Programs & Examples On #Low latency

For questions pertaining to the measurement or improvement of latency in a system.

Playing a video in VideoView in Android

VideoView videoView =(VideoView) findViewById(;

Uri uri = Uri.parse(Environment.getExternalStorageDirectory().getAbsolutePath()+"/yourvideo");


Instead of using setVideoPath use setVideoUri. you can get path of your video stored in external storage by using (Environment.getExternalStorageDirectory().getAbsolutePath()+"/yourvideo")and parse it into Uri. If your video is stored in sdcard/MyVideo/video.mp4 replace "/yourvideo" in code by "/MyVideo/video.mp4"

This works fine for me :) `

Determine on iPhone if user has enabled push notifications

Below you'll find a complete example that covers both iOS8 and iOS7 (and lower versions). Please note that prior to iOS8 you can't distinguish between "remote notifications disabled" and "only View in lockscreen enabled".

BOOL remoteNotificationsEnabled = false, noneEnabled,alertsEnabled, badgesEnabled, soundsEnabled;

if ([[UIApplication sharedApplication] respondsToSelector:@selector(registerUserNotificationSettings:)]) {
    // iOS8+
    remoteNotificationsEnabled = [UIApplication sharedApplication].isRegisteredForRemoteNotifications;

    UIUserNotificationSettings *userNotificationSettings = [UIApplication sharedApplication].currentUserNotificationSettings;

    noneEnabled = userNotificationSettings.types == UIUserNotificationTypeNone;
    alertsEnabled = userNotificationSettings.types & UIUserNotificationTypeAlert;
    badgesEnabled = userNotificationSettings.types & UIUserNotificationTypeBadge;
    soundsEnabled = userNotificationSettings.types & UIUserNotificationTypeSound;

} else {
    // iOS7 and below
    UIRemoteNotificationType enabledRemoteNotificationTypes = [UIApplication sharedApplication].enabledRemoteNotificationTypes;

    noneEnabled = enabledRemoteNotificationTypes == UIRemoteNotificationTypeNone;
    alertsEnabled = enabledRemoteNotificationTypes & UIRemoteNotificationTypeAlert;
    badgesEnabled = enabledRemoteNotificationTypes & UIRemoteNotificationTypeBadge;
    soundsEnabled = enabledRemoteNotificationTypes & UIRemoteNotificationTypeSound;

if ([[UIApplication sharedApplication] respondsToSelector:@selector(registerUserNotificationSettings:)]) {
    NSLog(@"Remote notifications enabled: %@", remoteNotificationsEnabled ? @"YES" : @"NO");

NSLog(@"Notification type status:");
NSLog(@"  None: %@", noneEnabled ? @"enabled" : @"disabled");
NSLog(@"  Alerts: %@", alertsEnabled ? @"enabled" : @"disabled");
NSLog(@"  Badges: %@", badgesEnabled ? @"enabled" : @"disabled");
NSLog(@"  Sounds: %@", soundsEnabled ? @"enabled" : @"disabled");

Extract every nth element of a vector

a <- 1:120
b <- a[seq(1, length(a), 6)]

Simple way to create matrix of random numbers

You can drop the range(len()):

weights_h = [[random.random() for e in inputs[0]] for e in range(hiden_neurons)]

But really, you should probably use numpy.

In [9]: numpy.random.random((3, 3))
array([[ 0.37052381,  0.03463207,  0.10669077],
       [ 0.05862909,  0.8515325 ,  0.79809676],
       [ 0.43203632,  0.54633635,  0.09076408]])

How to Run the Procedure?

In SQL Plus:

EXEC gokul_proc(1,'GOKUL', :rc);
print rc

Chrome's remote debugging (USB debugging) not working for Samsung Galaxy S3 running android 4.3

I had success after using ade.exe as explained above, plus using the latest version of Chrome Canary. Apparently your desktop version of Chrome has to be higher than the version running on your Android device.

Remove all of x axis labels in ggplot

You have to set to element_blank() in theme() elements you need to remove

ggplot(data = diamonds, mapping = aes(x = clarity)) + geom_bar(aes(fill = cut))+

UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 13: ordinal not in range(128)

For me there was a problem with the terminal encoding. Adding UTF-8 to .bashrc solved the problem:

export LC_CTYPE=en_US.UTF-8

Don't forget to reload .bashrc afterwards:

source ~/.bashrc

Select second last element with css

In CSS3 you have:



nth-last-child Browser Support:

  • Chrome 2
  • Firefox 3.5
  • Opera 9.5, 10
  • Safari 3.1, 4
  • Internet Explorer 9

Better way to remove specific characters from a Perl string

You've misunderstood how character classes are used:

$varTemp =~ s/[\$#@~!&*()\[\];.,:?^ `\\\/]+//g;

does the same as your regex (assuming you didn't mean to remove ' characters from your strings).

Edit: The + allows several of those "special characters" to match at once, so it should also be faster.

Getting and removing the first character of a string

Use this function from stringi package

> x <- 'hello stackoverflow'
> stri_sub(x,2)
[1] "ello stackoverflow"

How can I schedule a job to run a SQL query daily?

if You want daily backup // following sql script store in C:\Users\admin\Desktop\DBScript\DBBackUpSQL.sql

DECLARE @pathName NVARCHAR(512),
 @databaseName NVARCHAR(512) SET @databaseName = 'Databasename' SET @pathName = 'C:\DBBackup\DBData\DBBackUp' + Convert(varchar(8), GETDATE(), 112) + '_' + Replace((Convert(varchar(8), GETDATE(), 108)),':','-')+ '.bak' BACKUP DATABASE @databaseName TO DISK = @pathName WITH NOFORMAT, 
NAME = N'', 
STATS = 10 

open the Task scheduler

create task-> select Triggers tab Select New .

Button Select Daily Radio button

click Ok Button

then click Action tab Select New.

Button Put "C:\Program Files\Microsoft SQL Server\100\Tools\Binn\SQLCMD.EXE" -S ADMIN-PC -i "C:\Users\admin\Desktop\DBScript\DBBackUpSQL.sql" in the program/script text box(make sure Match your files path and Put the double quoted path in start-> search box and if it find then click it and see the backup is there or not)

-- the above path may be insted 100 write 90 "C:\Program Files\Microsoft SQL Server\90\Tools\Binn\SQLCMD.EXE" -S ADMIN-PC -i "C:\Users\admin\Desktop\DBScript\DBBackUpSQL.sql"

then click ok button

the Script will execute on time which you select on Trigger tab on daily basis

enjoy it.............

Selected tab's color in Bottom Navigation View

It's too late to answer but might be helpful for someone. I was doing a very silly mistake, I was using a selector file named as bottom_color_nav.xml for Select and unselect color change but still it was not reflecting any color change in BottomNavigationView.

Then I realize, I was returning false in onNavigationItemSelected method. It will work fine if you'll return true in this method.

Two-way SSL clarification

Both certificates should exist prior to the connection. They're usually created by Certification Authorities (not necessarily the same). (There are alternative cases where verification can be done differently, but some verification will need to be made.)

The server certificate should be created by a CA that the client trusts (and following the naming conventions defined in RFC 6125).

The client certificate should be created by a CA that the server trusts.

It's up to each party to choose what it trusts.

There are online CA tools that will allow you to apply for a certificate within your browser and get it installed there once the CA has issued it. They need not be on the server that requests client-certificate authentication.

The certificate distribution and trust management is the role of the Public Key Infrastructure (PKI), implemented via the CAs. The SSL/TLS client and servers and then merely users of that PKI.

When the client connects to a server that requests client-certificate authentication, the server sends a list of CAs it's willing to accept as part of the client-certificate request. The client is then able to send its client certificate, if it wishes to and a suitable one is available.

The main advantages of client-certificate authentication are:

  • The private information (the private key) is never sent to the server. The client doesn't let its secret out at all during the authentication.
  • A server that doesn't know a user with that certificate can still authenticate that user, provided it trusts the CA that issued the certificate (and that the certificate is valid). This is very similar to the way passports are used: you may have never met a person showing you a passport, but because you trust the issuing authority, you're able to link the identity to the person.

You may be interested in Advantages of client certificates for client authentication? (on Security.SE).

Capturing "Delete" Keypress with jQuery

    if(e.keyCode == 46) {
        alert('Delete key released');

Source: javascript char codes key codes from

How do I set an absolute include path in PHP?

Not directly answering your question but something to remember:

When using includes with allow_url_include on in your ini beware that, when accessing sessions from included files, if from a script you include one file using an absolute file reference and then include a second file from on your local server using a url file reference that they have different variable scope and the same session will not be seen from both included files. The original session won't be seen from the url included file.


Javascript Confirm popup Yes, No button instead of OK and Cancel

1) You can download and upload below files on your site

<link href="/Style%20Library/css/smoothness/jquery.alerts.css" type="text/css" rel="stylesheet"/> 

2) after that you can directly use below code

$.alerts.okButton = "yes"; $.alerts.cancelButton = "no";

in document.ready function.

Please try it will work.


div background color, to change onhover

you could just contain the div in anchor tag like this:

a div{_x000D_
a div:hover{_x000D_
<a href="">_x000D_
Hover me_x000D_

Border around tr element doesn't show?

Add this to the stylesheet:

table {
  border-collapse: collapse;


The reason why it behaves this way is actually described pretty well in the specification:

There are two distinct models for setting borders on table cells in CSS. One is most suitable for so-called separated borders around individual cells, the other is suitable for borders that are continuous from one end of the table to the other.

... and later, for collapse setting:

In the collapsing border model, it is possible to specify borders that surround all or part of a cell, row, row group, column, and column group.

Right mime type for SVG images with fonts embedded

There's only one registered mediatype for SVG, and that's the one you listed, image/svg+xml. You can of course serve SVG as XML too, though browsers tend to behave differently in some scenarios if you do, for example I've seen cases where SVG used in CSS backgrounds fail to display unless served with the image/svg+xml mediatype.

How do I get the name of a Ruby class?

You want to call .name on the object's class:

How to drop columns using Rails migration

in rails 5 you can use this command in the terminal:

rails generate migration remove_COLUMNNAME_from_TABLENAME COLUMNNAME:DATATYPE

for example to remove the column access_level(string) from table users:

rails generate migration remove_access_level_from_users access_level:string

and then run:

rake db:migrate

How do I make case-insensitive queries on Mongodb?

I just solved this problem a few hours ago.

var thename = 'Andrew'
db.collection.find({ $text: { $search: thename } });
  • Case sensitivity and diacritic sensitivity are set to false by default when doing queries this way.

You can even expand upon this by selecting on the fields you need from Andrew's user object by doing it this way:

db.collection.find({ $text: { $search: thename } }).select('age height weight');


JavaScript replace/regex

In terms of pattern interpretation, there's no difference between the following forms:

  • /pattern/
  • new RegExp("pattern")

If you want to replace a literal string using the replace method, I think you can just pass a string instead of a regexp to replace.

Otherwise, you'd have to escape any regexp special characters in the pattern first - maybe like so:

function reEscape(s) {
    return s.replace(/([.*+?^$|(){}\[\]])/mg, "\\$1");

// ...

var re = new RegExp(reEscape(pattern), "mg");
this.markup = this.markup.replace(re, value);

$(document).ready not Working

One possibility when ready stops working is that you have javascript code somewhere that is throwing an exception in a $(document).ready(...) or $(...) call, which is stopping processing of the rest of the ready blocks. Identify a single page on which this is occurring and examine it for possible errors in other places.

Showing which files have changed between two revisions

And if you are looking for changes only among certain file(s), then:

git diff branch1 branch2 -- myfile1.js myfile2.js

branch1 is optional and your current branch (the branch you are on) will be considered by default if branch1 is not provided. e.g:

git diff master -- controller/index.js

Item frequency count in Python

freqs = {}
for word in words:
    freqs[word] = freqs.get(word, 0) + 1 # fetch and increment OR initialize

I think this results to the same as Triptych's solution, but without importing collections. Also a bit like Selinap's solution, but more readable imho. Almost identical to Thomas Weigel's solution, but without using Exceptions.

This could be slower than using defaultdict() from the collections library however. Since the value is fetched, incremented and then assigned again. Instead of just incremented. However using += might do just the same internally.

Force encode from US-ASCII to UTF-8 (iconv)

Short Answer

  • file only guesses at the file encoding and may be wrong (especially in cases where special characters only appear late in large files).
  • you can use hexdump to look at bytes of non-7-bit-ASCII text and compare against code tables for common encodings (ISO 8859-*, UTF-8) to decide for yourself what the encoding is.
  • iconv will use whatever input/output encoding you specify regardless of what the contents of the file are. If you specify the wrong input encoding, the output will be garbled.
  • even after running iconv, file may not report any change due to the limited way in which file attempts to guess at the encoding. For a specific example, see my long answer.
  • 7-bit ASCII (aka US ASCII) is identical at a byte level to UTF-8 and the 8-bit ASCII extensions (ISO 8859-*). So if your file only has 7-bit characters, then you can call it UTF-8, ISO 8859-* or US ASCII because at a byte level they are all identical. It only makes sense to talk about UTF-8 and other encodings (in this context) once your file has characters outside the 7-bit ASCII range.

Long Answer

I ran into this today and came across your question. Perhaps I can add a little more information to help other people who run into this issue.


First, the term ASCII is overloaded, and that leads to confusion.

7-bit ASCII only includes 128 characters (00-7F or 0-127 in decimal). 7-bit ASCII is also sometimes referred to as US-ASCII.



UTF-8 encoding uses the same encoding as 7-bit ASCII for its first 128 characters. So a text file that only contains characters from that range of the first 128 characters will be identical at a byte level whether encoded with UTF-8 or 7-bit ASCII.

Codepage layout

ISO 8859-* and other ASCII Extensions

The term extended ASCII (or high ASCII) refers to eight-bit or larger character encodings that include the standard seven-bit ASCII characters, plus additional characters.

Extended ASCII

ISO 8859-1 (aka "ISO Latin 1") is a specific 8-bit ASCII extension standard that covers most characters for Western Europe. There are other ISO standards for Eastern European languages and Cyrillic languages. ISO 8859-1 includes characters like Ö, é, ñ and ß for German and Spanish.

"Extension" means that ISO 8859-1 includes the 7-bit ASCII standard and adds characters to it by using the 8th bit. So for the first 128 characters, it is equivalent at a byte level to ASCII and UTF-8 encoded files. However, when you start dealing with characters beyond the first 128, your are no longer UTF-8 equivalent at the byte level, and you must do a conversion if you want your "extended ASCII" file to be UTF-8 encoded.

ISO 8859 and proprietary adaptations

Detecting encoding with file

One lesson I learned today is that we can't trust file to always give correct interpretation of a file's character encoding.

file (command)

The command tells only what the file looks like, not what it is (in the case where file looks at the content). It is easy to fool the program by putting a magic number into a file the content of which does not match it. Thus the command is not usable as a security tool other than in specific situations.

file looks for magic numbers in the file that hint at the type, but these can be wrong, no guarantee of correctness. file also tries to guess the character encoding by looking at the bytes in the file. Basically file has a series of tests that helps it guess at the file type and encoding.

My file is a large CSV file. file reports this file as US ASCII encoded, which is WRONG.

$ ls -lh
total 850832
-rw-r--r--  1 mattp  staff   415M Mar 14 16:38 source-file
$ file -b --mime-type source-file
$ file -b --mime-encoding source-file

My file has umlauts in it (ie Ö). The first non-7-bit-ascii doesn't show up until over 100k lines into the file. I suspect this is why file doesn't realize the file encoding isn't US-ASCII.

$ pcregrep -no '[^\x00-\x7F]' source-file | head -n1

I'm on a Mac, so using PCRE's grep. With GNU grep you could use the -P option. Alternatively on a Mac, one could install coreutils (via Homebrew or other) in order to get GNU grep.

I haven't dug into the source-code of file, and the man page doesn't discuss the text encoding detection in detail, but I am guessing file doesn't look at the whole file before guessing encoding.

Whatever my file's encoding is, these non-7-bit-ASCII characters break stuff. My German CSV file is ;-separated and extracting a single column doesn't work.

$ cut -d";" -f1 source-file > tmp
cut: stdin: Illegal byte sequence
$ wc -l *
 3081673 source-file
  102320 tmp
 3183993 total

Note the cut error and that my "tmp" file has only 102320 lines with the first special character on line 102321.

Let's take a look at how these non-ASCII characters are encoded. I dump the first non-7-bit-ascii into hexdump, do a little formatting, remove the newlines (0a) and take just the first few.

$ pcregrep -o '[^\x00-\x7F]' source-file | head -n1 | hexdump -v -e '1/1 "%02x\n"'

Another way. I know the first non-7-bit-ASCII char is at position 85 on line 102321. I grab that line and tell hexdump to take the two bytes starting at position 85. You can see the special (non-7-bit-ASCII) character represented by a ".", and the next byte is "M"... so this is a single-byte character encoding.

$ tail -n +102321 source-file | head -n1 | hexdump -C -s85 -n2
00000055  d6 4d                                             |.M|

In both cases, we see the special character is represented by d6. Since this character is an Ö which is a German letter, I am guessing that ISO 8859-1 should include this. Sure enough, you can see "d6" is a match (ISO/IEC 8859-1).

Important question... how do I know this character is an Ö without being sure of the file encoding? The answer is context. I opened the file, read the text and then determined what character it is supposed to be. If I open it in Vim it displays as an Ö because Vim does a better job of guessing the character encoding (in this case) than file does.

So, my file seems to be ISO 8859-1. In theory I should check the rest of the non-7-bit-ASCII characters to make sure ISO 8859-1 is a good fit... There is nothing that forces a program to only use a single encoding when writing a file to disk (other than good manners).

I'll skip the check and move on to conversion step.

$ iconv -f iso-8859-1 -t utf8 source-file > output-file
$ file -b --mime-encoding output-file

Hmm. file still tells me this file is US ASCII even after conversion. Let's check with hexdump again.

$ tail -n +102321 output-file | head -n1 | hexdump -C -s85 -n2
00000055  c3 96                                             |..|

Definitely a change. Note that we have two bytes of non-7-bit-ASCII (represented by the "." on the right) and the hex code for the two bytes is now c3 96. If we take a look, seems we have UTF-8 now (c3 96 is the encoding of Ö in UTF-8) UTF-8 encoding table and Unicode characters

But file still reports our file as us-ascii? Well, I think this goes back to the point about file not looking at the whole file and the fact that the first non-7-bit-ASCII characters don't occur until late in the file.

I'll use sed to stick a Ö at the beginning of the file and see what happens.

$ sed '1s/^/Ö\'$'\n/' source-file > test-file
$ head -n1 test-file
$ head -n1 test-file | hexdump -C
00000000  c3 96 0a                                          |...|

Cool, we have an umlaut. Note the encoding though is c3 96 (UTF-8). Hmm.

Checking our other umlauts in the same file again:

$ tail -n +102322 test-file | head -n1 | hexdump -C -s85 -n2
00000055  d6 4d                                             |.M|

ISO 8859-1. Oops! It just goes to show how easy it is to get the encodings screwed up. To be clear, I've managed to create a mix of UTF-8 and ISO 8859-1 encodings in the same file.

Let's try converting our new test file with the umlaut (Ö) at the front and see what happens.

$ iconv -f iso-8859-1 -t utf8 test-file > test-file-converted
$ head -n1 test-file-converted | hexdump -C
00000000  c3 83 c2 96 0a                                    |.....|
$ tail -n +102322 test-file-converted | head -n1 | hexdump -C -s85 -n2
00000055  c3 96                                             |..|

Oops. The first umlaut that was UTF-8 was interpreted as ISO 8859-1 since that is what we told iconv. The second umlaut is correctly converted from d6 (ISO 8859-1) to c3 96 (UTF-8).

I'll try again, but this time I will use Vim to do the Ö insertion instead of sed. Vim seemed to detect the encoding better (as "latin1" aka ISO 8859-1) so perhaps it will insert the new Ö with a consistent encoding.

$ vim source-file
$ head -n1 test-file-2
$ head -n1 test-file-2 | hexdump -C
00000000  d6 0d 0a                                          |...|
$ tail -n +102322 test-file-2 | head -n1 | hexdump -C -s85 -n2
00000055  d6 4d                                             |.M|

It looks good. It looks like ISO 8859-1 for new and old umlauts.

Now the test.

$ file -b --mime-encoding test-file-2
$ iconv -f iso-8859-1 -t utf8 test-file-2 > test-file-2-converted
$ file -b --mime-encoding test-file-2-converted

Boom! Moral of the story. Don't trust file to always guess your encoding right. It is easy to mix encodings within the same file. When in doubt, look at the hex.

A hack (also prone to failure) that would address this specific limitation of file when dealing with large files would be to shorten the file to make sure that special (non-ascii) characters appear early in the file so file is more likely to find them.

$ first_special=$(pcregrep -o1 -n '()[^\x00-\x7F]' source-file | head -n1 | cut -d":" -f1)
$ tail -n +$first_special source-file > /tmp/source-file-shorter
$ file -b --mime-encoding /tmp/source-file-shorter

You could then use (presumably correct) detected encoding to feed as input to iconv to ensure you are converting correctly.


Christos Zoulas updated file to make the amount of bytes looked at configurable. One day turn-around on the feature request, awesome! Allow altering how many bytes to read from analyzed files from the command line

The feature was released in file version 5.26.

Looking at more of a large file before making a guess about encoding takes time. However, it is nice to have the option for specific use-cases where a better guess may outweigh additional time and I/O.

Use the following option:

-P, --parameter name=value

    Set various parameter limits.

    Name    Default     Explanation
    bytes   1048576     max number of bytes to read from file

Something like...

bytes_to_scan=$(wc -c < $file_to_check)
file -b --mime-encoding -P bytes=$bytes_to_scan $file_to_check

... it should do the trick if you want to force file to look at the whole file before making a guess. Of course, this only works if you have file 5.26 or newer.

Forcing file to display UTF-8 instead of US-ASCII

Some of the other answers seem to focus on trying to make file display UTF-8 even if the file only contains plain 7-bit ascii. If you think this through you should probably never want to do this.

  1. If a file contains only 7-bit ascii but the file command is saying the file is UTF-8, that implies that the file contains some characters with UTF-8 specific encoding. If that isn't really true, it could cause confusion or problems down the line. If file displayed UTF-8 when the file only contained 7-bit ascii characters, this would be a bug in the file program.
  2. Any software that requires UTF-8 formatted input files should not have any problem consuming plain 7-bit ascii since this is the same on a byte level as UTF-8. If there is software that is using the file command output before accepting a file as input and it won't process the file unless it "sees" UTF-8...well that is pretty bad design. I would argue this is a bug in that program.

If you absolutely must take a plain 7-bit ascii file and convert it to UTF-8, simply insert a single non-7-bit-ascii character into the file with UTF-8 encoding for that character and you are done. But I can't imagine a use-case where you would need to do this. The easiest UTF-8 character to use for this is the Byte Order Mark (BOM) which is a special non-printing character that hints that the file is non-ascii. This is probably the best choice because it should not visually impact the file contents as it will generally be ignored.

Microsoft compilers and interpreters, and many pieces of software on Microsoft Windows such as Notepad treat the BOM as a required magic number rather than use heuristics. These tools add a BOM when saving text as UTF-8, and cannot interpret UTF-8 unless the BOM is present or the file contains only ASCII.

This is key:

or the file contains only ASCII

So some tools on windows have trouble reading UTF-8 files unless the BOM character is present. However this does not affect plain 7-bit ascii only files. I.e. this is not a reason for forcing plain 7-bit ascii files to be UTF-8 by adding a BOM character.

Here is more discussion about potential pitfalls of using the BOM when not needed (it IS needed for actual UTF-8 files that are consumed by some Microsoft apps).

Nevertheless if you still want to do it, I would be interested in hearing your use case. Here is how. In UTF-8 the BOM is represented by hex sequence 0xEF,0xBB,0xBF and so we can easily add this character to the front of our plain 7-bit ascii file. By adding a non-7-bit ascii character to the file, the file is no longer only 7-bit ascii. Note that we have not modified or converted the original 7-bit-ascii content at all. We have added a single non-7-bit-ascii character to the beginning of the file and so the file is no longer entirely composed of 7-bit-ascii characters.

$ printf '\xEF\xBB\xBF' > bom.txt # put a UTF-8 BOM char in new file
$ file bom.txt
bom.txt: UTF-8 Unicode text, with no line terminators
$ file plain-ascii.txt  # our pure 7-bit ascii file
plain-ascii.txt: ASCII text
$ cat bom.txt plain-ascii.txt > plain-ascii-with-utf8-bom.txt # put them together into one new file with the BOM first
$ file plain-ascii-with-utf8-bom.txt
plain-ascii-with-utf8-bom.txt: UTF-8 Unicode (with BOM) text


In my case, I was installing a project with MinimumSDK bigger than the Android version of my real device. I used another device and it solved MinSDK -> 24 My Phone -> 21

powershell is missing the terminator: "

In my specific case of the same issue, it was caused by not having the Powershell script saved with an encoding of Windows-1252 or UFT-8 WITH BOM.

Redirect using AngularJS

Assuming you're not using html5 routing, try $location.path("route"). This will redirect your browser to #/route which might be what you want.

How to remove elements/nodes from angular.js array

I liked the solution provided by @madhead

However the problem I had is that it wouldn't work for a sorted list so instead of passing the index to the delete function I passed the item and then got the index via indexof


var index = $scope.items.indexOf(item);
$scope.items.splice(index, 1);

An updated version of madheads example is below: link to example


<!DOCTYPE html>
<html data-ng-app="demo">
    <script data-require="[email protected]" data-semver="1.1.5" src=""></script>
    <link rel="stylesheet" href="style.css" />
    <script src="script.js"></script>
    <div data-ng-controller="DemoController">
        <li data-ng-repeat="item in items|orderBy:'toString()'">
          <button data-ng-click="removeItem(item)">Remove</button>
      <input data-ng-model="newItem"><button data-ng-click="addItem(newItem)">Add</button>


"use strict";

var demo = angular.module("demo", []);

function DemoController($scope){
  $scope.items = [

  $scope.addItem = function(item){
    $scope.newItem = null;

  $scope.removeItem = function(item){
    var index = $scope.items.indexOf(item);
    $scope.items.splice(index, 1);

jQuery position DIV fixed at top on scroll

instead of doing it like that, why not just make the flyout position:fixed, top:0; left:0; once your window has scrolled pass a certain height:


      if ($(this).scrollTop() > 135) {
      } else {


.fixed {position:fixed; top:0; left:0;}


Deleting a local branch with Git

Ran into this today and switching to another branch didn't help. It turned out that somehow my worktree information had gotten corrupted and there was a worktree with the same folder path as my working directory with a HEAD pointing at the branch (git worktree list). I deleted the .git/worktree/ folder that was referencing it and git branch -d worked.

Select N random elements from a List<T> in C#

public static IEnumerable<T> GetRandom<T>(this IList<T> list, int count, Random random)
        // Probably you should throw exception if count > list.Count
        count = Math.Min(list.Count, count);

        var selectedIndices = new SortedSet<int>();

        // Random upper bound
        int randomMax = list.Count - 1;

        while (selectedIndices.Count < count)
            int randomIndex = random.Next(0, randomMax);

            // skip over already selected indeces
            foreach (var selectedIndex in selectedIndices)
                if (selectedIndex <= randomIndex)

            yield return list[randomIndex];


Memory: ~count
Complexity: O(count2)

String to char array Java

A string to char array is as simple as

String str = "someString"; 
char[] charArray = str.toCharArray();

Can you explain a little more on what you are trying to do?

* Update *

if I am understanding your new comment, you can use a byte array and example is provided.

byte[] bytes = ByteBuffer.allocate(4).putInt(1695609641).array();

for (byte b : bytes) {
   System.out.format("0x%x ", b);

With the following output

0x65 0x10 0xf3 0x29

Is there anyway to exclude artifacts inherited from a parent POM?

Have you tried explicitly declaring the version of mail.jar you want? Maven's dependency resolution should use this for dependency resolution over all other versions.


Execute JavaScript code stored as a string

If you want to execute a specific command (that is string) after a specific time - cmd=your code - InterVal=delay to run

 function ExecStr(cmd, InterVal) {
    try {
        setTimeout(function () {
            var F = new Function(cmd);
            return (F());
        }, InterVal);
    } catch (e) { }

Regular expression to search multiple strings (Textpad)

If I understand what you are asking, it is a regular expression like this:


This matches the three sets of digit strings at beginning of line only.

Set default value of javascript object attributes

my code is:

    s = {
        top: || 100,    // default value or
        left: s.left || 300,  // default value or s.left

How do I delete multiple rows in Entity Framework (without foreach)

Still seems crazy to have to pull anything back from the server just to delete it, but at least getting back just the IDs is a lot leaner than pulling down the full entities:

var ids = from w in context.Widgets where w.WidgetId == widgetId select w.Id;
context.Widgets.RemoveRange(from id in ids.AsEnumerable() select new Widget { Id = id });

Oracle row count of table by count(*) vs NUM_ROWS from DBA_TABLES

According to the documentation NUM_ROWS is the "Number of rows in the table", so I can see how this might be confusing. There, however, is a major difference between these two methods.

This query selects the number of rows in MY_TABLE from a system view. This is data that Oracle has previously collected and stored.

select num_rows from all_tables where table_name = 'MY_TABLE'

This query counts the current number of rows in MY_TABLE

select count(*) from my_table

By definition they are difference pieces of data. There are two additional pieces of information you need about NUM_ROWS.

  1. In the documentation there's an asterisk by the column name, which leads to this note:

    Columns marked with an asterisk (*) are populated only if you collect statistics on the table with the ANALYZE statement or the DBMS_STATS package.

    This means that unless you have gathered statistics on the table then this column will not have any data.

  2. Statistics gathered in 11g+ with the default estimate_percent, or with a 100% estimate, will return an accurate number for that point in time. But statistics gathered before 11g, or with a custom estimate_percent less than 100%, uses dynamic sampling and may be incorrect. If you gather 99.999% a single row may be missed, which in turn means that the answer you get is incorrect.

If your table is never updated then it is certainly possible to use ALL_TABLES.NUM_ROWS to find out the number of rows in a table. However, and it's a big however, if any process inserts or deletes rows from your table it will be at best a good approximation and depending on whether your database gathers statistics automatically could be horribly wrong.

Generally speaking, it is always better to actually count the number of rows in the table rather then relying on the system tables.

How do you select the entire excel sheet with Range using VBA?

you have a few options here:

  1. Using the UsedRange property
  2. find the last row and column used
  3. use a mimic of shift down and shift right

I personally use the Used Range and find last row and column method most of the time.

Here's how you would do it using the UsedRange property:


This statement will select all used ranges in the worksheet, note that sometimes this doesn't work very well when you delete columns and rows.

The alternative is to find the very last cell used in the worksheet

Dim rngTemp As Range
Set rngTemp = Cells.Find("*", SearchOrder:=xlByRows, SearchDirection:=xlPrevious)
If Not rngTemp Is Nothing Then
    Range(Cells(1, 1), rngTemp).Select
End If

What this code is doing:

  1. Find the last cell containing any value
  2. select cell(1,1) all the way to the last cell

Java Currency Number format

you should do something like this:

public static void main(String[] args) {
    double d1 = 100d;
    double d2 = 100.1d;

private static void print(double d) {
    String s = null;
    if (Math.round(d) != d) {
        s = String.format("%.2f", d);
    } else {
        s = String.format("%.0f", d);

which prints:



Deserialize JSON with C#


// Convert an object to JSON string format
string jsonData = JsonConvert.SerializeObject(obj);



To deserialize a dynamic object

  string json = @"{
      'Name': 'name',
      'Description': 'des'

var res = JsonConvert.DeserializeObject< dynamic>(json);


How to validate phone numbers using regex

My gut feeling is reinforced by the amount of replies to this topic - that there is a virtually infinite number of solutions to this problem, none of which are going to be elegant.

Honestly, I would recommend you don't try to validate phone numbers. Even if you could write a big, hairy validator that would allow all the different legitimate formats, it would end up allowing pretty much anything even remotely resembling a phone number in the first place.

In my opinion, the most elegant solution is to validate a minimum length, nothing more.

How to add button in ActionBar(Android)?

An activity populates the ActionBar in its onCreateOptionsMenu() method.

Instead of using setcustomview(), just override onCreateOptionsMenu like this:

public boolean onCreateOptionsMenu(Menu menu) {
  MenuInflater inflater = getMenuInflater();
  inflater.inflate(, menu);
  return true;

If an actions in the ActionBar is selected, the onOptionsItemSelected() method is called. It receives the selected action as parameter. Based on this information you code can decide what to do for example:

public boolean onOptionsItemSelected(MenuItem item) {
  switch (item.getItemId()) {
      Toast.makeText(this, "Menu Item 1 selected", Toast.LENGTH_SHORT).show();
      Toast.makeText(this, "Menu item 2 selected", Toast.LENGTH_SHORT).show();
  return true;

Plotting a 3d cube, a sphere and a vector in Matplotlib

It is a little complicated, but you can draw all the objects by the following code:

from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
import numpy as np
from itertools import product, combinations

fig = plt.figure()
ax = fig.gca(projection='3d')

# draw cube
r = [-1, 1]
for s, e in combinations(np.array(list(product(r, r, r))), 2):
    if np.sum(np.abs(s-e)) == r[1]-r[0]:
        ax.plot3D(*zip(s, e), color="b")

# draw sphere
u, v = np.mgrid[0:2*np.pi:20j, 0:np.pi:10j]
x = np.cos(u)*np.sin(v)
y = np.sin(u)*np.sin(v)
z = np.cos(v)
ax.plot_wireframe(x, y, z, color="r")

# draw a point
ax.scatter([0], [0], [0], color="g", s=100)

# draw a vector
from matplotlib.patches import FancyArrowPatch
from mpl_toolkits.mplot3d import proj3d

class Arrow3D(FancyArrowPatch):

    def __init__(self, xs, ys, zs, *args, **kwargs):
        FancyArrowPatch.__init__(self, (0, 0), (0, 0), *args, **kwargs)
        self._verts3d = xs, ys, zs

    def draw(self, renderer):
        xs3d, ys3d, zs3d = self._verts3d
        xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, renderer.M)
        self.set_positions((xs[0], ys[0]), (xs[1], ys[1]))
        FancyArrowPatch.draw(self, renderer)

a = Arrow3D([0, 1], [0, 1], [0, 1], mutation_scale=20,
            lw=1, arrowstyle="-|>", color="k")


How does one check if a table exists in an Android SQLite database?

..... Toast t = Toast.makeText(context, "try... " , Toast.LENGTH_SHORT);;

    Cursor callInitCheck = db.rawQuery("select count(*) from call", null);

    Toast t2a = Toast.makeText(context, "count rows " + callInitCheck.getCount() , Toast.LENGTH_SHORT);;

    if( Integer.parseInt( callInitCheck.getString(0)) == 0) // if no rows then do
        // if empty then insert into call


Counting null and non-null values in a single query

    (select count(*) AS 'NULLs', 0 as 'NOTNULLs' FROM us WHERE a is null
    UNION select 0 as 'NULLs', count(*) AS 'NOTNULLs' FROM us WHERE a is not null) AS x

It's fugly, but it will return a single record with 2 cols indicating the count of nulls vs non nulls.

My prerelease app has been "processing" for over a week in iTunes Connect, what gives?

I ran into this issue yesterday. I submitted multiple builds with a variety of different settings. What finally worked for me was submitting through Application Loader with no bitcode.

I hope this helps someone avoid the headache I went through. Its been 24 hours and the apps submitted through Xcode are all still "processing", the one submitted through Application Loader was available within an hour or so.

Regex that matches integers in between whitespace or start/end of string only

Similar to manojlds but includes the optional negative/positive numbers:

var regex = /^[-+]?\d+$/;


If you don't want to allow zeros in the front (023 becomes invalid), you could write it this way:

var regex = /^[-+]?[1-9]\d*$/;


As @DmitriyLezhnev pointed out, if you want to allow the number 0 to be valid by itself but still invalid when in front of other numbers (example: 0 is valid, but 023 is invalid). Then you could use

var regex = /^([+-]?[1-9]\d*|0)$/

What is __pycache__?

from the official python tutorial Modules

To speed up loading modules, Python caches the compiled version of each module in the __pycache__ directory under the name module.version.pyc, where the version encodes the format of the compiled file; it generally contains the Python version number. For example, in CPython release 3.6 the compiled version of would be cached as __pycache__/spam.cpython-36.pyc.

from Python doc Programming FAQs

When a module is imported for the first time (or when the source file has changed since the current compiled file was created) a .pyc file containing the compiled code should be created in a __pycache__ subdirectory of the directory containing the .py file. The .pyc file will have a filename that starts with the same name as the .py file, and ends with .pyc, with a middle component that depends on the particular python binary that created it.

Add a border outside of a UIView (instead of inside)

Ok, there already is an accepted answer but I think there is a better way to do it, you just have to had a new layer a bit larger than your view and do not mask it to the bounds of the view's layer (which actually is the default behaviour). Here is the sample code :

CALayer * externalBorder = [CALayer layer];
externalBorder.frame = CGRectMake(-1, -1, myView.frame.size.width+2, myView.frame.size.height+2);
externalBorder.borderColor = [UIColor blackColor].CGColor;
externalBorder.borderWidth = 1.0;

[myView.layer addSublayer:externalBorder];
myView.layer.masksToBounds = NO;

Of course this is if you want your border to be 1 unity large, if you want more you adapt the borderWidth and the frame of the layer accordingly. This is better than using a second view a bit larger as a CALayer is lighter than a UIView and you don't have do modify the frame of myView, which is good for instance if myView is aUIImageView

N.B : For me the result was not perfect on simulator (the layer was not exactly at the right position so the layer was thicker on one side sometimes) but was exactly what is asked for on real device.


Actually the problem I talk about in the N.B was just because I had reduced the screen of the simulator, on normal size there is absolutely no issue

Hope it helps

python exception message capturing

Use str(ex) to print execption

   #your code
except ex:

Check time difference in Javascript

You can set your custom difference by inserting values in end and updatedAt

getDifference(theDate: string): string {
let end = moment(moment(moment()).valueOf());
let updatedAt = moment(new Date(theDate).valueOf());
let diff = end.diff(updatedAt, "hour", false);
if (diff > 8760) {
  diff = end.diff(updatedAt, "years", false);
  return diff > 1 ? diff + " years ago" : diff + " year ago";
} else if (diff > 730) {
  diff = end.diff(updatedAt, "months", false);
  return diff > 1 ? diff + " months ago" : diff + " month ago";
} else if (diff > 24) {
  diff = end.diff(updatedAt, "days", false);
  return diff > 1 ? diff + " days ago" : diff + " day ago";
} else if (diff <= 0) {
  diff = end.diff(updatedAt, "minutes", false);
  return diff > 1 ? diff + " minutes ago" : diff + " minute ago";
} else return diff > 1 ? diff + " hours ago" : diff + " hour ago";


how to initialize a char array?

what is the best way to do this in C++?

Because you asked it this way:

std::string msg(65546, 0); // all characters will be set to 0


std::vector<char> msg(65546); // all characters will be initialized to 0

If you are working with C functions which accept char* or const char*, then you can do:


You can also use the c_str() method on std::string if it accepts const char* or data().

The benefit of this approach is that you can do everything you want to do with a dynamically allocating char buffer but more safely, flexibly, and sometimes even more efficiently (avoiding the need to recompute string length linearly, e.g.). Best of all, you don't have to free the memory allocated manually, as the destructor will do this for you.

Is it possible to send an array with the Postman Chrome extension?

This also works for lists within the object:


the equivalent JSON would be:

    "Id": 37,
    "IdParent": 26,
    "Name": "Poplet",
    "Values": [
            "Id": 1349,
            "Name": "SomeName"
            "Id": 1350,
            "Name": "AnotherName"

How can I create an Asynchronous function in Javascript?

here you have simple solution (other write about it)

And here you have above ready solution:

function async(your_function, callback) {
    setTimeout(function() {
        if (callback) {callback();}
    }, 0);

TEST 1 (may output '1 x 2 3' or '1 2 x 3' or '1 2 3 x'):

async(function() {console.log('x')}, null);

TEST 2 (will always output 'x 1'):

async(function() {console.log('x');}, function() {console.log(1);});

This function is executed with timeout 0 - it will simulate asynchronous task

Linux Process States

Yes, tasks waiting for IO are blocked, and other tasks get executed. Selecting the next task is done by the Linux scheduler.

What does EntityManager.flush do and why do I need to use it?

A call to EntityManager.flush(); will force the data to be persist in the database immediately as EntityManager.persist() will not (depending on how the EntityManager is configured : FlushModeType (AUTO or COMMIT) by default it's set to AUTO and a flush will be done automatically by if it's set to COMMIT the persitence of the data to the underlying database will be delayed when the transaction is commited).

How to use regex in String.contains() method in Java

matcher.find() does what you needed. Example:


Importing class/java files in Eclipse

First, you don't need the .class files if they are compiled from your .java classes.

To import your files, you need to create an empty Java project. They you either import them one by one (New -> File -> Advanced -> Link file) or directly copy them into their corresponding folder/package and refresh the project.

AttributeError: 'datetime' module has no attribute 'strptime'

I got the same problem and it is not the solution that you told. So I changed the "from datetime import datetime" to "import datetime". After that with the help of "datetime.datetime" I can get the whole modules correctly. I guess this is the correct answer to that question.

Excel VBA Automation Error: The object invoked has disconnected from its clients

I have just met this problem today: I migrated my Excel project from Office 2007 to 2010. At a certain point, when my macro tried to Insert a new line (e.g. Range("5:5").Insert ), the same error message came. It happens only when previously another sheet has been edited (my macro switches to another sheet).

Thanks to Google, and your discussion, I found the following solution (based on the answer given by "red" at answered Jul 30 '13 at 0:27): after switching to the sheet a Cell has to be edited before inserting a new row. I have added the following code:

'=== Excel bugfix workaround - 2014.08.17
vCellValue = Range("B1").Value
Range("B1").Value = vCellValue

"B1" can be replaced by any cell on the sheet.

IE9 JavaScript error: SCRIPT5007: Unable to get value of the property 'ui': object is null or undefined

I was also facing the same issue.

I was using the code below in .aspx page without writing authentication configuration in web.config file. After writing the settings in Web.config, I am able to run my code.

<% If Request.IsAuthenticated Then%>
<%end if%> 

Difference between JSON.stringify and JSON.parse

JavaScript Object <-> JSON String

JSON.stringify() <-> JSON.parse()

JSON.stringify(obj) - Takes any serializable object and returns the JSON representation as a string.

JSON.stringify() -> Object To String.

JSON.parse(string) - Takes a well formed JSON string and returns the corresponding JavaScript object.

JSON.parse() -> String To Object.

Explanation: JSON.stringify(obj [, replacer [, space]]);

Replacer/Space - optional or takes integer value or you can call interger type return function.

function replacer(key, value) {
    if (typeof value === 'number' && !isFinite(value)) {
        return String(value);
    return value;
  • Replacer Just Use for replace non finite no with null.
  • Space use for indenting Json String by space

Gradle: How to Display Test Results in the Console in Real Time?

'test' task does not work for Android plugin, for Android plugin use the following:

// Test Logging
tasks.withType(Test) {
    testLogging {
        events "started", "passed", "skipped", "failed"

See the following:

PHP DateTime __construct() Failed to parse time string (xxxxxxxx) at position x

This worked for me.

     * return date in specific format, given a timestamp.
     * @param  timestamp  $datetime
     * @return string
    public static function showDateString($timestamp)
      if ($timestamp !== NULL) {
        $date = new DateTime();
        return $date->format("d-m-Y");
      return '';

What is the Linux equivalent to DOS pause?

I use these ways a lot that are very short, and they are like @theunamedguy and @Jim solutions, but with timeout and silent mode in addition.

I especially love the last case and use it in a lot of scripts that run in a loop until the user presses Enter.


  • Enter solution

    read -rsp $'Press enter to continue...\n'
  • Escape solution (with -d $'\e')

    read -rsp $'Press escape to continue...\n' -d $'\e'
  • Any key solution (with -n 1)

    read -rsp $'Press any key to continue...\n' -n 1 key
    # echo $key
  • Question with preselected choice (with -ei $'Y')

    read -rp $'Are you sure (Y/n) : ' -ei $'Y' key;
    # echo $key
  • Timeout solution (with -t 5)

    read -rsp $'Press any key or wait 5 seconds to continue...\n' -n 1 -t 5;
  • Sleep enhanced alias

    read -rst 0.5; timeout=$?
    # echo $timeout


-r specifies raw mode, which don't allow combined characters like "\" or "^".

-s specifies silent mode, and because we don't need keyboard output.

-p $'prompt' specifies the prompt, which need to be between $' and ' to let spaces and escaped characters. Be careful, you must put between single quotes with dollars symbol to benefit escaped characters, otherwise you can use simple quotes.

-d $'\e' specifies escappe as delimiter charater, so as a final character for current entry, this is possible to put any character but be careful to put a character that the user can type.

-n 1 specifies that it only needs a single character.

-e specifies readline mode.

-i $'Y' specifies Y as initial text in readline mode.

-t 5 specifies a timeout of 5 seconds

key serve in case you need to know the input, in -n1 case, the key that has been pressed.

$? serve to know the exit code of the last program, for read, 142 in case of timeout, 0 correct input. Put $? in a variable as soon as possible if you need to test it after somes commands, because all commands would rewrite $?

exclude @Component from @ComponentScan

I had an issue when using @Configuration, @EnableAutoConfiguration and @ComponentScan while trying to exclude specific configuration classes, the thing is it didn't work!

Eventually I solved the problem by using @SpringBootApplication, which according to Spring documentation does the same functionality as the three above in one annotation.

Another Tip is to try first without refining your package scan (without the basePackages filter).

@SpringBootApplication(exclude= {Foo.class})
public class MySpringConfiguration {}

How do I get specific properties with Get-AdUser

using select-object for example:

Get-ADUser -Filter * -SearchBase 'OU=Users & Computers, DC=aaaaaaa, DC=com' -Properties DisplayName | select -expand displayname | Export-CSV "ADUsers.csv" 

Write values in app.config file

Try the following code:

    Configuration config = ConfigurationManager.OpenExeConfiguration(Application.ExecutablePath);
    config.AppSettings.Settings.Add("YourKey", "YourValue");

It worked for me :-)

Kotlin - How to correctly concatenate a String

Yes, you can concatenate using a + sign. Kotlin has string templates, so it's better to use them like:

var fn = "Hello"
var ln = "World"

"$fn $ln" for concatenation.

You can even use method.

mvn command not found in OSX Mavrerick

I got same problem, I tried all above, noting solved my problem. Luckely, I solved the problem this way:

echo $SHELL



If it showing "bash" in output. You have to add env properties in .bashrc file (.bash_profile i did not tried, you can try) or else
It is showing 'zsh' in output. You have to add env properties in .zshrc file, if not exist already you create one no issue.

Remove a specific character using awk or sed

tr can be more concise for removing characters than sed or awk, especially when you want to remove different characters from a string.

Removing double quotes:

echo '"Hi"' | tr -d \"
# Produces Hi without quotes

Removing different kinds of brackets:

echo '[{Hi}]' | tr -d {}[]
# Produces Hi without brackets

-d stands for "delete".

Difference between "Complete binary tree", "strict binary tree","full binary Tree"?

Full binary tree are a complete binary tree but reverse is not possible, and if the depth of the binary is n the no. of nodes in the full binary tree is ( 2^n-1 ). It is not necessary in the binary tree that it have two child but in the full binary it every node have no or two child.

How to use if, else condition in jsf to display image

It is illegal to nest EL expressions: you should inline them. Using JSTL is perfectly valid in your situation. Correcting the mistake, you'll make the code working:

<html xmlns="" xmlns:c="">
    <c:if test="#{not empty user or user.userId eq 0}">
        <a href="Images/thumb_02.jpg" target="_blank" ></a>
        <img src="Images/thumb_02.jpg" />
    <c:if test="#{empty user or user.userId eq 0}">
        <a href="/DisplayBlobExample?userId=#{user.userId}" target="_blank"></a>
        <img src="/DisplayBlobExample?userId=#{user.userId}" />

Another solution is to specify all the conditions you want inside an EL of one element. Though it could be heavier and less readable, here it is:

<a href="#{not empty user or user.userId eq 0 ? '/Images/thumb_02.jpg' : '/DisplayBlobExample?userId='}#{not empty user or user.userId eq 0 ? '' : user.userId}" target="_blank"></a>
<img src="#{not empty user or user.userId eq 0 ? '/Images/thumb_02.jpg' : '/DisplayBlobExample?userId='}#{not empty user or user.userId eq 0 ? '' : user.userId}" target="_blank"></img>

How to submit an HTML form without redirection

Place a hidden iFrame at the bottom of your page and target it in your form:

<iframe name="hiddenFrame" width="0" height="0" border="0" style="display: none;"></iframe>

<form action="/Car/Edit/17" id="myForm" method="post" name="myForm" target="hiddenFrame"> ... </form>

Quick and easy. Keep in mind that while the target attribute is still widely supported (and supported in HTML5), it was deprecated in HTML 4.01.

So you really should be using Ajax to future-proof.

How to read file from relative path in Java project? cannot find the path specified

InputStream in = FileLoader.class.getResourceAsStream("<relative path from this class to the file to be read>");
try {
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
    String line = null;
        while ((line = reader.readLine()) != null) {
} catch (Exception e) {

TCP vs UDP on video stream

Besides all the other reasons, UDP can use multicast. Supporting 1000s of TCP users all transmitting the same data wastes bandwidth. However, there is another important reason for using TCP.

TCP can much more easily pass through firewalls and NATs. Depending on your NAT and operator, you may not even be able to receive a UDP stream due to problems with UDP hole punching.

How to convert image to byte array


using System.IO;

byte[] img = File.ReadAllBytes(openFileDialog1.FileName);

Detect HTTP or HTTPS then force HTTPS in JavaScript

How about this?

if (window.location.protocol !== 'https:') {
    window.location = 'https://' + window.location.hostname + window.location.pathname + window.location.hash;

Ideally you'd do it on the server side, though.

Authenticating against Active Directory with Java on Linux

Here's the code I put together based on example from this blog: LINK and this source: LINK.

import com.sun.jndi.ldap.LdapCtxFactory;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Iterator;
import javax.naming.Context;
import javax.naming.AuthenticationException;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import static;

class App2 {

    public static void main(String[] args) {

        if (args.length != 4 && args.length != 2) {
            System.out.println("Purpose: authenticate user against Active Directory and list group membership.");
            System.out.println("Usage: App2 <username> <password> <domain> <server>");
            System.out.println("Short usage: App2 <username> <password>");
            System.out.println("(short usage assumes 'xyz.tld' as domain and 'abc' as server)");

        String domainName;
        String serverName;

        if (args.length == 4) {
            domainName = args[2];
            serverName = args[3];
        } else {
            domainName = "xyz.tld";
            serverName = "abc";

        String username = args[0];
        String password = args[1];

                .println("Authenticating " + username + "@" + domainName + " through " + serverName + "." + domainName);

        // bind by using the specified username/password
        Hashtable props = new Hashtable();
        String principalName = username + "@" + domainName;
        props.put(Context.SECURITY_PRINCIPAL, principalName);
        props.put(Context.SECURITY_CREDENTIALS, password);
        DirContext context;

        try {
            context = LdapCtxFactory.getLdapCtxInstance("ldap://" + serverName + "." + domainName + '/', props);
            System.out.println("Authentication succeeded!");

            // locate this user's record
            SearchControls controls = new SearchControls();
            NamingEnumeration<SearchResult> renum =,
                    "(& (userPrincipalName=" + principalName + ")(objectClass=user))", controls);
            if (!renum.hasMore()) {
                System.out.println("Cannot locate user information for " + username);
            SearchResult result =;

            List<String> groups = new ArrayList<String>();
            Attribute memberOf = result.getAttributes().get("memberOf");
            if (memberOf != null) {// null if this user belongs to no group at all
                for (int i = 0; i < memberOf.size(); i++) {
                    Attributes atts = context.getAttributes(memberOf.get(i).toString(), new String[] { "CN" });
                    Attribute att = atts.get("CN");


            System.out.println("User belongs to: ");
            Iterator ig = groups.iterator();
            while (ig.hasNext()) {
                System.out.println("   " +;

        } catch (AuthenticationException a) {
            System.out.println("Authentication failed: " + a);
        } catch (NamingException e) {
            System.out.println("Failed to bind to LDAP / get account information: " + e);

    private static String toDC(String domainName) {
        StringBuilder buf = new StringBuilder();
        for (String token : domainName.split("\\.")) {
            if (token.length() == 0)
                continue; // defensive check
            if (buf.length() > 0)
        return buf.toString();


Adding ASP.NET MVC5 Identity Authentication to an existing project

I recommend IdentityServer.This is a .NET Foundation project and covers many issues about authentication and authorization.


IdentityServer is a .NET/Katana-based framework and hostable component that allows implementing single sign-on and access control for modern web applications and APIs using protocols like OpenID Connect and OAuth2. It supports a wide range of clients like mobile, web, SPAs and desktop applications and is extensible to allow integration in new and existing architectures.

For more information, e.g.

  • support for MembershipReboot and ASP.NET Identity based user stores
  • support for additional Katana authentication middleware (e.g. Google, Twitter, Facebook etc)
  • support for EntityFramework based persistence of configuration
  • support for WS-Federation
  • extensibility

check out the documentation and the demo.

phpmailer - The following SMTP Error: Data not accepted

set phpmailer to work in debug to see the "real" error behind the generic message 'SMTP Error: data not accepted' in our case the text in the message was triggering the smtp server spam filter.

  $email->SMTPDebug = true;

Recursively find all files newer than a given time

You can find every file what is created/modified in the last day, use this example:

find /directory -newermt $(date +%Y-%m-%d -d '1 day ago') -type f -print

for finding everything in the last week, use '1 week ago' or '7 day ago' anything you want

How to pass macro definition from "make" command line arguments (-D) to C source code?

Just use a specific variable for that.

$ cat Makefile 
    echo foo | gcc $(USER_DEFINES) -E -xc - 

$ make USER_DEFINES="-Dfoo=one"
echo foo | gcc -Dfoo=one -E -xc - 

$ make USER_DEFINES="-Dfoo=bar"
echo foo | gcc -Dfoo=bar -E -xc - 

$ make 
echo foo | gcc  -E -xc - 

Get input type="file" value when it has multiple files selected

The files selected are stored in an array: [input].files

For example, you can access the items

// assuming there is a file input with the ID `my-input`...
var files = document.getElementById("my-input").files;

for (var i = 0; i < files.length; i++)

For jQuery-comfortable people, it's similarly easy

// assuming there is a file input with the ID `my-input`...
var files = $("#my-input")[0].files;

for (var i = 0; i < files.length; i++)

How to check if NSString begins with a certain character

hasPrefix works especially well. for example if you were looking for a http url in a NSString, you would use componentsSeparatedByString to create an NSArray and the iterate the array using hasPrefix to find the elements that begin with http.

NSArray *allStringsArray = 
   [myStringThatHasHttpUrls componentsSeparatedByString:@" "]

for (id myArrayElement in allStringsArray) {
    NSString *theString = [myArrayElement description];
    if ([theString hasPrefix:@"http"]) {
        NSLog(@"The URL  is %@", [myArrayElement description]);


hasPrefix returns a Boolean value that indicates whether a given string matches the beginning characters of the receiver.

- (BOOL)hasPrefix:(NSString *)aString, 

parameter aString is a string that you are looking for Return Value is YES if aString matches the beginning characters of the receiver, otherwise NO. Returns NO if aString is empty.

Jenkins: Failed to connect to repository

In our case git had to be installed on the Jenkins server.

jQuery.parseJSON throws “Invalid JSON” error due to escaped single quote in JSON

According to the state machine diagram on the JSON website, only escaped double-quote characters are allowed, not single-quotes. Single quote characters do not need to be escaped:

Update - More information for those that are interested:

Douglas Crockford does not specifically say why the JSON specification does not allow escaped single quotes within strings. However, during his discussion of JSON in Appendix E of JavaScript: The Good Parts, he writes:

JSON's design goals were to be minimal, portable, textual, and a subset of JavaScript. The less we need to agree on in order to interoperate, the more easily we can interoperate.

So perhaps he decided to only allow strings to be defined using double-quotes since this is one less rule that all JSON implementations must agree on. As a result, it is impossible for a single quote character within a string to accidentally terminate the string, because by definition a string can only be terminated by a double-quote character. Hence there is no need to allow escaping of a single quote character in the formal specification.

Digging a little bit deeper, Crockford's org.json implementation of JSON for Java is more permissible and does allow single quote characters:

The texts produced by the toString methods strictly conform to the JSON syntax rules. The constructors are more forgiving in the texts they will accept:


  • Strings may be quoted with ' (single quote).

This is confirmed by the JSONTokener source code. The nextString method accepts escaped single quote characters and treats them just like double-quote characters:

public String nextString(char quote) throws JSONException {
    char c;
    StringBuffer sb = new StringBuffer();
    for (;;) {
        c = next();
        switch (c) {


        case '\\':
            c =;
            switch (c) {


            case '"':
            case '\'':
            case '\\':
            case '/':

At the top of the method is an informative comment:

The formal JSON format does not allow strings in single quotes, but an implementation is allowed to accept them.

So some implementations will accept single quotes - but you should not rely on this. Many popular implementations are quite restrictive in this regard and will reject JSON that contains single quoted strings and/or escaped single quotes.

Finally to tie this back to the original question, jQuery.parseJSON first attempts to use the browser's native JSON parser or a loaded library such as json2.js where applicable (which on a side note is the library the jQuery logic is based on if JSON is not defined). Thus jQuery can only be as permissive as that underlying implementation:

parseJSON: function( data ) {

    // Attempt to parse using the native JSON parser first
    if ( window.JSON && window.JSON.parse ) {
        return window.JSON.parse( data );


    jQuery.error( "Invalid JSON: " + data );

As far as I know these implementations only adhere to the official JSON specification and do not accept single quotes, hence neither does jQuery.

Boolean Field in Oracle

In our databases we use an enum that ensures we pass it either TRUE or FALSE. If you do it either of the first two ways it is too easy to either start adding new meaning to the integer without going through a proper design, or ending up with that char field having Y, y, N, n, T, t, F, f values and having to remember which section of code uses which table and which version of true it is using.

How to update record using Entity Framework Core?

public async Task<bool> Update(MyObject item)
    Context.Entry(await Context.MyDbSet.FirstOrDefaultAsync(x => x.Id == item.Id)).CurrentValues.SetValues(item);
    return (await Context.SaveChangesAsync()) > 0;

Suppress InsecureRequestWarning: Unverified HTTPS request is being made in Python2.6

That's probably useful for someone, who uses unittest, if imported modules use request library. To suppress warnings in requests' vendored urllib3, add

warnings.filterwarnings('ignore', message='Unverified HTTPS request')

to setUp method in your testclass, i.e:

import unittest, warnings

class MyTests(unittest.TestCase):
    def setUp(self):
        warnings.filterwarnings('ignore', message='Unverified HTTPS request')
    (all test methods here)

Is there a .NET/C# wrapper for SQLite?

Here are the ones I can find:


Push method in React Hooks (useState)?

I tried the above methods for pushing an object into an array of objects in useState but had the following error when using TypeScript:

Type 'TxBacklog[] | undefined' must have a 'Symbol.iterator' method that returns an iterator.ts(2488)

The setup for the tsconfig.json was apparently right:

   "compilerOptions": {
   "target": "es6",
   "lib": [

This workaround solved the problem (my sample code):


   interface TxBacklog {
      status: string,
      txHash: string,

State variable:

    const [txBacklog, setTxBacklog] = React.useState<TxBacklog[]>();

Push new object into array:

    // Define new object to be added
    const newTx = {
       txHash: '0x368eb7269eb88ba86..',
       status: 'pending'
    // Push new object into array
       ? setTxBacklog(prevState => [ ...prevState!, newTx ])
       : setTxBacklog([newTx]);

How to add "on delete cascade" constraints?

Based off of @Mike Sherrill Cat Recall's answer, this is what worked for me:

ALTER TABLE "Children"
DROP CONSTRAINT "Children_parentId_fkey",
ADD CONSTRAINT "Children_parentId_fkey"
  FOREIGN KEY ("parentId")
  REFERENCES "Parent"(id)

How to write a link like <a href="#id"> which link to the same page in PHP?


Are you trying to do sth like this? See:

See the working example:

<a href="#id">go to id</a>
<div style="margin-top:2000px;"></div>
<a id="id">id</a>

What is the use of the init() usage in JavaScript?

In JavaScript when you create any object through a constructor call like below

step 1 : create a function say Person..

function Person(name){;

step 2 : create an instance for this function..

var obj=new Person('venkat')

//above line will instantiate this function(Person) and return a brand new object called Person {name:'venkat'}

if you don't want to instantiate this function and call at same time.we can also do like below..

var Person = {
  init: function(name){;
  print: function(){
var obj=Object.create(Person);

in the above method init will help in instantiating the object properties. basically init is like a constructor call on your class.

Pass multiple parameters to rest API - Spring

you can pass multiple params in url like


and in order to get this query fields , you can use map like

    @RequestMapping(method = RequestMethod.GET, value = "/custom")
    public String controllerMethod(@RequestParam Map<String, String> customQuery) {

        System.out.println("customQuery = brand " + customQuery.containsKey("brand"));
        System.out.println("customQuery = limit " + customQuery.containsKey("limit"));
        System.out.println("customQuery = price " + customQuery.containsKey("price"));
        System.out.println("customQuery = other " + customQuery.containsKey("other"));
        System.out.println("customQuery = sort " + customQuery.containsKey("sort"));

        return customQuery.toString();

Add property to an array of objects

With ES6 you can simply do:

 for(const element of Results) {
      element.Active = "false";

CSS: background image on background color

You need to use the full property name for each:

background-color: #6DB3F2;
background-image: url('images/checked.png');

Or, you can use the background shorthand and specify it all in one line:

background: url('images/checked.png'), #6DB3F2;

How to open a file / browse dialog using javascript?

I worked it around through this "hiding" div ...

<div STYLE="position:absolute;display:none;"><INPUT type='file' id='file1' name='files[]'></div>

WCF gives an unsecured or incorrectly secured fault error

For what it's worth - I also had this error and found it was caused by the connection string in the web services web.config being set to connect to the wrong machine.

java.lang.Exception: No runnable methods exception in running JUnits

the solution is simple if you importing

import org.junit.Test;

you have to run as junit 4

right click ->run as->Test config-> test runner-> as junit 4

WebSocket connection failed: Error during WebSocket handshake: Unexpected response code: 400

In your controller, you are using an http scheme, but I think you should be using a ws scheme, as you are using websockets. Try to use ws://localhost:3000 in your connect function.

Display rows with one or more NaN values in pandas dataframe

Use df[df.isnull().any(axis=1)] for python 3.6 or above.

How to avoid Sql Query Timeout

You could put an index on MemberType.

jquery : focus to div is not working

you can use the below code to bring focus to a div, in this example the page scrolls to the <div id="navigation">

$('html, body').animate({ scrollTop: $('#navigation').offset().top }, 'slow');

Failing to run jar file from command line: “no main manifest attribute”

The -jar option only works if the JAR file is an executable JAR file, which means it must have a manifest file with a Main-Class attribute in it.

If it's not an executable JAR, then you'll need to run the program with something like:

java -cp app.jar com.somepackage.SomeClass

where com.somepackage.SomeClass is the class that contains the main method to run the program.

How to return a result from a VBA function

Just setting the return value to the function name is still not exactly the same as the Java (or other) return statement, because in java, return exits the function, like this:

public int test(int x) {
    if (x == 1) {
        return 1; // exits immediately

    // still here? return 0 as default.
    return 0;

In VB, the exact equivalent takes two lines if you are not setting the return value at the end of your function. So, in VB the exact corollary would look like this:

Public Function test(ByVal x As Integer) As Integer
    If x = 1 Then
        test = 1 ' does not exit immediately. You must manually terminate...
        Exit Function ' to exit
    End If

    ' Still here? return 0 as default.
    test = 0
    ' no need for an Exit Function because we're about to exit anyway.
End Function 

Since this is the case, it's also nice to know that you can use the return variable like any other variable in the method. Like this:

Public Function test(ByVal x As Integer) As Integer

    test = x ' <-- set the return value

    If test <> 1 Then ' Test the currently set return value
        test = 0 ' Reset the return value to a *new* value
    End If

End Function 

Or, the extreme example of how the return variable works (but not necessarily a good example of how you should actually code)—the one that will keep you up at night:

Public Function test(ByVal x As Integer) As Integer

    test = x ' <-- set the return value

    If test > 0 Then

        test = test(test - 1)

    End If

End Function

splitting a string based on tab in the file

Split on tab, but then remove all blank matches.

text = "hi\tthere\t\t\tmy main man"
print [splits for splits in text.split("\t") if splits is not ""]


['hi', 'there', 'my main man']

Whether a variable is undefined

function my_url (base, opt)
    var retval = ["" + base];
    retval.push( opt.page_name ? "&page_name=" + opt.page_name : "");
    retval.push( opt.table_name ? "&table_name=" + opt.table_name : "");
    retval.push( opt.optionResult ? "&optionResult=" + opt.optionResult : "");
    return retval.join("");

my_url("?z=z",  { page_name : "pageX" /* no table_name and optionResult */ } );

/* Returns:

This avoids using typeof whatever === "undefined". (Also, there isn't any string concatenation.)

Find stored procedure by name

Very neat trick I stumble upon trying some SQL injection, in object explorer in the search box just use your percentage characters, and this will search EVERYTHING stored procedures, functions, views, tables, schema, indexes...I tired of thinking of more :)

Search Pattern

How do I find if a string starts with another string in Ruby?

Since there are several methods presented here, I wanted to figure out which one was fastest. Using Ruby 1.9.3p362:

irb(main):001:0> require 'benchmark'
=> true
irb(main):002:0> Benchmark.realtime { 1.upto(10000000) { "foobar"[/\Afoo/] }}
=> 12.477248
irb(main):003:0> Benchmark.realtime { 1.upto(10000000) { "foobar" =~ /\Afoo/ }}
=> 9.593959
irb(main):004:0> Benchmark.realtime { 1.upto(10000000) { "foobar"["foo"] }}
=> 9.086909
irb(main):005:0> Benchmark.realtime { 1.upto(10000000) { "foobar".start_with?("foo") }}
=> 6.973697

So it looks like start_with? ist the fastest of the bunch.

Updated results with Ruby 2.2.2p95 and a newer machine:

require 'benchmark' do |x|'regex[]')    { 10000000.times { "foobar"[/\Afoo/] }}'regex')      { 10000000.times { "foobar" =~ /\Afoo/ }}'[]')         { 10000000.times { "foobar"["foo"] }}'start_with') { 10000000.times { "foobar".start_with?("foo") }}

            user       system     total       real
regex[]     4.020000   0.000000   4.020000 (  4.024469)
regex       3.160000   0.000000   3.160000 (  3.159543)
[]          2.930000   0.000000   2.930000 (  2.931889)
start_with  2.010000   0.000000   2.010000 (  2.008162)

Factory Pattern. When to use factory methods?

One situation where I personally find separate Factory classes to make sense is when the final object you are trying to create relies on several other objects. E.g, in PHP: Suppose you have a House object, which in turn has a Kitchen and a LivingRoom object, and the LivingRoom object has a TV object inside as well.

The simplest method to achieve this is having each object create their children on their construct method, but if the properties are relatively nested, when your House fails creating you will probably spend some time trying to isolate exactly what is failing.

The alternative is to do the following (dependency injection, if you like the fancy term):

$TVObj = new TV($param1, $param2, $param3);
$LivingroomObj = new LivingRoom($TVObj, $param1, $param2);
$KitchenroomObj = new Kitchen($param1, $param2);
$HouseObj = new House($LivingroomObj, $KitchenroomObj);

Here if the process of creating a House fails there is only one place to look, but having to use this chunk every time one wants a new House is far from convenient. Enter the Factories:

class HouseFactory {
    public function create() {
        $TVObj = new TV($param1, $param2, $param3);
        $LivingroomObj = new LivingRoom($TVObj, $param1, $param2);
        $KitchenroomObj = new Kitchen($param1, $param2);
        $HouseObj = new House($LivingroomObj, $KitchenroomObj);

        return $HouseObj;

$houseFactory = new HouseFactory();
$HouseObj = $houseFactory->create();

Thanks to the factory here the process of creating a House is abstracted (in that you don't need to create and set up every single dependency when you just want to create a House) and at the same time centralized which makes it easier to maintain. There are other reasons why using separate Factories can be beneficial (e.g. testability) but I find this specific use case to illustrate best how Factory classes can be useful.

Error: Generic Array Creation

Besides the way suggested in the "possible duplicate", the other main way of getting around this problem is for the array itself (or at least a template of one) to be supplied by the caller, who will hopefully know the concrete type and can thus safely create the array.

This is the way methods like ArrayList.toArray(T[]) are implemented. I'd suggest you take a look at that method for inspiration. Better yet, you should probably be using that method anyway as others have noted.

Difference in boto3 between resource, client, and session?

I'll try and explain it as simple as possible. So there is no guarantee of the accuracy of the actual terms.

Session is where to initiate the connectivity to AWS services. E.g. following is default session that uses the default credential profile(e.g. ~/.aws/credentials, or assume your EC2 using IAM instance profile )

sqs = boto3.client('sqs')
s3 = boto3.resource('s3')

Because default session is limit to the profile or instance profile used, sometimes you need to use the custom session to override the default session configuration (e.g. region_name, endpoint_url, etc. ) e.g.

# custom resource session must use boto3.Session to do the override
my_west_session = boto3.Session(region_name = 'us-west-2')
my_east_session = boto3.Session(region_name = 'us-east-1')
backup_s3 = my_west_session.resource('s3')
video_s3 = my_east_session.resource('s3')

# you have two choices of create custom client session. 
backup_s3c = my_west_session.client('s3')
video_s3c = boto3.client("s3", region_name = 'us-east-1')

Resource : This is the high-level service class recommended to be used. This allows you to tied particular AWS resources and passes it along, so you just use this abstraction than worry which target services are pointed to. As you notice from the session part, if you have a custom session, you just pass this abstract object than worrying about all custom regions,etc to pass along. Following is a complicated example E.g.

import boto3 
my_west_session = boto3.Session(region_name = 'us-west-2')
my_east_session = boto3.Session(region_name = 'us-east-1')
backup_s3 = my_west_session.resource("s3")
video_s3 = my_east_session.resource("s3")
backup_bucket = backup_s3.Bucket('backupbucket') 
video_bucket = video_s3.Bucket('videobucket')

# just pass the instantiated bucket object
def list_bucket_contents(bucket):
   for object in bucket.objects.all():


Client is a low level class object. For each client call, you need to explicitly specify the targeting resources, the designated service target name must be pass long. You will lose the abstraction ability.

For example, if you only deal with the default session, this looks similar to boto3.resource.

import boto3 
s3 = boto3.client('s3')

def list_bucket_contents(bucket_name):
   for object in s3.list_objects_v2(Bucket=bucket_name) :


However, if you want to list objects from a bucket in different regions, you need to specify the explicit bucket parameter required for the client.

import boto3 
backup_s3 = my_west_session.client('s3',region_name = 'us-west-2')
video_s3 = my_east_session.client('s3',region_name = 'us-east-1')

# you must pass boto3.Session.client and the bucket name 
def list_bucket_contents(s3session, bucket_name):
   response = s3session.list_objects_v2(Bucket=bucket_name)
   if 'Contents' in response:
     for obj in response['Contents']:

list_bucket_contents(backup_s3, 'backupbucket')
list_bucket_contents(video_s3 , 'videobucket') 

How does Junit @Rule work?

The explanation for how it works:

JUnit wraps your test method in a Statement object so statement and Execute() runs your test. Then instead of calling statement.Execute() directly to run your test, JUnit passes the Statement to a TestRule with the @Rule annotation. The TestRule's "apply" function returns a new Statement given the Statement with your test. The new Statement's Execute() method can call the test Statement's execute method (or not, or call it multiple times), and do whatever it wants before and after.

Now, JUnit has a new Statement that does more than just run the test, and it can again pass that to any more rules before finally calling Execute.

Execute and get the output of a shell command in node.js

You can use the util library that comes with nodejs to get a promise from the exec command and can use that output as you need. Use restructuring to store the stdout and stderr in variables.

const util = require('util');
const exec = util.promisify(require('child_process').exec);

async function lsExample() {
  const {
  } = await exec('ls');
  console.log('stdout:', stdout);
  console.error('stderr:', stderr);

Eclipse Bug: Unhandled event loop exception No more handles

It is hardware problem at all.

If you have nView, turn off Desktop Manager. In case of ATI, turn off HydraVision.

This works fine on Eclipse Kepler (Standard) and Android Developer Tools Edition.

How to determine if a point is in a 2D triangle?

Since there's no JS answer,
Clockwise & Counter-Clockwise solution:

function triangleContains(ax, ay, bx, by, cx, cy, x, y) {

    let det = (bx - ax) * (cy - ay) - (by - ay) * (cx - ax)

    return  det * ((bx - ax) * (y - ay) - (by - ay) * (x - ax)) > 0 &&
            det * ((cx - bx) * (y - by) - (cy - by) * (x - bx)) > 0 &&
            det * ((ax - cx) * (y - cy) - (ay - cy) * (x - cx)) > 0 


EDIT: there was a typo for det computation (cy - ay instead of cx - ax), this is fixed.

function triangleContains(ax, ay, bx, by, cx, cy, x, y) {_x000D_
    let det = (bx - ax) * (cy - ay) - (by - ay) * (cx - ax)_x000D_
    return  det * ((bx - ax) * (y - ay) - (by - ay) * (x - ax)) > 0 &&_x000D_
            det * ((cx - bx) * (y - by) - (cy - by) * (x - bx)) > 0 &&_x000D_
            det * ((ax - cx) * (y - cy) - (ay - cy) * (x - cx)) > 0 _x000D_
let width = 500, height = 500_x000D_
// clockwise_x000D_
let triangle1 = {_x000D_
 A : { x: 10, y: -10 },_x000D_
 C : { x: 20, y: 100 },_x000D_
 B : { x: -90, y: 10 },_x000D_
 color: '#f00',_x000D_
// counter clockwise_x000D_
let triangle2 = {_x000D_
 A : { x: 20, y: -60 },_x000D_
 B : { x: 90, y: 20 },_x000D_
 C : { x: 20, y: 60 },_x000D_
 color: '#00f',_x000D_
let scale = 2_x000D_
let mouse = { x: 0, y: 0 }_x000D_
// DRAW >_x000D_
let wrapper = document.querySelector('div.wrapper')_x000D_
wrapper.onmousemove = ({ layerX:x, layerY:y }) => {_x000D_
 x -= width / 2_x000D_
 y -= height / 2_x000D_
 x /= scale_x000D_
 y /= scale_x000D_
 mouse.x = x_x000D_
 mouse.y = y_x000D_
function drawArrow(ctx, A, B) {_x000D_
 let v = normalize(sub(B, A), 3)_x000D_
 let I = center(A, B)_x000D_
 let p_x000D_
 p = add(I, rotate(v, 90), v)_x000D_
 ctx.moveTo(p.x, p.y)_x000D_
 ctx.lineTo(I.x, I .y)_x000D_
 p = add(I, rotate(v, -90), v)_x000D_
 ctx.lineTo(p.x, p.y)_x000D_
function drawTriangle(ctx, { A, B, C, color }) {_x000D_
 ctx.moveTo(A.x, A.y)_x000D_
 ctx.lineTo(B.x, B.y)_x000D_
 ctx.lineTo(C.x, C.y)_x000D_
 ctx.fillStyle = color + '6'_x000D_
 ctx.strokeStyle = color_x000D_
 drawArrow(ctx, A, B)_x000D_
 drawArrow(ctx, B, C)_x000D_
 drawArrow(ctx, C, A)_x000D_
function contains({ A, B, C }, P) {_x000D_
 return triangleContains(A.x, A.y, B.x, B.y, C.x, C.y, P.x, P.y)_x000D_
function resetCanvas(canvas) {_x000D_
 canvas.width = width_x000D_
 canvas.height = height_x000D_
 let ctx = canvas.getContext('2d')_x000D_
 ctx.clearRect(0, 0, width, height)_x000D_
 ctx.setTransform(scale, 0, 0, scale, width/2, height/2)_x000D_
function drawDots() {_x000D_
 let canvas = document.querySelector('canvas#dots')_x000D_
 let ctx = canvas.getContext('2d')_x000D_
 let count = 1000_x000D_
 for (let i = 0; i < count; i++) {_x000D_
  let x = width * (Math.random() - .5)_x000D_
  let y = width * (Math.random() - .5)_x000D_
  ctx.ellipse(x, y, 1, 1, 0, 0, 2 * Math.PI)_x000D_
  if (contains(triangle1, { x, y })) {_x000D_
   ctx.fillStyle = '#f00'_x000D_
  } else if (contains(triangle2, { x, y })) {_x000D_
   ctx.fillStyle = '#00f'_x000D_
  } else {_x000D_
   ctx.fillStyle = '#0003'_x000D_
function drawInteractive() {_x000D_
 let canvas = document.querySelector('canvas#interactive')_x000D_
 let ctx = canvas.getContext('2d')_x000D_
 ctx.moveTo(0, -height/2)_x000D_
 ctx.lineTo(0, height/2)_x000D_
 ctx.moveTo(-width/2, 0)_x000D_
 ctx.lineTo(width/2, 0)_x000D_
 ctx.strokeStyle = '#0003'_x000D_
 drawTriangle(ctx, triangle1)_x000D_
 drawTriangle(ctx, triangle2)_x000D_
 ctx.ellipse(mouse.x, mouse.y, 4, 4, 0, 0, 2 * Math.PI)_x000D_
 if (contains(triangle1, mouse)) {_x000D_
  ctx.fillStyle = triangle1.color + 'a'_x000D_
 } else if (contains(triangle2, mouse)) {_x000D_
  ctx.fillStyle = triangle2.color + 'a'_x000D_
 } else {_x000D_
  ctx.strokeStyle = 'black'_x000D_
// trigo_x000D_
function add(...points) {_x000D_
 let x = 0, y = 0_x000D_
 for (let point of points) {_x000D_
  x += point.x_x000D_
  y += point.y_x000D_
 return { x, y }_x000D_
function center(...points) {_x000D_
 let x = 0, y = 0_x000D_
 for (let point of points) {_x000D_
  x += point.x_x000D_
  y += point.y_x000D_
 x /= points.length_x000D_
 y /= points.length_x000D_
 return { x, y }_x000D_
function sub(A, B) {_x000D_
 let x = A.x - B.x_x000D_
 let y = A.y - B.y_x000D_
 return { x, y }_x000D_
function normalize({ x, y }, length = 10) {_x000D_
 let r = length / Math.sqrt(x * x + y * y)_x000D_
 x *= r_x000D_
 y *= r_x000D_
 return { x, y }_x000D_
function rotate({ x, y }, angle = 90) {_x000D_
 let length = Math.sqrt(x * x + y * y)_x000D_
 angle *= Math.PI / 180_x000D_
 angle += Math.atan2(y, x)_x000D_
 x = length * Math.cos(angle)_x000D_
 y = length * Math.sin(angle)_x000D_
 return { x, y }_x000D_
* {_x000D_
 margin: 0;_x000D_
html {_x000D_
 font-family: monospace;_x000D_
body {_x000D_
 padding: 32px;_x000D_
_x000D_ {_x000D_
 color: #f00;_x000D_
_x000D_ {_x000D_
 color: #00f;_x000D_
canvas {_x000D_
 position: absolute;_x000D_
 border: solid 1px #ddd;_x000D_
<p><span class="red">red triangle</span> is clockwise</p>_x000D_
<p><span class="blue">blue triangle</span> is couter clockwise</p>_x000D_
<div class="wrapper">_x000D_
 <canvas id="dots"></canvas>_x000D_
 <canvas id="interactive"></canvas>_x000D_

enter image description here

I'm using here the same method as described above: a point is inside ABC if it is respectively on the "same" side of each line AB, BC, CA.

triangle inclusion example

How to get document height and width without using jquery

How to find out the document width and height very easily?

<span id="hidden_placer" style="position:absolute;right:0;bottom:0;visibility:hidden;"></span>

in javascript

     var c=document.querySelector('#hidden_placer');

     var r=c.getBoundingClientRect();
     r.right=document width
     r.bottom=document height`

You may update this on every window resize event, if needed.

What Are The Best Width Ranges for Media Queries

best bet is targeting features not devices unless you have to, bootstrap do well and you can extend on their breakpoints, for instance targeting pixel density and larger screens above 1920

addEventListener for keydown on Canvas

Edit - This answer is a solution, but a much simpler and proper approach would be setting the tabindex attribute on the canvas element (as suggested by hobberwickey).

You can't focus a canvas element. A simple work around this, would be to make your "own" focus.

var lastDownTarget, canvas;
window.onload = function() {
    canvas = document.getElementById('canvas');

    document.addEventListener('mousedown', function(event) {
        lastDownTarget =;
    }, false);

    document.addEventListener('keydown', function(event) {
        if(lastDownTarget == canvas) {
    }, false);


Is there a better way to refresh WebView?

Why not to try this?

Swift code to call inside class:


or external call


Right way to split an std::string into a vector<string>

std::vector<std::string> split(std::string text, char delim) {
    std::string line;
    std::vector<std::string> vec;
    std::stringstream ss(text);
    while(std::getline(ss, line, delim)) {
    return vec;

split("String will be split", ' ') -> {"String", "will", "be", "split"}

split("Hello, how are you?", ',') -> {"Hello", "how are you?"}

EDIT: Here's a thing I made, this can use multi-char delimiters, albeit I'm not 100% sure if it always works:

std::vector<std::string> split(std::string text, std::string delim) {
    std::vector<std::string> vec;
    size_t pos = 0, prevPos = 0;
    while (1) {
        pos = text.find(delim, prevPos);
        if (pos == std::string::npos) {
            return vec;

        vec.push_back(text.substr(prevPos, pos - prevPos));
        prevPos = pos + delim.length();

Dynamically create checkbox with JQuery from text input

<div id="cblist">
    <input type="checkbox" value="first checkbox" id="cb1" /> <label for="cb1">first checkbox</label>

<input type="text" id="txtName" />
<input type="button" value="ok" id="btnSave" />

<script type="text/javascript">
$(document).ready(function() {
    $('#btnSave').click(function() {

function addCheckbox(name) {
   var container = $('#cblist');
   var inputs = container.find('input');
   var id = inputs.length+1;

   $('<input />', { type: 'checkbox', id: 'cb'+id, value: name }).appendTo(container);
   $('<label />', { 'for': 'cb'+id, text: name }).appendTo(container);

How to convert an Array to a Set in Java

new HashSet<Object>(Arrays.asList(Object[] a));

But I think this would be more efficient:

final Set s = new HashSet<Object>();    
for (Object o : a) { s.add(o); }         

IOS 7 Navigation Bar text and arrow color

[[UINavigationBar appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor whiteColor]}];

How do you specify table padding in CSS? ( table, not cell padding )

CSS doesn't really allow you to do this on a table level. Generally, I specify cellspacing="3" when I want to achieve this effect. Obviously not a css solution, so take it for what it's worth.

Is there an effective tool to convert C# code to Java code?

I'm not sure what you are trying to do by wishing to convert C# to java, but if it is .net interoperability that you need, you might want to check out Mono

Windows.history.back() + location.reload() jquery

Try these ...





Installing SetupTools on 64-bit Windows

Here is a link to another post/thread. I was able run this script to automate registration of Python 2.7. (Make sure to run it from the Python 2.x .exe you want to register!)

To register Python 3.x I had to modify the print syntax and import winreg (instead of _winreg), then run the Python 3 .exe.

What is The difference between ListBox and ListView

Listview derives from listbox control. One most important difference is listview uses the extended selection mode by default . listview also adds a property called view which enables you to customize the view in a richer way than a custom itemspanel. One real life example of listview with gridview is file explorer's details view. Listview with grid view is a less powerful data grid. After the introduction of datagrid control listview lost its importance.

reStructuredText tool support

Salvaging (and extending) the list from an old version of the Wikipedia page:



Although the reference implementation of reStructuredText is written in Python, there are reStructuredText parsers in other languages too.

Python - Docutils

The main distribution of reStructuredText is the Python Docutils package. It contains several conversion tools:

  • rst2html - from reStructuredText to HTML
  • rst2xml - from reStructuredText to XML
  • rst2latex - from reStructuredText to LaTeX
  • rst2odt - from reStructuredText to ODF Text (word processor) document.
  • rst2s5 - from reStructuredText to S5, a Simple Standards-based Slide Show System
  • rst2man - from reStructuredText to Man page

Haskell - Pandoc

Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. It can read Markdown and (subsets of) reStructuredText, HTML, and LaTeX, and it can write Markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, groff man pages, and S5 HTML slide shows.

There is an Pandoc online tool (POT) to try this library. Unfortunately, compared to the reStructuredText online renderer (ROR),

  • POT truncates input rather more shortly. The POT user must render input in chunks that could be rendered whole by the ROR.
  • POT output lacks the helpful error messages displayed by the ROR (and generated by docutils)

Java - JRst

JRst is a Java reStructuredText parser. It can currently output HTML, XHTML, DocBook xdoc and PDF, BUT seems to have serious problems: neither PDF or (X)HTML generation works using the current full download, result pages in (X)HTML are empty and PDF generation fails on IO problems with XSL files (not bundled??). Note that the original JRst has been removed from the website; a fork is found on GitHub.

Scala - Laika

Laika is a new library for transforming markup languages to other output formats. Currently it supports input from Markdown and reStructuredText and produce HTML output. The library is written in Scala but should be also usable from Java.





The Nim compiler features the commands rst2htmland rst2tex which transform reStructuredText files to HTML and TeX files. The standard library provides the following modules (used by the compiler) to handle reStructuredText files programmatically:

  • rst - implements a reStructuredText parser
  • rstast - implements an AST for the reStructuredText parser
  • rstgen - implements a generator of HTML/Latex from reStructuredText

Other 3rd party converters

Most (but not all) of these tools are based on Docutils (see above) and provide conversion to or from formats that might not be supported by the main distribution.

From reStructuredText

  • restview - This pip-installable python package requires docutils, which does the actual rendering. restview's major ease-of-use feature is that, when you save changes to your document(s), it automagically re-renders and re-displays them. restview
    1. starts a small web server
    2. calls docutils to render your document(s) to HTML
    3. calls your device's browser to display the output HTML.
  • rst2pdf - from reStructuredText to PDF
  • rst2odp - from reStructuredText to ODF Presentation
  • rst2beamer - from reStructuredText to LaTeX beamer Presentation class
  • Wikir - from reStructuredText to a Google (and possibly other) Wiki formats
  • rst2qhc - Convert a collection of reStructuredText files into a Qt (toolkit) Help file and (optional) a Qt Help Project file

To reStructuredText

  • xml2rst is an XSLT script to convert Docutils internal XML representation (back) to reStructuredText
  • Pandoc (see above) can also convert from Markdown, HTML and LaTeX to reStructuredText
  • db2rst is a simple and limited DocBook to reStructuredText translator
  • pod2rst - convert .pod files to reStructuredText files


Some projects use reStructuredText as a baseline to build on, or provide extra functionality extending the utility of the reStructuredText tools.


The Sphinx documentation generator translates a set of reStructuredText source files into various output formats, automatically producing cross-references, indices etc.


rest2web is a simple tool that lets you build your website from a single template (or as many as you want), and keep the contents in reStructuredText.


Pygments is a generic syntax highlighter for general use in all kinds of software such as forum systems, Wikis or other applications that need to prettify source code. See Using Pygments in reStructuredText documents.

Free Editors

While any plain text editor is suitable to write reStructuredText documents, some editors have better support than others.


The Emacs support via rst-mode comes as part of the Docutils package under /docutils/tools/editors/emacs/rst.el


The vim-common package for that comes with most GNU/Linux distributions has reStructuredText syntax highlight and indentation support of reStructuredText out of the box:


There is a rst mode for the Jed programmers editor.


gedit, the official text editor of the GNOME desktop environment. There is a gedit reStructuredText plugin.


Geany, a small and lightweight Integrated Development Environment include support for reStructuredText from version 0.12 (October 10, 2007).


Leo, an outlining editor for programmers, supports reStructuredText via rst-plugin or via "@auto-rst" nodes (it's not well-documented, but @auto-rst nodes allow editing rst files directly, parsing the structure into the Leo outline).

It also provides a way to preview the resulting HTML, in a "viewrendered" pane.


The FTE Folding Text Editor - a free (licensed under the GNU GPL) text editor for developers. FTE has a mode for reStructuredText support. It provides color highlighting of basic RSTX elements and special menu that provide easy way to insert most popular RSTX elements to a document.


PyK is a successor of PyEdit and reStInPeace, written in Python with the help of the Qt4 toolkit.


The Eclipse IDE with the ReST Editor plug-in provides support for editing reStructuredText files.


NoTex is a browser based (general purpose) text editor, with integrated project management and syntax highlighting. Plus it enables to write books, reports, articles etc. using rST and convert them to LaTex, PDF or HTML. The PDF files are of high publication quality and are produced via Sphinx with the Texlive LaTex suite.


Notepad++ is a general purpose text editor for Windows. It has syntax highlighting for many languages built-in and support for reStructuredText via a user defined language for reStructuredText.

Visual Studio Code

Visual Studio Code is a general purpose text editor for Windows/macOS/Linux. It has syntax highlighting for many languages built-in and supports reStructuredText via an extension from LeXtudio.

Dedicated reStructuredText Editors

Proprietary editors

Sublime Text

Sublime Text is a completely customizable and extensible source code editor available for Windows, OS X, and Linux. Registration is required for long-term use, but all functions are available in the unregistered version, with occasional reminders to purchase a license. Versions 2 and 3 (currently in beta) support reStructuredText syntax highlighting by default, and several plugins are available through the package manager Package Control to provide snippets and code completion, additional syntax highlighting, conversion to/from RST and other formats, and HTML preview in the browser.

BBEdit / TextWrangler

BBEdit (and its free variant TextWrangler) for Mac can syntax-highlight reStructuredText using this codeless language module.


TextMate, a proprietary general-purpose GUI text editor for Mac OS X, has a bundle for reStructuredText.


Intype is a proprietary text editor for Windows, that support reStructuredText out of the box.

E Text Editor

E is a proprietary Text Editor licensed under the "Open Company License". It supports TextMate's bundles, so it should support reStructuredText the same way TextMate does.


PyCharm (and other IntelliJ platform IDEs?) has ReST/Sphinx support (syntax highlighting, autocomplete and preview).instant preview)


here are some Wiki programs that support the reStructuredText markup as the native markup syntax, or as an add-on:


MediaWiki reStructuredText extension allows for reStructuredText markup in MediaWiki surrounded by <rst> and </rst>.


MoinMoin is an advanced, easy to use and extensible WikiEngine with a large community of users. Said in a few words, it is about collaboration on easily editable web pages.

There is a reStructuredText Parser for MoinMoin.


Trac is an enhanced wiki and issue tracking system for software development projects. There is a reStructuredText Support in Trac.

This Wiki

This Wiki is a Webware for Python Wiki written by Ian Bicking. This wiki uses ReStructuredText for its markup.


rstiki is a minimalist single-file personal wiki using reStructuredText syntax (via docutils) inspired by pwyky. It does not support authorship indication, versioning, hierarchy, chrome/framing/templating or styling. It leverages docutils/reStructuredText as the wiki syntax. As such, it's under 200 lines of code, and in a single file. You put it in a directory and it runs.


Ikiwiki is a wiki compiler. It converts wiki pages into HTML pages suitable for publishing on a website. Ikiwiki stores pages and history in a revision control system such as Subversion or Git. There are many other features, including support for blogging, as well as a large array of plugins. It's reStructuredText plugin, however is somewhat limited and is not recommended as its' main markup language at this time.

Web Services


An Online reStructuredText editor can be used to play with the markup and see the results immediately.

Blogging frameworks


WordPreSt reStructuredText plugin for WordPress. (PHP)


reStructuredText parser plugin for Zine (will become obsolete in version 0.2 when Zine is scheduled to get a native reStructuredText support). Zine is discontinued. (Python)


Pelican is a static blog generator that supports writing articles in ReST. (Python)


Hyde is a static website generator that supports ReST. (Python)


Acrylamid is a static blog generator that supports writing articles in ReST. (Python)


Nikola is a Static Site and Blog Generator that supports ReST. (Python)

ipsum genera

Ipsum genera is a static blog generator written in Nim.


Yozuch is a static blog generator written in Python.


Date Difference in php on days?

strtotime will convert your date string to a unix time stamp. (seconds since the unix epoch.

$ts1 = strtotime($date1);
$ts2 = strtotime($date2);

$seconds_diff = $ts2 - $ts1;

How to increase memory limit for PHP over 2GB?

For others who are experiencing with the same problem, here is the description of the bug in php + patch

Hibernate: failed to lazily initialize a collection of role, no session or session was closed

Your trying to load the lazy loaded collection, but the hibernate session is closed or unavailable. the best solution for this problem, change the lazy loaded object to eager fetch = FetchType.EAGER loading. this problem will solve.

Android: ListView elements with multiple clickable buttons

The solution to this is actually easier than I thought. You can simply add in your custom adapter's getView() method a setOnClickListener() for the buttons you're using.

Any data associated with the button has to be added with myButton.setTag() in the getView() and can be accessed in the onClickListener via view.getTag()

I posted a detailed solution on my blog as a tutorial.

How to create Drawable from resource

Your Activity should have the method getResources. Do:

Drawable myIcon = getResources().getDrawable( R.drawable.icon );

As of API version 21 this method is deprecated and can be replaced with:

Drawable myIcon = AppCompatResources.getDrawable(context, R.drawable.icon);

If you need to specify a custom theme, the following will apply it, but only if API is version 21 or greater:

Drawable myIcon =  ResourcesCompat.getDrawable(getResources(), R.drawable.icon, theme);

Difference between window.location.href and top.location.href

top object makes more sense inside frames. Inside a frame, window refers to current frame's window while top refers to the outermost window that contains the frame(s). So:

window.location.href = 'somepage.html'; means loading somepage.html inside the frame.

top.location.href = 'somepage.html'; means loading somepage.html in the main browser window.

Two other interesting objects are self and parent.

Groovy executing shell commands

command = "ls *"

def execute_state=sh(returnStdout: true, script: command)

but if the command failure the process will terminate

Running Java Program from Command Line Linux

(This is the KISS answer.)

Let's say you have several .java files in the current directory:

$ ls -1 *.java

Let's say each of them have a main() method (so they are programs, not libs), then to compile them do:

javac *.java -d .

This will generate as many subfolders as "packages" the .java files are associated to. In my case all java files where inside under the same package name packageName, so only one folder was generated with that name, so to execute each of them:

java -cp . packageName.javaFileName1
java -cp . packageName.javaFileName2

How to access parent scope from within a custom directive *with own scope* in AngularJS?

See What are the nuances of scope prototypal / prototypical inheritance in AngularJS?

To summarize: the way a directive accesses its parent ($parent) scope depends on the type of scope the directive creates:

  1. default (scope: false) - the directive does not create a new scope, so there is no inheritance here. The directive's scope is the same scope as the parent/container. In the link function, use the first parameter (typically scope).

  2. scope: true - the directive creates a new child scope that prototypically inherits from the parent scope. Properties that are defined on the parent scope are available to the directive scope (because of prototypal inheritance). Just beware of writing to a primitive scope property -- that will create a new property on the directive scope (that hides/shadows the parent scope property of the same name).

  3. scope: { ... } - the directive creates a new isolate/isolated scope. It does not prototypically inherit the parent scope. You can still access the parent scope using $parent, but this is not normally recommended. Instead, you should specify which parent scope properties (and/or function) the directive needs via additional attributes on the same element where the directive is used, using the =, @, and & notation.

  4. transclude: true - the directive creates a new "transcluded" child scope, which prototypically inherits from the parent scope. If the directive also creates an isolate scope, the transcluded and the isolate scopes are siblings. The $parent property of each scope references the same parent scope.
    Angular v1.3 update: If the directive also creates an isolate scope, the transcluded scope is now a child of the isolate scope. The transcluded and isolate scopes are no longer siblings. The $parent property of the transcluded scope now references the isolate scope.

The above link has examples and pictures of all 4 types.

You cannot access the scope in the directive's compile function (as mentioned here: You can access the directive's scope in the link function.


For 1. and 2. above: normally you specify which parent property the directive needs via an attribute, then $watch it:

<div my-dir attr1="prop1"></div>
scope.$watch(attrs.attr1, function() { ... });

If you are watching an object property, you'll need to use $parse:

<div my-dir attr2="obj.prop2"></div>
var model = $parse(attrs.attr2);
scope.$watch(model, function() { ... });

For 3. above (isolate scope), watch the name you give the directive property using the @ or = notation:

<div my-dir attr3="{{prop3}}" attr4="obj.prop4"></div>
scope: {
  localName3: '@attr3',
  attr4:      '='  // here, using the same name as the attribute
link: function(scope, element, attrs) {
   scope.$watch('localName3', function() { ... });
   scope.$watch('attr4',      function() { ... });

Why is my locally-created script not allowed to run under the RemoteSigned execution policy?

this code line was working in Ubuntu with virtualbox and with Win 10 as a virtual os , inside of the powershell

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

If it is not working I recomand to read this resources below :


Module: Microsoft.PowerShell.Security Sets the PowerShell execution policies for Windows computers.,Get%2DExecutionPolicy%20with%20no%20parameters.

Get-ExecutionPolicy -List

How to resize JLabel ImageIcon?

Try this :

ImageIcon imageIcon = new ImageIcon("./img/imageName.png"); // load the image to a imageIcon
Image image = imageIcon.getImage(); // transform it 
Image newimg = image.getScaledInstance(120, 120,  java.awt.Image.SCALE_SMOOTH); // scale it the smooth way  
imageIcon = new ImageIcon(newimg);  // transform it back

(found it here)

Sometimes adding a WCF Service Reference generates an empty reference.cs

As @dblood points out, the main pain is in the DataContractSerializer, that doens't correctly re-use the types. There are already some answers here so I'll start by adding some pro's and cons about these:

  • The 'IsReference' flag causes a lot of trouble, but removing it isn't always the answer (specifically: in situations with recursion).
  • The underlying issue is that the data contract is somehow not the same as the type names, even though they sometimes are (huh? Yes, you read that right!). Apparently the serializer is quite picky and it's very hard to find the real issue.
  • Removing the 'references checks' from the 'Configure service reference' works, but leaves you with a multiple implementations. However, I often reuse SOAP interfaces across DLL's. Also, in most mature SOA's that I know, multiple services interfaces implement and extend the same interface classes. Removing 'use referenced types' checks results in a situation where you cannot simply pass objects around anymore.

Fortunately, if you are in control of your service, there is a simple solution that solves all these issues. This means you can still re-use service interfaces across DLL's - which is IMO a must-have for a proper solution. This is how the solution works:

  1. Create a separate interface DLL. In that DLL, include all DataContract and ServiceContract's; put ServiceContract's on your interfaces.
  2. Derive the server implementation from the interface.
  3. Use the same DLL to construct the client using your favorite method. For example (IMyInterface is the service contract interface):

    var httpBinding = new BasicHttpBinding();
    var identity = new DnsEndpointIdentity("");
    var address = new EndpointAddress(url, identity, new AddressHeaderCollection());
    var channel = new ChannelFactory<IMyInterface>(httpBinding, address);
    return channel.CreateChannel();

In other words: Don't use the 'add service reference' functionality, but force WCF to use the (correct) service types by bypassing the proxy generation. After all, you already have these classes.


  1. You bypass the svcutil.exe process, which means you don't have any IsReference issues
  2. DataContract types and names are correct by definition; after all, both server and client use the very same definition.
  3. If you extend the API or use types from another DLL, (1) and (2) still hold, so you won't run in any trouble there.


  1. A-sync methods are a pain, since you don't generate an a-sync proxy. As a result, I wouldn't recommend doing this in Silverlight applications.

What's the difference between SortedList and SortedDictionary?

This is visual representation of how performances compare to each other.

How to play or open *.mp3 or *.wav sound file in c++ program?

I would use FMOD to do this for your game. It has the ability to play any file mostly for sounds and is pretty simple to implement in C++. using FMOD and Dir3ect X together can be powerful and not that difficult. If you are familiar with Singleton classes I would create a Singleton class of a sound manager in your win main cpp and then have access to it whenever to load or play new music or sound effects. here's an audio manager example

    #pragma once


#include <string>
#include <Windows.h>
#include "fmod.h"
#include "fmod.hpp"
#include "fmod_codec.h"
#include "fmod_dsp.h"
#include "fmod_errors.h"
#include "fmod_memoryinfo.h"
#include "fmod_output.h"

class AudioManager
    // Destructor

    void Initialize(void);  // Initialize sound components
    void Shutdown(void);    // Shutdown sound components

    // Singleton instance manip methods
    static AudioManager* GetInstance(void);
    static void DestroyInstance(void);

    // Accessors
    FMOD::System* GetSystem(void)
        {return soundSystem;}

    // Sound playing
    void Play(FMOD::Sound* sound);  // Play a sound/music with default channel
    void PlaySFX(FMOD::Sound* sound);   // Play a sound effect with custom channel
    void PlayBGM(FMOD::Sound* sound);   // Play background music with custom channel

    // Volume adjustment methods
    void SetBGMVolume(float volume);
    void SetSFXVolume(float volume);

    static AudioManager* instance;  // Singleton instance
    AudioManager(void);  // Constructor

    FMOD::System* soundSystem;  // Sound system object
    FMOD_RESULT result;
    FMOD::Channel* bgmChannel;  // Channel for background music
    static const int numSfxChannels = 4;
    FMOD::Channel* sfxChannels[numSfxChannels]; // Channel for sound effects


Update Android SDK Tool to 22.0.4(Latest Version) from 22.0.1

Have you tried this ? Download preview channel. After that, install ADT Preview.

Saving response from Requests to file

I believe all the existing answers contain the relevant information, but I would like to summarize.

The response object that is returned by requests get and post operations contains two useful attributes:

Response attributes

  • response.text - Contains str with the response text.
  • response.content - Contains bytes with the raw response content.

You should choose one or other of these attributes depending on the type of response you expect.

  • For text-based responses (html, json, yaml, etc) you would use response.text
  • For binary-based responses (jpg, png, zip, xls, etc) you would use response.content.

Writing response to file

When writing responses to file you need to use the open function with the appropriate file write mode.

  • For text responses you need to use "w" - plain write mode.
  • For binary responses you need to use "wb" - binary write mode.


Text request and save

# Request the HTML for this web page:
response = requests.get("")
with open("response.txt", "w") as f:

Binary request and save

# Request the profile picture of the OP:
response = requests.get("")
with open("response.jpg", "wb") as f:

Answering the original question

The original code should work by using wb and response.content:

import requests

files = {'f': ('1.pdf', open('1.pdf', 'rb'))}
response ="",files=files)
response.raise_for_status() # ensure we notice bad responses
file = open("out.xls", "wb")

But I would go further and use the with context manager for open.

import requests

with open('1.pdf', 'rb') as file:
    files = {'f': ('1.pdf', file)}
    response ="",files=files)

response.raise_for_status() # ensure we notice bad responses

with open("out.xls", "wb") as file:

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

I had the same problem , and i found the solution , and it works like a charm

just set the flag multi to true like this :

                {_id_receiver: id_receiver},
               {$set: {is_showed: true}},
                {multi: true}   /* --> multiple update */
            , function (err, updated) {...});

i hope that helps :)

Difference of keywords 'typename' and 'class' in templates?

This piece of snippet is from c++ primer book. Although I am sure this is wrong.

Each type parameter must be preceded by the keyword class or typename:

// error: must precede U with either typename or class
template <typename T, U> T calc(const T&, const U&);

These keywords have the same meaning and can be used interchangeably inside a template parameter list. A template parameter list can use both keywords:

// ok: no distinction between typename and class in a template parameter list
template <typename T, class U> calc (const T&, const U&);

It may seem more intuitive to use the keyword typename rather than class to designate a template type parameter. After all, we can use built-in (nonclass) types as a template type argument. Moreover, typename more clearly indicates that the name that follows is a type name. However, typename was added to C++ after templates were already in widespread use; some programmers continue to use class exclusively

View not attached to window manager crash

Override onDestroy of the Activity and Dismiss your Dialog & make it null

protected void onDestroy ()
        if(mProgressDialog != null)
        mProgressDialog= null;

How do you install Google frameworks (Play, Accounts, etc.) on a Genymotion virtual device?

Google Apps KitKat for Genymotion.

Download the Google Apps ZIP file from the link which contain the essential Google Apps such as Play Store, Gmail, YouTube, etc.

After finishing booting, drag and drop the ZIP file we downloaded named to the Genymotion Window. It starts installing the Google Apps, and it asks for your confirmation. Confirm it.

Syntax behind sorted(key=lambda: ...)

Simple and not time consuming answer with an example relevant to the question asked Follow this example:

 user = [{"name": "Dough", "age": 55}, 
            {"name": "Ben", "age": 44}, 
            {"name": "Citrus", "age": 33},
            {"name": "Abdullah", "age":22},
    print(sorted(user, key=lambda el: el["name"]))
    print(sorted(user, key= lambda y: y["age"]))

Look at the names in the list, they starts with D, B, C and A. And if you notice the ages, they are 55, 44, 33 and 22. The first print code

print(sorted(user, key=lambda el: el["name"]))

Results to:

[{'name': 'Abdullah', 'age': 22}, 
{'name': 'Ben', 'age': 44}, 
{'name': 'Citrus', 'age': 33}, 
{'name': 'Dough', 'age': 55}]

sorts the name, because by key=lambda el: el["name"] we are sorting the names and the names return in alphabetical order.

The second print code

print(sorted(user, key= lambda y: y["age"]))


[{'name': 'Abdullah', 'age': 22},
 {'name': 'Citrus', 'age': 33},
 {'name': 'Ben', 'age': 44}, 
 {'name': 'Dough', 'age': 55}]

sorts by age, and hence the list returns by ascending order of age.

Try this code for better understanding.

Creating and throwing new exception

You can throw your own custom errors by extending the Exception class.

class CustomException : Exception {
    [string] $additionalData

    CustomException($Message, $additionalData) : base($Message) {
        $this.additionalData = $additionalData

try {
    throw [CustomException]::new('Error message', 'Extra data')
} catch [CustomException] {
    # NOTE: To access your custom exception you must use $_.Exception
    Write-Output $_.Exception.additionalData

    # This will produce the error message: Didn't catch it the second time
    throw [CustomException]::new("Didn't catch it the second time", 'Extra data')

GSON throwing "Expected BEGIN_OBJECT but was BEGIN_ARRAY"?

Alternative could be

to make your response look like


      "updated_at":"2012-03-02 21:06:01",
      "fetched_at":"2012-03-02 21:28:37.728840",
      "modified":"2012-03-02 23:28:58.840076"
      "updated_at":"2012-03-02 14:07:44",
      "fetched_at":"2012-03-02 21:28:37.033108",
      "modified":"2012-03-02 23:28:57.928001"

instead of


      "updated_at":"2012-03-02 21:06:01",
      "fetched_at":"2012-03-02 21:28:37.728840",
      "modified":"2012-03-02 23:28:58.840076"
      "updated_at":"2012-03-02 14:07:44",
      "fetched_at":"2012-03-02 21:28:37.033108",
      "modified":"2012-03-02 23:28:57.928001"


  String server_JSONResponse =.... // the string in which you are getting your JSON Response after hitting URL
String myCustom_JSONResponse="";// in which we will keep our response after adding object element to it
     MyClass apiResponse = new MyClass();


    apiResponse = gson.fromJson(myCustom_JSONResponse, MyClass .class);

After this it will be just any other GSON Parsing

C# static class why use?

If a class is declared as static then the variables and methods need to be declared as static.

A class can be declared static, indicating that it contains only static members. It is not possible to create instances of a static class using the new keyword. Static classes are loaded automatically by the .NET Framework common language runtime (CLR) when the program or namespace containing the class is loaded.

Use a static class to contain methods that are not associated with a particular object. For example, it is a common requirement to create a set of methods that do not act on instance data and are not associated to a specific object in your code. You could use a static class to hold those methods.

->The main features of a static class are:

  • They only contain static members.
  • They cannot be instantiated.
  • They are sealed.
  • They cannot contain Instance Constructors or simply constructors as we know that they are associated with objects and operates on data when an object is created.


static class CollegeRegistration
  //All static member variables
   static int nCollegeId; //College Id will be same for all the students studying
   static string sCollegeName; //Name will be same
   static string sColegeAddress; //Address of the college will also same

    //Member functions
   public static int GetCollegeId()
     nCollegeId = 100;
     return (nCollegeID);
    //similarly implementation of others also.
} //class end

public class student
    int nRollNo;
    string sName;

    public GetRollNo()
       nRollNo += 1;
       return (nRollNo);
    //similarly ....
    public static void Main()
     //Not required.
     //CollegeRegistration objCollReg= new CollegeRegistration();

     int cid= CollegeRegistration.GetCollegeId();
    string sname= CollegeRegistration.GetCollegeName();

   } //Main end

Migrating from VMWARE to VirtualBox

After many attempts I was finally able to get this working. Essentially what I did was download and use the vmware converter to merge the two disks into one. After that I was able to attach the newly created disk to VitrualBox.

The steps involved are very simple:


1) MAKE A BACKUP!!! Even if you follow these instruction, you could screw things up, so make a backup. Just shutdown the VM and then make a copy of the directory where VM resides.

2) Uninstall VMware Tools from the VM that you are going to convert. If for some reason you forget this step, you can still uninstall it after getting everything running under VirtualBox by following these steps. Do yourself the favor and just do it now.


1) Download and install the VMware Converter. I used 5.0.1 build-875114, just use the latest.

2) Download and install VirtualBox

3) Fire up VMWare convertor:

Fire up VMWare convertor

4) Click on Convert machine

6) Browse to the .vmx for your VM and click Next.

Convert machine

7) Give the new VM a name and select the location where you want to put it. Click Next

Give the new VM a name and select the location

8) Click Next on the Options screen. You shouldn't have to change anything here.

Click <code>Next</code> on the <code>Options</code> screen.

9) Click Finish on the Summary screen to begin the conversion.

Click <code>Finish</code> on the <code>Summary</code> screen

10) The conversion should start. This will take a LOOONG time so be patient.

The conversion should start.

11) Hopefully all went well, if it did, you should see that the conversion is completed:

conversion is completed

12) Now open up VirtualBox and click New.

open up VirtualBox and click <code>New</code>

13) Give your VM a name and select what Type and Version it is. Click Next.

Give your VM a name and select what <code>Type</code> and <code>Version</code> it is.

14) Select the size of the memory you want to give it. Click Next.

Select the size of the memory you want to give it.

15) For the Hard Drive, click Use and existing hard drive file and select the newly converted .vmdk file.

Use and existing hard drive file

16) Now Click Settings and select the Storage menu. The issue is that by default VirtualBox will add the drive as an IDE. This won't work and we need as we need to put it on a SCSI controller.

put it on a SCSI controller

17) Select the IDE controller and the Remove Controller button.

Select the IDE controller and the <code>Remove Controller</code> button.

18) Now click the Add Controller button and select Add SCSI Controller

Add SCSI Controller

19) Click the Add Hard Disk button.

Add Hard Disk

20) Click Choose existing disk

Choose existing disk

21) Select your .vmdk file. Click OK

Select your <code>.vmdk</code> file.

22) Select the System menu.

Select the <code>System</code> menu.

23) Click Enable IO APIC. Then click OK

Click <code>Enable IO APIC</code>.

24) Congrats!!! Your VM is now confgiured! Click Start to startup the VM!

Click <code>Start</code> to startup the VM!

Difference between r+ and w+ in fopen()

The main difference is w+ truncate the file to zero length if it exists or create a new file if it doesn't. While r+ neither deletes the content nor create a new file if it doesn't exist.

Try these codes and you will understand:

#include <stdio.h>
int main()
   FILE *fp;

   fp = fopen("test.txt", "w+");
   fprintf(fp, "This is testing for fprintf...\n");
   fputs("This is testing for fputs...\n", fp);

and then this

#include <stdio.h>
int main()
   FILE *fp;

   fp = fopen("test.txt", "w+");

Then open the file test.txt and see the what happens. You will see that all data written by the first program has been erased.
Repeat this for r+ and see the result. Hope you will understand.

MySQL Insert into multiple tables? (Database normalization?)

This is the way that I did it for a uni project, works fine, prob not safe tho

$dbhost = 'localhost';
$dbuser = 'root';
$dbpass = '';
$conn = mysql_connect($dbhost, $dbuser, $dbpass);

$title =    $_POST['title'];            
$name =     $_POST['name'];         
$surname =  $_POST['surname'];                  
$email =    $_POST['email'];            
$pass =     $_POST['password'];     
$cpass =    $_POST['cpassword'];        

$check = 1;

if (){
    $check = 1;
if ($check == 1){


$sel_user = "SELECT * FROM users WHERE user_email='$email'";
$run_user = mysqli_query($con, $sel_user);
$check_user = mysqli_num_rows($run_user);

if ($check_user > 0){
    echo    '<div style="margin: 0 0 10px 20px;">Email already exists!</br>
             <a href="recover.php">Recover Password</a></div>';
    $users_tb = "INSERT INTO users ". 
           "(user_name, user_email, user_password) ". 

    $users_info_tb = "INSERT INTO users_info".
           "(user_title, user_surname)".
        "VALUES('$title', '$surname')";

    $run_users_tb = mysql_query( $users_tb, $conn );
    $run_users_info_tb = mysql_query( $users_info_tb, $conn );

    if(!$run_users_tb || !$run_users_info_tb){
        die('Could not enter data: ' . mysql_error());
        echo "Entered data successfully\n";



pypi UserWarning: Unknown distribution option: 'install_requires'

sudo apt-get install python-dev  # for python2.x installs
sudo apt-get install python3-dev  # for python3.x installs

It will install any missing headers. It solved my issue

Django request get parameters

You can use [] to extract values from a QueryDict object like you would any ordinary dictionary.

# HTTP POST variables
request.POST['section'] # => [39]
request.POST['MAINS'] # => [137]

# HTTP GET variables
request.GET['section'] # => [39]
request.GET['MAINS'] # => [137]

# HTTP POST and HTTP GET variables (Deprecated since Django 1.7)
request.REQUEST['section'] # => [39]
request.REQUEST['MAINS'] # => [137]

How to simulate a click by using x,y coordinates in JavaScript?

it doenst work for me but it prints the correct element to the console

this is the code:

function click(x, y)
    var ev = new MouseEvent('click', {
        'view': window,
        'bubbles': true,
        'cancelable': true,
        'screenX': x,
        'screenY': y

    var el = document.elementFromPoint(x, y);
    console.log(el); //print element to console
click(400, 400);

Simple jQuery, PHP and JSONP example?

More Suggestion


        url: "http://FullUrl",
        dataType: 'jsonp',
        success: function (data) {

            //Data from the server in the in the variable "data"
            //In the form of an array



PHP CallBack:


$array = array(
     '0' => array('fullName' => 'Meni Samet', 'fullAdress' => 'New York, NY'),
     '1' => array('fullName' => 'Test 2', 'fullAdress' => 'Paris'),

if(isset ($_GET['callback']))
    header("Content-Type: application/json");

    echo $_GET['callback']."(".json_encode($array).")";


iOS 11, 12, and 13 installed certificates not trusted automatically (self signed)

I follow all recommendations and all requirements. I install my self signed root CA on my iPhone. I make it trusted. I put certificate signed with this root CA on my local development server and I still get certificated error on safari iOS. Working on all other platforms.

Exit single-user mode

Not sure if this helps anyone, but I had the same issue and could not find the process that was holding me up. I closed SSMS and stopped all the services hitting the local instance. Then once I went back in and ran the exec sp_who2, it showed me the culprit. I killed the process and was able to get the Multi_User to work, then restart the services. We had IIS hitting it every few minutes/seconds looking for certain packages.

React.js: Wrapping one component into another


var Wrapper = React.createClass({
  render: function() {
    return (
      <div className="wrapper">

See Multiple Components: Children and Type of the Children props in the docs for more info.

How to support HTTP OPTIONS verb in ASP.NET MVC/WebAPI application

I've had same problem, and this is how I fixed it:

Just throw this in your web.config:

      <remove name="WebDAVModule" />

        <add name="Access-Control-Expose-Headers " value="WWW-Authenticate"/>
        <add name="Access-Control-Allow-Origin" value="*" />
        <add name="Access-Control-Allow-Methods" value="GET, POST, OPTIONS, PUT, PATCH, DELETE" />
        <add name="Access-Control-Allow-Headers" value="accept, authorization, Content-Type" />
        <remove name="X-Powered-By" />

      <remove name="WebDAV" />
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

Javascript: open new page in same window

Here's what worked for me:

<button name="redirect" onClick="redirect()">button name</button>
<script type="text/javascript">
function redirect(){
var url = "";, '_top');

AES Encryption for an NSString on the iPhone

Since you haven't posted any code, it's difficult to know exactly which problems you're encountering. However, the blog post you link to does seem to work pretty decently... aside from the extra comma in each call to CCCrypt() which caused compile errors.

A later comment on that post includes this adapted code, which works for me, and seems a bit more straightforward. If you include their code for the NSData category, you can write something like this: (Note: The printf() calls are only for demonstrating the state of the data at various points — in a real application, it wouldn't make sense to print such values.)

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSString *key = @"my password";
    NSString *secret = @"text to encrypt";

    NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding];
    NSData *cipher = [plain AES256EncryptWithKey:key];
    printf("%s\n", [[cipher description] UTF8String]);

    plain = [cipher AES256DecryptWithKey:key];
    printf("%s\n", [[plain description] UTF8String]);
    printf("%s\n", [[[NSString alloc] initWithData:plain encoding:NSUTF8StringEncoding] UTF8String]);

    [pool drain];
    return 0;

Given this code, and the fact that encrypted data will not always translate nicely into an NSString, it may be more convenient to write two methods that wrap the functionality you need, in forward and reverse...

- (NSData*) encryptString:(NSString*)plaintext withKey:(NSString*)key {
    return [[plaintext dataUsingEncoding:NSUTF8StringEncoding] AES256EncryptWithKey:key];

- (NSString*) decryptData:(NSData*)ciphertext withKey:(NSString*)key {
    return [[[NSString alloc] initWithData:[ciphertext AES256DecryptWithKey:key]
                                  encoding:NSUTF8StringEncoding] autorelease];

This definitely works on Snow Leopard, and @Boz reports that CommonCrypto is part of the Core OS on the iPhone. Both 10.4 and 10.5 have /usr/include/CommonCrypto, although 10.5 has a man page for CCCryptor.3cc and 10.4 doesn't, so YMMV.

EDIT: See this follow-up question on using Base64 encoding for representing encrypted data bytes as a string (if desired) using safe, lossless conversions.


Try using:


This should make the lock exclusive and hold it for the duration of the transaction.

How to print to stderr in Python?

Python 2:

print >> sys.stderr, "fatal error"

Python 3:

print("fatal error", file=sys.stderr)

Long answer

print >> sys.stderr is gone in Python3. says:

Old: print >> sys.stderr, "fatal error"
New: print("fatal error", file=sys.stderr)

For many of us, it feels somewhat unnatural to relegate the destination to the end of the command. The alternative

sys.stderr.write("fatal error\n")

looks more object oriented, and elegantly goes from the generic to the specific. But note that write is not a 1:1 replacement for print.

Jquery $(this) Child Selector

The best way with the HTML you have would probably be to use the next function, like so:

var div = $(this).next('.class2');

Since the click handler is happening to the <a>, you could also traverse up to the parent DIV, then search down for the second DIV. You would do this with a combination of parent and children. This approach would be best if the HTML you put up is not exactly like that and the second DIV could be in another location relative to the link:

var div = $(this).parent().children('.class2');

If you wanted the "search" to not be limited to immediate children, you would use find instead of children in the example above.

Also, it is always best to prepend your class selectors with the tag name if at all possible. ie, if only <div> tags are going to have those classes, make the selector be div.class1, div.class2.

How to open Emacs inside Bash

If you need to open Emacs without X:

emacs -nw

How to read a specific line using the specific line number from a file in Java?

You may try indexed-file-reader (Apache License 2.0). The class IndexedFileReader has a method called readLines(int from, int to) which returns a SortedMap whose key is the line number and the value is the line that was read.


File file = new File("src/test/resources/file.txt");
reader = new IndexedFileReader(file);

lines = reader.readLines(6, 10);
assertNotNull("Null result.", lines);
assertEquals("Incorrect length.", 5, lines.size());
assertTrue("Incorrect value.", lines.get(6).startsWith("[6]"));
assertTrue("Incorrect value.", lines.get(7).startsWith("[7]"));
assertTrue("Incorrect value.", lines.get(8).startsWith("[8]"));
assertTrue("Incorrect value.", lines.get(9).startsWith("[9]"));
assertTrue("Incorrect value.", lines.get(10).startsWith("[10]"));      

The above example reads a text file composed of 50 lines in the following format:

[1] The quick brown fox jumped over the lazy dog ODD
[2] The quick brown fox jumped over the lazy dog EVEN

Disclamer: I wrote this library

How do I give PHP write access to a directory?

1st Figure out which user is owning httpd process using the following command

ps aux | grep httpd

you will get a several line response like this:

phpuser   17121  0.0  0.2 414060  7928 ?        SN   03:49   0:00 /usr/sbin/httpd

Here 1st column shows the user name. So now you know the user who is trying to write files, which is in this case phpuser You can now go ahead and set the permission for directory where your php script is trying to write something:

sudo chown phpuser:phpuser PhpCanWriteHere
sudo chmod 755 PhpCanWriteHere

Load HTML page dynamically into div with jQuery

I think this would do it:

<script type="text/javascript" src=""></script>
<script type="text/javascript">

         $("#content").attr("src" , $(this).attr("ref"));


<iframe id="content"></iframe>

<a href="#" ref="page1.html" class="divlink" >Page 1</a><br />
<a href="#" ref="page2.html" class="divlink" >Page 2</a><br />
<a href="#" ref="page3.html" class="divlink" >Page 3</a><br />
<a href="#" ref="page4.html" class="divlink" >Page 4</a><br />
<a href="#" ref="page5.html" class="divlink" >Page 5</a><br />
<a href="#" ref="page6.html" class="divlink" >Page 6</a><br />

By the way if you can avoid Jquery, you can just use the target attribute of <a> element:

<iframe id="content" name="content"></iframe>

<a href="page1.html" target="content" >Page 1</a><br />
<a href="page2.html" target="content" >Page 2</a><br />
<a href="page3.html" target="content" >Page 3</a><br />
<a href="page4.html" target="content" >Page 4</a><br />
<a href="page5.html" target="content" >Page 5</a><br />
<a href="page6.html" target="content" >Page 6</a><br />

How can I get a web site's favicon?

You can get the favicon URL from the website's HTML.

Here is the favicon element:

<link rel="icon" type="image/png" href="/someimage.png" />

You should use a regular expression here. If no tag found, look for favicon.ico in the site root directory. If nothing found, the site does not have a favicon.

SecurityException during executing jnlp file (Missing required Permissions manifest attribute in main jar)

If you'd like to set this globally for all users of a machine, you can create the following directory and file structures:

mkdir %windir%\Sun\Java\Deployment

Create a file deployment.config with the content:


Create a file\:/WINDOWS/Sun/Java/Deployment/exception.sites

Create a file exception.sites


html vertical align the text inside input type button

I've given up trying to align my text on buttons! Now, if I need it, I'm using <a> tags, like so:

<a href="javascript:void();" style="display:block;font-size:1em;padding:5px;cursor:default;" onclick="document.getElementById('form').submit();">Submit</a>

So, if the document's font size is 12px, my "button" will have 22px height. And the text will be vertically align. That in theory, because, in some casses, an unequal padding of "6px 5px 4px 5px" will do the job done.

Although, is a hack, this technique is pretty good for solving compatibility issues in older browsers too, like IE6!

Chosen Jquery Plugin - getting selected values

I believe the problem occurs when targeting by ID, because Chosen will copy the ID from the original select onto it's newly created div, leaving you with 2 elements of the same (now not-unique) ID on the current page.

When targeting Chosen by ID, use a selector specific to the select:

$( 'select#yourID' ).on( 'change', function() {
    console.log( $( this ).val() );
} );

...instead of...

$( '#yourID' ).on( 'change', function() {
    console.log( $( this ).val() );
} );

This works because Chosen mirrors its selected items back to the original (now hidden) select element, even in multi-mode.

(It also continues to work with or without Chosen, say... if you decide to go a different direction in your application.)

How to display list of repositories from subversion server

Sometimes you may wish to check on the timestamp for when the repo was updated, for getting this handy info you can use the svn -v (verbose) option as in

svn list -v svn://

Converting Select results into Insert script - SQL Server

If you are using Oracle (or configure the application to the SQL Server) then Oracle SQL Developer does this for you. choose 'unload' for a table and follow the options through (untick DDL if you don't want all the table create stuff).

permission denied - php unlink

// Path relative to where the php file is or absolute server path
chdir($FilePath); // Comment this out if you are on the same folder
chown($FileName,465); //Insert an Invalid UserId to set to Nobody Owner; for instance 465
$do = unlink($FileName);

    echo "The file was deleted successfully."; 
} else { echo "There was an error trying to delete the file."; } 

Try this. Hope it helps.

Getting value of HTML Checkbox from onclick/onchange events

The short answer:

Use the click event, which won't fire until after the value has been updated, and fires when you want it to:

<label><input type='checkbox' onclick='handleClick(this);'>Checkbox</label>

function handleClick(cb) {
  display("Clicked, new value = " + cb.checked);

Live example | Source

The longer answer:

The change event handler isn't called until the checked state has been updated (live example | source), but because (as Tim Büthe points out in the comments) IE doesn't fire the change event until the checkbox loses focus, you don't get the notification proactively. Worse, with IE if you click a label for the checkbox (rather than the checkbox itself) to update it, you can get the impression that you're getting the old value (try it with IE here by clicking the label: live example | source). This is because if the checkbox has focus, clicking the label takes the focus away from it, firing the change event with the old value, and then the click happens setting the new value and setting focus back on the checkbox. Very confusing.

But you can avoid all of that unpleasantness if you use click instead.

I've used DOM0 handlers (onxyz attributes) because that's what you asked about, but for the record, I would generally recommend hooking up handlers in code (DOM2's addEventListener, or attachEvent in older versions of IE) rather than using onxyz attributes. That lets you attach multiple handlers to the same element and lets you avoid making all of your handlers global functions.

An earlier version of this answer used this code for handleClick:

function handleClick(cb) {
  setTimeout(function() {
    display("Clicked, new value = " + cb.checked);
  }, 0);

The goal seemed to be to allow the click to complete before looking at the value. As far as I'm aware, there's no reason to do that, and I have no idea why I did. The value is changed before the click handler is called. In fact, the spec is quite clear about that. The version without setTimeout works perfectly well in every browser I've tried (even IE6). I can only assume I was thinking about some other platform where the change isn't done until after the event. In any case, no reason to do that with HTML checkboxes.

Any way to break if statement in PHP?

$a = 1;

switch($a) {

  case "1":

    if  ($condition1){

    if  ($condition2){

    if  ($condition3){

In this way I got what I want. I use a switch only has a definite case and then use break in case to choose if condition. The reason why I use the break : condition1 and condition2 may both satisfy, in that situation only condition1 is applied .IF is selective according the order.

javax.persistence.NoResultException: No entity found for query

You mentioned getting the result list from the Query, since you don't know that there is a UniqueResult (hence the exception) you could use list and check the size?

if (query.list().size() == 1) 

Since you're not doing a get() to get your unique object a query will be executed whether you call uniqueResult or list.

How to get 2 digit year w/ Javascript?

The specific answer to this question is found in this one line below:

//pull the last two digits of the year_x000D_
//logs to console_x000D_
//creates a new date object (has the current date and time by default)_x000D_
//gets the full year from the date object (currently 2017)_x000D_
//converts the variable to a string_x000D_
//gets the substring backwards by 2 characters (last two characters)    _x000D_
console.log(new Date().getFullYear().toString().substr(-2));

Formatting Full Date Time Example (MMddyy): jsFiddle


//A function for formatting a date to MMddyy_x000D_
function formatDate(d)_x000D_
    //get the month_x000D_
    var month = d.getMonth();_x000D_
    //get the day_x000D_
    //convert day to string_x000D_
    var day = d.getDate().toString();_x000D_
    //get the year_x000D_
    var year = d.getFullYear();_x000D_
    //pull the last two digits of the year_x000D_
    year = year.toString().substr(-2);_x000D_
    //increment month by 1 since it is 0 indexed_x000D_
    //converts month to a string_x000D_
    month = (month + 1).toString();_x000D_
    //if month is 1-9 pad right with a 0 for two digits_x000D_
    if (month.length === 1)_x000D_
        month = "0" + month;_x000D_
    //if day is between 1-9 pad right with a 0 for two digits_x000D_
    if (day.length === 1)_x000D_
        day = "0" + day;_x000D_
    //return the string "MMddyy"_x000D_
    return month + day + year;_x000D_
var d = new Date();_x000D_

Python Pandas merge only certain columns

You can use .loc to select the specific columns with all rows and then pull that. An example is below:

pandas.merge(dataframe1, dataframe2.iloc[:, [0:5]], how='left', on='key')

In this example, you are merging dataframe1 and dataframe2. You have chosen to do an outer left join on 'key'. However, for dataframe2 you have specified .iloc which allows you to specific the rows and columns you want in a numerical format. Using :, your selecting all rows, but [0:5] selects the first 5 columns. You could use .loc to specify by name, but if your dealing with long column names, then .iloc may be better.

Passing an array by reference in C?

Arrays are effectively passed by reference by default. Actually the value of the pointer to the first element is passed. Therefore the function or method receiving this can modify the values in the array.

void SomeMethod(Coordinate Coordinates[]){Coordinates[0].x++;};
int main(){
  Coordinate tenCoordinates[10];
  if(0==tenCoordinates[0].x - 2;){

The two calls are equivalent, and the exit value should be 0;

Converting from Integer, to BigInteger

You can do in this way:

    Integer i = 1;
    new BigInteger("" + i);

AngularJS - Animate ng-view transitions

Angularjs 1.1.4 has now introduced the ng-animate directive to help animating different elements, in particular ng-view.

You can also watch the video about this new featue

UPDATE as of angularjs 1.2, the way animations work has changed drastically, most of it is now controlled with CSS, without having to setup javascript callbacks, etc.. You can check the updated tutorial on Year Of Moo. @dfsq pointed out in the comments a nice set of examples.