Programs & Examples On #Gemspecs

How to list the files inside a JAR file?

Just a different way of listing/reading files from a jar URL and it does it recursively for nested jars

https://gist.github.com/trung/2cd90faab7f75b3bcbaa

URL urlResource = Thead.currentThread().getContextClassLoader().getResource("foo");
JarReader.read(urlResource, new InputStreamCallback() {
    @Override
    public void onFile(String name, InputStream is) throws IOException {
        // got file name and content stream 
    }
});

Drop all data in a pandas dataframe

Overwrite the dataframe with something like that

import pandas as pd

df = pd.DataFrame(None)

or if you want to keep columns in place

df = pd.DataFrame(columns=df.columns)

Get line number while using grep

Line numbers are printed with grep -n:

grep -n pattern file.txt

To get only the line number (without the matching line), one may use cut:

grep -n pattern file.txt | cut -d : -f 1

Lines not containing a pattern are printed with grep -v:

grep -v pattern file.txt

Connect to SQL Server through PDO using SQL Server Driver

This works for me, and in this case was a remote connection: Note: The port was IMPORTANT for me

$dsn = "sqlsrv:Server=server.dyndns.biz,1433;Database=DBNAME";
$conn = new PDO($dsn, "root", "P4sw0rd");
$conn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );

$sql = "SELECT * FROM Table";

foreach ($conn->query($sql) as $row) {
    print_r($row);
} 

How do I switch between command and insert mode in Vim?

Pressing ESC quits from insert mode to normal mode, where you can press : to type in a command. Press i again to back to insert mode, and you are good to go.

I'm not a Vim guru, so someone else can be more experienced and give you other options.

How to Migrate to WKWebView?

Step : 1 Import webkit in ViewController.swift

import WebKit

Step : 2 Declare variable of webView.

var webView : WKWebView!

Step : 3 Adding Delegate of WKNavigationDelegate

class ViewController: UIViewController , WKNavigationDelegate{

Step : 4 Adding code in ViewDidLoad.

let myBlog = "https://iosdevcenters.blogspot.com/"
let url = NSURL(string: myBlog)
let request = NSURLRequest(URL: url!)

// init and load request in webview.
webView = WKWebView(frame: self.view.frame)
webView.navigationDelegate = self
webView.loadRequest(request)
self.view.addSubview(webView)
self.view.sendSubviewToBack(webView)

Step : 5 Edit the info.plist adding

<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
<key>NSExceptionDomains</key>
<dict>
<key>google.com</key>
<dict>
    <key>NSExceptionAllowsInsecureHTTPLoads</key>
    <true/>
    <key>NSIncludesSubdomains</key>
    <true/>
</dict>
</dict>

Detect WebBrowser complete page loading

I had the same issue of multiple DocumentCompleted fired events and tried out all the suggestions above. Finally, seems that in my case neither IsBusy property works right nor Url property, but the ReadyState seems to be what I needed, because it has the status 'Interactive' while loading the multiple frames and it gets the status 'Complete' only after loading the last one. Thus, I know when the page is fully loaded with all its components.

I hope this may help others too :)

C# Dictionary get item by index

Is it useful to look beyond the exact question asked to alternatives that might better suit the need? Create your own class or struct, then make an array of those to operate on instead of being stuck with the operation of the KeyValuePair collection behavior of the Dictionary type.

Using a struct instead of a class will allow equality comparison of two different cards without implementing your own comparison code.

public struct Card
{
  public string Name;
  public int Value;

}

private int random()
{
  // Whatever
  return 1;
}

private static Card[] Cards = new Card[]
{
    new Card() { Name = "7", Value = 7 },
    new Card() { Name = "8", Value = 8 },
    new Card() { Name = "9", Value = 9 },
    new Card() { Name = "10", Value = 10 },
    new Card() { Name = "J", Value = 1 },
    new Card() { Name = "Q", Value = 1 },
    new Card() { Name = "K", Value = 1 },
    new Card() { Name = "A", Value = 1 }
};

private void CardDemo()
{
  int value, maxVal;
  string name;
  Card card, card2;
  List<Card> lowCards;

  value = Cards[random()].Value;
  name = Cards[random()].Name;
  card = Cards[random()];
  card2 = Cards[1];
  // card.Equals(card2) returns true
  lowCards = Cards.Where(x => x.Value == 1).ToList();
  maxVal = Cards.Max(x => x.Value);

}

Call japplet from jframe

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

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

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

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

Updated

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

Within the constructor of GalzyTable2 you are doing...

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

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

Case in point...

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

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

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

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

Take the time to read through Creating a GUI with Swing

Updated with example

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

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

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

How do you read scanf until EOF in C?

For C users, this will also work

while ( gets(str) != NULL )

Google Maps: how to get country, state/province/region, city given a lat/long value?

I used this question as a starting point for my own solution. Thought it was appropriate to contribute my code back since its smaller than tabacitu's

Dependencies:

Code:

if(geoPosition.init()){  

    var foundLocation = function(city, state, country, lat, lon){
        //do stuff with your location! any of the first 3 args may be null
        console.log(arguments);
    }

    var geocoder = new google.maps.Geocoder(); 
    geoPosition.getCurrentPosition(function(r){
        var findResult = function(results, name){
            var result =  _.find(results, function(obj){
                return obj.types[0] == name && obj.types[1] == "political";
            });
            return result ? result.short_name : null;
        };
        geocoder.geocode({'latLng': new google.maps.LatLng(r.coords.latitude, r.coords.longitude)}, function(results, status) {
            if (status == google.maps.GeocoderStatus.OK && results.length) {
                results = results[0].address_components;
                var city = findResult(results, "locality");
                var state = findResult(results, "administrative_area_level_1");
                var country = findResult(results, "country");
                foundLocation(city, state, country, r.coords.latitude, r.coords.longitude);
            } else {
                foundLocation(null, null, null, r.coords.latitude, r.coords.longitude);
            }
        });
    }, { enableHighAccuracy:false, maximumAge: 1000 * 60 * 1 });
}

How do I clear a search box with an 'x' in bootstrap 3?

I tried to avoid too much custom CSS and after reading some other examples I merged the ideas there and got this solution:

<div class="form-group has-feedback has-clear">
    <input type="text" class="form-control" ng-model="ctrl.searchService.searchTerm" ng-change="ctrl.search()" placeholder="Suche"/>
    <a class="glyphicon glyphicon-remove-sign form-control-feedback form-control-clear" ng-click="ctrl.clearSearch()" style="pointer-events: auto; text-decoration: none;cursor: pointer;"></a>
</div>

As I don't use bootstrap's JavaScript, just the CSS together with Angular, I don't need the classes has-clear and form-control-clear, and I implemented the clear function in my AngularJS controller. With bootstrap's JavaScript this might be possible without own JavaScript.

HTML SELECT - Change selected option by VALUE using JavaScript

You can select the value using javascript:

document.getElementById('sel').value = 'bike';

DEMO

How can I delete one element from an array by value

I like the -=[4] way mentioned in other answers to delete the elements whose value is 4.

But there is this way:

[2,4,6,3,8,6].delete_if { |i| i == 6 }
=> [2, 4, 3, 8]

mentioned somewhere in "Basic Array Operations", after it mentions the map function.

What is an idiomatic way of representing enums in Go?

There is a way with struct namespace.

The benefit is all enum variables are under a specific namespace to avoid pollution. The issue is that we could only use var not const

type OrderStatusType string

var OrderStatus = struct {
    APPROVED         OrderStatusType
    APPROVAL_PENDING OrderStatusType
    REJECTED         OrderStatusType
    REVISION_PENDING OrderStatusType
}{
    APPROVED:         "approved",
    APPROVAL_PENDING: "approval pending",
    REJECTED:         "rejected",
    REVISION_PENDING: "revision pending",
}

WARNING: Setting property 'source' to 'org.eclipse.jst.jee.server:appname' did not find a matching property

Despite this question being rather old, I had to deal with a similar warning and wanted to share what I found out.

First of all this is a warning and not an error. So there is no need to worry too much about it. Basically it means, that Tomcat does not know what to do with the source attribute from context.

This source attribute is set by Eclipse (or to be more specific the Eclipse Web Tools Platform) to the server.xml file of Tomcat to match the running application to a project in workspace.

Tomcat generates a warning for every unknown markup in the server.xml (i.e. the source attribute) and this is the source of the warning. You can safely ignore it.

Using parameters in batch files at Windows command line

Batch Files automatically pass the text after the program so long as their are variables to assign them to. They are passed in order they are sent; e.g. %1 will be the first string sent after the program is called, etc.

If you have Hello.bat and the contents are:

@echo off
echo.Hello, %1 thanks for running this batch file (%2)
pause

and you invoke the batch in command via

hello.bat APerson241 %date%

you should receive this message back:

Hello, APerson241 thanks for running this batch file (01/11/2013)

gcc: undefined reference to

However, avpicture_get_size is defined.

No, as the header (<libavcodec/avcodec.h>) just declares it.

The definition is in the library itself.

So you might like to add the linker option to link libavcodec when invoking gcc:

-lavcodec

Please also note that libraries need to be specified on the command line after the files needing them:

gcc -I$HOME/ffmpeg/include program.c -lavcodec

Not like this:

gcc -lavcodec -I$HOME/ffmpeg/include program.c

Referring to Wyzard's comment, the complete command might look like this:

gcc -I$HOME/ffmpeg/include program.c -L$HOME/ffmpeg/lib -lavcodec

For libraries not stored in the linkers standard location the option -L specifies an additional search path to lookup libraries specified using the -l option, that is libavcodec.x.y.z in this case.


For a detailed reference on GCC's linker option, please read here.

Converting UTF-8 to ISO-8859-1 in Java - how to keep it as single byte

If you're dealing with character encodings other than UTF-16, you shouldn't be using java.lang.String or the char primitive -- you should only be using byte[] arrays or ByteBuffer objects. Then, you can use java.nio.charset.Charset to convert between encodings:

Charset utf8charset = Charset.forName("UTF-8");
Charset iso88591charset = Charset.forName("ISO-8859-1");

ByteBuffer inputBuffer = ByteBuffer.wrap(new byte[]{(byte)0xC3, (byte)0xA2});

// decode UTF-8
CharBuffer data = utf8charset.decode(inputBuffer);

// encode ISO-8559-1
ByteBuffer outputBuffer = iso88591charset.encode(data);
byte[] outputData = outputBuffer.array();

Reset all the items in a form

I recently had to do this for Textboxes and Checkboxes but using JavaScript ...

How to reset textbox and checkbox controls in an ASP.net document

Here is the code ...

<script src="http://code.jquery.com/jquery-1.7.1.js" type="text/javascript"></script>

<script type="text/javascript">
      function ResetForm() {
          //get the all the Input type elements in the document
          var AllInputsElements = document.getElementsByTagName('input');
          var TotalInputs = AllInputsElements.length;

          //we have to find the checkboxes and uncheck them
          //note: <asp:checkbox renders to <input type="checkbox" after compiling, which is why we use 'input' above
          for(var i=0;i< TotalInputs ; i++ )
          {
            if(AllInputsElements[i].type =='checkbox')
            {
                AllInputsElements[i].checked = false;
            }
          }

          //reset all textbox controls
          $('input[type=text], textarea').val('');

          Page_ClientValidateReset();
          return false;
      }

      //This function resets all the validation controls so that they don't "fire" up
      //during a post-back.
      function Page_ClientValidateReset() {
          if (typeof (Page_Validators) != "undefined") {
              for (var i = 0; i < Page_Validators.length; i++) {
                  var validator = Page_Validators[i];
                  validator.isvalid = true;
                  ValidatorUpdateDisplay(validator);
              }
          }
      }
</script>

And call it with a button or any other method ...

<asp:button id="btnRESET" runat="server" onclientclick="return ResetForm();" text="RESET" width="100px"></asp:button>

If you don't use ValidationControls on your website, just remove all the code refering to it above and the call Page_ClientValidateReset();

I am sure you can expand it for any other control using the DOM. And since there is no post to the server, it's faster and no "flashing" either.

Using Regular Expressions to Extract a Value in Java

Pattern p = Pattern.compile("(\\D+)(\\d+)(.*)");
Matcher m = p.matcher("this is your number:1234 thank you");
if (m.find()) {
    String someNumberStr = m.group(2);
    int someNumberInt = Integer.parseInt(someNumberStr);
}

Multi-statement Table Valued Function vs Inline Table Valued Function

I have not tested this, but a multi statement function caches the result set. There may be cases where there is too much going on for the optimizer to inline the function. For example suppose you have a function that returns a result from different databases depending on what you pass as a "Company Number". Normally, you could create a view with a union all then filter by company number but I found that sometimes sql server pulls back the entire union and is not smart enough to call the one select. A table function can have logic to choose the source.

Vibrate and Sound defaults on notification

An extension to TeeTracker's answer,

to get the default notification sound you can do as follows

NotificationCompat.Builder mBuilder =
            new NotificationCompat.Builder(this)
            .setSmallIcon(R.drawable.ic_notify)
            .setContentTitle("Device Connected")
            .setContentText("Click to monitor");

Uri alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
builder.setSound(alarmSound);

This will give you the default notification sound.

How do I convert a Django QuerySet into list of dicts?

Use the .values() method:

>>> Blog.objects.values()
[{'id': 1, 'name': 'Beatles Blog', 'tagline': 'All the latest Beatles news.'}],
>>> Blog.objects.values('id', 'name')
[{'id': 1, 'name': 'Beatles Blog'}]

Note: the result is a QuerySet which mostly behaves like a list, but isn't actually an instance of list. Use list(Blog.objects.values(…)) if you really need an instance of list.

Print an integer in binary format in Java

Old school:

    int value = 28;
    for(int i = 1, j = 0; i < 256; i = i << 1, j++)
        System.out.println(j + " " + ((value & i) > 0 ? 1 : 0));

Extract matrix column values by matrix column name

> myMatrix <- matrix(1:10, nrow=2)
> rownames(myMatrix) <- c("A", "B")
> colnames(myMatrix) <- c("A", "B", "C", "D", "E")

> myMatrix
  A B C D  E
A 1 3 5 7  9
B 2 4 6 8 10

> myMatrix["A", "A"]
[1] 1

> myMatrix["A", ]
A B C D E 
1 3 5 7 9 

> myMatrix[, "A"]
A B 
1 2 

Android Dialog: Removing title bar

You can try this simple android dialog popup library. It is very simple to use on your activity.

When submit button is clicked try following code after including above lib in your code

Pop.on(this)
   .with()
   .title(R.string.title) //ignore if not needed
   .icon(R.drawable.icon) //ignore if not needed
   .cancelable(false) //ignore if not needed
   .layout(R.layout.custom_pop)
   .when(new Pop.Yah() {
       @Override
       public void clicked(DialogInterface dialog, View view) {
           Toast.makeText(getBaseContext(), "Yah button clicked", Toast.LENGTH_LONG).show();
       }
   }).show();

Add one line in your gradle and you good to go

dependencies {
    compile 'com.vistrav:pop:2.0'
}

Updating the value of data attribute using jQuery

$('.toggle img').data('block', 'something');
$('.toggle img').attr('src', 'something.jpg');

Use jQuery.data and jQuery.attr.

I'm showing them to you separately for the sake of understanding.

Difference between the 'controller', 'link' and 'compile' functions when defining a directive

compile function -

  1. is called before the controller and link function.
  2. In compile function, you have the original template DOM so you can make changes on original DOM before AngularJS creates an instance of it and before a scope is created
  3. ng-repeat is perfect example - original syntax is template element, the repeated elements in HTML are instances
  4. There can be multiple element instances and only one template element
  5. Scope is not available yet
  6. Compile function can return function and object
  7. returning a (post-link) function - is equivalent to registering the linking function via the link property of the config object when the compile function is empty.
  8. returning an object with function(s) registered via pre and post properties - allows you to control when a linking function should be called during the linking phase. See info about pre-linking and post-linking functions below.

syntax

function compile(tElement, tAttrs, transclude) { ... }

controller

  1. called after the compile function
  2. scope is available here
  3. can be accessed by other directives (see require attribute)

pre - link

  1. The link function is responsible for registering DOM listeners as well as updating the DOM. It is executed after the template has been cloned. This is where most of the directive logic will be put.

  2. You can update the dom in the controller using angular.element but this is not recommended as the element is provided in the link function

  3. Pre-link function is used to implement logic that runs when angular js has already compiled the child elements but before any of the child element's post link have been called

post-link

  1. directive that only has link function, angular treats the function as a post link

  2. post will be executed after compile, controller and pre-link funciton, so that's why this is considered the safest and default place to add your directive logic

MySQL error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near

Delimiters, delimiters...

You really need them when there are multiple statements in your procedure. (in other words, do you have a ; in your code and then more statements/commands? Then, you need to use delimiters).

For such a simpler rpocedure as yours though, you could just do:

CREATE PROCEDURE ProG()
  SELECT * FROM `hs_hr_employee_leave_quota`;

What's is the difference between train, validation and test set, in neural networks?

Training Dataset: The sample of data used to fit the model.

Validation Dataset: The sample of data used to provide an unbiased evaluation of a model fit on the training dataset while tuning model hyperparameters. The evaluation becomes more biased as skill on the validation dataset is incorporated into the model configuration.

Test Dataset: The sample of data used to provide an unbiased evaluation of a final model fit on the training dataset.

Table cell widths - fixing width, wrapping/truncating long words

Stack Overflow has solved a similar problem with long lines of code by using a DIV and having overflow-x:auto. CSS can't break up words for you.

Global npm install location on windows?

According to: https://docs.npmjs.com/files/folders

  • Local install (default): puts stuff in ./node_modules of the current package root.
  • Global install (with -g): puts stuff in /usr/local or wherever node is installed.
  • Install it locally if you're going to require() it.
  • Install it globally if you're going to run it on the command line. -> If you need both, then install it in both places, or use npm link.

prefix Configuration

The prefix config defaults to the location where node is installed. On most systems, this is /usr/local. On windows, this is the exact location of the node.exe binary.

The docs might be a little outdated, but they explain why global installs can end up in different directories:

(dev) go|c:\srv> npm config ls -l | grep prefix
; prefix = "C:\\Program Files\\nodejs" (overridden)
prefix = "C:\\Users\\bjorn\\AppData\\Roaming\\npm"

Based on the other answers, it may seem like the override is now the default location on Windows, and that I may have installed my office version prior to this override being implemented.

This also suggests a solution for getting all team members to have globals stored in the same absolute path relative to their PC, i.e. (run as Administrator):

mkdir %PROGRAMDATA%\npm
setx PATH "%PROGRAMDATA%\npm;%PATH%" /M
npm config set prefix %PROGRAMDATA%\npm

open a new cmd.exe window and reinstall all global packages.

Explanation (by lineno.):

  1. Create a folder in a sensible location to hold the globals (Microsoft is adamant that you shouldn't write to ProgramFiles, so %PROGRAMDATA% seems like the next logical place.
  2. The directory needs to be on the path, so use setx .. /M to set the system path (under HKEY_LOCAL_MACHINE). This is what requires you to run this in a shell with administrator permissions.
  3. Tell npm to use this new path. (Note: folder isn't visible in %PATH% in this shell, so you must open a new window).

Why is it bad practice to call System.gc()?

The reason everyone always says to avoid System.gc() is that it is a pretty good indicator of fundamentally broken code. Any code that depends on it for correctness is certainly broken; any that rely on it for performance are most likely broken.

You don't know what sort of garbage collector you are running under. There are certainly some that do not "stop the world" as you assert, but some JVMs aren't that smart or for various reasons (perhaps they are on a phone?) don't do it. You don't know what it's going to do.

Also, it's not guaranteed to do anything. The JVM may just entirely ignore your request.

The combination of "you don't know what it will do," "you don't know if it will even help," and "you shouldn't need to call it anyway" are why people are so forceful in saying that generally you shouldn't call it. I think it's a case of "if you need to ask whether you should be using this, you shouldn't"


EDIT to address a few concerns from the other thread:

After reading the thread you linked, there's a few more things I'd like to point out. First, someone suggested that calling gc() may return memory to the system. That's certainly not necessarily true - the Java heap itself grows independently of Java allocations.

As in, the JVM will hold memory (many tens of megabytes) and grow the heap as necessary. It doesn't necessarily return that memory to the system even when you free Java objects; it is perfectly free to hold on to the allocated memory to use for future Java allocations.

To show that it's possible that System.gc() does nothing, view:

http://bugs.sun.com/view_bug.do?bug_id=6668279

and in particular that there's a -XX:DisableExplicitGC VM option.

How do I truly reset every setting in Visual Studio 2012?

Just repair Visual Studio itself from the control panel and that should do the trick!

How to use FormData in react-native?

Providing some other solution; we're also using react-native-image-picker; and the server side is using koa-multer; this set-up is working good:

ui

ImagePicker.showImagePicker(options, (response) => {
      if (response.didCancel) {}
      else if (response.error) {}
      else if (response.customButton) {}
      else {
        this.props.addPhoto({ // leads to handleAddPhoto()
          fileName: response.fileName,
          path: response.path,
          type: response.type,
          uri: response.uri,
          width: response.width,
          height: response.height,
        });
      }
    });

handleAddPhoto = (photo) => { // photo is the above object
    uploadImage({ // these 3 properties are required
      uri: photo.uri,
      type: photo.type,
      name: photo.fileName,
    }).then((data) => {
      // ...
    });
  }

client

export function uploadImage(file) { // so uri, type, name are required properties
  const formData = new FormData();
  formData.append('image', file);

  return fetch(`${imagePathPrefix}/upload`, { // give something like https://xx.yy.zz/upload/whatever
    method: 'POST',
    body: formData,
  }
  ).then(
    response => response.json()
  ).then(data => ({
    uri: data.uri,
    filename: data.filename,
  })
  ).catch(
    error => console.log('uploadImage error:', error)
  );
}

server

import multer from 'koa-multer';
import RouterBase from '../core/router-base';

const upload = multer({ dest: 'runtime/upload/' });

export default class FileUploadRouter extends RouterBase {
  setupRoutes({ router }) {
    router.post('/upload', upload.single('image'), async (ctx, next) => {
      const file = ctx.req.file;
      if (file != null) {
        ctx.body = {
          uri: file.filename,
          filename: file.originalname,
        };
      } else {
        ctx.body = {
          uri: '',
          filename: '',
        };
      }
    });
  }
}

How to import multiple csv files in a single load?

Note that you can use other tricks like :

-- One or more wildcard:
       .../Downloads20*/*.csv
--  braces and brackets   
       .../Downloads201[1-5]/book.csv
       .../Downloads201{11,15,19,99}/book.csv

ReferenceError: $ is not defined

It's one of the common mistake everybody make while working with jQuery, Basically $ is an alias of jQuery() so when you try to call/access it before declaring the function will endup throwing this error.

Reasons might be

1) Path to jQuery library you included is not correct.

2) Added library after the script were you see that error

To solve this

Load the jquery library beginning of all your javascript files/scripts.

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

loop through json array jquery

I dont think youre returning json object from server. just a string.

you need the dataType of the return object to be json

PHP Pass by reference in foreach

Because if you create a reference to a variable, all names for that variable (including the original) BECOME REFERENCES.

Replace deprecated preg_replace /e with preg_replace_callback

You can use an anonymous function to pass the matches to your function:

$result = preg_replace_callback(
    "/\{([<>])([a-zA-Z0-9_]*)(\?{0,1})([a-zA-Z0-9_]*)\}(.*)\{\\1\/\\2\}/isU",
    function($m) { return CallFunction($m[1], $m[2], $m[3], $m[4], $m[5]); },
    $result
);

Apart from being faster, this will also properly handle double quotes in your string. Your current code using /e would convert a double quote " into \".

Axios handling errors

call the request function from anywhere without having to use catch().

First, while handling most errors in one place is a good Idea, it's not that easy with requests. Some errors (e.g. 400 validation errors like: "username taken" or "invalid email") should be passed on.

So we now use a Promise based function:

const baseRequest = async (method: string, url: string, data: ?{}) =>
  new Promise<{ data: any }>((resolve, reject) => {
    const requestConfig: any = {
      method,
      data,
      timeout: 10000,
      url,
      headers: {},
    };

    try {
      const response = await axios(requestConfig);
      // Request Succeeded!
      resolve(response);
    } catch (error) {
      // Request Failed!

      if (error.response) {
        // Request made and server responded
        reject(response);
      } else if (error.request) {
        // The request was made but no response was received
        reject(response);
      } else {
        // Something happened in setting up the request that triggered an Error
        reject(response);
      }
    }
  };

you can then use the request like

try {
  response = await baseRequest('GET', 'https://myApi.com/path/to/endpoint')
} catch (error) {
  // either handle errors or don't
}

SQL join on multiple columns in same tables

Join like this:

ON a.userid = b.sourceid AND a.listid = b.destinationid;

Convert an integer to an array of digits

The <= in the for statement should be a <.

BTW, it is possible to do this much more efficiently without using strings, but instead using /10 and %10 of integers.

How to remove index.php from URLs?

If the other solutions don't work for you, try this:

Step 1: (if your installation is in webroot)

Replace

    #RewriteBase /magento/

with

    RewriteBase /

Step 2:

Add following lines (inclusive exclude admin because backend needs index.php internally)

RewriteCond %{THE_REQUEST} ^.*/index.php
RewriteRule ^(.*)index.php$ http://www.yourdomain.com/$1 [R=301,L]
RewriteRule ^index.php/(admin|user)($|/) - [L]
RewriteRule ^index.php/(.*) $1 [R=301,QSA,L]

right after

RewriteRule .* index.php [L] 

This works for me

In case it is still not working, double check Magento configuration: System->Configuration->Web->Search Engine Optimization. Rewrites must be enabled.

How to include a class in PHP

I suggest you also take a look at __autoload.
This will clean up the code of requires and includes.

User Get-ADUser to list all properties and export to .csv

This can be simplified by completely skipping the where object and the $users declaration. All you need is:

Code

get-content c:\scripts\users.txt | get-aduser -properties * | select displayname, office | export-csv c:\path\to\your.csv

How do I write output in same place on the console?

Use a terminal-handling library like the curses module:

The curses module provides an interface to the curses library, the de-facto standard for portable advanced terminal handling.

add item to dropdown list in html using javascript

Since your script is in <head>, you need to wrap it in window.onload:

window.onload = function () {
    var select = document.getElementById("year");
    for(var i = 2011; i >= 1900; --i) {
        var option = document.createElement('option');
        option.text = option.value = i;
        select.add(option, 0);
    }
};

You can also do it in this way

<body onload="addList()">

How to skip the OPTIONS preflight request?

setting the content-type to undefined would make javascript pass the header data As it is , and over writing the default angular $httpProvider header configurations. Angular $http Documentation

$http({url:url,method:"POST", headers:{'Content-Type':undefined}).then(success,failure);

Throughput and bandwidth difference?

Bandwidth is the maximum amount of data that can travel through a 'channel'.

Throughput is how much data actually does travel through the 'channel' successfully. This can be limited by a ton of different things including latency, and what protocol you are using.

How to grep and replace

Another option is to use find and then pass it through sed.

find /path/to/files -type f -exec sed -i 's/oldstring/new string/g' {} \;

What are the differences between a program and an application?

i guess you mean System Programs and Application programs

System Programs makes the hardware run , Applications are for specific tasks

an Example for System Programs are Device Drivers

as for the Applications you can say web browsers , word porcessros etc

How to get difference between two dates in Year/Month/Week/Day?

private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
{

        int gyear = dateTimePicker1.Value.Year; 
        int gmonth = dateTimePicker1.Value.Month; 
        int gday = dateTimePicker1.Value.Day; 
        int syear = DateTime.Now.Year; 
        int smonth = DateTime.Now.Month; 
        int sday = DateTime.Now.Day;

        int difday = DateTime.DaysInMonth(syear, gmonth);

        agedisplay = (syear - gyear); 

        lmonth = (smonth - gmonth);
        lday = (sday - gday);


        if (smonth < gmonth)
        {
            agedisplay = agedisplay - 1;
        }
        if (smonth == gmonth)
        {
            if (sday < (gday))
            {
                agedisplay = agedisplay - 1;
            }
        }

        if (smonth < gmonth)
        {
            lmonth = (-(-smonth)+(-gmonth)+12);
        }
        if (lday < 0)
        {
            lday = difday - (-lday);
            lmonth = lmonth - 1;
        }

        if (smonth == gmonth && sday < gday&&gyear!=syear)
        {
            lmonth = 11;
        }

            ageDisplay.Text = Convert.ToString(agedisplay) + " Years,  " + lmonth + " Months,  " + lday + " Days.";

    }

Detect if value is number in MySQL

You can use regular expression for the mor detail https://dev.mysql.com/doc/refman/8.0/en/regexp.html

I used this ^([,|.]?[0-9])+$. This is allows handle to the decimal and float number

SELECT
    *
FROM
    mytable
WHERE
    myTextField REGEXP "^([,|.]?[0-9])+$"

How can I quickly sum all numbers in a file?

You can use awk:

awk '{ sum += $1 } END { print sum }' file

How to do case insensitive string comparison?

I wrote a extension. very trivial

if (typeof String.prototype.isEqual!= 'function') {
    String.prototype.isEqual = function (str){
        return this.toUpperCase()==str.toUpperCase();
     };
}

How to skip to next iteration in jQuery.each() util?

What they mean by non-false is:

return true;

So this code:

_x000D_
_x000D_
var arr = ["one", "two", "three", "four", "five"];_x000D_
$.each(arr, function(i) {_x000D_
  if (arr[i] == 'three') {_x000D_
    return true;_x000D_
  }_x000D_
  console.log(arr[i]);_x000D_
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
_x000D_
_x000D_
_x000D_

will log one, two, four, five.

How to set layout_gravity programmatically?

I had a similar problem with programmatically setting layout_gravity on buttons in a GridLayout.

The trick was to set gravity on the button layoutParams AFTER the button was added to a parent (GridLayout), otherwise the gravity would be ignored.

grid.addView(button)
((GridLayout.LayoutParams)button.getLayoutParams()).setGravity(int)

mysql_fetch_array() expects parameter 1 to be resource problem

You are not doing error checking after the call to mysql_query:

$result = mysql_query("SELECT * FROM student WHERE IDNO=".$_GET['id']);
if (!$result) { // add this check.
    die('Invalid query: ' . mysql_error());
}

In case mysql_query fails, it returns false, a boolean value. When you pass this to mysql_fetch_array function (which expects a mysql result object) we get this error.

Provide an image for WhatsApp link sharing

I had the same issue and the problem was the size of the picture. Whatsapp doesn't support picture with a size greater than 300KB.

So the most important property to display image on Whatsapp is:

<meta property="og:image" content="url_image">

And the size of the image to display must be less than 300KB.

If the problem persists, read also the answer for this similar question

Multiple Image Upload PHP form with one input

Multiple Image upload using php full source code and preview available at the below Link.
Sample code:

if (isset($_POST['submit'])) {
    $j = 0; //Variable for indexing uploaded image 

    $target_path = "uploads/"; //Declaring Path for uploaded images
    for ($i = 0; $i < count($_FILES['file']['name']); $i++) { //loop to get individual element from the array

        $validextensions = array("jpeg", "jpg", "png"); //Extensions which are allowed
        $ext = explode('.', basename($_FILES['file']['name'][$i])); //explode file name from dot(.) 
        $file_extension = end($ext); //store extensions in the variable

        $target_path = $target_path.md5(uniqid()).
        ".".$ext[count($ext) - 1]; //set the target path with a new name of image
        $j = $j + 1; //increment the number of uploaded images according to the files in array       

        if (($_FILES["file"]["size"][$i] < 100000) //Approx. 100kb files can be uploaded.
            && in_array($file_extension, $validextensions)) {
            if (move_uploaded_file($_FILES['file']['tmp_name'][$i], $target_path)) { //if file moved to uploads folder
                echo $j.
                ').<span id="noerror">Image uploaded successfully!.</span><br/><br/>';
            } else { //if file was not moved.
                echo $j.
                ').<span id="error">please try again!.</span><br/><br/>';
            }
        } else { //if file size and file type was incorrect.
            echo $j.
            ').<span id="error">***Invalid file Size or Type***</span><br/><br/>';
        }
    }
}

http://www.allinworld99.blogspot.com/2015/05/php-multiple-file-upload.html

Installation failed with message Invalid File

None of the answers here worked, I had to:

  1. Close android studio
  2. rm -rf ./android/.idea
  3. Build -> Build Bundle/APK(s) -> Build APK(s)

Search and replace in bash using regular expressions

Use sed:

MYVAR=ho02123ware38384you443d34o3434ingtod38384day
echo "$MYVAR" | sed -e 's/[a-zA-Z]/X/g' -e 's/[0-9]/N/g'
# prints XXNNNNNXXXXNNNNNXXXNNNXNNXNNNNXXXXXXNNNNNXXX

Note that the subsequent -e's are processed in order. Also, the g flag for the expression will match all occurrences in the input.

You can also pick your favorite tool using this method, i.e. perl, awk, e.g.:

echo "$MYVAR" | perl -pe 's/[a-zA-Z]/X/g and s/[0-9]/N/g'

This may allow you to do more creative matches... For example, in the snip above, the numeric replacement would not be used unless there was a match on the first expression (due to lazy and evaluation). And of course, you have the full language support of Perl to do your bidding...

Center a popup window on screen?

_x000D_
_x000D_
.center{_x000D_
    left: 50%;_x000D_
    max-width: 350px;_x000D_
    padding: 15px;_x000D_
    text-align:center;_x000D_
    position: relative;_x000D_
    transform: translateX(-50%);_x000D_
    -moz-transform: translateX(-50%);_x000D_
    -webkit-transform: translateX(-50%);_x000D_
    -ms-transform: translateX(-50%);_x000D_
    -o-transform: translateX(-50%);   _x000D_
}
_x000D_
_x000D_
_x000D_

Update R using RStudio

Just restart R Studio after installing the new version of R. To confirm you're on the new version, >version and you should see the new details.

How to check for an undefined or null variable in JavaScript?

As mentioned in one of the answers, you can be in luck if you are talking about a variable that has a global scope. As you might know, the variables that you define globally tend to get added to the windows object. You can take advantage of this fact so lets say you are accessing a variable called bleh, just use the double inverted operator (!!)

!!window['bleh'];

This would return a false while bleh has not been declared AND assigned a value.

How do I free memory in C?

You actually can't manually "free" memory in C, in the sense that the memory is released from the process back to the OS ... when you call malloc(), the underlying libc-runtime will request from the OS a memory region. On Linux, this may be done though a relatively "heavy" call like mmap(). Once this memory region is mapped to your program, there is a linked-list setup called the "free store" that manages this allocated memory region. When you call malloc(), it quickly looks though the free-store for a free block of memory at the size requested. It then adjusts the linked list to reflect that there has been a chunk of memory taken out of the originally allocated memory pool. When you call free() the memory block is placed back in the free-store as a linked-list node that indicates its an available chunk of memory.

If you request more memory than what is located in the free-store, the libc-runtime will again request more memory from the OS up to the limit of the OS's ability to allocate memory for running processes. When you free memory though, it's not returned back to the OS ... it's typically recycled back into the free-store where it can be used again by another call to malloc(). Thus, if you make a lot of calls to malloc() and free() with varying memory size requests, it could, in theory, cause a condition called "memory fragmentation", where there is enough space in the free-store to allocate your requested memory block, but not enough contiguous space for the size of the block you've requested. Thus the call to malloc() fails, and you're effectively "out-of-memory" even though there may be plenty of memory available as a total amount of bytes in the free-store.

How to write text on a image in windows using python opencv2

Was CV_FONT_HERSHEY_SIMPLEX in cv(1)? Here's all I have available for cv2 "FONT":

FONT_HERSHEY_COMPLEX
FONT_HERSHEY_COMPLEX_SMALL
FONT_HERSHEY_DUPLEX
FONT_HERSHEY_PLAIN
FONT_HERSHEY_SCRIPT_COMPLEX
FONT_HERSHEY_SCRIPT_SIMPLEX
FONT_HERSHEY_SIMPLEX
FONT_HERSHEY_TRIPLEX
FONT_ITALIC

Dropping the 'CV_' seems to work for me.

cv2.putText(image,"Hello World!!!", (x,y), cv2.FONT_HERSHEY_SIMPLEX, 2, 255)

Copy entire directory contents to another directory?

With Groovy, you can leverage Ant to do:

new AntBuilder().copy( todir:'/path/to/destination/folder' ) {
  fileset( dir:'/path/to/src/folder' )
}

AntBuilder is part of the distribution and the automatic imports list which means it is directly available for any groovy code.

Proper usage of .net MVC Html.CheckBoxFor

Place this on your model:

[DisplayName("Electric Fan")]
public bool ElectricFan { get; set; }

private string electricFanRate;

public string ElectricFanRate
{
    get { return electricFanRate ?? (electricFanRate = "$15/month"); }
    set { electricFanRate = value; }
}

And this in your cshtml:

<div class="row">
    @Html.CheckBoxFor(m => m.ElectricFan, new { @class = "" })
    @Html.LabelFor(m => m.ElectricFan, new { @class = "" })
    @Html.DisplayTextFor(m => m.ElectricFanRate)
</div>

Which will output this:

MVC Output If you click on the checkbox or the bold label it will check/uncheck the checkbox

how to save canvas as png image?

I really like Tovask's answer but it doesn't work due to the function having the name download (this answer explains why). I also don't see the point in replacing "data:image/..." with "data:application/...".

The following code has been tested in Chrome and Firefox and seems to work fine in both.

JavaScript:

function prepDownload(a, canvas, name) {
    a.download = name
    a.href = canvas.toDataURL()
}

HTML:

<a href="#" onclick="prepDownload(this, document.getElementById('canvasId'), 'imgName.png')">Download</a>
<canvas id="canvasId"></canvas>

Using braces with dynamic variable names in PHP

I was in a position where I had 6 identical arrays and I needed to pick the right one depending on another variable and then assign values to it. In the case shown here $comp_cat was 'a' so I needed to pick my 'a' array ( I also of course had 'b' to 'f' arrays)

Note that the values for the position of the variable in the array go after the closing brace.

${'comp_cat_'.$comp_cat.'_arr'}[1][0] = "FRED BLOGGS";

${'comp_cat_'.$comp_cat.'_arr'}[1][1] = $file_tidy;

echo 'First array value is '.$comp_cat_a_arr[1][0].' and the second value is .$comp_cat_a_arr[1][1];

How to redirect docker container logs to a single file?

If you work on Windows and use PowerShell (like me), you could use the following line to capture the stdout and stderr:

 docker logs <containerId> | Out-File 'C:/dev/mylog.txt'

I hope it helps someone!

og:type and valid values : constantly being parsed as og:type=website

This started happening to my site after I enabled namespace and custom Open Graph actions and objects. Once you enable it, you lose support for standard object types such as bar, or in my case article. (or it's possible Facebook may have deprecated certain types, I'm not 100% sure) When no supported type is specified, Facebook defaults to website.

To fix this what you need to do is go into your app dashboard, select your app, then go to the Open Graph section. Under "Object Types", define your own types, such as "bar."

Next you will have to change your meta tags to look like this:

<meta property="og:type" content="your_namespace:your_object_type" /> 

If you click on "Get Code" next to the object type in the dashboard, Facebook will provide you with an example of meta tags to use.

Checking during array iteration, if the current element is the last element

$arr = array(1, 'a', 3, 4 => 1, 'b' => 1);
foreach ($arr as $key => $val) {
    echo "{$key} = {$val}" . (end(array_keys($arr))===$key ? '' : ', ');
}
// output: 0 = 1, 1 = a, 2 = 3, 4 = 1, b = 1

Fill remaining vertical space - only CSS

You can just add the overflow:auto option:

#second
{
   width:300px;
   height:100%;
   overflow: auto;
   background-color:#9ACD32;
}

How to check for empty array in vba macro

You can use the below function to check if variant or string array is empty in vba

Function IsArrayAllocated(Arr As Variant) As Boolean
        On Error Resume Next
        IsArrayAllocated = IsArray(Arr) And _
                           Not IsError(LBound(Arr, 1)) And _
                           LBound(Arr, 1) <= UBound(Arr, 1)
End Function

Sample usage

Public Function test()
Dim Arr(1) As String
Arr(0) = "d"
Dim x As Boolean
x = IsArrayAllocated(Arr)
End Function

Python subprocess.Popen "OSError: [Errno 12] Cannot allocate memory"

Have you tried using:

(status,output) = commands.getstatusoutput("ps aux")

I thought this had fixed the exact same problem for me. But then my process ended up getting killed instead of failing to spawn, which is even worse..

After some testing I found that this only occurred on older versions of python: it happens with 2.6.5 but not with 2.7.2

My search had led me here python-close_fds-issue, but unsetting closed_fds had not solved the issue. It is still well worth a read.

I found that python was leaking file descriptors by just keeping an eye on it:

watch "ls /proc/$PYTHONPID/fd | wc -l"

Like you, I do want to capture the command's output, and I do want to avoid OOM errors... but it looks like the only way is for people to use a less buggy version of Python. Not ideal...

Generate random string/characters in JavaScript

If you want just A-Z:

randomAZ(n: number): string {
      return Array(n)
        .fill(null)
        .map(() => Math.random()*100%25 + 'A'.charCodeAt(0))
        .map(a => String.fromCharCode(a))
        .join('')
 }

What ports need to be open for TortoiseSVN to authenticate (clear text) and commit?

What's the first part of your Subversion repository URL?

  • If your URL looks like: http://subversion/repos/, then you're probably going over Port 80.
  • If your URL looks like: https://subversion/repos/, then you're probably going over Port 443.
  • If your URL looks like: svn://subversion/, then you're probably going over Port 3690.
  • If your URL looks like: svn+ssh://subversion/repos/, then you're probably going over Port 22.
  • If your URL contains a port number like: http://subversion/repos:8080, then you're using that port.

I can't guarantee the first four since it's possible to reconfigure everything to use different ports, of if you go through a proxy of some sort.

If you're using a VPN, you may have to configure your VPN client to reroute these to their correct ports. A lot of places don't configure their correctly VPNs to do this type of proxying. It's either because they have some sort of anal-retentive IT person who's being overly security conscious, or because they simply don't know any better. Even worse, they'll give you a client where this stuff can't be reconfigured.

The only way around that is to log into a local machine over the VPN, and then do everything from that system.

Insert default value when parameter is null

Christophe,

The default value on a column is only applied if you don't specify the column in the INSERT statement.

Since you're explicitiy listing the column in your insert statement, and explicity setting it to NULL, that's overriding the default value for that column

What you need to do is "if a null is passed into your sproc then don't attempt to insert for that column".

This is a quick and nasty example of how to do that with some dynamic sql.

Create a table with some columns with default values...

CREATE TABLE myTable (
    always VARCHAR(50),
    value1 VARCHAR(50) DEFAULT ('defaultcol1'),
    value2 VARCHAR(50) DEFAULT ('defaultcol2'),
    value3 VARCHAR(50) DEFAULT ('defaultcol3')
)

Create a SPROC that dynamically builds and executes your insert statement based on input params

ALTER PROCEDURE t_insert (
    @always VARCHAR(50),
    @value1 VARCHAR(50) = NULL,
    @value2 VARCHAR(50) = NULL,
    @value3 VARCAHR(50) = NULL
)
AS 
BEGIN
DECLARE @insertpart VARCHAR(500)
DECLARE @valuepart VARCHAR(500)

SET @insertpart = 'INSERT INTO myTable ('
SET @valuepart = 'VALUES ('

    IF @value1 IS NOT NULL
    BEGIN
        SET @insertpart = @insertpart + 'value1,'
        SET @valuepart = @valuepart + '''' + @value1 + ''', '
    END

    IF @value2 IS NOT NULL
    BEGIN
        SET @insertpart = @insertpart + 'value2,'
        SET @valuepart = @valuepart + '''' + @value2 + ''', '
    END

    IF @value3 IS NOT NULL
    BEGIN
        SET @insertpart = @insertpart + 'value3,'
        SET @valuepart = @valuepart + '''' + @value3 + ''', '
    END

    SET @insertpart = @insertpart + 'always) '
    SET @valuepart = @valuepart + + '''' + @always + ''')'

--print @insertpart + @valuepart
EXEC (@insertpart + @valuepart)
END

The following 2 commands should give you an example of what you want as your outputs...

EXEC t_insert 'alwaysvalue'
SELECT * FROM  myTable

EXEC t_insert 'alwaysvalue', 'val1'
SELECT * FROM  myTable

EXEC t_insert 'alwaysvalue', 'val1', 'val2', 'val3'
SELECT * FROM  myTable

I know this is a very convoluted way of doing what you need to do. You could probably equally select the default value from the InformationSchema for the relevant columns but to be honest, I might consider just adding the default value to param at the top of the procedure

How to build and use Google TensorFlow C++ api

Tensorflow itself only provides very basic examples about C++ APIs.
Here is a good resource which includes examples of datasets, rnn, lstm, cnn and more
tensorflow c++ examples

Check if a key exists inside a json object

There's several ways to do it, depending on your intent.

thisSession.hasOwnProperty('merchant_id'); will tell you if thisSession has that key itself (i.e. not something it inherits from elsewhere)

"merchant_id" in thisSession will tell you if thisSession has the key at all, regardless of where it got it.

thisSession["merchant_id"] will return false if the key does not exist, or if its value evaluates to false for any reason (e.g. if it's a literal false or the integer 0 and so on).

What is the difference between a candidate key and a primary key?

A primary key is a column (or columns) in a table that uniquely identifies the rows in that table.

CUSTOMERS


CustomerNo  FirstName   LastName
1   Sally   Thompson
2   Sally   Henderson
3   Harry   Henderson
4   Sandra  Wellington

For example, in the table above, CustomerNo is the primary key.

The values placed in primary key columns must be unique for each row: no duplicates can be tolerated. In addition, nulls are not allowed in primary key columns.

So, having told you that it is possible to use one or more columns as a primary key, how do you decide which columns (and how many) to choose?

Well there are times when it is advisable or essential to use multiple columns. However, if you cannot see an immediate reason to use multiple columns, then use one. This isn't an absolute rule, it is simply advice. However, primary keys made up of single columns are generally easier to maintain and faster in operation. This means that if you query the database, you will usually get the answer back faster if the tables have single column primary keys.

Next question — which column should you pick? The easiest way to choose a column as a primary key (and a method that is reasonably commonly employed) is to get the database itself to automatically allocate a unique number to each row.

In a table of employees, clearly any column like FirstName is a poor choice since you cannot control employee's first names. Often there is only one choice for the primary key, as in the case above. However, if there is more than one, these can be described as 'candidate keys' — the name reflects that they are candidates for the responsible job of primary key.

How to programmatically send a 404 response with Express/Node?

Updated Answer for Express 4.x

Rather than using res.send(404) as in old versions of Express, the new method is:

res.sendStatus(404);

Express will send a very basic 404 response with "Not Found" text:

HTTP/1.1 404 Not Found
X-Powered-By: Express
Vary: Origin
Content-Type: text/plain; charset=utf-8
Content-Length: 9
ETag: W/"9-nR6tc+Z4+i9RpwqTOwvwFw"
Date: Fri, 23 Oct 2015 20:08:19 GMT
Connection: keep-alive

Not Found

Accessing a Dictionary.Keys Key through a numeric index

The way you worded the question leads me to believe that the int in the Dictionary contains the item's "position" on the Dictionary. Judging from the assertion that the keys aren't stored in the order that they're added, if this is correct, that would mean that keys.Count (or .Count - 1, if you're using zero-based) should still always be the number of the last-entered key?

If that's correct, is there any reason you can't instead use Dictionary<int, string> so that you can use mydict[ mydict.Keys.Count ]?

Controlling Maven final name of jar artifact

At the package stage, the plugin allows configuration of the imported file names via file mapping:

maven-ear-plugin

http://maven.apache.org/plugins/maven-ear-plugin/examples/customize-file-name-mapping.html

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-ear-plugin</artifactId>
    <version>2.7</version>
    <configuration>
       [...]
        <fileNameMapping>full</fileNameMapping>
    </configuration>
</plugin>

http://maven.apache.org/plugins/maven-war-plugin/war-mojo.html#outputFileNameMapping

If you have configured your version to be 'testing' via a profile or something, this would work for a war package:

maven-war-plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-war-plugin</artifactId>
    <version>2.2</version>
    <configuration>
        <encoding>UTF-8</encoding>                        
        <outputFileNameMapping>@{groupId}@-@{artifactId}@-@{baseVersion}@@{dashClassifier?}@.@{extension}@</outputFileNameMapping>
    </configuration>
</plugin>

Get remote registry value

If you need user's SID and browse remote HKEY_USERS folder, you can follow this script :

<# Replace following domain.name with yours and userAccountName with remote username #>
$userLogin = New-Object System.Security.Principal.NTAccount(“domain.name“,”userAccountName“)
$userSID = $userLogin.Translate([System.Security.Principal.SecurityIdentifier])

<# We will open HKEY_USERS and with accurate user’s SID from remoteComputer #>
$remoteRegistry = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey(‘Users’,”remoteComputer“)

<# We will then retrieve LocalName value from Control Panel / International subkeys #>

$key = $userSID.value+”\Control Panel\International”
$openKey = $remoteRegistry.OpenSubKey($key)

<# We can now retrieve any values #>

$localName = $openKey.GetValue(‘LocaleName’)

Source : http://techsultan.com/how-to-browse-remote-registry-in-powershell/

How to add a custom Ribbon tab using VBA?

I was able to accomplish this with VBA in Excel 2013. No special editors needed. All you need is the Visual Basic code editor which can be accessed on the Developer tab. The Developer tab is not visible by default so it needs to be enabled in File>Options>Customize Ribbon. On the Developer tab, click the Visual Basic button. The code editor will launch. Right click in the Project Explorer pane on the left. Click the insert menu and choose module. Add both subs below to the new module.

Sub LoadCustRibbon()

Dim hFile As Long
Dim path As String, fileName As String, ribbonXML As String, user As String

hFile = FreeFile
user = Environ("Username")
path = "C:\Users\" & user & "\AppData\Local\Microsoft\Office\"
fileName = "Excel.officeUI"

ribbonXML = "<mso:customUI      xmlns:mso='http://schemas.microsoft.com/office/2009/07/customui'>" & vbNewLine
ribbonXML = ribbonXML + "  <mso:ribbon>" & vbNewLine
ribbonXML = ribbonXML + "    <mso:qat/>" & vbNewLine
ribbonXML = ribbonXML + "    <mso:tabs>" & vbNewLine
ribbonXML = ribbonXML + "      <mso:tab id='reportTab' label='Reports' insertBeforeQ='mso:TabFormat'>" & vbNewLine
ribbonXML = ribbonXML + "        <mso:group id='reportGroup' label='Reports' autoScale='true'>" & vbNewLine
ribbonXML = ribbonXML + "          <mso:button id='runReport' label='PTO' "   & vbNewLine
ribbonXML = ribbonXML + "imageMso='AppointmentColor3'      onAction='GenReport'/>" & vbNewLine
ribbonXML = ribbonXML + "        </mso:group>" & vbNewLine
ribbonXML = ribbonXML + "      </mso:tab>" & vbNewLine
ribbonXML = ribbonXML + "    </mso:tabs>" & vbNewLine
ribbonXML = ribbonXML + "  </mso:ribbon>" & vbNewLine
ribbonXML = ribbonXML + "</mso:customUI>"

ribbonXML = Replace(ribbonXML, """", "")

Open path & fileName For Output Access Write As hFile
Print #hFile, ribbonXML
Close hFile

End Sub

Sub ClearCustRibbon()

Dim hFile As Long
Dim path As String, fileName As String, ribbonXML As String, user As String

hFile = FreeFile
user = Environ("Username")
path = "C:\Users\" & user & "\AppData\Local\Microsoft\Office\"
fileName = "Excel.officeUI"

ribbonXML = "<mso:customUI           xmlns:mso=""http://schemas.microsoft.com/office/2009/07/customui"">" & _
"<mso:ribbon></mso:ribbon></mso:customUI>"

Open path & fileName For Output Access Write As hFile
Print #hFile, ribbonXML
Close hFile

End Sub

Call LoadCustRibbon sub in the Wookbook open even and call the ClearCustRibbon sub in the Before_Close Event of the ThisWorkbook code file.

Error ITMS-90717: "Invalid App Store Icon"

I faced the same problem and wasn't able to fix it with the provided solution by Shamsudheen TK. Ionic somehow added transparency to my icons even if the source icon did not have any transparency at all. In the end I was able to resolve it by:

Install imagemagick (MacOS):

brew install imagemagick

Remove alpha channel from all images in resource folder:

find ./resources/ -name "*.png" -exec convert "{}" -alpha off "{}" \;

Reading large text files with streams in C#

You might be better off to use memory-mapped files handling here.. The memory mapped file support will be around in .NET 4 (I think...I heard that through someone else talking about it), hence this wrapper which uses p/invokes to do the same job..

Edit: See here on the MSDN for how it works, here's the blog entry indicating how it is done in the upcoming .NET 4 when it comes out as release. The link I have given earlier on is a wrapper around the pinvoke to achieve this. You can map the entire file into memory, and view it like a sliding window when scrolling through the file.

SQL - Rounding off to 2 decimal places

Could you not cast your result as numeric(x,2)? Where x <= 38

select 
    round(630/60.0,2), 
    cast(round(630/60.0,2) as numeric(36,2))

Returns

10.500000   10.50

Is Ruby pass by reference or by value?

Two references refer to same object as long as there is no reassignment. 

Any updates in the same object won't make the references to new memory since it still is in same memory. Here are few examples :

    a = "first string"
    b = a



    b.upcase! 
    => FIRST STRING
    a
    => FIRST STRING

    b = "second string"


a
    => FIRST STRING
    hash = {first_sub_hash: {first_key: "first_value"}}
first_sub_hash = hash[:first_sub_hash]
first_sub_hash[:second_key] = "second_value"

    hash
    => {first_sub_hash: {first_key: "first_value", second_key: "second_value"}}

    def change(first_sub_hash)
    first_sub_hash[:third_key] = "third_value"
    end

    change(first_sub_hash)

    hash
    =>  {first_sub_hash: {first_key: "first_value", second_key: "second_value", third_key: "third_value"}}

vim - How to delete a large block of text without counting the lines?

There are several possibilities, what's best depends on the text you work on.

Two possibilities come to mind:

  • switch to visual mode (V, S-V, ...), select the text with cursor movement and press d
  • delete a whole paragraph with: dap

Python: How to remove empty lists from a list?

I found this question because I wanted to do the same as the OP. I would like to add the following observation:

The iterative way (user225312, Sven Marnach):

list2 = [x for x in list1 if x]

Will return a list object in python3 and python2 . Instead the filter way (lunaryorn, Imran) will differently behave over versions:

list2 = filter(None, list1)

It will return a filter object in python3 and a list in python2 (see this question found at the same time). This is a slight difference but it must be take in account when developing compatible scripts.

This does not make any assumption about performances of those solutions. Anyway the filter object can be reverted to a list using:

list3 = list(list2)

Babel command not found

I ran into the very same problem, tried out really everything that I could think of. Not being a fan of installing anything globally, but eventually had to run npm install -g babel-cli, which solved my problem. Maybe not the answer, but definitely a possible solution...

how to show alternate image if source image is not found? (onerror working in IE but not in mozilla)

I think this is very nice and short

<img src="imagenotfound.gif" alt="Image not found" onerror="this.src='imagefound.gif';" />

But, be careful. The user's browser will be stuck in an endless loop if the onerror image itself generates an error.


EDIT To avoid endless loop, remove the onerror from it at once.

<img src="imagenotfound.gif" alt="Image not found" onerror="this.onerror=null;this.src='imagefound.gif';" />

By calling this.onerror=null it will remove the onerror then try to get the alternate image.


NEW I would like to add a jQuery way, if this can help anyone.

<script>
$(document).ready(function()
{
    $(".backup_picture").on("error", function(){
        $(this).attr('src', './images/nopicture.png');
    });
});
</script>

<img class='backup_picture' src='./images/nonexistent_image_file.png' />

You simply need to add class='backup_picture' to any img tag that you want a backup picture to load if it tries to show a bad image.

List of special characters for SQL LIKE clause

ANSI SQL92:

  • %
  • _
  • an ESCAPE character only if specified.

It is disappointing that many databases do not stick to the standard rules and add extra characters, or incorrectly enable ESCAPE with a default value of ‘\’ when it is missing. Like we don't already have enough trouble with ‘\’!

It's impossible to write DBMS-independent code here, because you don't know what characters you're going to have to escape, and the standard says you can't escape things that don't need to be escaped. (See section 8.5/General Rules/3.a.ii.)

Thank you SQL! gnnn

In PHP with PDO, how to check the final SQL parametrized query?

What I did to print that actual query is a bit complicated but it works :)

In method that assigns variables to my statement I have another variable that looks a bit like this:

$this->fullStmt = str_replace($column, '\'' . str_replace('\'', '\\\'', $param) . '\'', $this->fullStmt);

Where:
$column is my token
$param is the actual value being assigned to token
$this->fullStmt is my print only statement with replaced tokens

What it does is a simply replace tokens with values when the real PDO assignment happens.

I hope I did not confuse you and at least pointed you in right direction.

How to label scatterplot points by name?

Another convoluted answer which should technically work and is ok for a small number of data points is to plot all your data points as 1 series in order to get your connecting line. Then plot each point as its own series. Then format data labels to display series name for each of the individual data points.

In short it works ok for a small data set or just key points from a data set.

Blocking device rotation on mobile web pages

In JavaScript-enabled browsers it should be easy to determine if the screen is in landscape or portrait mode and compensate using CSS. It may be helpful to give users the option to disable this or at least warn them that device rotation will not work properly.

Edit

The easiest way to detect the orientation of the browser is to check the width of the browser versus the height of the browser. This also has the advantage that you'll know if the game is being played on a device that is naturally oriented in landscape mode (as some mobile devices like the PSP are). This makes more sense than trying to disable device rotation.

Edit 2

Daz has shown how you can detect device orientation, but detecting orientation is only half of the solution. If want to reverse the automatic orientation change, you'll need to rotate everything either 90° or 270°/-90°, e.g.

$(window).bind('orientationchange resize', function(event){
  if (event.orientation) {
    if (event.orientation == 'landscape') {
      if (window.rotation == 90) {
        rotate(this, -90);
      } else {
        rotate(this, 90);
      }
    }
  }
});

function rotate(el, degs) {
  iedegs = degs/90;
  if (iedegs < 0) iedegs += 4;
  transform = 'rotate('+degs+'deg)';
  iefilter = 'progid:DXImageTransform.Microsoft.BasicImage(rotation='+iedegs+')';
  styles = {
    transform: transform,
    '-webkit-transform': transform,
    '-moz-transform': transform,
    '-o-transform': transform,
    filter: iefilter,
    '-ms-filter': iefilter
  };
  $(el).css(styles);
}

Note: if you want to rotate in IE by an arbitrary angle (for other purposes), you'll need to use matrix transform, e.g.

rads = degs * Math.PI / 180;
m11 = m22 = Math.cos(rads);
m21 = Math.sin(rads);
m12 = -m21;
iefilter = "progid:DXImageTransform.Microsoft.Matrix("
  + "M11 = " + m11 + ", "
  + "M12 = " + m12 + ", "
  + "M21 = " + m21 + ", "
  + "M22 = " + m22 + ", sizingMethod = 'auto expand')";
styles['filter'] = styles['-ms-filter'] = iefilter;

—or use CSS Sandpaper. Also, this applies the rotation style to the window object, which I've never actually tested and don't know if works or not. You may need to apply the style to a document element instead.

Anyway, I would still recommend simply displaying a message that asks the user to play the game in portrait mode.

Generic XSLT Search and Replace template

Here's one way in XSLT 2

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

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

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

How to resolve Nodejs: Error: ENOENT: no such file or directory

After going through so many links and threads and getting frustrated over and over again, I went to the basics and boom! it helped. I simply did:

npm install

I don't know, but it might help someone :)

Download file from web in Python 3

Yes, definietly requests is great package to use in something related to HTTP requests. but we need to be careful with the encoding type of the incoming data as well below is an example which explains the difference


from requests import get

# case when the response is byte array
url = 'some_image_url'

response = get(url)
with open('output', 'wb') as file:
    file.write(response.content)


# case when the response is text
# Here unlikely if the reponse content is of type **iso-8859-1** we will have to override the response encoding
url = 'some_page_url'

response = get(url)
# override encoding by real educated guess as provided by chardet
r.encoding = r.apparent_encoding

with open('output', 'w', encoding='utf-8') as file:
    file.write(response.content)

CAST to DECIMAL in MySQL

If you need a lot of decimal numbers, in this example 17, I share with you MySql code:

This is the calculate:

=(9/1147)*100

SELECT TRUNCATE(((CAST(9 AS DECIMAL(30,20))/1147)*100),17);

Toolbar Navigation Hamburger Icon missing

Use this constructor in MyActionBarDrawerToggle :

    public MyActionBarDrawerToggle(AppCompatActivity host, DrawerLayout drawerlayout, SupportToolbar toolbar, int openedResource, int closedResource)
        : base(host, drawerlayout, toolbar, openedResource, closedResource)
    {
        mHostActivity = host;
        mOpenedResource = openedResource;
        mClosedResource = closedResource;
    }

and Call this method in teh mainActivity (Using AppCompatActivity)

        mDrawerToggle = new MyActionBarDrawerToggle(
            this,                           //Host Activity
            mDrawerLayout,                  //DrawerLayout
            mToolbar,                       //Toolbar
            Resource.String.openDrawer,     //Opened Message
            Resource.String.closeDrawer     //Closed Message
        );


        mDrawerLayout.AddDrawerListener(mDrawerToggle);
        SupportActionBar.SetHomeButtonEnabled(true);
        SupportActionBar.SetDisplayShowTitleEnabled(true);
        mDrawerToggle.DrawerIndicatorEnabled = true;
        mDrawerToggle.SyncState();

What does a lazy val do?

This feature helps not only delaying expensive calculations, but is also useful to construct mutual dependent or cyclic structures. E.g. this leads to an stack overflow:

trait Foo { val foo: Foo }
case class Fee extends Foo { val foo = Faa() }
case class Faa extends Foo { val foo = Fee() }

println(Fee().foo)
//StackOverflowException

But with lazy vals it works fine

trait Foo { val foo: Foo }
case class Fee extends Foo { lazy val foo = Faa() }
case class Faa extends Foo { lazy val foo = Fee() }

println(Fee().foo)
//Faa()

Where does MAMP keep its php.ini?

On my mac, running MAMP I have a few locations that would be the likely php.ini, so I edited the memory_limit to different values in the 2 suspected files, to test which one effected the actual MAMP PHP INFO page details. By doing that I was able to determine that this was the correct php.ini: /Applications/MAMP/bin/php/php7.2.10/conf/php.ini

com.google.android.gms:play-services-measurement-base is being requested by various other libraries

In my case, this solves the issue:

implementation 'com.google.android.gms:play-services-analytics:16.0.1'

Django - "no module named django.core.management"

I had the same problem and following worked good, you should navigate main folder in your project than type:

source bin/activate 

Flask - Calling python function on button OnClick event

It sounds like you want to use this web application as a remote control for your robot, and a core issue is that you won't want a page reload every time you perform an action, in which case, the last link you posted answers your problem.

I think you may be misunderstanding a few things about Flask. For one, you can't nest multiple functions in a single route. You're not making a set of functions available for a particular route, you're defining the one specific thing the server will do when that route is called.

With that in mind, you would be able to solve your problem with a page reload by changing your app.py to look more like this:

from flask import Flask, render_template, Response, request, redirect, url_for
app = Flask(__name__)

@app.route("/")
def index():
    return render_template('index.html')

@app.route("/forward/", methods=['POST'])
def move_forward():
    #Moving forward code
    forward_message = "Moving Forward..."
    return render_template('index.html', forward_message=forward_message);

Then in your html, use this:

<form action="/forward/" method="post">
    <button name="forwardBtn" type="submit">Forward</button>
</form>

...To execute your moving forward code. And include this:

{{ forward_message }} 

... where you want the moving forward message to appear on your template.

This will cause your page to reload, which is inevitable without using AJAX and Javascript.

Regex to match any character including new lines

Yeap, you just need to make . match newline :

$string =~ /(START)(.+?)(END)/s;

Passing properties by reference in C#

This is not possible. You could say

Client.WorkPhone = GetString(inputString, Client.WorkPhone);

where WorkPhone is a writeable string property and the definition of GetString is changed to

private string GetString(string input, string current) { 
    if (!string.IsNullOrEmpty(input)) {
        return input;
    }
    return current;
}

This will have the same semantics that you seem to be trying for.

This isn't possible because a property is really a pair of methods in disguise. Each property makes available getters and setters that are accessible via field-like syntax. When you attempt to call GetString as you've proposed, what you're passing in is a value and not a variable. The value that you are passing in is that returned from the getter get_WorkPhone.

HTML5 LocalStorage: Checking if a key exists

The MDN documentation shows how the getItem method is implementated:

Object.defineProperty(oStorage, "getItem", {
      value: function (sKey) { return sKey ? this[sKey] : null; },
      writable: false,
      configurable: false,
      enumerable: false
    });

If the value isn't set, it returns null. You are testing to see if it is undefined. Check to see if it is null instead.

if(localStorage.getItem("username") === null){

Git error on git pull (unable to update local ref)

Try to use this command in your git repository root folder:

rm .git/logs/refs/remotes/origin/master 

Swift add icon/image in UITextField

Swift 3.1

extension UITextField
{
    enum Direction
    {
        case Left
        case Right
    }

    func AddImage(direction:Direction,imageName:String,Frame:CGRect,backgroundColor:UIColor)
    {
        let View = UIView(frame: Frame)
        View.backgroundColor = backgroundColor

        let imageView = UIImageView(frame: Frame)
        imageView.image = UIImage(named: imageName)

        View.addSubview(imageView)

        if Direction.Left == direction
        {
            self.leftViewMode = .always
            self.leftView = View
        }
        else
        {
            self.rightViewMode = .always
            self.rightView = View
        }
    }

}

Gradle failed to resolve library in Android Studio

Well, it's co.lemonlabs, you have a typo in your build.gradle:

compile 'co.lemonlabs:expandable-button-menu:1.0.0'

Source: https://github.com/lemonlabs/ExpandableButtonMenu#including-in-your-project

How do you set, clear, and toggle a single bit?

Using the Standard C++ Library: std::bitset<N>.

Or the Boost version: boost::dynamic_bitset.

There is no need to roll your own:

#include <bitset>
#include <iostream>

int main()
{
    std::bitset<5> x;

    x[1] = 1;
    x[2] = 0;
    // Note x[0-4]  valid

    std::cout << x << std::endl;
}

[Alpha:] > ./a.out
00010

The Boost version allows a runtime sized bitset compared with a standard library compile-time sized bitset.

How to fix: Handler "PageHandlerFactory-Integrated" has a bad module "ManagedPipelineHandler" in its module list

in some scenario this error occurs because the Microsoft .NET Framework 4.0 configuration for ASP .NET has been damaged, which can occur if Microsoft Visual Studio 2012 was installed before Visual Studio 2010 or Microsoft SQL Server 2008.

After trying different things i reached the conclusion, repair you .Net installation by running following command. For more information follow the link.

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\SetupCache\v4.5.51209\setup.exe /repair /x86 /x64 /ia64 /norestart

https://msdn.microsoft.com/en-us/library/hh168535(v=nav.80).aspx

ERROR 1115 (42000): Unknown character set: 'utf8mb4'

This can help:

mysqldump --compatible=mysql40 -u user -p DB > dumpfile.sql

PHPMyAdmin has the same MySQL compatibility mode in the 'expert' export options. Although that has on occasions done nothing.

If you don't have access via the command line or via PHPMyAdmin then editing the

/*!50003 SET character_set_client  = utf8mb4 */ ; 

bit to read 'utf8' only, is the way to go.

Get IFrame's document, from JavaScript in main document

The problem is that in IE (which is what I presume you're testing in), the <iframe> element has a document property that refers to the document containing the iframe, and this is getting used before the contentDocument or contentWindow.document properties. What you need is:

function GetDoc(x) {
    return x.contentDocument || x.contentWindow.document;
}

Also, document.all is not available in all browsers and is non-standard. Use document.getElementById() instead.

PHP: Show yes/no confirmation dialog

If you're deleting something, you should always use POST and not GET, so using confirm() is a bad idea. What I do in your situation is use a modal popup like jqModal and display a form with yes/no buttons inside the popup.

How to run a method every X seconds

Here I used a thread in onCreate() an Activity repeatly, timer does not allow everything in some cases Thread is the solution

     Thread t = new Thread() {
        @Override
        public void run() {
            while (!isInterrupted()) {
                try {
                    Thread.sleep(10000);  //1000ms = 1 sec
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {

                            SharedPreferences mPrefs = getSharedPreferences("sam", MODE_PRIVATE);
                            Gson gson = new Gson();
                            String json = mPrefs.getString("chat_list", "");
                            GelenMesajlar model = gson.fromJson(json, GelenMesajlar.class);
                            String sam = "";

                            ChatAdapter adapter = new ChatAdapter(Chat.this, model.getData());
                            listview.setAdapter(adapter);
                           // listview.setStackFromBottom(true);
                          //  Util.showMessage(Chat.this,"Merhabalar");
                        }
                    });

                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    };

    t.start();

In case it needed it can be stoped by

@Override
protected void onDestroy() {
    super.onDestroy();
    Thread.interrupted();
    //t.interrupted();
}

ANTLR: Is there a simple example?

Note: this answer is for ANTLR3! If you're looking for an ANTLR4 example, then this Q&A demonstrates how to create a simple expression parser, and evaluator using ANTLR4.


You first create a grammar. Below is a small grammar that you can use to evaluate expressions that are built using the 4 basic math operators: +, -, * and /. You can also group expressions using parenthesis.

Note that this grammar is just a very basic one: it does not handle unary operators (the minus in: -1+9) or decimals like .99 (without a leading number), to name just two shortcomings. This is just an example you can work on yourself.

Here's the contents of the grammar file Exp.g:

grammar Exp;

/* This will be the entry point of our parser. */
eval
    :    additionExp
    ;

/* Addition and subtraction have the lowest precedence. */
additionExp
    :    multiplyExp 
         ( '+' multiplyExp 
         | '-' multiplyExp
         )* 
    ;

/* Multiplication and division have a higher precedence. */
multiplyExp
    :    atomExp
         ( '*' atomExp 
         | '/' atomExp
         )* 
    ;

/* An expression atom is the smallest part of an expression: a number. Or 
   when we encounter parenthesis, we're making a recursive call back to the
   rule 'additionExp'. As you can see, an 'atomExp' has the highest precedence. */
atomExp
    :    Number
    |    '(' additionExp ')'
    ;

/* A number: can be an integer value, or a decimal value */
Number
    :    ('0'..'9')+ ('.' ('0'..'9')+)?
    ;

/* We're going to ignore all white space characters */
WS  
    :   (' ' | '\t' | '\r'| '\n') {$channel=HIDDEN;}
    ;

(Parser rules start with a lower case letter, and lexer rules start with a capital letter)

After creating the grammar, you'll want to generate a parser and lexer from it. Download the ANTLR jar and store it in the same directory as your grammar file.

Execute the following command on your shell/command prompt:

java -cp antlr-3.2.jar org.antlr.Tool Exp.g

It should not produce any error message, and the files ExpLexer.java, ExpParser.java and Exp.tokens should now be generated.

To see if it all works properly, create this test class:

import org.antlr.runtime.*;

public class ANTLRDemo {
    public static void main(String[] args) throws Exception {
        ANTLRStringStream in = new ANTLRStringStream("12*(5-6)");
        ExpLexer lexer = new ExpLexer(in);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        ExpParser parser = new ExpParser(tokens);
        parser.eval();
    }
}

and compile it:

// *nix/MacOS
javac -cp .:antlr-3.2.jar ANTLRDemo.java

// Windows
javac -cp .;antlr-3.2.jar ANTLRDemo.java

and then run it:

// *nix/MacOS
java -cp .:antlr-3.2.jar ANTLRDemo

// Windows
java -cp .;antlr-3.2.jar ANTLRDemo

If all goes well, nothing is being printed to the console. This means the parser did not find any error. When you change "12*(5-6)" into "12*(5-6" and then recompile and run it, there should be printed the following:

line 0:-1 mismatched input '<EOF>' expecting ')'

Okay, now we want to add a bit of Java code to the grammar so that the parser actually does something useful. Adding code can be done by placing { and } inside your grammar with some plain Java code inside it.

But first: all parser rules in the grammar file should return a primitive double value. You can do that by adding returns [double value] after each rule:

grammar Exp;

eval returns [double value]
    :    additionExp
    ;

additionExp returns [double value]
    :    multiplyExp 
         ( '+' multiplyExp 
         | '-' multiplyExp
         )* 
    ;

// ...

which needs little explanation: every rule is expected to return a double value. Now to "interact" with the return value double value (which is NOT inside a plain Java code block {...}) from inside a code block, you'll need to add a dollar sign in front of value:

grammar Exp;

/* This will be the entry point of our parser. */
eval returns [double value]                                                  
    :    additionExp { /* plain code block! */ System.out.println("value equals: "+$value); }
    ;

// ...

Here's the grammar but now with the Java code added:

grammar Exp;

eval returns [double value]
    :    exp=additionExp {$value = $exp.value;}
    ;

additionExp returns [double value]
    :    m1=multiplyExp       {$value =  $m1.value;} 
         ( '+' m2=multiplyExp {$value += $m2.value;} 
         | '-' m2=multiplyExp {$value -= $m2.value;}
         )* 
    ;

multiplyExp returns [double value]
    :    a1=atomExp       {$value =  $a1.value;}
         ( '*' a2=atomExp {$value *= $a2.value;} 
         | '/' a2=atomExp {$value /= $a2.value;}
         )* 
    ;

atomExp returns [double value]
    :    n=Number                {$value = Double.parseDouble($n.text);}
    |    '(' exp=additionExp ')' {$value = $exp.value;}
    ;

Number
    :    ('0'..'9')+ ('.' ('0'..'9')+)?
    ;

WS  
    :   (' ' | '\t' | '\r'| '\n') {$channel=HIDDEN;}
    ;

and since our eval rule now returns a double, change your ANTLRDemo.java into this:

import org.antlr.runtime.*;

public class ANTLRDemo {
    public static void main(String[] args) throws Exception {
        ANTLRStringStream in = new ANTLRStringStream("12*(5-6)");
        ExpLexer lexer = new ExpLexer(in);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        ExpParser parser = new ExpParser(tokens);
        System.out.println(parser.eval()); // print the value
    }
}

Again (re) generate a fresh lexer and parser from your grammar (1), compile all classes (2) and run ANTLRDemo (3):

// *nix/MacOS
java -cp antlr-3.2.jar org.antlr.Tool Exp.g   // 1
javac -cp .:antlr-3.2.jar ANTLRDemo.java      // 2
java -cp .:antlr-3.2.jar ANTLRDemo            // 3

// Windows
java -cp antlr-3.2.jar org.antlr.Tool Exp.g   // 1
javac -cp .;antlr-3.2.jar ANTLRDemo.java      // 2
java -cp .;antlr-3.2.jar ANTLRDemo            // 3

and you'll now see the outcome of the expression 12*(5-6) printed to your console!

Again: this is a very brief explanation. I encourage you to browse the ANTLR wiki and read some tutorials and/or play a bit with what I just posted.

Good luck!

EDIT:

This post shows how to extend the example above so that a Map<String, Double> can be provided that holds variables in the provided expression.

To get this code working with a current version of Antlr (June 2014) I needed to make a few changes. ANTLRStringStream needed to become ANTLRInputStream, the returned value needed to change from parser.eval() to parser.eval().value, and I needed to remove the WS clause at the end, because attribute values such as $channel are no longer allowed to appear in lexer actions.

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

Apart from the apparent difference of

  • having to declare the value at the time of a definition for a const VS readonly values can be computed dynamically but need to be assigned before the constructor exits.. after that it is frozen.
  • 'const's are implicitly static. You use a ClassName.ConstantName notation to access them.

There is a subtle difference. Consider a class defined in AssemblyA.

public class Const_V_Readonly
{
  public const int I_CONST_VALUE = 2;
  public readonly int I_RO_VALUE;
  public Const_V_Readonly()
  {
     I_RO_VALUE = 3;
  }
}

AssemblyB references AssemblyA and uses these values in code. When this is compiled,

  • in the case of the const value, it is like a find-replace, the value 2 is 'baked into' the AssemblyB's IL. This means that if tomorrow I'll update I_CONST_VALUE to 20 in the future. AssemblyB would still have 2 till I recompile it.
  • in the case of the readonly value, it is like a ref to a memory location. The value is not baked into AssemblyB's IL. This means that if the memory location is updated, AssemblyB gets the new value without recompilation. So if I_RO_VALUE is updated to 30, you only need to build AssemblyA. All clients do not need to be recompiled.

So if you are confident that the value of the constant won't change use a const.

public const int CM_IN_A_METER = 100;

But if you have a constant that may change (e.g. w.r.t. precision).. or when in doubt, use a readonly.

public readonly float PI = 3.14;

Update: Aku needs to get a mention coz he pointed this out first. Also I need to plug where I learned this.. Effective C# - Bill Wagner

Decode Base64 data in Java

As of v6, Java SE ships with JAXB. javax.xml.bind.DatatypeConverter has static methods that make this easy. See parseBase64Binary() and printBase64Binary().

Drop shadow on a div container?

you might want to try this. Seems to be pretty easy and works on IE6 and Moz atleast.

<div id ="show" style="background-color:Silver;width:100px;height:100px;visibility:visible;border-bottom:outset 1px black;border-right:outset 1px black;" ></div>

The general syntax is : border-[postion]:[border-style] [border-width] [border-color] | inherit

The list of available [border-style]s are :

  • dashed
  • dotted
  • double
  • groove
  • hidden
  • inset
  • none
  • outset
  • ridge
  • solid
  • inherit

How can I save a screenshot directly to a file in Windows?

Little known fact: in most standard Windows (XP) dialogs, you can hit Ctrl+C to have a textual copy of the content of the dialog.
Example: open a file in Notepad, hit space, close the window, hit Ctrl+C on the Confirm Exit dialog, cancel, paste in Notepad the text of the dialog.
Unrelated to your direct question, but I though it would be nice to mention in this thread.

Beside, indeed, you need a third party software to do the screenshot, but you don't need to fire the big Photoshop for that. Something free and lightweight like IrfanWiew or XnView can do the job. I use MWSnap to copy arbitrary parts of the screen. I wrote a little AutoHotkey script calling GDI+ functions to do screenshots. Etc.

Angular get object from array by Id

// Used In TypeScript For Angular 4+        
const viewArray = [
          {id: 1, question: "Do you feel a connection to a higher source and have a sense of comfort knowing that you are part of something greater than yourself?", category: "Spiritual", subs: []},
          {id: 2, question: "Do you feel you are free of unhealthy behavior that impacts your overall well-being?", category: "Habits", subs: []},
          {id: 3, question: "Do you feel you have healthy and fulfilling relationships?", category: "Relationships", subs: []},
          {id: 4, question: "Do you feel you have a sense of purpose and that you have a positive outlook about yourself and life?", category: "Emotional Well-being", subs: []},
          {id: 5, question: "Do you feel you have a healthy diet and that you are fueling your body for optimal health? ", category: "Eating Habits ", subs: []},
          {id: 6, question: "Do you feel that you get enough rest and that your stress level is healthy?", category: "Relaxation ", subs: []},
          {id: 7, question: "Do you feel you get enough physical activity for optimal health?", category: "Exercise ", subs: []},
          {id: 8, question: "Do you feel you practice self-care and go to the doctor regularly?", category: "Medical Maintenance", subs: []},
          {id: 9, question: "Do you feel satisfied with your income and economic stability?", category: "Financial", subs: []},
          {id: 10, question: "Do you feel you do fun things and laugh enough in your life?", category: "Play", subs: []},
          {id: 11, question: "Do you feel you have a healthy sense of balance in this area of your life?", category: "Work-life Balance", subs: []},
          {id: 12, question: "Do you feel a sense of peace and contentment  in your home? ", category: "Home Environment", subs: []},
          {id: 13, question: "Do you feel that you are challenged and growing as a person?", category: "Intellectual Wellbeing", subs: []},
          {id: 14, question: "Do you feel content with what you see when you look in the mirror?", category: "Self-image", subs: []},
          {id: 15, question: "Do you feel engaged at work and a sense of fulfillment with your job?", category: "Work Satisfaction", subs: []}
    ];

         const arrayObj = any;
         const objectData = any;

          for (let index = 0; index < this.viewArray.length; index++) {
              this.arrayObj = this.viewArray[index];
              this.arrayObj.filter((x) => {
                if (x.id === id) {
                  this.objectData = x;
                }
              });
              console.log('Json Object Data by ID ==> ', this.objectData);
            }
          };

A non well formed numeric value encountered

This is an old question, but there is another subtle way this message can happen. It's explained pretty well here, in the docs.

Imagine this scenerio:

try {
  // code that triggers a pdo exception
} catch (Exception $e) {
  throw new MyCustomExceptionHandler($e);
}

And MyCustomExceptionHandler is defined roughly like:

class MyCustomExceptionHandler extends Exception {
  public function __construct($e) {
    parent::__construct($e->getMessage(), $e->getCode());
  }
}

This will actually trigger a new exception in the custom exception handler because the Exception class is expecting a number for the second parameter in its constructor, but PDOException might have dynamically changed the return type of $e->getCode() to a string.

A workaround for this would be to define you custom exception handler like:

class MyCustomExceptionHandler extends Exception {
  public function __construct($e) {
    parent::__construct($e->getMessage());
    $this->code = $e->getCode();
  }
}

Cannot edit in read-only editor VS Code

If you can't find where to find code runner as said in Ali NoumSali Traore's answer, here's what you got to do:

  1. Go to extensions (Ctrl + Shift + X)
  2. Find code runner and click on the settings icon on bottom right of the code runner
  3. Click configure extensions settings
  4. Find code_runner: Run in terminal
  5. Check "Whether to run code in terminal"

Change the maximum upload file size

Three things you need to check.

upload_max_filesize, memory_limit and post_max_size in the php.ini configuration file exactly.

All of these three settings limit the maximum size of data that can be submitted and handled by PHP.

Typically post_max_size and memory_limit need to be larger than upload_max_filesize.


So three variables total you need to check to be absolutely sure.

How to remove folders with a certain name

find path/to/the/folders -maxdepth 1 -name "my_*" -type d -delete

Make a simple fade in animation in Swift?

Swift 5

Other answers are correct, but in my case I need to handle other properties also (alpha, animate, completion). Because of this, I modified a bit to expose these parameters as below:

extension UIView {
    /// Helper function to update view's alpha with animation
    /// - Parameter alpha: View's alpha
    /// - Parameter animate: Indicate alpha changing with animation or not
    /// - Parameter duration: Indicate time for animation
    /// - Parameter completion: Completion block after alpha changing is finished
    func set(alpha: CGFloat, animate: Bool, duration: TimeInterval = 0.3, completion: ((Bool) -> Void)? = nil) {
        let animation = { (view: UIView) in
            view.alpha = alpha
        }
    
        if animate {
            UIView.animate(withDuration: duration, animations: {
                animation(self)
            }, completion: { finished in
                completion?(finished)
            })
        } else {
            layer.removeAllAnimations()
            animation(self)
            completion?(true)
        }
    }
}

SQL: How to perform string does not equal

Another way of getting the results

SELECT * from table WHERE SUBSTRING(tester, 1, 8)  <> 'username' or tester is null

Multiple scenarios @RequestMapping produces JSON/XML together with Accept or ResponseEntity

Using Accept header is really easy to get the format json or xml from the REST service.

This is my Controller, take a look produces section.

@RequestMapping(value = "properties", produces = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE}, method = RequestMethod.GET)
    public UIProperty getProperties() {
        return uiProperty;
    }

In order to consume the REST service we can use the code below where header can be MediaType.APPLICATION_JSON_VALUE or MediaType.APPLICATION_XML_VALUE

HttpHeaders headers = new HttpHeaders();
headers.add("Accept", header);

HttpEntity entity = new HttpEntity(headers);

RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> response = restTemplate.exchange("http://localhost:8080/properties", HttpMethod.GET, entity,String.class);
return response.getBody();

Edit 01:

In order to work with application/xml, add this dependency

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
</dependency>

jQuery issue in Internet Explorer 8

Correction:

Check your script include tag, is it using

type="application/javascript" src="/path/to/jquery" 

change to

type="text/javascript" src="/path/to/jquery" 

UITapGestureRecognizer - single tap and double tap

Some view have there own double tap recognizers built in (MKMapView being an example). To get around this you will need to implement UIGestureRecognizerDelegate method shouldRecognizeSimultaneouslyWithGestureRecognizer and return YES:

First implement your double and single recognizers:

// setup gesture recognizers
UITapGestureRecognizer* singleTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self
                                                                                action:@selector(mapViewTapped:)];
singleTapRecognizer.delegate = self;
singleTapRecognizer.numberOfTapsRequired = 1;


UITapGestureRecognizer* doubleTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self
                                                                                      action:@selector(mapViewDoubleTapped:)];
doubleTapRecognizer.delegate = self;    // this allows
doubleTapRecognizer.numberOfTapsRequired = 2;
[singleTapRecognizer requireGestureRecognizerToFail:doubleTapRecognizer];

And then implement:

#pragma mark UIGestureRecognizerDelegate
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer
*)otherGestureRecognizer {  return YES; }

How to view query error in PDO PHP

a quick way to see your errors whilst testing:

$error= $st->errorInfo();
echo $error[2];

Is it possible to change the package name of an Android app on Google Play?

As far as I can tell what you could do is "retire" your previous app and redirect all users to your new app. This procedure is not supported by Google (tsk... tsk...), but it could be implemented in four steps:

  1. Change the current application to show a message to the users about the upgrade and redirect them to the new app listing. Probably a full screen message would do with some friendly text. This message could be triggered remotely ideally, but a cut-off date can be used too. (But then that will be a hard deadline for you, so be careful... ;))

  2. Release the modified old app as an upgrade, maybe with some feature upgrades/bug fixes too, to "sweeten the deal" to the users. Still there is no guarantee that all users will upgrade, but probably the majority will do.

  3. Prepare your new app with the updated package name and upload it to the store, then trigger the message in the old app (or just wait until it expires, if that was your choice).

  4. Unpublish the old app in Play Store to avoid any new installs. Unpublishing an app doesn't mean the users who already installed it won't have access to it anymore, but at least the potential new users won't find it on the market.

Not ideal and can be annoying to the users, sometimes even impossible to implement due to the status/possibilities of the app. But since Google left us no choice this is the only way to migrate the users of the old apps to a "new" one (even if it is not really new). Not to mention that if you don't have access to the sources and code signing details for the old app then all you could do is hoping that he users will notice the new app...

If anybody figured out a better way by all means: please do tell.

How to change the default encoding to UTF-8 for Apache?

Place AddDefaultCharset UTF-8 into /etc/apache2/conf.d/charset. In fact, it's already there. You just have to uncomment it by removing the preceding #.

Requery a subform from another form?

I tried several solutions above, but none solved my problem. Solution to refresh a subform in a form after saving data to database:

Me.subformname.Requery

It worked fine for me. Good luck.

How to generate a HTML page dynamically using PHP?

It looks funny but it works.

<?php 
$file = 'newpage.html';
// Open the file to get existing content
$current = file_get_contents($file);
// Append a new person to the file
$current .= "<!doctype html><html>
<head><meta charset='utf-8'>
<title>new file</title>
</head><body><h3>New HTML file</h3>
</body></html>
";
// Write the contents back to the file
file_put_contents($file, $current);
?>

jquery: change the URL address without redirecting?

That site makes use of the "fragment" part of a url: the stuff after the "#". This is not sent to the server by the browser as part of the GET request, but can be used to store page state. So yes you can change the fragment without causing a page refresh or reload. When the page loads, your javascript reads this fragment and updates the page content appropriately, fetching data from the server via ajax requests as required. To read the fragment in js:

var fragment = location.hash;

but note that this value will include the "#" character at the beginning. To set the fragment:

location.hash = "your_state_data";

Set folder browser dialog start location

Set the SelectedPath property before you call ShowDialog ...

folderBrowserDialog1.SelectedPath = @"c:\temp\";
folderBrowserDialog1.ShowDialog();

Will start them at C:\Temp

Regex - how to match everything except a particular pattern

notnot, resurrecting this ancient question because it had a simple solution that wasn't mentioned. (Found your question while doing some research for a regex bounty quest.)

I'm faced with a situation where I have to match an (A and ~B) pattern.

The basic regex for this is frighteningly simple: B|(A)

You just ignore the overall matches and examine the Group 1 captures, which will contain A.

An example (with all the disclaimers about parsing html in regex): A is digits, B is digits within <a tag

The regex: <a.*?<\/a>|(\d+)

Demo (look at Group 1 in the lower right pane)

Reference

How to match pattern except in situations s1, s2, s3

How to match a pattern unless...

How to convert a PIL Image into a numpy array?

Convert Numpy to PIL image and PIL to Numpy

import numpy as np
from PIL import Image

def pilToNumpy(img):
    return np.array(img)

def NumpyToPil(img):
    return Image.fromarray(img)

javac error: Class names are only accepted if annotation processing is explicitly requested

chandan@cmaster:~/More$ javac New.java
chandan@cmaster:~/More$ javac New
error: Class names, 'New', are only accepted if annotation processing is explicitly requested
1 error

So if you by mistake after compiling again use javac for running a program.

jquery onclick change css background image

I think this should be:

$('.home').click(function() {
     $(this).css('background', 'url(images/tabs3.png)');
 });

and remove this:

<div class="home" onclick="function()">
     //-----------^^^^^^^^^^^^^^^^^^^^---------no need for this

You have to make sure you have a correct path to your image.

file path Windows format to java format

Java 7 and up supports the Path class (in java.nio package). You can use this class to convert a string-path to one that works for your current OS.

Using:

Paths.get("\\folder\\subfolder").toString()

on a Unix machine, will give you /folder/subfolder. Also works the other way around.

https://docs.oracle.com/javase/tutorial/essential/io/pathOps.html

What is recursion and when should I use it?

I use recursion. What does that have to do with having a CS degree... (which I don't, by the way)

Common uses I have found:

  1. sitemaps - recurse through filesystem starting at document root
  2. spiders - crawling through a website to find email address, links, etc.
  3. ?

How to perform a for loop on each character in a string in Bash?

I'm surprised no one has mentioned the obvious bash solution utilizing only while and read.

while read -n1 character; do
    echo "$character"
done < <(echo -n "$words")

Note the use of echo -n to avoid the extraneous newline at the end. printf is another good option and may be more suitable for your particular needs. If you want to ignore whitespace then replace "$words" with "${words// /}".

Another option is fold. Please note however that it should never be fed into a for loop. Rather, use a while loop as follows:

while read char; do
    echo "$char"
done < <(fold -w1 <<<"$words")

The primary benefit to using the external fold command (of the coreutils package) would be brevity. You can feed it's output to another command such as xargs (part of the findutils package) as follows:

fold -w1 <<<"$words" | xargs -I% -- echo %

You'll want to replace the echo command used in the example above with the command you'd like to run against each character. Note that xargs will discard whitespace by default. You can use -d '\n' to disable that behavior.


Internationalization

I just tested fold with some of the Asian characters and realized it doesn't have Unicode support. So while it is fine for ASCII needs, it won't work for everyone. In that case there are some alternatives.

I'd probably replace fold -w1 with an awk array:

awk 'BEGIN{FS=""} {for (i=1;i<=NF;i++) print $i}'

Or the grep command mentioned in another answer:

grep -o .


Performance

FYI, I benchmarked the 3 aforementioned options. The first two were fast, nearly tying, with the fold loop slightly faster than the while loop. Unsurprisingly xargs was the slowest... 75x slower.

Here is the (abbreviated) test code:

words=$(python -c 'from string import ascii_letters as l; print(l * 100)')

testrunner(){
    for test in test_while_loop test_fold_loop test_fold_xargs test_awk_loop test_grep_loop; do
        echo "$test"
        (time for (( i=1; i<$((${1:-100} + 1)); i++ )); do "$test"; done >/dev/null) 2>&1 | sed '/^$/d'
        echo
    done
}

testrunner 100

Here are the results:

test_while_loop
real    0m5.821s
user    0m5.322s
sys     0m0.526s

test_fold_loop
real    0m6.051s
user    0m5.260s
sys     0m0.822s

test_fold_xargs
real    7m13.444s
user    0m24.531s
sys     6m44.704s

test_awk_loop
real    0m6.507s
user    0m5.858s
sys     0m0.788s

test_grep_loop
real    0m6.179s
user    0m5.409s
sys     0m0.921s

best practice font size for mobile

The font sizes in your question are an example of what ratio each header should be in comparison to each other, rather than what size they should be themselves (in pixels).

So in response to your question "Is there a 'best practice' for these for mobile phones? - say iphone screen size?", yes there probably is - but you might find what someone says is "best practice" does not work for your layout.

However, to help get you on the right track, this article about building responsive layouts provides a good example of how to calculate the base font-size in pixels in relation to device screen sizes.

The suggested font-sizes for screen resolutions suggested from that article are as follows:

@media (min-width: 858px) {
    html {
        font-size: 12px;
    }
}

@media (min-width: 780px) {
    html {
        font-size: 11px;
    }
}

@media (min-width: 702px) {
    html {
        font-size: 10px;
    }
}

@media (min-width: 724px) {
    html {
        font-size: 9px;
    }
}

@media (max-width: 623px) {
    html {
        font-size: 8px;
    }
}

Github Windows 'Failed to sync this branch'

When it says that, just open the shell and do git status. That will give you a decent idea of what could be wrong and the state of your repo.

I can't give you a specific error for this as it happens for many reasons in Github for Windows, like say some problem in updating submodules etc.

How to execute a file within the python interpreter?

Python 2 + Python 3

exec(open("./path/to/script.py").read(), globals())

This will execute a script and put all it's global variables in the interpreter's global scope (the normal behavior in most scripting environments).

Python 3 exec Documentation

how to make a cell of table hyperlink

Not exactly making the cell a link, but the table itself. I use this as a button in e-mails, giving me div-like controls.

_x000D_
_x000D_
<a href="https://www.foo.bar" target="_blank" style="color: white; font-weight: bolder; text-decoration: none;">
  <table style="margin-left: auto; margin-right: auto;" align="center">
    <tr>
      <td style="padding: 20px; height: 60px;" bgcolor="#00b389">Go to Foo Bar</td>
    </tr>
  </table>
</a>
_x000D_
_x000D_
_x000D_

Javascript - Track mouse position

I believe that we are overthinking this,

_x000D_
_x000D_
function mouse_position(e)_x000D_
{_x000D_
//do stuff_x000D_
}
_x000D_
<body onmousemove="mouse_position(event)"></body>
_x000D_
_x000D_
_x000D_

Simple example of threading in C++

It largely depends on the library you decide to use. For instance, if you use the wxWidgets library, the creation of a thread would look like this:

class RThread : public wxThread {

public:
    RThread()
        : wxThread(wxTHREAD_JOINABLE){
    }
private:
    RThread(const RThread &copy);

public:
    void *Entry(void){
        //Do...

        return 0;
    }

};

wxThread *CreateThread() {
    //Create thread
    wxThread *_hThread = new RThread();

    //Start thread
    _hThread->Create();
    _hThread->Run();

    return _hThread;
}

If your main thread calls the CreateThread method, you'll create a new thread that will start executing the code in your "Entry" method. You'll have to keep a reference to the thread in most cases to join or stop it. More info here: wxThread documentation

How to obtain a QuerySet of all rows, with specific fields for each one of them?

Oskar Persson's answer is the best way to handle it because makes it easier to pass the data to the context and treat it normally from the template as we get the object instances (easily iterable to get props) instead of a plain value list.

After that you can just easily get the wanted prop:

for employee in employees:
    print(employee.eng_name)

Or in the template:

{% for employee in employees %}

    <p>{{ employee.eng_name }}</p>

{% endfor %}

Get folder name of the file in Python

You are looking to use dirname. If you only want that one directory, you can use os.path.basename,

When put all together it looks like this:

os.path.basename(os.path.dirname('dir/sub_dir/other_sub_dir/file_name.txt'))

That should get you "other_sub_dir"

The following is not the ideal approach, but I originally proposed,using os.path.split, and simply get the last item. which would look like this:

os.path.split(os.path.dirname('dir/sub_dir/other_sub_dir/file_name.txt'))[-1]

What is the easiest way to push an element to the beginning of the array?

You can use methodsolver to find Ruby functions.

Here is a small script,

require 'methodsolver'

solve { a = [1,2,3]; a.____(0) == [0,1,2,3] }

Running this prints

Found 1 methods
- Array#unshift

You can install methodsolver using

gem install methodsolver

Heap vs Binary Search Tree (BST)

Another use of BST over Heap; because of an important difference :

  • finding successor and predecessor in a BST will take O(h) time. ( O(logn) in balanced BST)
  • while in Heap, would take O(n) time to find successor or predecessor of some element.

Use of BST over a Heap: Now, Lets say we use a data structure to store landing time of flights. We cannot schedule a flight to land if difference in landing times is less than 'd'. And assume many flights have been scheduled to land in a data structure(BST or Heap).

Now, we want to schedule another Flight which will land at t. Hence, we need to calculate difference of t with its successor and predecessor (should be >d). Thus, we will need a BST for this, which does it fast i.e. in O(logn) if balanced.

EDITed:

Sorting BST takes O(n) time to print elements in sorted order (Inorder traversal), while Heap can do it in O(n logn) time. Heap extracts min element and re-heapifies the array, which makes it do the sorting in O(n logn) time.

How to configure heroku application DNS to Godaddy Domain?

I used this videocast to set up my GoDaddy domain with Heroku, and it worked perfectly. Very clear and well explained.

Note: Skip the part about CNAME yourdomain.com. (note the .) and the heroku addons:add "custom domains"

http://blog.heroku.com/archives/2009/10/7/heroku_casts_setting_up_custom_domains/


To summarize the video:

1) on GoDaddy and create a CNAME with

Alias Name: www
Host Name: proxy.heroku.com

2) check that your domain has propagated by typing host www.yourdomain.com on the command line

3) run heroku domains:add www.yourdomain.com

4) run heroku domains:add yourdomain.com

It worked for me after these steps. Hope it works for you too!

UPDATE: things have changed, check out this post Heroku/GoDaddy: send naked domain to www

Change text color with Javascript?

You set the style per element and not by its content:

function init() { 
  document.getElementById("about").style.color = 'blue';
}

With innerHTML you get/set the content of an element. So if you would want to modify your title, innerHTML would be the way to go.

In your case, however, you just want to modify a property of the element (change the color of the text inside it), so you address the style property of the element itself.

How do Common Names (CN) and Subject Alternative Names (SAN) work together?

This depends on implementation, but the general rule is that the domain is checked against all SANs and the common name. If the domain is found there, then the certificate is ok for connection.

RFC 5280, section 4.1.2.6 says "The subject name MAY be carried in the subject field and/or the subjectAltName extension". This means that the domain name must be checked against both SubjectAltName extension and Subject property (namely it's common name parameter) of the certificate. These two places complement each other, and not duplicate it. And SubjectAltName is a proper place to put additional names, such as www.domain.com or www2.domain.com

Update: as per RFC 6125, published in 2011, the validator must check SAN first, and if SAN exists, then CN should not be checked. Note that RFC 6125 is relatively recent and there still exist certificates and CAs that issue certificates, which include the "main" domain name in CN and alternative domain names in SAN. I.e. by excluding CN from validation if SAN is present, you can deny some otherwise valid certificate.

Number of processors/cores in command line

This is for those who want to a portable way to count cpu cores on *bsd, *nix or solaris (haven't tested on aix and hp-ux but should work). It has always worked for me.

dmesg | \
egrep 'cpu[. ]?[0-9]+' | \
sed 's/^.*\(cpu[. ]*[0-9]*\).*$/\1/g' | \
sort -u | \
wc -l | \
tr -d ' '

solaris grep & egrep don't have -o option so sed is used instead.

Serializing enums with Jackson

In Spring Boot 2, the easiest way is to declare in your application.properties:

spring.jackson.serialization.WRITE_ENUMS_USING_TO_STRING=true
spring.jackson.deserialization.READ_ENUMS_USING_TO_STRING=true

and define the toString() method of your enums.

Android ImageButton with a selected state?

The best way to do this without more images :

public static void buttonEffect(View button){
    button.setOnTouchListener(new OnTouchListener() {

        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN: {
                    v.getBackground().setColorFilter(0xe0f47521,PorterDuff.Mode.SRC_ATOP);
                    v.invalidate();
                    break;
                }
                case MotionEvent.ACTION_UP: {
                    v.getBackground().clearColorFilter();
                    v.invalidate();
                    break;
                }
            }
            return false;
        }
    });
}

MySQL "Or" Condition

Wrap your AND logic in parenthesis, like this:

mysql_query("SELECT * FROM Drinks WHERE email='$Email' AND (date='$Date_Today' OR date='$Date_Yesterday' OR date='$Date_TwoDaysAgo' OR date='$Date_ThreeDaysAgo' OR date='$Date_FourDaysAgo' OR date='$Date_FiveDaysAgo' OR date='$Date_SixDaysAgo' OR date='$Date_SevenDaysAgo')");

How to run Maven from another directory (without cd to project dir)?

I don't think maven supports this. If you're on Unix, and don't want to leave your current directory, you could use a small shell script, a shell function, or just a sub-shell:

user@host ~/project$ (cd ~/some/location; mvn install)
[ ... mvn build ... ]
user@host ~/project$

As a bash function (which you could add to your ~/.bashrc):

function mvn-there() {
  DIR="$1"
  shift
  (cd $DIR; mvn "$@")     
} 

user@host ~/project$ mvn-there ~/some/location install)
[ ... mvn build ... ]
user@host ~/project$

I realize this doesn't answer the specific question, but may provide you with what you're after. I'm not familiar with the Windows shell, though you should be able to reach a similar solution there as well.

Regards

How to convert DataSet to DataTable

A DataSet already contains DataTables. You can just use:

DataTable firstTable = dataSet.Tables[0];

or by name:

DataTable customerTable = dataSet.Tables["Customer"];

Note that you should have using statements for your SQL code, to ensure the connection is disposed properly:

using (SqlConnection conn = ...)
{
    // Code here...
}

Tomcat view catalina.out log file

 cd /usr/local/tomcat/logs
 tail -f catalina.out

Convert String to System.IO.Stream

string str = "asasdkopaksdpoadks";
byte[] data = Encoding.ASCII.GetBytes(str);
MemoryStream stm = new MemoryStream(data, 0, data.Length);

How to enable curl in Wamp server

Left Click on the WAMP icon the system try -> PHP -> PHP Extensions -> Enable php_curl

onKeyPress Vs. onKeyUp and onKeyDown

A few practical facts that might be useful to decide which event to handle (run the script below and focus on the input box):

_x000D_
_x000D_
$('input').on('keyup keydown keypress',e=>console.log(e.type, e.keyCode, e.which, e.key))
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<input/>
_x000D_
_x000D_
_x000D_

Pressing:

  • non inserting/typing keys (e.g. Shift, Ctrl) will not trigger a keypress. Press Ctrl and release it:

    keydown 17 17 Control

    keyup 17 17 Control

  • keys from keyboards that apply characters transformations to other characters may lead to Dead and duplicate "keys" (e.g. ~, ´) on keydown. Press ´ and release it in order to display a double ´´:

    keydown 192 192 Dead

    keydown 192 192 ´´

    keypress 180 180 ´

    keypress 180 180 ´

    keyup 192 192 Dead

Additionally, non typing inputs (e.g. ranged <input type="range">) will still trigger all keyup, keydown and keypress events according to the pressed keys.

setting content between div tags using javascript

See Creating and modifying HTML at what used to be called the Web Standards Curriculum.

Use the createElement, createTextNode and appendChild methods.

Add new item in existing array in c#.net

Unfortunately using a list won't work in all situations. A list and an array are actually different and are not 100% interchangeable. It would depend on the circumstances if this would be an acceptable work around.

Can I try/catch a warning?

FolderStructure

index.php //Script File
logs //Folder for log Every warning and Errors
CustomException.php //Custom exception File

CustomException.php

/**
* Custom error handler
*/
function handleError($code, $description, $file = null, $line = null, $context = null) {
    $displayErrors = ini_get("display_errors");;
    $displayErrors = strtolower($displayErrors);
    if (error_reporting() === 0 || $displayErrors === "on") {
        return false;
    }
    list($error, $log) = mapErrorCode($code);
    $data = array(
        'timestamp' => date("Y-m-d H:i:s:u", time()),
        'level' => $log,
        'code' => $code,
        'type' => $error,
        'description' => $description,
        'file' => $file,
        'line' => $line,
        'context' => $context,
        'path' => $file,
        'message' => $error . ' (' . $code . '): ' . $description . ' in [' . $file . ', line ' . $line . ']'
    );
    $data = array_map('htmlentities',$data);
    return fileLog(json_encode($data));
}

/**
* This method is used to write data in file
* @param mixed $logData
* @param string $fileName
* @return boolean
*/
function fileLog($logData, $fileName = ERROR_LOG_FILE) {
    $fh = fopen($fileName, 'a+');
    if (is_array($logData)) {
        $logData = print_r($logData, 1);
    }
    $status = fwrite($fh, $logData . "\n");
    fclose($fh);
//    $file = file_get_contents($filename);
//    $content = '[' . $file .']';
//    file_put_contents($content); 
    return ($status) ? true : false;
}

/**
* Map an error code into an Error word, and log location.
*
* @param int $code Error code to map
* @return array Array of error word, and log location.
*/
function mapErrorCode($code) {
    $error = $log = null;
    switch ($code) {
        case E_PARSE:
        case E_ERROR:
        case E_CORE_ERROR:
        case E_COMPILE_ERROR:
        case E_USER_ERROR:
            $error = 'Fatal Error';
            $log = LOG_ERR;
            break;
        case E_WARNING:
        case E_USER_WARNING:
        case E_COMPILE_WARNING:
        case E_RECOVERABLE_ERROR:
            $error = 'Warning';
            $log = LOG_WARNING;
            break;
        case E_NOTICE:
        case E_USER_NOTICE:
            $error = 'Notice';
            $log = LOG_NOTICE;
            break;
        case E_STRICT:
            $error = 'Strict';
            $log = LOG_NOTICE;
            break;
        case E_DEPRECATED:
        case E_USER_DEPRECATED:
            $error = 'Deprecated';
            $log = LOG_NOTICE;
            break;
        default :
            break;
    }
    return array($error, $log);
}
//calling custom error handler
set_error_handler("handleError");

just include above file into your script file like this

index.php

error_reporting(E_ALL);
ini_set('display_errors', 'off');
define('ERROR_LOG_FILE', 'logs/app_errors.log');

include_once 'CustomException.php';
echo $a; // here undefined variable warning will be logged into logs/app_errors.log

Paste multiple columns together

library(plyr)

ldply(apply(data, 1, function(x) data.frame(
                      x = paste(x[2:4],sep="",collapse="-"))))

#      x
#1 a-d-g
#2 b-e-h
#3 c-f-i

#  and with just the vector of names you have:

ldply(apply(data, 1, function(x) data.frame(
                      x = paste(x[c('b','c','d')],sep="",collapse="-"))))

# or equally:
mynames <-c('b','c','d')
ldply(apply(data, 1, function(x) data.frame(
                      x = paste(x[mynames],sep="",collapse="-"))))    

How can I save multiple documents concurrently in Mongoose/Node.js?

Bulk inserts in Mongoose can be done with .insert() unless you need to access middleware.

Model.collection.insert(docs, options, callback)

https://github.com/christkv/node-mongodb-native/blob/master/lib/mongodb/collection.js#L71-91

Error in setting JAVA_HOME

The JAVA_HOME should point to the JDK home rather than the JRE home if you are going to be compiling stuff, likewise - I would try and install the JDK in a directory that doesn't include a space. Even if this is not your problem now, it can cause problems in the future!

What should be the sizeof(int) on a 64-bit machine?

Size of a pointer should be 8 byte on any 64-bit C/C++ compiler, but not necessarily size of int.

ffmpeg usage to encode a video to H264 codec format

"C:\Program Files (x86)\ffmpegX86shared\bin\ffmpeg.exe" -y -i "C:\testfile.ts" -an -vcodec libx264 -g 75 -keyint_min 12 -vb 4000k -vprofile high -level 40 -s 1920x1080 -y -threads 0 -r 25 "C:\testfile.h264"

The above worked for me on a Windows machine using a FFmpeg Win32 shared build by Kyle Schwarz. The build was compiled on: Feb 22 2013, at: 01:09:53

Note that -an defines that audio should be skipped.

Timing Delays in VBA

For MS Access: Launch a hidden form with Me.TimerInterval set and a Form_Timer event handler. Put your to-be-delayed code in the Form_Timer routine - exiting the routine after each execution.

E.g.:

Private Sub Form_Load()
    Me.TimerInterval = 30000 ' 30 sec
End Sub

Private Sub Form_Timer()

    Dim lngTimerInterval  As Long: lngTimerInterval = Me.TimerInterval

    Me.TimerInterval = 0

    '<Your Code goes here>

    Me.TimerInterval = lngTimerInterval
End Sub

"Your Code goes here" will be executed 30 seconds after the form is opened and 30 seconds after each subsequent execution.

Close the hidden form when done.

ImportError: Couldn't import Django

I faced the same issue, and in my case it was because I had multiple python versions on my machine, in addition to the Anaconda ones. In my case django didn't worked well with my anaconda python. I knew that when I run import django on each python terminal for all versions I have.

As a summary here are the steps I made to get this solved:

  1. Run the CMD as Admin

  2. Create a project folder.

  3. Create a new ENV for this new project INSIDE THE PROJECT Folder...

    pip install virtualenv >> virtualenv new_env`
    
  4. Activate it:

    .\new_env\Scripts\activate`
    
  5. After the env activation ? Install Django:

    python -m pip install Django
    

The python version you used here in step 5 will determine which python will to work with this installed Django.

Python 3: UnboundLocalError: local variable referenced before assignment

You can fix this by passing parameters rather than relying on Globals

def function(Var1, Var2): 
    if Var2 == 0 and Var1 > 0:
        print("Result One")
    elif Var2 == 1 and Var1 > 0:
        print("Result Two")
    elif Var1 < 1:
        print("Result Three")
    return Var1 - 1
function(1, 1)

Proper Linq where clauses

The first one will be implemented:

Collection.Where(x => x.Age == 10)
          .Where(x => x.Name == "Fido") // applied to the result of the previous
          .Where(x => x.Fat == true)    // applied to the result of the previous

As opposed to the much simpler (and far fasterpresumably faster):

// all in one fell swoop
Collection.Where(x => x.Age == 10 && x.Name == "Fido" && x.Fat == true)

Remove carriage return in Unix

Removing \r on any UNIX® system:

Most existing solutions in this question are GNU-specific, and wouldn't work on OS X or BSD; the solutions below should work on many more UNIX systems, and in any shell, from tcsh to sh, yet still work even on GNU/Linux, too.

Tested on OS X, OpenBSD and NetBSD in tcsh, and on Debian GNU/Linux in bash.


With sed:

In tcsh on an OS X, the following sed snippet could be used together with printf, as neither sed nor echo handle \r in the special way like the GNU does:

sed `printf 's/\r$//g'` input > output

With tr:

Another option is tr:

tr -d '\r' < input > output

Difference between sed and tr:

It would appear that tr preserves a lack of a trailing newline from the input file, whereas sed on OS X and NetBSD (but not on OpenBSD or GNU/Linux) inserts a trailing newline at the very end of the file even if the input is missing any trailing \r or \n at the very end of the file.


Testing:

Here's some sample testing that could be used to ensure this works on your system, using printf and hexdump -C; alternatively, od -c could also be used if your system is missing hexdump:

% printf 'a\r\nb\r\nc' | hexdump -C
00000000  61 0d 0a 62 0d 0a 63                              |a..b..c|
00000007
% printf 'a\r\nb\r\nc' | ( sed `printf 's/\r$//g'` /dev/stdin > /dev/stdout ) | hexdump -C
00000000  61 0a 62 0a 63 0a                                 |a.b.c.|
00000006
% printf 'a\r\nb\r\nc' | ( tr -d '\r' < /dev/stdin > /dev/stdout ) | hexdump -C
00000000  61 0a 62 0a 63                                    |a.b.c|
00000005
% 

stdlib and colored output in C

#include <stdio.h>

#define BLUE(string) "\x1b[34m" string "\x1b[0m"
#define RED(string) "\x1b[31m" string "\x1b[0m"

int main(void)
{
    printf("this is " RED("red") "!\n");

    // a somewhat more complex ...
    printf("this is " BLUE("%s") "!\n","blue");

    return 0;
}

reading Wikipedia:

  • \x1b[0m resets all attributes
  • \x1b[31m sets foreground color to red
  • \x1b[44m would set the background to blue.
  • both : \x1b[31;44m
  • both but inversed : \x1b[31;44;7m
  • remember to reset afterwards \x1b[0m ...

gradient descent using python and numpy

I know this question already have been answer but I have made some update to the GD function :

  ### COST FUNCTION

def cost(theta,X,y):
     ### Evaluate half MSE (Mean square error)
     m = len(y)
     error = np.dot(X,theta) - y
     J = np.sum(error ** 2)/(2*m)
     return J

 cost(theta,X,y)



def GD(X,y,theta,alpha):

    cost_histo = [0]
    theta_histo = [0]

    # an arbitrary gradient, to pass the initial while() check
    delta = [np.repeat(1,len(X))]
    # Initial theta
    old_cost = cost(theta,X,y)

    while (np.max(np.abs(delta)) > 1e-6):
        error = np.dot(X,theta) - y
        delta = np.dot(np.transpose(X),error)/len(y)
        trial_theta = theta - alpha * delta
        trial_cost = cost(trial_theta,X,y)
        while (trial_cost >= old_cost):
            trial_theta = (theta +trial_theta)/2
            trial_cost = cost(trial_theta,X,y)
            cost_histo = cost_histo + trial_cost
            theta_histo = theta_histo +  trial_theta
        old_cost = trial_cost
        theta = trial_theta
    Intercept = theta[0] 
    Slope = theta[1]  
    return [Intercept,Slope]

res = GD(X,y,theta,alpha)

This function reduce the alpha over the iteration making the function too converge faster see Estimating linear regression with Gradient Descent (Steepest Descent) for an example in R. I apply the same logic but in Python.

How do I get the APK of an installed app without root access?

On Nougat(7.0) Android version run adb shell pm list packages to list the packages installed on the device. Then run adb shell pm path your-package-name to show the path of the apk. After use adb to copy the package to Downloads adb shell cp /data/app/com.test-1/base.apk /storage/emulated/0/Download. Then pull the apk from Downloads to your machine by running adb pull /storage/emulated/0/Download/base.apk.

Extract digits from a string in Java

You can use regex and delete non-digits.

str = str.replaceAll("\\D+","");

How to create a template function within a class? (C++)

See here: Templates, template methods,Member Templates, Member Function Templates

class   Vector
{
  int     array[3];

  template <class TVECTOR2> 
  void  eqAdd(TVECTOR2 v2);
};

template <class TVECTOR2>
void    Vector::eqAdd(TVECTOR2 a2)
{
  for (int i(0); i < 3; ++i) array[i] += a2[i];
}

unable to start mongodb local server

if you are running mongo for first time you might wanna set the path first

mongod --dbpath <path to the directory>

Python Pandas Replacing Header with Top Row

Here's a simple trick that defines column indices "in place". Because set_index sets row indices in place, we can do the same thing for columns by transposing the data frame, setting the index, and transposing it back:

df = df.T.set_index(0).T

Note you may have to change the 0 in set_index(0) if your rows have a different index already.

How to write DataFrame to postgres table?

Pandas 0.24.0+ solution

In Pandas 0.24.0 a new feature was introduced specifically designed for fast writes to Postgres. You can learn more about it here: https://pandas.pydata.org/pandas-docs/stable/user_guide/io.html#io-sql-method

import csv
from io import StringIO

from sqlalchemy import create_engine

def psql_insert_copy(table, conn, keys, data_iter):
    # gets a DBAPI connection that can provide a cursor
    dbapi_conn = conn.connection
    with dbapi_conn.cursor() as cur:
        s_buf = StringIO()
        writer = csv.writer(s_buf)
        writer.writerows(data_iter)
        s_buf.seek(0)

        columns = ', '.join('"{}"'.format(k) for k in keys)
        if table.schema:
            table_name = '{}.{}'.format(table.schema, table.name)
        else:
            table_name = table.name

        sql = 'COPY {} ({}) FROM STDIN WITH CSV'.format(
            table_name, columns)
        cur.copy_expert(sql=sql, file=s_buf)

engine = create_engine('postgresql://myusername:mypassword@myhost:5432/mydatabase')
df.to_sql('table_name', engine, method=psql_insert_copy)

Custom bullet symbol for <li> elements in <ul> that is a regular character, and not an image

This is a late answer, but I just came across this... To get the indenting correct on any lines that wrap, try it this way:

ul {
  list-style: none;
  margin-left: 0;
  padding-left: 0;
}

li {
  padding-left: 1em;
  text-indent: -1em;
}

li:before {
  content: "+";
  padding-right: 5px;
}