Programs & Examples On #Href

Hyperlink (or link) is a reference to a document that the reader can directly follow, or that is followed automatically.

How can I change image source on click with jQuery?

You can use jQuery's attr() function, like $("#id").attr('src',"source").

How to redirect to a route in laravel 5 by using href tag if I'm not using blade or any template?

In you app config file change the url to localhost/example/public

Then when you want to link to something

<a href="{{ url('page') }}">Some Text</a>

without blade

<a href="<?php echo url('page') ?>">Some Text</a>

ASP MVC href to a controller/view

Here '~' refers to the root directory ,where Home is controller and Download_Excel_File is actionmethod

 <a href="~/Home/Download_Excel_File" />

The right way of setting <a href=""> when it's a local file

Try swapping your colon : for a bar |. that should do it

<a href="file://C|/path/to/file/file.html">Link Anchor</a>

href="tel:" and mobile numbers

The BlackBerry browser and Safari for iOS (iPhone/iPod/iPad) automatically detect phone numbers and email addresses and convert them to links. If you don’t want this feature, you should use the following meta tags.

For Safari:

<meta name="format-detection" content="telephone=no">

For BlackBerry:

<meta http-equiv="x-rim-auto-match" content="none">

Source: mobilexweb.com

jQuery hyperlinks - href value?

Those "anchors" that exist solely to provide a click event, but do not actually link to other content, should really be button elements because that's what they really are.

It can be styled like so:

<button style="border:none; background:transparent; cursor: pointer;">Click me</button>

And of course click events can be attached to buttons without worry of the browser jumping to the top, and without adding extraneous javascript such as onclick="return false;" or event.preventDefault() .

Html- how to disable <a href>?

<script>
    $(document).ready(function(){
        $('#connectBtn').click(function(e){
            e.preventDefault();
        })
    });
</script>

This will prevent the default action.

jQuery: go to URL with target="_blank"

Detect if a target attribute was used and contains "_blank". For mobile devices that don't like "_blank", this is a reliable alternative.

    $('.someSelector').bind('touchend click', function() {

        var url = $('a', this).prop('href');
        var target = $('a', this).prop('target');

        if(url) {
            // # open in new window if "_blank" used
            if(target == '_blank') { 
                window.open(url, target);
            } else {
                window.location = url;
            }
        }           
    });

href image link download on click

<a href="download.php?file=path/<?=$row['file_name']?>">Download</a>

download.php:

<?php

$file = $_GET['file'];

download_file($file);

function download_file( $fullPath ){

  // Must be fresh start
  if( headers_sent() )
    die('Headers Sent');

  // Required for some browsers
  if(ini_get('zlib.output_compression'))
    ini_set('zlib.output_compression', 'Off');

  // File Exists?
  if( file_exists($fullPath) ){

    // Parse Info / Get Extension
    $fsize = filesize($fullPath);
    $path_parts = pathinfo($fullPath);
    $ext = strtolower($path_parts["extension"]);

    // Determine Content Type
    switch ($ext) {
      case "pdf": $ctype="application/pdf"; break;
      case "exe": $ctype="application/octet-stream"; break;
      case "zip": $ctype="application/zip"; break;
      case "doc": $ctype="application/msword"; break;
      case "xls": $ctype="application/vnd.ms-excel"; break;
      case "ppt": $ctype="application/vnd.ms-powerpoint"; break;
      case "gif": $ctype="image/gif"; break;
      case "png": $ctype="image/png"; break;
      case "jpeg":
      case "jpg": $ctype="image/jpg"; break;
      default: $ctype="application/force-download";
    }

    header("Pragma: public"); // required
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: private",false); // required for certain browsers
    header("Content-Type: $ctype");
    header("Content-Disposition: attachment; filename=\"".basename($fullPath)."\";" );
    header("Content-Transfer-Encoding: binary");
    header("Content-Length: ".$fsize);
    ob_clean();
    flush();
    readfile( $fullPath );

  } else
    die('File Not Found');

}
?>

How to disable anchor "jump" when loading a page?

  1. Browser jumps to <element id="abc" /> if there are http://site.com/#abc hash in the address and the element with id="abc" is visible. So, you just should hide the element by default: <element id="anchor" style="display: none" />. If there is no visible element with id=hash at the page, the browser would not jump.

  2. Create a script that checks the hash in url, and then finds and shows the prrpopriate element (that is hidden by default).

  3. Disable default "hash-like link" behaviour by binding an onclick event to a link and specify return false; as a result of onclick event.

When I implemented tabs, I wrote something like that:

    <script>
    $(function () {         
        if (location.hash != "") {
            selectPersonalTab(location.hash);
        }
        else {
            selectPersonalTab("#cards");
        }
    });

    function selectPersonalTab(hash) {
        $("#personal li").removeClass("active");
        $("a[href$=" + hash + "]").closest("li").addClass("active");
        $("#personaldata > div").hide();
        location.hash = hash;
        $(hash).show();
    }

    $("#personal li a").click(function (e) {
        var t = e.target;
        if (t.href.indexOf("#") != -1) {
            var hash = t.href.substr(t.href.indexOf("#"));
            selectPersonalTab(hash);
            return false;
        }
    });
</script>

Is an empty href valid?

As others have said, it is valid.

There are some downsides to each approach though:

href="#" adds an extra entry to the browser history (which is annoying when e.g. back-buttoning).

href="" reloads the page

href="javascript:;" does not seem to have any problems (other than looking messy and meaningless) - anyone know of any?

Add php variable inside echo statement as href link address?

you can either use

echo '<a href="'.$link_address.'">Link</a>';

or

echo "<a href=\"$link_address\">Link</a>';

if you use double quotes you can insert the variable into the string and it will be parsed.

How to add a href link in PHP?

Just do it in HTML

<a href="https://www.google.com">Google</a>

Removing underline with href attribute

Add a style with the attribute text-decoration:none;:

There are a number of different ways of doing this.

Inline style:

<a href="xxx.html" style="text-decoration:none;">goto this link</a>

Inline stylesheet:

<html>
<head>
<style type="text/css">
   a {
      text-decoration:none;
   }
</style>
</head>
<body>
<a href="xxx.html">goto this link</a>
</body>
</html>

External stylesheet:

<html>
<head>
<link rel="Stylesheet" href="stylesheet.css" />
</head>
<body>
<a href="xxx.html">goto this link</a>
</body>
</html>

stylesheet.css:

a {
      text-decoration:none;
   }

Insert php variable in a href

Try using printf function or the concatination operator

http://php.net/manual/en/function.printf.php

Open link in new tab or window

You can simply do that by setting target="_blank", w3schools has an example.

how to make a cell of table hyperlink

Try this way:

<td><a href="..." style="display:block;">&nbsp;</a></td>

How to change href of <a> tag on button click through javascript

Exactly what Nick Carver did there but I think it would be best if used the DOM setAttribute method.

<script type="text/javascript">
   document.getElementById("myLink").onclick = function() {
   var link = document.getElementById("abc");
   link.setAttribute("href", "xyz.php");
   return false;
   }
</script>

It's one extra line of code but find it better structure-wise.

Get href attribute on jQuery

Use this:

$(function(){
    $("tr.b_row").each(function(){
    var a_href = $(this).find('div.cpt h2 a').attr('href');
    alert ("Href is: "+a_href);

    });
});

See a working demo: http://jsfiddle.net/usmanhalalit/4Ea4k/1/

What does <a href="#" class="view"> mean?

It probably works with Javascript. When you click the link, nothing happens because it points to the current site. The javascript will then load a window or an url. It's used a lot in AJAX web apps.

File URL "Not allowed to load local resource" in the Internet Browser

I didn't realise from your original question that you were opening a file on the local machine, I thought you were sending a file from the web server to the client.

Based on your screenshot, try formatting your link like so:

<a href="file:///C:/Projecten/Protocollen/346/Uitvoeringsoverzicht.xls">Klik hier</a>

(without knowing the contents of each of your recordset variables I can't give you the exact ASP code)

Which "href" value should I use for JavaScript links, "#" or "javascript:void(0)"?

When I've got several faux-links, I prefer to give them a class of 'no-link'.

Then in jQuery, I add the following code:

$(function(){
   $('.no-link').click(function(e){
       e.preventDefault();
   });
});

And for the HTML, the link is simply

<a href="/" class="no-link">Faux-Link</a>

I don't like using Hash-Tags unless they're used for anchors, and I only do the above when I've got more than two faux-links, otherwise I go with javascript:void(0).

<a href="javascript:void(0)" class="no-link">Faux-Link</a>

Typically, I like to just avoid using a link at all and just wrap something around in a span and use that as a way to active some JavaScript code, like a pop-up or a content-reveal.

Remove ALL styling/formatting from hyperlinks

You can simply define a style for links, which would override a:hover, a:visited etc.:

a {
  color: blue;
  text-decoration: none; /* no underline */
}

You can also use the inherit value if you want to use attributes from parent styles instead:

body {
  color: blue;
}
a {
  color: inherit; /* blue colors for links too */
  text-decoration: inherit; /* no underline */
}

How To Add An "a href" Link To A "div"?

Your solutions don't seem to be working for me, I have the following code. How to put link into the last two divs.

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office">

<style>
/* Import */
@import url(https://fonts.googleapis.com/css?family=Quicksand:300,400);
* {
  font-family: "Quicksand", sans-serif; 
  font-weight: bold; 
  text-align: center;  
  text-transform: uppercase; 
  -webkit-transition: all 0.25s ease; 
  -moz-transition: all 0.25s ease; 
  -ms-transition: all 0.25s ease; 
  -o-transition: all 0.025s ease; 
}

/* Colors */

#ora {
  background-color: #e67e22; 
}

#red {
  background-color: #e74c3c; 
}

#orab {
  background-color: white; 
  border: 5px solid #e67e22; 
}

#redb {
  background-color: white; 
  border: 5px solid #e74c3c; 
}
/* End of Colors */

.B {
  width: 240px; 
  height: 55px; 
  margin: auto; 
  line-height: 45px; 
  display: inline-block; 
  box-sizing: border-box; 
  -webkit-box-sizing: border-box; 
  -moz-box-sizing: border-box; 
  -ms-box-sizing: border-box; 
  -o-box-sizing: border-box; 
} 

#orab:hover {
  background-color: #e67e22; 
}

#redb:hover {
  background-color: #e74c3c; 
}
#whib:hover {
  background-color: #ecf0f1; 
}

/* End of Border

.invert:hover {
  -webkit-filter: invert(1);
  -moz-filter: invert(1);
  -ms-filter: invert(1);
  -o-filter: invert(1);
}
</style>
<h1>Flat and Modern Buttons</h1>
<h2>Border Stylin'</h2> 

<div class="B bo" id="orab">See the movies list</div></a>
<div class="B bo" id="redb">Avail a free rental day</div>

</html>

How can I get href links from HTML using Python?

This answer is similar to others with requests and BeautifulSoup, but using list comprehension.

Because find_all() is the most popular method in the Beautiful Soup search API, you can use soup("a") as a shortcut of soup.findAll("a") and using list comprehension:

import requests
from bs4 import BeautifulSoup

URL = "http://www.yourwebsite.com"
page = requests.get(URL)
soup = BeautifulSoup(page.content, features='lxml')
# Find links
all_links = [link.get("href") for link in soup("a")]
# Only external links
ext_links = [link.get("href") for link in soup("a") if "http" in link.get("href")]

https://www.crummy.com/software/BeautifulSoup/bs4/doc/#calling-a-tag-is-like-calling-find-all

href="file://" doesn't work

Although the ffile:////.exe used to work (for example - some versions of early html 4) it appears html 5 disallows this. Tested using the following:

<a href="ffile:///<path name>/<filename>.exe" TestLink /a> 
<a href="ffile://<path name>/<filename>.exe" TestLink /a> 
<a href="ffile:/<path name>/<filename>.exe" TestLink /a> 
<a href="ffile:<path name>/<filename>.exe" TestLink /a> 
<a href="ffile://///<path name>/<filename>.exe" TestLink /a> 
<a href="file://<path name>/<filename>.exe" TestLink /a> 
<a href="file:/<path name>/<filename>.exe" TestLink /a> 
<a href="file:<path name>/<filename>.exe" TestLink /a> 
<a href="ffile://///<path name>/<filename>.exe" TestLink /a>

as well as ... 1/ substituted the "ffile" with just "file" 2/ all the above variations with the http:// prefixed before the ffile or file.

The best I could see was there is a possibility that if one wanted to open (edit) or save the file, it could be accomplished. However, the exec file would not execute otherwise.

HTML tag <a> want to add both href and onclick working

Use jQuery. You need to capture the click event and then go on to the website.

_x000D_
_x000D_
$("#myHref").on('click', function() {_x000D_
  alert("inside onclick");_x000D_
  window.location = "http://www.google.com";_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<a href="#" id="myHref">Click me</a>
_x000D_
_x000D_
_x000D_

How can I disable the bootstrap hover color for links?

I am not a Bootstrap expert, but it sounds to me that you should define a new class called nohover (or something equivalent) then in your link code add the class as the last attribute value:

<a class="green nohover" href="#">green text</a>
<a class="yellow nohover" href="#">yellow text</a>

Then in your Bootstrap LESS/CSS file, define nohover (using the JSFiddle example above):

a:hover { color: red  }
/* Green */
a.green  { color: green; }
/* Yellow */
a.yellow  { color: yellow; }
a.nohover:hover { color: none;  }

Forked the JSFiddle here: http://jsfiddle.net/9rpkq/

window.location.href and window.open () methods in JavaScript

window.open () will open a new window, whereas window.location.href will open the new URL in your current window.

Get local href value from anchor (a) tag

The href property sets or returns the value of the href attribute of a link.

  var hello = domains[i].getElementsByTagName('a')[0].getAttribute('href');
    var url="https://www.google.com/";
    console.log( url+hello);

How to write the code for the back button?

<input type="submit" <a href="#" onclick="history.back();">"Back"</a>

Is invalid HTML due to the unclosed input element.

<a href="#" onclick="history.back(1);">"Back"</a>

is enough

Open URL in same window and in same tab

You can do

window.close();
window.open("index.html");

and it worked successfully on my website.

JavaScript function in href vs. onclick

bad:

<a id="myLink" href="javascript:MyFunction();">link text</a>

good:

<a id="myLink" href="#" onclick="MyFunction();">link text</a>

better:

<a id="myLink" href="#" onclick="MyFunction();return false;">link text</a>

even better 1:

<a id="myLink" title="Click to do something"
 href="#" onclick="MyFunction();return false;">link text</a>

even better 2:

<a id="myLink" title="Click to do something"
 href="PleaseEnableJavascript.html" onclick="MyFunction();return false;">link text</a>

Why better? because return false will prevent browser from following the link

best:

Use jQuery or other similar framework to attach onclick handler by element's ID.

$('#myLink').click(function(){ MyFunction(); return false; });

Select <a> which href ends with some string

$('a[href$="ABC"]:first').attr('title');

This will return the title of the first link that has a URL which ends with "ABC".

How can I disable HREF if onclick is executed?

I solved a situation where I needed a template for the element that would handle alternatively a regular URL or a javascript call, where the js function needs a reference to the calling element. In javascript, "this" works as a self reference only in the context of a form element, e.g., a button. I didn't want a button, just the apperance of a regular link.

Examples:

<a onclick="http://blahblah" href="http://blahblah" target="_blank">A regular link</a>
<a onclick="javascript:myFunc($(this));return false" href="javascript:myFunc($(this));"  target="_blank">javascript with self reference</a>

The href and onClick attributes have the same values, exept I append "return false" on onClick when it's a javascript call. Having "return false" in the called function did not work.

How can I open two pages from a single click without using JavaScript?

If you have the authority to edit the pages to be opened, you can href to 'A' page and in the A page you can put link to B page in onpageload attribute of body tag.

anchor jumping by using javascript

Not enough rep for a comment.

The getElementById() based method in the selected answer won't work if the anchor has name but not id set (which is not recommended, but does happen in the wild).

Something to bare in mind if you don't have control of the document markup (e.g. webextension).

The location based method in the selected answer can also be simplified with location.replace:

function jump(hash) { location.replace("#" + hash) }

Angular 2 router no base href set

it is just that add below code in the index.html head tag

   <html>
    <head>
     <base href="/">
      ...

that worked like a charm for me.

How to remove "href" with Jquery?

If you remove the href attribute the anchor will be not focusable and it will look like simple text, but it will still be clickable.

How to determine the IP address of a Solaris system

There's also:

getent $HOSTNAME

or possibly:

getent `uname -n`

On Solaris 11 the ifconfig command is considered legacy and is being replaced by ipadm

ipadm show-addr

will show the IP addresses on the system for Solaris 11 and later.

NSString with \n or line break

In Swift 3, its much simpler

let stringA = "Terms and Conditions"
let stringB = "Please read the instructions"

yourlabel.text =  "\(stringA)\n\(stringB)"

or if you are using a textView

yourtextView.text =  "\(stringA)\n\(stringB)"

Using the "With Clause" SQL Server 2008

There are two types of WITH clauses:

Here is the FizzBuzz in SQL form, using a WITH common table expression (CTE).

;WITH mil AS (
 SELECT TOP 1000000 ROW_NUMBER() OVER ( ORDER BY c.column_id ) [n]
 FROM master.sys.all_columns as c
 CROSS JOIN master.sys.all_columns as c2
)                
 SELECT CASE WHEN n  % 3 = 0 THEN
             CASE WHEN n  % 5 = 0 THEN 'FizzBuzz' ELSE 'Fizz' END
        WHEN n % 5 = 0 THEN 'Buzz'
        ELSE CAST(n AS char(6))
     END + CHAR(13)
 FROM mil

Here is a select statement also using a WITH clause

SELECT * FROM orders WITH (NOLOCK) where order_id = 123

Is an entity body allowed for an HTTP DELETE request?

Just a heads up, if you supply a body in your DELETE request and are using a google cloud HTTPS load balancer, it will reject your request with a 400 error. I was banging my head against a wall and came to found out that Google, for whatever reason, thinks a DELETE request with a body is a malformed request.

Cross domain POST request is not sending cookie Ajax Jquery

I had this same problem. The session ID is sent in a cookie, but since the request is cross-domain, the browser's security settings will block the cookie from being sent.

Solution: Generate the session ID on the client (in the browser), use Javascript sessionStorage to store the session ID then send the session ID with each request to the server.

I struggled a lot with this issue, and there weren't many good answers around. Here's an article detailing the solution: Javascript Cross-Domain Request With Session

Calling a Javascript Function from Console

An example of where the console will return ReferenceError is putting a function inside a JQuery document ready function

//this will fail
$(document).ready(function () {
          myFunction(alert('doing something!'));
          //other stuff
}

To succeed move the function outside the document ready function

//this will work
myFunction(alert('doing something!'));
$(document).ready(function () {

          //other stuff
}

Then in the console window, type the function name with the '()' to execute the function

myFunction()

Also of use is being able to print out the function body to remind yourself what the function does. Do this by leaving off the '()' from the function name

function myFunction(alert('doing something!'))

Of course if you need the function to be registered after the document is loaded then you couldn't do this. But you might be able to work around that.

Maven: How to run a .java file from command line passing arguments

You could run: mvn exec:exec -Dexec.args="arg1".

This will pass the argument arg1 to your program.

You should specify the main class fully qualified, for example, a Main.java that is in a package test would need

mvn exec:java  -Dexec.mainClass=test.Main

By using the -f parameter, as decribed here, you can also run it from other directories.

mvn exec:java -Dexec.mainClass=test.Main -f folder/pom.xm

For multiple arguments, simply separate them with a space as you would at the command line.

mvn exec:java -Dexec.mainClass=test.Main -Dexec.args="arg1 arg2 arg3"

For arguments separated with a space, you can group using 'argument separated with space' inside the quotation marks.

mvn exec:java -Dexec.mainClass=test.Main -Dexec.args="'argument separated with space' 'another one'"

String Array object in Java

public static void main(String[] args) {

        public String[] name = {"Art", "Dan", "Jen"};
        public String[] country = {"Canada", "Germant", "USA"};
        // initialize your performance array here too.

        //Your constructor takes arrays as an argument so you need to be sure to pass in the arrays and not just objects.
        Athlete art = new Athlete(name, country, performance);   

}

How to save a list to a file and read it as a list type?

I decided I didn't want to use a pickle because I wanted to be able to open the text file and change its contents easily during testing. Therefore, I did this:

score = [1,2,3,4,5]

with open("file.txt", "w") as f:
    for s in score:
        f.write(str(s) +"\n")
score = []
with open("file.txt", "r") as f:
  for line in f:
    score.append(int(line.strip()))

So the items in the file are read as integers, despite being stored to the file as strings.

How to change a PG column to NULLABLE TRUE?

From the fine manual:

ALTER TABLE mytable ALTER COLUMN mycolumn DROP NOT NULL;

There's no need to specify the type when you're just changing the nullability.

Should have subtitle controller already set Mediaplayer error Android

A developer recently added subtitle support to VideoView.

When the MediaPlayer starts playing a music (or other source), it checks if there is a SubtitleController and shows this message if it's not set. It doesn't seem to care about if the source you want to play is a music or video. Not sure why he did that.

Short answer: Don't care about this "Exception".


Edit :

Still present in Lollipop,

If MediaPlayer is only used to play audio files and you really want to remove these errors in the logcat, the code bellow set an empty SubtitleController to the MediaPlayer.

It should not be used in production environment and may have some side effects.

static MediaPlayer getMediaPlayer(Context context){

    MediaPlayer mediaplayer = new MediaPlayer();

    if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.KITKAT) {
        return mediaplayer;
    }

    try {
        Class<?> cMediaTimeProvider = Class.forName( "android.media.MediaTimeProvider" );
        Class<?> cSubtitleController = Class.forName( "android.media.SubtitleController" );
        Class<?> iSubtitleControllerAnchor = Class.forName( "android.media.SubtitleController$Anchor" );
        Class<?> iSubtitleControllerListener = Class.forName( "android.media.SubtitleController$Listener" );

        Constructor constructor = cSubtitleController.getConstructor(new Class[]{Context.class, cMediaTimeProvider, iSubtitleControllerListener});

        Object subtitleInstance = constructor.newInstance(context, null, null);

        Field f = cSubtitleController.getDeclaredField("mHandler");

        f.setAccessible(true);
        try {
            f.set(subtitleInstance, new Handler());
        }
        catch (IllegalAccessException e) {return mediaplayer;}
        finally {
            f.setAccessible(false);
        }

        Method setsubtitleanchor = mediaplayer.getClass().getMethod("setSubtitleAnchor", cSubtitleController, iSubtitleControllerAnchor);

        setsubtitleanchor.invoke(mediaplayer, subtitleInstance, null);
        //Log.e("", "subtitle is setted :p");
    } catch (Exception e) {}

    return mediaplayer;
}

This code is trying to do the following from the hidden API

SubtitleController sc = new SubtitleController(context, null, null);
sc.mHandler = new Handler();
mediaplayer.setSubtitleAnchor(sc, null)

Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.10:test

This error occurs if some unit test cases are failing.

In my application, certain unit tests were not compatible with Java 8 so they were failing. My error was resolved after changing jdk1.8.0_92 to jdk1.7.0_80.

The build would succeed with mvn clean install -DskipTests but this will skip the unit tests. So just ensure that you run then separately after the build is complete.

CRC32 C or C++ implementation

pycrc is a Python script that generates C CRC code, with options to select the CRC size, algorithm and model.

It's released under the MIT licence. Is that acceptable for your purposes?

How can I add an image file into json object?

public class UploadToServer extends Activity {

TextView messageText;
Button uploadButton;
int serverResponseCode = 0;
ProgressDialog dialog = null;

String upLoadServerUri = null;

/********** File Path *************/
final String uploadFilePath = "/mnt/sdcard/";
final String uploadFileName = "Quotes.jpg";

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_upload_to_server);

    uploadButton = (Button) findViewById(R.id.uploadButton);
    messageText = (TextView) findViewById(R.id.messageText);

    messageText.setText("Uploading file path :- '/mnt/sdcard/"
            + uploadFileName + "'");

    /************* Php script path ****************/
    upLoadServerUri = "http://192.1.1.11/hhhh/UploadToServer.php";

    uploadButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {

            dialog = ProgressDialog.show(UploadToServer.this, "",
                    "Uploading file...", true);

            new Thread(new Runnable() {
                public void run() {
                    runOnUiThread(new Runnable() {
                        public void run() {
                            messageText.setText("uploading started.....");
                        }
                    });

                    uploadFile(uploadFilePath + "" + uploadFileName);

                }
            }).start();
        }
    });
}

public int uploadFile(String sourceFileUri) {

    String fileName = sourceFileUri;

    HttpURLConnection connection = null;
    DataOutputStream dos = null;
    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "*****";
    int bytesRead, bytesAvailable, bufferSize;
    byte[] buffer;
    int maxBufferSize = 1 * 1024 * 1024;
    File sourceFile = new File(sourceFileUri);

    if (!sourceFile.isFile()) {

        dialog.dismiss();

        Log.e("uploadFile", "Source File not exist :" + uploadFilePath + ""
                + uploadFileName);

        runOnUiThread(new Runnable() {
            public void run() {
                messageText.setText("Source File not exist :"
                        + uploadFilePath + "" + uploadFileName);
            }
        });

        return 0;

    } else {
        try {

            // open a URL connection to the Servlet
            FileInputStream fileInputStream = new FileInputStream(
                    sourceFile);
            URL url = new URL(upLoadServerUri);

            // Open a HTTP connection to the URL
            connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput(true); // Allow Inputs
            connection.setDoOutput(true); // Allow Outputs
            connection.setUseCaches(false); // Don't use a Cached Copy
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Connection", "Keep-Alive");
            connection.setRequestProperty("ENCTYPE", "multipart/form-data");
            connection.setRequestProperty("Content-Type",
                    "multipart/form-data;boundary=" + boundary);
            connection.setRequestProperty("uploaded_file", fileName);

            dos = new DataOutputStream(connection.getOutputStream());

            dos.writeBytes(twoHyphens + boundary + lineEnd);
            // dos.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
            // + fileName + "\"" + lineEnd);
            dos.writeBytes("Content-Disposition: post-data; name=uploadedfile;filename="
                    + URLEncoder.encode(fileName, "UTF-8") + lineEnd);

            dos.writeBytes(lineEnd);

            // create a buffer of maximum size
            bytesAvailable = fileInputStream.available();

            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            buffer = new byte[bufferSize];

            // read file and write it into form...
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);

            while (bytesRead > 0) {

                dos.write(buffer, 0, bufferSize);
                bytesAvailable = fileInputStream.available();
                bufferSize = Math.min(bytesAvailable, maxBufferSize);
                bytesRead = fileInputStream.read(buffer, 0, bufferSize);

            }

            // send multipart form data necesssary after file data...
            dos.writeBytes(lineEnd);
            dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

            // Responses from the server (code and message)
            int serverResponseCode = connection.getResponseCode();
            String serverResponseMessage = connection.getResponseMessage();

            Log.i("uploadFile", "HTTP Response is : "
                    + serverResponseMessage + ": " + serverResponseCode);

            if (serverResponseCode == 200) {

                runOnUiThread(new Runnable() {
                    public void run() {

                        String msg = "File Upload Completed.\n\n See uploaded file here : \n\n"
                                + " http://www.androidexample.com/media/uploads/"
                                + uploadFileName;

                        messageText.setText(msg);
                        Toast.makeText(UploadToServer.this,
                                "File Upload Complete.", Toast.LENGTH_SHORT)
                                .show();
                    }
                });
            }

            // close the streams //
            fileInputStream.close();
            dos.flush();
            dos.close();

        } catch (MalformedURLException ex) {

            dialog.dismiss();
            ex.printStackTrace();

            runOnUiThread(new Runnable() {
                public void run() {
                    messageText
                            .setText("MalformedURLException Exception : check script url.");
                    Toast.makeText(UploadToServer.this,
                            "MalformedURLException", Toast.LENGTH_SHORT)
                            .show();
                }
            });

            Log.e("Upload file to server", "error: " + ex.getMessage(), ex);
        } catch (Exception e) {

            dialog.dismiss();
            e.printStackTrace();

            runOnUiThread(new Runnable() {
                public void run() {
                    messageText.setText("Got Exception : see logcat ");
                    Toast.makeText(UploadToServer.this,
                            "Got Exception : see logcat ",
                            Toast.LENGTH_SHORT).show();
                }
            });
            Log.e("Upload file to server Exception",
                    "Exception : " + e.getMessage(), e);
        }
        dialog.dismiss();
        return serverResponseCode;

    } // End else block
}

PHP FILE

<?php
$target_path  = "./Upload/";
$target_path = $target_path . basename( $_FILES['uploadedfile']['name']);
if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {
echo "The file ".  basename( $_FILES['uploadedfile']['name']).
" has been uploaded";
} else{
 echo "There was an error uploading the file, please try again!";
}
?>

The equivalent of a GOTO in python

Gotos are universally reviled in computer science and programming as they lead to very unstructured code.

Python (like almost every programming language today) supports structured programming which controls flow using if/then/else, loop and subroutines.

The key to thinking in a structured way is to understand how and why you are branching on code.

For example, lets pretend Python had a goto and corresponding label statement shudder. Look at the following code. In it if a number is greater than or equal to 0 we print if it

number = input()
if number < 0: goto negative
if number % 2 == 0:
   print "even"
else:
   print "odd"
goto end
label: negative
print "negative"
label: end
print "all done"

If we want to know when a piece of code is executed, we need to carefully traceback in the program, and examine how a label was arrived at - which is something that can't really be done.

For example, we can rewrite the above as:

number = input()
goto check

label: negative
print "negative"
goto end

label: check
if number < 0: goto negative
if number % 2 == 0:
   print "even"
else:
   print "odd"
goto end

label: end
print "all done"

Here, there are two possible ways to arrive at the "end", and we can't know which one was chosen. As programs get large this kind of problem gets worse and results in spaghetti code

In comparison, below is how you would write this program in Python:

number = input()
if number >= 0:
   if number % 2 == 0:
       print "even"
   else:
       print "odd"
else:
   print "negative"
print "all done"

I can look at a particular line of code, and know under what conditions it is met by tracing back the tree of if/then/else blocks it is in. For example, I know that the line print "odd" will be run when a ((number >= 0) == True) and ((number % 2 == 0) == False).

Calling a function within a Class method?

Try this one:

class test {
     public function newTest(){
          $this->bigTest();
          $this->smallTest();
     }

     private function bigTest(){
          //Big Test Here
     }

     private function smallTest(){
          //Small Test Here
     }

     public function scoreTest(){
          //Scoring code here;
     }
}

$testObject = new test();

$testObject->newTest();

$testObject->scoreTest();

how to convert a string date to date format in oracle10g

You can convert a string to a DATE using the TO_DATE function, then reformat the date as another string using TO_CHAR, i.e.:

SELECT TO_CHAR(
         TO_DATE('15/August/2009,4:30 PM'
                ,'DD/Month/YYYY,HH:MI AM')
       ,'DD-MM-YYYY')
FROM DUAL;

15-08-2009

For example, if your table name is MYTABLE and the varchar2 column is MYDATESTRING:

SELECT TO_CHAR(
         TO_DATE(MYDATESTRING
                ,'DD/Month/YYYY,HH:MI AM')
       ,'DD-MM-YYYY')
FROM MYTABLE;

rm: cannot remove: Permission denied

The code says everything:

max@serv$ chmod 777 .

Okay, it doesn't say everything.

In UNIX and Linux, the ability to remove a file is not determined by the access bits of that file. It is determined by the access bits of the directory which contains the file.

Think of it this way -- deleting a file doesn't modify that file. You aren't writing to the file, so why should "w" on the file matter? Deleting a file requires editing the directory that points to the file, so you need "w" on the that directory.

Convert seconds to HH-MM-SS with JavaScript?

As Cleiton pointed out in his answer, moment.js can be used for this:

moment().startOf('day')
        .seconds(15457)
        .format('H:mm:ss');

Get class list for element with jQuery

I had a similar issue, for an element of type image. I needed to check whether the element was of a certain class. First I tried with:

$('<img>').hasClass("nameOfMyClass"); 

but I got a nice "this function is not available for this element".

Then I inspected my element on the DOM explorer and I saw a very nice attribute that I could use: className. It contained the names of all the classes of my element separated by blank spaces.

$('img').className // it contains "class1 class2 class3"

Once you get this, just split the string as usual.

In my case this worked:

var listOfClassesOfMyElement= $('img').className.split(" ");

I am assuming this would work with other kinds of elements (besides img).

Hope it helps.

Convert an integer to an array of digits

The immediate problem is due to you using <= temp.length() instead of < temp.length(). However, you can achieve this a lot more simply. Even if you use the string approach, you can use:

String temp = Integer.toString(guess);
int[] newGuess = new int[temp.length()];
for (int i = 0; i < temp.length(); i++)
{
    newGuess[i] = temp.charAt(i) - '0';
}

You need to make the same change to use < newGuess.length() when printing out the content too - otherwise for an array of length 4 (which has valid indexes 0, 1, 2, 3) you'll try to use newGuess[4]. The vast majority of for loops I write use < in the condition, rather than <=.

How to extract text from a PDF file?

Here is the simplest code for extracting text

code:

# importing required modules
import PyPDF2

# creating a pdf file object
pdfFileObj = open('filename.pdf', 'rb')

# creating a pdf reader object
pdfReader = PyPDF2.PdfFileReader(pdfFileObj)

# printing number of pages in pdf file
print(pdfReader.numPages)

# creating a page object
pageObj = pdfReader.getPage(5)

# extracting text from page
print(pageObj.extractText())

# closing the pdf file object
pdfFileObj.close()

Multiple lines of text in UILabel

You can do that via the Storyboard too:

  1. Select the Label on the view controller
  2. In the Attribute Inspector, increase the value of the Line option (Press Alt+Cmd+4 to show Attributes Inspector)
  3. Double click the Label in the view controller and write or paste your text
  4. Resize the Label and/or increase the font size so that the whole text could be shown

Check if item is in an array / list

I'm also going to assume that you mean "list" when you say "array." Sven Marnach's solution is good. If you are going to be doing repeated checks on the list, then it might be worth converting it to a set or frozenset, which can be faster for each check. Assuming your list of strs is called subjects:

subject_set = frozenset(subjects)
if query in subject_set:
    # whatever

Django: Get list of model fields?

As most of answers are outdated I'll try to update you on Django 2.2 Here posts- your app (posts, blog, shop, etc.)

1) From model link: https://docs.djangoproject.com/en/stable/ref/models/meta/

from posts.model import BlogPost

all_fields = BlogPost._meta.fields
#or
all_fields = BlogPost._meta.get_fields()

Note that:

all_fields=BlogPost._meta.get_fields()

Will also get some relationships, which, for ex: you can not display in a view.
As in my case:

Organisation._meta.fields
(<django.db.models.fields.AutoField: id>, <django.db.models.fields.DateField: created>...

and

Organisation._meta.get_fields()
(<ManyToOneRel: crm.activity>, <django.db.models.fields.AutoField: id>, <django.db.models.fields.DateField: created>...

2) From instance

from posts.model import BlogPost

bp = BlogPost()
all_fields = bp._meta.fields

3) From parent model

Let's suppose that we have Post as the parent model and you want to see all the fields in a list, and have the parent fields to be read-only in Edit mode.

from django.contrib import admin
from posts.model import BlogPost 

@admin.register(BlogPost)
class BlogPost(admin.ModelAdmin):
    all_fields = [f.name for f in Organisation._meta.fields]
    parent_fields = BlogPost.get_deferred_fields(BlogPost)

    list_display = all_fields
    read_only = parent_fields

What would be the Unicode character for big bullet in the middle of the character?

http://www.unicode.org is the place to look for symbol names.

? BLACK CIRCLE        25CF
? MEDIUM BLACK CIRCLE 26AB
? BLACK LARGE CIRCLE  2B24

or even:

 NEW MOON SYMBOL   1F311

Good luck finding a font that supports them all. Only one shows up in Windows 7 with Chrome.

Convert and format a Date in JSP

<%@ page language="java" contentType="text/html; charset=UTF-8"
 pageEncoding="UTF-8"%>
 <!DOCTYPE html>
 <html dir="ltr" lang="en-US">
 <head>
 <meta charset="UTF-8" />
  <title>JSP with the current date</title>
  </head>
 <body>
 <%java.text.DateFormat df = new java.text.SimpleDateFormat("dd/MM/yyyy"); %>
<h1>Current Date: <%= df.format(new java.util.Date()) %> </h1>
</body>
</html>

Output: Current Date: 10/03/2010

How to display special characters in PHP

$str = "Is your name O\'vins?";

// Outputs: Is your name O'vins? echo stripslashes($str);

#pragma pack effect

I've used it in code before, though only to interface with legacy code. This was a Mac OS X Cocoa application that needed to load preference files from an earlier, Carbon version (which was itself backwards-compatible with the original M68k System 6.5 version...you get the idea). The preference files in the original version were a binary dump of a configuration structure, that used the #pragma pack(1) to avoid taking up extra space and saving junk (i.e. the padding bytes that would otherwise be in the structure).

The original authors of the code had also used #pragma pack(1) to store structures that were used as messages in inter-process communication. I think the reason here was to avoid the possibility of unknown or changed padding sizes, as the code sometimes looked at a specific portion of the message struct by counting a number of bytes in from the start (ewww).

How do I revert to a previous package in Anaconda?

I know it was not available at the time, but now you could also use Anaconda navigator to install a specific version of packages in the environments tab.

1030 Got error 28 from storage engine

A simple: $sth->finish(); Would probably save you from worrying about this. Mysql uses the system's tmp space instead of it's own space.

How to convert List<Integer> to int[] in Java?

With Eclipse Collections, you can do the following if you have a list of type java.util.List<Integer>:

List<Integer> integers = Lists.mutable.with(1, 2, 3, 4, 5);
int[] ints = LazyIterate.adapt(integers).collectInt(i -> i).toArray();

Assert.assertArrayEquals(new int[]{1, 2, 3, 4, 5}, ints);

If you already have an Eclipse Collections type like MutableList, you can do the following:

MutableList<Integer> integers = Lists.mutable.with(1, 2, 3, 4, 5);
int[] ints = integers.asLazy().collectInt(i -> i).toArray();

Assert.assertArrayEquals(new int[]{1, 2, 3, 4, 5}, ints);

Note: I am a committer for Eclipse Collections

How to run a command as a specific user in an init script?

On RHEL systems, the /etc/rc.d/init.d/functions script is intended to provide similar to what you want. If you source that at the top of your init script, all of it's functions become available.

The specific function provided to help with this is daemon. If you are intending to use it to start a daemon-like program, a simple usage would be:

daemon --user=username command

If that is too heavy-handed for what you need, there is runuser (see man runuser for full info; some versions may need -u prior to the username):

/sbin/runuser username -s /bin/bash -c "command(s) to run as user username"

How do I set the proxy to be used by the JVM

Add this before you connect to a URL behind a proxy.

System.getProperties().put("http.proxyHost", "someProxyURL");
System.getProperties().put("http.proxyPort", "someProxyPort");
System.getProperties().put("http.proxyUser", "someUserName");
System.getProperties().put("http.proxyPassword", "somePassword");

java.sql.SQLException: Incorrect string value: '\xF0\x9F\x91\xBD\xF0\x9F...'

Weirdly, I found that REMOVING &characterEncoding=UTF-8 from the JDBC url did the trick for me with similar issues.

Based on my properties,

jdbc_url=jdbc:mysql://localhost:3306/dbName?useUnicode=true

I think this supports what @Esailija has said above, i.e. my MySQL, which is indeed 5.5, is figuring out its own favorite flavor of UTF-8 encoding.

(Note, I'm also specifying the InputStream I'm reading from as UTF-8 in the java code, which probably doesn't hurt)...

Safe String to BigDecimal conversion

String value = "1,000,000,000.999999999999999";
BigDecimal money = new BigDecimal(value.replaceAll(",", ""));
System.out.println(money);

Full code to prove that no NumberFormatException is thrown:

import java.math.BigDecimal;

public class Tester {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String value = "1,000,000,000.999999999999999";
        BigDecimal money = new BigDecimal(value.replaceAll(",", ""));
        System.out.println(money);
    }
}

Output

1000000000.999999999999999

When to use: Java 8+ interface default method, vs. abstract method

Regarding your query of

So when should interface with default methods be used and when should an abstract class be used? Are the abstract classes still useful in that scenario?

java documentation provides perfect answer.

Abstract Classes Compared to Interfaces:

Abstract classes are similar to interfaces. You cannot instantiate them, and they may contain a mix of methods declared with or without an implementation.

However, with abstract classes, you can declare fields that are not static and final, and define public, protected, and private concrete methods.

With interfaces, all fields are automatically public, static, and final, and all methods that you declare or define (as default methods) are public. In addition, you can extend only one class, whether or not it is abstract, whereas you can implement any number of interfaces.

Use cases for each of them have been explained in below SE post:

What is the difference between an interface and abstract class?

Are the abstract classes still useful in that scenario?

Yes. They are still useful. They can contain non-static, non-final methods and attributes (protected, private in addition to public), which is not possible even with Java-8 interfaces.

How to run JUnit tests with Gradle?

If you set up your project with the default gradle package structure, i.e.:

src/main/java
src/main/resources
src/test/java
src/test/resources

then you won't need to modify sourceSets to run your tests. Gradle will figure out that your test classes and resources are in src/test. You can then run as Oliver says above. One thing to note: Be careful when setting property files and running your test classes with both gradle and you IDE. I use Eclipse, and when running JUnit from it, Eclipse chooses one classpath (the bin directory) whereas gradle chooses another (the build directory). This can lead to confusion if you edit a resource file, and don't see your change reflected at test runtime.

What's the common practice for enums in Python?

class Materials:
    Shaded, Shiny, Transparent, Matte = range(4)

>>> print Materials.Matte
3

Changing the URL in react-router v4 without using Redirect or Link

Try this,

this.props.router.push('/foo')

warning works for versions prior to v4

and

this.props.history.push('/foo')

for v4 and above

Edit existing excel workbooks and sheets with xlrd and xlwt

As I wrote in the edits of the op, to edit existing excel documents you must use the xlutils module (Thanks Oliver)

Here is the proper way to do it:

#xlrd, xlutils and xlwt modules need to be installed.  
#Can be done via pip install <module>
from xlrd import open_workbook
from xlutils.copy import copy

rb = open_workbook("names.xls")
wb = copy(rb)

s = wb.get_sheet(0)
s.write(0,0,'A1')
wb.save('names.xls')

This replaces the contents of the cell located at a1 in the first sheet of "names.xls" with the text "a1", and then saves the document.

Remove an onclick listener

    /**
 * Remove an onclick listener
 *
 * @param view
 * @author [email protected]
 * @website https://github.com/androidmalin
 * @data 2016-05-16
 */
public static void unBingListener(View view) {
    if (view != null) {
        try {
            if (view.hasOnClickListeners()) {
                view.setOnClickListener(null);

            }

            if (view.getOnFocusChangeListener() != null) {
                view.setOnFocusChangeListener(null);

            }

            if (view instanceof ViewGroup && !(view instanceof AdapterView)) {
                ViewGroup viewGroup = (ViewGroup) view;
                int viewGroupChildCount = viewGroup.getChildCount();
                for (int i = 0; i < viewGroupChildCount; i++) {
                    unBingListener(viewGroup.getChildAt(i));
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

Is there an upside down caret character?

?????????????????????

??? H???,s ? ??????u? s??? ???
^^^ Here's a matching set. ^^^

^^^^^^^^^^^^^^^^^^^^^

"Actual size": ?^?^
(more info)


Edit: Another Option...

?????????? Unicode #8897 / U+22C1 (info) named N-ARY LOGICAL OR

?????????? Unicode #8896 / U+22C0 (info) named N-ARY LOGICAL AND

"Actual size": ????

Return in Scala

This topic is actually a little more complicated as described in the answers so far. This blogpost by Rob Norris explains it in more detail and gives examples on when using return will actually break your code (or at least have non-obvious effects).

At this point let me just quote the essence of the post. The most important statement is right in the beginning. Print this as a poster and put it to your wall :-)

The return keyword is not “optional” or “inferred”; it changes the meaning of your program, and you should never use it.

It gives one example, where it actually breaks something, when you inline a function

// Inline add and addR
def sum(ns: Int*): Int = ns.foldLeft(0)((n, m) => n + m) // inlined add

scala> sum(33, 42, 99)
res2: Int = 174 // alright

def sumR(ns: Int*): Int = ns.foldLeft(0)((n, m) => return n + m) // inlined addR

scala> sumR(33, 42, 99)
res3: Int = 33 // um.

because

A return expression, when evaluated, abandons the current computation and returns to the caller of the method in which return appears.

This is only one of the examples given in the linked post and it's the easiest to understand. There're more and I highly encourage you, to go there, read and understand.

When you come from imperative languages like Java, this might seem odd at first, but once you get used to this style it will make sense. Let me close with another quote:

If you find yourself in a situation where you think you want to return early, you need to re-think the way you have defined your computation.

Setting Java heap space under Maven 2 on Windows

It worked - To change in Eclipse, go to Window -> Preferences -> Java -> Installed JREs. Select the checked JRE/JDK and click edit.

Default VM Arguments = -Xms128m -Xmx1024m

How do you move a file?

Using TortoiseSVN I just right-click and drag the folder from one location to another. When you release the right-click you'll have the option to "SVN Move Version File." However, I believe that SVN doesn't do anything "fancy" there, but simply deletes the file in the previous location and Adds it to the new location.

Assembly - JG/JNLE/JL/JNGE after CMP

Addition and subtraction in two's complement is the same for signed and unsigned numbers

The key observation is that CMP is basically subtraction, and:

In two's complement (integer representation used by x86), signed and unsigned addition are exactly the same operation

This allows for example hardware developers to implement it more efficiently with just one circuit.

So when you give input bytes to the x86 ADD instruction for example, it does not care if they are signed or not.

However, ADD does set a few flags depending on what happened during the operation:

  • carry: unsigned addition or subtraction result does not fit in bit size, e.g.: 0xFF + 0x01 or 0x00 - 0x01

    For addition, we would need to carry 1 to the next level.

  • sign: result has top bit set. I.e.: is negative if interpreted as signed.

  • overflow: input top bits are both 0 and 0 or 1 and 1 and output inverted is the opposite.

    I.e. signed operation changed sigedness in an impossible way (e.g. positive + positive or negative

We can then interpret those flags in a way that makes comparison match our expectations for signed or unsigned numbers.

This interpretation is exactly what JA vs JG and JB vs JL do for us!

Code example

Here is GNU GAS a code snippet to make this more concrete:

/* 0x0 ==
 *
 * * 0 in 2's complement signed
 * * 0 in 2's complement unsigned
 */
mov $0, %al

/* 0xFF ==
 *
 * *  -1 in 2's complement signed
 * * 255 in 2's complement unsigned
 */
mov $0xFF, %bl

/* Do the operation "Is al < bl?" */
cmp %bl, %al

Note that AT&T syntax is "backwards": mov src, dst. So you have to mentally reverse the operands for the condition codes to make sense with cmp. In Intel syntax, this would be cmp al, bl

After this point, the following jumps would be taken:

  • JB, because 0 < 255
  • JNA, because !(0 > 255)
  • JNL, because !(0 < -1)
  • JG, because 0 > -1

Note how in this particular example the signedness mattered, e.g. JB is taken but not JL.

Runnable example with assertions.

Equals / Negated versions like JLE / JNG are just aliases

By looking at the Intel 64 and IA-32 Architectures Software Developer's Manuals Volume 2 section "Jcc - Jump if Condition Is Met" we see that the encodings are identical, for example:

Opcode  Instruction  Description
7E cb   JLE rel8     Jump short if less or equal (ZF=1 or SF ? OF).
7E cb   JNG rel8     Jump short if not greater (ZF=1 or SF ? OF).

How to find out the number of CPUs using python

len(os.sched_getaffinity(0)) is what you usually want

https://docs.python.org/3/library/os.html#os.sched_getaffinity

os.sched_getaffinity(0) (added in Python 3) returns the set of CPUs available considering the sched_setaffinity Linux system call, which limits which CPUs a process and its children can run on.

0 means to get the value for the current process. The function returns a set() of allowed CPUs, thus the need for len().

multiprocessing.cpu_count() and os.cpu_count() on the other hand just returns the total number of physical CPUs.

The difference is especially important because certain cluster management systems such as Platform LSF limit job CPU usage with sched_getaffinity.

Therefore, if you use multiprocessing.cpu_count(), your script might try to use way more cores than it has available, which may lead to overload and timeouts.

We can see the difference concretely by restricting the affinity with the taskset utility, which allows us to control the affinity of a process.

Minimal taskset example

For example, if I restrict Python to just 1 core (core 0) in my 16 core system:

taskset -c 0 ./main.py

with the test script:

main.py

#!/usr/bin/env python3

import multiprocessing
import os

print(multiprocessing.cpu_count())
print(os.cpu_count())
print(len(os.sched_getaffinity(0)))

then the output is:

16
16
1

Vs nproc

nproc does respect the affinity by default and:

taskset -c 0 nproc

outputs:

1

and man nproc makes that quite explicit:

print the number of processing units available

Therefore, len(os.sched_getaffinity(0)) behaves like nproc by default.

nproc has the --all flag for the less common case that you want to get the physical CPU count without considering taskset:

taskset -c 0 nproc --all

os.cpu_count documentation

The documentation of os.cpu_count also briefly mentions this https://docs.python.org/3.8/library/os.html#os.cpu_count

This number is not equivalent to the number of CPUs the current process can use. The number of usable CPUs can be obtained with len(os.sched_getaffinity(0))

The same comment is also copied on the documentation of multiprocessing.cpu_count: https://docs.python.org/3/library/multiprocessing.html#multiprocessing.cpu_count

From the 3.8 source under Lib/multiprocessing/context.py we also see that multiprocessing.cpu_count just forwards to os.cpu_count, except that the multiprocessing one throws an exception instead of returning None if os.cpu_count fails:

    def cpu_count(self):
        '''Returns the number of CPUs in the system'''
        num = os.cpu_count()
        if num is None:
            raise NotImplementedError('cannot determine number of cpus')
        else:
            return num

3.8 availability: systems with a native sched_getaffinity function

The only downside of this os.sched_getaffinity is that this appears to be UNIX only as of Python 3.8.

cpython 3.8 seems to just try to compile a small C hello world with a sched_setaffinity function call during configuration time, and if not present HAVE_SCHED_SETAFFINITY is not set and the function will likely be missing:

psutil.Process().cpu_affinity(): third-party version with a Windows port

The third-party psutil package (pip install psutil) had been mentioned at: https://stackoverflow.com/a/14840102/895245 but not the cpu_affinity function: https://psutil.readthedocs.io/en/latest/#psutil.Process.cpu_affinity

Usage:

import psutil
print(len(psutil.Process().cpu_affinity()))

This function does the same as the standard library os.sched_getaffinity on Linux, but they have also implemented it for Windows by making a call to the GetProcessAffinityMask Windows API function:

So in other words: those Windows users have to stop being lazy and send a patch to the upstream stdlib :-)

Tested in Ubuntu 16.04, Python 3.5.2.

SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens on line 102

You didn't bind all your bindings here

$sql = "SELECT SQL_CALC_FOUND_ROWS *, UNIX_TIMESTAMP(publicationDate) AS publicationDate     FROM comments WHERE articleid = :art 
ORDER BY " . mysqli_escape_string($order) . " LIMIT :numRows";

$st = $conn->prepare( $sql );
$st->bindValue( ":art", $art, PDO::PARAM_INT );

You've declared a binding called :numRows but you never actually bind anything to it.

UPDATE 2019: I keep getting upvotes on this and that reminded me of another suggestion

Double quotes are string interpolation in PHP, so if you're going to use variables in a double quotes string, it's pointless to use the concat operator. On the flip side, single quotes are not string interpolation, so if you've only got like one variable at the end of a string it can make sense, or just use it for the whole string.

In fact, there's a micro op available here since the interpreter doesn't care about parsing the string for variables. The boost is nearly unnoticable and totally ignorable on a small scale. However, in a very large application, especially good old legacy monoliths, there can be a noticeable performance increase if strings are used like this. (and IMO, it's easier to read anyway)

Expression must be a modifiable lvalue

You test k = M instead of k == M.
Maybe it is what you want to do, in this case, write if (match == 0 && (k = M))

How can I link to a specific glibc version?

In my opinion, the laziest solution (especially if you don't rely on latest bleeding edge C/C++ features, or latest compiler features) wasn't mentioned yet, so here it is:

Just build on the system with the oldest GLIBC you still want to support.

This is actually pretty easy to do nowadays with technologies like chroot, or KVM/Virtualbox, or docker, even if you don't really want to use such an old distro directly on any pc. In detail, to make a maximum portable binary of your software I recommend following these steps:

  1. Just pick your poison of sandbox/virtualization/... whatever, and use it to get yourself a virtual older Ubuntu LTS and compile with the gcc/g++ it has in there by default. That automatically limits your GLIBC to the one available in that environment.

  2. Avoid depending on external libs outside of foundational ones: like, you should dynamically link ground-level system stuff like glibc, libGL, libxcb/X11/wayland things, libasound/libpulseaudio, possibly GTK+ if you use that, but otherwise preferrably statically link external libs/ship them along if you can. Especially mostly self-contained libs like image loaders, multimedia decoders, etc can cause less breakage on other distros (breakage can be caused e.g. if only present somewhere in a different major version) if you statically ship them.

With that approach you get an old-GLIBC-compatible binary without any manual symbol tweaks, without doing a fully static binary (that may break for more complex programs because glibc hates that, and which may cause licensing issues for you), and without setting up any custom toolchain, any custom glibc copy, or whatever.

How to auto-reload files in Node.js?

my app structure:

NodeAPP (folder)
   |-- app (folder)
      |-- all other file is here
   |-- node_modules (folder)
   |-- package.json
   |-- server.js (my server file)

first install reload with this command:

npm install [-g] [--save-dev] reload

then change package.json:

"scripts": {
    "start": "nodemon -e css,ejs,js,json --watch app"
}

now you must use reload in your server file:

var express = require('express');
var reload = require('reload');
var app = express();

app.set('port', process.env.PORT || 3000);

var server = app.listen(app.get('port'), function() {
    console.log( 'server is running on port ' + app.get('port'));
});

reload(server, app);

and for last change, end of your response send this script:

<script src="/reload/reload.js"></script>

now start your app with this code:

npm start

frequent issues arising in android view, Error parsing XML: unbound prefix

This error usually occurs if you have not included the xmlns:mm properly, it occurs usually in the first line of code.

for me it was..

xmlns:mm="http://millennialmedia.com/android/schema"

that i missed in first line of the code

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:mm="http://millennialmedia.com/android/schema"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_marginTop="50dp"
android:layout_marginBottom="50dp"
android:background="@android:color/transparent" >

JOptionPane - input dialog box program

One solution is to actually use an integer array instead of separate test strings:

You could loop parse the response from JOptionPane.showInputDialog into the individual elements of the array.

Arrays.sort could be used to sort them to allow you to pick out the 2 highest values.

The average can be easily calculated then by adding these 2 values & dividing by 2.

int[] testScore = new int[3];

for (int i = 0; i < testScore.length; i++) {
   testScore[i] = Integer.parseInt(JOptionPane.showInputDialog("Please input mark for test " + i + ": "));
}

Arrays.sort(testScore);
System.out.println("Average: " + (testScore[1] + testScore[2])/2.0);

What is the best/simplest way to read in an XML file in Java application?

JAXB is simple to use and is included in Java 6 SE. With JAXB, or other XML data binding such as Simple, you don't have to handle the XML yourself, most of the work is done by the library. The basic usage is to add annotation to your existing POJO. These annotation are then used to generate an XML Schema for you data and also when reading/writing your data from/to a file.

Can you issue pull requests from the command line on GitHub?

I personally like to view the diff in GitHub prior to opening the PR. Additionally, I prefer writing the PR description on GitHub.

For those reasons, I made an alias (or technically a function without arguments), that opens the diff in GitHub between your current branch and master. If you add this to your .zshrc or .bashrc, you will be able to simply type open-pr and see your changes in GitHub. FYI, you will need to have your changes pushed.

function open-pr() {
  # Get the root of the github project, based on where you are configured to push to.  Ex: https://github.com/tensorflow/tensorflow
  base_uri=$(git remote -v | grep push | tr '\t' ' ' | cut -d ' ' -f 2 | rev | cut -d '.' -f 2- | rev)

  # Get your current branch name
  branch=$(git branch --show-current)

  # Create PR url and open in the default web browser
  url="${base_uri}/compare/${branch}/?expand=1"
  open $url
}

Copy all the lines to clipboard

I know ten years on this should be settled but the first two answers did not work for me so I kept digging. On a Redhat (remote server) - Windows 10 (local machine), if you cannot select the whole thing with a mouse, you are stuck because the usual copies do not work between the remote and the local machine clipboards.

So, to copy on the remote Linux and to paste on the local Windows, specify the primary buffer with the * and do a nice double yank

Use gg" * yy.

Keystore change passwords

[How can I] Change the password, so I can share it with others and let them sign

Using keytool:

keytool -storepasswd -keystore /path/to/keystore
Enter keystore password:  changeit
New keystore password:  new-password
Re-enter new keystore password:  new-password

Deleting all pending tasks in celery / rabbitmq

1. To properly purge the queue of waiting tasks you have to stop all the workers (http://celery.readthedocs.io/en/latest/faq.html#i-ve-purged-messages-but-there-are-still-messages-left-in-the-queue):

$ sudo rabbitmqctl stop

or (in case RabbitMQ/message broker is managed by Supervisor):

$ sudo supervisorctl stop all

2. ...and then purge the tasks from a specific queue:

$ cd <source_dir>
$ celery amqp queue.purge <queue name>

3. Start RabbitMQ:

$ sudo rabbitmqctl start

or (in case RabbitMQ is managed by Supervisor):

$ sudo supervisorctl start all

How to force reloading php.ini file?

TL;DR; If you're still having trouble after restarting apache or nginx, also try restarting the php-fpm service.

The answers here don't always satisfy the requirement to force a reload of the php.ini file. On numerous occasions I've taken these steps to be rewarded with no update, only to find the solution I need after also restarting the php-fpm service. So if restarting apache or nginx doesn't trigger a php.ini update although you know the files are updated, try restarting php-fpm as well.

To restart the service:

Note: prepend sudo if not root

Using SysV Init scripts directly:

/etc/init.d/php-fpm restart        # typical
/etc/init.d/php5-fpm restart       # debian-style
/etc/init.d/php7.0-fpm restart     # debian-style PHP 7

Using service wrapper script

service php-fpm restart        # typical
service php5-fpm restart       # debian-style
service php7.0-fpm restart.    # debian-style PHP 7

Using Upstart (e.g. ubuntu):

restart php7.0-fpm         # typical (ubuntu is debian-based) PHP 7
restart php5-fpm           # typical (ubuntu is debian-based)
restart php-fpm            # uncommon

Using systemd (newer servers):

systemctl restart php-fpm.service        # typical
systemctl restart php5-fpm.service       # uncommon
systemctl restart php7.0-fpm.service     # uncommon PHP 7

Or whatever the equivalent is on your system.

The above commands taken directly from this server fault answer

How does Python manage int and long?

Python 2 will automatically set the type based on the size of the value. A guide of max values can be found below.

The Max value of the default Int in Python 2 is 65535, anything above that will be a long

For example:

>> print type(65535)
<type 'int'>
>>> print type(65536*65536)
<type 'long'>

In Python 3 the long datatype has been removed and all integer values are handled by the Int class. The default size of Int will depend on your CPU architecture.

For example:

  • 32 bit systems the default datatype for integers will be 'Int32'
  • 64 bit systems the default datatype for integers will be 'Int64'

The min/max values of each type can be found below:

  • Int8: [-128,127]
  • Int16: [-32768,32767]
  • Int32: [-2147483648,2147483647]
  • Int64: [-9223372036854775808,9223372036854775807]
  • Int128: [-170141183460469231731687303715884105728,170141183460469231731687303715884105727]
  • UInt8: [0,255]
  • UInt16: [0,65535]
  • UInt32: [0,4294967295]
  • UInt64: [0,18446744073709551615]
  • UInt128: [0,340282366920938463463374607431768211455]

If the size of your Int exceeds the limits mentioned above, python will automatically change it's type and allocate more memory to handle this increase in min/max values. Where in Python 2, it would convert into 'long', it now just converts into the next size of Int.

Example: If you are using a 32 bit operating system, your max value of an Int will be 2147483647 by default. If a value of 2147483648 or more is assigned, the type will be changed to Int64.

There are different ways to check the size of the int and it's memory allocation. Note: In Python 3, using the built-in type() method will always return <class 'int'> no matter what size Int you are using.

AndroidStudio: Failed to sync Install build tools

I had the same problem, in my cases this happened because I changed the time on my computer to load .apk on google play. I spent a few hours to fix "this" problem until I remembered and changed the time back.

How do I retrieve my MySQL username and password?

An improvement to the most useful answer here:

1] No need to restart the mysql server
2] Security concern for a MySQL server connected to a network

There is no need to restart the MySQL server.

use FLUSH PRIVILEGES; after the update mysql.user statement for password change.

The FLUSH statement tells the server to reload the grant tables into memory so that it notices the password change.

The --skip-grant-options enables anyone to connect without a password and with all privileges. Because this is insecure, you might want to

use --skip-grant-tables in conjunction with --skip-networking to prevent remote clients from connecting.

from: reference: resetting-permissions-generic

Simple JavaScript Checkbox Validation

var testCheckbox = document.getElementById("checkbox");  
if (!testCheckbox.checked) {
  alert("Error Message!!");
}
else {
  alert("Success Message!!");
}

How to create empty folder in java?

Looks file you use the .mkdirs() method on a File object: http://www.roseindia.net/java/beginners/java-create-directory.shtml

// Create a directory; all non-existent ancestor directories are
// automatically created
success = (new File("../potentially/long/pathname/without/all/dirs")).mkdirs();
if (!success) {
    // Directory creation failed
}

Blocking device rotation on mobile web pages

seems weird that no one proposed the CSS media query solution:

@media screen and (orientation: portrait) {
  ...
}

and the option to use a specific style sheet:

<link rel="stylesheet" type="text/css" href="css/style_p.css" media="screen and (orientation: portrait)">

MDN: https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Media_queries#orientation

Excel formula to search if all cells in a range read "True", if not, then show "False"

As it appears you have the values as text, and not the numeric True/False, then you can use either COUNTIF or SUMPRODUCT

=IF(SUMPRODUCT(--(A2:D2="False")),"False","True")
=IF(COUNTIF(A3:D3,"False*"),"False","True")

Can I extend a class using more than 1 class in PHP?

You are able to do that using Traits in PHP which announced as of PHP 5.4

Here is a quick tutorial for you, http://culttt.com/2014/06/25/php-traits/

Underline text in UIlabel

Use an attribute string:

NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString:@"Your String"]
[attrString addAttribute:(NSString*)kCTUnderlineStyleAttributeName 
                   value:[NSNumber numberWithInt:kCTUnderlineStyleSingle] 
                   range:(NSRange){0,[attrString length]}];

And then override the label - (void)drawTextInRect:(CGRect)aRect and render the text in something like:

CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSaveGState(ctx);
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attrString);
drawingRect = self.bounds;
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, drawingRect);
textFrame = CTFramesetterCreateFrame(framesetter,CFRangeMake(0,0), path, NULL);
CGPathRelease(path);
CFRelease(framesetter);
CTFrameDraw(textFrame, ctx);
CGContextRestoreGState(ctx);

Or better yet instead of overriding just use the OHAttributedLabel created by Olivier Halligon

How can I get a first element from a sorted list?

That depends on what type your list is, for ArrayList use:

list.get(0);

for LinkedList use:

list.getFirst();

if you like the array approach:

list.toArray()[0];

Base64 PNG data to HTML5 canvas

Jerryf's answer is fine, except for one flaw.

The onload event should be set before the src. Sometimes the src can be loaded instantly and never fire the onload event.

(Like Totty.js pointed out.)

var canvas = document.getElementById("c");
var ctx = canvas.getContext("2d");

var image = new Image();
image.onload = function() {
    ctx.drawImage(image, 0, 0);
};
image.src = "data:image/  png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAIAAAACDbGyAAAAAXNSR0IArs4c6QAAAAlwSFlzAAALEwAACxMBAJqcGAAAAAd0SU1FB9oMCRUiMrIBQVkAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAADElEQVQI12NgoC4AAABQAAEiE+h1AAAAAElFTkSuQmCC";

ERROR Android emulator gets killed

goto tools>android>sdkmanager and update emulator and install related API level.It worked for me

Loop structure inside gnuplot?

I have the script all.p

set ...
...
list=system('ls -1B *.dat')
plot for [file in list] file w l u 1:2 t file

Here the two last rows are literal, not heuristic. Then i run

$ gnuplot -p all.p

Change *.dat to the file type you have, or add file types.

Next step: Add to ~/.bashrc this line

alias p='gnuplot -p ~/./all.p'

and put your file all.p int your home directory and voila. You can plot all files in any directory by typing p and enter.

EDIT I changed the command, because it didn't work. Previously it contained list(i)=word(system(ls -1B *.dat),i).

How to do a background for a label will be without color?

You are right. but here is the simplest way for making the back color of the label transparent In the properties window of that label select Web.. In Web select Transparent :)

Operator overloading ==, !=, Equals

public class BOX
{
    double height, length, breadth;

    public static bool operator == (BOX b1, BOX b2)
    {
        if (b1 is null)
            return b2 is null;

        return b1.Equals(b2);
    }

    public static bool operator != (BOX b1, BOX b2)
    {
        return !(b1 == b2);
    }

    public override bool Equals(object obj)
    {
        if (obj == null)
            return false;

        return obj is BOX b2? (length == b2.length && 
                               breadth == b2.breadth && 
                               height == b2.height): false;

    }

    public override int GetHashCode()
    {
        return (height,length,breadth).GetHashCode();
    }
}

How can I deploy an iPhone application from Xcode to a real iPhone device?

Solution posted by Cawas works perfectly with XCode4, too. However, there are some changes to IDE's UI, so you need to make some research to find Run Script :)

In the Project Navigator view click the root item of the project, then in the middle window select Target, then click Build Phases tab and at the bottom you'll see Add Build Phase button, click and select Add Run Script, then paste "codesign" script posted by Cawas.

What is the best practice for creating a favicon on a web site?

I used https://iconifier.net I uploaded my image, downloaded images zip file, added images to my server, followed the directions on the site including adding the links to my index.html and it worked. My favicon now shows on my iPhone in Safari when 'Add to home screen'

Use sudo with password as parameter

The -S switch makes sudo read the password from STDIN. This means you can do

echo mypassword | sudo -S command

to pass the password to sudo

However, the suggestions by others that do not involve passing the password as part of a command such as checking if the user is root are probably much better ideas for security reasons

How can I return the current action in an ASP.NET MVC view?

Extending Dale Ragan's answer, his example for reuse, create an ApplicationController class which derives from Controller, and in turn have all your other controllers derive from that ApplicationController class rather than Controller.

Example:

public class MyCustomApplicationController : Controller {}

public class HomeController : MyCustomApplicationController {}

On your new ApplicationController create a property named ExecutingAction with this signature:

protected ActionDescriptor ExecutingAction { get; set; }

And then in the OnActionExecuting method (from Dale Ragan's answer), simply assign the ActionDescriptor to this property and you can access it whenever you need it in any of your controllers.

string currentActionName = this.ExecutingAction.ActionName;

C++ passing an array pointer as a function argument

You're over-complicating it - it just needs to be:

void generateArray(int *a, int si)
{
    for (int j = 0; j < si; j++)
        a[j] = rand() % 9;
}

int main()
{
    const int size=5;
    int a[size];

    generateArray(a, size);

    return 0;
}

When you pass an array as a parameter to a function it decays to a pointer to the first element of the array. So there is normally never a need to pass a pointer to an array.

How to discard local commits in Git?

What I do is I try to reset hard to HEAD. This will wipe out all the local commits:

git reset --hard HEAD^

CSS3's border-radius property and border-collapse:collapse don't mix. How can I use border-radius to create a collapsed table with rounded corners?

I just wrote a crazy set of CSS for this that seems to work perfectly:

table {
  border-collapse: separate;
  border-spacing: 0;
  width: 100%;
}
table td,
table th {
  border-right: 1px solid #CCC;
  border-top: 1px solid #CCC;
  padding: 3px 5px;
  vertical-align: top;
}
table td:first-child,
table th:first-child {
  border-left: 1px solid #CCC;
}
table tr:last-child td,
table tr:last-child th {
  border-bottom: 1px solid #CCC;
}
table thead + tbody tr:first-child td {
  border-top: 0;
}
table thead td,
table th {
  background: #EDEDED;
}

/* complicated rounded table corners! */
table thead:first-child tr:last-child td:first-child {
  border-bottom-left-radius: 0;
}
table thead:first-child tr:last-child td:last-child {
  border-bottom-right-radius: 0;
}
table thead + tbody tr:first-child td:first-child {
  border-top-left-radius: 0;
}
table thead + tbody tr:first-child td:last-child {
  border-top-right-radius: 0;
}
table tr:first-child td:first-child,
table thead tr:first-child td:first-child {
  border-top-left-radius: 5px;
}
table tr:first-child td:last-child,
table thead tr:first-child td:last-child {
  border-top-right-radius: 5px;
}
table tr:last-child td:first-child,
table thead:last-child tr:last-child td:first-child {
  border-bottom-left-radius: 5px;
}
table tr:last-child td:last-child,
table thead:last-child tr:last-child td:last-child {
  border-bottom-right-radius: 5px;
}

/* end complicated rounded table corners !*/

Updating and committing only a file's permissions using git version control

@fooMonster article worked for me

# git ls-tree HEAD
100644 blob 55c0287d4ef21f15b97eb1f107451b88b479bffe    script.sh

As you can see the file has 644 permission (ignoring the 100). We would like to change it to 755:

# git update-index --chmod=+x script.sh

commit the changes

# git commit -m "Changing file permissions"
[master 77b171e] Changing file permissions
0 files changed, 0 insertions(+), 0 deletions(-)
mode change 100644 => 100755 script.sh

SQL update trigger only when column is modified

You have two way for your question :

1- Use Update Command in your Trigger.

ALTER TRIGGER [dbo].[tr_SCHEDULE_Modified]
   ON [dbo].[SCHEDULE]
   AFTER UPDATE
AS BEGIN
    SET NOCOUNT ON;
    IF UPDATE (QtyToRepair) 
    BEGIN
        UPDATE SCHEDULE 
        SET modified = GETDATE()
           , ModifiedUser = SUSER_NAME()
           , ModifiedHost = HOST_NAME()
        FROM SCHEDULE S INNER JOIN Inserted I 
        ON S.OrderNo = I.OrderNo and S.PartNumber = I.PartNumber
        WHERE S.QtyToRepair <> I.QtyToRepair
    END 
END

2- Use Join between Inserted table and deleted table

ALTER TRIGGER [dbo].[tr_SCHEDULE_Modified]
   ON [dbo].[SCHEDULE]
   AFTER UPDATE
AS BEGIN
    SET NOCOUNT ON;    

    UPDATE SCHEDULE 
    SET modified = GETDATE()
       , ModifiedUser = SUSER_NAME()
       , ModifiedHost = HOST_NAME()
    FROM SCHEDULE S 
    INNER JOIN Inserted I ON S.OrderNo = I.OrderNo and S.PartNumber = I.PartNumber
    INNER JOIN Deleted D ON S.OrderNo = D.OrderNo and S.PartNumber = D.PartNumber                  
    WHERE S.QtyToRepair <> I.QtyToRepair
    AND D.QtyToRepair <> I.QtyToRepair
END

When you use update command for table SCHEDULE and Set QtyToRepair Column to new value, if new value equal to old value in one or multi row, solution 1 update all updated row in Schedule table but solution 2 update only schedule rows that old value not equal to new value.

Replace last occurrence of character in string

You don't need jQuery, just a regular expression.

This will remove the last underscore:

_x000D_
_x000D_
var str = 'a_b_c';_x000D_
console.log(  str.replace(/_([^_]*)$/, '$1')  ) //a_bc
_x000D_
_x000D_
_x000D_

This will replace it with the contents of the variable replacement:

_x000D_
_x000D_
var str = 'a_b_c',_x000D_
    replacement = '!';_x000D_
_x000D_
console.log(  str.replace(/_([^_]*)$/, replacement + '$1')  ) //a_b!c
_x000D_
_x000D_
_x000D_

What does `return` keyword mean inside `forEach` function?

The return exits the current function, but the iterations keeps on, so you get the "next" item that skips the if and alerts the 4...

If you need to stop the looping, you should just use a plain for loop like so:

$('button').click(function () {
   var arr = [1, 2, 3, 4, 5];
   for(var i = 0; i < arr.length; i++) {
     var n = arr[i]; 
     if (n == 3) {
         break;
      }
      alert(n);
   })
})

You can read more about js break & continue here: http://www.w3schools.com/js/js_break.asp

Why I can't access remote Jupyter Notebook server?

Alternatively you can just create a tunnel to the server:

ssh -i <your_key> <user@server-instance> -L 8888:127.0.0.1:8888

Then just open 127.0.0.1:8888 in your browser.

You also omit the -i <your_key> if you don't have an identity_file.

Parameter "stratify" from method "train_test_split" (scikit Learn)

In this context, stratification means that the train_test_split method returns training and test subsets that have the same proportions of class labels as the input dataset.

How to change the height of a <br>?

Another way is to use an HR. But, and here's the cunning part, make it invisible.

Thus:

<hr style="height:30pt; visibility:hidden;" />

To make a cleaner BR break simulated using the HR: Btw works in all browsers!!

{ height:2px; visibility:hidden; margin-bottom:-1px; }

Printing variables in Python 3.4

one can print values using the format method in python. This small example will help take input of two numbers a and b. Print a+b in first line and a-b in second line

print('{:d}\n{:d}'.format(a+b,a-b))

Similarly in the answer we can do

print ("{0}. {1} appears {2} times.".format(22, 'c', 9999))

The python method format() for string is used to specify a string format. So {0},{1},{2} are like array indexes called as positional parameters. Therefore {0} is assigned first value written in format (a+b), {1} is assigned the second value (a-b) and so on. We can also use keyword instead of positional parameter like for example

print("Hi! my name is {name}".format(name="rashi"))

Therefore name here is the keyword and its value is Rashi Hope it helps :)

Adding a rule in iptables in debian to open a new port

(I presume that you've concluded that it's an iptables problem by dropping the firewall completely (iptables -P INPUT ACCEPT; iptables -P OUTPUT ACCEPT; iptables -F) and confirmed that you can connect to the MySQL server from your Windows box?)

Some previous rule in the INPUT table is probably rejecting or dropping the packet. You can get around that by inserting the new rule at the top, although you might want to review your existing rules to see whether that's sensible:

iptables -I INPUT 1 -p tcp --dport 3306 -j ACCEPT

Note that iptables-save won't save the new rule persistently (i.e. across reboots) - you'll need to figure out something else for that. My usual route is to store the iptables-save output in a file (/etc/network/iptables.rules or similar) and then load then with a pre-up statement in /etc/network/interfaces).

Sample random rows in dataframe

Just for completeness sake:

dplyr also offers to draw a proportion or fraction of the sample by

df %>% sample_frac(0.33)

This is very convenient e.g. in machine learning when you have to do a certain split ratio like 80%:20%

Deck of cards JAVA

This is my implementation:

public class CardsDeck {
    private ArrayList<Card> mCards;
    private ArrayList<Card> mPulledCards;
    private Random mRandom;

public enum Suit {
    SPADES,
    HEARTS,
    DIAMONDS,
    CLUBS;
}

public enum Rank {
    TWO,
    THREE,
    FOUR,
    FIVE,
    SIX,
    SEVEN,
    EIGHT,
    NINE,
    TEN,
    JACK,
    QUEEN,
    KING,
    ACE;
}

public CardsDeck() {
    mRandom = new Random();
    mPulledCards = new ArrayList<Card>();
    mCards = new ArrayList<Card>(Suit.values().length * Rank.values().length);
    reset();
}

public void reset() {
    mPulledCards.clear();
    mCards.clear();
    /* Creating all possible cards... */
    for (Suit s : Suit.values()) {
        for (Rank r : Rank.values()) {
            Card c = new Card(s, r);
            mCards.add(c);
        }
    }
}


public static class Card {

    private Suit mSuit;
    private Rank mRank;

    public Card(Suit suit, Rank rank) {
        this.mSuit = suit;
        this.mRank = rank;
    }

    public Suit getSuit() {
        return mSuit;
    }

    public Rank getRank() {
        return mRank;
    }

    public int getValue() {
        return mRank.ordinal() + 2;
    }

    @Override
    public boolean equals(Object o) {
        return (o != null && o instanceof Card && ((Card) o).mRank == mRank && ((Card) o).mSuit == mSuit);
    }


}

/**
 * get a random card, removing it from the pack
 * @return
 */
public Card pullRandom() {
    if (mCards.isEmpty())
        return null;

    Card res = mCards.remove(randInt(0, mCards.size() - 1));
    if (res != null)
        mPulledCards.add(res);
    return res;
}

/**
 * Get a random cards, leaves it inside the pack 
 * @return
 */
public Card getRandom() {
    if (mCards.isEmpty())
        return null;

    Card res = mCards.get(randInt(0, mCards.size() - 1));
    return res;
}

/**
 * Returns a pseudo-random number between min and max, inclusive.
 * The difference between min and max can be at most
 * <code>Integer.MAX_VALUE - 1</code>.
 *
 * @param min Minimum value
 * @param max Maximum value.  Must be greater than min.
 * @return Integer between min and max, inclusive.
 * @see java.util.Random#nextInt(int)
 */
public int randInt(int min, int max) {
    // nextInt is normally exclusive of the top value,
    // so add 1 to make it inclusive
    int randomNum = mRandom.nextInt((max - min) + 1) + min;
    return randomNum;
}


public boolean isEmpty(){
    return mCards.isEmpty();
}
}

How to override toString() properly in Java?

we can even write like this by creating a new String object in the class and assigning it what ever we want in constructor and return that in toString method which is overridden

public class Student{  
 int id;  
 String name;  
 String address;  
 String details;
 Student(int id, String name, String address){  
 this.id=id;  
 this.name=name;  
 this.address=address;  
 this.details=id+"  "+name+"  "+address;  
 }  

//overriding the toString() method  
public String toString(){ 
  return details;  
 }  
 public static void main(String args[]){  
   Student s1=new Student(100,"Joe","success");  
   Student s2=new Student(50,"Jeff","fail");  

   System.out.println(s1);//compiler writes here s1.toString()  
   System.out.println(s2);//compiler writes here s2.toString()  
 }  
}

Error java.lang.OutOfMemoryError: GC overhead limit exceeded

Solved:
Just add
org.gradle.jvmargs=-Xmx1024m
in
gradle.properties
and if it does not exist, create it.

How to "pull" from a local branch into another one?

If you are looking for a brand new pull from another branch like from local to master you can follow this.

git commit -m "Initial Commit"
git add .
git pull --rebase git_url
git push origin master

Twitter - How to embed native video from someone else's tweet into a New Tweet or a DM

I found a faster way of embedding:

  • Just copy the link.
  • Paste the link and remove the "?s=19" part and add "/video/1"
  • That's it.

Node.js Error: Cannot find module express

Given you have installed node on your system, install Express locally for your project using the following for Windows:

npm install express

or

npm install express --save

You might give it global access by using:

npm install -g express --save

PHP7 : install ext-dom issue

simply run

sudo apt install php-xml

its worked for me

How to stretch a fixed number of horizontal navigation items evenly and fully across a specified container

Have you tried setting the li width to, say, 16% with a margin of 0.5%?

nav li {
  line-height: 87px;
  float: left;
  text-align: center;
  width: 16%;
  margin-right: 0.5%;
}

edit: I would set the UL to 100% width:

nav ul { width: 100%; margin: 0 auto; }

Test if a string contains any of the strings from an array

And if you are looking for case insensitive match, use pattern

Pattern pattern = Pattern.compile("\\bitem1 |item2\\b",java.util.regex.Pattern.CASE_INSENSITIVE);

Matcher matcher = pattern.matcher(input);
if (matcher.find()) { 
    ...
}

Find files containing a given text

Sounds like a perfect job for grep or perhaps ack

Or this wonderful construction:

find . -type f \( -name *.php -o -name *.html -o -name *.js \) -exec grep "document.cookie\|setcookie" /dev/null {} \;

Python error "ImportError: No module named"

Fixed my issue by writing print (sys.path) and found out that python was using out of date packages despite a clean install. Deleting these made python automatically use the correct packages.

Bootstrap date and time picker

If you are still interested in a javascript api to select both date and time data, have a look at these projects which are forks of bootstrap datepicker:

The first fork is a big refactor on the parsing/formatting codebase and besides providing all views to select date/time using mouse/touch, it also has a mask option (by default) which lets the user to quickly type the date/time based on a pre-specified format.

How to unescape HTML character entities in Java?

The most reliable way is with

String cleanedString = StringEscapeUtils.unescapeHtml4(originalString);

from org.apache.commons.lang3.StringEscapeUtils.

And to escape the whitespaces

cleanedString = cleanedString.trim();

This will ensure that whitespaces due to copy and paste in web forms to not get persisted in DB.

How to convert a Datetime string to a current culture datetime string

This works for me:

string myTime = DateTime.Parse("12/1/2011")
                        .ToString(CultureInfo.GetCultureInfo("en-GB").DateTimeFormat.ShortDatePattern);

Foreign Key Django Model

I would advise, it is slightly better practise to use string model references for ForeignKey relationships if utilising an app based approach to seperation of logical concerns .

So, expanding on Martijn Pieters' answer:

class Person(models.Model):
    name = models.CharField(max_length=50)
    birthday = models.DateField()
    anniversary = models.ForeignKey(
        'app_label.Anniversary', on_delete=models.CASCADE)
    address = models.ForeignKey(
        'app_label.Address', on_delete=models.CASCADE)

class Address(models.Model):
    line1 = models.CharField(max_length=150)
    line2 = models.CharField(max_length=150)
    postalcode = models.CharField(max_length=10)
    city = models.CharField(max_length=150)
    country = models.CharField(max_length=150)

class Anniversary(models.Model):
    date = models.DateField()

fe_sendauth: no password supplied

This occurs if the password for the database is not given.

default="postgres://postgres:[email protected]:5432/DBname"

git command to move a folder inside another

I solved this on windows by doing this:

  • Open Power shell console
  • run dir
  • Alt-click and drag over the file/folder name column, then copy
  • Paste to notepad++
  • run replace with regex: replace (.*) with git mv ".\\\1" ".\\<New_Folder_Here>\"
  • copy all text from notepad++ into powershell
  • hit enter

Best way to find os name and version in Unix/Linux platform

The "lsb_release" command provides certain Linux Standard Base and distribution-specific information. So using the below command we can get Operating system name and operating system version.

"lsb_release -a"

Java time-based map/cache with expiring keys

Sounds like ehcache is overkill for what you want, however note that it does not need external configuration files.

It is generally a good idea to move configuration into a declarative configuration files ( so you don't need to recompile when a new installation requires a different expiry time ), but it is not at all required, you can still configure it programmatically. http://www.ehcache.org/documentation/user-guide/configuration

Html.DropdownListFor selected value not being set

If you know what will be in the view, you can also set the default value from Controller as well rather then set up it into the view/cshtml file. No need to set default value from HTML side.

In the Controller file.

commission.TypeofCommission = 1;
return View(commission);

In the .cshtml file.

@Html.DropDownListFor(row => row.TypeofCommission, new SelectList(Model.commissionTypeModelList, "type", "typeName"), "--Select--")

Add colorbar to existing axis

The colorbar has to have its own axes. However, you can create an axes that overlaps with the previous one. Then use the cax kwarg to tell fig.colorbar to use the new axes.

For example:

import numpy as np
import matplotlib.pyplot as plt

data = np.arange(100, 0, -1).reshape(10, 10)

fig, ax = plt.subplots()
cax = fig.add_axes([0.27, 0.8, 0.5, 0.05])

im = ax.imshow(data, cmap='gist_earth')
fig.colorbar(im, cax=cax, orientation='horizontal')
plt.show()

enter image description here

Save string to the NSUserDefaults?

-(void)saveToUserDefaults:(NSString*)string_to_store keys:(NSString *)key_for_the_String
{
    NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];

    if (standardUserDefaults) {
        [standardUserDefaults setObject:string_to_store forKey:key_for_the_String];
        [standardUserDefaults synchronize];
    }
}

And call it by:

[self saveToUserDefaults:@"string_to_store" : @"key_for_the_string"];

Retrieve the string by using:

NSString * stored_string = [[NSUserDefaults standardUserDefaults] stringforkey:key_for_the_String]

HTML form readonly SELECT tag/input

input being your <select> element:

input.querySelectorAll(':not([selected])').forEach(option => {
  option.disabled = true
})

This will keep the select in the data (as it's not disabled) and only the option that are not selected are disabled, therefore not selectable. The result is a readable select that cannot be changed (=> read only).

How to set Google Chrome in WebDriver

public void setUp() throws Exception {

 System.setProperty("webdriver.chrome.driver","Absolute path of Chrome driver");

 driver =new ChromeDriver();
 baseUrl = "URL/";

    driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);
  }

How to define two fields "unique" as couple

Django 2.2+

Using the constraints features UniqueConstraint is preferred over unique_together.

From the Django documentation for unique_together:

Use UniqueConstraint with the constraints option instead.
UniqueConstraint provides more functionality than unique_together.
unique_together may be deprecated in the future.

For example:

class Volume(models.Model):
    id = models.AutoField(primary_key=True)
    journal_id = models.ForeignKey(Journals, db_column='jid', null=True, verbose_name="Journal")
    volume_number = models.CharField('Volume Number', max_length=100)
    comments = models.TextField('Comments', max_length=4000, blank=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(fields=['journal_id', 'volume_number'], name='name of constraint')
        ]

Sort columns of a dataframe by column name

Here's the obligatory dplyr answer in case somebody wants to do this with the pipe.

test %>% 
    select(sort(names(.)))

Dialog to pick image from gallery or from camera

The code below can be used for taking a photo and for picking a photo. Just show a dialog with two options and upon selection, use the appropriate code.

To take picture from camera:

Intent takePicture = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(takePicture, 0);//zero can be replaced with any action code (called requestCode)

To pick photo from gallery:

Intent pickPhoto = new Intent(Intent.ACTION_PICK,
           android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(pickPhoto , 1);//one can be replaced with any action code

onActivityResult code:

protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) { 
    super.onActivityResult(requestCode, resultCode, imageReturnedIntent); 
    switch(requestCode) {
    case 0:
        if(resultCode == RESULT_OK){  
            Uri selectedImage = imageReturnedIntent.getData();
            imageview.setImageURI(selectedImage);
        }

    break; 
    case 1:
        if(resultCode == RESULT_OK){  
            Uri selectedImage = imageReturnedIntent.getData();
            imageview.setImageURI(selectedImage);
        }
    break;
    }
}

Finally add this permission in the manifest file:

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

Executing Batch File in C#

Using CliWrap:

var result = await Cli.Wrap("foobar.bat").ExecuteBufferedAsync();

var exitCode = result.ExitCode;
var stdOut = result.StandardOutput;

How do I handle ImeOptions' done button click?

I ended up with a combination of Roberts and chirags answers:

((EditText)findViewById(R.id.search_field)).setOnEditorActionListener(
        new EditText.OnEditorActionListener() {
    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
        // Identifier of the action. This will be either the identifier you supplied,
        // or EditorInfo.IME_NULL if being called due to the enter key being pressed.
        if (actionId == EditorInfo.IME_ACTION_SEARCH
                || actionId == EditorInfo.IME_ACTION_DONE
                || event.getAction() == KeyEvent.ACTION_DOWN
                && event.getKeyCode() == KeyEvent.KEYCODE_ENTER) {
            onSearchAction(v);
            return true;
        }
        // Return true if you have consumed the action, else false.
        return false;
    }
});

Update: The above code would some times activate the callback twice. Instead I've opted for the following code, which I got from the Google chat clients:

public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
    // If triggered by an enter key, this is the event; otherwise, this is null.
    if (event != null) {
        // if shift key is down, then we want to insert the '\n' char in the TextView;
        // otherwise, the default action is to send the message.
        if (!event.isShiftPressed()) {
            if (isPreparedForSending()) {
                confirmSendMessageIfNeeded();
            }
            return true;
        }
        return false;
    }

    if (isPreparedForSending()) {
        confirmSendMessageIfNeeded();
    }
    return true;
}

Package Manager Console Enable-Migrations CommandNotFoundException only in a specific VS project

In VS 2013, try to install the UPDATE 1(RC1) and the problem is resolved.

H2 database error: Database may be already in use: "Locked by another process"

You can also visit the "Preferences" tab from the H2 Console and shutdown all active sessions by pressing the shutdown button.

SQL server ignore case in a where expression

In the default configuration of a SQL Server database, string comparisons are case-insensitive. If your database overrides this setting (through the use of an alternate collation), then you'll need to specify what sort of collation to use in your query.

SELECT * FROM myTable WHERE myField = 'sOmeVal' COLLATE SQL_Latin1_General_CP1_CI_AS

Note that the collation I provided is just an example (though it will more than likely function just fine for you). A more thorough outline of SQL Server collations can be found here.

Is there a way to specify which pytest tests to run from a file?

Here's a possible partial answer, because it only allows selecting the test scripts, not individual tests within those scripts.

And it also limited by my using legacy compatibility mode vs unittest scripts, so not guaranteeing it would work with native pytest.

Here goes:

  1. create a new dictory, say subset_tests_directory.
  2. ln -s tests_directory/foo.py
  3. ln -s tests_directory/bar.py

  4. be careful about imports which implicitly assume files are in test_directory. I had to fix several of those by running python foo.py, from within subset_tests_directory and correcting as needed.

  5. Once the test scripts execute correctly, just cd subset_tests_directory and pytest there. Pytest will only pick up the scripts it sees.

Another possibility is symlinking within your current test directory, say as ln -s foo.py subset_foo.py then pytest subset*.py. That would avoid needing to adjust your imports, but it would clutter things up until you removed the symlinks. Worked for me as well.

Python causing: IOError: [Errno 28] No space left on device: '../results/32766.html' on disk with lots of space

It turns out the best solution for me here was to just reformat the drive. Once reformatted all these problems were no longer problems.

C++ sorting and keeping track of indexes

There is another way to solve this, using a map:

vector<double> v = {...}; // input data
map<double, unsigned> m; // mapping from value to its index
for (auto it = v.begin(); it != v.end(); ++it)
    m[*it] = it - v.begin();

This will eradicate non-unique elements though. If that's not acceptable, use a multimap:

vector<double> v = {...}; // input data
multimap<double, unsigned> m; // mapping from value to its index
for (auto it = v.begin(); it != v.end(); ++it)
    m.insert(make_pair(*it, it - v.begin()));

In order to output the indices, iterate over the map or multimap:

for (auto it = m.begin(); it != m.end(); ++it)
    cout << it->second << endl;

How to filter by object property in angularJS

You can try this. its working for me 'name' is a property in arr.

repeat="item in (tagWordOptions | filter:{ name: $select.search } ) track by $index

Defining and using a variable in batch file

Consider also using SETX - it will set variable on user or machine (available for all users) level though the variable will be usable with the next opening of the cmd.exe ,so often it can be used together with SET :

::setting variable for the current user
if not defined My_Var (
  set "My_Var=My_Value"
  setx My_Var My_Value
)

::setting machine defined variable
if not defined Global_Var (
  set "Global_Var=Global_Value"
  SetX Global_Var Global_Value /m
)

You can also edit directly the registry values:

User Variables: HKEY_CURRENT_USER\Environment

System Variables: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

Which will allow to avoid some restrictions of SET and SETX like the variables containing = in their names.

How do you fix the "element not interactable" exception?

For those discovering this now and the above answers didn't work, the issue I had was the screen wasn't big enough. I added this when initializing my ChromeDriver, and it fixed the problem:

options.add_argument("window-size=1200x600")

Using jQuery's ajax method to retrieve images as a blob

If you need to handle error messages using jQuery.AJAX you will need to modify the xhr function so the responseType is not being modified when an error happens.

So you will have to modify the responseType to "blob" only if it is a successful call:

$.ajax({
    ...
    xhr: function() {
        var xhr = new XMLHttpRequest();
        xhr.onreadystatechange = function() {
            if (xhr.readyState == 2) {
                if (xhr.status == 200) {
                    xhr.responseType = "blob";
                } else {
                    xhr.responseType = "text";
                }
            }
        };
        return xhr;
    },
    ...
    error: function(xhr, textStatus, errorThrown) {
        // Here you are able now to access to the property "responseText"
        // as you have the type set to "text" instead of "blob".
        console.error(xhr.responseText);
    },
    success: function(data) {
        console.log(data); // Here is "blob" type
    }
});

Note

If you debug and place a breakpoint at the point right after setting the xhr.responseType to "blob" you can note that if you try to get the value for responseText you will get the following message:

The value is only accessible if the object's 'responseType' is '' or 'text' (was 'blob').

Changing an AIX password via script?

Just this

passwd <<EOF
oldpassword
newpassword
newpassword
EOF

Actual output from ubuntu machine (sorry no AIX available to me):

user@host:~$ passwd <<EOF
oldpassword
newpassword
newpassword
EOF

Changing password for user.
(current) UNIX password: Enter new UNIX password: Retype new UNIX password: 
passwd: password updated successfully
user@host:~$

How to get Android crash logs?

Here is a solution that can help you dump all the logs onto a text file

adb logcat -d > logs.txt

How can we store into an NSDictionary? What is the difference between NSDictionary and NSMutableDictionary?

The key difference: NSMutableDictionary can be modified in place, NSDictionary cannot. This is true for all the other NSMutable* classes in Cocoa. NSMutableDictionary is a subclass of NSDictionary, so everything you can do with NSDictionary you can do with both. However, NSMutableDictionary also adds complementary methods to modify things in place, such as the method setObject:forKey:.

You can convert between the two like this:

NSMutableDictionary *mutable = [[dict mutableCopy] autorelease];
NSDictionary *dict = [[mutable copy] autorelease]; 

Presumably you want to store data by writing it to a file. NSDictionary has a method to do this (which also works with NSMutableDictionary):

BOOL success = [dict writeToFile:@"/file/path" atomically:YES];

To read a dictionary from a file, there's a corresponding method:

NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:@"/file/path"];

If you want to read the file as an NSMutableDictionary, simply use:

NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithContentsOfFile:@"/file/path"];

Merge Cell values with PHPExcel - PHP

There is a specific method to do this:

$objPHPExcel->getActiveSheet()->mergeCells('A1:C1');

You can also use:

$objPHPExcel->setActiveSheetIndex(0)->mergeCells('A1:C1');

That should do the trick.

How to save .xlsx data to file as a blob

Here's my implementation using the fetch api. The server endpoint sends a stream of bytes and the client receives a byte array and creates a blob out of it. A .xlsx file will then be generated.

return fetch(fullUrlEndpoint, options)
  .then((res) => {
    if (!res.ok) {
      const responseStatusText = res.statusText
      const errorMessage = `${responseStatusText}`
      throw new Error(errorMessage);
    }
    return res.arrayBuffer();
  })
    .then((ab) => {
      // BE endpoint sends a readable stream of bytes
      const byteArray = new Uint8Array(ab);
      const a = window.document.createElement('a');
      a.href = window.URL.createObjectURL(
        new Blob([byteArray], {
          type:
            'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
        }),
      );
      a.download = `${fileName}.XLSX`;
      document.body.appendChild(a);
      a.click();
      document.body.removeChild(a);
    })
    .catch(error => {
      throw new Error('Error occurred:' + error);
    });

How to get a responsive button in bootstrap 3

I know this already has a marked answer, but I feel I have an improvement to it.

The marked answer is a bit misleading. He set a width to the button, which is not necessary, and set widths are not "responsive". To his defense, he mentions in a comment below it, that the width is not necessary and just an example.

One thing not mentioned here, is that the words may break in the middle of a word and look messed up.

My solution, forces the break to happen between words, a nice word wrap.

.btn-responsive {
    white-space: normal !important;
    word-wrap: break-word;
}

<a href="#" class="btn btn-primary btn-responsive">Click Here</a>

Error: EACCES: permission denied, access '/usr/local/lib/node_modules'

If you are running Linux(ie: Arch)

# npm -g install packageName

By default this command installs the package under /usr/lib/node_modules/npm and requires root privileges to do so.

To Allow user-wide installations

To allow global package installations for the current user, set the npm_config_prefix environment variable. This is used by both npm and yarn.

~/.profile
PATH="$HOME/.node_modules/bin:$PATH"
export npm_config_prefix=~/.node_modules

Re-login or source to update changes.

You can also specify the --prefix parameter for npm install. However, this is not recommended, since you'll need to add it every time you install a global package.

$ npm -g install packageName --prefix ~/.node_modules

So you dont have to chown folder permision

Maven: The packaging for this project did not assign a file to the build artifact

I have same issue. Error message for me is not complete. But in my case, I've added generation jar with sources. By placing this code in pom.xml:

<build> 
    <pluginManagement>
        <plugins>
            <plugin>
                <artifactId>maven-source-plugin</artifactId>
                <version>2.1.2</version>
                <executions>
                    <execution>
                        <phase>deploy</phase>
                        <goals>
                            <goal>jar</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </pluginManagement>
</build>

So in deploy phase I execute source:jar goal which produces jar with sources. And deploy ends with BUILD SUCCESS

MySQL - Make an existing Field Unique

This code is to solve our problem to set unique key for existing table

alter ignore table ioni_groups add unique (group_name);

How to set auto increment primary key in PostgreSQL?

If you want to use numbers in a sequence, define a new sequence with something like

CREATE SEQUENCE public.your_sequence
    INCREMENT 1
    START 1
    MINVALUE 1
;

and then alter the table to use the sequence for the id:

ALTER TABLE ONLY table ALTER COLUMN id SET DEFAULT nextval('your_sequence'::regclass);

SecurityError: Blocked a frame with origin from accessing a cross-origin frame

I experienced this error when trying to embed an iframe and then opening the site with Brave. The error went away when I changed to "Shields Down" for the site in question. Obviously, this is not a full solution, since anyone else visiting the site with Brave will run into the same issue. To actually resolve it I would need to do one of the other things listed on this page. But at least I now know where the problem lies.

How to check if dropdown is disabled?

Try following or check demo disabled and readonly

$('#dropUnit').is(':disabled') //Returns bool
$('#dropUnit').attr('readonly') == "readonly"  //If Condition

You can check jQuery FAQ .

PHP: Show yes/no confirmation dialog

Try this:

<td>
    <a onclick="return confirm(\'Are you sure?\');" href="'.base_url('category/delete_category/'.$row->category_id).'" class="btn btn-danger btn-sm"><i class="fa fa-trash"></i> Delete Coupon</a>
</td>

JPA Query.getResultList() - use in a generic way

If you need a more convenient way to access the results, it's possible to transform the result of an arbitrarily complex SQL query to a Java class with minimal hassle:

Query query = em.createNativeQuery("select 42 as age, 'Bob' as name from dual", 
        MyTest.class);
MyTest myTest = (MyTest) query.getResultList().get(0);
assertEquals("Bob", myTest.name);

The class needs to be declared an @Entity, which means you must ensure it has an unique @Id.

@Entity
class MyTest {
    @Id String name;
    int age;
}

How do we use runOnUiThread in Android?

thy this:

@UiThread
    public void logMsg(final String msg) {
        new Handler(Looper.getMainLooper()).post(new Runnable() {
            @Override
            public void run() {
                Log.d("UI thread", "I am the UI thread");


            }
        });
    }

How to make flexbox items the same size?

Im no expert with flex but I got there by setting the basis to 50% for the two items i was dealing with. Grow to 1 and shrink to 0.

Inline styling: flex: '1 0 50%',

How to use order by with union all in sql?

Select 'Shambhu' as ShambhuNewsFeed,Note as [News Fedd],NotificationId
from Notification with(nolock) where DesignationId=@Designation 
Union All 
Select 'Shambhu' as ShambhuNewsFeed,Note as [Notification],NotificationId
from Notification with(nolock) 
where DesignationId=@Designation 
order by NotificationId desc

How to click on hidden element in Selenium WebDriver?

If the <div> has id or name then you can use find_element_by_id or find_element_by_name

You can also try with class name, css and xpath

find_element_by_class_name
find_element_by_css_selector
find_element_by_xpath

executing shell command in background from script

For example you have a start program named run.sh to start it working at background do the following command line. ./run.sh &>/dev/null &

Access parent DataContext from DataTemplate

RelativeSource vs. ElementName

These two approaches can achieve the same result,

RelativeSource

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

This method looks for a control of a type Window (in this example) in the visual tree and when it finds it you basically can access it's DataContext using the Path=DataContext..... The Pros about this method is that you don't need to be tied to a name and it's kind of dynamic, however, changes made to your visual tree can affect this method and possibly break it.

ElementName

Binding="{Binding Path=DataContext.MyBindingProperty, ElementName=MyMainWindow}

This method referes to a solid static Name so as long as your scope can see it, you're fine.You should be sticking to your naming convention not to break this method of course.The approach is qute simple and all you need is to specify a Name="..." for your Window/UserControl.

Although all three types (RelativeSource, Source, ElementName) are capable of doing the same thing, but according to the following MSDN article, each one better be used in their own area of specialty.

How to: Specify the Binding Source

Find the brief description of each plus a link to a more details one in the table on the bottom of the page.

Error 6 (net::ERR_FILE_NOT_FOUND): The files c or directory could not be found

Big one I see that causes this is filename. If you have a SPACE then any number such as 'Site 2' the file path with look like something/Site%202/index.html This is because spaces or rendered as %20, and if another number is immediately following that it will try to read it as %202. Fix is you never use spaces in your filenames.

How to change btn color in Bootstrap

Here's my flavor without the loss of hover. I personally like it better than the standard bootstrap transitioning.

_x000D_
_x000D_
.btn-primary,_x000D_
.btn-primary:active,_x000D_
.btn-primary:visited {_x000D_
  background-color: #8064A2 !important;_x000D_
}_x000D_
_x000D_
.btn-primary:hover {_x000D_
  background-color: #594671 !important;_x000D_
  transition: all 1s ease;_x000D_
  -webkit-transition: all 1s ease;_x000D_
  -moz-transition: all 1s ease;_x000D_
  -o-transition: all 1s ease;_x000D_
  -ms-transition: all 1s ease;_x000D_
}
_x000D_
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css" rel="stylesheet" />_x000D_
<button class="btn btn-primary">Hover me!</button>
_x000D_
_x000D_
_x000D_

Call jQuery Ajax Request Each X Minutes

use jquery Every time Plugin .using this you can do ajax call for "X" time period

$("#select").everyTime(1000,function(i) {
//ajax call
}

you can also use setInterval

Finding all cycles in a directed graph

DFS c++ version for the pseudo-code in second floor's answer:

void findCircleUnit(int start, int v, bool* visited, vector<int>& path) {
    if(visited[v]) {
        if(v == start) {
            for(auto c : path)
                cout << c << " ";
            cout << endl;
            return;
        }
        else 
            return;
    }
    visited[v] = true;
    path.push_back(v);
    for(auto i : G[v])
        findCircleUnit(start, i, visited, path);
    visited[v] = false;
    path.pop_back();
}

Difference between "include" and "require" in php

You find the differences explained in the detailed PHP manual on the page of require:

require is identical to include except upon failure it will also produce a fatal E_COMPILE_ERROR level error. In other words, it will halt the script whereas include only emits a warning (E_WARNING) which allows the script to continue.

See @efritz's answer for an example

How to make a div 100% height of the browser window

There are a couple of CSS 3 measurement units called:

Viewport-Percentage (or Viewport-Relative) Lengths

What are Viewport-Percentage Lengths?

From the linked W3 Candidate Recommendation above:

The viewport-percentage lengths are relative to the size of the initial containing block. When the height or width of the initial containing block is changed, they are scaled accordingly.

These units are vh (viewport height), vw (viewport width), vmin (viewport minimum length) and vmax (viewport maximum length).

How can this be used to make a divider fill the height of the browser?

For this question, we can make use of vh: 1vh is equal to 1% of the viewport's height. That is to say, 100vh is equal to the height of the browser window, regardless of where the element is situated in the DOM tree:

HTML

<div></div>

CSS

div {
    height: 100vh;
}

This is literally all that's needed. Here is a JSFiddle example of this in use.

What browsers support these new units?

This is currently supported on all up-to-date major browsers apart from Opera Mini. Check out Can I use... for further support.

How can this be used with multiple columns?

In the case of the question at hand, featuring a left and a right divider, here is a JSFiddle example showing a two-column layout involving both vh and vw.

How is 100vh different to 100%?

Take this layout for example:

<body style="height:100%">
    <div style="height:200px">
        <p style="height:100%; display:block;">Hello, world!</p>
    </div>
</body>

The p tag here is set to 100% height, but because its containing div has 200 pixels height, 100% of 200 pixels becomes 200 pixels, not 100% of the body height. Using 100vh instead means that the p tag will be 100% height of the body regardless of the div height. Take a look at this accompanying JSFiddle to easily see the difference!

Maven 3 warnings about build.plugins.plugin.version

Run like:

  $ mvn help:describe -DartifactId=maven-war-plugin -DgroupId=org.apache.maven.plugins

for plug-in that have no version. You get output:

Name: Maven WAR Plugin
Description: Builds a Web Application Archive (WAR) file from the project
  output and its dependencies.
Group Id: org.apache.maven.plugins
Artifact Id: maven-war-plugin
Version: 2.2
Goal Prefix: war

Use version that shown in output.

UPDATE If you want to select among list of versions, use http://search.maven.org/ or http://mvnrepository.com/ Note that your favorite Java IDE must have Maven package search dialog. Just check docs.

SUPER UPDATE I also use:

$ mvn dependency:tree
$ mvn dependency:list
$ mvn dependency:resolve
$ mvn dependency:resolve-plugins  # <-- THIS

Recently I discover how to get latest version for plug-in (or library) so no longer needs for googling or visiting Maven Central:

$ mvn versions:display-dependency-updates
$ mvn versions:display-plugin-updates     # <-- THIS

MySQL - Rows to Columns

I'm sorry to say this and maybe I'm not solving your problem exactly but PostgreSQL is 10 years older than MySQL and is extremely advanced compared to MySQL and there's many ways to achieve this easily. Install PostgreSQL and execute this query

CREATE EXTENSION tablefunc;

then voila! And here's extensive documentation: PostgreSQL: Documentation: 9.1: tablefunc or this query

CREATE EXTENSION hstore;

then again voila! PostgreSQL: Documentation: 9.0: hstore

Linux command line howto accept pairing for bluetooth device without pin

follow steps (CentOs):

  1. bluetoothctl
  2. devices
  3. scan on
  4. pair 34:88:5D:51:5A:95 (34:88:5D:51:5A:95 is my device code,replace it with yours)
  5. trust 34:88:5D:51:5A:95
  6. connect 34:88:5D:51:5A:95

If you want more details https://www.youtube.com/watch?v=CB1E4Ir3AV4

Getting first and last day of the current month

An alternative way is to use DateTime.DaysInMonth to get the number of days in the current month as suggested by @Jade

Since we know the first day of the month will always 1 we can use it as default for the first day with the current Month & year as current.year,current.Month,1.

var now = DateTime.Now; // get the current DateTime 

//Get the number of days in the current month
int daysInMonth = DateTime.DaysInMonth (now.Year, now.Month); 
    
//First day of the month is always 1
var firstDay = new DateTime(now.Year,now.Month,1); 
    
//Last day will be similar to the number of days calculated above
var lastDay = new DateTime(now.Year,now.Month,daysInMonth);

//So
rdpStartDate.SelectedDate = firstDay;
rdpEndDate.SelectedDate = lastDay; 

Using crontab to execute script every minute and another every 24 hours

every minute:

* * * * * /path/to/php /var/www/html/a.php

every 24hours (every midnight):

0 0 * * * /path/to/php /var/www/html/reset.php

See this reference for how crontab works: http://adminschoice.com/crontab-quick-reference, and this handy tool to build cron jobx: http://www.htmlbasix.com/crontab.shtml

Error QApplication: no such file or directory

To start things off, the error QApplication: no such file or directory means your compiler was not able to find this header. It is not related to the linking process as you mentioned in the question.

The -I flag (uppercase i) is used to specify the include (headers) directory (which is what you need to do), while the -L flag is used to specify the libraries directory. The -l flag (lowercase L) is used to link your application with a specified library.

But you can use Qt to your advantage: Qt has a build system named qmake which makes things easier. For instance, when I want to compile main.cpp I create a main.pro file. For educational purposes, let's say this source code is a simple project that uses only QApplication and QDeclarativeView. An appropriate .pro file would be:

TEMPLATE += app
QT += gui declarative
SOURCES += main.cpp

Then, execute the qmake inside that directory to create the Makefile that will be used to compile your application, and finally execute make to get the job done.

On my system this make outputs:

g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_DECLARATIVE_LIB -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/opt/qt_47x/mkspecs/linux-g++ -I. -I/opt/qt_47x/include/QtCore -I/opt/qt_47x/include/QtGui -I/opt/qt_47x/include/QtDeclarative -I/opt/qt_47x/include -I/usr/X11R6/include -I. -o main.o main.cpp
g++ -Wl,-O1 -Wl,-rpath,/opt/qt_47x/lib -o main main.o -L/opt/qt_47x/lib -L/usr/X11R6/lib -lQtDeclarative -L/opt/qt_47x/lib -lQtScript -lQtSvg -L/usr/X11R6/lib -lQtSql -lQtXmlPatterns -lQtNetwork -lQtGui -lQtCore -lpthread

Note: I installed Qt in another directory --> /opt/qt_47x

Edit: Qt 5.x and later

Add QT += widgets to the .pro file and solve this problem.

import httplib ImportError: No module named httplib

I had this issue when I was trying to make my Docker container smaller. It was because I'd installed Python 2.7 with:

apt-get install -y --no-install-recommends python

And I should not have included the --no-install-recommends flag:

apt-get install -y python

django - get() returned more than one topic

In your Topic model you're allowing for more than one element to have the same topic field. You have created two with the same one already.

topic=models.TextField(verbose_name='Thema')

Now when trying to add a new learningObjective you seem to want to add it to only one Topic that matches what you're sending on the form. Since there's more than one with the same topic field get is finding 2, hence the exception.

You can either add the learningObjective to all Topics with that topic field:

for t in topic.objects.filter(topic=request.POST['Thema']):
    t.learningObjectivesTopic.add(neuesLernziel)

or restrict the Topic model to have a unique topic field and keep using get, but that might not be what you want.

How to write to an existing excel file without overwriting data (using pandas)?

With openpyxlversion 2.4.0 and pandasversion 0.19.2, the process @ski came up with gets a bit simpler:

import pandas
from openpyxl import load_workbook

with pandas.ExcelWriter('Masterfile.xlsx', engine='openpyxl') as writer:
    writer.book = load_workbook('Masterfile.xlsx')
    data_filtered.to_excel(writer, "Main", cols=['Diff1', 'Diff2'])
#That's it!

TypeScript: casting HTMLElement

Do not type cast. Never. Use type guards:

const e = document.getElementsByName("script")[0];
if (!(e instanceof HTMLScriptElement)) 
  throw new Error(`Expected e to be an HTMLScriptElement, was ${e && e.constructor && e.constructor.name || e}`);
// locally TypeScript now types e as an HTMLScriptElement, same as if you casted it.

Let the compiler do the work for you and get errors when your assumptions turn out wrong.

It may look overkill in this case, but it will help you a lot if you come back later and change the selector, like adding a class that is missing in the dom, for example.

Attempted to read or write protected memory

Microsoft also released a hotfix (July 2nd, 2007) to prevent the error "Attempted to read or write protected memory" that has been plaguing the .NET 2.0 platform for some time now. Look at http://support.microsoft.com/kb/923028 - not sure if it applies to you, but thought you might like to check it out.

FontAwesome icons not showing. Why?

I got the similar problem, Shows icons in square, tried as per the instructions specified here : https://fontawesome.com/how-to-use/on-the-web/setup/hosting-font-awesome-yourself

Resolved by using this reference in head section of html page

<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.13.0/css/all.css">

Why is Tkinter Entry's get function returning nothing?

A simple example without classes:

from tkinter import *    
master = Tk()

# Create this method before you create the entry
def return_entry(en):
    """Gets and prints the content of the entry"""
    content = entry.get()
    print(content)  

Label(master, text="Input: ").grid(row=0, sticky=W)

entry = Entry(master)
entry.grid(row=0, column=1)

# Connect the entry with the return button
entry.bind('<Return>', return_entry) 

mainloop()

How do I specify different layouts for portrait and landscape orientations?

You just have to put it under separate folders with different names depending on orientation and resolution, the device will automatically select the right one for its screen settings

More info here:

http://developer.android.com/guide/practices/screens_support.html

under "Resource directory qualifiers for screen size and density"

What's a good (free) visual merge tool for Git? (on windows)

I've also used Meld. It's written in python. There is an official installer for Windows that works well.

Install it and then set it as your default mergetool.

$ git config --global merge.tool "meld"
$ git config --global mergetool.meld.path "C:\Program Files (x86)\Meld\Meld.exe"

If using a GUI GIT client, try the following (instructions for SourceTree, adjust accordingly)

  • In SourceTree, go to Tools/Options/Diff
  • In External Diff Tool, choose Custom
  • Enter C:\Program Files (x86)\Meld\meld.exe in Diff Command and $LOCAL $REMOTE in Arguments
  • In Merge Tool, choose Custom
  • Enter C:\Program Files (x86)\Meld\meld.exe in Diff Command and $LOCAL $MERGED $REMOTE in Arguments

Django set field value after a form is initialized

If you want to do it within the form's __init__ method for some reason, you can manipulate the initial dict:

class MyForm(forms.Form):
    my_field = forms.CharField(max_length=255)

    def __init__(self, *args, **kwargs):
        super(MyForm, self).__init__(*args, **kwargs)
        self.initial['my_field'] = 'Initial value'

In OS X Lion, LANG is not set to UTF-8, how to fix it?

This is a headbreaker for a long time. I see now it's OSX.. i change it system-wide and it works perfect

When i add this the LANG in Centos6 and Fedora is also my preferred LANG. You can also "uncheck" export or set locale in terminal settings (OSX) /etc/profile

export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8

How to deploy ASP.NET webservice to IIS 7?

  1. rebuild project in VS
  2. copy project folder to iis folder, probably C:\inetpub\wwwroot\
  3. in iis manager (run>inetmgr) add website, point to folder, point application pool based on your .net
  4. add web service to created website, almost the same as 3.
  5. INSTALL ASP for windows 7 and .net 4.0: c:\windows\microsoft.net framework\v4.(some numbers)\regiis.exe -i
  6. check access to web service on your browser

Disabling and enabling a html input button

While not directly related to the question, if you hop onto this question looking to disable something other than the typical input elements button, input, textarea, the syntax won't work.

To disable a div or a span, use setAttribute

document.querySelector('#somedivorspan').setAttribute('disabled', true);

P.S: Gotcha, only call this if you intend to disable. A bug in chrome Version 83 causes this to always disable even when the second parameter is false.

Adding 'serial' to existing column in Postgres

You can also use START WITH to start a sequence from a particular point, although setval accomplishes the same thing, as in Euler's answer, eg,

SELECT MAX(a) + 1 FROM foo;
CREATE SEQUENCE foo_a_seq START WITH 12345; -- replace 12345 with max above
ALTER TABLE foo ALTER COLUMN a SET DEFAULT nextval('foo_a_seq');

What is SYSNAME data type in SQL Server?

Let me list a use case below. Hope it helps. Here I'm trying to find the Table Owner of the Table 'Stud_dtls' from the DB 'Students'. As Mikael mentioned, sysname could be used when there is a need for creating some dynamic sql which needs variables holding table names, column names and server names. Just thought of providing a simple example to supplement his point.

USE Students

DECLARE @TABLE_NAME sysname

SELECT @TABLE_NAME = 'Stud_dtls'

SELECT TABLE_SCHEMA 
  FROM INFORMATION_SCHEMA.Tables
 WHERE TABLE_NAME = @TABLE_NAME

Sharepoint: How do I filter a document library view to show the contents of a subfolder?

Have you thought about creating a view with 'Folder = Show all items without folders', that would get all your documents out of their folders and then perhaps you could create your filter(s) over that view.

Prevent flex items from overflowing a container

Your flex items have

flex: 0 0 200px; /* <aside> */
flex: 1 0 auto;  /* <article> */ 

That means:

  • The <aside> will start at 200px wide.

    Then it won't grow nor shrink.

  • The <article> will start at the width given by the content.

    Then, if there is available space, it will grow to cover it.

    Otherwise it won't shrink.

To prevent horizontal overflow, you can:

  • Use flex-basis: 0 and then let them grow with a positive flex-grow.
  • Use a positive flex-shrink to let them shrink if there isn't enough space.

To prevent vertical overflow, you can

  • Use min-height instead of height to allow the flex items grow more if necessary
  • Use overflow different than visible on the flex items
  • Use overflow different than visible on the flex container

For example,

_x000D_
_x000D_
main, aside, article {
  margin: 10px;
  border: solid 1px #000;
  border-bottom: 0;
  min-height: 50px; /* min-height instead of height */
}
main {
  display: flex;
}
aside {
  flex: 0 1 200px; /* Positive flex-shrink */
}
article {
  flex: 1 1 auto; /* Positive flex-shrink */
}
_x000D_
<main>
  <aside>x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x </aside>
  <article>don't let flex item overflow container.... y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y </article>
</main>
_x000D_
_x000D_
_x000D_

Force "portrait" orientation mode

Something to complement: I have updated an app recently, the previous was working in both landscape and portrait mode, and I want the updated version should work in portrait mode, so I added

android:screenOrientation="portrait"

to the corresponding activity, and it just crashed when I tested the update. Then I added

android:configChanges="orientation|keyboardHidden"

too, and it works.

Using CSS how to change only the 2nd column of a table

You can use the :nth-child pseudo class like this:

.countTable table table td:nth-child(2)

Note though, this won't work in older browsers (or IE), you'll need to give the cells a class or use javascript in that case.

How can I see if a Perl hash already has a certain key?

I would counsel against using if ($hash{$key}) since it will not do what you expect if the key exists but its value is zero or empty.

Why "net use * /delete" does not work but waits for confirmation in my PowerShell script?

Try this:

net use * /delete /y

The /y key makes it select Yes in prompt silently

Table header to stay fixed at the top when user scrolls it out of view with jQuery

I too experienced the same issues with the border formatting not being shown using entrophy's code but a few little fixes and now the table is expandable and displays all css styling rules you may add.

to css add:

#maintable{width: 100%}    

then here is the new javascript:

    function moveScroll(){
    var scroll = $(window).scrollTop();
    var anchor_top = $("#maintable").offset().top;
    var anchor_bottom = $("#bottom_anchor").offset().top;
    if (scroll > anchor_top && scroll < anchor_bottom) {
        clone_table = $("#clone");
        if(clone_table.length === 0) {          
            clone_table = $("#maintable").clone();
            clone_table.attr({id: "clone"})
            .css({
                position: "fixed",
                "pointer-events": "none",
                 top:0
            })
            .width($("#maintable").width());

            $("#table-container").append(clone_table);
            // dont hide the whole table or you lose border style & 
            // actively match the inline width to the #maintable width if the 
            // container holding the table (window, iframe, div) changes width          
            $("#clone").width($("#maintable").width());
            // only the clone thead remains visible
            $("#clone thead").css({
                visibility:"visible"
            });
            // clone tbody is hidden
            $("#clone tbody").css({
                visibility:"hidden"
            });
            // add support for a tfoot element
            // and hide its cloned version too
            var footEl = $("#clone tfoot");
            if(footEl.length){
                footEl.css({
                    visibility:"hidden"
                });
            }
        }
    } 
    else {
        $("#clone").remove();
    }
}
$(window).scroll(moveScroll);

Vim: insert the same characters across multiple lines

I would use a macro to record my actions and would then repeat it.

  1. Put your cursor on the first letter in name.
  2. Hit qq to start recording into the q buffer.
  3. Hit i to go into insert mode, type vector_, and then hit Esc to leave insert mode.
  4. Now hit 0 to go back to the beginning of the line.
  5. Now hit j to go down.
  6. Now hit q again to stop recording.

You now have a nice macro.

Type 3@q to execute your macro three times to do the rest of the lines.

Pandas: drop a level from a multi-level column index?

You could also achieve that by renaming the columns:

df.columns = ['a', 'b']

This involves a manual step but could be an option especially if you would eventually rename your data frame.

CSS flexbox vertically/horizontally center image WITHOUT explicitely defining parent height

Without explicitly defining the height I determined I need to apply the flex value to the parent and grandparent div elements...

<div style="display: flex;">
<div style="display: flex;">
 <img alt="No, he'll be an engineer." src="theknack.png" style="margin: auto;" />
</div>
</div>

If you're using a single element (e.g. dead-centered text in a single flex element) use the following:

align-items: center;
display: flex;
justify-content: center;

Binding IIS Express to an IP Address

Below are the complete changes I needed to make to run my x64 bit IIS application using IIS Express, so that it was accessible to a remote host:

iisexpress /config:"C:\Users\test-user\Documents\IISExpress\config\applicationhost.config" /site:MyWebSite
Starting IIS Express ...
Successfully registered URL "http://192.168.2.133:8080/" for site "MyWebSite" application "/"
Registration completed for site "MyWebSite"
IIS Express is running.
Enter 'Q' to stop IIS Express

The configuration file (applicationhost.config) had a section added as follows:

<sites>
  <site name="MyWebsite" id="2">
    <application path="/" applicationPool="Clr4IntegratedAppPool">
      <virtualDirectory path="/" physicalPath="C:\build\trunk\MyWebsite" />
    </application>
    <bindings>
      <binding protocol="http" bindingInformation=":8080:192.168.2.133" />
    </bindings>
  </site>

The 64 bit version of the .NET framework can be enabled as follows:

<globalModules>
    <!--
        <add name="ManagedEngine" image="%windir%\Microsoft.NET\Framework\v2.0.50727\webengine.dll" preCondition="integratedMode,runtimeVersionv2.0,bitness32" />
        <add name="ManagedEngineV4.0_32bit" image="%windir%\Microsoft.NET\Framework\v4.0.30319\webengine4.dll" preCondition="integratedMode,runtimeVersionv4.0,bitness32" />
    -->             
    <add name="ManagedEngine64" image="%windir%\Microsoft.NET\Framework64\v4.0.30319\webengine4.dll" preCondition="integratedMode,runtimeVersionv4.0,bitness64" />

Program to find largest and second largest number in array

Find your second largest number without using any String function:

int array[];//Input array
int firstLargest, secondLargest;
int minNumber = -1;//whatever smallest you want to add here
/*There should be more than two elements*/
if (array_size < 2)
{
    printf("Array is too small");
    return;
}

firstLargest = secondLargest = minNumber;
for (index = 0; index < array_size ; ++index)
{
    //Largest number check
    if (array[index] > first)
    {
        secondLargest = firstLargest;
        firstLargest = array[index];
    }

    //It may not larger than first but can be larger than second number
    else if (array[index] > secondLargest && array[index] != firstLargest)
{
        secondLargest = array[index];
}

//Finally you got your answer
if (secondLargest == minNumber)
{
    printf("No Second largest number");
}
else
{
    printf("Second Largest Number is %d", secondLargest);
}

Ruby class instance variable vs. class variable

Source

Availability to instance methods

  • Class instance variables are available only to class methods and not to instance methods.
  • Class variables are available to both instance methods and class methods.

Inheritability

  • Class instance variables are lost in the inheritance chain.
  • Class variables are not.
class Vars

  @class_ins_var = "class instance variable value"  #class instance variable
  @@class_var = "class variable value" #class  variable

  def self.class_method
    puts @class_ins_var
    puts @@class_var
  end

  def instance_method
    puts @class_ins_var
    puts @@class_var
  end
end

Vars.class_method

puts "see the difference"

obj = Vars.new

obj.instance_method

class VarsChild < Vars


end

VarsChild.class_method

"Submit is not a function" error in JavaScript

submit is not a function

means that you named your submit button or some other element submit. Rename the button to btnSubmit and your call will magically work.

When you name the button submit, you override the submit() function on the form.

Hibernate Criteria Query to get specific columns

You can use multiselect function for this.

   CriteriaBuilder cb=session.getCriteriaBuilder();
            CriteriaQuery<Object[]> cquery=cb.createQuery(Object[].class);
            Root<Car> root=cquery.from(User.class);
            cquery.multiselect(root.get("id"),root.get("Name"));
            Query<Object[]> q=session.createQuery(cquery);
            List<Object[]> list=q.getResultList();
            System.out.println("id        Name");
            for (Object[] objects : list) {
                System.out.println(objects[0]+"        "+objects[1]);
             }
            

This is supported by hibernate 5. createCriteria is deprecated in further version of hibernate. So you can use criteria builder instead.

estimating of testing effort as a percentage of development time

The only time I factor in extra time for testing is if I'm unfamiliar with the testing technology I'll be using (e.g. using Selenium tests for the first time). Then I factor in maybe 10-20% for getting up to speed on the tools and getting the test infrastructure in place.

Otherwise testing is just an innate part of development and doesn't warrant an extra estimate. In fact, I'd probably increase the estimate for code done without tests.

EDIT: Note that I'm usually writing code test-first. If I have to come in after the fact and write tests for existing code that's going to slow things down. I don't find that test-first development slows me down at all except for very exploratory (read: throw-away) coding.

Comparing floating point number to zero

No.

Equality is equality.

The function you wrote will not test two doubles for equality, as its name promises. It will only test if two doubles are "close enough" to each other.

If you really want to test two doubles for equality, use this one:

inline bool isEqual(double x, double y)
{
   return x == y;
}

Coding standards usually recommend against comparing two doubles for exact equality. But that is a different subject. If you actually want to compare two doubles for exact equality, x == y is the code you want.

10.000000000000001 is not equal to 10.0, no matter what they tell you.

An example of using exact equality is when a particular value of a double is used as a synonym of some special state, such as "pending calulation" or "no data available". This is possible only if the actual numeric values after that pending calculation are only a subset of the possible values of a double. The most typical particular case is when that value is nonnegative, and you use -1.0 as an (exact) representation of a "pending calculation" or "no data available". You could represent that with a constant:

const double NO_DATA = -1.0;

double myData = getSomeDataWhichIsAlwaysNonNegative(someParameters);

if (myData != NO_DATA)
{
    ...
}

How do I get a value of datetime.today() in Python that is "timezone aware"?

Here's a stdlib solution that works on both Python 2 and 3:

from datetime import datetime

now = datetime.now(utc) # Timezone-aware datetime.utcnow()
today = datetime(now.year, now.month, now.day, tzinfo=utc) # Midnight

where today is an aware datetime instance representing the beginning of the day (midnight) in UTC and utc is a tzinfo object (example from the documentation):

from datetime import tzinfo, timedelta

ZERO = timedelta(0)

class UTC(tzinfo):
    def utcoffset(self, dt):
        return ZERO

    def tzname(self, dt):
        return "UTC"

    def dst(self, dt):
        return ZERO

utc = UTC()

Related: performance comparison of several ways to get midnight (start of a day) for a given UTC time. Note: it is more complex, to get midnight for a time zone with a non-fixed UTC offset.

R multiple conditions in if statement

Read this thread R - boolean operators && and ||.

Basically, the & is vectorized, i.e. it acts on each element of the comparison returning a logical array with the same dimension as the input. && is not, returning a single logical.