100vw; /* For 100% screen width */
}

More info also available through Mozilla Developer Network and W3C.

How to write trycatch in R

Well then: welcome to the R world ;-)

Here you go

Setting up the code

urls <- c(
    "http://stat.ethz.ch/R-manual/R-devel/library/base/html/connections.html",
    "http://en.wikipedia.org/wiki/Xz",
    "xxxxx"
)
readUrl <- function(url) {
    out <- tryCatch(
        {
            # Just to highlight: if you want to use more than one 
            # R expression in the "try" part then you'll have to 
            # use curly brackets.
            # 'tryCatch()' will return the last evaluated expression 
            # in case the "try" part was completed successfully

            message("This is the 'try' part")

            readLines(con=url, warn=FALSE) 
            # The return value of `readLines()` is the actual value 
            # that will be returned in case there is no condition 
            # (e.g. warning or error). 
            # You don't need to state the return value via `return()` as code 
            # in the "try" part is not wrapped inside a function (unlike that
            # for the condition handlers for warnings and error below)
        },
        error=function(cond) {
            message(paste("URL does not seem to exist:", url))
            message("Here's the original error message:")
            message(cond)
            # Choose a return value in case of error
            return(NA)
        },
        warning=function(cond) {
            message(paste("URL caused a warning:", url))
            message("Here's the original warning message:")
            message(cond)
            # Choose a return value in case of warning
            return(NULL)
        },
        finally={
        # NOTE:
        # Here goes everything that should be executed at the end,
        # regardless of success or error.
        # If you want more than one expression to be executed, then you 
        # need to wrap them in curly brackets ({...}); otherwise you could
        # just have written 'finally=<expression>' 
            message(paste("Processed URL:", url))
            message("Some other message at the end")
        }
    )    
    return(out)
}

Applying the code

> y <- lapply(urls, readUrl)
Processed URL: http://stat.ethz.ch/R-manual/R-devel/library/base/html/connections.html
Some other message at the end
Processed URL: http://en.wikipedia.org/wiki/Xz
Some other message at the end
URL does not seem to exist: xxxxx
Here's the original error message:
cannot open the connection
Processed URL: xxxxx
Some other message at the end
Warning message:
In file(con, "r") : cannot open file 'xxxxx': No such file or directory

Investigating the output

> head(y[[1]])
[1] "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"      
[2] "<html><head><title>R: Functions to Manipulate Connections</title>"      
[3] "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">"
[4] "<link rel=\"stylesheet\" type=\"text/css\" href=\"R.css\">"             
[5] "</head><body>"                                                          
[6] ""    

> length(y)
[1] 3

> y[[3]]
[1] NA

Additional remarks

tryCatch

tryCatch returns the value associated to executing expr unless there's an error or a warning. In this case, specific return values (see return(NA) above) can be specified by supplying a respective handler function (see arguments error and warning in ?tryCatch). These can be functions that already exist, but you can also define them within tryCatch() (as I did above).

The implications of choosing specific return values of the handler functions

As we've specified that NA should be returned in case of error, the third element in y is NA. If we'd have chosen NULL to be the return value, the length of y would just have been 2 instead of 3 as lapply() will simply "ignore" return values that are NULL. Also note that if you don't specify an explicit return value via return(), the handler functions will return NULL (i.e. in case of an error or a warning condition).

"Undesired" warning message

As warn=FALSE doesn't seem to have any effect, an alternative way to suppress the warning (which in this case isn't really of interest) is to use

suppressWarnings(readLines(con=url))

instead of

readLines(con=url, warn=FALSE)

Multiple expressions

Note that you can also place multiple expressions in the "actual expressions part" (argument expr of tryCatch()) if you wrap them in curly brackets (just like I illustrated in the finally part).

Using Python 3 in virtualenv

I had the same ERROR message. tbrisker's solution did not work in my case. Instead this solved the issue:

$ python3 -m venv .env

ALTER TABLE ADD COLUMN IF NOT EXISTS in SQLite

If you are doing this in a DB upgrade statement, perhaps the simplest way is to just catch the exception thrown if you are attempting to add a field that may already exist.

try {
   db.execSQL("ALTER TABLE " + TABLE_NAME + " ADD COLUMN foo TEXT default null");
} catch (SQLiteException ex) {
   Log.w(TAG, "Altering " + TABLE_NAME + ": " + ex.getMessage());
}

Efficient way to rotate a list in python

I don't know if this is 'efficient', but it also works:

x = [1,2,3,4]
x.insert(0,x.pop())

EDIT: Hello again, I just found a big problem with this solution! Consider the following code:

class MyClass():
    def __init__(self):
        self.classlist = []

    def shift_classlist(self): # right-shift-operation
        self.classlist.insert(0, self.classlist.pop())

if __name__ == '__main__':
    otherlist = [1,2,3]
    x = MyClass()

    # this is where kind of a magic link is created...
    x.classlist = otherlist

    for ii in xrange(2): # just to do it 2 times
        print '\n\n\nbefore shift:'
        print '     x.classlist =', x.classlist
        print '     otherlist =', otherlist
        x.shift_classlist() 
        print 'after shift:'
        print '     x.classlist =', x.classlist
        print '     otherlist =', otherlist, '<-- SHOULD NOT HAVE BIN CHANGED!'

The shift_classlist() method executes the same code as my x.insert(0,x.pop())-solution, otherlist is a list indipendent from the class. After passing the content of otherlist to the MyClass.classlist list, calling the shift_classlist() also changes the otherlist list:

CONSOLE OUTPUT:

before shift:
     x.classlist = [1, 2, 3]
     otherlist = [1, 2, 3]
after shift:
     x.classlist = [3, 1, 2]
     otherlist = [3, 1, 2] <-- SHOULD NOT HAVE BIN CHANGED!



before shift:
     x.classlist = [3, 1, 2]
     otherlist = [3, 1, 2]
after shift:
     x.classlist = [2, 3, 1]
     otherlist = [2, 3, 1] <-- SHOULD NOT HAVE BIN CHANGED!

I use Python 2.7. I don't know if thats a bug, but I think it's more likely that I missunderstood something here.

Does anyone of you know why this happens?

Git submodule head 'reference is not a tree' error

This answer is for users of SourceTree with limited terminal git experience.

Open the problematic submodule from within the Git project (super-project).

Fetch and ensure 'Fetch all tags' is checked.

Rebase pull your Git project.

This will solve the 'reference is not a tree' problem 9 out of ten times. That 1 time it won't, is a terminal fix as described by the top answer.

Java regular expression OR operator

You can just use the pipe on its own:

"string1|string2"

for example:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string1|string2", "blah"));

Output:

blah, blah, string3

The main reason to use parentheses is to limit the scope of the alternatives:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string(1|2)", "blah"));

has the same output. but if you just do this:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string1|2", "blah"));

you get:

blah, stringblah, string3

because you've said "string1" or "2".

If you don't want to capture that part of the expression use ?::

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string(?:1|2)", "blah"));

How do I compile the asm generated by GCC?

gcc can use an assembly file as input, and invoke the assembler as needed. There is a subtlety, though:

  • If the file name ends with ".s" (lowercase 's'), then gcc calls the assembler.
  • If the file name ends with ".S" (uppercase 'S'), then gcc applies the C preprocessor on the source file (i.e. it recognizes directives such as #if and replaces macros), and then calls the assembler on the result.

So, on a general basis, you want to do things like this:

gcc -S file.c -o file.s
gcc -c file.s

iOS9 Untrusted Enterprise Developer with no option to trust

On iOS 9.2 Profiles renamed to Device Management.
Now navigation looks like that:
Settings -> General -> Device Management -> Tap on necessary profile in list -> Trust.

How to escape JSON string?

In .Net Core 3+ and .Net 5+:

string escapedJsonString = JsonEncodedText.Encode(jsonString);

How to check if a Docker image with a specific tag exist locally?

You can use like the following:

[ ! -z $(docker images -q someimage:sometag) ] || echo "does not exist"

Or:

[ -z $(docker images -q someimage:sometag) ] || echo "already exists"

jQuery.ajax returns 400 Bad Request

I think you just need to add 2 more options (contentType and dataType):

$('#my_get_related_keywords').click(function() {

    $.ajax({
            type: "POST",
            url: "HERE PUT THE PATH OF YOUR SERVICE OR PAGE",
            data: '{"HERE YOU CAN PUT DATA TO PASS AT THE SERVICE"}',
            contentType: "application/json; charset=utf-8", // this
            dataType: "json", // and this
            success: function (msg) {
               //do something
            },
            error: function (errormessage) {
                //do something else
            }
        });
}

Powershell v3 Invoke-WebRequest HTTPS error

Did you try using System.Net.WebClient?

$url = 'https://IPADDRESS/resource'
$wc = New-Object System.Net.WebClient
$wc.Credentials = New-Object System.Net.NetworkCredential("username","password")
$wc.DownloadString($url)

How to update values in a specific row in a Python Pandas DataFrame?

If you have one large dataframe and only a few update values I would use apply like this:

import pandas as pd

df = pd.DataFrame({'filename' :  ['test0.dat', 'test2.dat'], 
                                  'm': [12, 13], 'n' : [None, None]})

data = {'filename' :  'test2.dat', 'n':16}

def update_vals(row, data=data):
    if row.filename == data['filename']:
        row.n = data['n']
    return row

df.apply(update_vals, axis=1)

How many bits is a "word"?

This is from the book Hackers: Heroes of the Computer Revolution by Steven Levy.

.. the memory had been reduced to 4096 "words" of eighteen bits each. (A "bit" is a binary digit, either a 1 or 0. A series of binary numbers is called a "word").

As the other answers suggest, a "word" does not seem to have a fixed length.

SQL-Server: The backup set holds a backup of a database other than the existing

USE [master];
GO

CREATE DATABASE db;
GO

CREATE DATABASE db2;
GO

BACKUP DATABASE db TO DISK = 'c:\temp\db.bak' WITH INIT, COMPRESSION;
GO

RESTORE DATABASE db2
  FROM DISK = 'c:\temp\db.bak'
  WITH REPLACE,
  MOVE 'db' TO 'c:\temp\db2.mdf',
  MOVE 'db_log' TO 'c:\temp\db2.ldf';

bootstrap 4 file input doesn't show the file name

Johann-S solution works great. (And it looks like he created the awesome plugin)

The Bootstrap 4.3 documentation example page uses this plugin to modify the filename: https://github.com/Johann-S/bs-custom-file-input

Use the Bootstrap custom file input classes. Add the plugin to your project, and add this code in your script file on the page.

$(document).ready(function () {
  bsCustomFileInput.init()
})

Getting input values from text box

Javascript document.getElementById("<%=contrilid.ClientID%>").value; or using jquery

$("#<%= txt_iplength.ClientID %>").val();

Unable to launch the IIS Express Web server, Failed to register URL, Access is denied

This is for Visual Studio 2019, After trying a lot of suggestions that failed to work (including changing the port number etc) I solved my problem by deleting a file that was generated on my project's root folder called "debug". As soon as this file was deleted everything started working.

How to convert date to timestamp?

function getTimeStamp() {
       var now = new Date();
       return ((now.getMonth() + 1) + '/' + (now.getDate()) + '/' + now.getFullYear() + " " + now.getHours() + ':'
                     + ((now.getMinutes() < 10) ? ("0" + now.getMinutes()) : (now.getMinutes())) + ':' + ((now.getSeconds() < 10) ? ("0" + now
                     .getSeconds()) : (now.getSeconds())));
}

When to use setAttribute vs .attribute= in JavaScript?

methods for setting attributes(for example class) on an element: 1. el.className = string 2. el.setAttribute('class',string) 3. el.attributes.setNamedItem(object) 4. el.setAttributeNode(node)

I have made a simple benchmark test (here)

and it seems that setAttributeNode is about 3 times faster then using setAttribute.

so if performance is an issue - use "setAttributeNode"

How to use sed to extract substring

Explaining how you can use cut:

cat yourxmlfile | cut -d'"' -f2

It will 'cut' all the lines in the file based on " delimiter, and will take the 2nd field , which is what you wanted.

Map over object preserving keys

A mix fix for the underscore map bug :P

_.mixin({ 
    mapobj : function( obj, iteratee, context ) {
        if (obj == null) return [];
        iteratee = _.iteratee(iteratee, context);
        var keys = obj.length !== +obj.length && _.keys(obj),
            length = (keys || obj).length,
            results = {},
            currentKey;
        for (var index = 0; index < length; index++) {
          currentKey = keys ? keys[index] : index;
          results[currentKey] = iteratee(obj[currentKey], currentKey, obj);
        }
        if ( _.isObject( obj ) ) {
            return _.object( results ) ;
        } 
        return results;
    }
}); 

A simple workaround that keeps the right key and return as object It is still used the same way as i guest you could used this function to override the bugy _.map function

or simply as me used it as a mixin

_.mapobj ( options , function( val, key, list ) 

How to generate and manually insert a uniqueidentifier in sql server?

Kindly check Column ApplicationId datatype in Table aspnet_Users , ApplicationId column datatype should be uniqueidentifier .

*Your parameter order is passed wrongly , Parameter @id should be passed as first argument, but in your script it is placed in second argument..*

So error is raised..

Please refere sample script:

DECLARE @id uniqueidentifier
SET @id = NEWID()
Create Table #temp1(AppId uniqueidentifier)

insert into #temp1 values(@id)

Select * from #temp1

Drop Table #temp1

How can I calculate the difference between two dates?

If you want all the units, not just the biggest one, use one of these 2 methods (based on @Ankish's answer):

Example output: 28 D | 23 H | 59 M | 59 S

+ (NSString *) remaningTime:(NSDate *)startDate endDate:(NSDate *)endDate
{
    NSCalendarUnit units = NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
    NSDateComponents *components = [[NSCalendar currentCalendar] components:units fromDate: startDate toDate: endDate options: 0];
    return [NSString stringWithFormat:@"%ti D | %ti H | %ti M | %ti S", [components day], [components hour], [components minute], [components second]];
}

+ (NSString *) timeFromNowUntil:(NSDate *)endDate
{
    return [self remaningTime:[NSDate date] endDate:endDate];
}

Rollback to an old Git commit in a public repo

git read-tree -um @ $commit_to_revert_to

will do it. It's "git checkout" but without updating HEAD.

You can achieve the same effect with

git checkout $commit_to_revert_to
git reset --soft @{1}

if you prefer stringing convenience commands together.

These leave you with your worktree and index in the desired state, you can just git commit to finish.

REST vs JSON-RPC?

First, HTTP-REST is a "representational state transfer" architecture. This implies a lot of interesting things:

  • Your API will be stateless and therefore much easier to design (it's really easy to forget a transition in a complex automaton), and to integrate with independent software parts.
  • You will be lead to design read methods as safe ones, which will be easy to cache, and to integrate.
  • You will be lead to design write methods as idempotent ones, which will deal much better with timeouts.

Second, HTTP-REST is fully compliant with HTTP (see "safe" and "idempotent" in the previous part), therefore you will be able to reuse HTTP libraries (existing for every existing language) and HTTP reverse proxies, which will give you the ability to implement advanced features (cache, authentication, compression, redirection, rewriting, logging, etc.) with zero line of code.

Last but not least, using HTTP as an RPC protocol is a huge error according to the designer of HTTP 1.1 (and inventor of REST): http://www.ics.uci.edu/~fielding/pubs/dissertation/evaluation.htm#sec_6_5_2

Programmatically set TextBlock Foreground Color

Foreground needs a Brush, so you can use

textBlock.Foreground = Brushes.Navy;

If you want to use the color from RGB or ARGB then

textBlock.Foreground = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Color.FromArgb(100, 255, 125, 35)); 

or

textBlock.Foreground = new System.Windows.Media.SolidColorBrush(Colors.Navy); 

To get the Color from Hex

textBlock.Foreground = new System.Windows.Media.SolidColorBrush((Color)ColorConverter.ConvertFromString("#FFDFD991")); 

"Comparison method violates its general contract!"

Java does not check consistency in a strict sense, only notifies you if it runs into serious trouble. Also it does not give you much information from the error.

I was puzzled with what's happening in my sorter and made a strict consistencyChecker, maybe this will help you:

/**
 * @param dailyReports
 * @param comparator
 */
public static <T> void checkConsitency(final List<T> dailyReports, final Comparator<T> comparator) {
  final Map<T, List<T>> objectMapSmallerOnes = new HashMap<T, List<T>>();

  iterateDistinctPairs(dailyReports.iterator(), new IPairIteratorCallback<T>() {
    /**
     * @param o1
     * @param o2
     */
    @Override
    public void pair(T o1, T o2) {
      final int diff = comparator.compare(o1, o2);
      if (diff < Compare.EQUAL) {
        checkConsistency(objectMapSmallerOnes, o1, o2);
        getListSafely(objectMapSmallerOnes, o2).add(o1);
      } else if (Compare.EQUAL < diff) {
        checkConsistency(objectMapSmallerOnes, o2, o1);
        getListSafely(objectMapSmallerOnes, o1).add(o2);
      } else {
        throw new IllegalStateException("Equals not expected?");
      }
    }
  });
}

/**
 * @param objectMapSmallerOnes
 * @param o1
 * @param o2
 */
static <T> void checkConsistency(final Map<T, List<T>> objectMapSmallerOnes, T o1, T o2) {
  final List<T> smallerThan = objectMapSmallerOnes.get(o1);

  if (smallerThan != null) {
    for (final T o : smallerThan) {
      if (o == o2) {
        throw new IllegalStateException(o2 + "  cannot be smaller than " + o1 + " if it's supposed to be vice versa.");
      }
      checkConsistency(objectMapSmallerOnes, o, o2);
    }
  }
}

/**
 * @param keyMapValues 
 * @param key 
 * @param <Key> 
 * @param <Value> 
 * @return List<Value>
 */ 
public static <Key, Value> List<Value> getListSafely(Map<Key, List<Value>> keyMapValues, Key key) {
  List<Value> values = keyMapValues.get(key);

  if (values == null) {
    keyMapValues.put(key, values = new LinkedList<Value>());
  }

  return values;
}

/**
 * @author Oku
 *
 * @param <T>
 */
public interface IPairIteratorCallback<T> {
  /**
   * @param o1
   * @param o2
   */
  void pair(T o1, T o2);
}

/**
 * 
 * Iterates through each distinct unordered pair formed by the elements of a given iterator
 *
 * @param it
 * @param callback
 */
public static <T> void iterateDistinctPairs(final Iterator<T> it, IPairIteratorCallback<T> callback) {
  List<T> list = Convert.toMinimumArrayList(new Iterable<T>() {

    @Override
    public Iterator<T> iterator() {
      return it;
    }

  });

  for (int outerIndex = 0; outerIndex < list.size() - 1; outerIndex++) {
    for (int innerIndex = outerIndex + 1; innerIndex < list.size(); innerIndex++) {
      callback.pair(list.get(outerIndex), list.get(innerIndex));
    }
  }
}

Convert seconds to HH-MM-SS with JavaScript?

For the special case of HH:MM:SS.MS (eq: "00:04:33.637") as used by FFMPEG to specify milliseconds.

[-][HH:]MM:SS[.m...]

HH expresses the number of hours, MM the number of minutes for a maximum of 2 digits, and SS the number of seconds for a maximum of 2 digits. The m at the end expresses decimal value for SS.

_x000D_
_x000D_
/* HH:MM:SS.MS to (FLOAT)seconds ---------------*/
function timerToSec(timer){
   let vtimer = timer.split(":")
   let vhours = +vtimer[0]
   let vminutes = +vtimer[1]
   let vseconds = parseFloat(vtimer[2])
   return vhours * 3600 + vminutes * 60 + vseconds
}

/* Seconds to (STRING)HH:MM:SS.MS --------------*/
function secToTimer(sec){
  let o = new Date(0)
  let p =  new Date(sec*1000)  
  return new Date(p.getTime()-o.getTime())
    .toISOString()
    .split("T")[1]
    .split("Z")[0]
}

/* Example: 7hours, 4 minutes, 33 seconds and 637 milliseconds */
const t = "07:04:33.637"
console.log(
  t + " => " +
  timerToSec(t) +
  "s"
)

/* Test: 25473 seconds and 637 milliseconds */
const s = 25473.637 // "25473.637"
console.log(
  s + "s => " + 
  secToTimer(s)
)
_x000D_
_x000D_
_x000D_

Example usage, a milliseconds transport timer:

_x000D_
_x000D_
/* Seconds to (STRING)HH:MM:SS.MS --------------*/
function secToTimer(sec){
  let o = new Date(0)
  let p =  new Date(sec*1000)  
  return new Date(p.getTime()-o.getTime())
    .toISOString()
    .split("T")[1]
    .split("Z")[0]
}

let job, origin = new Date().getTime()
const timer = () => {
  job = requestAnimationFrame(timer)
  OUT.textContent = secToTimer((new Date().getTime() - origin) / 1000)
}

requestAnimationFrame(timer)
_x000D_
span {font-size:4rem}
_x000D_
<span id="OUT"></span>
<br>
<button onclick="origin = new Date().getTime()">RESET</button>
<button onclick="requestAnimationFrame(timer)">RESTART</button>
<button onclick="cancelAnimationFrame(job)">STOP</button>
_x000D_
_x000D_
_x000D_

Example usage, binded to a media element

_x000D_
_x000D_
/* Seconds to (STRING)HH:MM:SS.MS --------------*/
function secToTimer(sec){
  let o = new Date(0)
  let p =  new Date(sec*1000)  
  return new Date(p.getTime()-o.getTime())
    .toISOString()
    .split("T")[1]
    .split("Z")[0]
}

VIDEO.addEventListener("timeupdate", function(e){
  OUT.textContent = secToTimer(e.target.currentTime)
}, false)
_x000D_
span {font-size:4rem}
_x000D_
<span id="OUT"></span><br>
<video id="VIDEO" width="400" controls autoplay>
  <source src="https://www.w3schools.com/html/mov_bbb.mp4" type="video/mp4">
</video>
_x000D_
_x000D_
_x000D_


Outside the question, those functions written in php:

<?php 
/* HH:MM:SS to (FLOAT)seconds ------------------*/
function timerToSec($timer){
  $vtimer = explode(":",$timer);
  $vhours = (int)$vtimer[0];
  $vminutes = (int)$vtimer[1];
  $vseconds = (float)$vtimer[2];
  return $vhours * 3600 + $vminutes * 60 + $vseconds;
}
/* Seconds to (STRING)HH:MM:SS -----------------*/
function secToTimer($sec){
  return explode(" ", date("H:i:s", $sec))[0];  
}

Opening XML page shows "This XML file does not appear to have any style information associated with it."

This XML file does not appear to have any style information associated with it. The document tree is shown below.

You will get this error in the client side when the client (the webbrowser) for some reason interprets the HTTP response content as text/xml instead of text/html and the parsed XML tree doesn't have any XML-stylesheet. In other words, the webbrowser incorrectly parsed the retrieved HTTP response content as XML instead of as HTML due to the wrong or missing HTTP response content type.

In case of JSF/Facelets files which have the default extension of .xhtml, that can in turn happen if the HTTP request hasn't invoked the FacesServlet and thus it wasn't able to parse the Facelets file and generate the desired HTML output based on the XHTML source code. Firefox is then merely guessing the HTTP response content type based on the .xhtml file extension which is in your Firefox configuration apparently by default interpreted as text/xml.

You need to make sure that the HTTP request URL, as you see in browser's address bar, matches the <url-pattern> of the FacesServlet as registered in webapp's web.xml, so that it will be invoked and be able to generate the desired HTML output based on the XHTML source code. If it's for example *.jsf, then you need to open the page by /some.jsf instead of /some.xhtml. Alternatively, you can also just change the <url-pattern> to *.xhtml. This way you never need to fiddle with virtual URLs.

See also:


Note thus that you don't actually need a XML stylesheet. This all was just misinterpretation by the webbrowser while trying to do its best to make something presentable out of the retrieved HTTP response content. It should actually have retrieved the properly generated HTML output, Firefox surely knows precisely how to deal with HTML content.

Accessing items in an collections.OrderedDict by index

This community wiki attempts to collect existing answers.

Python 2.7

In python 2, the keys(), values(), and items() functions of OrderedDict return lists. Using values as an example, the simplest way is

d.values()[0]  # "python"
d.values()[1]  # "spam"

For large collections where you only care about a single index, you can avoid creating the full list using the generator versions, iterkeys, itervalues and iteritems:

import itertools
next(itertools.islice(d.itervalues(), 0, 1))  # "python"
next(itertools.islice(d.itervalues(), 1, 2))  # "spam"

The indexed.py package provides IndexedOrderedDict, which is designed for this use case and will be the fastest option.

from indexed import IndexedOrderedDict
d = IndexedOrderedDict({'foo':'python','bar':'spam'})
d.values()[0]  # "python"
d.values()[1]  # "spam"

Using itervalues can be considerably faster for large dictionaries with random access:

$ python2 -m timeit -s 'from collections import OrderedDict; from random import randint; size = 1000;   d = OrderedDict({i:i for i in range(size)})'  'i = randint(0, size-1); d.values()[i:i+1]'
1000 loops, best of 3: 259 usec per loop
$ python2 -m timeit -s 'from collections import OrderedDict; from random import randint; size = 10000;  d = OrderedDict({i:i for i in range(size)})' 'i = randint(0, size-1); d.values()[i:i+1]'
100 loops, best of 3: 2.3 msec per loop
$ python2 -m timeit -s 'from collections import OrderedDict; from random import randint; size = 100000; d = OrderedDict({i:i for i in range(size)})' 'i = randint(0, size-1); d.values()[i:i+1]'
10 loops, best of 3: 24.5 msec per loop

$ python2 -m timeit -s 'from collections import OrderedDict; from random import randint; size = 1000;   d = OrderedDict({i:i for i in range(size)})' 'i = randint(0, size-1); next(itertools.islice(d.itervalues(), i, i+1))'
10000 loops, best of 3: 118 usec per loop
$ python2 -m timeit -s 'from collections import OrderedDict; from random import randint; size = 10000;  d = OrderedDict({i:i for i in range(size)})' 'i = randint(0, size-1); next(itertools.islice(d.itervalues(), i, i+1))'
1000 loops, best of 3: 1.26 msec per loop
$ python2 -m timeit -s 'from collections import OrderedDict; from random import randint; size = 100000; d = OrderedDict({i:i for i in range(size)})' 'i = randint(0, size-1); next(itertools.islice(d.itervalues(), i, i+1))'
100 loops, best of 3: 10.9 msec per loop

$ python2 -m timeit -s 'from indexed import IndexedOrderedDict; from random import randint; size = 1000;   d = IndexedOrderedDict({i:i for i in range(size)})' 'i = randint(0, size-1); d.values()[i]'
100000 loops, best of 3: 2.19 usec per loop
$ python2 -m timeit -s 'from indexed import IndexedOrderedDict; from random import randint; size = 10000;  d = IndexedOrderedDict({i:i for i in range(size)})' 'i = randint(0, size-1); d.values()[i]'
100000 loops, best of 3: 2.24 usec per loop
$ python2 -m timeit -s 'from indexed import IndexedOrderedDict; from random import randint; size = 100000; d = IndexedOrderedDict({i:i for i in range(size)})' 'i = randint(0, size-1); d.values()[i]'
100000 loops, best of 3: 2.61 usec per loop

+--------+-----------+----------------+---------+
|  size  | list (ms) | generator (ms) | indexed |
+--------+-----------+----------------+---------+
|   1000 | .259      | .118           | .00219  |
|  10000 | 2.3       | 1.26           | .00224  |
| 100000 | 24.5      | 10.9           | .00261  |
+--------+-----------+----------------+---------+

Python 3.6

Python 3 has the same two basic options (list vs generator), but the dict methods return generators by default.

List method:

list(d.values())[0]  # "python"
list(d.values())[1]  # "spam"

Generator method:

import itertools
next(itertools.islice(d.values(), 0, 1))  # "python"
next(itertools.islice(d.values(), 1, 2))  # "spam"

Python 3 dictionaries are an order of magnitude faster than python 2 and have similar speedups for using generators.

+--------+-----------+----------------+---------+
|  size  | list (ms) | generator (ms) | indexed |
+--------+-----------+----------------+---------+
|   1000 | .0316     | .0165          | .00262  |
|  10000 | .288      | .166           | .00294  |
| 100000 | 3.53      | 1.48           | .00332  |
+--------+-----------+----------------+---------+

How do you clear Apache Maven's cache?

Use mvn dependency:purge-local-repository -DactTransitively=false -Dskip=true if you have maven plugins as one of the modules. Otherwise Maven will try to recompile them, thus downloading the dependencies again.

Use formula in custom calculated field in Pivot Table

I'll post this comment as answer, as I'm confident enough that what I asked is not possible.

I) Couple of similar questions trying to do the same, without success:

II) This article: Excel Pivot Table Calculated Field for example lists many restrictions of Calculated Field:

  • For calculated fields, the individual amounts in the other fields are summed, and then the calculation is performed on the total amount.
  • Calculated field formulas cannot refer to the pivot table totals or subtotals
  • Calculated field formulas cannot refer to worksheet cells by address or by name.
  • Sum is the only function available for a calculated field.
  • Calculated fields are not available in an OLAP-based pivot table.

III) There is tiny limited possibility to use AVERAGE() and similar function for a range of cells, but that applies only if Pivot table doesn't have grouped cells, which allows listing the cells as items in new group (right to "Fileds" listbox in above screenshot) and then user can calculate AVERAGE(), referencing explicitly every item (cell), from Items listbox, as argument. Maybe it's better explained here: Calculate values in a PivotTable report
For my Pivot table it wasn't applicable because my range wasn't small enough, this option to be sane choice.

Error creating bean with name

It looks like your Spring component scan Base is missing UserServiceImpl

<context:component-scan base-package="org.assessme.com.controller." />

How to format column to number format in Excel sheet?

This will format column A as text, B as General, C as a number.

Sub formatColumns()
 Columns(1).NumberFormat = "@"
 Columns(2).NumberFormat = "General"
 Columns(3).NumberFormat = "0"
End Sub

How to write a cursor inside a stored procedure in SQL Server 2008

Try the following snippet. You can call the the below stored procedure from your application, so that NoOfUses in the coupon table will be updated.

CREATE PROCEDURE [dbo].[sp_UpdateCouponCount]
AS

Declare     @couponCount int,
            @CouponName nvarchar(50),
            @couponIdFromQuery int


Declare curP cursor For

  select COUNT(*) as totalcount , Name as name,couponuse.couponid  as couponid from Coupon as coupon 
  join CouponUse as couponuse on coupon.id = couponuse.couponid
  where couponuse.id=@cuponId
  group by couponuse.couponid , coupon.Name

OPEN curP 
Fetch Next From curP Into @couponCount, @CouponName,@couponIdFromQuery

While @@Fetch_Status = 0 Begin

    print @couponCount
    print @CouponName

    update Coupon SET NoofUses=@couponCount
    where couponuse.id=@couponIdFromQuery


Fetch Next From curP Into @couponCount, @CouponName,@couponIdFromQuery

End -- End of Fetch

Close curP
Deallocate curP

Hope this helps!

Test if a string contains a word in PHP?

Use strpos. If the string is not found it returns false, otherwise something that is not false. Be sure to use a type-safe comparison (===) as 0 may be returned and it is a falsy value:

if (strpos($string, $substring) === false) {
    // substring is not found in string
}

if (strpos($string, $substring2) !== false) {
    // substring2 is found in string
}

How do I escape double and single quotes in sed?

My problem was that I needed to have the "" outside the expression since I have a dynamic variable inside the sed expression itself. So than the actual solution is that one from lenn jackman that you replace the " inside the sed regex with [\"].

So my complete bash is:

RELEASE_VERSION="0.6.6"

sed -i -e "s#value=[\"]trunk[\"]#value=\"tags/$RELEASE_VERSION\"#g" myfile.xml

Here is:

# is the sed separator

[\"] = " in regex

value = \"tags/$RELEASE_VERSION\" = my replacement string, important it has just the \" for the quotes

How SID is different from Service name in Oracle tnsnames.ora

what is a SID and Service name

please look into oracle's documentation at https://docs.oracle.com/cd/B19306_01/network.102/b14212/concepts.htm

In case if the above link is not accessable in future, At the time time of writing this answer, the above link will direct you to, "Database Service and Database Instance Identification" topic in Connectivity Concepts chapter of "Database Net Services Administrator's Guide". This guide is published by oracle as part of "Oracle Database Online Documentation, 10g Release 2 (10.2)"

When I have to use one or another? Why do I need two of them?

Consider below mapping in a RAC Environment,

SID      SERVICE_NAME
bob1    bob
bob2    bob
bob3    bob
bob4    bob

if load balancing is configured, the listener will 'balance' the workload across all four SIDs. Even if load balancing is configured, you can connect to bob1 all the time if you want to by using the SID instead of SERVICE_NAME.

Please refer, https://community.oracle.com/thread/4049517

MySQL query finding values in a comma separated string

If the set of colors is more or less fixed, the most efficient and also most readable way would be to use string constants in your app and then use MySQL's SET type with FIND_IN_SET('red',colors) in your queries. When using the SET type with FIND_IN_SET, MySQL uses one integer to store all values and uses binary "and" operation to check for presence of values which is way more efficient than scanning a comma-separated string.

In SET('red','blue','green'), 'red' would be stored internally as 1, 'blue' would be stored internally as 2 and 'green' would be stored internally as 4. The value 'red,blue' would be stored as 3 (1|2) and 'red,green' as 5 (1|4).

Convert DOS line endings to Linux line endings in Vim

I knew I'd seen this somewhere. Here is the FreeBSD login tip:

Do you need to remove all those ^M characters from a DOS file? Try

tr -d \\r < dosfile > newfile
    -- Originally by Dru <[email protected]>

Where does VBA Debug.Print log to?

Debug.Print outputs to the "Immediate" window.

Debug.Print outputs to the Immediate window

Also, you can simply type ? and then a statement directly into the immediate window (and then press Enter) and have the output appear right below, like this:

simply type ? and then a statement directly into the immediate window

This can be very handy to quickly output the property of an object...

? myWidget.name

...to set the property of an object...

myWidget.name = "thingy"

...or to even execute a function or line of code, while in debugging mode:

Sheet1.MyFunction()

git push to specific branch

The answers in question you linked-to are all about configuring git so that you can enter very short git push commands and have them do whatever you want. Which is great, if you know what you want and how to spell that in Git-Ese, but you're new to git! :-)

In your case, Petr Mensik's answer is the (well, "a") right one. Here's why:

The command git push remote roots around in your .git/config file to find the named "remote" (e.g., origin). The config file lists:

  • where (URL-wise) that remote "lives" (e.g., ssh://hostname/path)
  • where pushes go, if different
  • what gets pushed, if you didn't say what branch(es) to push
  • what gets fetched when you run git fetch remote

When you first cloned the repo—whenever that was—git set up default values for some of these. The URL is whatever you cloned from and the rest, if set or unset, are all "reasonable" defaults ... or, hmm, are they?

The issue with these is that people have changed their minds, over time, as to what is "reasonable". So now (depending on your version of git and whether you've configured things in detail), git may print a lot of warnings about defaults changing in the future. Adding the name of the "branch to push"—amd_qlp_tester—(1) shuts it up, and (2) pushes just that one branch.

If you want to push more conveniently, you could do that with:

git push origin

or even:

git push

but whether that does what you want, depends on whether you agree with "early git authors" that the original defaults are reasonable, or "later git authors" that the original defaults aren't reasonable. So, when you want to do all the configuration stuff (eventually), see the question (and answers) you linked-to.

As for the name origin/amd_qlp_tester in the first place: that's actually a local entity (a name kept inside your repo), even though it's called a "remote branch". It's git's best guess at "where amd_qlp_tester is over there". Git updates it when it can.

Apache is not running from XAMPP Control Panel ( Error: Apache shutdown unexpectedly. This may be due to a blocked port)

If you are installed Skype, Please check this option.

enter image description here

Another case is Windows 10

Check this:

  1. Go to Start, type in services.msc
  2. Scroll down in the Services window to find the World Wide Web Publishing Service.
  3. Right-click on it, and select Stop or Disable it if you just want to use XAMPP only.

enter image description here

Extension exists but uuid_generate_v4 fails

If you've changed the search_path, specify the public schema in the function call:

public.uuid_generate_v4()

Composer killed while updating

Solved on Laravel/Homestead (Vagrant Windows)

  1. Edit Homestead.yaml and increase memory from 2048 to 4096

  2. vagrant up

  3. vagrant ssh

  4. Install Symfony with this line on the folder you choose (must be without files)

    COMPOSER_MEMORY_LIMIT=-1 composer create-project symfony/website-skeleton . -s dev
    

What does the question mark and the colon (?: ternary operator) mean in objective-c?

Fun fact, in objective-c if you want to check null / nil For example:

-(NSString*) getSomeStringSafeCheck
{
    NSString *string = [self getSomeString];
    if(string != nil){
        return String;
    }
    return @"";
}

The quick way to do it is:

-(NSString*) getSomeStringSafeCheck
{
    return [self getSomeString] != nil ? [self getSomeString] : @"";
}

Then you can update it to a simplest way:

-(NSString*) getSomeStringSafeCheck
{
    return [self getSomeString]?: @"";
}

Because in Objective-C:

  1. if an object is nil, it will return false as boolean;
  2. Ternary Operator's second parameter can be empty, as it will return the result on the left of '?'

So let say you write:

[self getSomeString] != nil?: @"";

the second parameter is returning a boolean value, thus a exception is thrown.

100% Min Height CSS layout

First you should create a div with id='footer' after your content div and then simply do this.

Your HTML should look like this:

<html>
    <body>
        <div id="content">
            ...
        </div>
        <div id="footer"></div>
    </body>
</html>

And the CSS:

?html, body {
    height: 100%;   
}
#content {
    height: 100%;
}
#footer {
    clear: both;        
}

How to change the default charset of a MySQL table?

If you want to change the table default character set and all character columns to a new character set, use a statement like this:

ALTER TABLE tbl_name CONVERT TO CHARACTER SET charset_name;

So query will be:

ALTER TABLE etape_prospection CONVERT TO CHARACTER SET utf8;

What are the best practices for using a GUID as a primary key, specifically regarding performance?

GUIDs may seem to be a natural choice for your primary key - and if you really must, you could probably argue to use it for the PRIMARY KEY of the table. What I'd strongly recommend not to do is use the GUID column as the clustering key, which SQL Server does by default, unless you specifically tell it not to.

You really need to keep two issues apart:

  1. the primary key is a logical construct - one of the candidate keys that uniquely and reliably identifies every row in your table. This can be anything, really - an INT, a GUID, a string - pick what makes most sense for your scenario.

  2. the clustering key (the column or columns that define the "clustered index" on the table) - this is a physical storage-related thing, and here, a small, stable, ever-increasing data type is your best pick - INT or BIGINT as your default option.

By default, the primary key on a SQL Server table is also used as the clustering key - but that doesn't need to be that way! I've personally seen massive performance gains when breaking up the previous GUID-based Primary / Clustered Key into two separate key - the primary (logical) key on the GUID, and the clustering (ordering) key on a separate INT IDENTITY(1,1) column.

As Kimberly Tripp - the Queen of Indexing - and others have stated a great many times - a GUID as the clustering key isn't optimal, since due to its randomness, it will lead to massive page and index fragmentation and to generally bad performance.

Yes, I know - there's newsequentialid() in SQL Server 2005 and up - but even that is not truly and fully sequential and thus also suffers from the same problems as the GUID - just a bit less prominently so.

Then there's another issue to consider: the clustering key on a table will be added to each and every entry on each and every non-clustered index on your table as well - thus you really want to make sure it's as small as possible. Typically, an INT with 2+ billion rows should be sufficient for the vast majority of tables - and compared to a GUID as the clustering key, you can save yourself hundreds of megabytes of storage on disk and in server memory.

Quick calculation - using INT vs. GUID as Primary and Clustering Key:

  • Base Table with 1'000'000 rows (3.8 MB vs. 15.26 MB)
  • 6 nonclustered indexes (22.89 MB vs. 91.55 MB)

TOTAL: 25 MB vs. 106 MB - and that's just on a single table!

Some more food for thought - excellent stuff by Kimberly Tripp - read it, read it again, digest it! It's the SQL Server indexing gospel, really.

PS: of course, if you're dealing with just a few hundred or a few thousand rows - most of these arguments won't really have much of an impact on you. However: if you get into the tens or hundreds of thousands of rows, or you start counting in millions - then those points become very crucial and very important to understand.

Update: if you want to have your PKGUID column as your primary key (but not your clustering key), and another column MYINT (INT IDENTITY) as your clustering key - use this:

CREATE TABLE dbo.MyTable
(PKGUID UNIQUEIDENTIFIER NOT NULL,
 MyINT INT IDENTITY(1,1) NOT NULL,
 .... add more columns as needed ...... )

ALTER TABLE dbo.MyTable
ADD CONSTRAINT PK_MyTable
PRIMARY KEY NONCLUSTERED (PKGUID)

CREATE UNIQUE CLUSTERED INDEX CIX_MyTable ON dbo.MyTable(MyINT)

Basically: you just have to explicitly tell the PRIMARY KEY constraint that it's NONCLUSTERED (otherwise it's created as your clustered index, by default) - and then you create a second index that's defined as CLUSTERED

This will work - and it's a valid option if you have an existing system that needs to be "re-engineered" for performance. For a new system, if you start from scratch, and you're not in a replication scenario, then I'd always pick ID INT IDENTITY(1,1) as my clustered primary key - much more efficient than anything else!

Running ASP.Net on a Linux based server

For ASP.NET on Linux, check out Mono.

That said, thousands of sites run on Windows Server without any issues. A poorly-configured server with any OS will be vulnerable; Linux won't save you from a poor admin.

So I guess my "best practice" for deplying an ASP.NET app would be to use Windows Server 2008 (likely Web edition). And hire a good administrator.

Java Keytool error after importing certificate , "keytool error: java.io.FileNotFoundException & Access Denied"

You can give yourself permissions to fix this problem.

Right click on cacerts > choose properties > select Securit tab > Allow all permissions to all the Group and user names.

This worked for me.

How to change Android usb connect mode to charge only?

In your phone go to Settings->Connect to PC.

There you will see the option Default Connection Type. Select it and set it to your preference.

Generate MD5 hash string with T-SQL

None of the other answers worked for me. Note that SQL Server will give different results if you pass in a hard-coded string versus feed it from a column in your result set. Below is the magic that worked for me to give a perfect match between SQL Server and MySql

select LOWER(CONVERT(VARCHAR(32), HashBytes('MD5', CONVERT(varchar, EmailAddress)), 2)) from ...

Find elements inside forms and iframe using Java and Selenium WebDriver

When using an iframe, you will first have to switch to the iframe, before selecting the elements of that iframe

You can do it using:

driver.switchTo().frame(driver.findElement(By.id("frameId")));
//do your stuff
driver.switchTo().defaultContent();

In case if your frameId is dynamic, and you only have one iframe, you can use something like:

driver.switchTo().frame(driver.findElement(By.tagName("iframe")));

grunt: command not found when running from terminal

For windows

npm install -g grunt-cli

npm install load-grunt-tasks

Then run

grunt

Django DateField default options

You could also use lambda. Useful if you're using django.utils.timezone.now

date = models.DateField(_("Date"), default=lambda: now().date())

MSBUILD : error MSB1008: Only one project can be specified

I was using single quotes around the password parameter when I got the error

/p:password='my secret' bad

and changed it to use double quotes to resolve the issue.

/p:password="my secret" good

Likely the same would apply to any parameter that needs quotes for values that contain a space.

Change Timezone in Lumen or Laravel 5

By default time zone of laravel project is **UTC*

  • you can find time zone setting in App.php of config folder

'timezone' => 'UTC',

now change according to your time zone for me it's Asia/Calcutta

so for me setting will be 'timezone' => 'Asia/Calcutta',

  • After changing your time zone setting run command php artisan config:cache

*for time zone list visit this url https://www.w3schools.com/php/php_ref_timezones.asp

Delegates in swift?

DELEGATES IN SWIFT 2

I am explaining with example of Delegate with two viewControllers.In this case, SecondVC Object is sending data back to first View Controller.

Class with Protocol Declaration

protocol  getDataDelegate  {
    func getDataFromAnotherVC(temp: String)
}


import UIKit
class SecondVC: UIViewController {

    var delegateCustom : getDataDelegate?
    override func viewDidLoad() {
        super.viewDidLoad()
     }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    @IBAction func backToMainVC(sender: AnyObject) {
      //calling method defined in first View Controller with Object  
      self.delegateCustom?.getDataFromAnotherVC(temp: "I am sending data from second controller to first view controller.Its my first delegate example. I am done with custom delegates.")
        self.navigationController?.popViewControllerAnimated(true)
    }
    
}

In First ViewController Protocol conforming is done here:

class ViewController: UIViewController, getDataDelegate

Protocol method definition in First View Controller(ViewController)

func getDataFromAnotherVC(temp : String)
{
  // dataString from SecondVC
   lblForData.text = dataString
}

During push the SecondVC from First View Controller (ViewController)

let objectPush = SecondVC()
objectPush.delegateCustom = self
self.navigationController.pushViewController(objectPush, animated: true)

TypeError: 'str' does not support the buffer interface

This problem commonly occurs when switching from py2 to py3. In py2 plaintext is both a string and a byte array type. In py3 plaintext is only a string, and the method outfile.write() actually takes a byte array when outfile is opened in binary mode, so an exception is raised. Change the input to plaintext.encode('utf-8') to fix the problem. Read on if this bothers you.

In py2, the declaration for file.write made it seem like you passed in a string: file.write(str). Actually you were passing in a byte array, you should have been reading the declaration like this: file.write(bytes). If you read it like this the problem is simple, file.write(bytes) needs a bytes type and in py3 to get bytes out of a str you convert it:

py3>> outfile.write(plaintext.encode('utf-8'))

Why did the py2 docs declare file.write took a string? Well in py2 the declaration distinction didn't matter because:

py2>> str==bytes         #str and bytes aliased a single hybrid class in py2
True

The str-bytes class of py2 has methods/constructors that make it behave like a string class in some ways and a byte array class in others. Convenient for file.write isn't it?:

py2>> plaintext='my string literal'
py2>> type(plaintext)
str                              #is it a string or is it a byte array? it's both!

py2>> outfile.write(plaintext)   #can use plaintext as a byte array

Why did py3 break this nice system? Well because in py2 basic string functions didn't work for the rest of the world. Measure the length of a word with a non-ASCII character?

py2>> len('¡no')        #length of string=3, length of UTF-8 byte array=4, since with variable len encoding the non-ASCII chars = 2-6 bytes
4                       #always gives bytes.len not str.len

All this time you thought you were asking for the len of a string in py2, you were getting the length of the byte array from the encoding. That ambiguity is the fundamental problem with double-duty classes. Which version of any method call do you implement?

The good news then is that py3 fixes this problem. It disentangles the str and bytes classes. The str class has string-like methods, the separate bytes class has byte array methods:

py3>> len('¡ok')       #string
3
py3>> len('¡ok'.encode('utf-8'))     #bytes
4

Hopefully knowing this helps de-mystify the issue, and makes the migration pain a little easier to bear.

How do I stop a program when an exception is raised in Python?

import sys

try:
  print("stuff")
except:
  sys.exit(1) # exiing with a non zero value is better for returning from an error

How to have the formatter wrap code with IntelliJ?

You can create a macro for Ctrl +Shift + S (for example) that do all this things:

Edit > Macros > Start Macro Recording (the recording will start). Click where you need.

For example:

Code > Reformat Code
Code > Auto-Indent Lines
Code > Optimize Imports
Code > Rearrange Code
File > Save All
... (all that you want)

Then, click on red button in bottom-right of the IDE to stop the Macro recording.

Set a macro name.

Go to File > Settings > Macros > YOUR MACRO NAME.

Right Click > Add Keyboard Shortcut, and type Ctrl + Shift + S.

How to resolve the error "Unable to access jarfile ApacheJMeter.jar errorlevel=1" while initiating Jmeter?

I faced with the same error, when i downloaded the Jmeter Source, and it got fixed once i downloaded Jmeter Binary. Please watch this video.

Show/hide div if checkbox selected

<input type="checkbox" name="check1" value="checkbox" onchange="showMe('div1')" /> checkbox

<div id="div1" style="display:none;">NOTICE</div>

  <script type="text/javascript">
<!--
   function showMe (box) {
    var chboxs = document.getElementById("div1").style.display;
    var vis = "none";
        if(chboxs=="none"){
         vis = "block"; }
        if(chboxs=="block"){
         vis = "none"; }
    document.getElementById(box).style.display = vis;
}
  //-->
</script>

int to string in MySQL

Try it using CONCAT

CONCAT('site.com/path/','%', CAST(t1.id AS CHAR(25)), '%','/more')

Is there a link to the "latest" jQuery library on Google APIs?

Up until jQuery 1.11.1, you could use the following URLs to get the latest version of jQuery:

For example:

<script src="https://code.jquery.com/jquery-latest.min.js"></script>

However, since jQuery 1.11.1, both jQuery and Google stopped updating these URL's; they will forever be fixed at 1.11.1. There is no supported alternative URL to use. For an explanation of why this is the case, see this blog post; Don't use jquery-latest.js.

Both hosts support https as well as http, so change the protocol as you see fit (or use a protocol relative URI)

See also: https://developers.google.com/speed/libraries/devguide

Visual Studio C# IntelliSense not automatically displaying

Deleting the .vs folder in the solution solved my issue. You have to exit from Visual Studio and then delete the .vs folder and start Visual Studio again.

How do I fix 'ImportError: cannot import name IncompleteRead'?

On Ubuntu 14.04 I resolved this by using the pip installation bootstrap script, as described in the documentation

wget https://bootstrap.pypa.io/get-pip.py
sudo python get-pip.py

That's an OK solution for a development environment.

How do I reset a sequence in Oracle?

alter sequence serial restart start with 1;

This feature was officially added in 18c but is unofficially available since 12.1.

It is arguably safe to use this undocumented feature in 12.1. Even though the syntax is not included in the official documentation, it is generated by the Oracle package DBMS_METADATA_DIFF. I've used it several times on production systems. However, I created an Oracle Service request and they verified that it's not a documentation bug, the feature is truly unsupported.

In 18c, the feature does not appear in the SQL Language Syntax, but is included in the Database Administrator's Guide.

Initializing a member array in constructor initializer

How about

...
  C() : arr{ {1,2,3} }
{}
...

?

Compiles fine on g++ 4.8

Animation CSS3: display + opacity

display: is not transitionable. You'll probably need to use jQuery to do what you want to do.

What is the difference between map and flatMap and a good use case for each?

Use test.md as a example:

?  spark-1.6.1 cat test.md
This is the first line;
This is the second line;
This is the last line.

scala> val textFile = sc.textFile("test.md")
scala> textFile.map(line => line.split(" ")).count()
res2: Long = 3

scala> textFile.flatMap(line => line.split(" ")).count()
res3: Long = 15

scala> textFile.map(line => line.split(" ")).collect()
res0: Array[Array[String]] = Array(Array(This, is, the, first, line;), Array(This, is, the, second, line;), Array(This, is, the, last, line.))

scala> textFile.flatMap(line => line.split(" ")).collect()
res1: Array[String] = Array(This, is, the, first, line;, This, is, the, second, line;, This, is, the, last, line.)

If you use map method, you will get the lines of test.md, for flatMap method, you will get the number of words.

The map method is similar to flatMap, they are all return a new RDD. map method often to use return a new RDD, flatMap method often to use split words.

error: command 'gcc' failed with exit status 1 while installing eventlet

I am using MacOS catalina 10.15.4. None of the posted solutions worked for me. What worked for me is:

 >> xcode-select --install
xcode-select: error: command line tools are already installed, use "Software Update" to install updates

>> env LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib" pip install psycopg2==2.8.4
Collecting psycopg2==2.8.4
  Using cached psycopg2-2.8.4.tar.gz (377 kB)
Installing collected packages: psycopg2
  Attempting uninstall: psycopg2
    Found existing installation: psycopg2 2.7.7
    Uninstalling psycopg2-2.7.7:
      Successfully uninstalled psycopg2-2.7.7
    Running setup.py install for psycopg2 ... done
Successfully installed psycopg2-2.8.4

use pip3 for python3

Keep CMD open after BAT file executes

Depending on how you are running the command, you can put /k after cmd to keep the window open.

cmd /k my_script.bat

Simply adding cmd /k to the end of your batch file will work too. Credit to Luigi D'Amico who posted about this in the comments below.

Change the fill color of a cell based on a selection from a Drop Down List in an adjacent cell

this is the easiest way: Make list
Select list
right click: Define Name (e.g. ItemStatus)
select a cell where the list should appear (copy paste can be done later, so not location critical)
Data > Data Validation
Allow: Select List
Source: =ItemStatus (don't forget the = sign)
click Ok
dropdown appears in the cell you selected
Home > Conditional Formatting
Manage Rules
New Rule
etc.

Use of min and max functions in C++

I would prefer the C++ min/max functions, if you are using C++, because they are type-specific. fmin/fmax will force everything to be converted to/from floating point.

Also, the C++ min/max functions will work with user-defined types as long as you have defined operator< for those types.

HTH

Case insensitive 'in'

My 5 (wrong) cents

'a' in "".join(['A']).lower()

UPDATE

Ouch, totally agree @jpp, I'll keep as an example of bad practice :(

How to list active connections on PostgreSQL?

SELECT * FROM pg_stat_activity WHERE datname = 'dbname' and state = 'active';

Since pg_stat_activity contains connection statistics of all databases having any state, either idle or active, database name and connection state should be included in the query to get the desired output.

Java: how to represent graphs?

class Graph<E> {
    private List<Vertex<E>> vertices;

    private static class Vertex<E> {
        E elem;
        List<Vertex<E>> neighbors;
    }
}

How do you know a variable type in java?

I agree with what Joachim Sauer said, not possible to know (the variable type! not value type!) unless your variable is a class attribute (and you would have to retrieve class fields, get the right field by name...)

Actually for me it's totally impossible that any a.xxx().yyy() method give you the right answer since the answer would be different on the exact same object, according to the context in which you call this method...

As teehoo said, if you know at compile a defined list of types to test you can use instanceof but you will also get subclasses returning true...

One possible solution would also be to inspire yourself from the implementation of java.lang.reflect.Field and create your own Field class, and then declare all your local variables as this custom Field implementation... but you'd better find another solution, i really wonder why you need the variable type, and not just the value type?

Apache won't run in xampp

logout your account in skype.. then in xampp control panel click start from the line of Apache..

Get a Div Value in JQuery

your div looks like this:

<div id="someId">Some Value</div>

With jquery:

   <script type="text/javascript">
     $(function(){
         var text = $('#someId').html(); 
         //or
         var text = $('#someId').text();
       };
  </script> 

Saving binary data as file using JavaScript from a browser

Use FileSaver.js. It supports Chrome, Edge, Firefox, and IE 10+ (and probably IE < 10 with a few "polyfills" - see Note 4). FileSaver.js implements the saveAs() FileSaver interface in browsers that do not natively support it:
     https://github.com/eligrey/FileSaver.js

Minified version is really small at < 2.5KB, gzipped < 1.2KB.

Usage:

/* TODO: replace the blob content with your byte[] */
var blob = new Blob([yourBinaryDataAsAnArrayOrAsAString], {type: "application/octet-stream"});
var fileName = "myFileName.myExtension";
saveAs(blob, fileName);

You might need Blob.js in some browsers (see Note 3). Blob.js implements the W3C Blob interface in browsers that do not natively support it. It is a cross-browser implementation:
     https://github.com/eligrey/Blob.js

Consider StreamSaver.js if you have files larger than blob's size limitations.

Complete example:

_x000D_
_x000D_
/* Two options_x000D_
 * 1. Get FileSaver.js from here_x000D_
 *     https://github.com/eligrey/FileSaver.js/blob/master/FileSaver.min.js -->_x000D_
 *     <script src="FileSaver.min.js" />_x000D_
 *_x000D_
 * Or_x000D_
 *_x000D_
 * 2. If you want to support only modern browsers like Chrome, Edge, Firefox, etc., _x000D_
 *    then a simple implementation of saveAs function can be:_x000D_
 */_x000D_
function saveAs(blob, fileName) {_x000D_
    var url = window.URL.createObjectURL(blob);_x000D_
_x000D_
    var anchorElem = document.createElement("a");_x000D_
    anchorElem.style = "display: none";_x000D_
    anchorElem.href = url;_x000D_
    anchorElem.download = fileName;_x000D_
_x000D_
    document.body.appendChild(anchorElem);_x000D_
    anchorElem.click();_x000D_
_x000D_
    document.body.removeChild(anchorElem);_x000D_
_x000D_
    // On Edge, revokeObjectURL should be called only after_x000D_
    // a.click() has completed, atleast on EdgeHTML 15.15048_x000D_
    setTimeout(function() {_x000D_
        window.URL.revokeObjectURL(url);_x000D_
    }, 1000);_x000D_
}_x000D_
_x000D_
(function() {_x000D_
    // convert base64 string to byte array_x000D_
    var byteCharacters = atob("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");_x000D_
    var byteNumbers = new Array(byteCharacters.length);_x000D_
    for (var i = 0; i < byteCharacters.length; i++) {_x000D_
        byteNumbers[i] = byteCharacters.charCodeAt(i);_x000D_
    }_x000D_
    var byteArray = new Uint8Array(byteNumbers);_x000D_
    _x000D_
    // now that we have the byte array, construct the blob from it_x000D_
    var blob1 = new Blob([byteArray], {type: "application/octet-stream"});_x000D_
_x000D_
    var fileName1 = "cool.gif";_x000D_
    saveAs(blob1, fileName1);_x000D_
_x000D_
    // saving text file_x000D_
    var blob2 = new Blob(["cool"], {type: "text/plain"});_x000D_
    var fileName2 = "cool.txt";_x000D_
    saveAs(blob2, fileName2);_x000D_
})();
_x000D_
_x000D_
_x000D_


Tested on Chrome, Edge, Firefox, and IE 11 (use FileSaver.js for supporting IE 11).
You can also save from a canvas element. See https://github.com/eligrey/FileSaver.js#saving-a-canvas.

Demos: https://eligrey.com/demos/FileSaver.js/

Blog post by author of FileSaver.js: http://eligrey.com/blog/post/saving-generated-files-on-the-client-side

Note 1: Browser support: https://github.com/eligrey/FileSaver.js#supported-browsers

Note 2: Failed to execute 'atob' on 'Window'

Note 3: Polyfill for browsers not supporting Blob: https://github.com/eligrey/Blob.js
                See http://caniuse.com/#search=blob

Note 4: IE < 10 support (I've not tested this part):
                https://github.com/eligrey/FileSaver.js#ie--10
                https://github.com/eligrey/FileSaver.js/issues/56#issuecomment-30917476

Downloadify is a Flash-based polyfill for supporting IE6-9: https://github.com/dcneiner/downloadify (I don't recommend Flash-based solutions in general, though.)
Demo using Downloadify and FileSaver.js for supporting IE6-9 also: http://sheetjs.com/demos/table.html

Note 5: Creating a BLOB from a Base64 string in JavaScript

Note 6: FileSaver.js examples: https://github.com/eligrey/FileSaver.js#examples

Download all stock symbol list of a market

Exchanges will usually publish an up-to-date list of securities on their web pages. For example, these pages offer CSV downloads:

NASDAQ Updated their site, so you will have to modify the URLS:

NASDAQ

AMEX

NYSE

Depending on your requirement, you could create the map of these URLs by exchange in your own code.

How to copy an object by value, not by reference

what language is this? If you're using a language that passes everything by reference like Java (except for native types), typically you can call .clone() method. The .clone() method is typically implemented by copying/cloning all relevant instance fields into the new object.

ValidateAntiForgeryToken purpose, explanation and example

MVC's anti-forgery support writes a unique value to an HTTP-only cookie and then the same value is written to the form. When the page is submitted, an error is raised if the cookie value doesn't match the form value.

It's important to note that the feature prevents cross site request forgeries. That is, a form from another site that posts to your site in an attempt to submit hidden content using an authenticated user's credentials. The attack involves tricking the logged in user into submitting a form, or by simply programmatically triggering a form when the page loads.

The feature doesn't prevent any other type of data forgery or tampering based attacks.

To use it, decorate the action method or controller with the ValidateAntiForgeryToken attribute and place a call to @Html.AntiForgeryToken() in the forms posting to the method.

Limitations of SQL Server Express

If you switch from Web to Express you will no longer be able to use the SQL Server Agent service so you need to set up a different scheduler for maintenance and backups.

Select method in List<t> Collection

Generic List<T> have the Where<T>(Func<T, Boolean>) extension method that can be used to filter data.

In your case with a row array:

var rows = rowsArray.Where(row => row["LastName"].ToString().StartsWith("a"));

If you are using DataRowCollection, you need to cast it first.

var rows = dataTableRows.Cast<DataRow>().Where(row => row["LastName"].ToString().StartsWith("a"));

How to hide TabPage from TabControl

private System.Windows.Forms.TabControl _tabControl;
private System.Windows.Forms.TabPage _tabPage1;
private System.Windows.Forms.TabPage _tabPage2;

...
// Initialise the controls
...

// "hides" tab page 2
_tabControl.TabPages.Remove(_tabPage2);

// "shows" tab page 2
// if the tab control does not contain tabpage2
if (! _tabControl.TabPages.Contains(_tabPage2))
{
    _tabControl.TabPages.Add(_tabPage2);
}

How can I scroll a web page using selenium webdriver in python?

if you want to scroll within a particular view/frame (WebElement), what you only need to do is to replace "body" with a particular element that you intend to scroll within. i get that element via "getElementById" in the example below:

self.driver.execute_script('window.scrollTo(0, document.getElementById("page-manager").scrollHeight);')

this is the case on YouTube, for example...

Parse error: Syntax error, unexpected end of file in my PHP code

I developed a plugin and installed it on a Wordpress site running on Nginx and it was fine. I only had this error when I switched to Apache, turned out the web server was not accepting the <?, so I just replaced the <? tags to <?php then it worked.

Remove spaces from std::string in C++

From gamedev

string.erase(std::remove_if(string.begin(), string.end(), std::isspace), string.end());

VBA Macro to compare all cells of two Excel files

Do NOT loop through all cells!! There is a lot of overhead in communications between worksheets and VBA, for both reading and writing. Looping through all cells will be agonizingly slow. I'm talking hours.

Instead, load an entire sheet at once into a Variant array. In Excel 2003, this takes about 2 seconds (and 250 MB of RAM). Then you can loop through it in no time at all.

In Excel 2007 and later, sheets are about 1000 times larger (1048576 rows × 16384 columns = 17 billion cells, compared to 65536 rows × 256 columns = 17 million in Excel 2003). You will run into an "Out of memory" error if you try to load the whole sheet into a Variant; on my machine I can only load 32 million cells at once. So you have to limit yourself to the range you know has actual data in it, or load the sheet bit by bit, e.g. 30 columns at a time.

Option Explicit

Sub test()

    Dim varSheetA As Variant
    Dim varSheetB As Variant
    Dim strRangeToCheck As String
    Dim iRow As Long
    Dim iCol As Long

    strRangeToCheck = "A1:IV65536"
    ' If you know the data will only be in a smaller range, reduce the size of the ranges above.
    Debug.Print Now
    varSheetA = Worksheets("Sheet1").Range(strRangeToCheck)
    varSheetB = Worksheets("Sheet2").Range(strRangeToCheck) ' or whatever your other sheet is.
    Debug.Print Now

    For iRow = LBound(varSheetA, 1) To UBound(varSheetA, 1)
        For iCol = LBound(varSheetA, 2) To UBound(varSheetA, 2)
            If varSheetA(iRow, iCol) = varSheetB(iRow, iCol) Then
                ' Cells are identical.
                ' Do nothing.
            Else
                ' Cells are different.
                ' Code goes here for whatever it is you want to do.
            End If
        Next iCol
    Next iRow

End Sub

To compare to a sheet in a different workbook, open that workbook and get the sheet as follows:

Set wbkA = Workbooks.Open(filename:="C:\MyBook.xls")
Set varSheetA = wbkA.Worksheets("Sheet1") ' or whatever sheet you need

Skip download if files exist in wget?

The -nc, --no-clobber option isn't the best solution as newer files will not be downloaded. One should use -N instead which will download and overwrite the file only if the server has a newer version, so the correct answer is:

wget -N http://www.example.com/images/misc/pic.png

Then running Wget with -N, with or without -r or -p, the decision as to whether or not to download a newer copy of a file depends on the local and remote timestamp and size of the file. -nc may not be specified at the same time as -N.

-N, --timestamping: Turn on time-stamping.

jQuery select change show/hide div event

Try this:

 $(function () {
     $('#row_dim').hide(); // this line you can avoid by adding #row_dim{display:none;} in your CSS
     $('#type').change(function () {
         $('#row_dim').hide();
         if (this.options[this.selectedIndex].value == 'parcel') {
             $('#row_dim').show();
         }
     });
 });

Demo here

INSERT SELECT statement in Oracle 11G

There is an another option to insert data into table ..

insert into tablename values(&column_name1,&column_name2,&column_name3);

it will open another window for inserting the data value..

Where does flask look for image files?

From the documentation:

Dynamic web applications also need static files. That’s usually where the CSS and JavaScript files are coming from. Ideally your web server is configured to serve them for you, but during development Flask can do that as well. Just create a folder called static in your package or next to your module and it will be available at /static on the application.

To generate URLs for static files, use the special 'static' endpoint name:

url_for('static', filename='style.css')

The file has to be stored on the filesystem as static/style.css.

Simple way to encode a string according to a password?

An other implementation of @qneill code which include CRC checksum of the original message, it throw an exception if the check fail:

import hashlib
import struct
import zlib

def vigenere_encode(text, key):
    text = '{}{}'.format(text, struct.pack('i', zlib.crc32(text)))

    enc = []
    for i in range(len(text)):
        key_c = key[i % len(key)]
        enc_c = chr((ord(text[i]) + ord(key_c)) % 256)
        enc.append(enc_c)

    return base64.urlsafe_b64encode("".join(enc))


def vigenere_decode(encoded_text, key):
    dec = []
    encoded_text = base64.urlsafe_b64decode(encoded_text)
    for i in range(len(encoded_text)):
        key_c = key[i % len(key)]
        dec_c = chr((256 + ord(encoded_text[i]) - ord(key_c)) % 256)
        dec.append(dec_c)

    dec = "".join(dec)
    checksum = dec[-4:]
    dec = dec[:-4]

    assert zlib.crc32(dec) == struct.unpack('i', checksum)[0], 'Decode Checksum Error'

    return dec

How to close a JavaFX application on window close?

Some of the provided answers did not work for me (javaw.exe still running after closing the window) or, eclipse showed an exception after the application was closed.

On the other hand, this works perfectly:

primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() {
    @Override
    public void handle(WindowEvent t) {
        Platform.exit();
        System.exit(0);
    }
});

Find commit by hash SHA in Git

Just use the following command

git show a2c25061

or (the exact equivalent):

git log -p -1 a2c25061

Create a string of variable length, filled with a repeated character

Give this a try :P

_x000D_
_x000D_
s = '#'.repeat(10)_x000D_
_x000D_
document.body.innerHTML = s
_x000D_
_x000D_
_x000D_

Cannot connect to local SQL Server with Management Studio

Same as matt said. The "SQL Server(SQLEXPRESS)" was stopped. Enabled it by opening Control Panel > Administrative Tools > Services, right-clicking on the "SQL Server(SQLEXPRESS)" service and selecting "Start" from the available options. Could connect fine after that.

DateTime "null" value

I'd consider using a nullable types.

DateTime? myDate instead of DateTime myDate.

SQL exclude a column using SELECT * [except columnA] FROM tableA?

Sometimes the same program must handle different database stuctures. So I could not use a column list in the program to avoid errors in select statements.

* gives me all the optional fields. I check if the fields exist in the data table before use. This is my reason for using * in select.

This is how I handle excluded fields:

Dim da As New SqlDataAdapter("select * from table", cn)
da.FillSchema(dt, SchemaType.Source)
Dim fieldlist As String = ""
For Each DC As DataColumn In DT.Columns
   If DC.ColumnName.ToLower <> excludefield Then
    fieldlist = fieldlist &  DC.Columnname & ","
   End If
  Next

How to count the number of occurrences of a character in an Oracle varchar value?

REGEXP_COUNT should do the trick:

select REGEXP_COUNT('123-345-566', '-') from dual;

How to download videos from youtube on java?

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogRecord;
import java.util.logging.Logger;
import java.util.regex.Pattern;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.CookieStore;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.protocol.ClientContext;
import org.apache.http.client.utils.URIUtils;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.BasicCookieStore;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;

public class JavaYoutubeDownloader {

 public static String newline = System.getProperty("line.separator");
 private static final Logger log = Logger.getLogger(JavaYoutubeDownloader.class.getCanonicalName());
 private static final Level defaultLogLevelSelf = Level.FINER;
 private static final Level defaultLogLevel = Level.WARNING;
 private static final Logger rootlog = Logger.getLogger("");
 private static final String scheme = "http";
 private static final String host = "www.youtube.com";
 private static final Pattern commaPattern = Pattern.compile(",");
 private static final Pattern pipePattern = Pattern.compile("\\|");
 private static final char[] ILLEGAL_FILENAME_CHARACTERS = { '/', '\n', '\r', '\t', '\0', '\f', '`', '?', '*', '\\', '<', '>', '|', '\"', ':' };

 private static void usage(String error) {
  if (error != null) {
   System.err.println("Error: " + error);
  }
  System.err.println("usage: JavaYoutubeDownload VIDEO_ID DESTINATION_DIRECTORY");
  System.exit(-1);
 }

 public static void main(String[] args) {
  if (args == null || args.length == 0) {
   usage("Missing video id. Extract from http://www.youtube.com/watch?v=VIDEO_ID");
  }
  try {
   setupLogging();

   log.fine("Starting");
   String videoId = null;
   String outdir = ".";
   // TODO Ghetto command line parsing
   if (args.length == 1) {
    videoId = args[0];
   } else if (args.length == 2) {
    videoId = args[0];
    outdir = args[1];
   }

   int format = 18; // http://en.wikipedia.org/wiki/YouTube#Quality_and_codecs
   String encoding = "UTF-8";
   String userAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13";
   File outputDir = new File(outdir);
   String extension = getExtension(format);

   play(videoId, format, encoding, userAgent, outputDir, extension);

  } catch (Throwable t) {
   t.printStackTrace();
  }
  log.fine("Finished");
 }

 private static String getExtension(int format) {
  // TODO
  return "mp4";
 }

 private static void play(String videoId, int format, String encoding, String userAgent, File outputdir, String extension) throws Throwable {
  log.fine("Retrieving " + videoId);
  List<NameValuePair> qparams = new ArrayList<NameValuePair>();
  qparams.add(new BasicNameValuePair("video_id", videoId));
  qparams.add(new BasicNameValuePair("fmt", "" + format));
  URI uri = getUri("get_video_info", qparams);

  CookieStore cookieStore = new BasicCookieStore();
  HttpContext localContext = new BasicHttpContext();
  localContext.setAttribute(ClientContext.COOKIE_STORE, cookieStore);

  HttpClient httpclient = new DefaultHttpClient();
  HttpGet httpget = new HttpGet(uri);
  httpget.setHeader("User-Agent", userAgent);

  log.finer("Executing " + uri);
  HttpResponse response = httpclient.execute(httpget, localContext);
  HttpEntity entity = response.getEntity();
  if (entity != null && response.getStatusLine().getStatusCode() == 200) {
   InputStream instream = entity.getContent();
   String videoInfo = getStringFromInputStream(encoding, instream);
   if (videoInfo != null && videoInfo.length() > 0) {
    List<NameValuePair> infoMap = new ArrayList<NameValuePair>();
    URLEncodedUtils.parse(infoMap, new Scanner(videoInfo), encoding);
    String token = null;
    String downloadUrl = null;
    String filename = videoId;

    for (NameValuePair pair : infoMap) {
     String key = pair.getName();
     String val = pair.getValue();
     log.finest(key + "=" + val);
     if (key.equals("token")) {
      token = val;
     } else if (key.equals("title")) {
      filename = val;
     } else if (key.equals("fmt_url_map")) {
      String[] formats = commaPattern.split(val);
      for (String fmt : formats) {
       String[] fmtPieces = pipePattern.split(fmt);
       if (fmtPieces.length == 2) {
        // in the end, download somethin!
        downloadUrl = fmtPieces[1];
        int pieceFormat = Integer.parseInt(fmtPieces[0]);
        if (pieceFormat == format) {
         // found what we want
         downloadUrl = fmtPieces[1];
         break;
        }
       }
      }
     }
    }

    filename = cleanFilename(filename);
    if (filename.length() == 0) {
     filename = videoId;
    } else {
     filename += "_" + videoId;
    }
    filename += "." + extension;
    File outputfile = new File(outputdir, filename);

    if (downloadUrl != null) {
     downloadWithHttpClient(userAgent, downloadUrl, outputfile);
    }
   }
  }
 }

 private static void downloadWithHttpClient(String userAgent, String downloadUrl, File outputfile) throws Throwable {
  HttpGet httpget2 = new HttpGet(downloadUrl);
  httpget2.setHeader("User-Agent", userAgent);

  log.finer("Executing " + httpget2.getURI());
  HttpClient httpclient2 = new DefaultHttpClient();
  HttpResponse response2 = httpclient2.execute(httpget2);
  HttpEntity entity2 = response2.getEntity();
  if (entity2 != null && response2.getStatusLine().getStatusCode() == 200) {
   long length = entity2.getContentLength();
   InputStream instream2 = entity2.getContent();
   log.finer("Writing " + length + " bytes to " + outputfile);
   if (outputfile.exists()) {
    outputfile.delete();
   }
   FileOutputStream outstream = new FileOutputStream(outputfile);
   try {
    byte[] buffer = new byte[2048];
    int count = -1;
    while ((count = instream2.read(buffer)) != -1) {
     outstream.write(buffer, 0, count);
    }
    outstream.flush();
   } finally {
    outstream.close();
   }
  }
 }

 private static String cleanFilename(String filename) {
  for (char c : ILLEGAL_FILENAME_CHARACTERS) {
   filename = filename.replace(c, '_');
  }
  return filename;
 }

 private static URI getUri(String path, List<NameValuePair> qparams) throws URISyntaxException {
  URI uri = URIUtils.createURI(scheme, host, -1, "/" + path, URLEncodedUtils.format(qparams, "UTF-8"), null);
  return uri;
 }

 private static void setupLogging() {
  changeFormatter(new Formatter() {
   @Override
   public String format(LogRecord arg0) {
    return arg0.getMessage() + newline;
   }
  });
  explicitlySetAllLogging(Level.FINER);
 }

 private static void changeFormatter(Formatter formatter) {
  Handler[] handlers = rootlog.getHandlers();
  for (Handler handler : handlers) {
   handler.setFormatter(formatter);
  }
 }

 private static void explicitlySetAllLogging(Level level) {
  rootlog.setLevel(Level.ALL);
  for (Handler handler : rootlog.getHandlers()) {
   handler.setLevel(defaultLogLevelSelf);
  }
  log.setLevel(level);
  rootlog.setLevel(defaultLogLevel);
 }

 private static String getStringFromInputStream(String encoding, InputStream instream) throws UnsupportedEncodingException, IOException {
  Writer writer = new StringWriter();

  char[] buffer = new char[1024];
  try {
   Reader reader = new BufferedReader(new InputStreamReader(instream, encoding));
   int n;
   while ((n = reader.read(buffer)) != -1) {
    writer.write(buffer, 0, n);
   }
  } finally {
   instream.close();
  }
  String result = writer.toString();
  return result;
 }
}

/**
 * <pre>
 * Exploded results from get_video_info:
 * 
 * fexp=90...
 * allow_embed=1
 * fmt_stream_map=35|http://v9.lscache8...
 * fmt_url_map=35|http://v9.lscache8...
 * allow_ratings=1
 * keywords=Stefan Molyneux,Luke Bessey,anarchy,stateless society,giant stone cow,the story of our unenslavement,market anarchy,voluntaryism,anarcho capitalism
 * track_embed=0
 * fmt_list=35/854x480/9/0/115,34/640x360/9/0/115,18/640x360/9/0/115,5/320x240/7/0/0
 * author=lukebessey
 * muted=0
 * length_seconds=390
 * plid=AA...
 * ftoken=null
 * status=ok
 * watermark=http://s.ytimg.com/yt/swf/logo-vfl_bP6ud.swf,http://s.ytimg.com/yt/swf/hdlogo-vfloR6wva.swf
 * timestamp=12...
 * has_cc=False
 * fmt_map=35/854x480/9/0/115,34/640x360/9/0/115,18/640x360/9/0/115,5/320x240/7/0/0
 * leanback_module=http://s.ytimg.com/yt/swfbin/leanback_module-vflJYyeZN.swf
 * hl=en_US
 * endscreen_module=http://s.ytimg.com/yt/swfbin/endscreen-vflk19iTq.swf
 * vq=auto
 * avg_rating=5.0
 * video_id=S6IZP3yRJ9I
 * token=vPpcFNh...
 * thumbnail_url=http://i4.ytimg.com/vi/S6IZP3yRJ9I/default.jpg
 * title=The Story of Our Unenslavement - Animated
 * </pre>
 */

Post Build exited with code 1

The one with the "Pings" helped me... but may be explained a little better...

For me the solution was to change:

copy $(TargetDir)$(TargetName).* $(SolutionDir)bin

to this:

copy "$(TargetDir)$(TargetName).*" "$(SolutionDir)bin"

Hope it works for you. :-)

matplotlib get ylim values

It's an old question, but I don't see mentioned that, depending on the details, the sharey option may be able to do all of this for you, instead of digging up axis limits, margins, etc. There's a demo in the docs that shows how to use sharex, but the same can be done with y-axes.

IIS: Display all sites and bindings in PowerShell

If you just want to list all the sites (ie. to find a binding)

Change the working directory to "C:\Windows\system32\inetsrv"

cd c:\Windows\system32\inetsrv

Next run "appcmd list sites" (plural) and output to a file. e.g c:\IISSiteBindings.txt

appcmd list sites > c:\IISSiteBindings.txt

Now open with notepad from your command prompt.

notepad c:\IISSiteBindings.txt

Apply CSS rules to a nested class inside a div

Use Css Selector for this, or learn more about Css Selector just go here https://www.w3schools.com/cssref/css_selectors.asp

#main_text > .title {
  /* Style goes here */
}

#main_text .title {
  /* Style goes here */
}

Java better way to delete file if exists

Use Apache Commons FileUtils.deleteDirectory() or FileUtils.forceDelete() to log exceptions in case of any failures,

or FileUtils.deleteQuietly() if you're not concerned about exceptions thrown.

Excel Reference To Current Cell

=ADDRESS(ROW(),COLUMN())
=ADDRESS(ROW(),COLUMN(),1)
=ADDRESS(ROW(),COLUMN(),2)
=ADDRESS(ROW(),COLUMN(),3)
=ADDRESS(ROW(),COLUMN(),4)

jQuery creating objects

Another way to make objects in Javascript using JQuery, getting data from the dom and pass it to the object Box and, for example, store them in an array of Boxes, could be:

var box = {}; // my object
var boxes =  []; // my array

$('div.test').each(function (index, value) {
    color = $('p', this).attr('color');
    box = {
        _color: color // being _color a property of `box`
    }
    boxes.push(box);
});

Hope it helps!

Arduino IDE can't find ESP8266WiFi.h file

Starting with 1.6.4, Arduino IDE can be used to program and upload the NodeMCU board by installing the ESP8266 third-party platform package (refer https://github.com/esp8266/Arduino):

  • Start Arduino, go to File > Preferences
  • Add the following link to the Additional Boards Manager URLs: http://arduino.esp8266.com/stable/package_esp8266com_index.json and press OK button
  • Click Tools > Boards menu > Boards Manager, search for ESP8266 and install ESP8266 platform from ESP8266 community (and don't forget to select your ESP8266 boards from Tools > Boards menu after installation)

To install additional ESP8266WiFi library:

  • Click Sketch > Include Library > Manage Libraries, search for ESP8266WiFi and then install with the latest version.

After above steps, you should compile the sketch normally.

Clear text field value in JQuery

$('#[element id]').val(null);

or

$('.[element class]').val(null);

Running command line silently with VbScript and getting output?

Look for assigning the output to Clipboard (in your first script) and then in second script parse Clipboard value.

starting file download with JavaScript

In relation to the top answer I have a possible solution to the security risk.

<?php
     if(isset($_GET['path'])){
         if(in_array($_GET['path'], glob("*/*.*"))){
             header("Content-Type: application/octet-stream");
             header("Content-Disposition: attachment; filename=".$_GET['path']);
             readfile($_GET['path']);
         }
     }
?>

Using the glob() function (I tested the download file in a path one folder up from the file to be downloaded) I was able to make a quick array of files that are "allowed" to be downloaded and checked the passed path against it. Not only does this insure that the file being grabbed isn't something sensitive but also checks on the files existence at the same time.

~Note: Javascript / HTML~

HTML:

<iframe id="download" style="display:none"></iframe>

and

<input type="submit" value="Download" onclick="ChangeSource('document_path');return false;">

JavaScript:

<script type="text/javascript">
    <!--
        function ChangeSource(path){
            document.getElementByID('download').src = 'path_to_php?path=' + document_path;
        }
    -->
</script>

Error: Cannot find module 'webpack'

I was having this issue on OS X and it seemed to be caused by a version mismatch between my globally installed webpack and my locally installed webpack-dev-server. Updating both to the latest version got rid of the issue.

Read .csv file in C

Hopefully this would get you started

See it live on http://ideone.com/l23He (using stdin)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

const char* getfield(char* line, int num)
{
    const char* tok;
    for (tok = strtok(line, ";");
            tok && *tok;
            tok = strtok(NULL, ";\n"))
    {
        if (!--num)
            return tok;
    }
    return NULL;
}

int main()
{
    FILE* stream = fopen("input", "r");

    char line[1024];
    while (fgets(line, 1024, stream))
    {
        char* tmp = strdup(line);
        printf("Field 3 would be %s\n", getfield(tmp, 3));
        // NOTE strtok clobbers tmp
        free(tmp);
    }
}

Output:

Field 3 would be nazwisko
Field 3 would be Kowalski
Field 3 would be Nowak

Can a unit test project load the target application's app.config file?

The simplest way to do this is to add the .config file in the deployment section on your unit test.

To do so, open the .testrunconfig file from your Solution Items. In the Deployment section, add the output .config files from your project's build directory (presumably bin\Debug).

Anything listed in the deployment section will be copied into the test project's working folder before the tests are run, so your config-dependent code will run fine.

Edit: I forgot to add, this will not work in all situations, so you may need to include a startup script that renames the output .config to match the unit test's name.

angular.js ng-repeat li items with html content

It goes like ng-bind-html-unsafe="opt.text":

<div ng-app ng-controller="MyCtrl">
    <ul>
    <li ng-repeat=" opt in opts" ng-bind-html-unsafe="opt.text" >
        {{ opt.text }}
    </li>
    </ul>

    <p>{{opt}}</p>
</div>

http://jsfiddle.net/gFFBa/3/

Or you can define a function in scope:

 $scope.getContent = function(obj){
     return obj.value + " " + obj.text;
 }

And use it this way:

<li ng-repeat=" opt in opts" ng-bind-html-unsafe="getContent(opt)" >
     {{ opt.value }}
</li>

http://jsfiddle.net/gFFBa/4/

Note that you can not do it with an option tag: Can I use HTML tags in the options for select elements?

How to get all columns' names for all the tables in MySQL?

<?php
        $table = 'orders';
        $query = "SHOW COLUMNS FROM $table";
        if($output = mysql_query($query)):
            $columns = array();
            while($result = mysql_fetch_assoc($output)):
                $columns[] = $result['Field'];
            endwhile;
        endif;
        echo '<pre>';
        print_r($columns);
        echo '</pre>';
?>

Creating an iframe with given HTML dynamically

The URL approach will only work for small HTML fragements. The more solid approach is to generate an object URL from a blob and use it as a source of the dynamic iframe.

const html = '<html>...</html>';
const iframe = document.createElement('iframe');
const blob = new Blob([html], {type: 'text/html'});
iframe.src = window.URL.createObjectURL(blob);
document.body.appendChild(iframe);

how to enable sqlite3 for php?

For PHP7, use

sudo apt-get install php7.0-sqlite3

and restart Apache

sudo apache2ctl restart

Proper way to set response status and JSON content in a REST API made with nodejs and express

You could do it this way:

res.status(400).json(json_response);

This will set the HTTP status code to 400, it works even in express 4.

How to pass variable number of arguments to a PHP function

You can just call it.

function test(){        
     print_r(func_get_args());
}

test("blah");
test("blah","blah");

Output:

Array ( [0] => blah ) Array ( [0] => blah [1] => blah )

How to unsubscribe to a broadcast event in angularJS. How to remove function registered via $on

This code works for me:

$rootScope.$$listeners.nameOfYourEvent=[];

How can I delete one element from an array by value

Assuming you want to delete 3 by value at multiple places in an array, I think the ruby way to do this task would be to use the delete_if method:

[2,4,6,3,8,3].delete_if {|x| x == 3 } 

You can also use delete_if in removing elements in the scenario of 'array of arrays'.

Hope this resolves your query

jQuery $(".class").click(); - multiple elements, click event once

Hi sorry for bump this post just face this problem and i would like to show my case.

My code look like this.

<button onClick="product.delete('1')" class="btn btn-danger">Delete</button>
<button onClick="product.delete('2')" class="btn btn-danger">Delete</button>
<button onClick="product.delete('3')" class="btn btn-danger">Delete</button>
<button onClick="product.delete('4')" class="btn btn-danger">Delete</button>

Javascript code

<script>
 var product = {
     //  Define your function
     'add':(product_id)=>{
          //  Do some thing here
     },

     'delete':(product_id)=>{
         //  Do some thig here
     }
 }
</script>

How to print variables in Perl

print "Number of lines: $nids\n";
print "Content: $ids\n";

How did Perl complain? print $ids should work, though you probably want a newline at the end, either explicitly with print as above or implicitly by using say or -l/$\.

If you want to interpolate a variable in a string and have something immediately after it that would looks like part of the variable but isn't, enclose the variable name in {}:

print "foo${ids}bar";

How to recover a dropped stash in Git?

I just constructed a command that helped me find my lost stash commit:

for ref in `find .git/objects | sed -e 's#.git/objects/##' | grep / | tr -d /`; do if [ `git cat-file -t $ref` = "commit" ]; then git show --summary $ref; fi; done | less

This lists all the objects in the .git/objects tree, locates the ones that are of type commit, then shows a summary of each one. From this point it was just a matter of looking through the commits to find an appropriate "WIP on work: 6a9bb2" ("work" is my branch, 619bb2 is a recent commit).

I note that if I use "git stash apply" instead of "git stash pop" I wouldn't have this problem, and if I use "git stash save message" then the commit might have been easier to find.

Update: With Nathan's idea, this becomes shorter:

for ref in `git fsck --unreachable | grep commit | cut -d' ' -f3`; do git show --summary $ref; done | less

How to change menu item text dynamically in Android

Create a setOptionsTitle() method and set a field in your class. Such as:

String bedStatus = "Set to 'Out of Bed'";

...

public void setOptionsTitle(String status)
{
    bedStatus = status;

}

Now when the menu gets populated, change the title to whatever your status is:

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);

        menu.add(bedStatus);


        // Return true so that the menu gets displayed.
        return true;
    }

Is it possible to run JavaFX applications on iOS, Android or Windows Phone 8?

Desktop: first-class support

Oracle JavaFX from Java SE supports only OS X (macOS), GNU/Linux and Microsoft Windows. On these platforms, JavaFX applications are typically run on JVM from Java SE or OpenJDK.

Android: should work

There is also a JavaFXPorts project, which is an open-source project sponsored by a third-party. It aims to port JavaFX library to Android and iOS.

On Android, this library can be used like any other Java library; the JVM bytecode is compiled to Dalvik bytecode. It's what people mean by saying that "Android runs Java".

iOS: status not clear

On iOS, situation is a bit more complex, as neither Java SE nor OpenJDK supports Apple mobile devices. Till recently, the only sensible option was to use RoboVM ahead-of-time Java compiler for iOS. Unfortunately, on 15 April 2015, RoboVM project was shut down.

One possible alternative is Intel's Multi-OS Engine. Till recently, it was a proprietary technology, but on 11 August 2016 it was open-sourced. Although it can be possible to compile an iOS JavaFX app using JavaFXPorts' JavaFX implementation, there is no evidence for that so far. As you can see, the situation is dynamically changing, and this answer will be hopefully updated when new information is available.

Windows Phone: no support

With Windows Phone it's simple: there is no JavaFX support of any kind.

How to check if a variable is an integer or a string?

The isdigit method of the str type returns True iff the given string is nothing but one or more digits. If it's not, you know the string should be treated as just a string.

JavaScript for detecting browser language preference

There is no decent way to get that setting, at least not something browser independent.

But the server has that info, because it is part of the HTTP request header (the Accept-Language field, see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4)

So the only reliable way is to get an answer back from the server. You will need something that runs on the server (like .asp, .jsp, .php, CGI) and that "thing" can return that info. Good examples here: http://www.developershome.com/wap/detection/detection.asp?page=readHeader

No Main class found in NetBeans

You need to rename your main class to Main, it cannot be anything else.

It does not matter how many files as packages and classes you create, you must name your main class Main.

That's all.

How to set a background image in Xcode using swift?

I am beginner to iOS development so I would like to share whole info I got in this section.

First from image assets (images.xcassets) create image set .

According to Documentation here is all sizes need to create background image.

For iPhone 5:
   640 x 1136

   For iPhone 6:
   750 x 1334 (@2x) for portrait
   1334 x 750 (@2x) for landscape

   For iPhone 6 Plus:
   1242 x 2208 (@3x) for portrait
   2208 x 1242 (@3x) for landscape

   iPhone 4s (@2x)      
   640 x 960

   iPad and iPad mini (@2x) 
   1536 x 2048 (portrait)
   2048 x 1536 (landscape)

   iPad 2 and iPad mini (@1x)
   768 x 1024 (portrait)
   1024 x 768 (landscape)

   iPad Pro (@2x)
   2048 x 2732 (portrait)
   2732 x 2048 (landscape)

call the image background we can call image from image assets by using this method UIImage(named: "background") here is full code example

  override func viewDidLoad() {
          super.viewDidLoad()
             assignbackground()
            // Do any additional setup after loading the view.
        }

  func assignbackground(){
        let background = UIImage(named: "background")

        var imageView : UIImageView!
        imageView = UIImageView(frame: view.bounds)
        imageView.contentMode =  UIViewContentMode.ScaleAspectFill
        imageView.clipsToBounds = true
        imageView.image = background
        imageView.center = view.center
        view.addSubview(imageView)
        self.view.sendSubviewToBack(imageView)
    }

Git add all files modified, deleted, and untracked?

I authored the G2 project, a friendly environment for the command line git lover.
Please get the project from github - G2 https://github.com/orefalo/g2

It has a bunch of handy commands, one of them being exactly what your are looking for: freeze

freeze - Freeze all files in the repository (additions, deletions, modifications) to the staging area, thus staging that content for inclusion in the next commit. Also accept a specific path as parameter

How to start activity in another application?

If you guys are facing "Permission Denial: starting Intent..." error or if the app is getting crash without any reason during launching the app - Then use this single line code in Manifest

android:exported="true"

Please be careful with finish(); , if you missed out it the app getting frozen. if its mentioned the app would be a smooth launcher.

finish();

The other solution only works for two activities that are in the same application. In my case, application B doesn't know class com.example.MyExampleActivity.class in the code, so compile will fail.

I searched on the web and found something like this below, and it works well.

Intent intent = new Intent();
intent.setComponent(new ComponentName("com.example", "com.example.MyExampleActivity"));
startActivity(intent);

You can also use the setClassName method:

Intent intent = new Intent(Intent.ACTION_MAIN);
intent.setClassName("com.hotfoot.rapid.adani.wheeler.android", "com.hotfoot.rapid.adani.wheeler.android.view.activities.MainActivity");
startActivity(intent);
finish();

You can also pass the values from one app to another app :

Intent launchIntent = getApplicationContext().getPackageManager().getLaunchIntentForPackage("com.hotfoot.rapid.adani.wheeler.android.LoginActivity");
if (launchIntent != null) {
    launchIntent.putExtra("AppID", "MY-CHILD-APP1");
    launchIntent.putExtra("UserID", "MY-APP");
    launchIntent.putExtra("Password", "MY-PASSWORD");
    startActivity(launchIntent);
    finish();
} else {
    Toast.makeText(getApplicationContext(), " launch Intent not available", Toast.LENGTH_SHORT).show();
}

DropdownList DataSource

Refer to example at this link. It may be help to you.

http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.dropdownlist.aspx

void Page_Load(Object sender, EventArgs e)
  {

     // Load data for the DropDownList control only once, when the 
     // page is first loaded.
     if(!IsPostBack)
     {

        // Specify the data source and field names for the Text 
        // and Value properties of the items (ListItem objects) 
        // in the DropDownList control.
        ColorList.DataSource = CreateDataSource();
        ColorList.DataTextField = "ColorTextField";
        ColorList.DataValueField = "ColorValueField";

        // Bind the data to the control.
        ColorList.DataBind();

        // Set the default selected item, if desired.
        ColorList.SelectedIndex = 0;

     }

  }

void Selection_Change(Object sender, EventArgs e)
  {

     // Set the background color for days in the Calendar control
     // based on the value selected by the user from the 
     // DropDownList control.
     Calendar1.DayStyle.BackColor = 
         System.Drawing.Color.FromName(ColorList.SelectedItem.Value);

  }

How do I get a consistent byte representation of strings in C# without manually specifying an encoding?

bytes[] buffer = UnicodeEncoding.UTF8.GetBytes(string something); //for converting to UTF then get its bytes

bytes[] buffer = ASCIIEncoding.ASCII.GetBytes(string something); //for converting to ascii then get its bytes

What is the Java equivalent of PHP var_dump?

Your alternatives are to override the toString() method of your object to output its contents in a way that you like, or to use reflection to inspect the object (in a way similar to what debuggers do).

The advantage of using reflection is that you won't need to modify your individual objects to be "analysable", but there is added complexity and if you need nested object support you'll have to write that.

This code will list the fields and their values for an Object "o"

Field[] fields = o.getClass().getDeclaredFields();
for (int i=0; i<fields.length; i++)
{
    System.out.println(fields[i].getName() + " - " + fields[i].get(o));
}

Base64 encoding and decoding in client-side Javascript

For what it's worth, I got inspired by the other answers and wrote a small utility which calls the platform specific APIs to be used universally from either Node.js or a browser:

_x000D_
_x000D_
/**
 * Encode a string of text as base64
 *
 * @param data The string of text.
 * @returns The base64 encoded string.
 */
function encodeBase64(data: string) {
    if (typeof btoa === "function") {
        return btoa(data);
    } else if (typeof Buffer === "function") {
        return Buffer.from(data, "utf-8").toString("base64");
    } else {
        throw new Error("Failed to determine the platform specific encoder");
    }
}

/**
 * Decode a string of base64 as text
 *
 * @param data The string of base64 encoded text
 * @returns The decoded text.
 */
function decodeBase64(data: string) {
    if (typeof atob === "function") {
        return atob(data);
    } else if (typeof Buffer === "function") {
        return Buffer.from(data, "base64").toString("utf-8");
    } else {
        throw new Error("Failed to determine the platform specific decoder");
    }
}
_x000D_
_x000D_
_x000D_

Creating new database from a backup of another Database on the same server?

I think that is easier than this.

  • First, create a blank target database.
  • Then, in "SQL Server Management Studio" restore wizard, look for the option to overwrite target database. It is in the 'Options' tab and is called 'Overwrite the existing database (WITH REPLACE)'. Check it.
  • Remember to select target files in 'Files' page.

You can change 'tabs' at left side of the wizard (General, Files, Options)

XML to CSV Using XSLT

Here is a version with configurable parameters that you can set programmatically:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="text" encoding="utf-8" />

  <xsl:param name="delim" select="','" />
  <xsl:param name="quote" select="'&quot;'" />
  <xsl:param name="break" select="'&#xA;'" />

  <xsl:template match="/">
    <xsl:apply-templates select="projects/project" />
  </xsl:template>

  <xsl:template match="project">
    <xsl:apply-templates />
    <xsl:if test="following-sibling::*">
      <xsl:value-of select="$break" />
    </xsl:if>
  </xsl:template>

  <xsl:template match="*">
    <!-- remove normalize-space() if you want keep white-space at it is --> 
    <xsl:value-of select="concat($quote, normalize-space(), $quote)" />
    <xsl:if test="following-sibling::*">
      <xsl:value-of select="$delim" />
    </xsl:if>
  </xsl:template>

  <xsl:template match="text()" />
</xsl:stylesheet>

Convert UTC Epoch to local date

Addition to the above answer by @djechlin

d = '1394104654000';
new Date(parseInt(d));

converts EPOCH time to human readable date. Just don't forget that type of EPOCH time must be an Integer.

Deserialize a json string to an object in python

If you are embracing the type hints in Python 3.6, you can do it like this:

def from_json(data, cls):
    annotations: dict = cls.__annotations__ if hasattr(cls, '__annotations__') else None
    if issubclass(cls, List):
        list_type = cls.__args__[0]
        instance: list = list()
        for value in data:
            instance.append(from_json(value, list_type))
        return instance
    elif issubclass(cls, Dict):
            key_type = cls.__args__[0]
            val_type = cls.__args__[1]
            instance: dict = dict()
            for key, value in data.items():
                instance.update(from_json(key, key_type), from_json(value, val_type))
            return instance
    else:
        instance : cls = cls()
        for name, value in data.items():
            field_type = annotations.get(name)
            if inspect.isclass(field_type) and isinstance(value, (dict, tuple, list, set, frozenset)):
                setattr(instance, name, from_json(value, field_type))
            else:
                setattr(instance, name, value)
        return instance

Which then allows you do instantiate typed objects like this:

class Bar:
    value : int

class Foo:
    x : int
    bar : List[Bar]


obj : Foo = from_json(json.loads('{"x": 123, "bar":[{"value": 3}, {"value": 2}, {"value": 1}]}'), Foo)
print(obj.x)
print(obj.bar[2].value)

This syntax requires Python 3.6 though and does not cover all cases - for example, support for typing.Any... But at least it does not pollute the classes that need to be deserialized with extra init/tojson methods.

vba error handling in loop

As a general way to handle error in a loop like your sample code, I would rather use:

on error resume next
for each...
    'do something that might raise an error, then
    if err.number <> 0 then
         ...
    end if
 next ....

Interpreting "condition has length > 1" warning from `if` function

The way I cam across this question was when I tried doing something similar where I was defining a function and it was being called with the array like others pointed out

You could do something like this however for this scenarios its less elegant compared to Sven's method.

sapply(a, function(x) afunc(x))

afunc<-function(a){
  if (a>0){
    a/sum(a)
  }
  else 1
}

jQuery - Create hidden form element on the fly

The same as David's, but without attr()

$('<input>', {
    type: 'hidden',
    id: 'foo',
    name: 'foo',
    value: 'bar'
}).appendTo('form');

Change WPF window background image in C# code

The problem is the way you are using it in code. Just try the below code

public partial class MainView : Window
{
    public MainView()
    {
        InitializeComponent();

        ImageBrush myBrush = new ImageBrush();
        myBrush.ImageSource =
            new BitmapImage(new Uri("pack://application:,,,/icon.jpg", UriKind.Absolute));
        this.Background = myBrush;
    }
}

You can find more details regarding this in
http://msdn.microsoft.com/en-us/library/aa970069.aspx

Laravel Migration Error: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes

If you want to change in AppServiceProvider then you need to define the length of email field in migration. just replace the first line of code to the second line.

create_users_table

$table->string('email')->unique();
$table->string('email', 50)->unique();

create_password_resets_table

$table->string('email')->index();
$table->string('email', 50)->index();

After successfully changes you can run the migration.
Note: first you have to delete (if you have) users table, password_resets table from the database and delete users and password_resets entries from migration table.

Regular expression to match a line that doesn't contain a word

^((?!hede).)*$ is an elegant solution, except since it consumes characters you won't be able to combine it with other criteria. For instance, say you wanted to check for the non-presence of "hede" and the presence of "haha." This solution would work because it won't consume characters:

^(?!.*\bhede\b)(?=.*\bhaha\b) 

Resize iframe height according to content height in it

Try this, you can change for even when you want. this example use jQuery.

$('#iframe').live('mousemove', function (event) {   
    var theFrame = $(this, parent.document.body);
    this.height($(document.body).height() - 350);           
});

Reordering arrays

Change 2 to 1 as the first parameter in the splice call when removing the element:

var tmp = playlist.splice(1, 1);
playlist.splice(2, 0, tmp[0]);

Is it good practice to make the constructor throw an exception?

It is bad practice to throw Exception, as that requires anyone who calls your constructor to catch Exception which is a bad practice.

It is a good idea to have a constructor (or any method) throw an exception, generally speaking IllegalArgumentException, which is unchecked, and thus the compiler doesn't force you to catch it.

You should throw checked exceptions (things that extend from Exception, but not RuntimeException) if you want the caller to catch it.

openssl s_client -cert: Proving a client certificate was sent to the server

I know this is an old question but it does not yet appear to have an answer. I've duplicated this situation, but I'm writing the server app, so I've been able to establish what happens on the server side as well. The client sends the certificate when the server asks for it and if it has a reference to a real certificate in the s_client command line. My server application is set up to ask for a client certificate and to fail if one is not presented. Here is the command line I issue:

Yourhostname here -vvvvvvvvvv s_client -connect <hostname>:443 -cert client.pem -key cckey.pem -CAfile rootcert.pem -cipher ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH -tls1 -state

When I leave out the "-cert client.pem" part of the command the handshake fails on the server side and the s_client command fails with an error reported. I still get the report "No client certificate CA names sent" but I think that has been answered here above.

The short answer then is that the server determines whether a certificate will be sent by the client under normal operating conditions (s_client is not normal) and the failure is due to the server not recognizing the CA in the certificate presented. I'm not familiar with many situations in which two-way authentication is done although it is required for my project.

You are clearly sending a certificate. The server is clearly rejecting it.

The missing information here is the exact manner in which the certs were created and the way in which the provider loaded the cert, but that is probably all wrapped up by now.

Firefox and SSL: sec_error_unknown_issuer

June 2014:

This is the configuration I used and it working fine after banging my head on the wall for some days. I use Express 3.4 (I think is the same for Express 4.0)

var privateKey  = fs.readFileSync('helpers/sslcert/key.pem', 'utf8');
var certificate = fs.readFileSync('helpers/sslcert/csr.pem', 'utf8');

files = ["COMODORSADomainValidationSecureServerCA.crt",
         "COMODORSAAddTrustCA.crt",
         "AddTrustExternalCARoot.crt"
        ];

ca = (function() {
  var _i, _len, _results;

  _results = [];
  for (_i = 0, _len = files.length; _i < _len; _i++) {
    file = files[_i];
    _results.push(fs.readFileSync("helpers/sslcert/" + file));
  }
  return _results;
})();

var credentials = {ca:ca, key: privateKey, cert: certificate};

// process.env.PORT : Heroku Config environment
var port = process.env.PORT || 4000;

var app = express();
var server = http.createServer(app).listen(port, function() {
        console.log('Express HTTP server listening on port ' + server.address().port);
});
https.createServer(credentials, app).listen(3000, function() {
        console.log('Express HTTPS server listening on port ' + server.address().port);
});

// redirect all http requests to https
app.use(function(req, res, next) {
  if(!req.secure) {
    return res.redirect(['https://mydomain.com', req.url].join(''));
  }
  next();
});

Then I redirected the 80 and 443 ports:

sudo iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-ports 4000
sudo iptables -t nat -A PREROUTING -p tcp --dport 443 -j REDIRECT --to-ports 3000

As you can see after checking my certifications I have 4 [0,1,2,3]:

openssl s_client -connect mydomain.com:443 -showcerts | grep "^ "

ubuntu@ip-172-31-5-134:~$ openssl s_client -connect mydomain.com:443 -showcerts | grep "^ "
depth=3 C = SE, O = AddTrust AB, OU = AddTrust External TTP Network, CN = AddTrust External CA Root
verify error:num=19:self signed certificate in certificate chain
verify return:0
 0 s:/OU=Domain Control Validated/OU=PositiveSSL/CN=mydomain.com
   i:/C=GB/ST=Greater Manchester/L=Salford/O=COMODO CA Limited/CN=COMODO RSA Domain Validation Secure Server CA
 1 s:/C=GB/ST=Greater Manchester/L=Salford/O=COMODO CA Limited/CN=COMODO RSA Domain Validation Secure Server CA
   i:/C=GB/ST=Greater Manchester/L=Salford/O=COMODO CA Limited/CN=COMODO RSA Certification Authority
 2 s:/C=GB/ST=Greater Manchester/L=Salford/O=COMODO CA Limited/CN=COMODO RSA Certification Authority
   i:/C=SE/O=AddTrust AB/OU=AddTrust External TTP Network/CN=AddTrust External CA Root
 3 s:/C=SE/O=AddTrust AB/OU=AddTrust External TTP Network/CN=AddTrust External CA Root
   i:/C=SE/O=AddTrust AB/OU=AddTrust External TTP Network/CN=AddTrust External CA Root
    Protocol  : TLSv1.1
    Cipher    : AES256-SHA
    Session-ID: 8FDEAEE92ED20742.....3E7D80F93226142DD
    Session-ID-ctx:
    Master-Key: C9E4AB966E41A85EEB7....4D73C67088E1503C52A9353C8584E94
    Key-Arg   : None
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    TLS session ticket lifetime hint: 300 (seconds)
    TLS session ticket:
    0000 - 7c c8 36 80 95 4d 4c 47-d8 e3 ca 2e 70 a5 8f ac   |.6..MLG....p...
    0010 - 90 bd 4a 26 ef f7 d6 bc-4a b3 dd 8f f6 13 53 e9   ..J&..........S.
    0020 - f7 49 c6 48 44 26 8d ab-a8 72 29 c8 15 73 f5 79   .I.HD&.......s.y
    0030 - ca 79 6a ed f6 b1 7f 8a-d2 68 0a 52 03 c5 84 32   .yj........R...2
    0040 - be c5 c8 12 d8 f4 36 fa-28 4f 0e 00 eb d1 04 ce   ........(.......
    0050 - a7 2b d2 73 df a1 8b 83-23 a6 f7 ef 6e 9e c4 4c   .+.s...........L
    0060 - 50 22 60 e8 93 cc d8 ee-42 22 56 a7 10 7b db 1e   P"`.....B.V..{..
    0070 - 0a ad 4a 91 a4 68 7a b0-9e 34 01 ec b8 7b b2 2f   ..J......4...{./
    0080 - e8 33 f5 a9 48 11 36 f8-69 a6 7a a6 22 52 b1 da   .3..H...i....R..
    0090 - 51 18 ed c4 d9 3d c4 cc-5b d7 ff 92 4e 91 02 9e   .....=......N...
    Start Time: 140...549
    Timeout   : 300 (sec)
    Verify return code: 19 (self signed certificate in certificate chain)

Good luck! PD: if u want more answers please check: http://www.benjiegillam.com/2012/06/node-dot-js-ssl-certificate-chain/

How do you calculate the variance, median, and standard deviation in C++ or Java?

To calculate the mean, loop through the list/array of numbers, keeping track of the partial sums and the length. Then return the sum/length.

double sum = 0.0;
int length = 0;

for( double number : numbers ) {
    sum += number;
    length++;
}

return sum/length;

Variance is calculated similarly. Standard deviation is simply the square root of the variance:

double stddev = Math.sqrt( variance );

How to set caret(cursor) position in contenteditable element (div)?

  const el = document.getElementById("editable");
  el.focus()
  let char = 1, sel; // character at which to place caret

  if (document.selection) {
    sel = document.selection.createRange();
    sel.moveStart('character', char);
    sel.select();
  }
  else {
    sel = window.getSelection();
    sel.collapse(el.lastChild, char);
  }

Is it possible to "decompile" a Windows .exe? Or at least view the Assembly?

If you want to run the program to see what it does without infecting your computer, use with a virtual machine like VMWare or Microsoft VPC, or a program that can sandbox the program like SandboxIE

PHP shorthand for isset()?

PHP 7.4+; with the null coalescing assignment operator

$var ??= '';

PHP 7.0+; with the null coalescing operator

$var = $var ?? '';

PHP 5.3+; with the ternary operator shorthand

isset($var) ?: $var = '';

Or for all/older versions with isset:

$var = isset($var) ? $var : '';

or

!isset($var) && $var = '';

React router nav bar example

Note The accepted is perfectly fine - but wanted to add a version4 example because they are different enough.

Nav.js

  import React from 'react';
  import { Link } from 'react-router';

  export default class Nav extends React.Component {
    render() {    
      return (
        <nav className="Nav">
          <div className="Nav__container">
            <Link to="/" className="Nav__brand">
              <img src="logo.svg" className="Nav__logo" />
            </Link>

            <div className="Nav__right">
              <ul className="Nav__item-wrapper">
                <li className="Nav__item">
                  <Link className="Nav__link" to="/path1">Link 1</Link>
                </li>
                <li className="Nav__item">
                  <Link className="Nav__link" to="/path2">Link 2</Link>
                </li>
                <li className="Nav__item">
                  <Link className="Nav__link" to="/path3">Link 3</Link>
                </li>
              </ul>
            </div>
          </div>
        </nav>
      );
    }
  }

App.js

  import React from 'react';
  import { Link, Switch, Route } from 'react-router';
  import Nav from './nav';
  import Page1 from './page1';
  import Page2 from './page2';
  import Page3 from './page3';

  export default class App extends React.Component {
    render() {    
      return (
        <div className="App">
          <Router>
            <div>
              <Nav />
              <Switch>
                <Route exactly component={Landing} pattern="/" />
                <Route exactly component={Page1} pattern="/path1" />
                <Route exactly component={Page2} pattern="/path2" />
                <Route exactly component={Page3} pattern="/path3" />
                <Route component={Page404} />
              </Switch>
            </div>
          </Router>
        </div>
      );
    }
  }

Alternatively, if you want a more dynamic nav, you can look at the excellent v4 docs: https://reacttraining.com/react-router/web/example/sidebar

Edit

A few people have asked about a page without the Nav, such as a login page. I typically approach it with a wrapper Route component

  import React from 'react';
  import { Link, Switch, Route } from 'react-router';
  import Nav from './nav';
  import Page1 from './page1';
  import Page2 from './page2';
  import Page3 from './page3';

  const NavRoute = ({exact, path, component: Component}) => (
    <Route exact={exact} path={path} render={(props) => (
      <div>
        <Header/>
        <Component {...props}/>
      </div>
    )}/>
  )

  export default class App extends React.Component {
    render() {    
      return (
        <div className="App">
          <Router>
              <Switch>
                <NavRoute exactly component={Landing} pattern="/" />
                <Route exactly component={Login} pattern="/login" />
                <NavRoute exactly component={Page1} pattern="/path1" />
                <NavRoute exactly component={Page2} pattern="/path2" />
                <NavRoute component={Page404} />
              </Switch>
          </Router>
        </div>
      );
    }
  }

Regular Expression For Duplicate Words

I believe this regex handles more situations:

/(\b\S+\b)\s+\b\1\b/

A good selection of test strings can be found here: http://callumacrae.github.com/regex-tuesday/challenge1.html

How to get the employees with their managers

This is a classic self-join, try the following:

SELECT e.ename, e.empno, m.ename as manager, e.mgr
FROM
    emp e, emp m
WHERE e.mgr = m.empno

And if you want to include the president which has no manager then instead of an inner join use an outer join in Oracle syntax:

SELECT e.ename, e.empno, m.ename as manager, e.mgr
FROM
    emp e, emp m
WHERE e.mgr = m.empno(+)

Or in ANSI SQL syntax:

SELECT e.ename, e.empno, m.ename as manager, e.mgr
FROM
    emp e
    LEFT OUTER JOIN emp m
        ON e.mgr = m.empno

iterating through Enumeration of hastable keys throws NoSuchElementException error

You're calling e.nextElement() twice inside your loop when you're only guaranteed that you can call it once without an exception. Rewrite the loop like so:

while(e.hasMoreElements()){
  String param = e.nextElement();
  System.out.println(param);
}

How to print in C

In C, unlike say C++, you would need a format specifier that states the datatype of the variable you want to print-in this case %d as the data type is an integer . Try printf("%d",addNumbers(a,b));

Change bundle identifier in Xcode when submitting my first app in IOS

I know that its late but it might be helpful for people who need to change the Bundle Identifier of the app. In the finder go to the project folder:

the project file --> Right click on your project file '*.xcodeproj' 

enter image description here

--> choose 'Show Package Contents' 
--> Double click to open 'project.pbxproj' file 

enter image description here

--> find 'productName = NAME_YOU_WANT_TO_CHANGE' in the 
    '/* Begin PBXNativeTarget section */'

The ${PRODUCT_NAME:rfc1034identifier} variable will be replaced with the name you have entered and new Bundle Identifier will be updated to what you need it to be.

Difference between Visual Basic 6.0 and VBA

It's VBA. VBA means Visual Basic for Applications, and it is used for macros on Office documents. It doesn't have access to VB.NET features, so it's more like a modified version of VB6, with add-ons to be able to work on the document (like Worksheet in VBA for Excel).

How to loop and render elements in React.js without an array of objects to map?

Here is more functional example with some ES6 features:

'use strict';

const React = require('react');

function renderArticles(articles) {
    if (articles.length > 0) {      
        return articles.map((article, index) => (
            <Article key={index} article={article} />
        ));
    }
    else return [];
}

const Article = ({article}) => {
    return ( 
        <article key={article.id}>
            <a href={article.link}>{article.title}</a>
            <p>{article.description}</p>
        </article>
    );
};

const Articles = React.createClass({
    render() {
        const articles = renderArticles(this.props.articles);

        return (
            <section>
                { articles }
            </section>
        );
    }
});

module.exports = Articles;

How can I override the OnBeforeUnload dialog and replace it with my own?

You can't modify the default dialogue for onbeforeunload, so your best bet may be to work with it.

window.onbeforeunload = function() {
    return 'You have unsaved changes!';
}

Here's a reference to this from Microsoft:

When a string is assigned to the returnValue property of window.event, a dialog box appears that gives users the option to stay on the current page and retain the string that was assigned to it. The default statement that appears in the dialog box, "Are you sure you want to navigate away from this page? ... Press OK to continue, or Cancel to stay on the current page.", cannot be removed or altered.

The problem seems to be:

  1. When onbeforeunload is called, it will take the return value of the handler as window.event.returnValue.
  2. It will then parse the return value as a string (unless it is null).
  3. Since false is parsed as a string, the dialogue box will fire, which will then pass an appropriate true/false.

The result is, there doesn't seem to be a way of assigning false to onbeforeunload to prevent it from the default dialogue.

Additional notes on jQuery:

  • Setting the event in jQuery may be problematic, as that allows other onbeforeunload events to occur as well. If you wish only for your unload event to occur I'd stick to plain ol' JavaScript for it.
  • jQuery doesn't have a shortcut for onbeforeunload so you'd have to use the generic bind syntax.

    $(window).bind('beforeunload', function() {} );
    

Edit 09/04/2018: custom messages in onbeforeunload dialogs are deprecated since chrome-51 (cf: release note)

export html table to csv

A Modern Solution

Most of the proposed solutions here will break with nested tables or other elements inside your td elements. I frequently use other elements inside my tables, but only want to export the topmost table. I took some of the code found here from Calumah and added in some modern vanilla ES6 JS.

Using textContent is a better solution than innerText as innerText will return any HTML inside your td elements. However, even textContent will return the text from nested elements. An even better solution is to use custom data attributes on your td and pull the values for you CSV from there.

Happy coding!

function downloadAsCSV(tableEle, separator = ','){
    let csvRows = []
    //only get direct children of the table in question (thead, tbody)
    Array.from(tableEle.children).forEach(function(node){
        //using scope to only get direct tr of node
        node.querySelectorAll(':scope > tr').forEach(function(tr){
            let csvLine = []
            //again scope to only get direct children
            tr.querySelectorAll(':scope > td').forEach(function(td){
                //clone as to not remove anything from original
                let copytd = td.cloneNode(true)
                let data
                if(copytd.dataset.val) data = copytd.dataset.val.replace(/(\r\n|\n|\r)/gm, '')
                else {
                    Array.from(copytd.children).forEach(function(remove){
                        //remove nested elements before getting text
                        remove.parentNode.removeChild(remove)   
                    })
                    data = copytd.textContent.replace(/(\r\n|\n|\r)/gm, '')
                }
                data = data.replace(/(\s\s)/gm, ' ').replace(/"/g, '""')
                csvLine.push('"'+data+'"')
            })
            csvRows.push(csvLine.join(separator))
        })
    })
    var a = document.createElement("a")
    a.style = "display: none; visibility: hidden" //safari needs visibility hidden
    a.href = 'data:text/csv;charset=utf-8,' + encodeURIComponent(csvRows.join('\n'))
    a.download = 'testfile.csv'
    document.body.appendChild(a)
    a.click()
    a.remove()
}

Edit: cloneNode() updated to cloneNode(true) to get insides

Creating SVG elements dynamically with javascript inside HTML

To facilitate svg editing you can use an intermediate function:

function getNode(n, v) {
  n = document.createElementNS("http://www.w3.org/2000/svg", n);
  for (var p in v)
    n.setAttributeNS(null, p, v[p]);
  return n
}

Now you can write:

svg.appendChild( getNode('rect', { width:200, height:20, fill:'#ff0000' }) );

Example (with an improved getNode function allowing camelcase for property with dash, eg strokeWidth > stroke-width):

_x000D_
_x000D_
function getNode(n, v) {_x000D_
  n = document.createElementNS("http://www.w3.org/2000/svg", n);_x000D_
  for (var p in v)_x000D_
    n.setAttributeNS(null, p.replace(/[A-Z]/g, function(m, p, o, s) { return "-" + m.toLowerCase(); }), v[p]);_x000D_
  return n_x000D_
}_x000D_
_x000D_
var svg = getNode("svg");_x000D_
document.body.appendChild(svg);_x000D_
_x000D_
var r = getNode('rect', { x: 10, y: 10, width: 100, height: 20, fill:'#ff00ff' });_x000D_
svg.appendChild(r);_x000D_
_x000D_
var r = getNode('rect', { x: 20, y: 40, width: 100, height: 40, rx: 8, ry: 8, fill: 'pink', stroke:'purple', strokeWidth:7 });_x000D_
svg.appendChild(r);
_x000D_
_x000D_
_x000D_

How to remove gem from Ruby on Rails application?

If you're using Rails 3+, remove the gem from the Gemfile and run bundle install.

If you're using Rails 2, hopefully you've put the declaration in config/environment.rb. If so, removing it from there and running rake gems:install should do the trick.

How to print a single backslash?

A hacky way of printing a backslash that doesn't involve escaping is to pass its character code to chr:

>>> print(chr(92))
\

Error: Tablespace for table xxx exists. Please DISCARD the tablespace before IMPORT

Xampp and Mamp Users

Had the same error while importing a database (after emptying it) trough MySQL. I found that i had a tablename.ibd file left while all others were deleted. I deleted it manually from mysql/data/database_name and the error was gone.

Android: how to parse URL String with spaces to URI object?

I wrote this function:

public static String encode(@NonNull String uriString) {
    if (TextUtils.isEmpty(uriString)) {
        Assert.fail("Uri string cannot be empty!");
        return uriString;
    }
    // getQueryParameterNames is not exist then cannot iterate on queries
    if (Build.VERSION.SDK_INT < 11) {
        return uriString;
    }

    // Check if uri has valid characters
    // See https://tools.ietf.org/html/rfc3986
    Pattern allowedUrlCharacters = Pattern.compile("([A-Za-z0-9_.~:/?\\#\\[\\]@!$&'()*+,;" +
            "=-]|%[0-9a-fA-F]{2})+");
    Matcher matcher = allowedUrlCharacters.matcher(uriString);
    String validUri = null;
    if (matcher.find()) {
        validUri = matcher.group();
    }
    if (TextUtils.isEmpty(validUri) || uriString.length() == validUri.length()) {
        return uriString;
    }

    // The uriString is not encoded. Then recreate the uri and encode it this time
    Uri uri = Uri.parse(uriString);
    Uri.Builder uriBuilder = new Uri.Builder()
            .scheme(uri.getScheme())
            .authority(uri.getAuthority());
    for (String path : uri.getPathSegments()) {
        uriBuilder.appendPath(path);
    }
    for (String key : uri.getQueryParameterNames()) {
        uriBuilder.appendQueryParameter(key, uri.getQueryParameter(key));
    }
    String correctUrl = uriBuilder.build().toString();
    return correctUrl;
}

python socket.error: [Errno 98] Address already in use

There is obviously another process listening on the port. You might find out that process by using the following command:

$ lsof -i :8000

or change your tornado app's port. tornado's error info not Explicitly on this.

jQuery - getting custom attribute from selected option

Here is the entire script with an AJAX call to target a single list within a page with multiple lists. None of the other stuff above worked for me until I used the "id" attribute even though my attribute name is "ItemKey". By using the debugger

Chrome Debug

I was able to see that the selected option had attributes: with a map to the JQuery "id" and the value.

<html>
<head>
<script type="text/JavaScript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
</head>
<body>
<select id="List1"></select>
<select id="List2">
<option id="40000">List item #1</option>
<option id="27888">List item #2</option>
</select>

<div></div>
</body>
<script type="text/JavaScript">
//get a reference to the select element
$select = $('#List1');

//request the JSON data and parse into the select element
$.ajax({
url: 'list.json',
dataType:'JSON',
success:function(data){

//clear the current content of the select
$select.html('');

//iterate over the data and append a select option
$.each(data.List, function(key, val){
$select.append('<option id="' + val.ItemKey + '">' + val.ItemText + '</option>');
})
},

error:function(){

//if there is an error append a 'none available' option
$select.html('<option id="-1">none available</option>');
}
});

$( "#List1" ).change(function () {
var optionSelected = $('#List1 option:selected').attr('id');
$( "div" ).text( optionSelected );
});
</script>
</html>

Here is the JSON File to create...

{  
"List":[  
{  
"Sort":1,
"parentID":0,
"ItemKey":100,
"ItemText":"ListItem-#1"
},
{  
"Sort":2,
"parentID":0,
"ItemKey":200,
"ItemText":"ListItem-#2"
},
{  
"Sort":3,
"parentID":0,
"ItemKey":300,
"ItemText":"ListItem-#3"
},
{  
"Sort":4,
"parentID":0,
"ItemKey":400,
"ItemText":"ListItem-#4"
}
]
}

Hope this helps, thank you all above for getting me this far.

Exposing the current state name with ui router

this is how I do it

JAVASCRIPT:

var module = angular.module('yourModuleName', ['ui.router']);

module.run( ['$rootScope', '$state', '$stateParams',
                      function ($rootScope,   $state,   $stateParams) {
    $rootScope.$state = $state;
    $rootScope.$stateParams = $stateParams; 
}
]);

HTML:

<pre id="uiRouterInfo">
      $state = {{$state.current.name}}
      $stateParams = {{$stateParams}}
      $state full url = {{ $state.$current.url.source }}    
</pre>

EXAMPLE

http://plnkr.co/edit/LGMZnj?p=preview

anchor jumping by using javascript

You can get the coordinate of the target element and set the scroll position to it. But this is so complicated.

Here is a lazier way to do that:

function jump(h){
    var url = location.href;               //Save down the URL without hash.
    location.href = "#"+h;                 //Go to the target element.
    history.replaceState(null,null,url);   //Don't like hashes. Changing it back.
}

This uses replaceState to manipulate the url. If you also want support for IE, then you will have to do it the complicated way:

function jump(h){
    var top = document.getElementById(h).offsetTop; //Getting Y of target element
    window.scrollTo(0, top);                        //Go there directly or some transition
}?

Demo: http://jsfiddle.net/DerekL/rEpPA/
Another one w/ transition: http://jsfiddle.net/DerekL/x3edvp4t/

You can also use .scrollIntoView:

document.getElementById(h).scrollIntoView();   //Even IE6 supports this

(Well I lied. It's not complicated at all.)

Clear dropdown using jQuery Select2

This is how I do:

$('#my_input').select2('destroy').val('').select2();

Is there a method that tells my program to quit?

The actual way to end a program, is to call

raise SystemExit

It's what sys.exit does, anyway.

A plain SystemExit, or with None as a single argument, sets the process' exit code to zero. Any non-integer exception value (raise SystemExit("some message")) prints the exception value to sys.stderr and sets the exit code to 1. An integer value sets the process' exit code to the value:

$ python -c "raise SystemExit(4)"; echo $?
4

How to ssh from within a bash script?

There's yet another way to do it using Shared Connections, ie: somebody initiates the connection, using a password, and every subsequent connection will multiplex over the same channel, negating the need for re-authentication. ( And its faster too )

# ~/.ssh/config 
ControlMaster auto
ControlPath ~/.ssh/pool/%r@%h

then you just have to log in, and as long as you are logged in, the bash script will be able to open ssh connections.

You can then stop your script from working when somebody has not already opened the channel by:

ssh ... -o KbdInteractiveAuthentication=no ....

DataTable, How to conditionally delete rows

Here's a one-liner using LINQ and avoiding any run-time evaluation of select strings:

someDataTable.Rows.Cast<DataRow>().Where(
    r => r.ItemArray[0] == someValue).ToList().ForEach(r => r.Delete());

Unresolved external symbol in object files

I had an error where my project was compiled as x64 project. and I've used a Library that was compiled as x86.

I've recompiled the library as x64 and it solved it.

PHP array() to javascript array()

You should need to convert your PHP array to javascript array using PHP syntax json_encode. json_encode convert PHP array to JSON string

Single Dimension PHP array to javascript array

<?php
var $itemsarray= array("Apple", "Bear", "Cat", "Dog");
?>
<script>
var items= <?php echo json_encode($itemsarray); ?>;
console.log(items[2]); // Output: Bear
// OR
alert(items[0]); // Output: Apple
</script>

Multi Dimension PHP array to javascript array

<?php
var $itemsarray= array( 
               array('name'='Apple', 'price'=>'12345'),
               array('name'='Bear', 'price'=>'13344'),
               array('name'='Potato', 'price'=>'00440')
             );
?>


<script>
var items= <?php echo json_encode($itemsarray); ?>;
console.log(items[1][name]); // Output: Bear
// OR
alert(items[0][price]); // Output: Apple
</script>

For more detail, you can also check php array to javascript array

Sending an HTTP POST request on iOS

Sending an HTTP POST request on iOS (Objective c):

-(NSString *)postexample{

// SEND POST
NSString *url = [NSString stringWithFormat:@"URL"];
NSString *post = [NSString stringWithFormat:@"param=value"];
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:@"%d",[postData length]];


NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setHTTPMethod:@"POST"];
[request setURL:[NSURL URLWithString:url]];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:postData];

NSError *error = nil;
NSHTTPURLResponse *responseCode = nil;

//RESPONDE DATA 
NSData *oResponseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&responseCode error:&error];

if([responseCode statusCode] != 200){
    NSLog(@"Error getting %@, HTTP status code %li", url, (long)[responseCode statusCode]);
    return nil;
}

//SEE RESPONSE DATA
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Response" message:[[NSString alloc] initWithData:oResponseData encoding:NSUTF8StringEncoding] delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];
[alert show];

return [[NSString alloc] initWithData:oResponseData encoding:NSUTF8StringEncoding];
}