Programs & Examples On #Rewriting

Repeatedly applying rules to transform objects

How to test the type of a thrown exception in Jest

In case you are working with Promises:

await expect(Promise.reject(new HttpException('Error message', 402)))

Why does "npm install" rewrite package-lock.json?

There is an open issue for this on their github page:

This issue is most severe when developers are using different operating systems.

How to get HttpContext.Current in ASP.NET Core?

There is a solution to this if you really need a static access to the current context. In Startup.Configure(….)

app.Use(async (httpContext, next) =>
    CallContext.LogicalSetData("CurrentContextKey", httpContext);
        await next();

And when you need it you can get it with :

HttpContext context = CallContext.LogicalGetData("CurrentContextKey") as HttpContext;

I hope that helps. Keep in mind this workaround is when you don’t have a choice. The best practice is to use de dependency injection.

Start redis-server with config file

To start redis with a config file all you need to do is specifiy the config file as an argument:

redis-server /root/config/redis.rb

Instead of using and killing PID's I would suggest creating an init script for your service

I would suggest taking a look at the Installing Redis more properly section of It will walk you through setting up an init script with redis so you can just do something like service redis_server start and service redis_server stop to control your server.

I am not sure exactly what distro you are using, that article describes instructions for a Debian based distro. If you are are using a RHEL/Fedora distro let me know, I can provide you with instructions for the last couple of steps, the config file and most of the other steps will be the same.

“tag already exists in the remote" error after recreating the git tag

It seems that I'm late on this issue and/or it has already been answered, but, what could be done is: (in my case, I had only one tag locally so.. I deleted the old tag and retagged it with:

git tag -d v1.0
git tag -a v1.0 -m "My commit message"


git push --tags -f

That will update all tags on remote.

Could be dangerous! Use at own risk.

How do I get the offset().top value of an element without using jQuery?

Here is a function that will do it without jQuery:

function getElementOffset(element)
    var de = document.documentElement;
    var box = element.getBoundingClientRect();
    var top = + window.pageYOffset - de.clientTop;
    var left = box.left + window.pageXOffset - de.clientLeft;
    return { top: top, left: left };

AngularJS: how to enable $locationProvider.html5Mode with deeplinking

My problem solved with these :

1- Add this to your head :

<base href="/" />

2- Use this in app.config


How can I match a string with a regex in Bash?

I don't have enough rep to comment here, so I'm submitting a new answer to improve on dogbane's answer. The dot . in the regexp

[[ sed-4.2.2.tar.bz2 =~ tar.bz2$ ]] && echo matched

will actually match any character, not only the literal dot between 'tar.bz2', for example

[[ sed-4.2.2.tar4bz2 =~ tar.bz2$ ]] && echo matched
[[ sed-4.2.2.tar§bz2 =~ tar.bz2$ ]] && echo matched

or anything that doesn't require escaping with '\'. The strict syntax should then be

[[ sed-4.2.2.tar.bz2 =~ tar\.bz2$ ]] && echo matched

or you can go even stricter and also include the previous dot in the regex:

[[ sed-4.2.2.tar.bz2 =~ \.tar\.bz2$ ]] && echo matched

$location / switching between html5 and hashbang mode / link rewriting

Fur future readers, if you are using Angular 1.6, you also need to change the hashPrefix:

appModule.config(['$locationProvider', function($locationProvider) {

Don't forget to set the base in your HTML <head>:

    <base href="/">

More info about the changelog here.

URL rewriting with PHP

If you only want to change the route for picture.php then adding rewrite rule in .htaccess will serve your needs, but, if you want the URL rewriting as in Wordpress then PHP is the way. Here is simple example to begin with.

Folder structure

There are two files that are needed in the root folder, .htaccess and index.php, and it would be good to place the rest of the .php files in separate folder, like inc/.



RewriteEngine On
RewriteRule ^inc/.*$ index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ index.php [QSA,L]

This file has four directives:

  1. RewriteEngine - enable the rewriting engine
  2. RewriteRule - deny access to all files in inc/ folder, redirect any call to that folder to index.php
  3. RewriteCond - allow direct access to all other files ( like images, css or scripts )
  4. RewriteRule - redirect anything else to index.php


Because everything is now redirected to index.php, there will be determined if the url is correct, all parameters are present, and if the type of parameters are correct.

To test the url we need to have a set of rules, and the best tool for that is a regular expression. By using regular expressions we will kill two flies with one blow. Url, to pass this test must have all the required parameters that are tested on allowed characters. Here are some examples of rules.

$rules = array( 
    'picture'   => "/picture/(?'text'[^/]+)/(?'id'\d+)",    // '/picture/some-text/51'
    'album'     => "/album/(?'album'[\w\-]+)",              // '/album/album-slug'
    'category'  => "/category/(?'category'[\w\-]+)",        // '/category/category-slug'
    'page'      => "/page/(?'page'about|contact)",          // '/page/about', '/page/contact'
    'post'      => "/(?'post'[\w\-]+)",                     // '/post-slug'
    'home'      => "/"                                      // '/'

Next is to prepare the request uri.

$uri = rtrim( dirname($_SERVER["SCRIPT_NAME"]), '/' );
$uri = '/' . trim( str_replace( $uri, '', $_SERVER['REQUEST_URI'] ), '/' );
$uri = urldecode( $uri );

Now that we have the request uri, the final step is to test uri on regular expression rules.

foreach ( $rules as $action => $rule ) {
    if ( preg_match( '~^'.$rule.'$~i', $uri, $params ) ) {
        /* now you know the action and parameters so you can 
         * include appropriate template file ( or proceed in some other way )

Successful match will, since we use named subpatterns in regex, fill the $params array almost the same as PHP fills the $_GET array. However, when using a dynamic url, $_GET array is populated without any checks of the parameters.


        [0] => /picture/some text/51
        [text] => some text
        [1] => some text
        [id] => 51
        [2] => 51


        [text] => some text
        [id] => 51

These few lines of code and a basic knowing of regular expressions is enough to start building a solid routing system.

Complete source

define( 'INCLUDE_DIR', dirname( __FILE__ ) . '/inc/' );

$rules = array( 
    'picture'   => "/picture/(?'text'[^/]+)/(?'id'\d+)",    // '/picture/some-text/51'
    'album'     => "/album/(?'album'[\w\-]+)",              // '/album/album-slug'
    'category'  => "/category/(?'category'[\w\-]+)",        // '/category/category-slug'
    'page'      => "/page/(?'page'about|contact)",          // '/page/about', '/page/contact'
    'post'      => "/(?'post'[\w\-]+)",                     // '/post-slug'
    'home'      => "/"                                      // '/'

$uri = rtrim( dirname($_SERVER["SCRIPT_NAME"]), '/' );
$uri = '/' . trim( str_replace( $uri, '', $_SERVER['REQUEST_URI'] ), '/' );
$uri = urldecode( $uri );

foreach ( $rules as $action => $rule ) {
    if ( preg_match( '~^'.$rule.'$~i', $uri, $params ) ) {
        /* now you know the action and parameters so you can 
         * include appropriate template file ( or proceed in some other way )
        include( INCLUDE_DIR . $action . '.php' );

        // exit to avoid the 404 message 

// nothing is found so handle the 404 error
include( INCLUDE_DIR . '404.php' );

An Authentication object was not found in the SecurityContext - Spring 3.2.2

The security's authorization check part gets the authenticated object from SecurityContext, which will be set when a request gets through the spring security filter. My assumption here is that soon after the login this is not being set. You probably can use a hack as given below to set the value.

try {
    SecurityContext ctx = SecurityContextHolder.createEmptyContext();

    //Do what ever you want to do

} finally {


Also you can have a look at the InteractiveAuthenticationSuccessEvent which will be called once the SecurityContext is set.

How do I configure IIS for URL Rewriting an AngularJS application in HTML5 mode?

The IIS inbound rules as shown in the question DO work. I had to clear the browser cache and add the following line in the top of my <head> section of the index.html page:

<base href="/myApplication/app/" />

This is because I have more than one application in localhost and so requests to other partials were being taken to localhost/app/view1 instead of localhost/myApplication/app/view1

Hopefully this helps someone!

Text-decoration: none not working

Add this statement on your header tag:

  text-decoration: none!important;
  cursor: pointer;

Python AttributeError: 'module' object has no attribute 'Serial'

You have installed the incorrect package named 'serial'.

  • Run pip uninstall serial for python 2.x or pip3 uninstall serial for python 3.x
  • Then install pyserial if not already installed by running pip install pyserial for python 2.x orpip3 install pyserial for python 3.x.

How to shift a column in Pandas DataFrame

If you don't want to lose the columns you shift past the end of your dataframe, simply append the required number first:

    offset = 5
    DF = DF.append([np.nan for x in range(offset)])
    DF = DF.shift(periods=offset)
    DF = DF.reset_index() #Only works if sequential index

Tips for debugging .htaccess rewrite rules

Regarding 4., you still need to ensure that your "dummy script stub" is actually the target URL after all the rewriting is done, or you won't see anything!

A similar/related trick (see this question) is to insert a temporary rule such as:

RewriteRule (.*) /show.php?url=$1 [END]

Where show.php is some very simple script that just displays its $_GET parameters (you can display environment variables too, if you want).

This will stop the rewriting at the point you insert it into the ruleset, rather like a breakpoint in a debugger.

If you're using Apache <2.3.9, you'll need to use [L] rather than [END], and you may then need to add:

RewriteRule ^show.php$ - [L]

At the very top of your ruleset, if the URL /show.php is itself being rewritten.

How to set cache: false in jQuery.get call

Per the JQuery documentation, .get() only takes the url, data (content), dataType, and success callback as its parameters. What you're really looking to do here is modify the jqXHR object before it gets sent. With .ajax(), this is done with the beforeSend() method. But since .get() is a shortcut, it doesn't allow it.

It should be relatively easy to switch your .ajax() calls to .get() calls though. After all, .get() is just a subset of .ajax(), so you can probably use all the default values for .ajax() (except, of course, for beforeSend()).


::Looks at Jivings' answer::

Oh yeah, forgot about the cache parameter! While beforeSend() is useful for adding other headers, the built-in cache parameter is far simpler here.

Initialize a byte array to a certain value, other than the default null?

This is a faster version of the code from the post marked as the answer.

All of the benchmarks that I have performed show that a simple for loop that only contains something like an array fill is typically twice as fast if it is decrementing versus if it is incrementing.

Also, the array Length property is already passed as the parameter so it doesn't need to be retrieved from the array properties. It should also be pre-calculated and assigned to a local variable. Loop bounds calculations that involve a property accessor will re-compute the value of the bounds before each iteration of the loop.

public static byte[] CreateSpecialByteArray(int length)
    byte[] array = new byte[length];

    int len = length - 1;

    for (int i = len; i >= 0; i--)
        array[i] = 0x20;

    return array;

Dynamically adding HTML form field using jQuery

What seems to be confusing this thread is the difference between:

$('.selector').append("<input type='text'/>"); 

Which appends the target element as a child of the .selector.


$("<input type='text' />").appendTo('.selector');

Which appends the target element as a child of the .selector.

Note how the position of the target element & the .selector change when using the different methods.

What you want to do is this:

$(function() {

  // append input control at start of form
  $("<input type='text' value='' />")
     .attr("id", "myfieldid")
     .attr("name", "myfieldid")

  // OR

  // append input control at end of form
  $("<input type='text' value='' />")
     .attr("id", "myfieldid")
     .attr("name", "myfieldid")

  // OR

  // see .after() or .before() in the library


Which ORM should I use for Node.js and MySQL?

I would choose Sequelize because of it's excellent documentation. It's just a honest opinion (I never really used MySQL with Node that much).

Using DataContractSerializer to serialize, but can't deserialize back

I ended up doing the following and it works.

public static string Serialize(object obj)
    using (MemoryStream memoryStream = new MemoryStream())
        DataContractSerializer serializer = new DataContractSerializer(obj.GetType());
        serializer.WriteObject(memoryStream, obj);
        return Encoding.UTF8.GetString(memoryStream.ToArray());

public static object Deserialize(string xml, Type toType)
    using (MemoryStream memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(xml)))
        XmlDictionaryReader reader = XmlDictionaryReader.CreateTextReader(memoryStream, Encoding.UTF8, new XmlDictionaryReaderQuotas(), null);
        DataContractSerializer serializer = new DataContractSerializer(toType);
        return serializer.ReadObject(reader);

It seems that the major problem was in the Serialize function when calling stream.GetBuffer(). Calling stream.ToArray() appears to work.

Could not load file or assembly '***.dll' or one of its dependencies

I had the same issue - a .dll working all the time, then my computer crashed and afterwards I had this problem of 'could not load file or assembly ....dll'

Two possible solutions: when the computer crashed there may be some inconsistent files in

C:\Users\<yourUserName>\AppData\Local\Temp\Temporary ASP.NET Files

Deleting that folder, recompiling and the error was gone.

Once I had also to delete my packages folder (I had read that somewhere else). Allow Visual Studio / nuget to install missing packages (or manually reinstall) and afterwards everything was fine again.

How to permanently remove few commits from remote branch

You git reset --hard your local branch to remove changes from working tree and index, and you git push --force your revised local branch to the remote. (other solution here, involving deleting the remote branch, and re-pushing it)

This SO answer illustrates the danger of such a command, especially if people depends on the remote history for their own local repos.
You need to be prepared to point out people to the RECOVERING FROM UPSTREAM REBASE section of the git rebase man page

With Git 2.23 (August 2019, nine years later), you would use the new command git switch.
That is: git switch -C mybranch origin/mybranch~n
(replace n by the number of commits to remove)

That will restore the index and working tree, like a git reset --hard would.
The documentation adds:

-C <new-branch>
--force-create <new-branch>

Similar to --create except that if <new-branch> already exists, it will be reset to <start-point>.
This is a convenient shortcut for:

$ git branch -f <new-branch>
$ git switch <new-branch>

New to unit testing, how to write great tests?

Don't write tests to get full coverage of your code. Write tests that guarantee your requirements. You may discover codepaths that are unnecessary. Conversely, if they are necessary, they are there to fulfill some kind of requirement; find it what it is and test the requirement (not the path).

Keep your tests small: one test per requirement.

Later, when you need to make a change (or write new code), try writing one test first. Just one. Then you'll have taken the first step in test-driven development.

How to convert unsigned long to string

For a long value you need to add the length info 'l' and 'u' for unsigned decimal integer,

as a reference of available options see sprintf

#include <stdio.h>

    int main ()
      unsigned long lval = 123;
      char buffer [50];
      sprintf (buffer, "%lu" , lval );

Can an XSLT insert the current date?

For MSXML parser, try this:

<xsl:stylesheet version="1.0"
                xmlns:my="urn:sample" extension-element-prefixes="msxml">

    <msxsl:script language="JScript" implements-prefix="my">
       function today()
          return new Date(); 
    <xsl:template match="/">

        Today = <xsl:value-of select="my:today()"/>


Also read XSLT Stylesheet Scripting using msxsl:script and Extending XSLT with JScript, C#, and Visual Basic .NET

Can you change what a symlink points to after it is created?

Just a warning to the correct answers above:

Using the -f / --force Method provides a risk to lose the file if you mix up source and target:

mbucher@server2:~/test$ ls -la
total 11448
drwxr-xr-x  2 mbucher www-data    4096 May 25 15:27 .
drwxr-xr-x 18 mbucher www-data    4096 May 25 15:13 ..
-rw-r--r--  1 mbucher www-data 4109466 May 25 15:26 data.tar.gz
-rw-r--r--  1 mbucher www-data 7582480 May 25 15:27 otherdata.tar.gz
lrwxrwxrwx  1 mbucher www-data      11 May 25 15:26 thesymlink -> data.tar.gz
mbucher@server2:~/test$ ln -s -f thesymlink otherdata.tar.gz 
mbucher@server2:~/test$ ls -la
total 4028
drwxr-xr-x  2 mbucher www-data    4096 May 25 15:28 .
drwxr-xr-x 18 mbucher www-data    4096 May 25 15:13 ..
-rw-r--r--  1 mbucher www-data 4109466 May 25 15:26 data.tar.gz
lrwxrwxrwx  1 mbucher www-data      10 May 25 15:28 otherdata.tar.gz -> thesymlink
lrwxrwxrwx  1 mbucher www-data      11 May 25 15:26 thesymlink -> data.tar.gz

Of course this is intended, but usually mistakes occur. So, deleting and rebuilding the symlink is a bit more work but also a bit saver:

mbucher@server2:~/test$ rm thesymlink && ln -s thesymlink otherdata.tar.gz 
ln: creating symbolic link `otherdata.tar.gz': File exists

which at least keeps my file.

What is a 'multi-part identifier' and why can't it be bound?

Mine was putting the schema on the table Alias by mistake:

SELECT * FROM schema.CustomerOrders co
WHERE = 1  -- oops!

Java - Find shortest path between 2 points in a distance weighted map

You can see a complete example using java 8, recursion and streams -> Dijkstra algorithm with java

String Resource new line /n not possible?

I know this is pretty old question but it topped the list when I searched. So I wanted to update with another method.

In the strings.xml file you can do the \n or you can simply press enter:

<string name="Your string name" > This is your string.

   This is the second line of your string.\n\n Third line of your string.</string>

This will result in the following on your TextView:

This is your string.

This is the second line of your string.

Third line of your string.

This is because there were two returns between the beginning declaration of the string and the new line. I also added the \n to it for clarity, as either can be used. I like to use the carriage returns in the xml to be able to see a list or whatever multiline string I have. My two cents.

Could not load file or assembly 'System.Web.WebPages.Razor, Version=

Apologies in advance for this lo-tech suggestion, but another option, which finally worked for me after battling NuGet for several hours, is to re-create a new empty project, Web API in my case, and just copy the guts of your old, now-broken project into the new one. Took me about 15 minutes.

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

In addition to @chanafdo answer, you can use route name

when working with laravel blade

<a href="{{route('login')}}">login here</a> with parameter in route name

when go to url like URI: profile/{id} <a href="{{route('profile', ['id' => 1])}}">login here</a>

without blade

<a href="<?php echo route('login')?>">login here</a>

with parameter in route name

when go to url like URI: profile/{id} <a href="<?php echo route('profile', ['id' => 1])?>">login here</a>

As of laravel 5.2 you can use @php @endphp to create as <?php ?> in laravel blade. Using blade your personal opinion but I suggest to use it. Learn it. It has many wonderful features as template inheritance, Components & Slots,subviews etc...

What is the easiest way to parse an INI file in Java?

Or with standard Java API you can use java.util.Properties:

Properties props = new Properties();
try (FileInputStream in = new FileInputStream(path)) {

Print a div content using Jquery

I update this function
now you can print any tag or any part of the page with its full style
must include jquery.js file


<div id='DivIdToPrint'>
    <p>This is a sample text for printing purpose.</p>
<p>Do not print.</p>
<input type='button' id='btn' value='Print' onclick='printtag("DivIdToPrint");' >


        function printtag(tagid) {
            var hashid = "#"+ tagid;
            var tagname =  $(hashid).prop("tagName").toLowerCase() ;
            var attributes = ""; 
            var attrs = document.getElementById(tagid).attributes;
                attributes +=  " "+" ='"+elem.value+"' " ;
            var divToPrint= $(hashid).html() ;
            var head = "<html><head>"+ $("head").html() + "</head>" ;
            var allcontent = head + "<body  onload='window.print()' >"+ "<" + tagname + attributes + ">" +  divToPrint + "</" + tagname + ">" +  "</body></html>"  ;
           // setTimeout(function(){newWin.close();},10);

What are the valid Style Format Strings for a Reporting Services [SSRS] Expression?

As mentioned, you can use:

=Format(Fields!Price.Value, "C")

A digit after the "C" will specify precision:

=Format(Fields!Price.Value, "C0")
=Format(Fields!Price.Value, "C1")

You can also use Excel-style masks like this:

=Format(Fields!Price.Value, "#,##0.00")

Haven't tested the last one, but there's the idea. Also works with dates:

=Format(Fields!Date.Value, "yyyy-MM-dd")

split python source code into multiple files?


#file  -- --
myvar = 42
def test_func():

Now, this file ("") is in python terminology a "module". We can import it (as long as it can be found in our PYTHONPATH) Note that the current directory is always in PYTHONPATH, so if use_test is being run from the same directory where lives, you're all set:

#file -- --
import test
test.test_func()  #prints "Hello!"
print (test.myvar)  #prints 42

from test import test_func #Only import the function directly into current namespace
test_func() #prints "Hello"
print (myvar)     #Exception (NameError)

from test import *
test_func() #prints "Hello"
print(myvar)      #prints 42

There's a lot more you can do than just that through the use of special files which allow you to treat multiple files as a single module), but this answers your question and I suppose we'll leave the rest for another time.

How can I get Docker Linux container information from within the container itself?

I believe that the "problem" with all of the above is that it depends upon a certain implementation convention either of docker itself or its implementation and how that interacts with cgroups and /proc, and not via a committed, public, API, protocol or convention as part of the OCI specs.

Hence these solutions are "brittle" and likely to break when least expected when implementations change, or conventions are overridden by user configuration.

container and image ids should be injected into the r/t environment by the component that initiated the container instance, if for no other reason than to permit code running therein to use that information to uniquely identify themselves for logging/tracing etc...

just my $0.02, YMMV...

JSON Parse File Path

This solution uses an Asynchronous call. It will likely work better than a synchronous solution.

var request = new XMLHttpRequest();"GET", "../../data/file.json", false);
request.onreadystatechange = function() {
  if ( request.readyState === 4 && request.status === 200 ) {
    var my_JSON_object = JSON.parse(request.responseText);

How to remove close button on the jQuery UI dialog?


Using gdb to single-step assembly code outside specified executable causes error "cannot find bounds of current function"

Instead of gdb, run gdbtui. Or run gdb with the -tui switch. Or press C-x C-a after entering gdb. Now you're in GDB's TUI mode.

Enter layout asm to make the upper window display assembly -- this will automatically follow your instruction pointer, although you can also change frames or scroll around while debugging. Press C-x s to enter SingleKey mode, where run continue up down finish etc. are abbreviated to a single key, allowing you to walk through your program very quickly.

B+>|0x402670 <main>         push   %r15                                        |
   |0x402672 <main+2>       mov    %edi,%r15d                                  |
   |0x402675 <main+5>       push   %r14                                        |
   |0x402677 <main+7>       push   %r13                                        |
   |0x402679 <main+9>       mov    %rsi,%r13                                   |
   |0x40267c <main+12>      push   %r12                                        |
   |0x40267e <main+14>      push   %rbp                                        |
   |0x40267f <main+15>      push   %rbx                                        |
   |0x402680 <main+16>      sub    $0x438,%rsp                                 |
   |0x402687 <main+23>      mov    (%rsi),%rdi                                 |
   |0x40268a <main+26>      movq   $0x402a10,0x400(%rsp)                       |
   |0x402696 <main+38>      movq   $0x0,0x408(%rsp)                            |
   |0x4026a2 <main+50>      movq   $0x402510,0x410(%rsp)                       |
child process 21518 In: main                            Line: ??   PC: 0x402670
(gdb) file /opt/j64-602/bin/jconsole
Reading symbols from /opt/j64-602/bin/jconsole...done.
(no debugging symbols found)...done.
(gdb) layout asm
(gdb) start

How to find substring inside a string (or how to grep a variable)?

Well, what about something like this:

PS3="Select database or <Q> to quit: "
select DB in db1 db2 db3; do
   [ "${REPLY^*}" = 'Q' ] && break
   echo "Should backup $DB..."

How to change MySQL data directory?

I often need to do this when upgrading machines, moving from box to box. In addition to moving /var/lib/mysql to a better location, I often need to restore old DB tables from an old MySQL installation. In order to do this...

  1. Stop mysql. Follow the instructions above, it necessary.
  2. Copy the database directories -- there will be one for each of your old installation's database -- to the new DATADIR location. But omit "mysql" and "performance_schema" directories.
  3. Correct permissions among the copied database directories. Ownership should be mysql:mysql, directories should be 700, and files should be 660.
  4. Restart mysql. Depending on your installation, old version DB files should be updated.

jQuery click event not working after adding class

on document ready event there is no a tag with class tabclick. so you have to bind click event dynamically when you are adding tabclick class. please this code:

$("a.applicationdata").click(function() {
    var appid = $(this).attr("id");

   $('#gentab a').addClass("tabclick")
    .click(function() {
          var liId = $(this).parent("li").attr("id");

 $('#gentab a').attr('href', '#datacollector');


How to use Microsoft.Office.Interop.Excel on a machine without installed MS Office?

If the "Customer don't want to install and buy MS Office on a server not at any price", then you cannot use Excel ... But I cannot get the trick: it's all about one basic Office licence which costs something like 150 USD ... And I guess that spending time finding an alternative will cost by far more than this amount!

Python String and Integer concatenation

for i in range(11):
    string = "string{0}".format(i)

What you did (range[1,10]) is

  • a TypeError since brackets denote an index (a[3]) or a slice (a[3:5]) of a list,
  • a SyntaxError since [1,10] is invalid, and
  • a double off-by-one error since range(1,10) is [1, 2, 3, 4, 5, 6, 7, 8, 9], and you seem to want [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

And string = "string" + i is a TypeError since you can't add an integer to a string (unlike JavaScript).

Look at the documentation for Python's new string formatting method, it is very powerful.

How do you add an image?

Never mind -- I'm an idiot. I just needed <xsl:value-of select="/root/Image/node()"/>

What are the differences between Deferred, Promise and Future in JavaScript?

  • A promise represents a value that is not yet known
  • A deferred represents work that is not yet finished

A promise is a placeholder for a result which is initially unknown while a deferred represents the computation that results in the value.


What is the difference between `` and `Enum.toString()`?

The main difference between name() and toString() is that name() is a final method, so it cannot be overridden. The toString() method returns the same value that name() does by default, but toString() can be overridden by subclasses of Enum.

Therefore, if you need the name of the field itself, use name(). If you need a string representation of the value of the field, use toString().

For instance:

public enum WeekDay {

    public String toString() {
        return name().charAt(0) + name().substring(1).toLowerCase();

In this example, returns "MONDAY", and WeekDay.MONDAY.toString() returns "Monday".

WeekDay.valueOf( returns WeekDay.MONDAY, but WeekDay.valueOf(WeekDay.MONDAY.toString()) throws an IllegalArgumentException.

How to Set Variables in a Laravel Blade Template

Assign variable to the blade template, Here are the solutions

We can use <?php ?> tag in blade page

<?php $var = 'test'; ?>
{{ $var }


We can use the blade comment with special syntax

{{--*/ $var = 'test' /*--}}
{{ $var }}

Import one schema into another new schema - Oracle

The issue was with the dmp file itself. I had to re-export the file and the command works fine. Thank you @Justin Cave

Unable to convert MySQL date/time value to System.DateTime

If I google for "Unable to convert MySQL date/time value to System.DateTime" I see numerous references to a problem accessing MySQL from Visual Studio. Is that your context?

One solution suggested is:

This is not a bug but expected behavior. Please check manual under connect options and set "Allow Zero Datetime" to true, as on attached pictures, and the error will go away.


How do you convert Html to plain text?

I think the easiest way is to make a 'string' extension method (based on what user Richard have suggested):

using System;
using System.Text.RegularExpressions;

public static class StringHelpers
    public static string StripHTML(this string HTMLText)
            var reg = new Regex("<[^>]+>", RegexOptions.IgnoreCase);
            return reg.Replace(HTMLText, "");

Then just use this extension method on any 'string' variable in your program:

var yourHtmlString = "<div class=\"someclass\"><h2>yourHtmlText</h2></span>";
var yourTextString = yourHtmlString.StripHTML();

I use this extension method to convert html formated comments to plain text so it will be displayed correctly on a crystal report, and it works perfect!

JQuery Validate input file type

So, I had the same issue and sadly just adding to the rules didn't work. I found out that accept: and extension: are not part of JQuery validate.js by default and it requires an additional-Methods.js plugin to make it work.

So for anyone else who followed this thread and it still didn't work, you can try adding additional-Methods.js to your tag in addition to the answer above and it should work.

Node.js getaddrinfo ENOTFOUND

  var http=require('http');
   http.get('', function(res){
        var str = '';
        console.log('Response is '+res.statusCode);

        res.on('data', function (chunk) {
               str += chunk;

        res.on('end', function () {


Directory.GetFiles: how to get only filename, not full path?

Have a look at using FileInfo.Name Property

something like

string[] files = Directory.GetFiles(dir); 

for (int iFile = 0; iFile < files.Length; iFile++)
    string fn = new FileInfo(files[iFile]).Name;

Also have a look at using DirectoryInfo Class and FileInfo Class

Is there "\n" equivalent in VBscript?

This page has a table of string constants including vbCrLf

vbCrLf | Chr(13) & Chr(10) | Carriage return–linefeed combination

Convert comma separated string of ints to int array

You should use a foreach loop, like this:

public static IEnumerable<int> StringToIntList(string str) {
    if (String.IsNullOrEmpty(str))
        yield break;

    foreach(var s in str.Split(',')) {
        int num;
        if (int.TryParse(s, out num))
            yield return num;

Note that like your original post, this will ignore numbers that couldn't be parsed.

If you want to throw an exception if a number couldn't be parsed, you can do it much more simply using LINQ:

return (str ?? "").Split(',').Select<string, int>(int.Parse);

Are PDO prepared statements sufficient to prevent SQL injection?

Yes, it is sufficient. The way injection type attacks work, is by somehow getting an interpreter (The database) to evaluate something, that should have been data, as if it was code. This is only possible if you mix code and data in the same medium (Eg. when you construct a query as a string).

Parameterised queries work by sending the code and the data separately, so it would never be possible to find a hole in that.

You can still be vulnerable to other injection-type attacks though. For example, if you use the data in a HTML-page, you could be subject to XSS type attacks.

Showing all errors and warnings

You can see a detailed description here.

ini_set('display_errors', 1);

// Report simple running errors
error_reporting(E_ERROR | E_WARNING | E_PARSE);

// Reporting E_NOTICE can be good too (to report uninitialized
// variables or catch variable name misspellings ...)
error_reporting(E_ERROR | E_WARNING | E_PARSE | E_NOTICE);

// Report all errors except E_NOTICE
error_reporting(E_ALL & ~E_NOTICE);

// Report all PHP errors (see changelog)

// Report all PHP errors

// Same as error_reporting(E_ALL);
ini_set('error_reporting', E_ALL);


  • 5.4.0 E_STRICT became part of E_ALL

  • 5.3.0 E_DEPRECATED and E_USER_DEPRECATED introduced.

  • 5.2.0 E_RECOVERABLE_ERROR introduced.

  • 5.0.0 E_STRICT introduced (not part of E_ALL).

What is the best way to test for an empty string with jquery-out-of-the-box?

Since you can also input numbers as well as fixed type strings, the answer should actually be:

function isBlank(value) {
  return $.trim(value);

List of lists into numpy array

Just use pandas


this only works for a list of lists

if you have a list of list of lists you might want to try something along the lines of


ImportError: No module named apiclient.discovery

I had the same problem because of a bug in the installation of the URITemplate module.

This solved the problem:

pip install --force-reinstall

How to calculate the CPU usage of a process by PID in Linux from C?

When you want monitor specified process, usually it is done by scripting. Here is perl example. This put percents as the same way as top, scalling it to one CPU. Then when some process is active working with 2 threads, cpu usage can be more than 100%. Specially look how cpu cores are counted :D then let me show my example:


my $pid=1234; #insert here monitored process PID

#returns current process time counters or single undef if unavailable
#returns:  1. process counter  , 2. system counter , 3. total system cpu cores
sub GetCurrentLoads {
    my $pid=shift;
    my $fh;
    my $line;
    open $fh,'<',"/proc/$pid/stat" or return undef;
    close $fh;
    return undef unless $line=~/^\d+ \([^)]+\) \S \d+ \d+ \d+ \d+ -?\d+ \d+ \d+ \d+ \d+ \d+ (\d+) (\d+)/;
    my $TimeApp=$1+$2;
    my $TimeSystem=0;
    my $CpuCount=0;
    open $fh,'<',"/proc/stat" or return undef;
    while (defined($line=<$fh>)) {
        if ($line=~/^cpu\s/) {
            foreach my $nr ($line=~/\d+/g) { $TimeSystem+=$nr; };
        $CpuCount++ if $line=~/^cpu\d/;
    close $fh;
    return undef if $TimeSystem==0;
    return $TimeApp,$TimeSystem,$CpuCount;

my ($currApp,$currSys,$lastApp,$lastSys,$cores);
while () {
    printf "Load is: %5.1f\%\n",($currApp-$lastApp)/($currSys-$lastSys)*$cores*100 if defined $currApp and defined $lastApp and defined $currSys and defined $lastSys;
    sleep 1;

I hope it will help you in any monitoring. Of course you should use scanf or other C functions for converting any perl regexpes I've used to C source. Of course 1 second for sleeping is not mandatory. you can use any time. effect is, you will get averrage load on specfied time period. When you will use it for monitoring, of course last values you should put outside. It is needed, because monitoring usually calls scripts periodically, and script should finish his work asap.

How to access the correct `this` inside a callback?

Another approach, which is the standard way since DOM2 to bind this within the event listener, that let you always remove the listener (among other benefits), is the handleEvent(evt)method from the EventListener interface:

var obj = {
  handleEvent(e) {
    // always true
    console.log(this === obj);

document.body.addEventListener('click', obj);

Detailed information about using handleEvent can be found here:

Detect when an HTML5 video finishes

Here is a simple approach which triggers when the video ends.


    <video id="myVideo" controls="controls">
        <source src="video.mp4" type="video/mp4">
        etc ...

<script type='text/javascript'>

    document.getElementById('myVideo').addEventListener('ended', function(e) {

        alert('The End');



In the 'EventListener' line substitute the word 'ended' with 'pause' or 'play' to capture those events as well.

How to get Time from DateTime format in SQL?

Assuming Sql server


IE8 crashes when loading website - res://ieframe.dll/acr_error.htm

To prevent IE8 from going on an endless loop of refreshing and crashing it stops after two times and shows this url. There could be many issues that might be causing it to crash.

In my case an upgrade to jQuery v1.10.2 from v1.4.4 causing the issue, but it must have been mostly our code bad and was now more evident with the upgrade.

My observation was everything seems working fine on IE7/XP, IE8/Win7, IE9/Win7 and IE10/Win7 but was not working fine on IE8/XP and IE8/Server2003. The version of IE8 on Win7 and XP/Server 2003 are different. Here is the list of versions for each Operating System (

Then looked at Event viewer on Win Server 2003 and it had something like faulting module mshtml.dll, version 8.0.6001.18975 and on Win XP it was faulting module mshtml.dll, version 8.0.6001.18702 even though the browser version is same on both which is 8.0.6001.18702.

Then further searching about this mshtml.dll, it looks like Microsoft keeps updating mshtml.dll which is the HTML component of the browser through patches. So then I realised its not the browser version that is important but mshtml.dll version instead.

So I went ahead and downloaded the latest Cumulative patch for IE8 from here ( which updated my mshtml.dll file (in system32 folder) to 8.0.6001.23515 and it started working fine , may be they fixed it some time back probably in this (

See also:

But first things first always reset your browser so that you disable all plugins and rule out the possible cause by external plugins.

Is there any sed like utility for cmd.exe?

> (Get-content file.txt) | Foreach-Object {$_ -replace "^SourceRegexp$", "DestinationString"} | Set-Content file.txt

This is behaviour of

sed -i 's/^SourceRegexp$/DestinationString/g' file.txt

Getting rid of \n when using .readlines()

I recently used this to read all the lines from a file:

alist = open('maze.txt').read().split()

or you can use this for that little bit of extra added safety:

with f as open('maze.txt'):
    alist =

It doesn't work with whitespace in-between text in a single line, but it looks like your example file might not have whitespace splitting the values. It is a simple solution and it returns an accurate list of values, and does not add an empty string: '' for every empty line, such as a newline at the end of the file.

In, how to get the column names from a datatable

You can loop through the columns collection of the datatable.


Dim dt As New DataTable()
For Each column As DataColumn In dt.Columns


DataTable dt = new DataTable();
foreach (DataColumn column in dt.Columns)

Hope this helps!

How to solve java.lang.NoClassDefFoundError?

It happens a lot with my genymotion devices. Make sure you have a good amount of memory available on your drive where Genymotion is installed.

to_string is not a member of std, says g++ (mingw)

to_string() is only present in c++11 so if c++ version is less use some alternate methods such as sprintf or ostringstream

Organizing a multiple-file Go project

Keep the files in the same directory and use package main in all files.


Then run:

~/myproj/your-program$ go build && ./your-program

What is the difference between <%, <%=, <%# and -%> in ERB in Rails?

I've added the <%% literal tag delimiter as an answer to this because of its obscurity. This will tell erb not to interpret the <% part of the tag which is necessary for js apps like displaying chart.js tooltips etc.

Update (Fixed broken link)

Everything about ERB can now be found here:

Conda environments not showing up in Jupyter Notebook

The nb_conda_kernels package is the best way to use jupyter with conda. With minimal dependencies and configuration, it allows you to use other conda environments from a jupyter notebook running in a different environment. Quoting its documentation:


This package is designed to be managed solely using conda. It should be installed in the environment from which you run Jupyter Notebook or JupyterLab. This might be your base conda environment, but it need not be. For instance, if the environment notebook_env contains the notebook package, then you would run

conda install -n notebook_env nb_conda_kernels

Any other environments you wish to access in your notebooks must have an appropriate kernel package installed. For instance, to access a Python environment, it must have the ipykernel package; e.g.

conda install -n python_env ipykernel

To utilize an R environment, it must have the r-irkernel package; e.g.

conda install -n r_env r-irkernel

For other languages, their corresponding kernels must be installed.

Then all you need to do is start the jupyter notebook server:

conda activate notebook_env  # only needed if you are not using the base environment for the server
# conda install jupyter # in case you have not installed it already

enter image description here

Despite the plethora of answers and @merv's efforts to improve them, it still hard to find a good one. I made this one CW, so please vote it to the top or improve it!

What is the correct target for the JAVA_HOME environment variable for a Linux OpenJDK Debian-based distribution?

My correct target has always been to download it from Sun and just install it that way. Then you know exactly what directory everything goes in.

But if you'd prefer to stick with the odd way that Debian installs it, my best guess would be the parent directory just above where the java and javac binaries are located.

(since when you specify it in your path it's $JAVA_HOME/bin) (So in your case it would be ... $JAVA_HOME/share and $JAVA_HOME would be /usr ?)

Eh, that doesn't sound right...

I'm interested to hear the answer to this too!

git stash blunder: git stash pop and ended up with merge conflicts

See man git merge (HOW TO RESOLVE CONFLICTS):

After seeing a conflict, you can do two things:

  • Decide not to merge. The only clean-ups you need are to reset the index file to the HEAD commit to reverse 2. and to clean up working tree changes made by 2. and 3.; git-reset --hard can be used for this.

  • Resolve the conflicts. Git will mark the conflicts in the working tree. Edit the files into shape and git add them to the index. Use git commit to seal the deal.

And under TRUE MERGE (to see what 2. and 3. refers to):

When it is not obvious how to reconcile the changes, the following happens:

  1. The HEAD pointer stays the same.

  2. The MERGE_HEAD ref is set to point to the other branch head.

  3. Paths that merged cleanly are updated both in the index file and in your working tree.

  4. ...

So: use git reset --hard if you want to remove the stash changes from your working tree, or git reset if you want to just clean up the index and leave the conflicts in your working tree to merge by hand.

Under man git stash (OPTIONS, pop) you can read in addition:

Applying the state can fail with conflicts; in this case, it is not removed from the stash list. You need to resolve the conflicts by hand and call git stash drop manually afterwards.

input[type='text'] CSS selector does not apply to default-type text inputs?

To be compliant with all browsers you should always declare the input type.

Some browsers will assume default type as 'text', but this isn't a good practice.

How to use ng-if to test if a variable is defined

Try this:


How do I perform HTML decoding/encoding using Python/Django?

Searching the simplest solution of this question in Django and Python I found you can use builtin theirs functions to escape/unescape html code.


I saved your html code in scraped_html and clean_html:

scraped_html = (
    '&lt;img class=&quot;size-medium wp-image-113&quot; '
    'style=&quot;margin-left: 15px;&quot; title=&quot;su1&quot; '
    'src=&quot;; '
    'alt=&quot;&quot; width=&quot;300&quot; height=&quot;194&quot; /&gt;'
clean_html = (
    '<img class="size-medium wp-image-113" style="margin-left: 15px;" '
    'title="su1" src="" '
    'alt="" width="300" height="194" />'


You need Django >= 1.0


To unescape your scraped html code you can use django.utils.text.unescape_entities which:

Convert all named and numeric character references to the corresponding unicode characters.

>>> from django.utils.text import unescape_entities
>>> clean_html == unescape_entities(scraped_html)


To escape your clean html code you can use django.utils.html.escape which:

Returns the given text with ampersands, quotes and angle brackets encoded for use in HTML.

>>> from django.utils.html import escape
>>> scraped_html == escape(clean_html)


You need Python >= 3.4


To unescape your scraped html code you can use html.unescape which:

Convert all named and numeric character references (e.g. &gt;, &#62;, &x3e;) in the string s to the corresponding unicode characters.

>>> from html import unescape
>>> clean_html == unescape(scraped_html)


To escape your clean html code you can use html.escape which:

Convert the characters &, < and > in string s to HTML-safe sequences.

>>> from html import escape
>>> scraped_html == escape(clean_html)

Latex Multiple Linebreaks

You can use the setspace package which gives you spacing environments, e.g.:

my line of text blah blah blah

new line of text with blank line between

Or use a verbatim environment to control the layout of your code precisely.

Page redirect after certain time PHP

You can use javascript to redirect after some time

setTimeout(function () {
   window.location.href= ''; // the redirect goes here

},5000); // 5 seconds

How do you get the current time of day?

Datetime.TimeOfDay returns a TimeSpan and might be what you are looking for.

PageSpeed Insights 99/100 because of Google Analytics - How can I cache GA?


Add this in your HTML or PHP code:

<?php if (!isset($_SERVER['HTTP_USER_AGENT']) || stripos($_SERVER['HTTP_USER_AGENT'], 'Speed Insights') === false): ?>
    (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),

    ga('create', 'UA-PUT YOUR GOOGLE ANALYTICS ID HERE', 'auto');
    ga('send', 'pageview');
<?php endif; ?>


This works fine with JavaScript:

  if(navigator.userAgent.indexOf("Speed Insights") == -1) {
    (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),

    ga('create', 'UA-<PUT YOUR GOOGLE ANALYTICS ID HERE>', 'auto');
    ga('send', 'pageview');

NiloVelez already said: Obviously, it won't make any real improvement, but if your only concern is getting a 100/100 score this will do it.

How to Disable GUI Button in Java

really that not possible to disable JComponent(s) if output to the GUI is invoked from Listener, in all of cases, all events are inside EDT including setEnabled/setVisible,

JComponent(s) is/are disabled/visible if all Events in EDT ends,

there are there ways

1/ safiest way would be look for GlassPane, which prevents after all MouseEvents (not KeyEvents) best code around is by camickr's

2/ use multithreading with SwingWorker for separate and delay concrete event(s), Action from JComponent -> disable JComponent(s) in GUI -> then required Action, but there (if is possible to adds) you have to identify all actions by using myAction#putProperty("String","String")

3/ put Enabled/Visible to the invokeLater() and all Action from Listener must be wrapped into invokeAndWait()

4/ inside Runnable()#Thread

How do you detect Credit card type based on number?

Here is an example of some boolean functions written in Python that return True if the card is detected as per the function name.

def is_american_express(cc_number):
    """Checks if the card is an american express. If us billing address country code, & is_amex, use vpos
    :param cc_number: unicode card number
    return bool(re.match(r'^3[47][0-9]{13}$', cc_number))

def is_visa(cc_number):
    """Checks if the card is a visa, begins with 4 and 12 or 15 additional digits.
    :param cc_number: unicode card number

    # Standard Visa is 13 or 16, debit can be 19
    if bool(re.match(r'^4', cc_number)) and len(cc_number) in [13, 16, 19]:
        return True

    return False

def is_mastercard(cc_number):
    """Checks if the card is a mastercard. Begins with 51-55 or 2221-2720 and 16 in length.
    :param cc_number: unicode card number
    if len(cc_number) == 16 and cc_number.isdigit():  # Check digit, before cast to int
        return bool(re.match(r'^5[1-5]', cc_number)) or int(cc_number[:4]) in range(2221, 2721)
    return False

def is_discover(cc_number):
    """Checks if the card is discover, re would be too hard to maintain. Not a supported card.
    :param cc_number: unicode card number
    if len(cc_number) == 16:
            # return bool(cc_number[:4] == '6011' or cc_number[:2] == '65' or cc_number[:6] in range(622126, 622926))
            return bool(cc_number[:4] == '6011' or cc_number[:2] == '65' or 622126 <= int(cc_number[:6]) <= 622925)
        except ValueError:
            return False
    return False

def is_jcb(cc_number):
    """Checks if the card is a jcb. Not a supported card.
    :param cc_number: unicode card number
    # return bool(re.match(r'^(?:2131|1800|35\d{3})\d{11}$', cc_number))  # wikipedia
    return bool(re.match(r'^35(2[89]|[3-8][0-9])[0-9]{12}$', cc_number))  # PawelDecowski

def is_diners_club(cc_number):
    """Checks if the card is a diners club. Not a supported card.
    :param cc_number: unicode card number
    return bool(re.match(r'^3(?:0[0-6]|[68][0-9])[0-9]{11}$', cc_number))  # 0-5 = carte blance, 6 = international

def is_laser(cc_number):
    """Checks if the card is laser. Not a supported card.
    :param cc_number: unicode card number
    return bool(re.match(r'^(6304|670[69]|6771)', cc_number))

def is_maestro(cc_number):
    """Checks if the card is maestro. Not a supported card.
    :param cc_number: unicode card number
    possible_lengths = [12, 13, 14, 15, 16, 17, 18, 19]
    return bool(re.match(r'^(50|5[6-9]|6[0-9])', cc_number)) and len(cc_number) in possible_lengths

# Child cards

def is_visa_electron(cc_number):
    """Child of visa. Checks if the card is a visa electron. Not a supported card.
    :param cc_number: unicode card number
    return bool(re.match(r'^(4026|417500|4508|4844|491(3|7))', cc_number)) and len(cc_number) == 16

def is_total_rewards_visa(cc_number):
    """Child of visa. Checks if the card is a Total Rewards Visa. Not a supported card.
    :param cc_number: unicode card number
    return bool(re.match(r'^41277777[0-9]{8}$', cc_number))

def is_diners_club_carte_blanche(cc_number):
    """Child card of diners. Checks if the card is a diners club carte blance. Not a supported card.
    :param cc_number: unicode card number
    return bool(re.match(r'^30[0-5][0-9]{11}$', cc_number))  # github PawelDecowski, jquery-creditcardvalidator

def is_diners_club_carte_international(cc_number):
    """Child card of diners. Checks if the card is a diners club international. Not a supported card.
    :param cc_number: unicode card number
    return bool(re.match(r'^36[0-9]{12}$', cc_number))  # jquery-creditcardvalidator

C++ multiline string literal

Just to elucidate a bit on @emsr's comment in @unwind's answer, if one is not fortunate enough to have a C++11 compiler (say GCC 4.2.1), and one wants to embed the newlines in the string (either char * or class string), one can write something like this:

const char *text =
  "This text is pretty long, but will be\n"
  "concatenated into just a single string.\n"
  "The disadvantage is that you have to quote\n"
  "each part, and newlines must be literal as\n"

Very obvious, true, but @emsr's short comment didn't jump out at me when I read this the first time, so I had to discover this for myself. Hopefully, I've saved someone else a few minutes.

How to send 100,000 emails weekly?

People have recommended MailChimp which is a good vendor for bulk email. If you're looking for a good vendor for transactional email, I might be able to help.

Over the past 6 months, we used four different SMTP vendors with the goal of figuring out which was the best one.

Here's a summary of what we found...


  • Cheapest around
  • No analysis/reporting
  • No tracking for opens/clicks
  • Had slight hesitation on some sends


  • Very cheap, but not as cheap as AuthSMTP
  • Beautiful cpanel but no tracking on opens/clicks
  • Send-level activity tracking so you can open a single email that was sent and look at how it looked and the delivery data.
  • Have to use API. Sending by SMTP was recently introduced but it's buggy. For instance, we noticed that quotes (") in the subject line are stripped.
  • Cannot send any attachment you want. Must be on approved list of file types and under a certain size. (10 MB I think)
  • Requires a set list of from names/addresses.


  • Expensive in relation to the others – more than 10 times in some cases
  • Ugly cpanel but great tracking on opens/clicks with email-level detail
  • Had hesitation, at times, when sending. On two occasions, sends took an hour to be delivered
  • Requires a set list of from name/addresses.


  • Not quite a cheap as AuthSMTP but still very cheap. Many customers can exist on 200 free sends per day.
  • Decent cpanel but no in-depth detail on open/click tracking
  • Lots of API options. Options (open/click tracking, etc) can be custom defined on an email-by-email basis. Inbound (reply) email can be posted to our HTTP end point.
  • Absolutely zero hesitation on sends. Every email sent landed in the inbox almost immediately.
  • Can send from any from name/address.


SendGrid was the best with Postmark coming in second place. We never saw any hesitation in send times with either of those two - in some cases we sent several hundred emails at once - and they both have the best ROI, given a solid featureset.

Dynamic require in RequireJS, getting "Module name has not been loaded yet for context" error?

Answering to myself. From the RequireJS website:

define(['require'], function (require) {
    var namedModule = require('name');

This fails because requirejs needs to be sure to load and execute all dependencies before calling the factory function above. [...] So, either do not pass in the dependency array, or if using the dependency array, list all the dependencies in it.

My solution:

// Modules configuration (modules that will be used as Jade helpers)
define(function () {
    return {
        'moment':   'path/to/moment',
        'filesize': 'path/to/filesize',
        '_':        'path/to/lodash',
        '_s':       'path/to/underscore.string'

The loader:

define(['jade', 'lodash', 'config'], function (Jade, _, Config) {
    var deps;

    // Dynamic require
    require(_.values(Config), function () {
        deps = _.object(_.keys(Config), arguments);

        // Use deps...

Convert string to BigDecimal in java

Spring Framework provides an excellent utils class for achieving this.

Util class : NumberUtils

String to BigDecimal conversion -

NumberUtils.parseNumber("135.00", BigDecimal.class);

SQL - ORDER BY 'datetime' DESC

  1. use single quotes for strings
  2. do NOT put single quotes around table names(use ` instead)
  3. do NOT put single quotes around numbers (you can, but it's harder to read)
  4. do NOT put AND between ORDER BY and LIMIT
  5. do NOT put = between ORDER BY, LIMIT keywords and condition

So you query will look like:

SELECT post_datetime 
FROM post 
WHERE type = 'published' 
ORDER BY post_datetime DESC 

How to get the full path of running process?

using System;
using System.Diagnostics;

class Program
    public static void printAllprocesses()
        Process[] processlist = Process.GetProcesses();

        foreach (Process process in processlist)
                String fileName = process.MainModule.FileName;
                String processName = process.ProcessName;

                Console.WriteLine("processName : {0},  fileName : {1}", processName, fileName);
            }catch(Exception e)
                /* You will get access denied exception for system processes, We are skiping the system processes here */


    static void Main()


C/C++ check if one bit is set in, i.e. int variable

Check if bit N (starting from 0) is set:

temp & (1 << N)

There is no builtin function for this.

In Typescript, How to check if a string is Numeric

The way to convert a string to a number is with Number, not parseFloat.

Number('1234') // 1234
Number('9BX9') // NaN

You can also use the unary plus operator if you like shorthand:

+'1234' // 1234
+'9BX9' // NaN

Be careful when checking against NaN (the operator === and !== don't work as expected with NaN). Use:

 isNaN(+maybeNumber) // returns true if NaN, otherwise false

Simple way to understand Encapsulation and Abstraction

Abstraction- Abstraction in simple words can be said as a way out in which the user is kept away from the complex details or detailed working of some system. You can also assume it as a simple way to solve any problem at the design and interface level.

You can say the only purpose of abstraction is to hide the details that can confuse a user. So for simplification purposes, we can use abstraction. Abstraction is also a concept of object-oriented programming. It hides the actual data and only shows the necessary information. For example, in an ATM machine, you are not aware that how it works internally. Only you are concerned to use the ATM interface. So that can be considered as a type of abstraction process.

Encapsulation- Encapsulation is also part of object-oriented programming. In this, all you have to do is to wrap up the data and code together so that they can work as a single unit. it works at the implementation level. it also improves the application Maintainance.

Encapsulation focuses on the process which will save information. Here you have to protect your data from external use.

Bootstrap 4: responsive sidebar menu to top navbar

If this isn't a good solution for any reason, please let me know. It worked fine for me.

What I did is to hide the Sidebar and then make appear the navbar with breakpoints

@media screen and (max-width: 771px) {
    #fixed-sidebar {
        display: none;
    #navbar-superior {
        display: block !important;

How do I vertically align text in a paragraph?

So personally I'm not sure of the best-method way, but one thing I have found works well for vertical alignment is using Flex, as you can justify it's content!

Let's say you have the following HTML and CSS:

.paragraph { 
      font-weight: light;
      color: gray;
      min-height: 6rem;
      background: lightblue;
<h1 class="heading"> Nice to meet you! </h1>
<p class="paragraph"> This is a paragraph </p>

We end up with a paragraph that isn't vertically centered, now if we use a Flex Column and apply the min height + BG to that we get the following:

.myflexbox {
    min-height: 6rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
    background: lightblue;

.paragraph { 
      font-weight: light;
      color: gray;
<h1 class="heading"> Nice to meet you! </h1>
<div class="myflexbox">
    <p class="paragraph"> This is a paragraph </p>

However, in some situations you can't just wrap the P tag in a div so easily, well using Flexbox on the P tag is perfectly fine even if it's not the nicest practice.

.myflexparagraph {
    min-height: 6rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
    background: lightblue;

.paragraph { 
      font-weight: light;
      color: gray;
<h1 class="heading"> Nice to meet you! </h1>
<p class="paragraph myflexparagraph"> This is a paragraph </p>

I have no clue if this is good or bad but if this helps only one person somewhere that's still one more then naught!

Clean up a fork and restart it from the upstream

The simplest solution would be (using 'upstream' as the remote name referencing the original repo forked):

git remote add upstream /url/to/original/repo
git fetch upstream
git checkout master
git reset --hard upstream/master  
git push origin master --force 

(Similar to this GitHub page, section "What should I do if I’m in a bad situation?")

Be aware that you can lose changes done on the master branch (both locally, because of the reset --hard, and on the remote side, because of the push --force).

An alternative would be, if you want to preserve your commits on master, to replay those commits on top of the current upstream/master.
Replace the reset part by a git rebase upstream/master. You will then still need to force push.
See also "What should I do if I’m in a bad situation?"

A more complete solution, backing up your current work (just in case) is detailed in "Cleanup git master branch and move some commit to new branch".

See also "Pull new updates from original GitHub repository into forked GitHub repository" for illustrating what "upstream" is.


Note: recent GitHub repos do protect the master branch against push --force.
So you will have to un-protect master first (see picture below), and then re-protect it after force-pushing).

enter image description here

Note: on GitHub specifically, there is now (February 2019) a shortcut to delete forked repos for pull requests that have been merged upstream.

Declaration of Methods should be Compatible with Parent Methods in PHP

This message means that there are certain possible method calls which may fail at run-time. Suppose you have

class A { public function foo($a = 1) {;}}
class B extends A { public function foo($a) {;}}
function bar(A $a) {$a->foo();}

The compiler only checks the call $a->foo() against the requirements of A::foo() which requires no parameters. $a may however be an object of class B which requires a parameter and so the call would fail at runtime.

This however can never fail and does not trigger the error

class A { public function foo($a) {;}}
class B extends A { public function foo($a = 1) {;}}
function bar(A $a) {$a->foo();}

So no method may have more required parameters than its parent method.

The same message is also generated when type hints do not match, but in this case PHP is even more restrictive. This gives an error:

class A { public function foo(StdClass $a) {;}}
class B extends A { public function foo($a) {;}}

as does this:

class A { public function foo($a) {;}}
class B extends A { public function foo(StdClass $a) {;}}

That seems more restrictive than it needs to be and I assume is due to internals.

Visibility differences cause a different error, but for the same basic reason. No method can be less visible than its parent method.

Genymotion error at start 'Unable to load virtualbox'

For Windows there are 2 installers. Did you use the bundle containing VirtualBox installer? It is call Windows 32/64 bits (with VirtualBox).

The use of Swift 3 @objc inference in Swift 4 mode is deprecated?

I got rid of this warning by changing the "Swift 3 @objc Inference" build setting of my targets to "Default".

Disable Swift 3 @objc inference in Xcode9

From this article:

Before Swift 4, the compiler made some Swift declarations automatically available to Objective-C. For example, if one subclassed from NSObject, the compiler created Objective-C entry points for all methods in such classes. The mechanism is called @objc inference.

In Swift 4, such automatic @objc inference is deprecated because it is costly to generate all those Objective-C entry points. When "Swift 3 @objc Inference" setting is set to "On", it allows the old code to work. However, it will show deprecation warnings that need to be addressed. It is recommended to "fix" these warnings and switch the setting to "Default", which is the default for new Swift projects.

Please also refer to this Swift proposal for more information.

regex match any whitespace

Your regex should work 'as-is'. Assuming that it is doing what you want it to.

wordA(\s*)wordB(?! wordc)

This means match wordA followed by 0 or more spaces followed by wordB, but do not match if followed by wordc. Note the single space between ?! and wordc which means that wordA wordB wordc will not match, but wordA wordB wordc will.

Here are some example matches and the associated replacement output:

enter image description here

Note that all matches are replaced no matter how many spaces. There are a couple of other points: -

  • (?! wordc) is a negative lookahead, so you wont match lines wordA wordB wordc which is assume is intended (and is why the last line is not matched). Currently you are relying on the space after ?! to match the whitespace. You may want to be more precise and use (?!\swordc). If you want to match against more than one space before wordc you can use (?!\s*wordc) for 0 or more spaces or (?!\s*+wordc) for 1 or more spaces depending on what your intention is. Of course, if you do want to match lines with wordc after wordB then you shouldn't use a negative lookahead.

  • * will match 0 or more spaces so it will match wordAwordB. You may want to consider + if you want at least one space.

  • (\s*) - the brackets indicate a capturing group. Are you capturing the whitespace to a group for a reason? If not you could just remove the brackets, i.e. just use \s.

Update based on comment

Hello the problem is not the expression but the HTML out put   that are not considered as whitespace. it's a Joomla website.

Preserving your original regex you can use:


The only difference is that not the regex matches whitespace OR &nbsp;. I replaced wordc with \swordc since that is more explicit. Note as I have already pointed out that the negative lookahead ?! will not match when wordB is followed by a single whitespace and wordc. If you want to match multiple whitespaces then see my comments above. I also preserved the capture group around the whitespace, if you don't want this then remove the brackets as already described above.

Example matches:

enter image description here

The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32'

You get that error because ASP.NET MVC cannot find an id parameter value to provide for the id parameter of your action method.

You need to either pass that as part of the url, ("/Home/Edit/123"), as a query string parameter ("/Home/Edit?id=123") or as a POSTed parameter (make sure to have something like <input type="hidden" name="id" value="123" /> in your HTML form).

Alternatively, you could make the id parameter be a nullable int (Edit(int? id, User collection) {...}), but if the id were null, you wouldn't know what to edit.

Ordering issue with date values when creating pivot tables

Try creating a new pivot table, and not just refreshing.

I had a case where I forgot to add in a few dates. After adding them in I updated the pivot table range and hit refresh. They appeared at the end of the pivot table, out of order. I then tried to simply create a new pivot table and the dates where all in order.

Centering controls within a form in .NET (Winforms)?

you can put all your controls to panel and then write a code to move your panel to center of your form.

panelMain.Location = 
    new Point(ClientSize.Width / 2 - panelMain.Size.Width / 2, 
              ClientSize.Height / 2 - panelMain.Size.Height / 2);

panelMain.Anchor = AnchorStyles.None;

How to remove a row from JTable?

If you need a simple working solution, try using DefaultTableModel.

If you have created your own table model, that extends AbstractTableModel, then you should also implement removeRow() method. The exact implementation depends on the underlying structure, that you have used to store data.

For example, if you have used Vector, then it may be something like this:

public class SimpleTableModel extends AbstractTableModel {
    private Vector<String> columnNames = new Vector<String>();
    // Each value in the vector is a row; String[] - row data;
    private Vector<String[]> data = new Vector<String[]>();


    public String getValueAt(int row, int col) {
        return data.get(row)[col];


    public void removeRow(int row) {

If you have used List, then it would be very much alike:

// Each item in the list is a row; String[] - row data;
List<String[]> arr = new ArrayList<String[]>();

public void removeRow(int row) {


//Integer - row number; String[] - row data;
HashMap<Integer, String[]> data = new HashMap<Integer, String[]>();

public void removeRow(Integer row) {

And if you are using arrays like this one

String[][] data = { { "a", "b" }, { "c", "d" } };

then you're out of luck, because there is no way to dynamically remove elements from arrays. You may try to use arrays by storing separately some flags notifying which rows are deleted and which are not, or by some other devious way, but I would advise against it... That would introduce unnecessary complexity, and would in fact just be solving a problem by creating another. That's a sure-fire way to end up here. Try one of the above ways to store your table data instead.

For better understanding of how this works, and what to do to make your own model work properly, I strongly advise you to refer to Java Tutorial, DefaultTableModel API and it's source code.

Detect HTTP or HTTPS then force HTTPS in JavaScript

Try this

if (location.protocol !== 'https:') {

location.href = blah adds this redirect to the browser history. If the user hits the back button, they will be redirected back to the the same page. It is better to use location.replace as it doesn't add this redirect to the browser history.

Pass array to mvc Action via AJAX

The answer to use the 'traditional' option is correct. I'm just providing some more background info for this who wish to learn more.

From the jQuery documentation:

As of jQuery 1.8, the $.param() method no longer uses jQuery.ajaxSettings.traditional as its default setting and will default to false.

You can also read more here: and


Is it possible to set async:false to $.getJSON call

In my case, Jay D is right. I have to add this before the call.

    async: false

In my previous code, I have this:

var jsonData= (function() {
    var result;
            result = data;
    return result;

It works find. Then I change to

var jsonData= (function() {
    var result;
    $.getJSON('data.txt', {}, function(data){
      result = data;
    return result;

The alert is undefined.

If I add those three lines, the alert shows the data again.

    async: false
var jsonData= (function() {
    var result;
    $.getJSON('data.txt', {}, function(data){
      result = data;
    return result;

Purge Kafka Topic

Following command can be used to delete all the existing messages in kafka topic:

kafka-delete-records --bootstrap-server <kafka_server:port> --offset-json-file delete.json

The structure of the delete.json file should be following:

{ "partitions": [ { "topic": "foo", "partition": 1, "offset": -1 } ], "version": 1 }

where offset :-1 will delete all the records (This command has been tested with kafka 2.0.1

Redis: Show database size/size for keys

Take a look at this project it outputs some interesting stats about keyspaces based on regexs and prefixes. It uses the DEBUG OBJECT command and scans the db, identifying groups of keys and estimating the percentage of space they're taking up.

Output looks like this:


Key                                                | Memory Usage | Expiry Proportion | Last Access Time                                    
notification_3109439                               | 88.14%       | 0.0%              | 2 minutes                               
user_profile_3897016                               | 11.86%       | 99.98%            | 20 seconds  

Or this this one: which does a full analysis on the entire keyspace by analyzing a dump.rdb file offline. This one works well also. It can give you the avg/min/max size for the entries in your db, and will even do it based on a prefix.

How to Import 1GB .sql file to WAMP/phpmyadmin

The values indicated by Ram Sharma might need to be changed in Wamp alias configuration files instead.

In <wamp_dir>/alias/phpmyadmin.conf, in the <Directory> section:

  php_admin_value upload_max_filesize 1280M
  php_admin_value post_max_size 1280M
  php_admin_value max_execution_time 1800

How to Make Laravel Eloquent "IN" Query?

Here is how you do in Eloquent

$users = User::whereIn('id', array(1, 2, 3))->get();

And if you are using Query builder then :

$users = DB::table('users')->whereIn('id', array(1, 2, 3))->get();

How to use paginator from material angular?

Hey so I stumbled upon this and got it working, here is how:

inside my component.html

<mat-paginator #paginator [pageSize]="pageSize" [pageSizeOptions]="[5, 10, 20]" [showFirstLastButtons]="true" [length]="totalSize"
    [pageIndex]="currentPage" (page)="pageEvent = handlePage($event)">

Inside my component.ts

public array: any;
public displayedColumns = ['', '', '', '', ''];
public dataSource: any;    

public pageSize = 10;
public currentPage = 0;
public totalSize = 0;

@ViewChild(MatPaginator) paginator: MatPaginator;

constructor(private app: AppService) { }

ngOnInit() {

public handlePage(e: any) {
  this.currentPage = e.pageIndex;
  this.pageSize = e.pageSize;

private getArray() {
    .subscribe((response) => {
      this.dataSource = new MatTableDataSource<Element>(response);
      this.dataSource.paginator = this.paginator;
      this.array = response;
      this.totalSize = this.array.length;

private iterator() {
  const end = (this.currentPage + 1) * this.pageSize;
  const start = this.currentPage * this.pageSize;
  const part = this.array.slice(start, end);
  this.dataSource = part;

All the paging work is done from within the iterator method. This method works out the skip and take and assigns that to the dataSource for the Material table.

Mockito : doAnswer Vs thenReturn

doAnswer and thenReturn do the same thing if:

  1. You are using Mock, not Spy
  2. The method you're stubbing is returning a value, not a void method.

Let's mock this BookService

public interface BookService {
    String getAuthor();
    void queryBookTitle(BookServiceCallback callback);

You can stub getAuthor() using doAnswer and thenReturn.

BookService service = mock(BookService.class);
// or..
doAnswer(new Answer() {
    public Object answer(InvocationOnMock invocation) throws Throwable {
        return "Joshua";

Note that when using doAnswer, you can't pass a method on when.

// Will throw UnfinishedStubbingException
doAnswer(invocation -> "Joshua").when(service.getAuthor());

So, when would you use doAnswer instead of thenReturn? I can think of two use cases:

  1. When you want to "stub" void method.

Using doAnswer you can do some additionals actions upon method invocation. For example, trigger a callback on queryBookTitle.

BookServiceCallback callback = new BookServiceCallback() {
    public void onSuccess(String bookTitle) {
        assertEquals("Effective Java", bookTitle);
doAnswer(new Answer() {
    public Object answer(InvocationOnMock invocation) throws Throwable {
        BookServiceCallback callback = (BookServiceCallback) invocation.getArguments()[0];
        callback.onSuccess("Effective Java");
        // return null because queryBookTitle is void
        return null;
  1. When you are using Spy instead of Mock

When using when-thenReturn on Spy Mockito will call real method and then stub your answer. This can cause a problem if you don't want to call real method, like in this sample:

List list = new LinkedList();
List spy = spy(list);
// Will throw java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
assertEquals("java", spy.get(0));

Using doAnswer we can stub it safely.

List list = new LinkedList();
List spy = spy(list);
doAnswer(invocation -> "java").when(spy).get(0);
assertEquals("java", spy.get(0));

Actually, if you don't want to do additional actions upon method invocation, you can just use doReturn.

List list = new LinkedList();
List spy = spy(list);
assertEquals("java", spy.get(0));

Remove an onclick listener

You could add the following extension function:

fun View.removeClickListener() {
  isClickable = false

And then on your callers you'd do:

val textView = findViewById(

Python - Module Not Found

I had same error. For those who run python scripts on different servers, please check if the python path is correctly specified in shebang. For me on each server it was located in different dirs.

MySQL - How to select rows where value is in array?

By the time the query gets to SQL you have to have already expanded the list. The easy way of doing this, if you're using IDs from some internal, trusted data source, where you can be 100% certain they're integers (e.g., if you selected them from your database earlier) is this:

$sql = 'SELECT * WHERE id IN (' . implode(',', $ids) . ')';

If your data are coming from the user, though, you'll need to ensure you're getting only integer values, perhaps most easily like so:

$sql = 'SELECT * WHERE id IN (' . implode(',', array_map('intval', $ids)) . ')';

Boolean checking in the 'if' condition

This is more readable and good practice too.

//do sth
//do sth

Is there a command to undo git init?

Git keeps all of its files in the .git directory. Just remove that one and init again.

This post well show you how to find the hide .git file on Windows, Mac OSX, Ubuntu

Double value to round up in Java

double TotalPrice=90.98989898898;

  DecimalFormat format_2Places = new DecimalFormat("0.00");

    TotalPrice = Double.valueOf(format_2Places.format(TotalPrice));

java.lang.IllegalStateException: Error processing condition on org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration

I know this is quite an old one, but I faced similar issue and resolved it in a different way. The actuator-autoconfigure pom somehow was invalid and so it was throwing IllegalStateException. I removed the actuator* dependencies from my maven repo and did a Maven update in eclipse, which then downloaded the correct/valid dependencies and resolved my issue.

How do I launch a Git Bash window with particular working directory using a script?

This is the command which can be executed directly in Run dialog box (shortcut is win+R) and also works well saved as a .bat script:

cmd /c (start /d "/path/to/dir" bash --login) && exit

Validating IPv4 addresses with regexp

The most precise, straightforward and compact IPv4 regexp I can imagine is


But what about the performance/efficiency of ... Sorry I don't know, who cares?

How to delete large data of table in SQL without log?

Another use:

SET ROWCOUNT 1000 -- Buffer


DELETE LargeTable  WHERE readTime < @DATE
   DELETE LargeTable  WHERE readTime < @DATE


If transaction log is enabled, disable transaction logs.


Convert Dictionary to JSON in Swift

Swift 3:

let jsonData = try? dict, options: [])
let jsonString = String(data: jsonData!, encoding: .utf8)!

How do I install pip on macOS or OS X?

On Mac:

  1. Install easy_install

    curl -o - | sudo python
  2. Install pip

    sudo easy_install pip
  3. Now, you could install external modules. For example

    pip install regex   # This is only an example for installing other modules

NoClassDefFoundError while trying to run my jar with java.exe -jar...what's wrong?

I have found when I am using a manifest that the listing of jars for the classpath need to have a space after the listing of each jar e.g. "required_lib/sun/pop3.jar required_lib/sun/smtp.jar ". Even if it is the last in the list.

Uncaught SyntaxError: Invalid or unexpected token

The accepted answer work when you have a single line string(the email) but if you have a

multiline string, the error will remain.

Please look into this matter:

<!-- start: definition-->
    dynamic item = new System.Dynamic.ExpandoObject();
    item.MultiLineString = @"a multi-line
    item.SingleLineString = "a single-line string";
<!-- end: definition-->
<a href="#" onclick="Getinfo('@item.MultiLineString')">6/16/2016 2:02:29 AM</a>
    function Getinfo(text) {

Change the single-quote(') to backtick(`) in Getinfo as bellow and error will be fixed:

<a href="#" onclick="Getinfo(`@item.MultiLineString`)">6/16/2016 2:02:29 AM</a>

A function to convert null to string

Convert.ToString(object) converts to string. If the object is null, Convert.ToString converts it to an empty string.

Calling .ToString() on an object with a null value throws a System.NullReferenceException.


Two exceptions to the rules:

1) ConvertToString(string) on a null string will always return null.

2) ToString(Nullable<T>) on a null value will return "" .

Code Sample:

// 1) Objects:

object obj = null;

//string valX1 = obj.ToString();           // throws System.NullReferenceException !!!
string val1 = Convert.ToString(obj);    

Console.WriteLine(val1 == ""); // True
Console.WriteLine(val1 == null); // False

// 2) Strings

String str = null;
//string valX2 = str.ToString();    // throws System.NullReferenceException !!!
string val2 = Convert.ToString(str); 

Console.WriteLine(val2 == ""); // False
Console.WriteLine(val2 == null); // True            

// 3) Nullable types:

long? num = null;
string val3 = num.ToString();  // ok, no error

Console.WriteLine(num == null); // True
Console.WriteLine(val3 == "");  // True
Console.WriteLine(val3 == null); // False 

val3 = Convert.ToString(num);  

Console.WriteLine(num == null);  // True
Console.WriteLine(val3 == "");  // True
Console.WriteLine(val3 == null); // False

Extract a page from a pdf as a jpeg

There is no need to install Poppler on your OS. This will work:

pip install Wand

from wand.image import Image

f = "somefile.pdf"
with(Image(filename=f, resolution=120)) as source: 
    for i, image in enumerate(source.sequence):
        newfilename = f[:-4] + str(i + 1) + '.jpeg'

How can I override inline styles with external CSS?

<div style="background: red;">
    The inline styles for this div should make it red.

div[style] {
   background: yellow !important;

Below is the link for more details:

How to parse JSON in Java

There are many JSON libraries available in Java.

The most notorious ones are: Jackson, GSON, Genson, FastJson and org.json.

There are typically three things one should look at for choosing any library:

  1. Performance
  2. Ease of use (code is simple to write and legible) - that goes with features.
  3. For mobile apps: dependency/jar size

Specifically for JSON libraries (and any serialization/deserialization libs), databinding is also usually of interest as it removes the need of writing boiler-plate code to pack/unpack the data.

For 1, see this benchmark: I did using JMH which compares (jackson, gson, genson, fastjson, org.json, jsonp) performance of serializers and deserializers using stream and databind APIs. For 2, you can find numerous examples on the Internet. The benchmark above can also be used as a source of examples...

Quick takeaway of the benchmark: Jackson performs 5 to 6 times better than org.json and more than twice better than GSON.

For your particular example, the following code decodes your json with jackson:

public class MyObj {

    private PageInfo pageInfo;
    private List<Post> posts;

    static final class PageInfo {
        private String pageName;
        private String pagePic;

    static final class Post {
        private String post_id;
        private String actorId;
        private String pictureOfPoster;
        private String nameOfPoster;
        private String likesCount;
        private List<String> comments;
        private String timeOfPost;

    private static final ObjectMapper JACKSON = new ObjectMapper();
    public static void main(String[] args) throws IOException {
        MyObj o = JACKSON.readValue(args[0], MyObj.class); // assumes args[0] contains your json payload provided in your question.

Let me know if you have any questions.

Why doesn't margin:auto center an image?

I have found... margin: 0 auto; works for me. But I have also seen it NOT work due to the class being trumped by another specificity that had ... float:left; so watch for that you may need to add ... float:none; this worked in my case as I was coding a media query.

How can I disable ReSharper in Visual Studio and enable it again?

Very simple steps:

  1. Go to Extensions ? Manage Extensions
  2. Click on Installed section at the top left and search for "resharper"

You will see disable button over the extension, click to it then restart Visual Studio and that's it!

enter image description here

Convert string to nullable type (int, double, etc...)

public static class GenericExtension
    public static T? ConvertToNullable<T>(this String s) where T : struct 
            return (T?)TypeDescriptor.GetConverter(typeof(T)).ConvertFrom(s);
        catch (Exception)
            return null;

Include php files when they are in different folders

None of the above answers fixed this issue for me. I did it as following (Laravel with Ubuntu server):

     $footerFile = '/var/www/website/main/resources/views/emails/elements/emailfooter.blade.php';

VBA Public Array : how to?

This worked for me, seems to work as global :

Dim savePos(2 To 8) As Integer

And can call it from every sub, for example getting first element :

MsgBox (savePos(2))

How can I create basic timestamps or dates? (Python 3.4)

>>> import time
>>> print(time.strftime('%a %H:%M:%S'))
Mon 06:23:14

WebAPI to Return XML

If you don't want the controller to decide the return object type, you should set your method return type as System.Net.Http.HttpResponseMessage and use the below code to return the XML.

public HttpResponseMessage Authenticate()
  //process the request 

  string XML="<note><body>Message content</body></note>";
  return new HttpResponseMessage() 
    Content = new StringContent(XML, Encoding.UTF8, "application/xml") 

This is the quickest way to always return XML from Web API.

:first-child not working as expected

The h1:first-child selector means

Select the first child of its parent
if and only if it's an h1 element.

The :first-child of the container here is the ul, and as such cannot satisfy h1:first-child.

There is CSS3's :first-of-type for your case:

.detail_container h1:first-of-type
    color: blue;

But with browser compatibility woes and whatnot, you're better off giving the first h1 a class, then targeting that class:

.detail_container h1.first
    color: blue;

What is meant with "const" at end of function declaration?

Similar to this question.

In essence it means that the method Bar will not modify non mutable member variables of Foo.

' << ' operator in verilog

<< is the left-shift operator, as it is in many other languages.

Here RAM_DEPTH will be 1 left-shifted by 8 bits, which is equivalent to 2^8, or 256.

How does one convert a grayscale image to RGB in OpenCV (Python)?

One you convert your image to gray-scale you cannot got back. You have gone from three channel to one, when you try to go back all three numbers will be the same. So the short answer is no you cannot go back. The reason your backtorgb function this throwing that error is because it needs to be in the format:

CvtColor(input, output, CV_GRAY2BGR)

OpenCV use BGR not RGB, so if you fix the ordering it should work, though your image will still be gray.

Detecting iOS orientation change instantly

Why you didn`t use

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation


Or you can use this

-(void) willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration

Or this

-(void) didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation

Hope it owl be useful )

Get Filename Without Extension in Python

No need for regex. os.path.splitext is your friend:

>>> ('1.1.1', '.jpg')

Fatal Error :1:1: Content is not allowed in prolog

The real solution that I found for this issue was by disabling any XML Format post processors. I have added a post processor called "jp@gc - XML Format Post Processor" and started noticing the error "Fatal Error :1:1: Content is not allowed in prolog"

By disabling the post processor had stopped throwing those errors.

- java.lang.NullPointerException - setText on null object reference

Here lies your problem:

private void fillTextView (int id, String text) {
    TextView tv = (TextView) findViewById(id);
    tv.setText(text); // tv is null

--> (TextView) findViewById(id); // returns null But from your code, I can't find why this method returns null. Try to track down, what id you give as a parameter and if this view with the specified id exists.

The error message is very clear and even tells you at what method. From the documentation:

public final View findViewById (int id)
    Look for a child view with the given id. If this view has the given id, return this view.
        id  The id to search for.
        The view that has the given id in the hierarchy or null

In other words: You have no view with the id you give as a parameter.

Send push to Android by C# using FCM (Firebase Cloud Messaging)

Based on Teste's code .. I can confirm the following works. I can't say whether or not this is "good" code, but it certainly works and could get you back up and running quickly if you ended up with GCM to FCM server problems!

public AndroidFCMPushNotificationStatus SendNotification(string serverApiKey, string senderId, string deviceId, string message)
    AndroidFCMPushNotificationStatus result = new AndroidFCMPushNotificationStatus();

        result.Successful = false;
        result.Error = null;

        var value = message;
        WebRequest tRequest = WebRequest.Create("");
        tRequest.Method = "post";
        tRequest.ContentType = "application/x-www-form-urlencoded;charset=UTF-8";
        tRequest.Headers.Add(string.Format("Authorization: key={0}", serverApiKey));
        tRequest.Headers.Add(string.Format("Sender: id={0}", senderId));

        string postData = "collapse_key=score_update&time_to_live=108&delay_while_idle=1&data.message=" + value + "&data.time=" + System.DateTime.Now.ToString() + "&registration_id=" + deviceId + "";

        Byte[] byteArray = Encoding.UTF8.GetBytes(postData);
        tRequest.ContentLength = byteArray.Length;

        using (Stream dataStream = tRequest.GetRequestStream())
            dataStream.Write(byteArray, 0, byteArray.Length);

            using (WebResponse tResponse = tRequest.GetResponse())
                using (Stream dataStreamResponse = tResponse.GetResponseStream())
                    using (StreamReader tReader = new StreamReader(dataStreamResponse))
                        String sResponseFromServer = tReader.ReadToEnd();
                        result.Response = sResponseFromServer;
    catch (Exception ex)
        result.Successful = false;
        result.Response = null;
        result.Error = ex;

    return result;

public class AndroidFCMPushNotificationStatus
    public bool Successful

    public string Response
    public Exception Error

Unbalanced calls to begin/end appearance transitions for <UITabBarController: 0x197870>

I had the same error. I have a tab bar with 3 items and I was unconsciously trying to call the root view controller of item 1 in the item 2 of my tab bar using performSegueWithIdentifier.

What happens is that it calls the view controller and goes back to the root view controller of item 2 after a few seconds and logs that error.

Apparently, you cannot call the root view controller of an item to another item.

So instead of performSegueWithIdentifier

I used [self.parentViewController.tabBarController setSelectedIndex:0];

Hope this helps someone.

C# : Out of Memory exception

I know this is an old question but since none of the answers mentioned the large object heap, this might be of use to others who find this question ...

Any memory allocation in .NET that is over 85,000 bytes comes from the large object heap (LOH) not the normal small object heap. Why does this matter? Because the large object heap is not compacted. Which means that the large object heap gets fragmented and in my experience this inevitably leads to out of memory errors.

In the original question the list has 50,000 items in it. Internally a list uses an array, and assuming 32 bit that requires 50,000 x 4bytes = 200,000 bytes (or double that if 64 bit). So that memory allocation is coming from the large object heap.

So what can you do about it?

If you are using a .net version prior to 4.5.1 then about all you can do about it is to be aware of the problem and try to avoid it. So, in this instance, instead of having a list of vehicles you could have a list of lists of vehicles, provided no list ever had more than about 18,000 elements in it. That can lead to some ugly code, but it is viable work around.

If you are using .net 4.5.1 or later then the behaviour of the garbage collector has changed subtly. If you add the following line where you are about to make large memory allocations:

System.Runtime.GCSettings.LargeObjectHeapCompactionMode = System.Runtime.GCLargeObjectHeapCompactionMode.CompactOnce;

it will force the garbage collector to compact the large object heap - next time only.

It might not be the best solution but the following has worked for me:

int tries = 0;
while (tries++ < 2)
    . . some large allocation . .
  catch (System.OutOfMemoryException)
    System.Runtime.GCSettings.LargeObjectHeapCompactionMode = System.Runtime.GCLargeObjectHeapCompactionMode.CompactOnce;

of course this only helps if you have the physical (or virtual) memory available.

Setting dynamic scope variables in AngularJs - scope.<some_string>

Just to add into alread given answers, the following worked for me:


<div id="div{{$index+1}}" data-ng-show="val{{$index}}">

Where $index is the loop index.

Javascript (where value is the passed parameter to the function and it will be the value of $index, current loop index):

var variable = "val"+value;
if ($scope[variable] === undefined)
    $scope[variable] = true;
}else {
    $scope[variable] = !$scope[variable];

How to declare a type as nullable in TypeScript?

i had this same question a while back.. all types in ts are nullable, because void is a subtype of all types (unlike, for example, scala).

see if this flowchart helps -

How to apply shell command to each line of a command output?

It's probably easiest to use xargs. In your case:

ls -1 | xargs -L1 echo

The -L flag ensures the input is read properly. From the man page of xargs:

-L number
    Call utility for every number non-empty lines read. 
    A line ending with a space continues to the next non-empty line. [...]

How do I prompt for Yes/No/Cancel input in a Linux shell script?

This solution reads a single character and calls a function on a yes response.

read -p "Are you sure? (y/n) " -n 1
if [[ $REPLY =~ ^[Yy]$ ]]; then

Convert a CERT/PEM certificate to a PFX certificate

Here is how to do this on Windows without third-party tools:

  1. Import certificate to the certificate store. In Windows Explorer select "Install Certificate" in context menu. enter image description here Follow the wizard and accept default options "Local User" and "Automatically".

  2. Find your certificate in certificate store. On Windows 10 run the "Manage User Certificates" MMC. On Windows 2013 the MMC is called "Certificates". On Windows 10 by default your certificate should be under "Personal"->"Certificates" node.

  3. Export Certificate. In context menu select "Export..." menu: enter image description here

    Select "Yes, export the private key": enter image description here

    You will see that .PFX option is enabled in this case: enter image description here

    Specify password for private key.

How to make layout with rounded corners..?

1: Define layout_bg.xml in drawables:

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="">
    <solid android:color="#FFFFFF"/>
    <stroke android:width="3dp" android:color="#B1BCBE" />
    <corners android:radius="10dp"/>
    <padding android:left="0dp" android:top="0dp" android:right="0dp" android:bottom="0dp" />

2: Add layout_bg.xml as background to your layout


Get the first element of an array

You can get the first element by using this coding:

$array_key_set = array_keys($array);
$first_element = $array[$array_key_set[0]];

Or use:

foreach($array as $arr)
echo $first_element;

How to test code dependent on environment variables using JUnit?

I use System.getEnv() to get the map and I keep as a field, so I can mock it:

public class AAA {

    Map<String, String> environmentVars; 

    public String readEnvironmentVar(String varName) {
        if (environmentVars==null) environmentVars = System.getenv();   
        return environmentVars.get(varName);

public class AAATest {

         public void test() {
              aaa.environmentVars = new HashMap<String,String>();
              aaa.environmentVars.put("NAME", "value");

How to render a PDF file in Android

I have made a hybrid approach from some of the answers given to this and other similar posts:

This solution checks if a PDF reader app is installed and does the following: - If a reader is installed, download the PDF file to the device and start a PDF reader app - If no reader is installed, ask the user if he wants to view the PDF file online through Google Drive

NOTE! This solution uses the Android DownloadManager class, which was introduced in API9 (Android 2.3 or Gingerbread). This means that it doesn't work on Android 2.2 or earlier.

I wrote a blog post about it here, but I've provided the full code below for completeness:

public class PDFTools {
    private static final String GOOGLE_DRIVE_PDF_READER_PREFIX = "";
    private static final String PDF_MIME_TYPE = "application/pdf";
    private static final String HTML_MIME_TYPE = "text/html";

     * If a PDF reader is installed, download the PDF file and open it in a reader. 
     * Otherwise ask the user if he/she wants to view it in the Google Drive online PDF reader.<br />
     * <br />
     * <b>BEWARE:</b> This method
     * @param context
     * @param pdfUrl
     * @return
    public static void showPDFUrl( final Context context, final String pdfUrl ) {
        if ( isPDFSupported( context ) ) {
            downloadAndOpenPDF(context, pdfUrl);
        } else {
            askToOpenPDFThroughGoogleDrive( context, pdfUrl );

     * Downloads a PDF with the Android DownloadManager and opens it with an installed PDF reader app.
     * @param context
     * @param pdfUrl
    public static void downloadAndOpenPDF(final Context context, final String pdfUrl) {
        // Get filename
        final String filename = pdfUrl.substring( pdfUrl.lastIndexOf( "/" ) + 1 );
        // The place where the downloaded PDF file will be put
        final File tempFile = new File( context.getExternalFilesDir( Environment.DIRECTORY_DOWNLOADS ), filename );
        if ( tempFile.exists() ) {
            // If we have downloaded the file before, just go ahead and show it.
            openPDF( context, Uri.fromFile( tempFile ) );

        // Show progress dialog while downloading
        final ProgressDialog progress = context, context.getString( R.string.pdf_show_local_progress_title ), context.getString( R.string.pdf_show_local_progress_content ), true );

        // Create the download request
        DownloadManager.Request r = new DownloadManager.Request( Uri.parse( pdfUrl ) );
        r.setDestinationInExternalFilesDir( context, Environment.DIRECTORY_DOWNLOADS, filename );
        final DownloadManager dm = (DownloadManager) context.getSystemService( Context.DOWNLOAD_SERVICE );
        BroadcastReceiver onComplete = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                if ( !progress.isShowing() ) {
                context.unregisterReceiver( this );

                long downloadId = intent.getLongExtra( DownloadManager.EXTRA_DOWNLOAD_ID, -1 );
                Cursor c = dm.query( new DownloadManager.Query().setFilterById( downloadId ) );

                if ( c.moveToFirst() ) {
                    int status = c.getInt( c.getColumnIndex( DownloadManager.COLUMN_STATUS ) );
                    if ( status == DownloadManager.STATUS_SUCCESSFUL ) {
                        openPDF( context, Uri.fromFile( tempFile ) );
        context.registerReceiver( onComplete, new IntentFilter( DownloadManager.ACTION_DOWNLOAD_COMPLETE ) );

        // Enqueue the request
        dm.enqueue( r );

     * Show a dialog asking the user if he wants to open the PDF through Google Drive
     * @param context
     * @param pdfUrl
    public static void askToOpenPDFThroughGoogleDrive( final Context context, final String pdfUrl ) {
        new AlertDialog.Builder( context )
            .setTitle( R.string.pdf_show_online_dialog_title )
            .setMessage( R.string.pdf_show_online_dialog_question )
            .setNegativeButton( R.string.pdf_show_online_dialog_button_no, null )
            .setPositiveButton( R.string.pdf_show_online_dialog_button_yes, new OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    openPDFThroughGoogleDrive(context, pdfUrl); 

     * Launches a browser to view the PDF through Google Drive
     * @param context
     * @param pdfUrl
    public static void openPDFThroughGoogleDrive(final Context context, final String pdfUrl) {
        Intent i = new Intent( Intent.ACTION_VIEW );
        i.setDataAndType(Uri.parse(GOOGLE_DRIVE_PDF_READER_PREFIX + pdfUrl ), HTML_MIME_TYPE );
        context.startActivity( i );
     * Open a local PDF file with an installed reader
     * @param context
     * @param localUri
    public static final void openPDF(Context context, Uri localUri ) {
        Intent i = new Intent( Intent.ACTION_VIEW );
        i.setDataAndType( localUri, PDF_MIME_TYPE );
        context.startActivity( i );
     * Checks if any apps are installed that supports reading of PDF files.
     * @param context
     * @return
    public static boolean isPDFSupported( Context context ) {
        Intent i = new Intent( Intent.ACTION_VIEW );
        final File tempFile = new File( context.getExternalFilesDir( Environment.DIRECTORY_DOWNLOADS ), "test.pdf" );
        i.setDataAndType( Uri.fromFile( tempFile ), PDF_MIME_TYPE );
        return context.getPackageManager().queryIntentActivities( i, PackageManager.MATCH_DEFAULT_ONLY ).size() > 0;


Failed to load AppCompat ActionBar with unknown error in android studio

Use this one:

implementation ''
implementation ''

instead of

implementation ''
implementation ''

In my case it removed the rendering problem.

When to use StringBuilder in Java

If you use String concatenation in a loop, something like this,

String s = "";
for (int i = 0; i < 100; i++) {
    s += ", " + i;

then you should use a StringBuilder (not StringBuffer) instead of a String, because it is much faster and consumes less memory.

If you have a single statement,

String s = "1, " + "2, " + "3, " + "4, " ...;

then you can use Strings, because the compiler will use StringBuilder automatically.

IntelliJ, can't start simple web application: Unable to ping server at localhost:1099

I added my hostname to /etc/hosts on localhost. Added JAVA_HOME but still it showed the same error. In the console, there was output:

Unable to start as CATALINA_BASE contains a colon (:) character

I solved the problem by going to Edit configurations -> Startup/Connection -> changing CATALINA_BASE value to the tomcat installation folder. Before that, it was

CATALINA_BASE:   C:\Program Files\Apache Software Foundation\Tomcat 8.0

which can't be correct on a linux machine ;)

How to put scroll bar only for modal-body?

In latest bootstrap version there is a class to make modal body scrollable.

.modal-dialog-scrollable to .modal-dialog.

Bootstrap modal link for modal body scrollable content

<!-- Scrollable modal -->
<div class="modal-dialog modal-dialog-scrollable">

Yahoo Finance API

Here's a simple scraper I created in c# to get streaming quote data printed out to a console. It should be easily converted to java. Based on the following post:

Not too fancy (i.e. no regex etc), just a fast & dirty solution.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Web.Script.Serialization;

namespace WebDataAddin
    public class YahooConstants
        public const string AskPrice = "a00";
        public const string BidPrice = "b00";
        public const string DayRangeLow = "g00";
        public const string DayRangeHigh = "h00";
        public const string MarketCap = "j10";
        public const string Volume = "v00";
        public const string AskSize = "a50";
        public const string BidSize = "b60";
        public const string EcnBid = "b30";
        public const string EcnBidSize = "o50";
        public const string EcnExtHrBid = "z03";
        public const string EcnExtHrBidSize = "z04";
        public const string EcnAsk = "b20";
        public const string EcnAskSize = "o40";
        public const string EcnExtHrAsk = "z05";
        public const string EcnExtHrAskSize = "z07";
        public const string EcnDayHigh = "h01";
        public const string EcnDayLow = "g01";
        public const string EcnExtHrDayHigh = "h02";
        public const string EcnExtHrDayLow = "g11";
        public const string LastTradeTimeUnixEpochformat = "t10";
        public const string EcnQuoteLastTime = "t50";
        public const string EcnExtHourTime = "t51";
        public const string RtQuoteLastTime = "t53";
        public const string RtExtHourQuoteLastTime = "t54";
        public const string LastTrade = "l10";
        public const string EcnQuoteLastValue = "l90";
        public const string EcnExtHourPrice = "l91";
        public const string RtQuoteLastValue = "l84";
        public const string RtExtHourQuoteLastValue = "l86";
        public const string QuoteChangeAbsolute = "c10";
        public const string EcnQuoteAfterHourChangeAbsolute = "c81";
        public const string EcnQuoteChangeAbsolute = "c60";
        public const string EcnExtHourChange1 = "z02";
        public const string EcnExtHourChange2 = "z08";
        public const string RtQuoteChangeAbsolute = "c63";
        public const string RtExtHourQuoteAfterHourChangeAbsolute = "c85";
        public const string RtExtHourQuoteChangeAbsolute = "c64";
        public const string QuoteChangePercent = "p20";
        public const string EcnQuoteAfterHourChangePercent = "c82";
        public const string EcnQuoteChangePercent = "p40";
        public const string EcnExtHourPercentChange1 = "p41";
        public const string EcnExtHourPercentChange2 = "z09";
        public const string RtQuoteChangePercent = "p43";
        public const string RtExtHourQuoteAfterHourChangePercent = "c86";
        public const string RtExtHourQuoteChangePercent = "p44";

        public static readonly IDictionary<string, string> CodeMap = typeof(YahooConstants).GetFields().
            Where(field => field.FieldType == typeof(string)).
            ToDictionary(field => ((string)field.GetValue(null)).ToUpper(), field => field.Name);

    public static class StringBuilderExtensions
        public static bool HasPrefix(this StringBuilder builder, string prefix)
            return ContainsAtIndex(builder, prefix, 0);

        public static bool HasSuffix(this StringBuilder builder, string suffix)
            return ContainsAtIndex(builder, suffix, builder.Length - suffix.Length);

        private static bool ContainsAtIndex(this StringBuilder builder, string str, int index)
            if (builder != null && !string.IsNullOrEmpty(str) && index >= 0
                && builder.Length >= str.Length + index)
                return !str.Where((t, i) => builder[index + i] != t).Any();
            return false;

    public class WebDataAddin
        public const string ScriptStart = "<script>";
        public const string ScriptEnd = "</script>";

        public const string MessageStart = "try{parent.yfs_";
        public const string MessageEnd = ");}catch(e){}";

        public const string DataMessage = "u1f(";
        public const string InfoMessage = "mktmcb(";

        protected static T ParseJson<T>(string json)
            // parse json - max acceptable value retrieved from 
            var deserializer = new JavaScriptSerializer { MaxJsonLength = 2147483647 };
            return deserializer.Deserialize<T>(json);

        public static void Main()
            const string symbols = "GBPUSD=X,SPY,MSFT,BAC,QQQ,GOOG";
            // these are constants in the YahooConstants enum above
            const string attrs = "b00,b60,a00,a50";
            const string url = "{0}&k={1}&r=0&callback=parent.yfs_u1f&mktmcb=parent.yfs_mktmcb&gencallback=parent.yfs_gencb&region=US&lang=en-US&localize=0&mu=1";

            var req = WebRequest.Create(string.Format(url, symbols, attrs));
            req.Proxy.Credentials = CredentialCache.DefaultCredentials;
            var missingCodes = new HashSet<string>();
            var response = req.GetResponse();
            if(response != null)
                var stream = response.GetResponseStream();
                if (stream != null)
                    using (var reader = new StreamReader(stream))
                        var builder = new StringBuilder();
                        var initialPayloadReceived = false;
                        while (!reader.EndOfStream)
                            var c = (char)reader.Read();
                                if (builder.HasSuffix(ScriptStart))
                                    // chop off the first part, and re-append the
                                    // script tag (this is all we care about)
                                    initialPayloadReceived = true;
                                // check if we have a fully formed message
                                // (check suffix first to avoid re-checking 
                                // the prefix over and over)
                                if (builder.HasSuffix(ScriptEnd) &&
                                    var chop = ScriptStart.Length + MessageStart.Length;
                                    var javascript = builder.ToString(chop,
                                        builder.Length - ScriptEnd.Length - MessageEnd.Length - chop);

                                    if (javascript.StartsWith(DataMessage))
                                        var json = ParseJson<Dictionary<string, object>>(

                                        // parse out the data. key should be the symbol

                                        foreach(var symbol in json)
                                            Console.WriteLine("Symbol: {0}", symbol.Key);
                                            var symbolData = (Dictionary<string, object>) symbol.Value;
                                            foreach(var dataAttr in symbolData)
                                                var codeKey = dataAttr.Key.ToUpper();
                                                if (YahooConstants.CodeMap.ContainsKey(codeKey))
                                                    Console.WriteLine("\t{0}: {1}", YahooConstants.
                                                        CodeMap[codeKey], dataAttr.Value);
                                                } else
                                                    Console.WriteLine("\t{0}: {1} (Warning! No Code Mapping Found)", 
                                                        codeKey, dataAttr.Value);

                                    } else if(javascript.StartsWith(InfoMessage))
                                        var json = ParseJson<Dictionary<string, object>>(

                                        foreach (var dataAttr in json)
                                            Console.WriteLine("\t{0}: {1}", dataAttr.Key, dataAttr.Value);
                                    } else
                                        throw new Exception("Cannot recognize the message type");

How to download Visual Studio 2017 Community Edition for offline installation?

The command above worked for me

C:\Users\marcelo\Downloads\vs_community.exe --lang en-en --layout C:\VisualStudio2017 --all

android pick images from gallery

For only pick from local add this :


And this working nice :

    val i = Intent(Intent.ACTION_GET_CONTENT,MediaStore.Images.Media.EXTERNAL_CONTENT_URI)
    i.type = "image/*"
    startActivityForResult(Intent.createChooser(i,"Select Photo"),pickImageRequestCode)

React - How to pass HTML tags in props?

You can successfully utilize React fragments for this task. Depending on the React version you use, you can use short syntax: <> or the full tag: <React.Fragment>. Works especially well if you don't want to wrap entire string within HTML tags.

<MyComponent text={<>Hello World. <u>Don't be so ruthless</u>.</>} />

Are multiple `.gitignore`s frowned on?

There are many scenarios where you want to commit a directory to your Git repo but without the files in it, for example the logs, cache, uploads directories etc.

So what I always do is to add a .gitignore file in those directories with the following content:


With this .gitignore file, Git will not track any files in those directories yet still allow me to add the .gitignore file and hence the directory itself to the repo.

How do I rename both a Git local and remote branch name?

I had to do the following task to rename local and remote branch:

# Rename the local branch to the new name
git branch -m <old_name> <new_name>

#  Delete the old remote branch
git push origin --delete <old_name>

# push to new remote branch - creates new remote branch
git push origin <new_name>

# set new remote branch as default remote branch for local branch
git branch --set-upstream-to=origin/<new_name> <new_name>

Can Selenium WebDriver open browser windows silently in the background?

Here is a .NET solution that worked for me:

Download PhantomJS at

Copy the .exe file from the bin folder in the download folder and paste it to the bin debug/release folder of your Visual Studio project.

Add this using

using OpenQA.Selenium.PhantomJS;

In your code, open the driver like this:

PhantomJSDriver driver = new PhantomJSDriver();
using (driver)
   // Your code here

Best equivalent VisualStudio IDE for Mac to program .NET/C#

Whilst more of a workaround, if you're running an Intel Mac, you could go the virtualisation route - at least then you can run the same tools.

Send mail via Gmail with PowerShell V2's Send-MailMessage

I agree with Christian Muggli's solution, although at first I still got the error that Scott Weinstein reported. How you get past that is:

EITHER first login to Gmail from the machine this will run on, using the account specified. (It is not necessary to add any Google sites to the Trusted Sites zone, even if Internet Explorer Enhanced Security Configuration is enabled.)

OR, on your first attempt, you will get the error, and your Gmail account will get a notice about suspicious login, so follow their instructions to allow future logins from the machine this will run on.

How do you get the "object reference" of an object in java when toString() and hashCode() have been overridden?

This is how I solved it:


How to connect to a remote Windows machine to execute commands using python?

Many answers already, but one more option


It's a python clone of the famous psexec. Works without any installation on the remote windows machine.

How do I remove packages installed with Python's easy_install?


$ easy_install -m [PACKAGE]


$ rm -rf .../python2.X/site-packages/[PACKAGE].egg

How to retrieve value from elements in array using jQuery?

Your syntax is incorrect.

card_value = $(array[i]).val(); or card_value = array[i].value;

array[i] is not a jQuery object (for some reason).

Checking your browser's console can be helpful for things like this.

Generic htaccess redirect www to non-www

Hi you can use following rules on your htaccess file:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^
RewriteRule (.*)$1 [R=301,L]

mysql data directory location

If you install MySQL via homebrew on MacOS, you might need to delete your old data directory /usr/local/var/mysql. Otherwise, it will fail during the initialization process with the following error:

==> /usr/local/Cellar/mysql/8.0.16/bin/mysqld --initialize-insecure --user=hohoho --basedir=/usr/local/Cellar/mysql/8.0.16 --datadir=/usr/local/var/mysql --tmpdir=/tmp
2019-07-17T16:30:51.828887Z 0 [System] [MY-013169] [Server] /usr/local/Cellar/mysql/8.0.16/bin/mysqld (mysqld 8.0.16) initializing of server in progress as process 93487
2019-07-17T16:30:51.830375Z 0 [ERROR] [MY-010457] [Server] --initialize specified but the data directory has files in it. Aborting.
2019-07-17T16:30:51.830381Z 0 [ERROR] [MY-013236] [Server] Newly created data directory /usr/local/var/mysql/ is unusable. You can safely remove it.
2019-07-17T16:30:51.830410Z 0 [ERROR] [MY-010119] [Server] Aborting
2019-07-17T16:30:51.830540Z 0 [System] [MY-010910] [Server] /usr/local/Cellar/mysql/8.0.16/bin/mysqld: Shutdown complete (mysqld 8.0.16)  Homebrew.

How to insert array of data into mysql using php

I would avoid to do a query for each entry.


    $sql = "INSERT INTO email_list (R_ID, EMAIL, NAME) values ";

    $valuesArr = array();
    foreach($EMailArr as $row){

        $R_ID = (int) $row['R_ID'];
        $email = mysql_real_escape_string( $row['email'] );
        $name = mysql_real_escape_string( $row['name'] );

        $valuesArr[] = "('$R_ID', '$email', '$name')";

    $sql .= implode(',', $valuesArr);

    mysql_query($sql) or exit(mysql_error()); 

Docker "ERROR: could not find an available, non-overlapping IPv4 address pool among the defaults to assign to the network"

I had the same error, but in my case, it was because I had too many containers running (about 220).

On npm install: Unhandled rejection Error: EACCES: permission denied

sudo chown -R $(whoami) ~/.npm

sudo chown -R $(whoami) ~/.config

PHP: Read Specific Line From File

omg I'm lacking 7 rep to make comments. This is @Raptor's & @Tomm's comment, since this question still shows up way high in google serps.

He's exactly right. For small files file($file); is perfectly fine. For large files it's total overkill b/c php arrays eat memory like crazy.

I just ran a tiny test with a *.csv with a file size of ~67mb (1,000,000 lines):

$t = -microtime(1);
$file = '../data/1000k.csv';
$lines = file($file);
echo $lines[999999]
//Process finished with exit code 0

And since noone mentioned it yet, I gave the SplFileObject a try, which I actually just recently discovered for myself.

$t = -microtime(1);
$file = '../data/1000k.csv';
$spl = new SplFileObject($file);
echo $spl->current()
//Process finished with exit code 0

This was on my Win7 desktop so it's not representative for production environment, but still ... quite the difference.

Return empty cell from formula in Excel

What I used was a small hack. I used T(1), which returned an empty cell. T is a function in excel that returns its argument if its a string and an empty cell otherwise. So, what you can do is:


Python Set Comprehension

You can get clean and clear solutions by building the appropriate predicates as helper functions. In other words, use the Python set-builder notation the same way you would write the answer with regular mathematics set-notation.

The whole idea behind set comprehensions is to let us write and reason in code the same way we do mathematics by hand.

With an appropriate predicate in hand, problem 1 simplifies to:

 low_primes = {x for x in range(1, 100) if is_prime(x)}

And problem 2 simplifies to:

 low_prime_pairs = {(x, x+2) for x in range(1,100,2) if is_prime(x) and is_prime(x+2)}

Note how this code is a direct translation of the problem specification, "A Prime Pair is a pair of consecutive odd numbers that are both prime."

P.S. I'm trying to give you the correct problem solving technique without actually giving away the answer to the homework problem.

How to get the parents of a Python class?

If you want all the ancestors rather than just the immediate ones, use inspect.getmro:

import inspect
print inspect.getmro(cls)

Usefully, this gives you all ancestor classes in the "method resolution order" -- i.e. the order in which the ancestors will be checked when resolving a method (or, actually, any other attribute -- methods and other attributes live in the same namespace in Python, after all;-).

I can not find my.cnf on my windows computer

Start->Search->For Files and Folders->All Files and Folders

type "my.cnf" and hit search.

How to copy a file to multiple directories using the gnu cp command

Not using cp per se, but...

This came up for me in the context of copying lots of Gopro footage off of a (slow) SD card to three (slow) USB drives. I wanted to read the data only once, because it took forever. And I wanted it recursive.

$ tar cf - src | tee >( cd dest1 ; tar xf - ) >( cd dest2 ; tar xf - ) | ( cd dest3 ; tar xf - )

(And you can add more of those >() sections if you want more outputs.)

I haven't benchmarked that, but it's definitely a lot faster than cp-in-a-loop (or a bunch of parallel cp invocations).

Return JsonResult from web api without its properties

I had a similar problem (differences being I wanted to return an object that was already converted to a json string and my controller get returns a IHttpActionResult)

Here is how I solved it. First I declared a utility class

public class RawJsonActionResult : IHttpActionResult
    private readonly string _jsonString;

    public RawJsonActionResult(string jsonString)
        _jsonString = jsonString;

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
        var content = new StringContent(_jsonString);
        content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
        var response = new HttpResponseMessage(HttpStatusCode.OK) { Content = content };
        return Task.FromResult(response);

This class can then be used in your controller. Here is a simple example

public IHttpActionResult Get()
    var jsonString = "{\"id\":1,\"name\":\"a small object\" }";
    return new RawJsonActionResult(jsonString);

What is the cleanest way to disable CSS transition effects temporarily?

I would advocate disabling animation as suggested by DaneSoul, but making the switch global:

/*kill the transitions on any descendant elements of .notransition*/
.notransition * { 
  -webkit-transition: none !important; 
  -moz-transition: none !important; 
  -o-transition: none !important; 
  -ms-transition: none !important; 
  transition: none !important; 

.notransition can be then applied to the body element, effectively overriding any transition animation on the page:


How can I set a custom date time format in Oracle SQL Developer?

Goto to Tools > Preferences. In the tree, select Database > NLS. There are three Date/Time formats available: Date, Timestamp and Timestamp TZ. Editing the Date format gives the desired effect.

Like I have said above; this approach has not given me a permanent change.

How to show progress bar while loading, using ajax

I did it like this


html {
    -webkit-transition: background-color 1s;
    transition: background-color 1s;
html, body {
    /* For the loading indicator to be vertically centered ensure */
    /* the html and body elements take up the full viewport */
    min-height: 100%;
html.loading {
    /* Replace #333 with the background-color of your choice */
    /* Replace loading.gif with the loading image of your choice */
    background: #333 url('/Images/loading.gif') no-repeat 50% 50%;

    /* Ensures that the transition only runs in one direction */
    -webkit-transition: background-color 0;
    transition: background-color 0;
body {
    -webkit-transition: opacity 1s ease-in;
    transition: opacity 1s ease-in;
html.loading body {
    /* Make the contents of the body opaque during loading */
    opacity: 0;

    /* Ensures that the transition only runs in one direction */
    -webkit-transition: opacity 0;
    transition: opacity 0;


$(document).ready(function () {
   $(document).ajaxStart(function () {     
    $(document).ajaxStop(function () {        
    $(document).ajaxError(function () {       

How do I select an element with its name attribute in jQuery?


Although you should avoid it and if possible select by ID (e.g. #myId) as this has better performance because it invokes the native getElementById.

How to manually install a pypi module without pip/easy_install?

Even though Sheena's answer does the job, pip doesn't stop just there.

From Sheena's answer:

  1. Download the package
  2. unzip it if it is zipped
  3. cd into the directory containing
  4. If there are any installation instructions contained in documentation contained herein, read and follow the instructions OTHERWISE
  5. type in python install

At the end of this, you'll end up with a .egg file in site-packages. As a user, this shouldn't bother you. You can import and uninstall the package normally. However, if you want to do it the pip way, you can continue the following steps.

In the site-packages directory,

  1. unzip <.egg file>
  2. rename the EGG-INFO directory as <pkg>-<version>.dist-info
  3. Now you'll see a separate directory with the package name, <pkg-directory>
  4. find <pkg-directory> > <pkg>-<version>.dist-info/RECORD
  5. find <pkg>-<version>.dist-info >> <pkg>-<version>.dist-info/RECORD. The >> is to prevent overwrite.

Now, looking at the site-packages directory, you'll never realize you installed without pip. To uninstall, just do the usual pip uninstall <pkg>.

Changing navigation bar color in Swift

If you have customized navigation controller, you can use above code snippet. So in my case, I've used as following code pieces.

Swift 3.0, XCode 8.1 version

navigationController.navigationBar.barTintColor =

Navigation Bar Text:

navigationController.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName:]

It is very helpful talks.

Problem with SMTP authentication in PHP using PHPMailer, with Pear Mail works

Try adding this:

$mail->SMTPAuth   = true;
$mail->SMTPSecure = "tls";

By looking at your debug logs, you can notice that the failing PhpMailer log shows this:

SMTP -> ERROR: AUTH not accepted from server: 250 Hello []
503 AUTH command used when not advertised

While your successful PEAR log shows this:

DEBUG: Recv: 220 TLS go ahead

My guess is that explicitly asking PHPMailer to use TLS will put it on the right track.
Also, make sure you're using the latest versin of PHPMailer.

PHP: Get key from array?

Use the array_search function.

Example from

$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');

$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array);   // $key = 1;

Amazon S3 upload file and get URL

a bit old but still for anyone stumbling upon this in the future:

you can do it with one line assuming you already wrote the CredentialProvider and the AmazonS3Client.

it will look like this:

 String ImageURL = String.valueOf(s3.getUrl(
                                  ConstantsAWS3.BUCKET_NAME, //The S3 Bucket To Upload To
                                  file.getName())); //The key for the uploaded object

and if you didn't wrote the CredentialProvider and the AmazonS3Client then just add them before getting the URL like this:

  CognitoCachingCredentialsProvider credentialsProvider = new CognitoCachingCredentialsProvider(
        "POOL_ID", // Identity pool ID
        Regions.US_EAST_1 // Region

Difference between -XX:+UseParallelGC and -XX:+UseParNewGC

UseParNewGC usually knowns as "parallel young generation collector" is same in all ways as the parallel garbage collector (-XX:+UseParallelGC), except that its more sophiscated and effiecient. Also it can be used with a "concurrent low pause collector".

See Java GC FAQ, question 22 for more information.

Note that there are some known bugs with UseParNewGC

Find all paths between two graph nodes

I've implemented a version where it basically finds all possible paths from one node to the other, but it doesn't count any possible 'cycles' (the graph I'm using is cyclical). So basically, no one node will appear twice within the same path. And if the graph were acyclical, then I suppose you could say it seems to find all the possible paths between the two nodes. It seems to be working just fine, and for my graph size of ~150, it runs almost instantly on my machine, though I'm sure the running time must be something like exponential and so it'll start to get slow quickly as the graph gets bigger.

Here is some Java code that demonstrates what I'd implemented. I'm sure there must be more efficient or elegant ways to do it as well.

Stack connectionPath = new Stack();
List<Stack> connectionPaths = new ArrayList<>();
// Push to connectionsPath the object that would be passed as the parameter 'node' into the method below
void findAllPaths(Object node, Object targetNode) {
    for (Object nextNode : nextNodes(node)) {
       if (nextNode.equals(targetNode)) {
           Stack temp = new Stack();
           for (Object node1 : connectionPath)
       } else if (!connectionPath.contains(nextNode)) {
           findAllPaths(nextNode, targetNode);

How and when to use SLEEP() correctly in MySQL?

If you don't want to SELECT SLEEP(1);, you can also DO SLEEP(1); It's useful for those situations in procedures where you don't want to see output.



Servlet Mapping using web.xml

It allows servlets to have multiple servlet mappings:


It allows filters to be mapped on the particular servlet:


Your proposal would support neither of them. Note that the web.xml is read and parsed only once during application's startup, not on every HTTP request as you seem to think.

Since Servlet 3.0, there's the @WebServlet annotation which minimizes this boilerplate:

public class Servlet1 extends HttpServlet {

See also:

List files in local git repo?

This command:

git ls-tree --full-tree -r --name-only HEAD

lists all of the already committed files being tracked by your git repo.

Accessing nested JavaScript objects and arrays by string path

This is now supported by lodash using _.get(obj, property). See

Example from the docs:

var object = { 'a': [{ 'b': { 'c': 3 } }] };

_.get(object, 'a[0].b.c');
// ? 3

_.get(object, ['a', '0', 'b', 'c']);
// ? 3

_.get(object, 'a.b.c', 'default');
// ? 'default'

How do I convert a String object into a Hash object?

Ran across a similar issue that needed to use the eval().

My situation, I was pulling some data from an API and writing it to a file locally. Then being able to pull the data from the file and use the Hash.

I used to read the contents of the file into a variable. In this case creates it as a String.

Then used eval() to convert the string into a Hash.

read_handler ="Path/To/File.json")

puts read_handler.kind_of?(String) # Returns TRUE

a = eval(read_handler)

puts a.kind_of?(Hash) # Returns TRUE

puts a["Enter Hash Here"] # Returns Key => Values

puts a["Enter Hash Here"].length # Returns number of key value pairs

puts a["Enter Hash Here"]["Enter Key Here"] # Returns associated value

Also just to mention that IO is an ancestor of File. So you can also use instead if you wanted.

When is a timestamp (auto) updated?

Adding where to find UPDATE CURRENT_TIMESTAMP because for new people this is a confusion.

Most people will use phpmyadmin or something like it.

Default value you select CURRENT_TIMESTAMP

Attributes (a different drop down) you select UPDATE CURRENT_TIMESTAMP

Common Header / Footer with static HTML

No. Static HTML files don't change. You could potentially do this with some fancy Javascript AJAXy solution but that would be bad.

How to change an application icon programmatically in Android?

Programatically, you may want to publish the application launcher yourself :

Note: this method no longer works starting with Android 8.0 - Oreo

In your AndroidManifest.xml, add :

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

Then you need create your app launcher intent:

Intent myLauncherIntent = new Intent();
myLauncherIntent.setClassName("", "YourLauncherActivityName");

Create an install shortcut intent with your app launcher and custom icon:

Intent intent = new Intent();
intent.putExtra(Intent.EXTRA_SHORTCUT_INTENT, myLauncherIntent);
intent.putExtra(Intent.EXTRA_SHORTCUT_NAME, "Application Name");

And finally launch the broadcast intent:


CSS - Expand float child DIV height to parent's height

A common solution to this problem uses absolute positioning or cropped floats, but these are tricky in that they require extensive tuning if your columns change in number+size, and that you need to make sure your "main" column is always the longest. Instead, I'd suggest you use one of three more robust solutions:

  1. display: flex: by far the simplest & best solution and very flexible - but unsupported by IE9 and older.
  2. table or display: table: very simple, very compatible (pretty much every browser ever), quite flexible.
  3. display: inline-block; width:50% with a negative margin hack: quite simple, but column-bottom borders are a little tricky.

1. display:flex

This is really simple, and it's easy to adapt to more complex or more detailed layouts - but flexbox is only supported by IE10 or later (in addition to other modern browsers).


Relevant html:

<div class="parent"><div>column 1</div><div>column 2</div></div>

Relevant css:

.parent { display: -ms-flex; display: -webkit-flex; display: flex; }
.parent>div { flex:1; }

Flexbox has support for a lot more options, but to simply have any number of columns the above suffices!

2.<table> or display: table

A simple & extremely compatible way to do this is to use a table - I'd recommend you try that first if you need old-IE support. You're dealing with columns; divs + floats simply aren't the best way to do that (not to mention the fact that multiple levels of nested divs just to hack around css limitations is hardly more "semantic" than just using a simple table). If you do not wish to use the table element, consider css display: table (unsupported by IE7 and older).


Relevant html: (but consider using a plain <table> instead)

<div class="parent"><div>column 1</div><div>column 2</div></div>

Relevant css:

.parent { display: table; }
.parent > div {display: table-cell; width:50%; }
/*omit width:50% for auto-scaled column widths*/

This approach is far more robust than using overflow:hidden with floats. You can add pretty much any number of columns; you can have them auto-scale if you want; and you retain compatibility with ancient browsers. Unlike the float solution requires, you also don't need to know beforehand which column is longest; the height scales just fine.

KISS: don't use float hacks unless you specifically need to. If IE7 is an issue, I'd still pick a plain table with semantic columns over a hard-to-maintain, less flexible trick-CSS solution any day.

By the way, if you need your layout to be responsive (e.g. no columns on small mobile phones) you can use a @media query to fall back to plain block layout for small screen widths - this works whether you use <table> or any other display: table element.

3. display:inline block with a negative margin hack.

Another alternative is to use display:inline block.


Relevant html: (the absence of spaces between the div tags is significant!)

<div class="parent"><div><div>column 1</div></div><div><div>column 2</div></div></div>

Relevant css:

.parent { 
    position: relative; width: 100%; white-space: nowrap; overflow: hidden; 

.parent>div { 
    display:inline-block; width:50%; white-space:normal; vertical-align:top; 

.parent>div>div {
    padding-bottom: 32768px; margin-bottom: -32768px; 

This is slightly tricky, and the negative margin means that the "true" bottom of the columns is obscured. This in turn means you can't position anything relative to the bottom of those columns because that's cut off by overflow: hidden. Note that in addition to inline-blocks, you can achieve a similar effect with floats.

TL;DR: use flexbox if you can ignore IE9 and older; otherwise try a (css) table. If neither of those options work for you, there are negative margin hacks, but these can cause weird display issues that are easy to miss during development, and there are layout limitations you need to be aware of.

Angular exception: Can't bind to 'ngForIn' since it isn't a known native property

Try to import import { CommonModule } from '@angular/common'; in angular final as *ngFor ,*ngIf all are present in CommonModule

How to find which views are using a certain table in SQL Server (2008)?

If you need to find database objects (e.g. tables, columns, triggers) by name - have a look at the FREE Red-Gate tool called SQL Search which does this - it searches your entire database for any kind of string(s).

enter image description here

enter image description here

It's a great must-have tool for any DBA or database developer - did I already mention it's absolutely FREE to use for any kind of use??

How to utilize date add function in Google spreadsheet?

what's wrong with simple add and convert back?

if A1 is a date field, and A2 hold the number of days to add: =TO_DATE((DATEVALUE(A1)+A2)

GSON throwing "Expected BEGIN_OBJECT but was BEGIN_ARRAY"?

public ChannelSearchEnum[] getChannelSearchEnum(Response response) {
        return[].class, ObjectMapperType.GSON);

Above will solve and passing response will returned mapped object array of the class

How to align two elements on the same line without changing HTML

div {
  display: flex;
  justify-content: space-between;
  <p>Item one</p>
  <a>Item two</a>

What exactly is "exit" in PowerShell?

It's a reserved keyword (like return, filter, function, break).


Also, as per Section 7.6.4 of Bruce Payette's Powershell in Action:

But what happens when you want a script to exit from within a function defined in that script? ... To make this easier, Powershell has the exit keyword.

Of course, as other have pointed out, it's not hard to do what you want by wrapping exit in a function:

PS C:\> function ex{exit}
PS C:\> new-alias ^D ex

Store select query's output in one array in postgres

I had exactly the same problem. Just one more working modification of the solution given by Denis (the type must be specified):

SELECT column_name::text
FROM information_schema.columns
WHERE table_name='aean'

How to do a SOAP Web Service call from Java class?

Or just use Apache CXF's wsdl2java to generate objects you can use.

It is included in the binary package you can download from their website. You can simply run a command like this:

$ ./wsdl2java -p com.mynamespace.for.the.api.objects -autoNameResolution

It uses the wsdl to generate objects, which you can use like this (object names are also grabbed from the wsdl, so yours will be different a little):

DefaultWebService defaultWebService = new DefaultWebService();
String res = defaultWebService.getDefaultWebServiceHttpSoap11Endpoint().login("webservice","dadsadasdasd");

There is even a Maven plug-in which generates the sources:

Note: If you generate sources using CXF and IDEA, you might want to look at this:

How to find memory leak in a C++ code/project?

In addition to the tools and methodes provided in the other anwers, static code analysis tools can be used to detect memory leaks (and other issues as well). A free an robust tool is Cppcheck. But there are a lot of other tools available. Wikipedia has a list of static code analysis tools.

Object Required Error in excel VBA

In order to set the value of integer variable we simply assign the value to it. eg g1val = 0 where as set keyword is used to assign value to object.

Sub test()

Dim g1val, g2val As Integer

  g1val = 0
  g2val = 0

    For i = 3 To 18

     If g1val > Cells(33, i).Value Then
        g1val = g1val
       g1val = Cells(33, i).Value
     End If

    Next i

    For j = 32 To 57
        If g2val > Cells(31, j).Value Then
           g2val = g2val
          g2val = Cells(31, j).Value
        End If
    Next j

End Sub

How do I put a variable inside a string?

Oh, the many, many ways...

String concatenation:

plot.savefig('hanning' + str(num) + '.pdf')

Conversion Specifier:

plot.savefig('hanning%s.pdf' % num)

Using local variable names:

plot.savefig('hanning%(num)s.pdf' % locals()) # Neat trick

Using str.format():

plot.savefig('hanning{0}.pdf'.format(num)) # Note: This is the new preferred way

Using f-strings:

plot.savefig(f'hanning{num}.pdf') # added in Python 3.6

Using string.Template:


Type safety: Unchecked cast

Well, first of all, you're wasting memory with the new HashMap creation call. Your second line completely disregards the reference to this created hashmap, making it then available to the garbage collector. So, don't do that, use:

private Map<String, String> someMap = (HashMap<String, String>)getApplicationContext().getBean("someMap");

Secondly, the compiler is complaining that you cast the object to a HashMap without checking if it is a HashMap. But, even if you were to do:

if(getApplicationContext().getBean("someMap") instanceof HashMap) {
    private Map<String, String> someMap = (HashMap<String, String>)getApplicationContext().getBean("someMap");

You would probably still get this warning. The problem is, getBean returns Object, so it is unknown what the type is. Converting it to HashMap directly would not cause the problem with the second case (and perhaps there would not be a warning in the first case, I'm not sure how pedantic the Java compiler is with warnings for Java 5). However, you are converting it to a HashMap<String, String>.

HashMaps are really maps that take an object as a key and have an object as a value, HashMap<Object, Object> if you will. Thus, there is no guarantee that when you get your bean that it can be represented as a HashMap<String, String> because you could have HashMap<Date, Calendar> because the non-generic representation that is returned can have any objects.

If the code compiles, and you can execute String value = map.get("thisString"); without any errors, don't worry about this warning. But if the map isn't completely of string keys to string values, you will get a ClassCastException at runtime, because the generics cannot block this from happening in this case.

LINQ select in C# dictionary

One way would be to first flatten the list with a SelectMany:

subList.SelectMany(m => m).Where(k => k.Key.Equals("valueTitle"));

How to Update a Component without refreshing full page - Angular

To refresh the component at regular intervals I found this the best method. In the ngOnInit method setTimeOut function

ngOnInit(): void {
  setTimeout(() => { this.ngOnInit() }, 1000 * 10)
//10 is the number of seconds

Force IE8 Into IE7 Compatiblity Mode

There is an HTTP header you can set that will force IE8 to use IE7-compatibility mode.