Programs & Examples On #Gquery

GwtQuery a.k.a. gQuery is a jQuery-like API written in GWT. It offers the possibility to use the jquery api in gwt projects.

Import data into Google Colaboratory

step 1- Mount your Google Drive to Collaboratory

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

step 2- Now you will see your Google Drive files in the left pane (file explorer). Right click on the file that you need to import and select çopy path. Then import as usual in pandas, using this copied path.

import pandas as pd
df=pd.read_csv('gdrive/My Drive/data.csv')

Done!

Unable to update the EntitySet - because it has a DefiningQuery and no <UpdateFunction> element exist

This can also happen if data model is out of date.

Hopefully this will save someone else frustration :)

ascending/descending in LINQ - can one change the order via parameter?

In addition to the beautiful solution given by @Jon Skeet, I also needed ThenBy and ThenByDescending, so I am adding it based on his solution:

    public static IOrderedEnumerable<TSource> ThenByWithDirection<TSource, TKey>(
         this IOrderedEnumerable<TSource> source, 
         Func<TSource, TKey> keySelector,  
         bool descending)
    {
        return descending ? 
               source.ThenByDescending(keySelector) :
               source.ThenBy(keySelector);
    }

How to make a <div> appear in front of regular text/tables

You may add a div with position:absolute within a table/div with position:relative. For example, if you want your overlay div to be shown at the bottom right of the main text div (width and height can be removed):

<div style="position:relative;width:300px;height:300px;background-color:#eef">
    <div style="position:absolute;bottom:0;right:0;width:100px;height:100px;background-color:#fee">
        I'm over you!
    </div>
    Your main text
</div>

See it here: http://jsfiddle.net/bptvt5kb/

Netbeans how to set command line arguments in Java

In NetBeans IDE 8.0 you can use a community contributed plugin https://github.com/tusharvjoshi/nbrunwithargs which will allow you to pass arguments while Run Project or Run Single File command.

For passing arguments to Run Project command either you have to set the arguments in the Project properties Run panel, or use the new command available after installing the plugin which says Run with Arguments

For passing command line arguments to a Java file having main method, just right click on the method and choose Run with Arguments command, of this plugin

UPDATE (24 mar 2014) This plugin is now available in NetBeans Plugin Portal that means it can be installed from Plugins dialog box from the available plugins shown from community contributed plugins, in NetBeans IDE 8.0

Run with Arguments plugin as shown in Plugin dialog box

Insecure content in iframe on secure page

Based on generality of this question, I think, that you'll need to setup your own HTTPS proxy on some server online. Do the following steps:

  • Prepare your proxy server - install IIS, Apache
  • Get valid SSL certificate to avoid security errors (free from startssl.com for example)
  • Write a wrapper, which will download insecure content (how to below)
  • From your site/app get https://yourproxy.com/?page=http://insecurepage.com

If you simply download remote site content via file_get_contents or similiar, you can still have insecure links to content. You'll have to find them with regex and also replace. Images are hard to solve, but Ï found workaround here: http://foundationphp.com/tutorials/image_proxy.php


Note: While this solution may have worked in some browsers when it was written in 2014, it no longer works. Navigating or redirecting to an HTTP URL in an iframe embedded in an HTTPS page is not permitted by modern browsers, even if the frame started out with an HTTPS URL.

The best solution I created is to simply use google as the ssl proxy...

https://www.google.com/search?q=%http://yourhttpsite.com&btnI=Im+Feeling+Lucky

Tested and works in firefox.

Other Methods:

  • Use a Third party such as embed.ly (but it it really only good for well known http APIs).

  • Create your own redirect script on an https page you control (a simple javascript redirect on a relative linked page should do the trick. Something like: (you can use any langauge/method)

    https://example.com That has a iframe linking to...

    https://example.com/utilities/redirect.html Which has a simple js redirect script like...

    document.location.href ="http://thenonsslsite.com";

  • Alternatively, you could add an RSS feed or write some reader/parser to read the http site and display it within your https site.

  • You could/should also recommend to the http site owner that they create an ssl connection. If for no other reason than it increases seo.

Unless you can get the http site owner to create an ssl certificate, the most secure and permanent solution would be to create an RSS feed grabing the content you need (presumably you are not actually 'doing' anything on the http site -that is to say not logging in to any system).

The real issue is that having http elements inside a https site represents a security issue. There are no completely kosher ways around this security risk so the above are just current work arounds.

Note, that you can disable this security measure in most browsers (yourself, not for others). Also note that these 'hacks' may become obsolete over time.

How to compare datetime with only date in SQL Server

According to your query Select * from [User] U where U.DateCreated = '2014-02-07'

SQL Server is comparing exact date and time i.e (comparing 2014-02-07 12:30:47.220 with 2014-02-07 00:00:00.000 for equality). that's why result of comparison is false

Therefore, While comparing dates you need to consider time also. You can use
Select * from [User] U where U.DateCreated BETWEEN '2014-02-07' AND '2014-02-08'.

Delete with "Join" in Oracle sql Query

Use a subquery in the where clause. For a delete query requirig a join, this example will delete rows that are unmatched in the joined table "docx_document" and that have a create date > 120 days in the "docs_documents" table.

delete from docs_documents d
where d.id in (
    select a.id from docs_documents a
    left join docx_document b on b.id = a.document_id
    where b.id is null
        and floor(sysdate - a.create_date) > 120
 );

What is 'PermSize' in Java?

The permament pool contains everything that is not your application data, but rather things required for the VM: typically it contains interned strings, the byte code of defined classes, but also other "not yours" pieces of data.

How can I decrease the size of Ratingbar?

Working Example

             <RatingBar
                style="@style/RatingBar"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:numStars="5"
                android:rating="3.5"
                android:stepSize="0.5" />

and add this in your styles xml file

<style name="RatingBar"   
parent="android:style/Widget.Material.RatingBar.Small">
<item name="colorControlNormal">@color/primary_light</item>
<item name="colorControlActivated">@color/primary_dark</item>
</style>

This way you dont need to customise ratingBar.

How to sort an ArrayList in Java

Implement Comparable interface to Fruit.

public class Fruit implements Comparable<Fruit> {

It implements the method

@Override
    public int compareTo(Fruit fruit) {
        //write code here for compare name
    }

Then do call sort method

Collections.sort(fruitList);

Fatal error: Call to a member function query() on null

put this line in parent construct : $this->load->database();

function  __construct() {
    parent::__construct();
    $this->load->library('lib_name');
    $model=array('model_name');
    $this->load->model($model);
    $this->load->database();
}

this way.. it should work..

Firing a Keyboard Event in Safari, using JavaScript

The Mozilla Developer Network provides the following explanation:

  1. Create an event using event = document.createEvent("KeyboardEvent")
  2. Init the keyevent

using:

event.initKeyEvent (type, bubbles, cancelable, viewArg, 
       ctrlKeyArg, altKeyArg, shiftKeyArg, metaKeyArg, 
           keyCodeArg, charCodeArg)
  1. Dispatch the event using yourElement.dispatchEvent(event)

I don't see the last one in your code, maybe that's what you're missing. I hope this works in IE as well...

MySQL DROP all tables, ignoring foreign keys

From this answer,

execute:

  use `dbName`; --your db name here
  SET FOREIGN_KEY_CHECKS = 0; 
  SET @tables = NULL;
  SET GROUP_CONCAT_MAX_LEN=32768;

  SELECT GROUP_CONCAT('`', table_schema, '`.`', table_name, '`') INTO @tables
  FROM   information_schema.tables 
  WHERE  table_schema = (SELECT DATABASE());
  SELECT IFNULL(@tables, '') INTO @tables;

  SET        @tables = CONCAT('DROP TABLE IF EXISTS ', @tables);
  PREPARE    stmt FROM @tables;
  EXECUTE    stmt;
  DEALLOCATE PREPARE stmt;
  SET        FOREIGN_KEY_CHECKS = 1;

This drops tables from the database currently in use. You can set current database using use.


Or otherwise, Dion's accepted answer is simpler, except you need to execute it twice, first to get the query, and second to execute the query. I provided some silly back-ticks to escape special characters in db and table names.

  SELECT CONCAT('DROP TABLE IF EXISTS `', table_schema, '`.`', table_name, '`;')
  FROM   information_schema.tables
  WHERE  table_schema = 'dbName'; --your db name here

C++ - Hold the console window open?

If your problem is retaining the Console Window within Visual Studio without modifying your application (c-code) and are running it with Ctrl+F5 (when running Ctrl+F5) but the window is still closing the principal hint is to set the /SUBSYSTEM:CONSOLE linker option in your Visual Studio project.

as explained by DJMooreTX in http://social.msdn.microsoft.com/Forums/en-US/vcprerelease/thread/21073093-516c-49d2-81c7-d960f6dc2ac6

1) Open up your project, and go to the Solution Explorer. If you're following along with me in K&R, your "Solution" will be 'hello' with 1 project under it, also 'hello' in bold.

  1. Right click on the 'hello" (or whatever your project name is.)

  2. Choose "Properties" from the context menu.

  3. Choose Configuration Properties>Linker>System.

  4. For the "Subsystem" property in the right-hand pane, click the drop-down box in the right hand column.

  5. Choose "Console (/SUBSYSTEM:CONSOLE)"

  6. Click Apply, wait for it to finish doing whatever it does, then click OK. (If "Apply" is grayed out, choose some other subsystem option, click Apply, then go back and apply the console option. My experience is that OK by itself won't work.)

Now do Boris' CTRL-F5, wait for your program to compile and link, find the console window under all the other junk on your desktop, and read your program's output, followed by the beloved "Press any key to continue...." prompt.

Again, CTRL-F5 and the subsystem hints work together; they are not separate options.

What does the construct x = x || y mean?

Double pipe stands for logical "OR". This is not really the case when the "parameter not set", since strictly in the javascript if you have code like this:

function foo(par) {
}

Then calls

foo()
foo("")
foo(null)
foo(undefined)
foo(0)

are not equivalent.

Double pipe (||) will cast the first argument to boolean and if resulting boolean is true - do the assignment otherwise it will assign the right part.

This matters if you check for unset parameter.

Let's say, we have a function setSalary that has one optional parameter. If user does not supply the parameter then the default value of 10 should be used.

if you do the check like this:

function setSalary(dollars) {
    salary = dollars || 10
}

This will give unexpected result on call like

setSalary(0) 

It will still set the 10 following the flow described above.

How to reset Android Studio

We can no longer reset android studio to it's default state by the answers/methods given in this question from android studio 3.2.0 Here is the updated new method to do it (It consumes less time as it does not require any update/installation).

For Windows/Mac

  1. Open my computer

  2. Go to C:\Users\Username\.android\build-cache

  3. Delete the cache/files found inside the folder build-cache

  4. Note: do not delete the folder named as "3.2.0" and "3.2.1" which will be inside the build-cache

  5. Restart Android studio.

and that would completely reset your android studio settings from Android studio 3.2.0 and up.

jquery ajax get responsetext from http url

As Karim said, cross domain ajax doesn't work unless the server allows for it. In this case Google does not, BUT, there is a simple trick to get around this in many cases. Just have your local server pass the content retrieved through HTTP or HTTPS.

For example, if you were using PHP, you could:

Create the file web_root/ajax_responders/google.php with:

<?php
  echo file_get_contents('http://www.google.de');
?>

And then alter your code to connect to that instead of to Google's domain directly in the javascript:

var response = $.ajax({ type: "GET",   
                        url: "/ajax_responders/google.php",   
                        async: false
                      }).responseText;
alert(response);

HTML form with multiple "actions"

the best way (for me) to make it it's the next infrastructure:

<form method="POST">
<input type="submit" formaction="default_url_when_press_enter" style="visibility: hidden; display: none;">
<!-- all your inputs -->
<input><input><input>
<!-- all your inputs -->
<button formaction="action1">Action1</button>
<button formaction="action2">Action2</button>
<input type="submit" value="Default Action">
</form>

with this structure you will send with enter a direction and the infinite possibilities for the rest of buttons.

how to check if a datareader is null or empty

Try this simpler equivalent syntax:

ltlAdditional.Text = (myReader["Additional"] == DBNull.Value) ? "is null" : "contains data";

Add item to array in VBScript

There are a few ways, not including a custom COM or ActiveX object

  1. ReDim Preserve
  2. Dictionary object, which can have string keys and search for them
  3. ArrayList .Net Framework Class, which has many methods including: sort (forward, reverse, custom), insert, remove, binarysearch, equals, toArray, and toString

With the code below, I found Redim Preserve is fastest below 54000, Dictionary is fastest from 54000 to 690000, and Array List is fastest above 690000. I tend to use ArrayList for pushing because of the sorting and array conversion.

user326639 provided FastArray, which is pretty much the fastest.

Dictionaries are useful for searching for the value and returning the index (i.e. field names), or for grouping and aggregation (histograms, group and add, group and concatenate strings, group and push sub-arrays). When grouping on keys, set CompareMode for case in/sensitivity, and check the "exists" property before "add"-ing.

Redim wouldn't save much time for one array, but it's useful for a dictionary of arrays.

'pushtest.vbs
imax = 10000
value = "Testvalue"
s = imax & " of """ & value & """" 

t0 = timer 'ArrayList Method
Set o = CreateObject("System.Collections.ArrayList")
For i = 0 To imax
  o.Add value
Next
s = s & "[AList " & FormatNumber(timer - t0, 3, -1) & "]"
Set o = Nothing

t0 = timer 'ReDim Preserve Method
a = array()
For i = 0 To imax
  ReDim Preserve a(UBound(a) + 1)
  a(UBound(a)) = value
Next
s = s & "[ReDim " & FormatNumber(timer - t0, 3, -1) & "]"
Set a = Nothing

t0 = timer 'Dictionary Method
Set o = CreateObject("Scripting.Dictionary")
For i = 0 To imax
  o.Add i, value
Next
s = s & "[Dictionary " & FormatNumber(timer - t0, 3, -1) & "]"
Set o = Nothing

t0 = timer 'Standard array
Redim a(imax)
For i = 0 To imax
  a(i) = value
Next
s = s & "[Array " & FormatNumber(timer - t0, 3, -1) & "]" & vbCRLF
Set a = Nothing

t0 = timer 'Fast array
a = array()
For i = 0 To imax
 ub = UBound(a)
 If i>ub Then ReDim Preserve a(Int((ub+10)*1.1))
 a(i) = value
Next
ReDim Preserve a(i-1)
s = s & "[FastArr " & FormatNumber(timer - t0, 3, -1) & "]"
Set a = Nothing

MsgBox s

'  10000 of "Testvalue" [ArrayList 0.156][Redim 0.016][Dictionary 0.031][Array 0.016][FastArr 0.016]
'  54000 of "Testvalue" [ArrayList 0.734][Redim 0.672][Dictionary 0.203][Array 0.063][FastArr 0.109]
' 240000 of "Testvalue" [ArrayList 3.172][Redim 5.891][Dictionary 1.453][Array 0.203][FastArr 0.484]
' 690000 of "Testvalue" [ArrayList 9.078][Redim 44.785][Dictionary 8.750][Array 0.609][FastArr 1.406]
'1000000 of "Testvalue" [ArrayList 13.191][Redim 92.863][Dictionary 18.047][Array 0.859][FastArr 2.031]

How to display pie chart data values of each slice in chart.js

@Hung Tran's answer works perfect. As an improvement, I would suggest not showing values that are 0. Say you have 5 elements and 2 of them are 0 and rest of them have values, the solution above will show 0 and 0%. It is better to filter that out with a not equal to 0 check!

          var val = dataset.data[i];
          var percent = String(Math.round(val/total*100)) + "%";

          if(val != 0) {
            ctx.fillText(dataset.data[i], model.x + x, model.y + y);
            // Display percent in another line, line break doesn't work for fillText
            ctx.fillText(percent, model.x + x, model.y + y + 15);
          }

Updated code below:

var data = {
    datasets: [{
        data: [
            11,
            16,
            7,
            3,
            14
        ],
        backgroundColor: [
            "#FF6384",
            "#4BC0C0",
            "#FFCE56",
            "#E7E9ED",
            "#36A2EB"
        ],
        label: 'My dataset' // for legend
    }],
    labels: [
        "Red",
        "Green",
        "Yellow",
        "Grey",
        "Blue"
    ]
};

var pieOptions = {
  events: false,
  animation: {
    duration: 500,
    easing: "easeOutQuart",
    onComplete: function () {
      var ctx = this.chart.ctx;
      ctx.font = Chart.helpers.fontString(Chart.defaults.global.defaultFontFamily, 'normal', Chart.defaults.global.defaultFontFamily);
      ctx.textAlign = 'center';
      ctx.textBaseline = 'bottom';

      this.data.datasets.forEach(function (dataset) {

        for (var i = 0; i < dataset.data.length; i++) {
          var model = dataset._meta[Object.keys(dataset._meta)[0]].data[i]._model,
              total = dataset._meta[Object.keys(dataset._meta)[0]].total,
              mid_radius = model.innerRadius + (model.outerRadius - model.innerRadius)/2,
              start_angle = model.startAngle,
              end_angle = model.endAngle,
              mid_angle = start_angle + (end_angle - start_angle)/2;

          var x = mid_radius * Math.cos(mid_angle);
          var y = mid_radius * Math.sin(mid_angle);

          ctx.fillStyle = '#fff';
          if (i == 3){ // Darker text color for lighter background
            ctx.fillStyle = '#444';
          }

          var val = dataset.data[i];
          var percent = String(Math.round(val/total*100)) + "%";

          if(val != 0) {
            ctx.fillText(dataset.data[i], model.x + x, model.y + y);
            // Display percent in another line, line break doesn't work for fillText
            ctx.fillText(percent, model.x + x, model.y + y + 15);
          }
        }
      });               
    }
  }
};

var pieChartCanvas = $("#pieChart");
var pieChart = new Chart(pieChartCanvas, {
  type: 'pie', // or doughnut
  data: data,
  options: pieOptions
});

How to calculate the width of a text string of a specific font and font-size?

The way I am doing it my code is to make an extension of UIFont: (This is Swift 4.1)

extension UIFont {


    public func textWidth(s: String) -> CGFloat
    {
        return s.size(withAttributes: [NSAttributedString.Key.font: self]).width
    }

} // extension UIFont

Edit existing excel workbooks and sheets with xlrd and xlwt

Here's another way of doing the code above using the openpyxl module that's compatible with xlsx. From what I've seen so far, it also keeps formatting.

from openpyxl import load_workbook
wb = load_workbook('names.xlsx')
ws = wb['SheetName']
ws['A1'] = 'A1'
wb.save('names.xlsx')

Programmatically switching between tabs within Swift

1.Create a new class which supers UITabBarController. E.g:

class xxx: UITabBarController {
override func viewDidLoad() {
        super.viewDidLoad()
}

2.Add the following code to the function viewDidLoad():

self.selectedIndex = 1; //set the tab index you want to show here, start from 0

3.Go to storyboard, and set the Custom Class of your Tab Bar Controller to this new class. (MyVotes1 as the example in the pic)

enter image description here

How to set time to midnight for current day?

You can use the Date property of the DateTime object - eg

DateTime midnight = DateTime.Now.Date;

So your code example becomes

private DateTime _Begin = DateTime.Now.Date;
public DateTime Begin { get { return _Begin; } set { _Begin = value; } }

PS. going back to your original code setting the hours to 12 will give you time of noon for the current day, so instead you could have used 0...

var now = DateTime.Now;
new DateTime(now.Year, now.Month, now.Day, 0, 0, 0);

The type or namespace name 'Objects' does not exist in the namespace 'System.Data'

Same problem in VS 2013

I added in Web.config :

<add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />

It worked like a charm.

I found it on page: http://www.programmer.bz/Home/tabid/115/asp_net_sql/281/The-type-or-namespace-name-Objects-does-not-exist-in-the-namespace-SystemData.aspx

Using Axios GET with Authorization Header in React-Native App

For anyone else that comes across this post and might find it useful... There is actually nothing wrong with my code. I made the mistake of requesting client_credentials type access code instead of password access code (#facepalms). FYI I am using urlencoded post hence the use of querystring.. So for those that may be looking for some example code.. here is my full request

Big thanks to @swapnil for trying to help me debug this.

   const data = {
      grant_type: USER_GRANT_TYPE,
      client_id: CLIENT_ID,
      client_secret: CLIENT_SECRET,
      scope: SCOPE_INT,
      username: DEMO_EMAIL,
      password: DEMO_PASSWORD
    };



  axios.post(TOKEN_URL, Querystring.stringify(data))   
   .then(response => {
      console.log(response.data);
      USER_TOKEN = response.data.access_token;
      console.log('userresponse ' + response.data.access_token); 
    })   
   .catch((error) => {
      console.log('error ' + error);   
   });



const AuthStr = 'Bearer '.concat(USER_TOKEN); 
axios.get(URL, { headers: { Authorization: AuthStr } })
 .then(response => {
     // If request is good...
     console.log(response.data);
  })
 .catch((error) => {
     console.log('error ' + error);
  });

Most efficient way to increment a Map value in Java

@Vilmantas Baranauskas: Regarding this answer, I would comment if I had the rep points, but I don't. I wanted to note that the Counter class defined there is NOT thread-safe as it is not sufficient to just synchronize inc() without synchronizing value(). Other threads calling value() are not guaranteed to see the the value unless a happens-before relationship has been established with the update.

How to underline a UILabel in swift?

Swift 5 & 4.2 one liner:

label.attributedText = NSAttributedString(string: "Text", attributes:
    [.underlineStyle: NSUnderlineStyle.single.rawValue])

Swift 4 one liner:

label.attributedText = NSAttributedString(string: "Text", attributes:
    [.underlineStyle: NSUnderlineStyle.styleSingle.rawValue])

Swift 3 one liner:

label.attributedText = NSAttributedString(string: "Text", attributes:
      [NSUnderlineStyleAttributeName: NSUnderlineStyle.styleSingle.rawValue])

Zoom to fit: PDF Embedded in HTML

For me this worked(I wanted to zoom in since the container of my pdf was small):

    <embed src="filename.pdf#page=1&zoom=300" width="575" height="500">

Address already in use: JVM_Bind java

You can try deleting the Team Server credentials, most likely those will include some kind of port in the server column. Like https://wathever.visualstudio.com:443

Go to Windows/Preferences expand Team then Team Foundation Server go to Credentials and remove whichever is there.

Check OS version in Swift?

Update:
Now you should use new availability checking introduced with Swift 2:
e.g. To check for iOS 9.0 or later at compile time use this:

if #available(iOS 9.0, *) {
    // use UIStackView
} else {
    // show sad face emoji
}

or can be used with whole method or class

@available(iOS 9.0, *)
func useStackView() {
    // use UIStackView
}

For more info see this.

Run time checks:

if you don't want exact version but want to check iOS 9,10 or 11 using if:

let floatVersion = (UIDevice.current.systemVersion as NSString).floatValue

EDIT: Just found another way to achieve this:

let iOS8 = floor(NSFoundationVersionNumber) > floor(NSFoundationVersionNumber_iOS_7_1)
let iOS7 = floor(NSFoundationVersionNumber) <= floor(NSFoundationVersionNumber_iOS_7_1)

How to end C++ code

return 0; put that wherever you want within int main() and the program will immediately close.

Full screen background image in an activity

use this

android:background="@drawable/your_image"

in your activity very first linear or relative layout.

Convert Text to Date?

Besides other options, I confirm that using

c.Value = CDate(c.Value)

works (just tested with the description of your case, with Excel 2010). As for the reasons for you getting a type mismatch error, you may check (e.g.) this.

It might be a locale issue.

Why are only final variables accessible in anonymous class?

private void f(Button b, final int a[]) {

    b.addClickHandler(new ClickHandler() {

        @Override
        public void onClick(ClickEvent event) {
            a[0] = a[0] * 5;

        }
    });
}

Cannot create a connection to data source Error (rsErrorOpeningConnection) in SSRS

I had the exact same issue. The cause could be different but in my case, after trying several different things like changing the connection string on the Data Source setup, I found that this was the infamous 'double hop' issue (more info here).

To solve the problem, the following two options are available (as per one of the responses from the hyperlink):

  1.   Change the Report Server service to run under a domain user account, and register a SPN for the account.
    
  2.   Map Built-in accounts HTTP SPN to a Host SPN.
    

Using option 1, you need to select 'Windows' credentials instead of database credentials to overcome the double hop that happens while authentication.

windows credentials

What is perm space?

PermGen Space stands for memory allocation for Permanent generation All Java immutable objects come under this category, like String which is created with literals or with String.intern() methods and for loading the classes into memory. PermGen Space speeds up our String equality searching.

What's the difference between Sender, From and Return-Path?

A minor update to this: a sender should never set the Return-Path: header. There's no such thing as a Return-Path: header for a message in transit. That header is set by the MTA that makes final delivery, and is generally set to the value of the 5321.From unless the local system needs some kind of quirky routing.

It's a common misunderstanding because users rarely see an email without a Return-Path: header in their mailboxes. This is because they always see delivered messages, but an MTA should never see a Return-Path: header on a message in transit. See http://tools.ietf.org/html/rfc5321#section-4.4

How to present popover properly in iOS 8

In iOS9 UIPopoverController is depreciated. So can use the below code for Objective-C version above iOS9.x,

- (IBAction)onclickPopover:(id)sender {
UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]];
UIViewController *viewController = [sb instantiateViewControllerWithIdentifier:@"popover"];

viewController.modalPresentationStyle = UIModalPresentationPopover;
viewController.popoverPresentationController.sourceView = self.popOverBtn;
viewController.popoverPresentationController.sourceRect = self.popOverBtn.bounds;
viewController.popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirectionAny;
[self presentViewController:viewController animated:YES completion:nil]; }

Iframe transparent background

Why not just load the frame off screen or hidden and then display it once it has finished loading. You could show a loading icon in its place to begin with to give the user immediate feedback that it's loading.

calling javascript function on OnClientClick event of a Submit button

The above solutions must work. However you can try this one:

OnClientClick="return SomeMethod();return false;"

and remove return statement from the method.

How to build a RESTful API?

As simon marc said, the process is much the same as it is for you or I browsing a website. If you are comfortable with using the Zend framework, there are some easy to follow tutorials to that make life quite easy to set things up. The hardest part of building a restful api is the design of the it, and making it truly restful, think CRUD in database terms.

It could be that you really want an xmlrpc interface or something else similar. What do you want this interface to allow you to do?

--EDIT

Here is where I got started with restful api and Zend Framework. Zend Framework Example

In short don't use Zend rest server, it's obsolete.

How do I git rm a file without deleting it from disk?

git rm --cached file

should do what you want.

You can read more details at git help rm

How to obtain Certificate Signing Request

Since you installed a new OS you probably don't have any more of your private and public keys that you used to sign your app in to XCode before. You need to regenerate those keys on your machine by revoking your previous certificate and asking for a new one on the iOS development portal. As part of the process you will be asked to generate a Certificate Signing Request which is where you seem to have a problem.

You will find all you need there which consists of (from the official doc):

1.Open Keychain Access on your Mac (located in Applications/Utilities).

2.Open Preferences and click Certificates. Make sure both Online Certificate Status Protocol and Certificate Revocation List are set to Off.

3.Choose Keychain Access > Certificate Assistant > Request a Certificate From a Certificate Authority.

Note: If you have a private key selected when you do this, the CSR won’t be accepted. Make sure no private key is selected. Enter your user email address and common name. Use the same address and name as you used to register in the iOS Developer Program. No CA Email Address is required.

4.Select the options “Saved to disk” and “Let me specify key pair information” and click Continue.

5.Specify a filename and click Save. (make sure to replace .certSigningRequest with .csr)

For the Key Size choose 2048 bits and for Algorithm choose RSA. Click Continue and the Certificate Assistant creates a CSR and saves the file to your specified location.

What should I do if the current ASP.NET session is null?

If your Session instance is null and your in an 'ashx' file, just implement the 'IRequiresSessionState' interface.

This interface doesn't have any members so you just need to add the interface name after the class declaration (C#):

public class MyAshxClass : IHttpHandler, IRequiresSessionState

Finding first blank row, then writing to it

Very old thread but a simpler take :)

Sub firstBlank(c) 'as letter
    MsgBox (c & Split(Range(c & ":" & c).Find("", LookIn:=xlValues).address, "$")(2))
End Sub
Sub firstBlank(c) 'as number
    cLet = Split(Cells(1, c).address, "$")(1)
    MsgBox (cLet & Split(Range(cLet & ":" & cLet).Find("", LookIn:=xlValues).address, "$")(2))
End Sub

Java Program to test if a character is uppercase/lowercase/number/vowel

Some comments on your code

  • why would you want to have 2 for loops like for(i='A';i<='Z';i++), if you can check this with a simple if statement ... you loop over a whole range while you can simply check whether it is contained in that range
  • even when you found your answer (for example when input is A you will have your result the first time you enter the first loop) you still loop over all the rest
  • your System.out.println("Lowercase"); statement (and the uppercase statement) are placed in the wrong loop
  • If you are allowed to use it, I suggest to look at the Character class which has for example nice isUpperCase and isLowerCase methods

I leave the rest up to you since it is homework

Git Clone from GitHub over https with two-factor authentication

If your repo have 2FA enabled. Highly suggest to use the app provided by github.com Here is the link: https://desktop.github.com/

After you downloaded it and installed it. Follow the withard, the app will ask you to provide the one time password for login. Once you filled in the one time password, you could see your repo/projects now.

How do you truncate all tables in a database using TSQL?

If you want to keep data in a particular table (i.e. a static lookup table) while deleting/truncating data in other tables within the same db, then you need a loop with the exceptions in it. This is what I was looking for when I stumbled onto this question.

sp_MSForEachTable seems buggy to me (i.e. inconsistent behavior with IF statements) which is probably why its undocumented by MS.

declare @LastObjectID int = 0
declare @TableName nvarchar(100) = ''
set @LastObjectID = (select top 1 [object_id] from sys.tables where [object_id] > @LastObjectID order by [object_id])
while(@LastObjectID is not null)
begin
    set @TableName = (select top 1 [name] from sys.tables where [object_id] = @LastObjectID)

    if(@TableName not in ('Profiles', 'ClientDetails', 'Addresses', 'AgentDetails', 'ChainCodes', 'VendorDetails'))
    begin
        exec('truncate table [' + @TableName + ']')
    end 

    set @LastObjectID = (select top 1 [object_id] from sys.tables where [object_id] > @LastObjectID order by [object_id])
end

Merge, update, and pull Git branches without using checkouts

For many cases (such as merging), you can just use the remote branch without having to update the local tracking branch. Adding a message in the reflog sounds like overkill and will stop it being quicker. To make it easier to recover, add the following into your git config

[core]
    logallrefupdates=true

Then type

git reflog show mybranch

to see the recent history for your branch

Using subprocess to run Python script on Windows

Yes subprocess.Popen(cmd, ..., shell=True) works like a charm. On Windows the .py file extension is recognized, so Python is invoked to process it (on *NIX just the usual shebang). The path environment controls whether things are seen. So the first arg to Popen is just the name of the script.

subprocess.Popen(['myscript.py', 'arg1', ...], ..., shell=True)

Jetty: HTTP ERROR: 503/ Service Unavailable

I had the same problem. I solved it by removing the line break from the xml file. I did

<operationBindings>
    <OperationBinding>
        <operationType>update</operationType>
        <operationId>makePdf</operationId>
        <serverObject>
            <className>com.myclass</className>
            <lookupStyle>new</lookupStyle>
        </serverObject>
        <serverMethod>makePdf</serverMethod>
    </OperationBinding>
</operationBindings>

instead of ...

<serverObject>
            <className>com.myclass
</className>
            <lookupStyle>new</lookupStyle>
</serverObject>

Renaming part of a filename

You'll need to learn how to use sed http://unixhelp.ed.ac.uk/CGI/man-cgi?sed

And also to use for so you can loop through your file entries http://www.cyberciti.biz/faq/bash-for-loop/

Your command will look something like this, I don't have a term beside me so I can't check

for i in `dir` do mv $i `echo $i | sed '/orig/new/g'`

Get the list of stored procedures created and / or modified on a particular date?

Here is the "newer school" version.

SELECT * FROM INFORMATION_SCHEMA.ROUTINES
WHERE ROUTINE_TYPE = N'PROCEDURE' and ROUTINE_SCHEMA = N'dbo' 
and CREATED = '20120927'

How do I parse JSON with Objective-C?

With the perspective of the OS X v10.7 and iOS 5 launches, probably the first thing to recommend now is NSJSONSerialization, Apple's supplied JSON parser. Use third-party options only as a fallback if you find that class unavailable at runtime.

So, for example:

NSData *returnedData = ...JSON data, probably from a web request...

// probably check here that returnedData isn't nil; attempting
// NSJSONSerialization with nil data raises an exception, and who
// knows how your third-party library intends to react?

if(NSClassFromString(@"NSJSONSerialization"))
{
    NSError *error = nil;
    id object = [NSJSONSerialization
                      JSONObjectWithData:returnedData
                      options:0
                      error:&error];

    if(error) { /* JSON was malformed, act appropriately here */ }

    // the originating poster wants to deal with dictionaries;
    // assuming you do too then something like this is the first
    // validation step:
    if([object isKindOfClass:[NSDictionary class]])
    {
        NSDictionary *results = object;
        /* proceed with results as you like; the assignment to
        an explicit NSDictionary * is artificial step to get 
        compile-time checking from here on down (and better autocompletion
        when editing). You could have just made object an NSDictionary *
        in the first place but stylistically you might prefer to keep
        the question of type open until it's confirmed */
    }
    else
    {
        /* there's no guarantee that the outermost object in a JSON
        packet will be a dictionary; if we get here then it wasn't,
        so 'object' shouldn't be treated as an NSDictionary; probably
        you need to report a suitable error condition */
    }
}
else
{
    // the user is using iOS 4; we'll need to use a third-party solution.
    // If you don't intend to support iOS 4 then get rid of this entire
    // conditional and just jump straight to
    // NSError *error = nil;
    // [NSJSONSerialization JSONObjectWithData:...
}

Installing Java 7 (Oracle) in Debian via apt-get

Managed to get answer after do some google..

echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | tee -a /etc/apt/sources.list
echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | tee -a /etc/apt/sources.list
apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886
apt-get update
# Java 7
apt-get install oracle-java7-installer
# For Java 8 command is:
apt-get install oracle-java8-installer

How to refresh a page with jQuery by passing a parameter to URL

Click these links to see these more flexible and robust solutions. They're answers to a similar question:

These allow you to programmatically set the parameter, and, unlike the other hacks suggested for this question, won't break for URLs that already have a parameter, or if something else isn't quite what you thought might happen.

Android: textview hyperlink

You could have two separate TextViews and you could align them accordingly in your layout if needed:

    Text1.setText(
        Html.fromHtml(
            "<a href=\"http://www.google.com\">google</a> "));
    Text1.setMovementMethod(LinkMovementMethod.getInstance());

    Text2.setText(
            Html.fromHtml(
                "<a href=\"http://www.stackoverflow.com\">stackoverflow</a> "));
    Text2.setMovementMethod(LinkMovementMethod.getInstance());

Then if you want to strip the "link underline". Create a class:

public class URLSpanNoUnderline extends URLSpan {
    public URLSpanNoUnderline(String url) {
        super(url);
    }
    @Override public void updateDrawState(TextPaint ds) {
        super.updateDrawState(ds);
        ds.setUnderlineText(false);
        }
}

Then add this method in your main Activity class where you have the TextViews

private void stripUnderlines(TextView textView) {
    Spannable s = new SpannableString(textView.getText());
    URLSpan[] spans = s.getSpans(0, s.length(), URLSpan.class);
    for (URLSpan span: spans) {
        int start = s.getSpanStart(span);
        int end = s.getSpanEnd(span);
        s.removeSpan(span);
        span = new URLSpanNoUnderline(span.getURL());
        s.setSpan(span, start, end, 0);
    }
    textView.setText(s);
}

And then just call this after you initialised the TextViews (in your onCreate):

stripUnderlines(Text1);
stripUnderlines(Text2);

Writing new lines to a text file in PowerShell

Try this;

Add-Content -path $logpath @"
$((get-date).tostring()) Error $keyPath $value
key $key expected: $policyValue
local value is:  $localValue
"@

How to get the number of threads in a Java process

Using Linux Top command

top -H -p (process id)

you could get process id of one program by this method :

ps aux | grep (your program name)

for example :

ps aux | grep user.py

How do I view an older version of an SVN file?

To directly answer the question of how to "get a copy of that file":

svn cat -r 666 file > file_r666

then you can view the newly created file_r666 with any viewer or comparison program, e.g.

kompare file_r666 file

nicely shows the differences.

I posted the answer because the accepted answer's commands do actually not give a copy of the file and because svn cat -r 666 file | vim does not work with my system (Vim: Error reading input, exiting...)

Get list of certificates from the certificate store in C#

X509Store store = new X509Store(StoreName.My, StoreLocation.LocalMachine);

store.Open(OpenFlags.ReadOnly);

foreach (X509Certificate2 certificate in store.Certificates){
    //TODO's
}

What is a Java String's default initial value?

The answer is - it depends.

Is the variable an instance variable / class variable ? See this for more details.

The list of default values can be found here.

Dynamic function name in javascript?

You can use Object.defineProperty as noted in the MDN JavaScript Reference:

var myName = "myName";
var f = function () { return true; };
Object.defineProperty(f, 'name', {value: myName, writable: false});

How to update (append to) an href in jquery?

jQuery 1.4 has a new feature for doing this, and it rules. I've forgotten what it's called, but you use it like this:

$("a.directions-link").attr("href", function(i, href) {
  return href + '?q=testing';
});

That loops over all the elements too, so no need for $.each

How do I remove carriage returns with Ruby?

You can use this :

my_string.strip.gsub(/\s+/, ' ')

Visual Studio C# IntelliSense not automatically displaying

I also faced the same issue but in VS2013.

I did the below way to fix, It was worked fine.

  1. Close all the opened Visual studio instance.

  2. Then, go to "Developer command prompt" from visual studio tools,

  3. Type it as devenv.exe /resetuserdata

  4. Restart the machine, Open the Visual studio then It will ask you to choose the development settings from initial onwards, thereafter open any solution/project. You'll be amazed.

Hope, it might helps you :)

What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?

Note that what you are trying to do is calculate the integer log2 of an integer,

#include <stdio.h>
#include <stdlib.h>

unsigned int
Log2(unsigned long x)
{
    unsigned long n = x;
    int bits = sizeof(x)*8;
    int step = 1; int k=0;
    for( step = 1; step < bits; ) {
        n |= (n >> step);
        step *= 2; ++k;
    }
    //printf("%ld %ld\n",x, (x - (n >> 1)) );
    return(x - (n >> 1));
}

Observe that you can attempt to search more than 1 bit at a time.

unsigned int
Log2_a(unsigned long x)
{
    unsigned long n = x;
    int bits = sizeof(x)*8;
    int step = 1;
    int step2 = 0;
    //observe that you can move 8 bits at a time, and there is a pattern...
    //if( x>1<<step2+8 ) { step2+=8;
        //if( x>1<<step2+8 ) { step2+=8;
            //if( x>1<<step2+8 ) { step2+=8;
            //}
        //}
    //}
    for( step2=0; x>1L<<step2+8; ) {
        step2+=8;
    }
    //printf("step2 %d\n",step2);
    for( step = 0; x>1L<<(step+step2); ) {
        step+=1;
        //printf("step %d\n",step+step2);
    }
    printf("log2(%ld) %d\n",x,step+step2);
    return(step+step2);
}

This approach uses a binary search

unsigned int
Log2_b(unsigned long x)
{
    unsigned long n = x;
    unsigned int bits = sizeof(x)*8;
    unsigned int hbit = bits-1;
    unsigned int lbit = 0;
    unsigned long guess = bits/2;
    int found = 0;

    while ( hbit-lbit>1 ) {
        //printf("log2(%ld) %d<%d<%d\n",x,lbit,guess,hbit);
        //when value between guess..lbit
        if( (x<=(1L<<guess)) ) {
           //printf("%ld < 1<<%d %ld\n",x,guess,1L<<guess);
            hbit=guess;
            guess=(hbit+lbit)/2;
            //printf("log2(%ld) %d<%d<%d\n",x,lbit,guess,hbit);
        }
        //when value between hbit..guess
        //else
        if( (x>(1L<<guess)) ) {
            //printf("%ld > 1<<%d %ld\n",x,guess,1L<<guess);
            lbit=guess;
            guess=(hbit+lbit)/2;
            //printf("log2(%ld) %d<%d<%d\n",x,lbit,guess,hbit);
        }
    }
    if( (x>(1L<<guess)) ) ++guess;
    printf("log2(x%ld)=r%d\n",x,guess);
    return(guess);
}

Another binary search method, perhaps more readable,

unsigned int
Log2_c(unsigned long x)
{
    unsigned long v = x;
    unsigned int bits = sizeof(x)*8;
    unsigned int step = bits;
    unsigned int res = 0;
    for( step = bits/2; step>0; )
    {
        //printf("log2(%ld) v %d >> step %d = %ld\n",x,v,step,v>>step);
        while ( v>>step ) {
            v>>=step;
            res+=step;
            //printf("log2(%ld) step %d res %d v>>step %ld\n",x,step,res,v);
        }
        step /= 2;
    }
    if( (x>(1L<<res)) ) ++res;
    printf("log2(x%ld)=r%ld\n",x,res);
    return(res);
}

And because you will want to test these,

int main()
{
    unsigned long int x = 3;
    for( x=2; x<1000000000; x*=2 ) {
        //printf("x %ld, x+1 %ld, log2(x+1) %d\n",x,x+1,Log2(x+1));
        printf("x %ld, x+1 %ld, log2_a(x+1) %d\n",x,x+1,Log2_a(x+1));
        printf("x %ld, x+1 %ld, log2_b(x+1) %d\n",x,x+1,Log2_b(x+1));
        printf("x %ld, x+1 %ld, log2_c(x+1) %d\n",x,x+1,Log2_c(x+1));
    }
    return(0);
}

C pointers and arrays: [Warning] assignment makes pointer from integer without a cast

What are you doing: (I am using bytes instead of in for better reading)

You start with int *ap and so on, so your (your computers) memory looks like this:

-------------- memory used by some one else --------
000: ?
001: ?
...
098: ?
099: ?
-------------- your memory  --------
100: something          <- here is *ap
101: 41                 <- here starts a[] 
102: 42
103: 43
104: 44
105: 45
106: something          <- here waits x

lets take a look waht happens when (print short cut for ...print("$d", ...)

print a[0]  -> 41   //no surprise
print a     -> 101  // because a points to the start of the array
print *a    -> 41   // again the first element of array
print a+1   -> guess? 102
print *(a+1)    -> whats behind 102? 42 (we all love this number)

and so on, so a[0] is the same as *a, a[1] = *(a+1), ....

a[n] just reads easier.

now, what happens at line 9?

ap=a[4] // we know a[4]=*(a+4) somehow *105 ==>  45 
// warning! converting int to pointer!
-------------- your memory  --------
100: 45         <- here is *ap now 45

x = *ap;   // wow ap is 45 -> where is 45 pointing to?
-------------- memory used by some one else --------
bang!      // dont touch neighbours garden

So the "warning" is not just a warning it's a severe error.

PostgreSQL create table if not exists

There is no CREATE TABLE IF NOT EXISTS... but you can write a simple procedure for that, something like:

CREATE OR REPLACE FUNCTION prc_create_sch_foo_table() RETURNS VOID AS $$
BEGIN

EXECUTE 'CREATE TABLE /* IF NOT EXISTS add for PostgreSQL 9.1+ */ sch.foo (
                    id serial NOT NULL, 
                    demo_column varchar NOT NULL, 
                    demo_column2 varchar NOT NULL,
                    CONSTRAINT pk_sch_foo PRIMARY KEY (id));
                   CREATE INDEX /* IF NOT EXISTS add for PostgreSQL 9.5+ */ idx_sch_foo_demo_column ON sch.foo(demo_column);
                   CREATE INDEX /* IF NOT EXISTS add for PostgreSQL 9.5+ */ idx_sch_foo_demo_column2 ON sch.foo(demo_column2);'
               WHERE NOT EXISTS(SELECT * FROM information_schema.tables 
                        WHERE table_schema = 'sch' 
                            AND table_name = 'foo');

         EXCEPTION WHEN null_value_not_allowed THEN
           WHEN duplicate_table THEN
           WHEN others THEN RAISE EXCEPTION '% %', SQLSTATE, SQLERRM;

END; $$ LANGUAGE plpgsql;

Does JavaScript have the interface type (such as Java's 'interface')?

You need interfaces in Java since it is statically typed and the contract between classes should be known during compilation. In JavaScript it is different. JavaScript is dynamically typed; it means that when you get the object you can just check if it has a specific method and call it.

PHP/Apache: PHP Fatal error: Call to undefined function mysql_connect()

In case anyone else faces this, it's a case of PHP not having access to the mysql client libraries. Having a MySQL server on the system is not the correct fix. Fix for ubuntu (and PHP 5):

sudo apt-get install php5-mysql

After installing the client, the webserver should be restarted. In case you're using apache, the following should work:

sudo service apache2 restart

Intel X86 emulator accelerator (HAXM installer) VT/NX not enabled

In my case running Yosemite in VMWare Workstation 10.0.5 I had to:

1) Set kext to dev mode (might not be needed anymore .... try first without it)

sudo nvram boot-args="kext-dev-mode=1" 

Then reboot (power down VM) for step 2) below.

Details here: http://www.csell.net/2014/09/03/VTNX_Not_Enabled/

2) Add vhv.enable = "TRUE" to my VMX file and restart the VM

Details discussed here: https://communities.vmware.com/thread/416997?start=15&tstart=0

3) Install HAXM 1.1.1 as discussed above from the Intel 's site

(would love to post more links -> but have limit for 2 -> so vote for me so next time you will gert more .. :-))

Java TreeMap Comparator

you can swipe the key and the value. For example

        String[] k = {"Elena", "Thomas", "Hamilton", "Suzie", "Phil"};
        int[] v = {341, 273, 278, 329, 445};
        TreeMap<Integer,String>a=new TreeMap();
        for (int i = 0; i < k.length; i++) 
           a.put(v[i],k[i]);            
        System.out.println(a.firstEntry().getValue()+"\t"+a.firstEntry().getKey());
        a.remove(a.firstEntry().getKey());
        System.out.println(a.firstEntry().getValue()+"\t"+a.firstEntry().getKey());

Get to UIViewController from UIView?

I modified de answer so I can pass any view, button, label etc. to get it's parent UIViewController. Here is my code.

+(UIViewController *)viewController:(id)view {
    UIResponder *responder = view;
    while (![responder isKindOfClass:[UIViewController class]]) {
        responder = [responder nextResponder];
        if (nil == responder) {
            break;
        }
    }
    return (UIViewController *)responder;
}

Edit Swift 3 Version

class func viewController(_ view: UIView) -> UIViewController {
        var responder: UIResponder? = view
        while !(responder is UIViewController) {
            responder = responder?.next
            if nil == responder {
                break
            }
        }
        return (responder as? UIViewController)!
    }

Edit 2:- Swift Extention

extension UIView
{
    //Get Parent View Controller from any view
    func parentViewController() -> UIViewController {
        var responder: UIResponder? = self
        while !(responder is UIViewController) {
            responder = responder?.next
            if nil == responder {
                break
            }
        }
        return (responder as? UIViewController)!
    }
}

Using async/await with a forEach loop

Using Task, futurize, and a traversable List, you can simply do

async function printFiles() {
  const files = await getFiles();

  List(files).traverse( Task.of, f => readFile( f, 'utf-8'))
    .fork( console.error, console.log)
}

Here is how you'd set this up

import fs from 'fs';
import { futurize } from 'futurize';
import Task from 'data.task';
import { List } from 'immutable-ext';

const future = futurizeP(Task)
const readFile = future(fs.readFile)

Another way to have structured the desired code would be

const printFiles = files => 
  List(files).traverse( Task.of, fn => readFile( fn, 'utf-8'))
    .fork( console.error, console.log)

Or perhaps even more functionally oriented

// 90% of encodings are utf-8, making that use case super easy is prudent

// handy-library.js
export const readFile = f =>
  future(fs.readFile)( f, 'utf-8' )

export const arrayToTaskList = list => taskFn => 
  List(files).traverse( Task.of, taskFn ) 

export const readFiles = files =>
  arrayToTaskList( files, readFile )

export const printFiles = files => 
  readFiles(files).fork( console.error, console.log)

Then from the parent function

async function main() {
  /* awesome code with side-effects before */
  printFiles( await getFiles() );
  /* awesome code with side-effects after */
}

If you really wanted more flexibility in encoding, you could just do this (for fun, I'm using the proposed Pipe Forward operator )

import { curry, flip } from 'ramda'

export const readFile = fs.readFile 
  |> future,
  |> curry,
  |> flip

export const readFileUtf8 = readFile('utf-8')

PS - I didn't try this code on the console, might have some typos... "straight freestyle, off the top of the dome!" as the 90s kids would say. :-p

What is the best way to find the users home directory in Java?

Actually with Java 8 the right way is to use:

System.getProperty("user.home");

The bug JDK-6519127 has been fixed and the "Incompatibilities between JDK 8 and JDK 7" section of the release notes states:

Area: Core Libs / java.lang

Synopsis

The steps used to determine the user's home directory on Windows have changed to follow the Microsoft recommended approach. This change might be observable on older editions of Windows or where registry settings or environment variables are set to other directories. Nature of Incompatibility

behavioral RFE

6519127

Despite the question being old I leave this for future reference.

How to extract elements from a list using indices in Python?

Use Numpy direct array indexing, as in MATLAB, Julia, ...

a = [10, 11, 12, 13, 14, 15];
s = [1, 2, 5] ;

import numpy as np
list(np.array(a)[s])
# [11, 12, 15]

Better yet, just stay with Numpy arrays

a = np.array([10, 11, 12, 13, 14, 15])
a[s]
#array([11, 12, 15])

Using jQuery to test if an input has focus

I'm not entirely sure what you're after but this sounds like it can be achieved by storing the state of the input elements (or the div?) as a variable:

$('div').each(function(){

    var childInputHasFocus = false;

    $(this).hover(function(){
        if (childInputHasFocus) {
            // do something
        } else { }
    }, function() {
        if (childInputHasFocus) {
            // do something
        } else { }
    });

    $('input', this)
        .focus(function(){
            childInputHasFocus = true;
        })
        .blur(function(){
            childInputHasFocus = false;
        });
});

Predict() - Maybe I'm not understanding it

Thanks Hong, that was exactly the problem I was running into. The error you get suggests that the number of rows is wrong, but the problem is actually that the model has been trained using a command that ends up with the wrong names for parameters.

This is really a critical detail that is entirely non-obvious for lm and so on. Some of the tutorial make reference to doing lines like lm(olive$Area@olive$Palmitic) - ending up with variable names of olive$Area NOT Area, so creating an entry using anewdata<-data.frame(Palmitic=2) can't then be used. If you use lm(Area@Palmitic,data=olive) then the variable names are right and prediction works.

The real problem is that the error message does not indicate the problem at all:

Warning message: 'anewdata' had 1 rows but variable(s) found to have X rows

Branch from a previous commit using Git

You can create the branch via a hash:

git branch branchname <sha1-of-commit>

Or by using a symbolic reference:

git branch branchname HEAD~3

To checkout the branch when creating it, use

git checkout -b branchname <sha1-of-commit or HEAD~3>

Does it matter what extension is used for SQLite database files?

If you have settled on a particular set of tools to access / modify your databases, I would go with whatever extension they expect you to use. This will avoid needless friction when doing development tasks.

For instance, SQLiteStudio v3.1.1 defaults to looking for files with the following extensions:

enter image description here

(db|sdb|sqlite|db3|s3db|sqlite3|sl3|db2|s2db|sqlite2|sl2)

If necessary for deployment your installation mechanism could rename the file if obscuring the file type seems useful to you (as some other answers have suggested). Filename requirements for development and deployment can be different.

Permission to write to the SD card

You're right that the SD Card directory is /sdcard but you shouldn't be hard coding it. Instead, make a call to Environment.getExternalStorageDirectory() to get the directory:

File sdDir = Environment.getExternalStorageDirectory();

If you haven't done so already, you will need to give your app the correct permission to write to the SD Card by adding the line below to your Manifest:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Select records from today, this week, this month php mysql

Try using date and time functions (MONTH(), YEAR(), DAY(), MySQL Manual)

This week:

SELECT * FROM jokes WHERE WEEKOFYEAR(date)=WEEKOFYEAR(NOW());

Last week:

SELECT * FROM jokes WHERE WEEKOFYEAR(date)=WEEKOFYEAR(NOW())-1;

Extracting specific columns from a data frame

You can also use the sqldf package which performs selects on R data frames as :

df1 <- sqldf("select A, B, E from df")

This gives as the output a data frame df1 with columns: A, B ,E.

MongoDB: How to update multiple documents with a single command?

I've created a way to do this with a better interface.

  • db.collection.find({ ... }).update({ ... }) -- multi update
  • db.collection.find({ ... }).replace({ ... }) -- single replacement
  • db.collection.find({ ... }).upsert({ ... }) -- single upsert
  • db.collection.find({ ... }).remove() -- multi remove

You can also apply limit, skip, sort to the updates and removes by chaining them in beforehand.

If you are interested, check out Mongo-Hacker

How to host material icons offline?

Method 2. Self hosting Developer Guide

Download the latest release from github (assets: zip file), unzip, and copy the font folder, containing the material design icons files, into your local project -- https://github.com/google/material-design-icons/releases

You only need to use the font folder from the archive: it contains the icons fonts in the different formats (for multiple browser support) and boilerplate css.

  • Replace the source in the url attribute of @font-face, with the relative path to the iconfont folder in your local project, (where the font files are located) eg. url("iconfont/MaterialIcons-Regular.ttf")
@font-face {
   font-family: 'Material Icons';
   font-style: normal;
   font-weight: 400;
   src: url(iconfont/MaterialIcons-Regular.eot); /* For IE6-8 */
   src: local('Material Icons'),
        local('MaterialIcons-Regular'),
        url(iconfont/MaterialIcons-Regular.woff2) format('woff2'),
        url(iconfont/MaterialIcons-Regular.woff) format('woff'),
        url(iconfont/MaterialIcons-Regular.ttf) format('truetype');
}

.material-icons {
  font-family: 'Material Icons';
  font-weight: normal;
  font-style: normal;
  font-size: 24px;  /* Preferred icon size */
  display: inline-block;
  line-height: 1;
  text-transform: none;
  letter-spacing: normal;
  word-wrap: normal;
  white-space: nowrap;
  direction: ltr;

  /* Support for all WebKit browsers. */
  -webkit-font-smoothing: antialiased;
  /* Support for Safari and Chrome. */
  text-rendering: optimizeLegibility;

  /* Support for Firefox. */
  -moz-osx-font-smoothing: grayscale;

  /* Support for IE. */
  font-feature-settings: 'liga';
}

<i class="material-icons">face</i>

NPM / Bower Packages

Google officially has a Bower and NPM dependency option -- follow Material Icons Guide 1

Using bower : bower install material-design-icons --save

Using NPM : npm install material-design-icons --save

Material Icons : Alternatively look into Material design icon font and CSS framework for self hosting the icons, from @marella's https://marella.me/material-icons/


Note

It seems google has the project on low maintenance mode. The last release was, at time of writing, 3 years ago!

There are several issues on GitHub regarding this, but I'd like to refer to @cyberalien comment on the issue Is this project actively maintained? #951 where it refers several community projects that forked and continue maintaining material icons.


Git, How to reset origin/master to a commit?

origin/xxx branches are always pointer to a remote. You cannot check them out as they're not pointer to your local repository (you only checkout the commit. That's why you won't see the name written in the command line interface branch marker, only the commit hash).

What you need to do to update the remote is to force push your local changes to master:

git checkout master
git reset --hard e3f1e37
git push --force origin master
# Then to prove it (it won't print any diff)
git diff master..origin/master

How to redirect verbose garbage collection output to a file?

From the output of java -X:

    -Xloggc:<file>    log GC status to a file with time stamps

Documented here:

-Xloggc:filename

Sets the file to which verbose GC events information should be redirected for logging. The information written to this file is similar to the output of -verbose:gc with the time elapsed since the first GC event preceding each logged event. The -Xloggc option overrides -verbose:gc if both are given with the same java command.

Example:

    -Xloggc:garbage-collection.log

So the output looks something like this:

0.590: [GC 896K->278K(5056K), 0.0096650 secs]
0.906: [GC 1174K->774K(5056K), 0.0106856 secs]
1.320: [GC 1670K->1009K(5056K), 0.0101132 secs]
1.459: [GC 1902K->1055K(5056K), 0.0030196 secs]
1.600: [GC 1951K->1161K(5056K), 0.0032375 secs]
1.686: [GC 1805K->1238K(5056K), 0.0034732 secs]
1.690: [Full GC 1238K->1238K(5056K), 0.0631661 secs]
1.874: [GC 62133K->61257K(65060K), 0.0014464 secs]

How to change UINavigationBar background color from the AppDelegate

You can use [[UINavigationBar appearance] setTintColor:myColor];

Since iOS 7 you need to set [[UINavigationBar appearance] setBarTintColor:myColor]; and also [[UINavigationBar appearance] setTranslucent:NO].

[[UINavigationBar appearance] setBarTintColor:myColor];
[[UINavigationBar appearance] setTranslucent:NO];

how to get param in method post spring mvc?

When I want to get all the POST params I am using the code below,

@RequestMapping(value = "/", method = RequestMethod.POST)
public ViewForResponseClass update(@RequestBody AClass anObject) {
    // Source..
}

I am using the @RequestBody annotation for post/put/delete http requests instead of the @RequestParam which reads the GET parameters.

How do I automatically update a timestamp in PostgreSQL

Updating timestamp, only if the values changed

Based on E.J's link and add a if statement from this link (https://stackoverflow.com/a/3084254/1526023)

CREATE OR REPLACE FUNCTION update_modified_column()
RETURNS TRIGGER AS $$
BEGIN
   IF row(NEW.*) IS DISTINCT FROM row(OLD.*) THEN
      NEW.modified = now(); 
      RETURN NEW;
   ELSE
      RETURN OLD;
   END IF;
END;
$$ language 'plpgsql';

How to set <Text> text to upper case in react native

iOS textTransform support has been added to react-native in 0.56 version. Android textTransform support has been added in 0.59 version. It accepts one of these options:

  • none
  • uppercase
  • lowercase
  • capitalize

The actual iOS commit, Android commit and documentation

Example:

<View>
  <Text style={{ textTransform: 'uppercase'}}>
    This text should be uppercased.
  </Text>
  <Text style={{ textTransform: 'capitalize'}}>
    Mixed:{' '}
    <Text style={{ textTransform: 'lowercase'}}>
      lowercase{' '}
    </Text>
  </Text>
</View>

How do I replicate a \t tab space in HTML?

HTML doesn't have escape characters (as it doesn't use escape-semantics for reserved characters, instead you use SGML entities: &amp;, &lt;, &gt; and &quot;).

SGML does not have a named-entity for the tab character as it exists in most character sets (i.e. 0x09 in ASCII and UTF-8), rendering it completely unnecessary (i.e. simply press the Tab key on your keyboard). If you're working with code that generates HTML (e.g. a server-side application, e.g. ASP.NET, PHP or Perl, then you might need to escape it then, but only because the server-side language demands it - it has nothing to do with HTML, like so:

echo "<pre>\t\tTABS!\t\t</pre>";

But, you can use SGML entities to represent any ISO-8859-1 character by hexadecimal value, e.g. &#09; for a tab character.

ServletException, HttpServletResponse and HttpServletRequest cannot be resolved to a type

As a reason of this problem, some code is broken or undefined.You may see an error in a java class such as "The type javax.servlet.http.HttpSession cannot be resolved. It is indirectly referenced from required .class files". you shuold download " javax.servlet.jar" as mentioned before. Then configure your project build path, add the javax.servlet.jar as an external jar.I hope it fixes the problem.At least it worked for me.

How to add element into ArrayList in HashMap

First you have to add an ArrayList to the Map

ArrayList<Item> al = new ArrayList<Item>();

Items.add("theKey", al); 

then you can add an item to the ArrayLIst that is inside the Map like this:

Items.get("theKey").add(item);  // item is an object of type Item

git am error: "patch does not apply"

What is a patch?

A patch is little more (see below) than a series of instructions: "add this here", "remove that there", "change this third thing to a fourth". That's why git tells you:

The copy of the patch that failed is found in:
c:/.../project2/.git/rebase-apply/patch

You can open that patch in your favorite viewer or editor, open the files-to-be-changed in your favorite editor, and "hand apply" the patch, using what you know (and git does not) to figure out how "add this here" is to be done when the files-to-be-changed now look little or nothing like what they did when they were changed earlier, with those changes delivered to you as a patch.

A little more

A three-way merge introduces that "little more" information than the plain "series of instructions": it tells you what the original version of the file was as well. If your repository has the original version, your git can compare what you did to a file, to what the patch says to do to the file.

As you saw above, if you request the three-way merge, git can't find the "original version" in the other repository, so it can't even attempt the three-way merge. As a result you get no conflict markers, and you must do the patch-application by hand.

Using --reject

When you have to apply the patch by hand, it's still possible that git can apply most of the patch for you automatically and leave only a few pieces to the entity with the ability to reason about the code (or whatever it is that needs patching). Adding --reject tells git to do that, and leave the "inapplicable" parts of the patch in rejection files. If you use this option, you must still hand-apply each failing patch, and figure out what to do with the rejected portions.

Once you have made the required changes, you can git add the modified files and use git am --continue to tell git to commit the changes and move on to the next patch.

What if there's nothing to do?

Since we don't have your code, I can't tell if this is the case, but sometimes, you wind up with one of the patches saying things that amount to, e.g., "fix the spelling of a word on line 42" when the spelling there was already fixed.

In this particular case, you, having looked at the patch and the current code, should say to yourself: "aha, this patch should just be skipped entirely!" That's when you use the other advice git already printed:

If you prefer to skip this patch, run "git am --skip" instead.

If you run git am --skip, git will skip over that patch, so that if there were five patches in the mailbox, it will end up adding just four commits, instead of five (or three instead of five if you skip twice, and so on).

Does C++ support 'finally' blocks? (And what's this 'RAII' I keep hearing about?)

why is it that even managed languages provide a finally-block despite resources being deallocated automatically by the garbage collector anyway?

Actually, languages based on Garbage collectors need "finally" more. A garbage collector does not destroy your objects in a timely manner, so it can not be relied upon to clean up non-memory related issues correctly.

In terms of dynamically-allocated data, many would argue that you should be using smart-pointers.

However...

RAII moves the responsibility of exception safety from the user of the object to the designer

Sadly this is its own downfall. Old C programming habits die hard. When you're using a library written in C or a very C style, RAII won't have been used. Short of re-writing the entire API front-end, that's just what you have to work with. Then the lack of "finally" really bites.

Visually managing MongoDB documents and collections

Here are some popular MongoDB GUI administration tools:

Open source

  • dbKoda - cross-platform, tabbed editor with auto-complete, syntax highlighting and code formatting (plus auto-save, something Studio 3T doesn't support), visual tools (explain plan, real-time performance dashboard, query and aggregation pipeline builder), profiling manager, storage analyzer, index advisor, convert MongoDB commands to Node.js syntax etc. Lacks in-place document editing and the ability to switch themes.

    dbKoda screenshot

  • Nosqlclient - multiple shell output tabs, autocomplete, schema analyzer, index management, user/role management, live monitoring, and other features. Electron/Meteor.js-based, actively developed on GitHub.

  • adminMongo - web-based or Electron app. Supports server monitoring and document editing.

Closed source

  • NoSQLBoosterfull-featured shell-centric cross-platform GUI tool for MongoDB v2.2-4. Free, Personal, and Commercial editions (feature comparison matrix).
  • MongoDB Compass – provides a graphical user interface that allows you to visualize your schema and perform ad-hoc find queries against the database – all with zero knowledge of MongoDB's query language. Developed by MongoDB, Inc. No update queries or access to the shell.
  • Studio 3T, formerly MongoChef – a multi-platform in-place data browser and editor desktop GUI for MongoDB (Core version is free for personal and non-commercial use). Last commit: 2017-Jul-24
  • Robo 3T – acquired by Studio 3T. A shell-centric cross-platform open source MongoDB management tool. Shell-related features only, e.g. multiple shells and results, autocomplete. No export/ import or other features are mentioned. Last commit: 2017-Jul-04

  • HumongouS.io – web-based interface with CRUD features, a chart builder and some collaboration capabilities. 14-day trial.

  • Database Master – a Windows based MongoDB Management Studio, supports also RDBMS. (not free)
  • SlamData - an open source web-based user-interface that allows you to upload and download data, run queries, build charts, explore data.

Abandoned projects

  • RockMongo – a MongoDB administration tool, written in PHP5. Allegedly the best in the PHP world. Similar to PHPMyAdmin. Last version: 2015-Sept-19
  • Fang of Mongo – a web-based UI built with Django and jQuery. Last commit: 2012-Jan-26, in a forked project.
  • Opricot – a browser-based MongoDB shell written in PHP. Latest version: 2010-Sep-21
  • Futon4Mongo – a clone of the CouchDB Futon web interface for MongoDB. Last commit: 2010-Oct-09
  • MongoVUE – an elegant GUI desktop application for Windows. Free and non-free versions. Latest version: 2014-Jan-20
  • UMongo – a full-featured open-source MongoDB server administration tool for Linux, Windows, Mac; written in Java. Last commit 2014-June
  • Mongo3 – a Ruby/Sinatra-based interface for cluster management. Last commit: Apr 16, 2013

Two Decimal places using c#

For only to display, property of String can be used as following..

double value = 123.456789;
String.Format("{0:0.00}", value);

Using System.Math.Round. This value can be assigned to others or manipulated as required..

double value = 123.456789;
System.Math.Round(value, 2);

ImportError: No module named - Python

This is if you are building a package and you are finding error in imports. I learnt it the hard way.The answer isn't to add the package to python path or to do it programatically (what if your module gets installed and your command adds it again?) thats a bad way.

The right thing to do is: 1) Use virtualenv pyvenv-3.4 or something similar 2) Activate the development mode - $python setup.py develop

Index (zero based) must be greater than or equal to zero

Your second String.Format uses {2} as a placeholder but you're only passing in one argument, so you should use {0} instead.

Change this:

String.Format("{2}", reader.GetString(0));

To this:

String.Format("{0}", reader.GetString(2));

How do I show the value of a #define at compile-time?

BOOST_VERSION is defined in the boost header file version.hpp.

VBA: How to delete filtered rows in Excel?

As an alternative to using UsedRange or providing an explicit range address, the AutoFilter.Range property can also specify the affected range.

ActiveSheet.AutoFilter.Range.Offset(1,0).Rows.SpecialCells(xlCellTypeVisible).Delete(xlShiftUp)

As used here, Offset causes the first row after the AutoFilter range to also be deleted. In order to avoid that, I would try using .Resize() after .Offset().

jQuery: How to capture the TAB keypress within a Textbox

Suppose you have TextBox with Id txtName

$("[id*=txtName]").on('keydown', function(e) { 
  var keyCode = e.keyCode || e.which; 
  if (keyCode == 9) {
     e.preventDefault();
     alert('Tab Pressed');
 }
}); 

Why does the preflight OPTIONS request of an authenticated CORS request work in Chrome but not Firefox?

Why does it work in Chrome and not Firefox?

The W3 spec for CORS preflight requests clearly states that user credentials should be excluded. There is a bug in Chrome and WebKit where OPTIONS requests returning a status of 401 still send the subsequent request.

Firefox has a related bug filed that ends with a link to the W3 public webapps mailing list asking for the CORS spec to be changed to allow authentication headers to be sent on the OPTIONS request at the benefit of IIS users. Basically, they are waiting for those servers to be obsoleted.

How can I get the OPTIONS request to send and respond consistently?

Simply have the server (API in this example) respond to OPTIONS requests without requiring authentication.

Kinvey did a good job expanding on this while also linking to an issue of the Twitter API outlining the catch-22 problem of this exact scenario interestingly a couple weeks before any of the browser issues were filed.

Get list of data-* attributes using javascript / jQuery

You can just iterate over the data attributes like any other object to get keys and values, here's how to do it with $.each:

    $.each($('#myEl').data(), function(key, value) {
        console.log(key);
        console.log(value);
    });

Make an image follow mouse pointer

by using jquery to register .mousemove to document to change the image .css left and top to event.pageX and event.pageY.

example as below http://jsfiddle.net/BfLAh/1/

_x000D_
_x000D_
$(document).mousemove(function(e) {
  $("#follow").css({
    left: e.pageX,
    top: e.pageY
  });
});
_x000D_
#follow {
  position: absolute;
  text-align: center;
}
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="follow"><img src="https://placekitten.com/96/140" /><br>Kitteh</br>
</div>
_x000D_
_x000D_
_x000D_

updated to follow slowly

http://jsfiddle.net/BfLAh/3/

for the orientation , you need to get the current css left and css top and compare with event.pageX and event.pageY , then set the image orientation with

-webkit-transform: rotate(-90deg); 
-moz-transform: rotate(-90deg); 

for the speed , you can set the jquery .animation duration to certain amount.

What is the difference between const and readonly in C#?

This explains it. Summary: const must be initialized at declaration time, readonly can be initialized on the constructor (and thus have a different value depending on the constructor used).

EDIT: See Gishu's gotcha above for the subtle difference

Create a new object from type parameter in generic class

All type information is erased in JavaScript side and therefore you can't new up T just like @Sohnee states, but I would prefer having typed parameter passed in to constructor:

class A {
}

class B<T> {
    Prop: T;
    constructor(TCreator: { new (): T; }) {
        this.Prop = new TCreator();
    }
}

var test = new B<A>(A);

How to check whether a pandas DataFrame is empty?

To see if a dataframe is empty, I argue that one should test for the length of a dataframe's columns index:

if len(df.columns) == 0: 1

Reason:

According to the Pandas Reference API, there is a distinction between:

  • an empty dataframe with 0 rows and 0 columns
  • an empty dataframe with rows containing NaN hence at least 1 column

Arguably, they are not the same. The other answers are imprecise in that df.empty, len(df), or len(df.index) make no distinction and return index is 0 and empty is True in both cases.

Examples

Example 1: An empty dataframe with 0 rows and 0 columns

In [1]: import pandas as pd
        df1 = pd.DataFrame()
        df1
Out[1]: Empty DataFrame
        Columns: []
        Index: []

In [2]: len(df1.index)  # or len(df1)
Out[2]: 0

In [3]: df1.empty
Out[3]: True

Example 2: A dataframe which is emptied to 0 rows but still retains n columns

In [4]: df2 = pd.DataFrame({'AA' : [1, 2, 3], 'BB' : [11, 22, 33]})
        df2
Out[4]:    AA  BB
        0   1  11
        1   2  22
        2   3  33

In [5]: df2 = df2[df2['AA'] == 5]
        df2
Out[5]: Empty DataFrame
        Columns: [AA, BB]
        Index: []

In [6]: len(df2.index)  # or len(df2)
Out[6]: 0

In [7]: df2.empty
Out[7]: True

Now, building on the previous examples, in which the index is 0 and empty is True. When reading the length of the columns index for the first loaded dataframe df1, it returns 0 columns to prove that it is indeed empty.

In [8]: len(df1.columns)
Out[8]: 0

In [9]: len(df2.columns)
Out[9]: 2

Critically, while the second dataframe df2 contains no data, it is not completely empty because it returns the amount of empty columns that persist.

Why it matters

Let's add a new column to these dataframes to understand the implications:

# As expected, the empty column displays 1 series
In [10]: df1['CC'] = [111, 222, 333]
         df1
Out[10]:    CC
         0 111
         1 222
         2 333
In [11]: len(df1.columns)
Out[11]: 1

# Note the persisting series with rows containing `NaN` values in df2
In [12]: df2['CC'] = [111, 222, 333]
         df2
Out[12]:    AA  BB   CC
         0 NaN NaN  111
         1 NaN NaN  222
         2 NaN NaN  333
In [13]: len(df2.columns)
Out[13]: 3

It is evident that the original columns in df2 have re-surfaced. Therefore, it is prudent to instead read the length of the columns index with len(pandas.core.frame.DataFrame.columns) to see if a dataframe is empty.

Practical solution

# New dataframe df
In [1]: df = pd.DataFrame({'AA' : [1, 2, 3], 'BB' : [11, 22, 33]})
        df
Out[1]:    AA  BB
        0   1  11
        1   2  22
        2   3  33

# This data manipulation approach results in an empty df
# because of a subset of values that are not available (`NaN`)
In [2]: df = df[df['AA'] == 5]
        df
Out[2]: Empty DataFrame
        Columns: [AA, BB]
        Index: []

# NOTE: the df is empty, BUT the columns are persistent
In [3]: len(df.columns)
Out[3]: 2

# And accordingly, the other answers on this page
In [4]: len(df.index)  # or len(df)
Out[4]: 0

In [5]: df.empty
Out[5]: True
# SOLUTION: conditionally check for empty columns
In [6]: if len(df.columns) != 0:  # <--- here
            # Do something, e.g. 
            # drop any columns containing rows with `NaN`
            # to make the df really empty
            df = df.dropna(how='all', axis=1)
        df
Out[6]: Empty DataFrame
        Columns: []
        Index: []

# Testing shows it is indeed empty now
In [7]: len(df.columns)
Out[7]: 0

Adding a new data series works as expected without the re-surfacing of empty columns (factually, without any series that were containing rows with only NaN):

In [8]: df['CC'] = [111, 222, 333]
         df
Out[8]:    CC
         0 111
         1 222
         2 333
In [9]: len(df.columns)
Out[9]: 1

<button> vs. <input type="button" />. Which to use?

Inside a <button> element you can put content, like text or images.

<button type="button">Click Me!</button> 

This is the difference between this element and buttons created with the <input> element.

SQLite error 'attempt to write a readonly database' during insert?

This can be caused by SELinux. If you don't want to disable SELinux completely, you need to set the db directory fcontext to httpd_sys_rw_content_t.

semanage fcontext -a -t httpd_sys_rw_content_t "/var/www/railsapp/db(/.*)?"
restorecon -v /var/www/railsapp/db

How do I delete an item or object from an array using ng-click?

Here is another answer. I hope it will help.

<a class="btn" ng-click="delete(item)">Delete</a>

$scope.delete(item){
 var index = this.list.indexOf(item);
                this.list.splice(index, 1);   
}

array.splice(start)
array.splice(start, deleteCount)
array.splice(start, deleteCount, item1, item2, ...)

Full source is here
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice

What's the difference between echo, print, and print_r in PHP?

echo

  • Outputs one or more strings separated by commas
  • No return value

    e.g. echo "String 1", "String 2"

print

  • Outputs only a single string
  • Returns 1, so it can be used in an expression

    e.g. print "Hello"

    or, if ($expr && print "foo")

print_r()

  • Outputs a human-readable representation of any one value
  • Accepts not just strings but other types including arrays and objects, formatting them to be readable
  • Useful when debugging
  • May return its output as a return value (instead of echoing) if the second optional argument is given

var_dump()

  • Outputs a human-readable representation of one or more values separated by commas
  • Accepts not just strings but other types including arrays and objects, formatting them to be readable
  • Uses a different output format to print_r(), for example it also prints the type of values
  • Useful when debugging
  • No return value

var_export()

  • Outputs a human-readable and PHP-executable representation of any one value
  • Accepts not just strings but other types including arrays and objects, formatting them to be readable
  • Uses a different output format to both print_r() and var_dump() - resulting output is valid PHP code!
  • Useful when debugging
  • May return its output as a return value (instead of echoing) if the second optional argument is given

Notes:

  • Even though print can be used in an expression, I recommend people avoid doing so, because it is bad for code readability (and because it's unlikely to ever be useful). The precedence rules when it interacts with other operators can also be confusing. Because of this, I personally don't ever have a reason to use it over echo.
  • Whereas echo and print are language constructs, print_r() and var_dump()/var_export() are regular functions. You don't need parentheses to enclose the arguments to echo or print (and if you do use them, they'll be treated as they would in an expression).
  • While var_export() returns valid PHP code allowing values to be read back later, relying on this for production code may make it easier to introduce security vulnerabilities due to the need to use eval(). It would be better to use a format like JSON instead to store and read back values. The speed will be comparable.

How to set a cookie for another domain

You cannot set cookies for another domain. Allowing this would present an enormous security flaw.

You need to get b.com to set the cookie. If a.com redirect the user to b.com/setcookie.php?c=value

The setcookie script could contain the following to set the cookie and redirect to the correct page on b.com

<?php
    setcookie('a', $_GET['c']);
    header("Location: b.com/landingpage.php");
?>

How to add option to select list in jQuery

Doing it this way has always worked for me, I hope this helps.

var ddl = $("#dropListBuilding");   
for (k = 0; k < buildings.length; k++)
   ddl.append("<option value='" + buildings[k]+ "'>" + buildings[k] + "</option>");

How to deep merge instead of shallow merge?

My use case for this was to merge default values into a configuration. If my component accepts a configuration object that has a deeply nested structure, and my component defines a default configuration, I wanted to set default values in my configuration for all configuration options that were not supplied.

Example usage:

export default MyComponent = ({config}) => {
  const mergedConfig = mergeDefaults(config, {header:{margins:{left:10, top: 10}}});
  // Component code here
}

This allows me to pass an empty or null config, or a partial config and have all of the values that are not configured fall back to their default values.

My implementation of mergeDefaults looks like this:

export default function mergeDefaults(config, defaults) {
  if (config === null || config === undefined) return defaults;
  for (var attrname in defaults) {
    if (defaults[attrname].constructor === Object) config[attrname] = mergeDefaults(config[attrname], defaults[attrname]);
    else if (config[attrname] === undefined) config[attrname] = defaults[attrname];
  }
  return config;
}


And these are my unit tests

import '@testing-library/jest-dom/extend-expect';
import mergeDefaults from './mergeDefaults';

describe('mergeDefaults', () => {
  it('should create configuration', () => {
    const config = mergeDefaults(null, { a: 10, b: { c: 'default1', d: 'default2' } });
    expect(config.a).toStrictEqual(10);
    expect(config.b.c).toStrictEqual('default1');
    expect(config.b.d).toStrictEqual('default2');
  });
  it('should fill configuration', () => {
    const config = mergeDefaults({}, { a: 10, b: { c: 'default1', d: 'default2' } });
    expect(config.a).toStrictEqual(10);
    expect(config.b.c).toStrictEqual('default1');
    expect(config.b.d).toStrictEqual('default2');
  });
  it('should not overwrite configuration', () => {
    const config = mergeDefaults({ a: 12, b: { c: 'config1', d: 'config2' } }, { a: 10, b: { c: 'default1', d: 'default2' } });
    expect(config.a).toStrictEqual(12);
    expect(config.b.c).toStrictEqual('config1');
    expect(config.b.d).toStrictEqual('config2');
  });
  it('should merge configuration', () => {
    const config = mergeDefaults({ a: 12, b: { d: 'config2' } }, { a: 10, b: { c: 'default1', d: 'default2' }, e: 15 });
    expect(config.a).toStrictEqual(12);
    expect(config.b.c).toStrictEqual('default1');
    expect(config.b.d).toStrictEqual('config2');
    expect(config.e).toStrictEqual(15);
  });
});

(Mac) -bash: __git_ps1: command not found

If you're hoping to use Homebrew to upgrade Git and you've let your system become out-of-date in general (as I did), you may need to bring Homebrew itself up-to-date first (as per brew update: The following untracked working tree files would be overwritten by merge: thanks @chris-frisina)

First bring Homebrew into line with the current version

cd /usr/local
git fetch origin
git reset --hard origin/master

Then update Git:

brew upgrade git

Problem Solved! ;-)

Is "delete this" allowed in C++?

The C++ FAQ Lite has a entry specifically for this

I think this quote sums it up nicely

As long as you're careful, it's OK for an object to commit suicide (delete this).

How to load a jar file at runtime

Reloading existing classes with existing data is likely to break things.

You can load new code into new class loaders relatively easily:

ClassLoader loader = URLClassLoader.newInstance(
    new URL[] { yourURL },
    getClass().getClassLoader()
);
Class<?> clazz = Class.forName("mypackage.MyClass", true, loader);
Class<? extends Runnable> runClass = clazz.asSubclass(Runnable.class);
// Avoid Class.newInstance, for it is evil.
Constructor<? extends Runnable> ctor = runClass.getConstructor();
Runnable doRun = ctor.newInstance();
doRun.run();

Class loaders no longer used can be garbage collected (unless there is a memory leak, as is often the case with using ThreadLocal, JDBC drivers, java.beans, etc).

If you want to keep the object data, then I suggest a persistence mechanism such as Serialisation, or whatever you are used to.

Of course debugging systems can do fancier things, but are more hacky and less reliable.

It is possible to add new classes into a class loader. For instance, using URLClassLoader.addURL. However, if a class fails to load (because, say, you haven't added it), then it will never load in that class loader instance.

What does from __future__ import absolute_import actually do?

The difference between absolute and relative imports come into play only when you import a module from a package and that module imports an other submodule from that package. See the difference:

$ mkdir pkg
$ touch pkg/__init__.py
$ touch pkg/string.py
$ echo 'import string;print(string.ascii_uppercase)' > pkg/main1.py
$ python2
Python 2.7.9 (default, Dec 13 2014, 18:02:08) [GCC] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pkg.main1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "pkg/main1.py", line 1, in <module>
    import string;print(string.ascii_uppercase)
AttributeError: 'module' object has no attribute 'ascii_uppercase'
>>> 
$ echo 'from __future__ import absolute_import;import string;print(string.ascii_uppercase)' > pkg/main2.py
$ python2
Python 2.7.9 (default, Dec 13 2014, 18:02:08) [GCC] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pkg.main2
ABCDEFGHIJKLMNOPQRSTUVWXYZ
>>> 

In particular:

$ python2 pkg/main2.py
Traceback (most recent call last):
  File "pkg/main2.py", line 1, in <module>
    from __future__ import absolute_import;import string;print(string.ascii_uppercase)
AttributeError: 'module' object has no attribute 'ascii_uppercase'
$ python2
Python 2.7.9 (default, Dec 13 2014, 18:02:08) [GCC] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pkg.main2
ABCDEFGHIJKLMNOPQRSTUVWXYZ
>>> 
$ python2 -m pkg.main2
ABCDEFGHIJKLMNOPQRSTUVWXYZ

Note that python2 pkg/main2.py has a different behaviour then launching python2 and then importing pkg.main2 (which is equivalent to using the -m switch).

If you ever want to run a submodule of a package always use the -m switch which prevents the interpreter for chaining the sys.path list and correctly handles the semantics of the submodule.

Also, I much prefer using explicit relative imports for package submodules since they provide more semantics and better error messages in case of failure.

virtualbox Raw-mode is unavailable courtesy of Hyper-V windows 10

In my case, was the Docker that cause problems:

enter image description here

Pandas convert string to int

You need add parameter errors='coerce' to function to_numeric:

ID = pd.to_numeric(ID, errors='coerce')

If ID is column:

df.ID = pd.to_numeric(df.ID, errors='coerce')

but non numeric are converted to NaN, so all values are float.

For int need convert NaN to some value e.g. 0 and then cast to int:

df.ID = pd.to_numeric(df.ID, errors='coerce').fillna(0).astype(np.int64)

Sample:

df = pd.DataFrame({'ID':['4806105017087','4806105017087','CN414149']})
print (df)
              ID
0  4806105017087
1  4806105017087
2       CN414149

print (pd.to_numeric(df.ID, errors='coerce'))
0    4.806105e+12
1    4.806105e+12
2             NaN
Name: ID, dtype: float64

df.ID = pd.to_numeric(df.ID, errors='coerce').fillna(0).astype(np.int64)
print (df)
              ID
0  4806105017087
1  4806105017087
2              0

EDIT: If use pandas 0.25+ then is possible use integer_na:

df.ID = pd.to_numeric(df.ID, errors='coerce').astype('Int64')
print (df)
              ID
0  4806105017087
1  4806105017087
2            NaN

sendKeys() in Selenium web driver

Try using Robot class in java for pressing TAB key. Use the below code.

driver.findElement(By.xpath("//label[text()='User Name:']/following::div/input")).sendKeys("UserName");

Robot robot = new Robot();
robot.keyPress(KeyEvent.VK_TAB);
robot.keyRelease(KeyEvent.VK_TAB);

How to import an excel file in to a MySQL database

Another useful tool, and as a MySQL front-end replacement, is Toad for MySQL. Sadly, no longer supported by Quest, but a brilliant IDE for MySQL, with IMPORT and EXPORT wizards, catering for most file types.

jQuery location href

You can use just JavaScript:

window.location = 'http://address.com';

moving committed (but not pushed) changes to a new branch after pull

  1. Checkout fresh copy of you sources

    git clone ........

  2. Make branch from desired position

    git checkout {position} git checkout -b {branch-name}

  3. Add remote repository

    git remote add shared ../{original sources location}.git

  4. Get remote sources

    git fetch shared

  5. Checkout desired branch

    git checkout {branch-name}

  6. Merge sources

    git merge shared/{original branch from shared repository}

Use find command but exclude files in two directories

You can try below:

find ./ ! \( -path ./tmp -prune \) ! \( -path ./scripts -prune \) -type f -name '*_peaks.bed'

iOS: present view controller programmatically

You need to set storyboard Id from storyboard identity inspector

 AddTaskViewController *add=[self.storyboard instantiateViewControllerWithIdentifier:@"storyboard_id"];
 [self presentViewController:add animated:YES completion:nil];

Windows Scheduled task succeeds but returns result 0x1

It seems many users are having issues with this. Here are some fixes:

  • Right click on your task > "Properties" > "Actions" > "Edit" | Put ONLY the file name under 'Program/Script', no quotes and ONLY the directory under 'Start in' as described, again no quotes.

  • Right click on your task > "Properties" > "General" | Test with any/all of the following:

    1. "Run with highest privileges" (test both options)
    2. "Run wheter user is logged on or not" (test both options)
    3. Check that "Configure for" is set to your machine's OS version
    4. Make sure the user account running the program has the right permissions

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

Had the same issue, In my case I had 1. Parse the string into Json 2. Ensure that when I render my view does not try to display the whole object, but object.value

data = [
{
    "id": 1,
    "name": "Home Page",
    "info": "This little bit of info is being loaded from a Rails 
    API.",
    "created_at": "2018-09-18T16:39:22.184Z",
    "updated_at": "2018-09-18T16:39:22.184Z"
}];
var jsonData = JSON.parse(data)

Then my view

return (
<View style={styles.container}>
  <FlatList
    data={jsonData}
    renderItem={({ item }) => <Item title={item.name} />}
    keyExtractor={item => item.id}
  />
</View>);

Because I'm using an array, I used flat list to display, and ensured I work with object.value, not object otherwise you'll get the same issue

Android: Vertical alignment for multi line EditText (Text area)

This is similar to CommonsWare answer but with a minor tweak: android:gravity="top|start". Complete code example:

<EditText
    android:id="@+id/EditText02"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:lines="5"
    android:gravity="top|start"
    android:inputType="textMultiLine"
    android:scrollHorizontally="false" 
/>

Get HTML source of WebElement in Selenium WebDriver using Python

It looks outdated, but let it be here anyway. The correct way to do it in your case:

elem = wd.find_element_by_css_selector('#my-id')
html = wd.execute_script("return arguments[0].innerHTML;", elem)

or

html = elem.get_attribute('innerHTML')

Both are working for me (selenium-server-standalone-2.35.0).

Merge data frames based on rownames in R

See ?merge:

the name "row.names" or the number 0 specifies the row names.

Example:

R> de <- merge(d, e, by=0, all=TRUE)  # merge by row names (by=0 or by="row.names")
R> de[is.na(de)] <- 0                 # replace NA values
R> de
  Row.names   a   b   c   d   e   f   g   h   i  j  k  l  m  n  o  p  q  r  s
1         1 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10 11 12 13 14 15 16 17 18 19
2         2 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9  1  0  0  0  0  0  0  0  0  0
3         3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  0 21 22 23 24 25 26 27 28 29
   t
1 20
2  0
3 30

How to determine whether a substring is in a different string

You can also try find() method. It determines if string str occurs in string, or in a substring of string.

str1 = "please help me out so that I could solve this"
str2 = "please help me out"

if (str1.find(str2)>=0):
  print("True")
else:
  print ("False")

Select rows where column is null

Do you mean something like:

SELECT COLUMN1, COLUMN2 FROM MY_TABLE WHERE COLUMN1 = 'Value' OR COLUMN1 IS NULL

?

Why is "npm install" really slow?

we also have had similar problems (we're behind a corporate proxy). changing to yarn at least on our jenkins builds made a huge difference.

there are some minor differences in the results between "npm install" and "yarn install" - but nothing that hurts us.

C# : changing listbox row color?

You will need to draw the item yourself. Change the DrawMode to OwnerDrawFixed and handle the DrawItem event.

/// <summary>
/// Handles the DrawItem event of the listBox1 control.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="System.Windows.Forms.DrawItemEventArgs"/> instance containing the event data.</param>
private void listBox1_DrawItem( object sender, DrawItemEventArgs e )
{
   e.DrawBackground();
   Graphics g = e.Graphics;

    // draw the background color you want
    // mine is set to olive, change it to whatever you want
    g.FillRectangle( new SolidBrush( Color.Olive), e.Bounds );

    // draw the text of the list item, not doing this will only show
    // the background color
    // you will need to get the text of item to display
    g.DrawString( THE_LIST_ITEM_TEXT , e.Font, new SolidBrush( e.ForeColor ), new PointF( e.Bounds.X, e.Bounds.Y) );

    e.DrawFocusRectangle();
}

updating nodejs on ubuntu 16.04

According to official docs to install node on Debian and Ubuntu based distributions:

node v12 (Old)

curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -
sudo apt-get install -y nodejs

node v14 (For new users: install this one):

curl -sL https://deb.nodesource.com/setup_14.x | sudo -E bash -
sudo apt-get install -y nodejs

node v15 (Current version):

curl -sL https://deb.nodesource.com/setup_15.x | sudo -E bash -
sudo apt-get install -y nodejs

Other older versions: Just replace the desired version number in the link above.

Optional: install build tools

To compile and install native packages

sudo apt-get install -y build-essential

To update node to the latest version just:

sudo apt update
sudo apt upgrade

To keep npm updated

sudo npm i -g npm

To find out other versions try npm info npm and in versions find your desired version and replace [version-tag] with that version tag in npm i -g npm@[version-tag]

And I also recommend trying yarn instead of npm

Unable to open debugger port in IntelliJ

  1. In glassfish\domains\domain1\config\domain.xml set before start server:

_x000D_
_x000D_
      <java-config classpath-suffix="" debug-options="-agentlib:jdwp=transport=dt_socket,address=9009,server=y,suspend=n" java-home="C:\Program Files\Java\jdk1.8.0_162" debug-enabled="true" system-classpath="">
_x000D_
_x000D_
_x000D_

or set debug-enabled="true" server=y,suspend=n in http://localhost:4848/common/index.jsf Glassfish 4 address=9009,server=y,suspend=n

  1. In current Idea 2018 - Server Run Configuration - Debug - Port - address Server Run Configuration - Debug - Port - address

True/False vs 0/1 in MySQL

Some "front ends", with the "Use Booleans" option enabled, will treat all TINYINT(1) columns as Boolean, and vice versa.

This allows you to, in the application, use TRUE and FALSE rather than 1 and 0.

This doesn't affect the database at all, since it's implemented in the application.

There is not really a BOOLEAN type in MySQL. BOOLEAN is just a synonym for TINYINT(1), and TRUE and FALSE are synonyms for 1 and 0.

If the conversion is done in the compiler, there will be no difference in performance in the application. Otherwise, the difference still won't be noticeable.

You should use whichever method allows you to code more efficiently, though not using the feature may reduce dependency on that particular "front end" vendor.

How to add a delay for a 2 or 3 seconds

Use a timer with an interval set to 2–3 seconds.

You have three different options to choose from, depending on which type of application you're writing:

  1. System.Timers.Timer
  2. System.Windows.Forms.Timer
  3. System.Threading.Timer

Don't use Thread.Sleep if your application need to process any inputs on that thread at the same time (WinForms, WPF), as Sleep will completely lock up the thread and prevent it from processing other messages. Assuming a single-threaded application (as most are), your entire application will stop responding, rather than just delaying an operation as you probably intended. Note that it may be fine to use Sleep in pure console application as there are no "events" to handle or on separate thread (also Task.Delay is better option).

In addition to timers and Sleep you can use Task.Delay which is asynchronous version of Sleep that does not block thread from processing events (if used properly - don't turn it into infinite sleep with .Wait()).

 public async void ClickHandler(...)
 {
      // whatever you need to do before delay goes here         

      await Task.Delay(2000);

      // whatever you need to do after delay.
 }

The same await Task.Delay(2000) can be used in a Main method of a console application if you use C# 7.1 (Async main on MSDN blogs).

Note: delaying operation with Sleep has benefit of avoiding race conditions that comes from potentially starting multiple operations with timers/Delay. Unfortunately freezing UI-based application is not acceptable so you need to think about what will happen if you start multiple delays (i.e. if it is triggered by a button click) - consider disabling such button, or canceling the timer/task or making sure delayed operation can be done multiple times safely.

How to use jQuery with Angular?

Just write

declare var $:any;

after all import sections, you can use jQuery and include the jQuery library in your index.html page

<script src="https://code.jquery.com/jquery-3.3.1.js"></script>

it worked for me

Get JSON object from URL

my solution only works for the next cases: if you are mistaking a multidimensaional array into a single one

$json = file_get_contents('url_json'); //get the json
$objhigher=json_decode($json); //converts to an object
$objlower = $objhigher[0]; // if the json response its multidimensional this lowers it
echo "<pre>"; //box for code
print_r($objlower); //prints the object with all key and values
echo $objlower->access_token; //prints the variable

i know that the answer was has already been answered but for those who came here looking for something i hope this can help you

How to force a SQL Server 2008 database to go Offline

You need to use WITH ROLLBACK IMMEDIATE to boot other conections out with no regards to what or who is is already using it.

Or use WITH NO_WAIT to not hang and not kill existing connections. See http://www.blackwasp.co.uk/SQLOffline.aspx for details

How to assign from a function which returns more than one value?

Yes to your second and third questions -- that's what you need to do as you cannot have multiple 'lvalues' on the left of an assignment.

How can I make an EXE file from a Python program?

Use cx_Freeze to make exe your python program

How to commit changes to a new branch

If you haven't committed changes

If your changes are compatible with the other branch

This is the case from the question because the OP wants to commit to a new branch and also applies if your changes are compatible with the target branch without triggering an overwrite.

As in the accepted answer by John Brodie, you can simply checkout the new branch and commit the work:

git checkout -b branch_name
git add <files>
git commit -m "message"

If your changes are incompatible with the other branch

If you get the error:

error: Your local changes to the following files would be overwritten by checkout:
...
Please commit your changes or stash them before you switch branches

Then you can stash your work, create a new branch, then pop your stash changes, and resolve the conflicts:

git stash
git checkout -b branch_name
git stash pop

It will be as if you had made those changes after creating the new branch. Then you can commit as usual:

git add <files>
git commit -m "message"

If you have committed changes

If you want to keep the commits in the original branch

See the answer by Carl Norum with cherry-picking, which is the right tool in this case:

git checkout <target name>
git cherry-pick <original branch>

If you don't want to keep the commits in the original branch

See the answer by joeytwiddle on this potential duplicate. Follow any of the above steps as appropriate, then roll back the original branch:

git branch -f <original branch> <earlier commit id>

If you have pushed your changes to a shared remote like GitHub, you should not attempt this roll-back unless you know what you are doing.

Full width image with fixed height

#image {
  width: 100%;
  height: 100px; //static
  object-fit: cover;
}

How to check if a string is a number?

rewrite the whole function as below:

bool IsValidNumber(char * string)
{
   for(int i = 0; i < strlen( string ); i ++)
   {
      //ASCII value of 0 = 48, 9 = 57. So if value is outside of numeric range then fail
      //Checking for negative sign "-" could be added: ASCII value 45.
      if (string[i] < 48 || string[i] > 57)
         return FALSE;
   }

   return TRUE;
}

How to clone an InputStream?

If all you want to do is read the same information more than once, and the input data is small enough to fit into memory, you can copy the data from your InputStream to a ByteArrayOutputStream.

Then you can obtain the associated array of bytes and open as many "cloned" ByteArrayInputStreams as you like.

ByteArrayOutputStream baos = new ByteArrayOutputStream();

// Code simulating the copy
// You could alternatively use NIO
// And please, unlike me, do something about the Exceptions :D
byte[] buffer = new byte[1024];
int len;
while ((len = input.read(buffer)) > -1 ) {
    baos.write(buffer, 0, len);
}
baos.flush();
    
// Open new InputStreams using recorded bytes
// Can be repeated as many times as you wish
InputStream is1 = new ByteArrayInputStream(baos.toByteArray()); 
InputStream is2 = new ByteArrayInputStream(baos.toByteArray()); 

But if you really need to keep the original stream open to receive new data, then you will need to track the external call to close(). You will need to prevent close() from being called somehow.

UPDATE (2019):

Since Java 9 the the middle bits can be replaced with InputStream.transferTo:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
input.transferTo(baos);
InputStream firstClone = new ByteArrayInputStream(baos.toByteArray()); 
InputStream secondClone = new ByteArrayInputStream(baos.toByteArray()); 

How to handle screen orientation change when progress dialog and background thread active?

The original perceived problem was that the code would not survive a screen orientation change. Apparently this was "solved" by having the program handle the screen orientation change itself, instead of letting the UI framework do it (via calling onDestroy)).

I would submit that if the underlying problem is that the program will not survive onDestroy(), then the accepted solution is just a workaround that leaves the program with serious other problems and vulnerabilities. Remember that the Android framework specifically states that your activity is at risk for being destroyed almost at any time due to circumstances outside your control. Therefore, your activity must be able to survive onDestroy() and subsequent onCreate() for any reason, not just a screen orientation change.

If you are going to accept handling screen orientation changes yourself to solve the OP's problem, you need to verify that other causes of onDestroy() do not result in the same error. Are you able to do this? If not, I would question whether the "accepted" answer is really a very good one.

How to generate unique IDs for form labels in React?

Hopefully this is helpful to anyone coming looking for a universal/isomorphic solution, since the checksum issue is what led me here in the first place.

As said above, I've created a simple utility to sequentially create a new id. Since the IDs keep incrementing on the server, and start over from 0 in the client, I decided to reset the increment each the SSR starts.

// utility to generate ids
let current = 0

export default function generateId (prefix) {
  return `${prefix || 'id'}-${current++}`
}

export function resetIdCounter () { current = 0 }

And then in the root component's constructor or componentWillMount, call the reset. This essentially resets the JS scope for the server in each server render. In the client it doesn't (and shouldn't) have any effect.

How to get number of entries in a Lua table?

local function CountedTable(x)
    assert(type(x) == 'table', 'bad parameter #1: must be table')

    local new_t = {}
    local mt = {}

    -- `all` will represent the number of both
    local all = 0
    for k, v in pairs(x) do
        all = all + 1
    end

    mt.__newindex = function(t, k, v)
        if v == nil then
            if rawget(x, k) ~= nil then
                all = all - 1
            end
        else
            if rawget(x, k) == nil then
                all = all + 1
            end
        end

        rawset(x, k, v)
    end

    mt.__index = function(t, k)
        if k == 'totalCount' then return all
        else return rawget(x, k) end
    end

    return setmetatable(new_t, mt)
end

local bar = CountedTable { x = 23, y = 43, z = 334, [true] = true }

assert(bar.totalCount == 4)
assert(bar.x == 23)
bar.x = nil
assert(bar.totalCount == 3)
bar.x = nil
assert(bar.totalCount == 3)
bar.x = 24
bar.x = 25
assert(bar.x == 25)
assert(bar.totalCount == 4)

Image comparison - fast algorithm

Below are three approaches to solving this problem (and there are many others).

  • The first is a standard approach in computer vision, keypoint matching. This may require some background knowledge to implement, and can be slow.

  • The second method uses only elementary image processing, and is potentially faster than the first approach, and is straightforward to implement. However, what it gains in understandability, it lacks in robustness -- matching fails on scaled, rotated, or discolored images.

  • The third method is both fast and robust, but is potentially the hardest to implement.

Keypoint Matching

Better than picking 100 random points is picking 100 important points. Certain parts of an image have more information than others (particularly at edges and corners), and these are the ones you'll want to use for smart image matching. Google "keypoint extraction" and "keypoint matching" and you'll find quite a few academic papers on the subject. These days, SIFT keypoints are arguably the most popular, since they can match images under different scales, rotations, and lighting. Some SIFT implementations can be found here.

One downside to keypoint matching is the running time of a naive implementation: O(n^2m), where n is the number of keypoints in each image, and m is the number of images in the database. Some clever algorithms might find the closest match faster, like quadtrees or binary space partitioning.


Alternative solution: Histogram method

Another less robust but potentially faster solution is to build feature histograms for each image, and choose the image with the histogram closest to the input image's histogram. I implemented this as an undergrad, and we used 3 color histograms (red, green, and blue), and two texture histograms, direction and scale. I'll give the details below, but I should note that this only worked well for matching images VERY similar to the database images. Re-scaled, rotated, or discolored images can fail with this method, but small changes like cropping won't break the algorithm

Computing the color histograms is straightforward -- just pick the range for your histogram buckets, and for each range, tally the number of pixels with a color in that range. For example, consider the "green" histogram, and suppose we choose 4 buckets for our histogram: 0-63, 64-127, 128-191, and 192-255. Then for each pixel, we look at the green value, and add a tally to the appropriate bucket. When we're done tallying, we divide each bucket total by the number of pixels in the entire image to get a normalized histogram for the green channel.

For the texture direction histogram, we started by performing edge detection on the image. Each edge point has a normal vector pointing in the direction perpendicular to the edge. We quantized the normal vector's angle into one of 6 buckets between 0 and PI (since edges have 180-degree symmetry, we converted angles between -PI and 0 to be between 0 and PI). After tallying up the number of edge points in each direction, we have an un-normalized histogram representing texture direction, which we normalized by dividing each bucket by the total number of edge points in the image.

To compute the texture scale histogram, for each edge point, we measured the distance to the next-closest edge point with the same direction. For example, if edge point A has a direction of 45 degrees, the algorithm walks in that direction until it finds another edge point with a direction of 45 degrees (or within a reasonable deviation). After computing this distance for each edge point, we dump those values into a histogram and normalize it by dividing by the total number of edge points.

Now you have 5 histograms for each image. To compare two images, you take the absolute value of the difference between each histogram bucket, and then sum these values. For example, to compare images A and B, we would compute

|A.green_histogram.bucket_1 - B.green_histogram.bucket_1| 

for each bucket in the green histogram, and repeat for the other histograms, and then sum up all the results. The smaller the result, the better the match. Repeat for all images in the database, and the match with the smallest result wins. You'd probably want to have a threshold, above which the algorithm concludes that no match was found.


Third Choice - Keypoints + Decision Trees

A third approach that is probably much faster than the other two is using semantic texton forests (PDF). This involves extracting simple keypoints and using a collection decision trees to classify the image. This is faster than simple SIFT keypoint matching, because it avoids the costly matching process, and keypoints are much simpler than SIFT, so keypoint extraction is much faster. However, it preserves the SIFT method's invariance to rotation, scale, and lighting, an important feature that the histogram method lacked.

Update:

My mistake -- the Semantic Texton Forests paper isn't specifically about image matching, but rather region labeling. The original paper that does matching is this one: Keypoint Recognition using Randomized Trees. Also, the papers below continue to develop the ideas and represent the state of the art (c. 2010):

What is the difference between __init__ and __call__?

So, __init__ is called when you are creating an instance of any class and initializing the instance variable also.

Example:

class User:

    def __init__(self,first_n,last_n,age):
        self.first_n = first_n
        self.last_n = last_n
        self.age = age

user1 = User("Jhone","Wrick","40")

And __call__ is called when you call the object like any other function.

Example:

class USER:
    def __call__(self,arg):
        "todo here"
         print(f"I am in __call__ with arg : {arg} ")


user1=USER()
user1("One") #calling the object user1 and that's gonna call __call__ dunder functions

How can I use querySelector on to pick an input element by name?

querySelector() matched the id in document. You must write id of password in .html

Then pass it to querySelector() with #symbol & .value property.

Example:

let myVal = document.querySelector('#pwd').value

What do Clustered and Non clustered index actually mean?

Clustered Index

Clustered indexes sort and store the data rows in the table or view based on their key values. These are the columns included in the index definition. There can be only one clustered index per table, because the data rows themselves can be sorted in only one order.

The only time the data rows in a table are stored in sorted order is when the table contains a clustered index. When a table has a clustered index, the table is called a clustered table. If a table has no clustered index, its data rows are stored in an unordered structure called a heap.

Nonclustered

Nonclustered indexes have a structure separate from the data rows. A nonclustered index contains the nonclustered index key values and each key value entry has a pointer to the data row that contains the key value. The pointer from an index row in a nonclustered index to a data row is called a row locator. The structure of the row locator depends on whether the data pages are stored in a heap or a clustered table. For a heap, a row locator is a pointer to the row. For a clustered table, the row locator is the clustered index key.

You can add nonkey columns to the leaf level of the nonclustered index to by-pass existing index key limits, and execute fully covered, indexed, queries. For more information, see Create Indexes with Included Columns. For details about index key limits see Maximum Capacity Specifications for SQL Server.

Reference: https://docs.microsoft.com/en-us/sql/relational-databases/indexes/clustered-and-nonclustered-indexes-described

WPF Databinding: How do I access the "parent" data context?

You could try something like this:

...Binding="{Binding RelativeSource={RelativeSource FindAncestor, 
AncestorType={x:Type Window}}, Path=DataContext.AllowItemCommand}" ...

Reversing a string in C

This complete program shows how I would do it. Keep in mind I was writing C when most of you whippersnappers were a glint in your mothers eyes so it's old-school, do-the-job, long-var-names-are-for-wimps. Fix that if you wish, I'm more interested in the correctness of the code.

It handles NULLs, empty strings and all string sizes. I haven't tested it with strings of maximum size (max(size_t)) but it should work, and if you're handling strings that big, you're insane anyway :-)

#include <stdio.h>
#include <string.h>

char *revStr (char *str) {
    char tmp, *src, *dst;
    size_t len;
    if (str != NULL)
    {
        len = strlen (str);
        if (len > 1) {
            src = str;
            dst = src + len - 1;
            while (src < dst) {
                tmp = *src;
                *src++ = *dst;
                *dst-- = tmp;
            }
        }
    }
    return str;
}

char *str[] = {"", "a", "ab", "abc", "abcd", "abcde"};

int main(int argc, char *argv[]) {
    int i;
    char s[10000];
    for (i=0; i < sizeof(str)/sizeof(str[0]); i++) {
        strcpy (s, str[i]);
        printf ("'%s' -> '%s'\n", str[i], revStr(s));
    }
    return 0;
}

The output of that is:

'' -> ''
'a' -> 'a'
'ab' -> 'ba'
'abc' -> 'cba'
'abcd' -> 'dcba'
'abcde' -> 'edcba'

How to change font of UIButton with Swift

Example: button.titleLabel?.font = UIFont(name: "HelveticaNeue-Bold", size: 12)

  • If you want to use defaul font from it's own family, use for example: "HelveticaNeue"
  • If you want to specify family font, use for example: "HelveticaNeue-Bold"

How do I use the nohup command without getting nohup.out?

Have you tried redirecting all three I/O streams:

nohup ./yourprogram > foo.out 2> foo.err < /dev/null &

How do I see if Wi-Fi is connected on Android?

You should be able to use the ConnectivityManager to get the state of the Wi-Fi adapter. From there you can check if it is connected or even available.

ConnectivityManager connManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mWifi = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);

if (mWifi.isConnected()) {
    // Do whatever
}

NOTE: It should be noted (for us n00bies here) that you need to add

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

to your

AndroidManifest.xml for this to work.

NOTE2: public NetworkInfo getNetworkInfo (int networkType) is now deprecated:

This method was deprecated in API level 23. This method does not support multiple connected networks of the same type. Use getAllNetworks() and getNetworkInfo(android.net.Network) instead.

NOTE3: public static final int TYPE_WIFI is now deprecated:

This constant was deprecated in API level 28. Applications should instead use NetworkCapabilities.hasTransport(int) or requestNetwork(NetworkRequest, NetworkCallback) to request an appropriate network. for supported transports.

How to get "GET" request parameters in JavaScript?

try the below code, it will help you get the GET parameters from url . for more details.

 var url_string = window.location.href; // www.test.com?filename=test
    var url = new URL(url_string);
    var paramValue = url.searchParams.get("filename");
    alert(paramValue)

How do I use cascade delete with SQL Server?

Use something like

ALTER TABLE T2
ADD CONSTRAINT fk_employee
FOREIGN KEY (employeeID)
REFERENCES T1 (employeeID)
ON DELETE CASCADE;

Fill in the correct column names and you should be set. As mark_s correctly stated, if you have already a foreign key constraint in place, you maybe need to delete the old one first and then create the new one.

Android difference between Two Dates

I use this: send start and end date in millisecond

public int GetDifference(long start,long end){
    Calendar cal = Calendar.getInstance();
    cal.setTimeInMillis(start);
    int hour = cal.get(Calendar.HOUR_OF_DAY);
    int min = cal.get(Calendar.MINUTE);
    long t=(23-hour)*3600000+(59-min)*60000;

    t=start+t;

    int diff=0;
    if(end>t){
        diff=(int)((end-t)/ TimeUnit.DAYS.toMillis(1))+1;
    }

    return  diff;
}

Where does the slf4j log file get saved?

slf4j is only an API. You should have a concrete implementation (for example log4j). This concrete implementation has a config file which tells you where to store the logs.

enter image description here

When slf4j catches a log messages with a logger, it is given to an appender which decides what to do with the message. By default, the ConsoleAppender displays the message in the console.

The default configuration file is :

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">

  <Appenders>
    <!-- By default => console -->
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
    </Console>
  </Appenders>

  <Loggers>
    <Root level="error">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

If you put a configuration file available in the classpath, then your concrete implementation (in your case, log4j) will find and use it. See Log4J documentation.

Example of file appender :

<Appenders>
<File name="File" fileName="${filename}">
  <PatternLayout>
    <pattern>%d %p %C{1.} [%t] %m%n</pattern>
  </PatternLayout>
</File>

...
</Appenders>

Complete example with a file appender :

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">

  <Appenders>
    <File name="File" fileName="${filename}">
      <PatternLayout>
        <pattern>%d %p %C{1.} [%t] %m%n</pattern>
      </PatternLayout>
    </File>
  </Appenders>

  <Loggers>
    <Root level="error">
      <AppenderRef ref="File"/>
    </Root>
  </Loggers>

</Configuration>

How do I prevent a parent's onclick event from firing when a child anchor is clicked?

ignoreParent() is a pure JavaScript solution.

It works as an intermediary layer that compares the coordinates of the mouse click with the coordinates of the child element/s. Two simple implementation steps:

1. Put the ignoreParent() code on your page.

2. Instead of the parent's original onclick="parentEvent();", write:

onclick="ignoreParent(['parentEvent()', 'child-ID']);"

You may pass IDs of any number of child elements to the function, and exclude others.

If you clicked on one of the child elements, the parent event doesn't fire. If you clicked on parent, but not on any of the child elements [provided as arguments], the parent event is fired.

ignoreParent() code on Github

Get cookie by name

Just use the following function (a pure javascript code)

const getCookie = (name) => {
 const cookies = Object.assign({}, ...document.cookie.split('; ').map(cookie => {
    const name = cookie.split('=')[0];
    const value = cookie.split('=')[1];

    return {[name]: value};
  }));

  return cookies[name];
};

Calling a function when ng-repeat has finished

I'm very surprised not to see the most simple solution among the answers to this question. What you want to do is add an ngInit directive on your repeated element (the element with the ngRepeat directive) checking for $last (a special variable set in scope by ngRepeat which indicates that the repeated element is the last in the list). If $last is true, we're rendering the last element and we can call the function we want.

ng-init="$last && test()"

The complete code for your HTML markup would be:

<div ng-app="testApp" ng-controller="myC">
    <p ng-repeat="t in ta" ng-init="$last && test()">{{t}}</p>
</div>

You don't need any extra JS code in your app besides the scope function you want to call (in this case, test) since ngInit is provided by Angular.js. Just make sure to have your test function in the scope so that it can be accessed from the template:

$scope.test = function test() {
    console.log("test executed");
}

How to check whether input value is integer or float?

You can use RoundingMode.#UNNECESSARY if you want/accept exception thrown otherwise

new BigDecimal(value).setScale(2, RoundingMode.UNNECESSARY);

If this rounding mode is specified on an operation that yields an inexact result, an ArithmeticException is thrown.

Exception if not integer value:

java.lang.ArithmeticException: Rounding necessary

Check if image exists on server using JavaScript?

This works fine:

function checkImage(imageSrc) {
    var img = new Image();        
    try {
        img.src = imageSrc;
        return true;
    } catch(err) {
        return false;
    }    
}

No Persistence provider for EntityManager named

Quick advice:

  • check if persistence.xml is in your classpath
  • check if hibernate provider is in your classpath

With using JPA in standalone application (outside of JavaEE), a persistence provider needs to be specified somewhere. This can be done in two ways that I know of:

In my case, I found out that due to maven misconfiguration, hibernate-entitymanager jar was not included as a dependency, even if it was a transient dependency of other module.

Ifelse statement in R with multiple conditions

another solution using dplyr is:

df <- ## your data ##
df <- df %>%
        mutate(Den = ifelse(any(is.na(Den)) | any(Den != 1), 0, 1))

Expected corresponding JSX closing tag for input Reactjs

This error also happens if you have got the order of your components wrong.

Example: this wrong:

 <ComponentA> 
    <ComponentB> 

    </ComponentA> 
 </ComponentB> 

correct way:

  <ComponentA> 
    <ComponentB>

    </ComponentB>  
  </ComponentA> 

javascript date + 7 days

_x000D_
_x000D_
var future = new Date(); // get today date_x000D_
future.setDate(future.getDate() + 7); // add 7 days_x000D_
var finalDate = future.getFullYear() +'-'+ ((future.getMonth() + 1) < 10 ? '0' : '') + (future.getMonth() + 1) +'-'+ future.getDate();_x000D_
console.log(finalDate);
_x000D_
_x000D_
_x000D_

How to remove unused imports from Eclipse

Remove all unused import in eclipse:

Right click on the desired package then Source->Organize Imports. Or You can direct use the shortcut by pressing Ctrl+Shift+O

Work perfectly.

How to count rows with SELECT COUNT(*) with SQLAlchemy?

Query for just a single known column:

session.query(MyTable.col1).count()

CSS transition fade on hover

I recommend you to use an unordered list for your image gallery.

You should use my code unless you want the image to gain instantly 50% opacity after you hover out. You will have a smoother transition.

#photos li {
    opacity: .5;
    transition: opacity .5s ease-out;
    -moz-transition: opacity .5s ease-out;
    -webkit-transition: opacity .5s ease-out;
    -o-transition: opacity .5s ease-out;
}

#photos li:hover {
    opacity: 1;
}

Dynamically changing font size of UILabel

Swift version:

textLabel.adjustsFontSizeToFitWidth = true
textLabel.minimumScaleFactor = 0.5

How to remove outliers in boxplot in R?

See ?boxplot for all the help you need.

 outline: if ‘outline’ is not true, the outliers are not drawn (as
          points whereas S+ uses lines).

boxplot(x,horizontal=TRUE,axes=FALSE,outline=FALSE)

And for extending the range of the whiskers and suppressing the outliers inside this range:

   range: this determines how far the plot whiskers extend out from the
          box.  If ‘range’ is positive, the whiskers extend to the most
          extreme data point which is no more than ‘range’ times the
          interquartile range from the box. A value of zero causes the
          whiskers to extend to the data extremes.

# change the value of range to change the whisker length
boxplot(x,horizontal=TRUE,axes=FALSE,range=2)

jQuery - Disable Form Fields

<script type="text/javascript" src="jquery.js"></script>          
<script type="text/javascript">
  $(document).ready(function() {
      $("#suburb").blur(function() {
          if ($(this).val() != '')
              $("#post_code").attr("disabled", "disabled");
          else
              $("#post_code").removeAttr("disabled");
      });

      $("#post_code").blur(function() {
          if ($(this).val() != '')
              $("#suburb").attr("disabled", "disabled");
          else
              $("#suburb").removeAttr("disabled");
      });
  });
</script>

You'll also need to add a value attribute to the first option under your select element:

<option value=""></option>

Pandas: create two new columns in a dataframe with values calculated from a pre-existing column

I'd just use zip:

In [1]: from pandas import *

In [2]: def calculate(x):
   ...:     return x*2, x*3
   ...: 

In [3]: df = DataFrame({'a': [1,2,3], 'b': [2,3,4]})

In [4]: df
Out[4]: 
   a  b
0  1  2
1  2  3
2  3  4

In [5]: df["A1"], df["A2"] = zip(*df["a"].map(calculate))

In [6]: df
Out[6]: 
   a  b  A1  A2
0  1  2   2   3
1  2  3   4   6
2  3  4   6   9

SQL Server Express CREATE DATABASE permission denied in database 'master'

For SQL server 2012,

  1. First, log in to the SQL server as an administrator and go to Security tab

  2. Then move into Server Roles and double click on sysadmin role

  3. Now add user which you want to give permission to create Database by clicking Add button

  4. Click OK button and now run the query

Hope this will help for someone

Export html table data to Excel using JavaScript / JQuery is not working properly in chrome browser

Regarding to sampopes answer from Jun 6 '14 at 11:59:

I have insert a css style with font-size of 20px to display the excel data greater. In sampopes code the leading <tr> tags are missing, so i first output the headline and than the other tables lines within a loop.

function fnExcelReport()
{
    var tab_text = '<table border="1px" style="font-size:20px" ">';
    var textRange; 
    var j = 0;
    var tab = document.getElementById('DataTableId'); // id of table
    var lines = tab.rows.length;

    // the first headline of the table
    if (lines > 0) {
        tab_text = tab_text + '<tr bgcolor="#DFDFDF">' + tab.rows[0].innerHTML + '</tr>';
    }

    // table data lines, loop starting from 1
    for (j = 1 ; j < lines; j++) {     
        tab_text = tab_text + "<tr>" + tab.rows[j].innerHTML + "</tr>";
    }

    tab_text = tab_text + "</table>";
    tab_text = tab_text.replace(/<A[^>]*>|<\/A>/g, "");             //remove if u want links in your table
    tab_text = tab_text.replace(/<img[^>]*>/gi,"");                 // remove if u want images in your table
    tab_text = tab_text.replace(/<input[^>]*>|<\/input>/gi, "");    // reomves input params
    // console.log(tab_text); // aktivate so see the result (press F12 in browser)

    var ua = window.navigator.userAgent;
    var msie = ua.indexOf("MSIE "); 

     // if Internet Explorer
    if (msie > 0 || !!navigator.userAgent.match(/Trident.*rv\:11\./)) {
        txtArea1.document.open("txt/html","replace");
        txtArea1.document.write(tab_text);
        txtArea1.document.close();
        txtArea1.focus(); 
        sa = txtArea1.document.execCommand("SaveAs", true, "DataTableExport.xls");
    }  
    else // other browser not tested on IE 11
        sa = window.open('data:application/vnd.ms-excel,' + encodeURIComponent(tab_text));  

    return (sa);
}   

Can't find/install libXtst.so.6?

This worked for me in Luna elementary OS

sudo apt-get install libxtst6:i386

This Activity already has an action bar supplied by the window decor

This is how I solved the problem. Add below code in your AndroidMainfest.xml

<activity android:name=".YourClass"
            android:theme="@style/Theme.AppCompat.Light.NoActionBar">
 </activity>

Read/write to file using jQuery

You will need to handle your file access through web programming language, such as PHP or ASP.net.

To set this up, you would:

  • Create a script that handles the file reading and writing. This should be visible to the browser.

  • Send jQuery ajax requests to that script that either write data or read data. You would need to pass all of your read/write information through the request parameters. You can learn more about this in the jQuery ajax documentation.

Make sure that you sanitize any data that you are storing, since this could potentially be a security risk. However, this is really just standard flat-file data storage, and is not necessarily that unusual.

As Paolo pointed out, there is no way to directly read/write to a file through jQuery or any other type of javascript.

'Access-Control-Allow-Origin' issue when API call made from React (Isomorphic app)

I had the same problem. the other answers are correct but there is another solution. you can set response header to allow cross-origin access. according to this post you have to add the following codes before any app.get call:

app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "X-Requested-With");
  next();
  });

this worked for me :)

How do I check if a string contains another string in Swift?

You don't need to write any custom code for this. Starting from the 1.2 version Swift has already had all the methods you need:

  • getting string length: count(string);
  • checking if string contains substring: contains(string, substring);
  • checking if string starts with substring: startsWith(string, substring)
  • and etc.

How to remove first 10 characters from a string?

Substring is probably what you want, as others pointed out. But just to add another option to the mix...

string result = string.Join(string.Empty, str.Skip(10));

You dont even need to check the length on this! :) If its less than 10 chars, you get an empty string.

How to create a readonly textbox in ASP.NET MVC3 Razor

With credits to the previous answer by @Bronek and @Shimmy:

This is like I have done the same thing in ASP.NET Core:

<input asp-for="DisabledField" disabled="disabled" />
<input asp-for="DisabledField" class="hidden" />

The first input is readonly and the second one passes the value to the controller and is hidden. I hope it will be useful for someone working with ASP.NET Core.

Oracle - Insert New Row with Auto Incremental ID

For completeness, I'll mention that Oracle 12c does support this feature. Also it's supposedly faster than the triggers approach. For example:

CREATE TABLE foo
  (
    id NUMBER GENERATED BY DEFAULT AS IDENTITY (
    START WITH 1 NOCACHE ORDER ) NOT NULL ,
    name       VARCHAR2 (50)
  )
  LOGGING ;
ALTER TABLE foo ADD CONSTRAINT foo_PK PRIMARY KEY ( id ) ;

Ansible playbook shell output

Expanding on what leucos said in his answer, you can also print information with Ansible's humble debug module:

- hosts: all
  gather_facts: no
  tasks:
    - shell: ps -eo pcpu,user,args | sort -r -k1 | head -n5
      register: ps

    # Print the shell task's stdout.
    - debug: msg={{ ps.stdout }}

    # Print all contents of the shell task's output.
    - debug: var=ps

How to bring back "Browser mode" in IE11?

[UPDATE]

The original question, and the answer below applied specifically to the IE11 preview releases.

The final release version of IE11 does in fact provide the ability to switch browser modes from the Emulation tab in the dev tools:

Screenshot showing browser mode selection in the emulation tab

Having said that, the advice I've given here (and elsewhere) to avoid using compatibility modes for testing is still valid: If you want to test your site for compatibility with older IE versions, you should always do your testing in a real copy of those IE version.

However, this does mean that the registry hack described in @EugeneXa's answer to bring back the old dev tools is no longer necessary, since the new dev tools do now have the feature he was missing.


[ORIGINAL ANSWER]

The IE devs have deliberately deprecated the ability to switch browser mode.

There are not many reasons why people would be switching modes in the dev tools, but one of the main reasons is because they want to test their site in old IE versions. Unfortunately, the various compatibility modes that IE supplies have never really been fully compatible with old versions of IE, and testing using compat mode is simply not a good enough substitute for testing in real copies of IE8, IE9, etc.

The IE devs have recognised this and are deliberately making it harder for devs to make this mistake.

The best practice is to use real copies of each IE version to test your site instead.

The various compatiblity modes are still available inside IE11, but can only be accessed if a site explicitly states that it wants to run in compat mode. You would do this by including an X-UA-Compatible header on your page.

And the Document Mode drop-box is still available, but will only ever offer the options of "Edge" (that is, the best mode available to the current IE version, so IE11 mode in IE11) or the mode that the page is running in.

So if you go to a page that is loaded in compat mode, you will have the option to switch between the specific compat mode that the page was loaded in or IE11 "Edge" mode.

And if you go to a page that loads in IE11 mode, then you will only be offered the 'edge' mode and nothing else.

This means that it does still allow you to test how a compat mode page reacts to being updated to work in Edge mode, which is about the only really legitimate use-case for the document mode drop-box anyway.

The IE11 Document Mode drop box has an i icon next to it which takes you to the modern.ie website. The point of this is to encourage you to download the VMs that MS are supplying for us to test our sites using real copies of each version of IE. This will give you a much more accurate testing experience, and is strongly enouraged as a much better practice than testing by switching the mode in dev tools.

Hope that explains things a bit for you.

Bootstrap 4 - Inline List?

.list-inline class in bootstrap is a Inline Unordered List.

If you want to create a horizontal menu using ordered or unordered list you need to place all list items in a single line i.e. side by side. You can do this by simply applying the class

<div class="list-inline">
    <a href="#" class="list-inline-item">First item</a>
    <a href="#" class="list-inline-item">Secound item</a>
    <a href="#" class="list-inline-item">Third item</a>
  </div>

Socket.IO - how do I get a list of connected sockets/clients?

In Socket.IO 1.4

To get the array of All connected Users :

var allConnectedClients = Object.keys(io.sockets.connected);// This will return the array of SockeId of all the connected clients

To get the Count of all clients :

var clientsCount = io.engine.clientsCount ; // This will return the count of connected clients

Why is my Spring @Autowired field null?

I once encountered the same issue when I was not quite used to the life in the IoC world. The @Autowired field of one of my beans is null at runtime.

The root cause is, instead of using the auto-created bean maintained by the Spring IoC container (whose @Autowired field is indeed properly injected), I am newing my own instance of that bean type and using it. Of course this one's @Autowired field is null because Spring has no chance to inject it.