Programs & Examples On #Project structuring

How can you determine a point is between two other points on a line segment?

Using a more geometric approach, calculate the following distances:

ab = sqrt((a.x-b.x)**2 + (a.y-b.y)**2)
ac = sqrt((a.x-c.x)**2 + (a.y-c.y)**2)
bc = sqrt((b.x-c.x)**2 + (b.y-c.y)**2)

and test whether ac+bc equals ab:

is_on_segment = abs(ac + bc - ab) < EPSILON

That's because there are three possibilities:

  • The 3 points form a triangle => ac+bc > ab
  • They are collinear and c is outside the ab segment => ac+bc > ab
  • They are collinear and c is inside the ab segment => ac+bc = ab

Tomcat 7 is not running on browser(http://localhost:8080/ )

Sometimes another software can be holding this door and it can be the cause of this conflict, try change the door on the server.xml.

How to send value attribute from radio button in PHP

The radio buttons are sent on form submit when they are checked only...

use isset() if true then its checked otherwise its not

Why doesn't java.io.File have a close method?

The javadoc of the File class describes the class as:

An abstract representation of file and directory pathnames.

File is only a representation of a pathname, with a few methods concerning the filesystem (like exists()) and directory handling but actual streaming input and output is done elsewhere. Streams can be opened and closed, files cannot.

(My personal opinion is that it's rather unfortunate that Sun then went on to create RandomAccessFile, causing much confusion with its inconsistent naming.)

How to load URL in UIWebView in Swift?

Swift 3

@IBOutlet weak var webview: UIWebView!
webview.loadRequest(URLRequest(url: URL(string: "https://www.yourvideo.com")!))

Why does viewWillAppear not get called when an app comes back from the background?

It's even easier with SwiftUI:

var body: some View {     
    Text("Hello World")
    .onReceive(NotificationCenter.default.publisher(for: UIApplication.willResignActiveNotification)) { _ in
        print("Moving to background!")
    }
    .onReceive(NotificationCenter.default.publisher(for: UIApplication.willEnterForegroundNotification)) { _ in
        print("Moving back to foreground!")
    }   
}

Define make variable at rule execution time

I dislike "Don't" answers, but... don't.

make's variables are global and are supposed to be evaluated during makefile's "parsing" stage, not during execution stage.

In this case, as long as the variable local to a single target, follow @nobar's answer and make it a shell variable.

Target-specific variables, too, are considered harmful by other make implementations: kati, Mozilla pymake. Because of them, a target can be built differently depending on if it's built standalone, or as a dependency of a parent target with a target-specific variable. And you won't know which way it was, because you don't know what is already built.

Recursively find all files newer than a given time

This is a bit circuitous because touch doesn't take a raw time_t value, but it should do the job pretty safely in a script. (The -r option to date is present in MacOS X; I've not double-checked GNU.) The 'time' variable could be avoided by writing the command substitution directly in the touch command line.

time=$(date -r 1312603983 '+%Y%m%d%H%M.%S')
marker=/tmp/marker.$$
trap "rm -f $marker; exit 1" 0 1 2 3 13 15
touch -t $time $marker
find . -type f -newer $marker
rm -f $marker
trap 0

How to get current language code with Swift?

Swift 4 & 5:

Locale.current.languageCode

What file uses .md extension and how should I edit them?

BBEdit will also display MD on the mac.

and here is a quicklook plugin to display them when you preview them.

Return a value of '1' a referenced cell is empty

P4 is the cell I test for:

=IF(ISBLANK(P4),1,0)

HTML input textbox with a width of 100% overflows table cells

You could use the CSS3 box-sizing property to include the external padding and border:

input[type="text"] {
     width: 100%; 
     box-sizing: border-box;
     -webkit-box-sizing:border-box;
     -moz-box-sizing: border-box;
}

Ubuntu: OpenJDK 8 - Unable to locate package

I was having the same issue and tried all of the solutions on this page but none of them did the trick.

What finally worked was adding the universe repo to my repo list. To do that run the following command

sudo add-apt-repository universe

After running the above command I was able to run

sudo apt install openjdk-8-jre

without an issue and the package was installed.

Hope this helps someone.

How to disable Excel's automatic cell reference change after copy/paste?

Haven't check in Excel, but this works in Libreoffice4:

The whole thing of address rewriting comes during consecutive
(a1) cut
(a2) paste

You need to interrupt the consecutiveness by putting something in-between:
(b1) cut
(b2) select some empty cells (more than 1) and drag(move) them
(b3) paste

Step (b2) is where the cell that is about to update itself stops the tracking. Quick and simple.

Center align "span" text inside a div

If you know the width of the span you could just stuff in a left margin.

Try this:

.center { text-align: center}
div.center span { display: table; }

Add the "center: class to your .

If you want some spans centered, but not others, replace the "div.center span" in your style sheet to a class (e.g "center-span") and add that class to the span.

How to remove leading and trailing spaces from a string

You can use:

  • String.TrimStart - Removes all leading occurrences of a set of characters specified in an array from the current String object.
  • String.TrimEnd - Removes all trailing occurrences of a set of characters specified in an array from the current String object.
  • String.Trim - combination of the two functions above

Usage:

string txt = "                   i am a string                                    ";
char[] charsToTrim = { ' ' };    
txt = txt.Trim(charsToTrim)); // txt = "i am a string"

EDIT:

txt = txt.Replace(" ", ""); // txt = "iamastring"   

@viewChild not working - cannot read property nativeElement of undefined

@ViewChild('keywords-input') keywordsInput; doesn't match id="keywords-input"

id="keywords-input"

should be instead a template variable:

#keywordsInput

Note that camel case should be used, since - is not allowed in template reference names.

@ViewChild() supports names of template variables as string:

@ViewChild('keywordsInput') keywordsInput;

or component or directive types:

@ViewChild(MyKeywordsInputComponent) keywordsInput;

See also https://stackoverflow.com/a/35209681/217408

Hint:
keywordsInput is not set before ngAfterViewInit() is called

What does "#include <iostream>" do?

That is a C++ standard library header file for input output streams. It includes functionality to read and write from streams. You only need to include it if you wish to use streams.

Must issue a STARTTLS command first

I also faced the same issue while I was building email notification application. you just need to add one line. Below one saved my day.

props.put("mail.smtp.starttls.enable", "true");

com.sun.mail.smtp.SMTPSendFailedException: 530 5.7.0 Must issue a STARTTLS command first. h13-v6sm10627790pgp.13 - gsmtp

at com.sun.mail.smtp.SMTPTransport.issueSendCommand(SMTPTransport.java:2108)
at com.sun.mail.smtp.SMTPTransport.mailFrom(SMTPTransport.java:1609)
at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1117)
at javax.mail.Transport.send0(Transport.java:195)
at javax.mail.Transport.send(Transport.java:124)
at com.smruti.email.EmailProject.EmailSend.main(EmailSend.java:99)

Hope this helps you.

App store link for "rate/review this app"

All above approaches are correct, but nowadays using SKStoreProductViewController leads to better user experience. To use it you need to do the following:

  • implement SKStoreProductViewControllerDelegate protocol in your app delegate
  • add required productViewControllerDidFinish method:

    - (void)productViewControllerDidFinish:(SKStoreProductViewController *)viewController {
      [viewController dismissViewControllerAnimated: YES completion: nil];
    }
    
  • Check if SKStoreProductViewController class is available and either show it or switch to the App Store:

    extern NSString* cAppleID; // must be defined somewhere...
    
    if ([SKStoreProductViewController class] != nil) {
      SKStoreProductViewController* skpvc = [[SKStoreProductViewController new] autorelease];
      skpvc.delegate = self;
      NSDictionary* dict = [NSDictionary dictionaryWithObject: cAppleID forKey: SKStoreProductParameterITunesItemIdentifier];
      [skpvc loadProductWithParameters: dict completionBlock: nil];
      [[self _viewController] presentViewController: skpvc animated: YES completion: nil];
    }
    else {
      static NSString* const iOS7AppStoreURLFormat = @"itms-apps://itunes.apple.com/app/id%@";
      static NSString* const iOSAppStoreURLFormat = @"itms-apps://itunes.apple.com/WebObjects/MZStore.woa/wa/viewContentsUserReviews?type=Purple+Software&id=%@";
      NSString* url = [[NSString alloc] initWithFormat: ([[UIDevice currentDevice].systemVersion floatValue] >= 7.0f) ? iOS7AppStoreURLFormat : iOSAppStoreURLFormat, cAppleID];
      [[UIApplication sharedApplication] openURL: [NSURL URLWithString: url]];
    }
    

CSS Pseudo-classes with inline styles

You could try https://hacss.io:

<a href="http://www.google.com" class=":hover{text-decoration:none;}">Google</a>

Demo

LaTeX package for syntax highlighting of code in various languages

I would use the minted package as mentioned from the developer Konrad Rudolph instead of the listing package. Here is why:

listing package

The listing package does not support colors by default. To use colors you would need to include the color package and define color-rules by yourself with the \lstset command as explained for matlab code here.

Also, the listing package doesn't work well with unicode, but you can fix those problems as explained here and here.

The following code

\documentclass{article}
\usepackage{listings}

\begin{document}
\begin{lstlisting}[language=html]
<html>
    <head>
        <title>Hello</title>
    </head>
    <body>Hello</body>
</html>
\end{lstlisting}
\end{document}

produces the following image:

enter image description here

minted package

The minted package supports colors, unicode and looks awesome. However, in order to use it, you need to have python 2.6 and pygments. In Ubuntu, you can check your python version in the terminal with

python --version

and you can install pygments with

sudo apt-get install python-pygments

Then, since minted makes calls to pygments, you need to compile it with -shell-escape like this

pdflatex -shell-escape yourfile.tex

If you use a latex editor like TexMaker or something, I would recommend to add a user-command, so that you can still compile it in the editor.

The following code

\documentclass{article}
\usepackage{minted}
\begin{document}

\begin{minted}{html}
    <!DOCTYPE html>
    <html>
       <head>
           <title>Hello</title>
       </head>

       <body>Hello</body>
    </html>
\end{minted}
\end{document}

produces the following image:

enter image description here

Concatenating date with a string in Excel

Thanks for the solution !

It works, but in a french Excel environment, you should apply something like

TEXTE(F2;"jj/mm/aaaa")

to get the date preserved as it is displayed in F2 cell, after concatenation. Best Regards

Error:Execution failed for task ':app:transformClassesWithDexForDebug' in android studio

i have tried this one and it worked for me. hope it works for others too.

  1. Open build.gradle module file
  2. downgrade you sdkversion from 25 to 24 or 23
  3. add 'multiDexEnabled true'
  4. comment this line : compile 'com.android.support:appcompat-v7:25.1.0' (if it's in 'dependencies')
  5. Sync your project and ready to go.

Here i have attached screenshot to explain things. Go through this steps

happy to help.

thanks.

How to get selected value from Dropdown list in JavaScript

It is working fine with me.

I have the following HTML:

<div>
    <select id="select1">
        <option value="1">test1</option>
        <option value="2" selected="selected">test2</option>
        <option value="3">test3</option>
    </select>
    <br/>
    <button onClick="GetSelectedItem('select1');">Get Selected Item</button>
</div>

And the following JavaScript:

function GetSelectedItem(el)
{
    var e = document.getElementById(el);
    var strSel = "The Value is: " + e.options[e.selectedIndex].value + " and text is: " + e.options[e.selectedIndex].text;
    alert(strSel);
}

See that you are using the right id. In case you are using it with ASP.NET, the id changes when rendered.

How to create a Multidimensional ArrayList in Java?

Once I required 2-D arrayList and I created using List and ArrayList and the code is as follows:

import java.util.*;

public class ArrayListMatrix {

    public static void main(String args[]){

        List<ArrayList<Integer>> a = new ArrayList<>();

        ArrayList<Integer> a1 = new ArrayList<Integer>();
        ArrayList<Integer> a2 = new ArrayList<Integer>();
        ArrayList<Integer> a3 = new ArrayList<Integer>();


        a1.add(1);
        a1.add(2);
        a1.add(3);

        a2.add(4);
        a2.add(5);
        a2.add(6);

        a3.add(7);
        a3.add(8);
        a3.add(9);

        a.add(a1);
        a.add(a2);
        a.add(a3);


        for(ArrayList obj:a){

            ArrayList<Integer> temp = obj;

            for(Integer job : temp){
                System.out.print(job+" ");
            }
            System.out.println();
        }
    }
}

Output:

1 2 3

4 5 6

7 8 9

Source : https://www.codepuran.com/java/2d-matrix-arraylist-collection-class-java/

What is the bower (and npm) version syntax?

In a nutshell, the syntax for Bower version numbers (and NPM's) is called SemVer, which is short for 'Semantic Versioning'. You can find documentation for the detailed syntax of SemVer as used in Bower and NPM on the API for the semver parser within Node/npm. You can learn more about the underlying spec (which does not mention ~ or other syntax details) at semver.org.

There's a super-handy visual semver calculator you can play with, making all of this much easier to grok and test.

SemVer isn't just a syntax! It has some pretty interesting things to say about the right ways to publish API's, which will help to understand what the syntax means. Crucially:

Once you identify your public API, you communicate changes to it with specific increments to your version number. Consider a version format of X.Y.Z (Major.Minor.Patch). Bug fixes not affecting the API increment the patch version, backwards compatible API additions/changes increment the minor version, and backwards incompatible API changes increment the major version.

So, your specific question about ~ relates to that Major.Minor.Patch schema. (As does the related caret operator ^.) You can use ~ to narrow the range of versions you're willing to accept to either:

  • subsequent patch-level changes to the same minor version ("bug fixes not affecting the API"), or:
  • subsequent minor-level changes to the same major version ("backwards compatible API additions/changes")

For example: to indicate you'll take any subsequent patch-level changes on the 1.2.x tree, starting with 1.2.0, but less than 1.3.0, you could use:

"angular": "~1.2"
  or:
"angular": "~1.2.0"

This also gets you the same results as using the .x syntax:

"angular": "1.2.x"

But, you can use the tilde/~ syntax to be even more specific: if you're only willing to accept patch-level changes starting with 1.2.4, but still less than 1.3.0, you'd use:

"angular": "~1.2.4"

Moving left, towards the major version, if you use...

"angular": "~1"

... it's the same as...

"angular": "1.x"
  or:
"angular": "^1.0.0"

...and matches any minor- or patch-level changes above 1.0.0, and less than 2.0:

Note that last variation above: it's called a 'caret range'. The caret looks an awful lot like a >, so you'd be excused for thinking it means "any version greater than 1.0.0". (I've certainly slipped on that.) Nope!

Caret ranges are basically used to say that you care only about the left-most significant digit - usually the major version - and that you'll permit any minor- or patch-level changes that don't affect that left-most digit. Yet, unlike a tilde range that specifies a major version, caret ranges let you specify a precise minor/patch starting point. So, while ^1.0.0 === ~1, a caret range such as ^1.2.3 lets you say you'll take any changes >=1.2.3 && <2.0.0. You couldn't do that with a tilde range.

That all seems confusing at first, when you look at it up-close. But zoom out for a sec, and think about it this way: the caret simply lets you say that you're most concerned about whatever significant digit is left-most. The tilde lets you say you're most concerned about whichever digit is right-most. The rest is detail.

It's the expressive power of the tilde and the caret that explains why people use them much more than the simpler .x syntax: they simply let you do more. That's why you'll see the tilde used often even where .x would serve. As an example, see npm itself: its own package.json file includes lots of dependencies in ~2.4.0 format, rather than the 2.4.x format it could use. By sticking to ~, the syntax is consistent all the way down a list of 70+ versioned dependencies, regardless of which beginning patch number is acceptable.

Anyway, there's still more to SemVer, but I won't try to detail it all here. Check it out on the node semver package's readme. And be sure to use the semantic versioning calculator while you're practicing and trying to get your head around how SemVer works.


RE: Non-Consecutive Version Numbers: OP's final question seems to be about specifying non-consecutive version numbers/ranges (if I have edited it fairly). Yes, you can do that, using the common double-pipe "or" operator: ||. Like so:

"angular": "1.2 <= 1.2.9 || >2.0.0"

How can you undo the last git add?

You can use

git reset

to undo the recently added local files

 git reset file_name

to undo the changes for a specific file

How to hide "Showing 1 of N Entries" with the dataTables.js library

You can remove it with the bInfo option (http://datatables.net/usage/features#bInfo)

   $('#example').dataTable({
       "bInfo" : false
   });

Update: Since Datatables 1.10.* this option can be used as info, bInfo still works in current nightly build (1.10.10).

Get unicode value of a character

You can do it for any Java char using the one liner here:

System.out.println( "\\u" + Integer.toHexString('÷' | 0x10000).substring(1) );

But it's only going to work for the Unicode characters up to Unicode 3.0, which is why I precised you could do it for any Java char.

Because Java was designed way before Unicode 3.1 came and hence Java's char primitive is inadequate to represent Unicode 3.1 and up: there's not a "one Unicode character to one Java char" mapping anymore (instead a monstrous hack is used).

So you really have to check your requirements here: do you need to support Java char or any possible Unicode character?

How to solve PHP error 'Notice: Array to string conversion in...'

You are using <input name='C[]' in your HTML. This creates an array in PHP when the form is sent.

You are using echo $_POST['C']; to echo that array - this will not work, but instead emit that notice and the word "Array".

Depending on what you did with the rest of the code, you should probably use echo $_POST['C'][0];

JAVA_HOME is set to an invalid directory:

I found this while googling the issue with android licences when installing Flutter.

For Linux, update Your ~/.bashrc (or other shell config) file by adding this line at the end:

JAVA_HOME=/usr/local/android-studio/jre

Note: I installed Android studio by following the official installation guide for Linux (link).

For Windows, use the android studio's path to the jre directory and update the environment variable with the right value.

Then, run flutter doctor --android-licenses and press y to review the licences which are not accepted. Press y for each of the licences. It will ask Accept? (y/N): at the end of the license file. After You accept all unaccepted licences, You should see:

All SDK package licenses accepted

onchange event for html.dropdownlist

You can try this if you are passing a value to the action method.

@Html.DropDownList("Sortby", new SelectListItem[] { new SelectListItem() { Text = "Newest to Oldest", Value = "0" }, new SelectListItem() { Text = "Oldest to Newest", Value = "1" }},new { onchange = "document.location.href = '/ControllerName/ActionName?id=' + this.options[this.selectedIndex].value;" })

Remove the query string in case of no parameter passing.

jQuery dialog popup

It's quite simple, first HTML must be added:

<div id="dialog"></div>

Then, it must be initialized:

<script type="text/javascript">
  jQuery( document ).ready( function() {
    jQuery( '#dialog' ).dialog( { 'autoOpen': false } );
  });
</script>

After this you can show it by code:

jQuery( '#dialog' ).dialog( 'open' );

Origin null is not allowed by Access-Control-Allow-Origin

Adding a bit to use Gokhan's solution for using:

--allow-file-access-from-files

Now you just need to append above text in Target text followed by a space. make sure you close all the instances of chrome browser after adding above property. Now restart chrome by the icon where you added this property. It should work for all.

Rotate a div using javascript

To rotate a DIV we can add some CSS that, well, rotates the DIV using CSS transform rotate.

To toggle the rotation we can keep a flag, a simple variable with a boolean value that tells us what way to rotate.

var rotated = false;

document.getElementById('button').onclick = function() {
    var div = document.getElementById('div'),
        deg = rotated ? 0 : 66;

    div.style.webkitTransform = 'rotate('+deg+'deg)'; 
    div.style.mozTransform    = 'rotate('+deg+'deg)'; 
    div.style.msTransform     = 'rotate('+deg+'deg)'; 
    div.style.oTransform      = 'rotate('+deg+'deg)'; 
    div.style.transform       = 'rotate('+deg+'deg)'; 

    rotated = !rotated;
}

_x000D_
_x000D_
var rotated = false;_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
    var div = document.getElementById('div'),_x000D_
        deg = rotated ? 0 : 66;_x000D_
_x000D_
    div.style.webkitTransform = 'rotate('+deg+'deg)'; _x000D_
    div.style.mozTransform    = 'rotate('+deg+'deg)'; _x000D_
    div.style.msTransform     = 'rotate('+deg+'deg)'; _x000D_
    div.style.oTransform      = 'rotate('+deg+'deg)'; _x000D_
    div.style.transform       = 'rotate('+deg+'deg)'; _x000D_
    _x000D_
    rotated = !rotated;_x000D_
}
_x000D_
#div {_x000D_
    position:relative; _x000D_
    height: 200px; _x000D_
    width: 200px; _x000D_
    margin: 30px;_x000D_
    background: red;_x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_

To add some animation to the rotation all we have to do is add CSS transitions

div {
    -webkit-transition: all 0.5s ease-in-out;
    -moz-transition: all 0.5s ease-in-out;
    -o-transition: all 0.5s ease-in-out;
    transition: all 0.5s ease-in-out;
}

_x000D_
_x000D_
var rotated = false;_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
    var div = document.getElementById('div'),_x000D_
        deg = rotated ? 0 : 66;_x000D_
_x000D_
    div.style.webkitTransform = 'rotate('+deg+'deg)'; _x000D_
    div.style.mozTransform    = 'rotate('+deg+'deg)'; _x000D_
    div.style.msTransform     = 'rotate('+deg+'deg)'; _x000D_
    div.style.oTransform      = 'rotate('+deg+'deg)'; _x000D_
    div.style.transform       = 'rotate('+deg+'deg)'; _x000D_
    _x000D_
    rotated = !rotated;_x000D_
}
_x000D_
#div {_x000D_
    position:relative; _x000D_
    height: 200px; _x000D_
    width: 200px; _x000D_
    margin: 30px;_x000D_
    background: red;_x000D_
    -webkit-transition: all 0.5s ease-in-out;_x000D_
    -moz-transition: all 0.5s ease-in-out;_x000D_
    -o-transition: all 0.5s ease-in-out;_x000D_
    transition: all 0.5s ease-in-out;_x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_

Another way to do it is using classes, and setting all the styles in a stylesheet, thus keeping them out of the javascript

document.getElementById('button').onclick = function() {
    document.getElementById('div').classList.toggle('rotated');
}

_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
    document.getElementById('div').classList.toggle('rotated');_x000D_
}
_x000D_
#div {_x000D_
    position:relative; _x000D_
    height: 200px; _x000D_
    width: 200px; _x000D_
    margin: 30px;_x000D_
    background: red;_x000D_
    -webkit-transition: all 0.5s ease-in-out;_x000D_
    -moz-transition: all 0.5s ease-in-out;_x000D_
    -o-transition: all 0.5s ease-in-out;_x000D_
    transition: all 0.5s ease-in-out;_x000D_
}_x000D_
_x000D_
#div.rotated {_x000D_
    -webkit-transform : rotate(66deg); _x000D_
    -moz-transform : rotate(66deg); _x000D_
    -ms-transform : rotate(66deg); _x000D_
    -o-transform : rotate(66deg); _x000D_
    transform : rotate(66deg); _x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_

PostgreSQL - max number of parameters in "IN" clause?

According to the source code located here, starting at line 850, PostgreSQL doesn't explicitly limit the number of arguments.

The following is a code comment from line 870:

/*
 * We try to generate a ScalarArrayOpExpr from IN/NOT IN, but this is only
 * possible if the inputs are all scalars (no RowExprs) and there is a
 * suitable array type available.  If not, we fall back to a boolean
 * condition tree with multiple copies of the lefthand expression.
 * Also, any IN-list items that contain Vars are handled as separate
 * boolean conditions, because that gives the planner more scope for
 * optimization on such clauses.
 *
 * First step: transform all the inputs, and detect whether any are
 * RowExprs or contain Vars.
 */

Split string in JavaScript and detect line break

Here's the final code I [OP] used. Probably not best practice, but it worked.

function wrapText(context, text, x, y, maxWidth, lineHeight) {

    var breaks = text.split('\n');
    var newLines = "";
    for(var i = 0; i < breaks.length; i ++){
      newLines = newLines + breaks[i] + ' breakLine ';
    }

    var words = newLines.split(' ');
    var line = '';
    console.log(words);
    for(var n = 0; n < words.length; n++) {
      if(words[n] != 'breakLine'){
        var testLine = line + words[n] + ' ';
        var metrics = context.measureText(testLine);
        var testWidth = metrics.width;
        if (testWidth > maxWidth && n > 0) {
          context.fillText(line, x, y);
          line = words[n] + ' ';
          y += lineHeight;
        }
        else {
          line = testLine;
        }
      }else{
          context.fillText(line, x, y);
          line = '';
          y += lineHeight;
      }
    }
    context.fillText(line, x, y);
  }

Why is synchronized block better than synchronized method?

Difference between synchronized block and synchronized method are following:

  1. synchronized block reduce scope of lock, but synchronized method's scope of lock is whole method.
  2. synchronized block has better performance as only the critical section is locked but synchronized method has poor performance than block.
  3. synchronized block provide granular control over lock but synchronized method lock either on current object represented by this or class level lock.
  4. synchronized block can throw NullPointerException but synchronized method doesn't throw.
  5. synchronized block: synchronized(this){}

    synchronized method: public synchronized void fun(){}

python location on mac osx

I checked a few similar discussions and found out the best way to locate all python2/python3 builds is:

which -a python python3

C# compiler error: "not all code paths return a value"

I also experienced this problem and found the easy solution to be

public string ReturnValues()
{
    string _var = ""; // Setting an innitial value

    if (.....)  // Looking at conditions
    {
        _var = "true"; // Re-assign the value of _var
    }

    return _var; // Return the value of var
}

This also works with other return types and gives the least amount of problems

The initial value I chose was a fall-back value and I was able to re-assign the value as many times as required.

Spring Boot + JPA : Column name annotation ignored

In my case, the annotation was on the getter() method instead of the field itself (ported from a legacy application).

Spring ignores the annotation in this case as well but doesn't complain. The solution was to move it to the field instead of the getter.

In MS DOS copying several files to one file

make sure you have mapped the y: drive, or copy all the files to local dir c:/local

c:/local> copy *.* c:/newfile.txt

PHP fopen() Error: failed to open stream: Permission denied

You may need to change the permissions as an administrator. Open up terminal on your Mac and then open the directory that markers.xml is located in. Then type:

sudo chmod 777 markers.xml

You may be prompted for a password. Also, it could be the directories that don't allow full access. I'm not familiar with WordPress, so you may have to change the permission of each directory moving upward to the mysite directory.

Equivalent to AssemblyInfo in dotnet core/csproj

You can always add your own AssemblyInfo.cs, which comes in handy for InternalsVisibleToAttribute, CLSCompliantAttribute and others that are not automatically generated.

Adding AssemblyInfo.cs to a Project

  1. In Solution Explorer, right click on <project name> > Add > New Folder.

Add New Folder

  1. Name the folder "Properties".

Name folder Properties

  1. Right click on the "Properties" folder, and click Add > New Item....

Add New Item

  1. Select "Class" and name it "AssemblyInfo.cs".

Name file AssemblyInfo.cs

Suppressing Auto-Generated Attributes

If you want to move your attributes back to AssemblyInfo.cs instead of having them auto-generated, you can suppress them in MSBuild as natemcmaster pointed out in his answer.

Write HTML file using Java

It really depends on the type of HTML file you're creating.

For such tasks, I use to create an object, serialize it to XML, then transform it with XSL. The pros of this approach are:

  • The strict separation between source code and HTML template,
  • The possibility to edit HTML without having to recompile the application,
  • The ability to serve different HTML in different cases based on the same XML, or even serve XML directly when needed (for a further deserialization for example),
  • The shorter amount of code to write.

The cons are:

  • You must know XSLT and know how to implement it in Java.
  • You must write XSLT (and it's torture for many developers).
  • When transforming XML to HTML with XSLT, some parts may be tricky. Few examples: <textarea/> tags (which make the page unusable), XML declaration (which can cause problems with IE), whitespace (with <pre></pre> tags etc.), HTML entities (&nbsp;), etc.
  • The performance will be reduced, since serialization to XML wastes lots of CPU resources and XSL transformation is very costly too.

Now, if your HTML is very short or very repetitive or if the HTML has a volatile structure which changes dynamically, this approach must not be taken in account. On the other hand, if you serve HTML files which have all a similar structure and you want to reduce the amount of Java code and use templates, this approach may work.

[Ljava.lang.Object; cannot be cast to

I've faced such an issue and dig tones of material. So, to avoid ugly iteration you can simply tune your hql:

You need to frame your query like this

select entity from Entity as entity where ...

Also check such case, it perfectly works for me:

public List<User> findByRole(String role) {

    Query query = sessionFactory.getCurrentSession().createQuery("select user from User user join user.userRoles where role_name=:role_name");
    query.setString("role_name", role);
    @SuppressWarnings("unchecked")
    List<User> users = (List<User>) query.list();
    return users;
}

So here we are extracting object from query, not a bunch of fields. Also it's looks much more pretty.

How to indent/format a selection of code in Visual Studio Code with Ctrl + Shift + F

I want to indent a specific section of code in Visual Studio Code:

  • Select the lines you want to indent, and
  • use Ctrl + ] to indent them.

If you want to format a section (instead of indent it):

  • Select the lines you want to format,
  • use Ctrl + K, Ctrl + F to format them.

Why won't bundler install JSON gem?

For me, some of the answers mentioned earlier were helpful from understanding point of view, but those didn't solve my problem.

So this is what I did to solve issue.

  • Modified gemfile.lock to update json (2.0.2) (Earlier, it was 1.8.3)
  • Check the Bundler version installed (Bundler -v command). I had version 1.12.5 installed
  • Install bundler version 1.11.2 (using gem install bundler -v '1.11.2')
  • Then run bundle install

How to enable C++11 in Qt Creator?

According to this site add

CONFIG += c++11

to your .pro file (see at the bottom of that web page). It requires Qt 5.


The other answers, suggesting

QMAKE_CXXFLAGS += -std=c++11 (or QMAKE_CXXFLAGS += -std=c++0x)

also work with Qt 4.8 and gcc / clang.

CSS Background Opacity

Just make sure to put width and height for the foreground the same with the background, or try to have top, bottom, left and right properties.

<style>
    .foreground, .background {
        position: absolute;
    }
    .foreground {
        z-index: 1;
    }
    .background {
        background-image: url(your/image/here.jpg);
        opacity: 0.4;
    }
</style>

<div class="foreground"></div>
<div class="background"></div>

What is the proper way to format a multi-line dict in Python?

Usually, if you have big python objects it's quite hard to format them. I personally prefer using some tools for that.

Here is python-beautifier - www.cleancss.com/python-beautify that instantly turns your data into customizable style.

How to execute a shell script in PHP?

You might have disabled the exec privileges, most of the LAMP packages have those disabled. Check your php.ini for this line:

disable_functions = exec

And remove the exec, shell_exec entries if there are there.

Good Luck!

javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found

OK, So I faced the same issue for my android app which have secured domain i.e. HTTPS,

These are the steps:

  1. You need SSL certificate file i.e. ".pem" file for your domain.
  2. put that file into the assets folder
  3. Just copy and paste this class in your project

public class SSlUtilsw {

public static SSLContext getSslContextForCertificateFile(Context context, String fileName){

    try {
        KeyStore keyStore = SSlUtilsw.getKeyStore(context, fileName);
        SSLContext sslContext = SSLContext.getInstance("SSL");
        TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
        trustManagerFactory.init(keyStore);
        sslContext.init(null,trustManagerFactory.getTrustManagers(),new SecureRandom());
        return sslContext;

    }catch (Exception e){
        String msg = "Error during creating SslContext for certificate from assets";
        e.printStackTrace();
        throw new RuntimeException(msg);
    }
}

public static KeyStore getKeyStore(Context context,String fileName){
    KeyStore keyStore = null;
    try {
        AssetManager assetManager=context.getAssets();
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        InputStream caInput=assetManager.open(fileName);
        Certificate ca;
        try {
            ca=cf.generateCertificate(caInput);

        }finally {
            caInput.close();
        }
        String keyStoreType=KeyStore.getDefaultType();
        keyStore=KeyStore.getInstance(keyStoreType);
        keyStore.load(null,null);
        keyStore.setCertificateEntry("ca",ca);
    } catch (CertificateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (KeyStoreException e) {
        e.printStackTrace();
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }
    return keyStore;
}}
  1. In your http client class of retrofit, add this

        val trustManagerFactory: TrustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm())
    trustManagerFactory.init(null as KeyStore?)
    val trustManagers: Array<TrustManager> = trustManagerFactory.trustManagers
    if (trustManagers.size != 1 || trustManagers[0] !is X509TrustManager) {
        throw IllegalStateException("Unexpected default trust managers:" + trustManagers.contentToString())
    }
    val trustManager = trustManagers[0] as X509TrustManager
    
    httpClient.sslSocketFactory(SSlUtils.getSslContextForCertificateFile(
            applicationContextHere, "yourcertificate.pem").socketFactory, trustManager)
    

And that's it.

Why is there no multiple inheritance in Java, but implementing multiple interfaces is allowed?

Take for example the case where Class A has a getSomething method and class B has a getSomething method and class C extends A and B. What would happen if someone called C.getSomething? There is no way to determine which method to call.

Interfaces basically just specify what methods a implementing class needs to contain. A class that implements multiple interfaces just means that class has to implement the methods from all those interfaces. Whci would not lead to any issues as described above.

Where is NuGet.Config file located in Visual Studio project?

If you use proxy, you will have to edit the Nuget.config file.

In Windows 7 and 10, this file is in the path:
C:\Users\YouUser\AppData\Roaming\NuGet.

Include the setting:

<config>
  <add key = "http_proxy" value = "http://Youproxy:8080" />
  <add key = "http_proxy.user" value = "YouProxyUser" />
</config>

mongodb/mongoose findMany - find all documents with IDs listed in array

Use this format of querying

let arr = _categories.map(ele => new mongoose.Types.ObjectId(ele.id));

Item.find({ vendorId: mongoose.Types.ObjectId(_vendorId) , status:'Active'})
  .where('category')
  .in(arr)
  .exec();

"Unable to acquire application service" error while launching Eclipse

For me, what eventually did the trick was adding -clean at the start of eclipse.ini

TypeError: 'function' object is not subscriptable - Python

You have two objects both named bank_holiday -- one a list and one a function. Disambiguate the two.

bank_holiday[month] is raising an error because Python thinks bank_holiday refers to the function (the last object bound to the name bank_holiday), whereas you probably intend it to mean the list.

What MySQL data type should be used for Latitude/Longitude with 8 decimal places?

Additionally, you will see that float values are rounded.

// e.g: given values 41.0473112,29.0077011

float(11,7) | decimal(11,7)
---------------------------
41.0473099  | 41.0473112
29.0077019  | 29.0077011

Rails: How does the respond_to block work?

From what I know, respond_to is a method attached to the ActionController, so you can use it in every single controller, because all of them inherits from the ActionController. Here is the Rails respond_to method:

def respond_to(&block)
  responder = Responder.new(self)
  block.call(responder)
  responder.respond
end

You are passing it a block, like I show here:

respond_to <<**BEGINNING OF THE BLOCK**>> do |format|
  format.html
  format.xml  { render :xml => @whatever }
end <<**END OF THE BLOCK**>>

The |format| part is the argument that the block is expecting, so inside the respond_to method we can use that. How?

Well, if you notice we pass the block with a prefixed & in the respond_to method, and we do that to treat that block as a Proc. Since the argument has the ".xml", ".html" we can use that as methods to be called.

What we basically do in the respond_to class is call methods ".html, .xml, .json" to an instance of a Responder class.

What is the difference between single and double quotes in SQL?

Single quotes delimit a string constant or a date/time constant.

Double quotes delimit identifiers for e.g. table names or column names. This is generally only necessary when your identifier doesn't fit the rules for simple identifiers.

See also:

You can make MySQL use double-quotes per the ANSI standard:

SET GLOBAL SQL_MODE=ANSI_QUOTES

You can make Microsoft SQL Server use double-quotes per the ANSI standard:

SET QUOTED_IDENTIFIER ON

Use Awk to extract substring

You just want to set the field separator as . using the -F option and print the first field:

$ echo aaa0.bbb.ccc | awk -F'.' '{print $1}'
aaa0

Same thing but using cut:

$ echo aaa0.bbb.ccc | cut -d'.' -f1
aaa0

Or with sed:

$ echo aaa0.bbb.ccc | sed 's/[.].*//'
aaa0

Even grep:

$ echo aaa0.bbb.ccc | grep -o '^[^.]*'
aaa0

How can I get the current date and time in the terminal and set a custom command in the terminal for it?

The command is date

To customise the output there are a myriad of options available, see date --help for a list.

For example, date '+%A %W %Y %X' gives Tuesday 34 2013 08:04:22 which is the name of the day of the week, the week number, the year and the time.

How to scroll to bottom in a ScrollView on activity startup

After initializing your UI component and fill it with data. add those line to your on create method

Runnable runnable=new Runnable() {
        @Override
        public void run() {
            scrollView.fullScroll(ScrollView.FOCUS_DOWN);
        }
    };
    scrollView.post(runnable);

String.equals() with multiple conditions (and one action on result)

No,its check like if string is "john" OR "mary" OR "peter" OR "etc."

you should check using ||

Like.,,if(str.equals("john") || str.equals("mary") || str.equals("peter"))

Print the address or pointer for value in C

Since you already seem to have solved the basic pointer address display, here's how you would check the address of a double pointer:

char **a;
char *b;
char c = 'H';

b = &c;
a = &b;

You would be able to access the address of the double pointer a by doing:

printf("a points at this memory location: %p", a);
printf("which points at this other memory location: %p", *a);

Android WebView progress bar

According to Md. Sajedul Karim answer I wrote a similar one.

webView = (WebView) view.findViewById(R.id.web);
progressBar = (ProgressBar) view.findViewById(R.id.progress);
webView.setWebChromeClient(new WebChromeClient());

setProgressBarVisibility(View.VISIBLE);
webView.setWebViewClient(new WebViewClient() {
    @Override
    public void onPageStarted(WebView view, String url, Bitmap favicon) {
        super.onPageStarted(view, url, favicon);
        setProgressBarVisibility(View.VISIBLE);
    }

    @Override
    public void onPageFinished(WebView view, String url) {
        super.onPageFinished(view, url);
        setProgressBarVisibility(View.GONE);
    }

    @Override
    public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
        super.onReceivedError(view, request, error);
        Toast.makeText(getActivity(), "Cannot load page", Toast.LENGTH_SHORT).show();
        setProgressBarVisibility(View.GONE);
    }
});

webView.loadUrl(url);

private void setProgressBarVisibility(int visibility) {
    // If a user returns back, a NPE may occur if WebView is still loading a page and then tries to hide a ProgressBar.
    if (progressBar != null) {
        progressBar.setVisibility(visibility);
    }
}

ASP.NET Core Dependency Injection error: Unable to resolve service for type while attempting to activate

I got this issue because of a rather silly mistake. I had forgotten to hook my service configuration procedure to discover controllers automatically in the ASP.NET Core application.

Adding this method solved it:

// Add framework services.
            services.AddMvc()
                    .AddControllersAsServices();      // <---- Super important

Matplotlib figure facecolor (background color)

If you want to change background color, try this:

plt.rcParams['figure.facecolor'] = 'white'

Search for one value in any column of any table inside a database

I found a fairly robust solution at https://gallery.technet.microsoft.com/scriptcenter/c0c57332-8624-48c0-b4c3-5b31fe641c58 , which I thought was worth pointing out. It searches columns of these types: varchar, char, nvarchar, nchar, text. It works great and supports specific table-searching as well as multiple search-terms.

Eclipse comment/uncomment shortcut?

In eclipse Pressing Ctrl + Shift + L, will list all the shortcuts.

initializing strings as null vs. empty string

There are no gotchas. The default construction of std::string is "". But you cannot compare a string to NULL. The closest you can get is to check whether the string is empty or not, using the std::string::empty method..

how to get value of selected item in autocomplete

When autocomplete changes a value, it fires a autocompletechange event, not the change event

$(document).ready(function () {
    $('#tags').on('autocompletechange change', function () {
        $('#tagsname').html('You selected: ' + this.value);
    }).change();
});

Demo: Fiddle

Another solution is to use select event, because the change event is triggered only when the input is blurred

$(document).ready(function () {
    $('#tags').on('change', function () {
        $('#tagsname').html('You selected: ' + this.value);
    }).change();
    $('#tags').on('autocompleteselect', function (e, ui) {
        $('#tagsname').html('You selected: ' + ui.item.value);
    });
});

Demo: Fiddle

How To Change DataType of a DataColumn in a DataTable?

Puedes agregar una columna con tipo de dato distinto , luego copiar los datos y eliminar la columna anterior

TB.Columns.Add("columna1", GetType(Integer))    
TB.Select("id=id").ToList().ForEach(Sub(row) row("columna1") = row("columna2"))    
TB.Columns.Remove("columna2")

Removing nan values from an array

This is my approach to filter ndarray "X" for NaNs and infs,

I create a map of rows without any NaN and any inf as follows:

idx = np.where((np.isnan(X)==False) & (np.isinf(X)==False))

idx is a tuple. It's second column (idx[1]) contains the indices of the array, where no NaN nor inf where found across the row.

Then:

filtered_X = X[idx[1]]

filtered_X contains X without NaN nor inf.

Checkout remote branch using git svn

Standard Subversion layout

Create a git clone of that includes your Subversion trunk, tags, and branches with

git svn clone http://svn.example.com/project -T trunk -b branches -t tags

The --stdlayout option is a nice shortcut if your Subversion repository uses the typical structure:

git svn clone http://svn.example.com/project --stdlayout

Make your git repository ignore everything the subversion repo does:

git svn show-ignore >> .git/info/exclude

You should now be able to see all the Subversion branches on the git side:

git branch -r

Say the name of the branch in Subversion is waldo. On the git side, you'd run

git checkout -b waldo-svn remotes/waldo

The -svn suffix is to avoid warnings of the form

warning: refname 'waldo' is ambiguous.

To update the git branch waldo-svn, run

git checkout waldo-svn
git svn rebase

Starting from a trunk-only checkout

To add a Subversion branch to a trunk-only clone, modify your git repository's .git/config to contain

[svn-remote "svn-mybranch"]
        url = http://svn.example.com/project/branches/mybranch
        fetch = :refs/remotes/mybranch

You'll need to develop the habit of running

git svn fetch --fetch-all

to update all of what git svn thinks are separate remotes. At this point, you can create and track branches as above. For example, to create a git branch that corresponds to mybranch, run

git checkout -b mybranch-svn remotes/mybranch

For the branches from which you intend to git svn dcommit, keep their histories linear!


Further information

You may also be interested in reading an answer to a related question.

How do I mock a service that returns promise in AngularJS Jasmine unit test?

Honestly.. you are going about this the wrong way by relying on inject to mock a service instead of module. Also, calling inject in a beforeEach is an anti-pattern as it makes mocking difficult on a per test basis.

Here is how I would do this...

module(function ($provide) {
  // By using a decorator we can access $q and stub our method with a promise.
  $provide.decorator('myOtherService', function ($delegate, $q) {

    $delegate.makeRemoteCallReturningPromise = function () {
      var dfd = $q.defer();
      dfd.resolve('some value');
      return dfd.promise;
    };
  });
});

Now when you inject your service it will have a properly mocked method for usage.

Store a cmdlet's result value in a variable in Powershell

Use the -ExpandProperty flag of Select-Object

$var=Get-WSManInstance -enumerate wmicimv2/win32_process | select -expand Priority

Update to answer the other question:

Note that you can as well just access the property:

$var=(Get-WSManInstance -enumerate wmicimv2/win32_process).Priority

So to get multiple of these into variables:

$var=Get-WSManInstance -enumerate wmicimv2/win32_process
   $prio = $var.Priority
   $pid = $var.ProcessID

How to configure the web.config to allow requests of any length

Add the following to your web.config:

<system.webServer>
  <security>
    <requestFiltering>
      <requestLimits maxQueryString="32768"/>
    </requestFiltering>
  </security>
</system.webServer>

See:

http://www.iis.net/ConfigReference/system.webServer/security/requestFiltering/requestLimits

Updated to reflect comments.

requestLimits Element for requestFiltering [IIS Settings Schema]

You may have to add the following in your web.config as well

<system.web>
    <httpRuntime maxQueryStringLength="32768" maxUrlLength="65536"/>
</system.web>

See: httpRuntime Element (ASP.NET Settings Schema)

Of course the numbers (32768 and 65536) in the config settings above are just examples. You don't have to use those exact values.

undefined reference to boost::system::system_category() when compiling

When I had this, problem, the cause was the ordering of the libraries. To fix it, I put libboost_system last:

g++ mingw/timer1.o -o mingw/timer1.exe  -L/usr/local/boost_1_61_0/stage/lib \
    -lboost_timer-mgw53-mt-1_61 \
    -lboost_chrono-mgw53-mt-1_61 \
    -lboost_system-mgw53-mt-1_61

This was on mingw with gcc 5.3 and boost 1.61.0 with a simple timer example.

How to Set a Custom Font in the ActionBar Title?

use new toolbar in support library design your actionbar as your own or use below code

Inflating Textview is not an good option try Spannable String builder

Typeface font2 = Typeface.createFromAsset(getAssets(), "fonts/<your font in assets folder>");   
SpannableStringBuilder SS = new SpannableStringBuilder("MY Actionbar Tittle");
SS.setSpan (new CustomTypefaceSpan("", font2), 0, SS.length(),Spanned.SPAN_EXCLUSIVE_INCLUSIVE);
actionBar.setTitle(ss);

copy below class

public class CustomTypefaceSpan extends TypefaceSpan{

    private final Typeface newType;

    public CustomTypefaceSpan(String family, Typeface type) {
        super(family);
        newType = type;
    }

    @Override
    public void updateDrawState(TextPaint ds) {
        applyCustomTypeFace(ds, newType);
    }

    @Override
    public void updateMeasureState(TextPaint paint) {
        applyCustomTypeFace(paint, newType);
    }

    private static void applyCustomTypeFace(Paint paint, Typeface tf) {
        int oldStyle;
        Typeface old = paint.getTypeface();
        if (old == null) {
            oldStyle = 0;
        } else {
            oldStyle = old.getStyle();
        }

        int fake = oldStyle & ~tf.getStyle();
        if ((fake & Typeface.BOLD) != 0) {
            paint.setFakeBoldText(true);
        }

        if ((fake & Typeface.ITALIC) != 0) {
            paint.setTextSkewX(-0.25f);
        }

        paint.setTypeface(tf);
    }

}

Converting an integer to a hexadecimal string in Ruby

To summarize:

p 10.to_s(16) #=> "a"
p "%x" % 10 #=> "a"
p "%02X" % 10 #=> "0A"
p sprintf("%02X", 10) #=> "0A"
p "#%02X%02X%02X" % [255, 0, 10] #=> "#FF000A"

Find files in a folder using Java

As of Java 1.8, you can use Files.list to get a stream:

Path findFile(Path targetDir, String fileName) throws IOException {
    return Files.list(targetDir).filter( (p) -> {
        if (Files.isRegularFile(p)) {
            return p.getFileName().toString().equals(fileName);
        } else {
            return false;
        }
    }).findFirst().orElse(null);
}

Python: How do I make a subclass from a superclass?

There is another way to make subclasses in python dynamically with a function type():

SubClass = type('SubClass', (BaseClass,), {'set_x': set_x})  # Methods can be set, including __init__()

You usually want to use this method when working with metaclasses. When you want to do some lower level automations, that alters way how python creates class. Most likely you will not ever need to do it in this way, but when you do, than you already will know what you are doing.

Bootstrap modal opening on page load

Use a document.ready() event around your call.

$(document).ready(function () {

    $('#memberModal').modal('show');

});

jsFiddle updated - http://jsfiddle.net/uvnggL8w/1/

How to print object array in JavaScript?

You can just use the following syntax and the object will be fully shown in the console:

console.log('object evt: %O', object);

I use Chrome browser don't know if this is adaptable for other browsers.

How schedule build in Jenkins?

Try this for 4 PM from Monday to Sunday

0 16 * * *

You can check the description messgage displayed while you configuring in "Build periodically' under Jenkins. (Refer the screenshot given below)

"Would last have run at Sunday, November 17, 2019 4:00:05 PM IST; would next run at Monday, November 18, 2019 4:00:05 PM IST."

Screenshot

enter image description here

The seconds in the time " Monday, November 18, 2019 4:00:05 PM IST" refers to our current system seconds.

Access a URL and read Data with R

scan can read from a web page automatically; you don't necessarily have to mess with connections.

Default background color of SVG root element

I'm currently working on a file like this:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<?xml-stylesheet type="text/css" href="style.css" ?>
<svg
  xmlns="http://www.w3.org/2000/svg"
  version="1.1"
  width="100%"
  height="100%"
  viewBox="0 0 600 600">
...

And I tried to put this into style.css:

svg {
  background: #bf1f1f;
}

It's working on Chromium and Firefox, but I don't think that it's a good practice. EyeOfGnome image viewer doesn't render it, and Inkscape uses a special namespace to store such a background:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
    xmlns="http://www.w3.org/2000/svg"
    xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
    version="1.1"
    ...
  <sodipodi:namedview
     pagecolor="#480000" ... >

Well, it seems that SVG root element is not part of paintable elements in SVG recommandations.

So I'd suggest to use the "rect" solution provided by Robert Longson because I guess that it is not a simple "hack". It seems to be the standard way to set a background with SVG.

Angular2 change detection: ngOnChanges not firing for nested object

Here's an example using IterableDiffer with ngDoCheck. IterableDiffer is especially useful if you need to track changes over time as it lets you do things like iterate over only added/changed/removed values etc.

A simple example not using all advantages of IterableDiffer, but it works and shows the principle:

export class FeedbackMessagesComponent implements DoCheck {
  @Input()
  messages: UserFeedback[] = [];
  // Example UserFeedback instance { message = 'Ooops', type = Notice }

  @HostBinding('style.display')
  display = 'none';

  private _iterableDiffer: IterableDiffer<UserFeedback>;

  constructor(private _iterableDiffers: IterableDiffers) {
    this._iterableDiffer = this._iterableDiffers.find([]).create(null);
  }

  ngDoCheck(): void {
    const changes = this._iterableDiffer.diff(this.messages);

    if (changes) {
      // Here you can do stuff like changes.forEachRemovedItem()

      // We know contents of this.messages was changed so update visibility:
      this.display = this.messages.length > 0 ? 'block' : 'none';
    }
  }
}

This will now automatically show/hide depending on myMessagesArray count:

_x000D_
_x000D_
<app-feedback-messages
  [messages]="myMessagesArray"
></app-feedback-messages>
_x000D_
_x000D_
_x000D_

How to convert a file to utf-8 in Python?

To guess what's the source encoding you can use the file *nix command.

Example:

$ file --mime jumper.xml

jumper.xml: application/xml; charset=utf-8

What are passive event listeners?

Passive event listeners are an emerging web standard, new feature shipped in Chrome 51 that provide a major potential boost to scroll performance. Chrome Release Notes.

It enables developers to opt-in to better scroll performance by eliminating the need for scrolling to block on touch and wheel event listeners.

Problem: All modern browsers have a threaded scrolling feature to permit scrolling to run smoothly even when expensive JavaScript is running, but this optimization is partially defeated by the need to wait for the results of any touchstart and touchmove handlers, which may prevent the scroll entirely by calling preventDefault() on the event.

Solution: {passive: true}

By marking a touch or wheel listener as passive, the developer is promising the handler won't call preventDefault to disable scrolling. This frees the browser up to respond to scrolling immediately without waiting for JavaScript, thus ensuring a reliably smooth scrolling experience for the user.

document.addEventListener("touchstart", function(e) {
    console.log(e.defaultPrevented);  // will be false
    e.preventDefault();   // does nothing since the listener is passive
    console.log(e.defaultPrevented);  // still false
}, Modernizr.passiveeventlisteners ? {passive: true} : false);

DOM Spec , Demo Video , Explainer Doc

MySQL: Delete all rows older than 10 minutes

The answer is right in the MYSQL manual itself.

"DELETE FROM `table_name` WHERE `time_col` < ADDDATE(NOW(), INTERVAL -1 HOUR)"

Python SQLite: database is locked

Turned out the problem happened because the path to the db file was actually a samba mounted dir. I moved it and that started working.

convert string into array of integers

A quick one for modern browsers:

'14 2'.split(' ').map(Number);

// [14, 2]`

Please run `npm cache clean`

This error can be due to many many things.

The key here seems the hint about error reading. I see you are working on a flash drive or something similar? Try to run the install on a local folder owned by your current user.

You could also try with sudo, that might solve a permission problem if that's the case.

Another reason why it cannot read could be because it has not downloaded correctly, or saved correctly. A little problem in your network could have caused that, and the cache clean would remove the files and force a refetch but that does not solve your problem. That means it would be more on the save part, maybe it didn't save because of permissions, maybe it didn't not save correctly because it was lacking disk space...

How to hide code from cells in ipython notebook visualized with nbviewer?

jupyter nbconvert yourNotebook.ipynb --no-input --no-prompt

jupyter nbconvert yourNotebook.ipynb This part of the code will take the latex file format of the jupyter notebook and converts it to a html

--no-input This is like a parameter we are saying during conversion that dont add any inputs : here the input to a cell is the code.. so we hide it

--no-prompt Here also we are saying, During conversion dont show any prompts form the code like errors or warnings in the final HTML file ) so that that html will have only the Text and the code output in the form of a report !!..

Hope it helps :)

Getting an element from a Set

With Java 8 you can do:

Foo foo = set.stream().filter(item->item.equals(theItemYouAreLookingFor)).findFirst().get();

But be careful, .get() throws a NoSuchElementException, or you can manipulate a Optional item.

Can linux cat command be used for writing text to file?

cat can also be used following a | to write to a file, i.e. pipe feeds cat a stream of data

Does `anaconda` create a separate PYTHONPATH variable for each new environment?

Anaconda does not use the PYTHONPATH. One should however note that if the PYTHONPATH is set it could be used to load a library that is not in the anaconda environment. That is why before activating an environment it might be good to do a

unset PYTHONPATH

For instance this PYTHONPATH points to an incorrect pandas lib:

export PYTHONPATH=/home/john/share/usr/anaconda/lib/python
source activate anaconda-2.7
python
>>>> import pandas as pd
/home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/hashtable.so: undefined symbol: PyUnicodeUCS2_DecodeUTF8
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/__init__.py", line 6, in <module>
    from . import hashtable, tslib, lib
ImportError: /home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/hashtable.so: undefined symbol: PyUnicodeUCS2_DecodeUTF8

unsetting the PYTHONPATH prevents the wrong pandas lib from being loaded:

unset PYTHONPATH
source activate anaconda-2.7
python
>>>> import pandas as pd
>>>>

How to set HTTP header to UTF-8 using PHP which is valid in W3C validator?

For a correct implementation, you need to change a series of things.

Database (immediately after the connection):

mysql_query("SET NAMES utf8");

// Meta tag HTML (probably it's already set): 
meta charset="utf-8"
header php (before any output of the HTML):
header('Content-Type: text/html; charset=utf-8')
table-rows-charset (for each row):
utf8_unicode_ci

TNS Protocol adapter error while starting Oracle SQL*Plus

Try typing all of this on the command line:

sqlplus / as sysdba

As what you are doing is starting sqlplus and then using sys as sysdba as the user-name which is incorrect as that is not a valid user. By using the above command Oracle is using your system login credentials to access the db. Also, I would confirm that the sqlplus executable you are running is the correct one by checking your path - ensure it is in the bin of the server installation directories.

PHP: How to handle <![CDATA[ with SimpleXMLElement?

This is working perfect for me.

$content = simplexml_load_string(
    $raw_xml
    , null
    , LIBXML_NOCDATA
);

Command to get nth line of STDOUT

You can use awk:

ls -l | awk 'NR==2'

Update

The above code will not get what we want because of off-by-one error: the ls -l command's first line is the total line. For that, the following revised code will work:

ls -l | awk 'NR==3'

What is the equivalent to a JavaScript setInterval/setTimeout in Android/Java?

import java.util.Timer;
import java.util.TimerTask;

class Clock {
    private Timer mTimer = new Timer();

    private int mSecondsPassed = 0;
    private TimerTask mTask = new TimerTask() {
        @Override
        public void run() {
            mSecondsPassed++;
            System.out.println("Seconds passed: " + mSecondsPassed);
        }
    };

    private void start() {
        mTimer.scheduleAtFixedRate(mTask, 1000, 1000);
    }

    public static void main(String[] args) {
        Clock c = new Clock();
        c.start();
    }
}

Python: Binary To Decimal Conversion

You can use int casting which allows the base specification.

int(b, 2)  # Convert a binary string to a decimal int.

How can I suppress column header output for a single SQL statement?

Invoke mysql with the -N (the alias for -N is --skip-column-names) option:

mysql -N ...
use testdb;
select * from names;

+------+-------+
|    1 | pete  |
|    2 | john  |
|    3 | mike  |
+------+-------+
3 rows in set (0.00 sec)

Credit to ErichBSchulz for pointing out the -N alias.

To remove the grid (the vertical and horizontal lines) around the results use -s (--silent). Columns are separated with a TAB character.

mysql -s ...
use testdb;
select * from names;

id  name
1   pete
2   john
3   mike

To output the data with no headers and no grid just use both -s and -N.

mysql -sN ...

Explicitly calling return in a function or not

It seems that without return() it's faster...

library(rbenchmark)
x <- 1
foo <- function(value) {
  return(value)
}
fuu <- function(value) {
  value
}
benchmark(foo(x),fuu(x),replications=1e7)
    test replications elapsed relative user.self sys.self user.child sys.child
1 foo(x)     10000000   51.36 1.185322     51.11     0.11          0         0
2 fuu(x)     10000000   43.33 1.000000     42.97     0.05          0         0

____EDIT __________________

I proceed to others benchmark (benchmark(fuu(x),foo(x),replications=1e7)) and the result is reversed... I'll try on a server.

What is the difference between SessionState and ViewState?

Session State contains information that is pertaining to a specific session (by a particular client/browser/machine) with the server. It's a way to track what the user is doing on the site.. across multiple pages...amid the statelessness of the Web. e.g. the contents of a particular user's shopping cart is session data. Cookies can be used for session state.
View State on the other hand is information specific to particular web page. It is stored in a hidden field so that it isn't visible to the user. It is used to maintain the user's illusion that the page remembers what he did on it the last time - dont give him a clean page every time he posts back. Check this page for more.

Cannot open include file 'afxres.h' in VC2010 Express

This header is a part of the MFC Library. VS Express edition doesn't contain MFC. If your project doesn't use MFC you can safely replace afxres.h with windows.h in your terrain2.rc.

Laravel password validation rule

I have had a similar scenario in Laravel and solved it in the following way.

The password contains characters from at least three of the following five categories:

  • English uppercase characters (A – Z)
  • English lowercase characters (a – z)
  • Base 10 digits (0 – 9)
  • Non-alphanumeric (For example: !, $, #, or %)
  • Unicode characters

First, we need to create a regular expression and validate it.

Your regular expression would look like this:

^.*(?=.{3,})(?=.*[a-zA-Z])(?=.*[0-9])(?=.*[\d\x])(?=.*[!$#%]).*$

I have tested and validated it on this site. Yet, perform your own in your own manner and adjust accordingly. This is only an example of regex, you can manipluated the way you want.

So your final Laravel code should be like this:

'password' => 'required|
               min:6|
               regex:/^.*(?=.{3,})(?=.*[a-zA-Z])(?=.*[0-9])(?=.*[\d\x])(?=.*[!$#%]).*$/|
               confirmed',

Update As @NikK in the comment mentions, in Laravel 5.5 and newer the the password value should encapsulated in array Square brackets like

'password' => ['required', 
               'min:6', 
               'regex:/^.*(?=.{3,})(?=.*[a-zA-Z])(?=.*[0-9])(?=.*[\d\x])(?=.*[!$#%]).*$/', 
               'confirmed']

I have not testing it on Laravel 5.5 so I am trusting @NikK hence I have moved to working with c#/.net these days and have no much time for Laravel.

Note:

  1. I have tested and validated it on both the regular expression site and a Laravel 5 test environment and it works.
  2. I have used min:6, this is optional but it is always a good practice to have a security policy that reflects different aspects, one of which is minimum password length.
  3. I suggest you to use password confirmed to ensure user typing correct password.
  4. Within the 6 characters our regex should contain at least 3 of a-z or A-Z and number and special character.
  5. Always test your code in a test environment before moving to production.
  6. Update: What I have done in this answer is just example of regex password

Some online references

Regarding your custom validation message for the regex rule in Laravel, here are a few links to look at:

Simple prime number generator in Python

If you wanted to find all the primes in a range you could do this:

def is_prime(num):
"""Returns True if the number is prime
else False."""
if num == 0 or num == 1:
    return False
for x in range(2, num):
    if num % x == 0:
        return False
else:
    return True
num = 0
itr = 0
tot = ''
while itr <= 100:
    itr = itr + 1
    num = num + 1
    if is_prime(num) == True:
        print(num)
        tot = tot + ' ' + str(num)
print(tot)

Just add while its <= and your number for the range.
OUTPUT:
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101

How to insert text in a td with id, using JavaScript

If your <td> is not empty, one popular trick is to insert a non breaking space &nbsp; in it, such that:

 <td id="td1">&nbsp;</td>

Then you will be able to use:

 document.getElementById('td1').firstChild.data = 'New Value';

Otherwise, if you do not fancy adding the meaningless &nbsp you can use the solution that Jonathan Fingland described in the other answer.

Best practice to run Linux service as a different user

On Debian we use the start-stop-daemon utility, which handles pid-files, changing the user, putting the daemon into background and much more.

I'm not familiar with RedHat, but the daemon utility that you are already using (which is defined in /etc/init.d/functions, btw.) is mentioned everywhere as the equivalent to start-stop-daemon, so either it can also change the uid of your program, or the way you do it is already the correct one.

If you look around the net, there are several ready-made wrappers that you can use. Some may even be already packaged in RedHat. Have a look at daemonize, for example.

Regular expression field validation in jQuery

I believe this does it:

http://bassistance.de/jquery-plugins/jquery-plugin-validation/

It's got built-in patterns for stuff like URLs and e-mail addresses, and I think you can have it use your own as well.

jquery (or pure js) simulate enter key pressed for testing

For those who want to do this in pure javascript, look at:

Using standard KeyboardEvent

As Joe comment it, KeyboardEvent is now the standard.

Same example to fire an enter (keyCode 13):

const ke = new KeyboardEvent('keydown', {
    bubbles: true, cancelable: true, keyCode: 13
});
document.body.dispatchEvent(ke);

You can use this page help you to find the right keyboard event.


Outdated answer:

You can do something like (here for Firefox)

var ev = document.createEvent('KeyboardEvent');
// Send key '13' (= enter)
ev.initKeyEvent(
    'keydown', true, true, window, false, false, false, false, 13, 0);
document.body.dispatchEvent(ev);

Putting a simple if-then-else statement on one line

count = 0 if count == N else N+1

- the ternary operator. Although I'd say your solution is more readable than this.

Which is the default location for keystore/truststore of Java applications?

In Java, according to the JSSE Reference Guide, there is no default for the keystore, the default for the truststore is "jssecacerts, if it exists. Otherwise, cacerts".

A few applications use ~/.keystore as a default keystore, but this is not without problems (mainly because you might not want all the application run by the user to use that trust store).

I'd suggest using application-specific values that you bundle with your application instead, it would tend to be more applicable in general.

jQuery jump or scroll to certain position, div or target on the page from button onclick

$("html, body").scrollTop($(element).offset().top); // <-- Also integer can be used

How to get the first and last date of the current year?

If it reaches the 1st of Jan you might it to be still last years date.

select
convert(date, DATEADD(yy, DATEDIFF(yy, 0,  DATEadd(day, -1,getdate())), 0), 103 ) AS StartOfYear,
convert(date, DATEADD(yy, DATEDIFF(yy, 0, DATEDIFF(day, -1,getdate()))+1, -1), 103 )AS EndOfYear

SQL server stored procedure return a table

The Status Value being returned by a Stored Procedure can only be an INT datatype. You cannot return other datatypes in the RETURN statement.

From Lesson 2: Designing Stored Procedures:

Every stored procedure can return an integer value known as the execution status value or return code.

If you still want a table returned from the SP, you'll either have to work the record set returned from a SELECT within the SP or tie into an OUTPUT variable that passes an XML datatype.

HTH,

John

Convert string to buffer Node

This is working for me, you might change your code like this

var responseData=x.toString();

to

var responseData=x.toString("binary");

and finally

response.write(new Buffer(toTransmit, "binary"));

How to detect if a string contains special characters?

SELECT * FROM tableName WHERE columnName LIKE "%#%" OR columnName LIKE "%$%" OR (etc.)

Launch a shell command with in a python script, wait for the termination and return to the script

You can use subprocess.Popen. There's a few ways to do it:

import subprocess
cmd = ['/run/myscript', '--arg', 'value']
p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
for line in p.stdout:
    print line
p.wait()
print p.returncode

Or, if you don't care what the external program actually does:

cmd = ['/run/myscript', '--arg', 'value']
subprocess.Popen(cmd).wait()

Make XmlHttpRequest POST using JSON

If you use JSON properly, you can have nested object without any issue :

var xmlhttp = new XMLHttpRequest();   // new HttpRequest instance 
var theUrl = "/json-handler";
xmlhttp.open("POST", theUrl);
xmlhttp.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
xmlhttp.send(JSON.stringify({ "email": "[email protected]", "response": { "name": "Tester" } }));

Delete empty rows

I believe that your problem is that you're checking for an empty string using double quotes instead of single quotes. Try just changing to:

DELETE FROM table WHERE edit_user=''

How to call another controller Action From a controller in Mvc

I know it's old, but you can:

  • Create a service layer
  • Move method there
  • Call method in both controllers

maxlength ignored for input type="number" in Chrome

Chrome (technically, Blink) will not implement maxlength for <input type="number">.

The HTML5 specification says that maxlength is only applicable to the types text, url, e-mail, search, tel, and password.

Why can't decimal numbers be represented exactly in binary?

For a simple answer: The computer doesn't have infinite memory to store fraction (after representing the decimal number as the form of scientific notation). According to IEEE 754 standard for double-precision floating-point numbers, we only have a limit of 53 bits to store fraction. For more info: http://mathcenter.oxford.emory.edu/site/cs170/ieee754/

Query grants for a table in postgres

I already found it:

SELECT grantee, privilege_type 
FROM information_schema.role_table_grants 
WHERE table_name='mytable'

The static keyword and its various uses in C++

Static Object: We can define class members static using static keyword. When we declare a member of a class as static it means no matter how many objects of the class are created, there is only one copy of the static member.

A static member is shared by all objects of the class. All static data is initialized to zero when the first object is created, if no other initialization is present. We can't put it in the class definition but it can be initialized outside the class as done in the following example by redeclaring the static variable, using the scope resolution operator :: to identify which class it belongs to.

Let us try the following example to understand the concept of static data members:

#include <iostream>

using namespace std;

class Box
{
   public:
      static int objectCount;
      // Constructor definition
      Box(double l=2.0, double b=2.0, double h=2.0)
      {
         cout <<"Constructor called." << endl;
         length = l;
         breadth = b;
         height = h;
         // Increase every time object is created
         objectCount++;
      }
      double Volume()
      {
         return length * breadth * height;
      }
   private:
      double length;     // Length of a box
      double breadth;    // Breadth of a box
      double height;     // Height of a box
};

// Initialize static member of class Box
int Box::objectCount = 0;

int main(void)
{
   Box Box1(3.3, 1.2, 1.5);    // Declare box1
   Box Box2(8.5, 6.0, 2.0);    // Declare box2

   // Print total number of objects.
   cout << "Total objects: " << Box::objectCount << endl;

   return 0;
}

When the above code is compiled and executed, it produces the following result:

Constructor called.
Constructor called.
Total objects: 2

Static Function Members: By declaring a function member as static, you make it independent of any particular object of the class. A static member function can be called even if no objects of the class exist and the static functions are accessed using only the class name and the scope resolution operator ::.

A static member function can only access static data member, other static member functions and any other functions from outside the class.

Static member functions have a class scope and they do not have access to the this pointer of the class. You could use a static member function to determine whether some objects of the class have been created or not.

Let us try the following example to understand the concept of static function members:

#include <iostream>

using namespace std;

class Box
{
   public:
      static int objectCount;
      // Constructor definition
      Box(double l=2.0, double b=2.0, double h=2.0)
      {
         cout <<"Constructor called." << endl;
         length = l;
         breadth = b;
         height = h;
         // Increase every time object is created
         objectCount++;
      }
      double Volume()
      {
         return length * breadth * height;
      }
      static int getCount()
      {
         return objectCount;
      }
   private:
      double length;     // Length of a box
      double breadth;    // Breadth of a box
      double height;     // Height of a box
};

// Initialize static member of class Box
int Box::objectCount = 0;

int main(void)
{

   // Print total number of objects before creating object.
   cout << "Inital Stage Count: " << Box::getCount() << endl;

   Box Box1(3.3, 1.2, 1.5);    // Declare box1
   Box Box2(8.5, 6.0, 2.0);    // Declare box2

   // Print total number of objects after creating object.
   cout << "Final Stage Count: " << Box::getCount() << endl;

   return 0;
}

When the above code is compiled and executed, it produces the following result:

Inital Stage Count: 0
Constructor called.
Constructor called.
Final Stage Count: 2

Check if a property exists in a class

Your method looks like this:

public static bool HasProperty(this object obj, string propertyName)
{
    return obj.GetType().GetProperty(propertyName) != null;
}

This adds an extension onto object - the base class of everything. When you call this extension you're passing it a Type:

var res = typeof(MyClass).HasProperty("Label");

Your method expects an instance of a class, not a Type. Otherwise you're essentially doing

typeof(MyClass) - this gives an instanceof `System.Type`. 

Then

type.GetType() - this gives `System.Type`
Getproperty('xxx') - whatever you provide as xxx is unlikely to be on `System.Type`

As @PeterRitchie correctly points out, at this point your code is looking for property Label on System.Type. That property does not exist.

The solution is either

a) Provide an instance of MyClass to the extension:

var myInstance = new MyClass()
myInstance.HasProperty("Label")

b) Put the extension on System.Type

public static bool HasProperty(this Type obj, string propertyName)
{
    return obj.GetProperty(propertyName) != null;
}

and

typeof(MyClass).HasProperty("Label");

function to remove duplicate characters in a string

Yet another solution, seems to be the most concise so far:

private static String removeDuplicates(String s)
    {   
        String x = new String(s);

        for(int i=0;i<x.length()-1;i++)
            x = x.substring(0,i+1) + (x.substring(i+1)).replace(String.valueOf(x.charAt(i)), "");

        return x;
    }   

window.open with headers

Can I control the HTTP headers sent by window.open (cross browser)?

No

If not, can I somehow window.open a page that then issues my request with custom headers inside its popped-up window?

  • You can request a URL that triggers a server side program which makes the request with arbitrary headers and then returns the response
  • You can run JavaScript (probably saying goodbye to Progressive Enhancement) that uses XHR to make the request with arbitrary headers (assuming the URL fits within the Same Origin Policy) and then process the result in JS.

I need some cunning hacks...

It might help if you described the problem instead of asking if possible solutions would work.

How to get the user input in Java?

You can get user input using BufferedReader.

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String accStr;  

System.out.println("Enter your Account number: ");
accStr = br.readLine();

It will store a String value in accStr so you have to parse it to an int using Integer.parseInt.

int accInt = Integer.parseInt(accStr);

Error during installing HAXM, VT-X not working

Watch this video or try this:

  • check if Hyper-V options in "Windows Features avtivate or deactivate" are deactivated
  • Reboot
  • Install HAXM
  • go to bios and enable vt-x

How can I auto hide alert box after it showing it?

You can't close an alert box with Javascript.

You could, however, use a window instead:

var w = window.open('','','width=100,height=100')
w.document.write('Message')
w.focus()
setTimeout(function() {w.close();}, 5000)

WPF button click in C# code

Button btn = new Button();
btn.Name = "btn1";
btn.Click += btn1_Click;

private void btn1_Click(object sender, RoutedEventArgs e)
{
    // do something
}

How to write subquery inside the OUTER JOIN Statement

You need the "correlation id" (the "AS SS" thingy) on the sub-select to reference the fields in the "ON" condition. The id's assigned inside the sub select are not usable in the join.

SELECT
       cs.CUSID
       ,dp.DEPID
FROM
    CUSTMR cs
        LEFT OUTER JOIN (
            SELECT
                    DEPID
                    ,DEPNAME
                FROM
                    DEPRMNT 
                WHERE
                    dp.DEPADDRESS = 'TOKYO'
        ) ss
            ON (
                ss.DEPID = cs.CUSID
                AND ss.DEPNAME = cs.CUSTNAME
            )
WHERE
    cs.CUSID != '' 

jquery - fastest way to remove all rows from a very large table

Two issues I can see here:

  1. The empty() and remove() methods of jQuery actually do quite a bit of work. See John Resig's JavaScript Function Call Profiling for why.

  2. The other thing is that for large amounts of tabular data you might consider a datagrid library such as the excellent DataTables to load your data on the fly from the server, increasing the number of network calls, but decreasing the size of those calls. I had a very complicated table with 1500 rows that got quite slow, changing to the new AJAX based table made this same data seem rather fast.

Get gateway ip address in android

This seems to work well for me. Tested on Touchwiz 5.1, LineageOS 7.1, and CyanogenMod 11.

ip route list match 0 table all scope global

Gives output similar to this:

default via 192.168.1.1 dev wlan0  table wlan0  proto static

Loop structure inside gnuplot?

Take a look also to the do { ... } command since gnuplot 4.6 as it is very powerful:

do for [t=0:50] {
  outfile = sprintf('animation/bessel%03.0f.png',t)
  set output outfile
  splot u*sin(v),u*cos(v),bessel(u,t/50.0) w pm3d ls 1
}

http://www.gnuplotting.org/gnuplot-4-6-do/

How to use the 'replace' feature for custom AngularJS directives?

When you have replace: true you get the following piece of DOM:

<div ng-controller="Ctrl" class="ng-scope">
    <div class="ng-binding">hello</div>
</div>

whereas, with replace: false you get this:

<div ng-controller="Ctrl" class="ng-scope">
    <my-dir>
        <div class="ng-binding">hello</div>
    </my-dir>
</div>

So the replace property in directives refer to whether the element to which the directive is being applied (<my-dir> in that case) should remain (replace: false) and the directive's template should be appended as its child,

OR

the element to which the directive is being applied should be replaced (replace: true) by the directive's template.

In both cases the element's (to which the directive is being applied) children will be lost. If you wanted to perserve the element's original content/children you would have to translude it. The following directive would do it:

.directive('myDir', function() {
    return {
        restrict: 'E',
        replace: false,
        transclude: true,
        template: '<div>{{title}}<div ng-transclude></div></div>'
    };
});

In that case if in the directive's template you have an element (or elements) with attribute ng-transclude, its content will be replaced by the element's (to which the directive is being applied) original content.

See example of translusion http://plnkr.co/edit/2DJQydBjgwj9vExLn3Ik?p=preview

See this to read more about translusion.

MySQL Results as comma separated list

You can use GROUP_CONCAT to perform that, e.g. something like

SELECT p.id, p.name, GROUP_CONCAT(s.name) AS site_list
FROM sites s
INNER JOIN publications p ON(s.id = p.site_id)
GROUP BY p.id, p.name;

Is there a way to make text unselectable on an HTML page?

If it looks bad you can use CSS to change the appearance of selected sections.

Can I add extension methods to an existing static class?

I stumbled upon this thread while trying to find an answer to the same question the OP had. I didn't find the answer I wanted, but I ended up doing this.

public static class MyConsole
{
    public static void WriteLine(this ConsoleColor Color, string Text)
    {
        Console.ForegroundColor = Color;
        Console.WriteLine(Text);   
    }
}

And I use it like this:

ConsoleColor.Cyan.WriteLine("voilà");

How to extract IP Address in Spring MVC Controller get call?

I use such method to do this

public class HttpReqRespUtils {

    private static final String[] IP_HEADER_CANDIDATES = {
        "X-Forwarded-For",
        "Proxy-Client-IP",
        "WL-Proxy-Client-IP",
        "HTTP_X_FORWARDED_FOR",
        "HTTP_X_FORWARDED",
        "HTTP_X_CLUSTER_CLIENT_IP",
        "HTTP_CLIENT_IP",
        "HTTP_FORWARDED_FOR",
        "HTTP_FORWARDED",
        "HTTP_VIA",
        "REMOTE_ADDR"
    };

    public static String getClientIpAddressIfServletRequestExist() {

        if (RequestContextHolder.getRequestAttributes() == null) {
            return "0.0.0.0";
        }

        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
        for (String header: IP_HEADER_CANDIDATES) {
            String ipList = request.getHeader(header);
            if (ipList != null && ipList.length() != 0 && !"unknown".equalsIgnoreCase(ipList)) {
                String ip = ipList.split(",")[0];
                return ip;
            }
        }

        return request.getRemoteAddr();
    }
}

Send POST request with JSON data using Volley

protected Map<String, String> getParams() {
   Map<String, String> params = new HashMap<String, String>();

   JSONObject JObj = new JSONObject();

   try {
           JObj.put("Id","1");
           JObj.put("Name", "abc");

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

   params.put("params", JObj.toString());
   // Map.Entry<String,String>
   Log.d("Parameter", params.toString());
   return params;
}

How good is Java's UUID.randomUUID?

Does anybody have any experience to share?

There are 2^122 possible values for a type-4 UUID. (The spec says that you lose 2 bits for the type, and a further 4 bits for a version number.)

Assuming that you were to generate 1 million random UUIDs a second, the chances of a duplicate occurring in your lifetime would be vanishingly small. And to detect the duplicate, you'd have to solve the problem of comparing 1 million new UUIDs per second against all of the UUIDs you have previously generated1!

The chances that anyone has experienced (i.e. actually noticed) a duplicate in real life are even smaller than vanishingly small ... because of the practical difficulty of looking for collisions.

Now of course, you will typically be using a pseudo-random number generator, not a source of truly random numbers. But I think we can be confident that if you are using a creditable provider for your cryptographic strength random numbers, then it will be cryptographic strength, and the probability of repeats will be the same as for an ideal (non-biased) random number generator.

However, if you were to use a JVM with a "broken" crypto- random number generator, all bets are off. (And that might include some of the workarounds for "shortage of entropy" problems on some systems. Or the possibility that someone has tinkered with your JRE, either on your system or upstream.)


1 - Assuming that you used "some kind of binary btree" as proposed by an anonymous commenter, each UUID is going to need O(NlogN) bits of RAM memory to represent N distinct UUIDs assuming low density and random distribution of the bits. Now multiply that by 1,000,000 and the number of seconds that you are going to run the experiment for. I don't think that is practical for the length of time needed to test for collisions of a high quality RNG. Not even with (hypothetical) clever representations.

Find the max of two or more columns with pandas

You can get the maximum like this:

>>> import pandas as pd
>>> df = pd.DataFrame({"A": [1,2,3], "B": [-2, 8, 1]})
>>> df
   A  B
0  1 -2
1  2  8
2  3  1
>>> df[["A", "B"]]
   A  B
0  1 -2
1  2  8
2  3  1
>>> df[["A", "B"]].max(axis=1)
0    1
1    8
2    3

and so:

>>> df["C"] = df[["A", "B"]].max(axis=1)
>>> df
   A  B  C
0  1 -2  1
1  2  8  8
2  3  1  3

If you know that "A" and "B" are the only columns, you could even get away with

>>> df["C"] = df.max(axis=1)

And you could use .apply(max, axis=1) too, I guess.

How to debug JavaScript / jQuery event bindings with Firebug or similar tools?

According to this thread, there is no way in Firebug to view what events are attached to listeners on a DOM element.

It looks like the best you can do is either what tj111 suggests, or you could right-click the element in the HTML viewer, and click "Log Events" so you can see which events are firing for a particular DOM element. I suppose one could do that to see what events could be firing off particular functions.

How to Calculate Jump Target Address and Branch Target Address?

(In the diagrams and text below, PC is the address of the branch instruction itself. PC+4 is the end of the branch instruction itself, and the start of the branch delay slot. Except in the absolute jump diagram.)

1. Branch Address Calculation

In MIPS branch instruction has only 16 bits offset to determine next instruction. We need a register added to this 16 bit value to determine next instruction and this register is actually implied by architecture. It is PC register since PC gets updated (PC+4) during the fetch cycle so that it holds the address of the next instruction.

We also limit the branch distance to -2^15 to +2^15 - 1 instruction from the (instruction after the) branch instruction. However, this is not real issue since most branches are local anyway.

So step by step :

  • Sign extend the 16 bit offset value to preserve its value.
  • Multiply resulting value with 4. The reason behind this is that If we are going to branch some address, and PC is already word aligned, then the immediate value has to be word-aligned as well. However, it makes no sense to make the immediate word-aligned because we would be wasting low two bits by forcing them to be 00.
  • Now we have a 32 bit relative offset. Add this value to PC + 4 and that is your branch address.

Branch address calculation


2. Jump Address Calculation

For Jump instruction MIPS has only 26 bits to determine Jump location. Jumps are relative to PC in MIPS. Like branch, immediate jump value needs to be word-aligned; therefore, we need to multiply 26 bit address with four.

Again step by step:

  • Multiply 26 bit value with 4.
  • Since we are jumping relative to PC+4 value, concatenate first four bits of PC+4 value to left of our jump address.
  • Resulting address is the jump value.

In other words, replace the lower 28 bits of the PC + 4 with the lower 26 bits of the fetched instruction shifted left by 2 bits.

enter image description here

Jumps are region-relative to the branch-delay slot, not necessarily the branch itself. In the diagram above, PC has already advanced to the branch delay slot before the jump calculation. (In a classic-RISC 5 stage pipeline, the BD was fetched in the same cycle the jump is decoded, so that PC+4 next instruction address is already available for jumps as well as branches, and calculating relative to the jump's own address would have required extra work to save that address.)

Source: Bilkent University CS 224 Course Slides

How to switch activity without animation in Android?

You can create a style,

 <style name="noAnimTheme" parent="android:Theme">
   <item name="android:windowAnimationStyle">@null</item>
</style>

and set it as theme for your activity in the manifest:

   <activity android:name=".ui.ArticlesActivity" android:theme="@style/noAnimTheme">
    </activity>

You can also define a style to specify custom entry and exit animations. http://developer.android.com/reference/android/R.attr.html#windowEnterAnimation

How to get div height to auto-adjust to background size?

May be this can help, it's not exactly a background, but you get the simple idea

    <style>
div {
    float: left;
    position: relative;
}
div img {
    position: relative;
}

div div {
    position: absolute;
    top:0;
    left:0;
}
</style>

<div>
    <img src="http://www.planwallpaper.com/static/images/recycled_texture_background_by_sandeep_m-d6aeau9_PZ9chud.jpg" />
    <div>Hello</div>
</div>

How to run only one unit test class using Gradle

Run a single test called MyTest:

./gradlew app:testDebug --tests=com.example.MyTest

Convert hex to binary

import binascii
hexa_input = input('Enter hex String to convert to Binary: ')
pad_bits=len(hexa_input)*4
Integer_output=int(hexa_input,16)
Binary_output= bin(Integer_output)[2:]. zfill(pad_bits)
print(Binary_output)
"""zfill(x) i.e. x no of 0 s to be padded left - Integers will overwrite 0 s
starting from right side but remaining 0 s will display till quantity x
[y:] where y is no of output chars which need to destroy starting from left"""

How to add multiple jar files in classpath in linux

For linux users, you should know the following:

  1. $CLASSPATH is specifically what Java uses to look through multiple directories to find all the different classes it needs for your script (unless you explicitly tell it otherwise with the -cp override). Using -cp (--classpath) requires that you keep track of all the directories manually and copy-paste that line every time you run the program (not preferable IMO).

  2. The colon (":") character separates the different directories. There is only one $CLASSPATH and it has all the directories in it. So, when you run "export CLASSPATH=...." you want to include the current value "$CLASSPATH" in order to append to it. For example:

    export CLASSPATH=.
    export CLASSPATH=$CLASSPATH:/usr/share/java/mysql-connector-java-5.1.12.jar
    

    In the first line above, you start CLASSPATH out with just a simple 'dot' which is the path to your current working directory. With that, whenever you run java it will look in the current working directory (the one you're in) for classes. In the second line above, $CLASSPATH grabs the value that you previously entered (.) and appends the path to a mysql dirver. Now, java will look for the driver AND for your classes.

  3. echo $CLASSPATH
    

    is super handy, and what it returns should read like a colon-separated list of all the directories you want java looking in for what it needs to run your script.

  4. Tomcat does not use CLASSPATH. Read what to do about that here: https://tomcat.apache.org/tomcat-8.0-doc/class-loader-howto.html

Sort & uniq in Linux shell

I have worked on some servers where sort don't support '-u' option. there we have to use

sort xyz | uniq

Error with multiple definitions of function

Here is a highly simplified but hopefully relevant view of what happens when you build your code in C++.

C++ splits the load of generating machine executable code in following different phases -

  1. Preprocessing - This is where any macros - #defines etc you might be using get expanded.

  2. Compiling - Each cpp file along with all the #included files in that file directly or indirectly (together called a compilation unit) is converted into machine readable object code.

    This is where C++ also checks that all functions defined (i.e. containing a body in { } e.g. void Foo( int x){ return Boo(x); }) are referring to other functions in a valid manner.

    The way it does that is by insisting that you provide at least a declaration of these other functions (e.g. void Boo(int); ) before you call it so it can check that you are calling it properly among other things. This can be done either directly in the cpp file where it is called or usually in an included header file.

    Note that only the machine code that corresponds to functions defined in this cpp and included files gets built as the object (binary) version of this compilation unit (e.g. Foo) and not the ones that are merely declared (e.g. Boo).

  3. Linking - This is the stage where C++ goes hunting for stuff declared and called in each compilation unit and links it to the places where it is getting called. Now if there was no definition found of this function the linker gives up and errors out. Similarly if it finds multiple definitions of the same function signature (essentially the name and parameter types it takes) it also errors out as it considers it ambiguous and doesn't want to pick one arbitrarily.

The latter is what is happening in your case. By doing a #include of the fun.cpp file, both fun.cpp and mainfile.cpp have a definition of funct() and the linker doesn't know which one to use in your program and is complaining about it.

The fix as Vaughn mentioned above is to not include the cpp file with the definition of funct() in mainfile.cpp and instead move the declaration of funct() in a separate header file and include that in mainline.cpp. This way the compiler will get the declaration of funct() to work with and the linker would get just one definition of funct() from fun.cpp and will use it with confidence.

Why, Fatal error: Class 'PHPUnit_Framework_TestCase' not found in ...?

I am using php 5.6 on window 10 with zend 1.12 version for me adding

require_once 'PHPUnit/Autoload.php';

before

abstract class Zend_Test_PHPUnit_ControllerTestCase extends PHPUnit_Framework_TestCase

worked. We need to add this above statement in ControllerTestCase.php file

How to hide keyboard in swift on pressing return key?

All in One Hide Keyboard and Move View on Keyboard Open: Swift 5

override func viewDidLoad() {
    super.viewDidLoad()
    let tap = UITapGestureRecognizer(target: self, action: #selector(taped))
    view.addGestureRecognizer(tap)
    NotificationCenter.default.addObserver(self, selector: #selector(KeyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(KeyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}


   override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(true)
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
}
 @objc func taped(){

    self.view.endEditing(true)

}

@objc func KeyboardWillShow(sender: NSNotification){

    let keyboardSize : CGSize = ((sender.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue.size)!
    if self.view.frame.origin.y == 0{
        self.view.frame.origin.y -= keyboardSize.height
    }


}

@objc func KeyboardWillHide(sender : NSNotification){

    let keyboardSize : CGSize = ((sender.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size)!
    if self.view.frame.origin.y != 0{
        self.view.frame.origin.y += keyboardSize.height
    }

}

How do I determine whether my calculation of pi is accurate?

The Taylor series is one way to approximate pi. As noted it converges slowly.

The partial sums of the Taylor series can be shown to be within some multiplier of the next term away from the true value of pi.

Other means of approximating pi have similar ways to calculate the max error.

We know this because we can prove it mathematically.

Webdriver Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms

Just Restart the terminal. Terminal is hanged nothing else. Everything will work fine after that

How to find elements by class

Try to check if the div has a class attribute first, like this:

soup = BeautifulSoup(sdata)
mydivs = soup.findAll('div')
for div in mydivs:
    if "class" in div:
        if (div["class"]=="stylelistrow"):
            print div

How to add a Try/Catch to SQL Stored Procedure

See TRY...CATCH (Transact-SQL)

 CREATE PROCEDURE [dbo].[PL_GEN_PROVN_NO1]        
       @GAD_COMP_CODE  VARCHAR(2) =NULL, 
       @@voucher_no numeric =null output 
       AS         
   BEGIN  

     begin try 
         -- your proc code
     end try

     begin catch
          -- what you want to do in catch
     end catch    
  END -- proc end

How to set cellpadding and cellspacing in table with CSS?

The padding inside a table-divider (TD) is a padding property applied to the cell itself.

CSS

td, th {padding:0}

The spacing in-between the table-dividers is a space between cell borders of the TABLE. To make it effective, you have to specify if your table cells borders will 'collapse' or be 'separated'.

CSS

table, td, th {border-collapse:separate}
table {border-spacing:6px}

Try this : https://www.google.ca/search?num=100&newwindow=1&q=css+table+cellspacing+cellpadding+site%3Astackoverflow.com ( 27 100 results )

HttpContext.Current.Request.Url.Host what it returns?

Try this:

string callbackurl = Request.Url.Host != "localhost" 
    ? Request.Url.Host : Request.Url.Authority;

This will work for local as well as production environment. Because the local uses url with port no that is possible using Url.Host.

How to check if a line is blank using regex

The pattern you want is something like this in multiline mode:

^\s*$

Explanation:

  • ^ is the beginning of string anchor.
  • $ is the end of string anchor.
  • \s is the whitespace character class.
  • * is zero-or-more repetition of.

In multiline mode, ^ and $ also match the beginning and end of the line.

References:


A non-regex alternative:

You can also check if a given string line is "blank" (i.e. containing only whitespaces) by trim()-ing it, then checking if the resulting string isEmpty().

In Java, this would be something like this:

if (line.trim().isEmpty()) {
    // line is "blank"
}

The regex solution can also be simplified without anchors (because of how matches is defined in Java) as follows:

if (line.matches("\\s*")) {
    // line is "blank"
}

API references

How to open Visual Studio Code from the command line on OSX?

Note: Only for Windows Users.

As many folks already suggested ways to open code from command prompt using code . command. This will only open Visual Studio Code Stable build. But If you have downloaded Visual Studio Code Insider build/version (Which has all latest build/features but unstable version) then you need to follow below instructions in windows :

  • Go to Control Panel\System and Security\System. Click on Advanced System Settings enter image description here
  • Click on Environment Variables enter image description here
  • Under System Variables tab, Click on Edit for Path Variable enter image description here
  • Add a new path C:\Users\tsabu\AppData\Local\Programs\Microsoft VS Code Insiders\bin (or) C:\Program Files\Microsoft VS Code Insiders\bin based on location at which you have installed vscode insider in your machine. enter image description here

    Open a new command prompt and type code-insiders . to open vscode-insider build/version

Execute ssh with password authentication via windows command prompt

The sshpass utility is meant for exactly this. First, install sshpass by typing this command:

sudo apt-get install sshpass

Then prepend your ssh/scp command with

sshpass -p '<password>' <ssh/scp command>

This program is easiest to install when using Linux.

User should consider using SSH's more secure public key authentication (with the ssh command) instead.

How to set min-height for bootstrap container

Usually, if you are using bootstrap you can do this to set a min-height of 100%.

 <div class="container-fluid min-vh-100"></div>

this will also solve the footer not sticking at the bottom.

you can also do this from CSS with the following class

.stickDamnFooter{min-height: 100vh;}

if this class does not stick your footer just add position: fixed; to that same css class and you will not have this issue in a lifetime. Cheers.

Finding the length of an integer in C

Yes, using sprintf.

int num;
scanf("%d",&num);
char testing[100];
sprintf(testing,"%d",num);
int length = strlen(testing);

Alternatively, you can do this mathematically using the log10 function.

int num;
scanf("%d",&num);
int length;
if (num == 0) {
  length = 1;
} else {    
  length = log10(fabs(num)) + 1;
  if (num < 0) length++;
}

T-SQL: Looping through an array of known values

You can try as below :

declare @list varchar(MAX), @i int
select @i=0, @list ='4,7,12,22,19,'

while( @i < LEN(@list))
begin
    declare @item varchar(MAX)
    SELECT  @item = SUBSTRING(@list,  @i,CHARINDEX(',',@list,@i)-@i)
    select @item

     --do your stuff here with @item 
     exec p_MyInnerProcedure @item 

    set @i = CHARINDEX(',',@list,@i)+1
    if(@i = 0) set @i = LEN(@list) 
end

Limit results in jQuery UI Autocomplete

I did it in following way :

success: function (result) {
response($.map(result.d.slice(0,10), function (item) {
return {
// Mapping to Required columns (Employee Name and Employee No)
label: item.EmployeeName,
value: item.EmployeeNo
}
}
));

How to convert PDF files to images

As for 2018 there is still not a simple answer to the question of how to convert a PDF document to an image in C#; many libraries use Ghostscript licensed under AGPL and in most cases an expensive commercial license is required for production use.

A good alternative might be using the popular 'pdftoppm' utility which has a GPL license; it can be used from C# as command line tool executed with System.Diagnostics.Process. Popular tools are well known in the Linux world, but a windows build is also available.

If you don't want to integrate pdftoppm by yourself, you can use my PdfRenderer popular wrapper (supports both classic .NET Framework and .NET Core) - it is not free, but pricing is very affordable.

How to delete duplicates on a MySQL table?

I find Werner's solution above to be the most convenient because it works regardless of the presence of a primary key, doesn't mess with tables, uses future-proof plain sql, is very understandable.

As I stated in my comment, that solution hasn't been properly explained though. So this is mine, based on it.

1) add a new boolean column

alter table mytable add tokeep boolean;

2) add a constraint on the duplicated columns AND the new column

alter table mytable add constraint preventdupe unique (mycol1, mycol2, tokeep);

3) set the boolean column to true. This will succeed only on one of the duplicated rows because of the new constraint

update ignore mytable set tokeep = true;

4) delete rows that have not been marked as tokeep

delete from mytable where tokeep is null;

5) drop the added column

alter table mytable drop tokeep;

I suggest that you keep the constraint you added, so that new duplicates are prevented in the future.

How to print binary tree diagram?

A Scala solution, adapted from Vasya Novikov's answer and specialized for binary trees:

/** An immutable Binary Tree. */
case class BTree[T](value: T, left: Option[BTree[T]], right: Option[BTree[T]]) {

  /* Adapted from: http://stackoverflow.com/a/8948691/643684 */
  def pretty: String = {
    def work(tree: BTree[T], prefix: String, isTail: Boolean): String = {
      val (line, bar) = if (isTail) ("+-- ", " ") else ("+-- ", "¦")

      val curr = s"${prefix}${line}${tree.value}"

      val rights = tree.right match {
        case None    => s"${prefix}${bar}   +-- Ø"
        case Some(r) => work(r, s"${prefix}${bar}   ", false)
      }

      val lefts = tree.left match {
        case None    => s"${prefix}${bar}   +-- Ø"
        case Some(l) => work(l, s"${prefix}${bar}   ", true)
      }

      s"${curr}\n${rights}\n${lefts}"

    }

    work(this, "", true)
  }
}

C++ IDE for Linux?

I have been using Anjuta for my university projects about 3 years ago. I haven't been using it lately. But it was nice back then, so should be better with the latest releases.

Converting Columns into rows with their respective data in sql server

i solved the query this way

SELECT
    ca.ID, ca.[Name]
FROM [Emp2]
CROSS APPLY (
      Values
         ('ID' , cast(ID as varchar)),
         ('[Name]' , Name)

  ) as CA (ID, Name)

output look like

  ID     Name
------ --------------------------------------------------
ID     1
[Name] Joy
ID     2
[Name] jean
ID     4
[Name] paul

How can I use Bash syntax in Makefile targets?

One way that also works is putting it this way in the first line of the your target:

your-target: $(eval SHELL:=/bin/bash)
    @echo "here shell is $$0"

Rearrange columns using cut

Using sed

Use sed with basic regular expression's nested subexpressions to capture and reorder the column content. This approach is best suited when there are a limited number of cuts to reorder columns, as in this case.

The basic idea is to surround interesting portions of the search pattern with \( and \), which can be played back in the replacement pattern with \# where # represents the sequential position of the subexpression in the search pattern.

For example:

$ echo "foo bar" | sed "s/\(foo\) \(bar\)/\2 \1/"

yields:

bar foo

Text outside a subexpression is scanned but not retained for playback in the replacement string.

Although the question did not discuss fixed width columns, we will discuss here as this is a worthy measure of any solution posed. For simplicity let's assume the file is space delimited although the solution can be extended for other delimiters.

Collapsing Spaces

To illustrate the simplest usage, let's assume that multiple spaces can be collapsed into single spaces, and the the second column values are terminated with EOL (and not space padded).

File:

bash-3.2$ cat f
Column1    Column2
str1       1
str2       2
str3       3
bash-3.2$ od -a f
0000000    C   o   l   u   m   n   1  sp  sp  sp  sp   C   o   l   u   m
0000020    n   2  nl   s   t   r   1  sp  sp  sp  sp  sp  sp  sp   1  nl
0000040    s   t   r   2  sp  sp  sp  sp  sp  sp  sp   2  nl   s   t   r
0000060    3  sp  sp  sp  sp  sp  sp  sp   3  nl 
0000072

Transform:

bash-3.2$ sed "s/\([^ ]*\)[ ]*\([^ ]*\)[ ]*/\2 \1/" f
Column2 Column1
1 str1
2 str2
3 str3
bash-3.2$ sed "s/\([^ ]*\)[ ]*\([^ ]*\)[ ]*/\2 \1/" f | od -a
0000000    C   o   l   u   m   n   2  sp   C   o   l   u   m   n   1  nl
0000020    1  sp   s   t   r   1  nl   2  sp   s   t   r   2  nl   3  sp
0000040    s   t   r   3  nl
0000045

Preserving Column Widths

Let's now extend the method to a file with constant width columns, while allowing columns to be of differing widths.

File:

bash-3.2$ cat f2
Column1    Column2
str1       1
str2       2
str3       3
bash-3.2$ od -a f2
0000000    C   o   l   u   m   n   1  sp  sp  sp  sp   C   o   l   u   m
0000020    n   2  nl   s   t   r   1  sp  sp  sp  sp  sp  sp  sp   1  sp
0000040   sp  sp  sp  sp  sp  nl   s   t   r   2  sp  sp  sp  sp  sp  sp
0000060   sp   2  sp  sp  sp  sp  sp  sp  nl   s   t   r   3  sp  sp  sp
0000100   sp  sp  sp  sp   3  sp  sp  sp  sp  sp  sp  nl
0000114

Transform:

bash-3.2$ sed "s/\([^ ]*\)\([ ]*\) \([^ ]*\)\([ ]*\)/\3\4 \1\2/" f2
Column2 Column1
1       str1      
2       str2      
3       str3      
bash-3.2$ sed "s/\([^ ]*\)\([ ]*\) \([^ ]*\)\([ ]*\)/\3\4 \1\2/" f2 | od -a
0000000    C   o   l   u   m   n   2  sp   C   o   l   u   m   n   1  sp
0000020   sp  sp  nl   1  sp  sp  sp  sp  sp  sp  sp   s   t   r   1  sp
0000040   sp  sp  sp  sp  sp  nl   2  sp  sp  sp  sp  sp  sp  sp   s   t
0000060    r   2  sp  sp  sp  sp  sp  sp  nl   3  sp  sp  sp  sp  sp  sp
0000100   sp   s   t   r   3  sp  sp  sp  sp  sp  sp  nl 
0000114

Lastly although the question's example does not have strings of unequal length, this sed expression support this case.

File:

bash-3.2$ cat f3
Column1    Column2
str1       1      
string2    2      
str3       3      

Transform:

bash-3.2$ sed "s/\([^ ]*\)\([ ]*\) \([^ ]*\)\([ ]*\)/\3\4 \1\2/" f3
Column2 Column1   
1       str1      
2       string2   
3       str3    
bash-3.2$ sed "s/\([^ ]*\)\([ ]*\) \([^ ]*\)\([ ]*\)/\3\4 \1\2/" f3 | od -a
0000000    C   o   l   u   m   n   2  sp   C   o   l   u   m   n   1  sp
0000020   sp  sp  nl   1  sp  sp  sp  sp  sp  sp  sp   s   t   r   1  sp
0000040   sp  sp  sp  sp  sp  nl   2  sp  sp  sp  sp  sp  sp  sp   s   t
0000060    r   i   n   g   2  sp  sp  sp  nl   3  sp  sp  sp  sp  sp  sp
0000100   sp   s   t   r   3  sp  sp  sp  sp  sp  sp  nl 
0000114

Comparison to other methods of column reordering under shell

  • Surprisingly for a file manipulation tool, awk is not well-suited for cutting from a field to end of record. In sed this can be accomplished using regular expressions, e.g. \(xxx.*$\) where xxx is the expression to match the column.

  • Using paste and cut subshells gets tricky when implementing inside shell scripts. Code that works from the commandline fails to parse when brought inside a shell script. At least this was my experience (which drove me to this approach).

jQuery make global variable

Your code looks fine except the possibility that if the variable declaration is inside a dom read handler then it will not be a global variable... it will be a closure variable

jQuery(function(){
    //here it is a closure variable
    var a_href;
    $('sth a').on('click', function(e){
        a_href = $(this).attr('href');

          console.log(a_href);  
         //output is "home"

        e.preventDefault();
    }
})

To make the variable global, one solution is to declare the variable in global scope

var a_href;
jQuery(function(){
    $('sth a').on('click', function(e){
        a_href = $(this).attr('href');

          console.log(a_href);  
         //output is "home"

        e.preventDefault();
    }
})

another is to set the variable as a property of the window object

window.a_href = $(this).attr('href')

Why console printing undefined

You are getting the output as undefined because even though the variable is declared, you have not initialized it with a value, the value of the variable is set only after the a element is clicked till that time the variable will have the value undefined. If you are not declaring the variable it will throw a ReferenceError

Are PHP Variables passed by value or by reference?

Use this for functions when you wish to simply alter the original variable and return it again to the same variable name with its new value assigned.

function add(&$var){ // The &amp; is before the argument $var
   $var++;
}
$a = 1;
$b = 10;
add($a);
echo "a is $a,";
add($b);
echo " a is $a, and b is $b"; // Note: $a and $b are NOT referenced

UML diagram shapes missing on Visio 2013

Microsoft Visio 2013 Standard Edition does not provide UML shapes, you have to upgrade to Microsoft Visio 2013 Professional.

Visio 2013 Professional

How to save RecyclerView's scroll position using RecyclerView.State?

Beginning from version 1.2.0-alpha02 of androidx recyclerView library, it is now automatically managed. Just add it with:

implementation "androidx.recyclerview:recyclerview:1.2.0-alpha02"

And use:

adapter.stateRestorationPolicy = StateRestorationPolicy.PREVENT_WHEN_EMPTY

The StateRestorationPolicy enum has 3 options:

  • ALLOW — the default state, that restores the RecyclerView state immediately, in the next layout pass
  • PREVENT_WHEN_EMPTY — restores the RecyclerView state only when the adapter is not empty (adapter.getItemCount() > 0). If your data is loaded async, the RecyclerView waits until data is loaded and only then the state is restored. If you have default items, like headers or load progress indicators as part of your Adapter, then you should use the PREVENT option, unless the default items are added using MergeAdapter. MergeAdapter waits for all of its adapters to be ready and only then it restores the state.
  • PREVENT — all state restoration is deferred until you set ALLOW or PREVENT_WHEN_EMPTY.

Note that at the time of this answer, recyclerView library is still in alpha03, but alpha phase is not suitable for production purposes.

Array or List in Java. Which is faster?

If you have thousands, consider using a trie. A trie is a tree-like structure that merges the common prefixes of the stored string.

For example, if the strings were

intern
international
internationalize
internet
internets

The trie would store:

intern
 -> \0
 international
 -> \0
 -> ize\0
 net
 ->\0
 ->s\0

The strings requires 57 characters (including the null terminator, '\0') for storage, plus whatever the size of the String object that holds them. (In truth, we should probably round all sizes up to multiples of 16, but...) Call it 57 + 5 = 62 bytes, roughly.

The trie requires 29 (including the null terminator, '\0') for storage, plus sizeof the trie nodes, which are a ref to an array and a list of child trie nodes.

For this example, that probably comes out about the same; for thousands, it probably comes out less as long as you do have common prefixes.

Now, when using the trie in other code, you'll have to convert to String, probably using a StringBuffer as an intermediary. If many of the strings are in use at once as Strings, outside the trie, it's a loss.

But if you're only using a few at the time -- say, to look up things in a dictionary -- the trie can save you a lot of space. Definitely less space than storing them in a HashSet.

You say you're accessing them "serially" -- if that means sequentially an alphabetically, the trie also obviously gives you alphabetical order for free, if you iterate it depth-first.

How to fill a datatable with List<T>

I also had to come up with an alternate solution, as none of the options listed here worked in my case. I was using an IEnumerable and the underlying data was a IEnumerable and the properties couldn't be enumerated. This did the trick:

// remove "this" if not on C# 3.0 / .NET 3.5
public static DataTable ConvertToDataTable<T>(this IEnumerable<T> data)
{
    List<IDataRecord> list = data.Cast<IDataRecord>().ToList();

    PropertyDescriptorCollection props = null;
    DataTable table = new DataTable();
    if (list != null && list.Count > 0)
    {
        props = TypeDescriptor.GetProperties(list[0]);
        for (int i = 0; i < props.Count; i++)
        {
            PropertyDescriptor prop = props[i];
            table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
        }
    }
    if (props != null)
    {
        object[] values = new object[props.Count];
        foreach (T item in data)
        {
            for (int i = 0; i < values.Length; i++)
            {
                values[i] = props[i].GetValue(item) ?? DBNull.Value;
            }
            table.Rows.Add(values);
        }
    }
    return table;
}

Show tables, describe tables equivalent in redshift

In the following post, I documented queries to retrieve TABLE and COLUMN comments from Redshift. https://sqlsylvia.wordpress.com/2017/04/29/redshift-comment-views-documenting-data/

Enjoy!

Table Comments

    SELECT n.nspname AS schema_name
     , pg_get_userbyid(c.relowner) AS table_owner
     , c.relname AS table_name
     , CASE WHEN c.relkind = 'v' THEN 'view' ELSE 'table' END 
       AS table_type
     , d.description AS table_description
     FROM pg_class As c
     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
     LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
     LEFT JOIN pg_description As d 
          ON (d.objoid = c.oid AND d.objsubid = 0)
     WHERE c.relkind IN('r', 'v') AND d.description > ''
     ORDER BY n.nspname, c.relname ;

Column Comments

    SELECT n.nspname AS schema_name
     , pg_get_userbyid(c.relowner) AS table_owner
     , c.relname AS table_name
     , a.attname AS column_name
     , d.description AS column_description
    FROM pg_class AS c
    INNER JOIN pg_attribute As a ON c.oid = a.attrelid
    INNER JOIN pg_namespace n ON n.oid = c.relnamespace
    LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
    LEFT JOIN pg_description As d 
     ON (d.objoid = c.oid AND d.objsubid = a.attnum)
    WHERE c.relkind IN('r', 'v')
     AND a.attname NOT         
     IN ('cmax', 'oid', 'cmin', 'deletexid', 'ctid', 'tableoid','xmax', 'xmin', 'insertxid')
    ORDER BY n.nspname, c.relname, a.attname;

Setting device orientation in Swift iOS

My humble contribution (Xcode 8, Swift 3):

func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
        if let rootViewController = self.topViewControllerWithRootViewController(rootViewController: window?.rootViewController) {
            if (rootViewController.responds(to: Selector(("canRotate")))) {
                // Unlock landscape view orientations for this view controller
                return .allButUpsideDown;
            }
        }
        return .portrait;        
    }

    private func topViewControllerWithRootViewController(rootViewController: UIViewController!) -> UIViewController? {
        if (rootViewController == nil) { return nil }
        if (rootViewController.isKind(of: (UITabBarController).self)) {
            return topViewControllerWithRootViewController(rootViewController: (rootViewController as! UITabBarController).selectedViewController)
        } else if (rootViewController.isKind(of:(UINavigationController).self)) {
            return topViewControllerWithRootViewController(rootViewController: (rootViewController as! UINavigationController).visibleViewController)
        } else if (rootViewController.presentedViewController != nil) {
            return topViewControllerWithRootViewController(rootViewController: rootViewController.presentedViewController)
        }
        return rootViewController
    }

... on the AppDelegate. All the credits for Gandhi Mena: http://www.jairobjunior.com/blog/2016/03/05/how-to-rotate-only-one-view-controller-to-landscape-in-ios-slash-swift/

vagrant primary box defined but commands still run against all boxes

The primary flag seems to only work for vagrant ssh for me.

In the past I have used the following method to hack around the issue.

# stage box intended for configuration closely matching production if ARGV[1] == 'stage'     config.vm.define "stage" do |stage|         box_setup stage, \         "10.9.8.31", "deploy/playbook_full_stack.yml", "deploy/hosts/vagrant_stage.yml"     end end 

Execute another jar in a Java program

If I understand correctly it appears you want to run the jars in a separate process from inside your java GUI application.

To do this you can use:

// Run a java app in a separate system process
Process proc = Runtime.getRuntime().exec("java -jar A.jar");
// Then retreive the process output
InputStream in = proc.getInputStream();
InputStream err = proc.getErrorStream();

Its always good practice to buffer the output of the process.

Can we convert a byte array into an InputStream in Java?

Use ByteArrayInputStream:

InputStream is = new ByteArrayInputStream(decodedBytes);

CSS Classes & SubClasses

kR105 wrote:

you can also have two classes within an element like this

<div class = "item1 item2 item3"></div

I can't see the value of this, since by the principle of cascading styles, the last one takes precedence. For example, if in my earlier example I changed the HTML to read

 <div class="box1 box2"> Hello what is my color? </div>

the box's border and text would be blue, since .box2's style assigns these values.

Also in my earlier post I should have emphasized that adding selectors as I did is not the same as creating a subclass within a class (the first solution in this thread), though the effect is similar.