Programs & Examples On #Hsm

Hardware Security Modules are devices designed to protect cryptographic key material and accelerate certain operations.

Redirect to external URL with return in laravel

If you're using InertiaJS, the away() approach won't work as seen on the inertiaJS github, they are discussing the best way to create a "external redirect" on inertiaJS, the solution for now is return a 409 status with X-Inertia-Location header informing the url, like this:

return response('', 409)
            ->header('X-Inertia-Location', $paymentLink);

Where paymentLink is the link you want to send the user to.


Google maps responsive resize

After few years, I moved to leaflet map and I have fixed this issue completely, the following could be applied to google maps too:

    var headerHeight = $("#navMap").outerHeight();
    var footerHeight = $("footer").outerHeight();
    var windowHeight = window.innerHeight;
    var mapContainerHeight = headerHeight + footerHeight;
    var totalMapHeight = windowHeight - mapContainerHeight;
    $("#map").css("margin-top", headerHeight);

        var headerHeight = $("#navMap").outerHeight();
        var footerHeight = $("footer").outerHeight();
        var windowHeight = window.innerHeight;
        var mapContainerHeight = headerHeight + footerHeight;
        var totalMapHeight = windowHeight - mapContainerHeight;
        $("#map").css("margin-top", headerHeight);

Improve SQL Server query performance on large tables

The question specifically states the performance needs to be improved for ad-hoc queries, and that indexes can't be added. So taking that at face value, what can be done to improve performance on any table?

Since we're considering ad-hoc queries, the WHERE clause and the ORDER BY clause can contain any combination of columns. This means that almost regardless of what indexes are placed on the table there will be some queries that require a table scan, as seen above in query plan of a poorly performing query.

Taking this into account, let's assume there are no indexes at all on the table apart from a clustered index on the primary key. Now let's consider what options we have to maximize performance.

  • Defragment the table

    As long as we have a clustered index then we can defragment the table using DBCC INDEXDEFRAG (deprecated) or preferably ALTER INDEX. This will minimize the number of disk reads required to scan the table and will improve speed.

  • Use the fastest disks possible. You don't say what disks you're using but if you can use SSDs.

  • Optimize tempdb. Put tempdb on the fastest disks possible, again SSDs. See this SO Article and this RedGate article.

  • As stated in other answers, using a more selective query will return less data, and should be therefore be faster.

Now let's consider what we can do if we are allowed to add indexes.

If we weren't talking about ad-hoc queries, then we would add indexes specifically for the limited set of queries being run against the table. Since we are discussing ad-hoc queries, what can be done to improve speed most of the time?

  • Add a single column index to each column. This should give SQL Server at least something to work with to improve the speed for the majority of queries, but won't be optimal.
  • Add specific indexes for the most common queries so they are optimized.
  • Add additional specific indexes as required by monitoring for poorly performing queries.


I've run some tests on a 'large' table of 22 million rows. My table only has six columns but does contain 4GB of data. My machine is a respectable desktop with 8Gb RAM and a quad core CPU and has a single Agility 3 SSD.

I removed all indexes apart from the primary key on the Id column.

A similar query to the problem one given in the question takes 5 seconds if SQL server is restarted first and 3 seconds subsequently. The database tuning advisor obviously recommends adding an index to improve this query, with an estimated improvement of > 99%. Adding an index results in a query time of effectively zero.

What's also interesting is that my query plan is identical to yours (with the clustered index scan), but the index scan accounts for 9% of the query cost and the sort the remaining 91%. I can only assume your table contains an enormous amount of data and/or your disks are very slow or located over a very slow network connection.

sqlplus error on select from external table: ORA-29913: error in executing ODCIEXTTABLEOPEN callout

Our version of Oracle is running on Red Hat Enterprise Linux. We experimented with several different types of group permissions to no avail. The /defaultdir directory had a group that was a secondary group for the oracle user. When we updated the /defaultdir directory to have a group of "oinstall" (oracle's primary group), I was able to select from the external tables underneath that directory with no problem.

So, for others that come along and might have this issue, make the directory have oracle's primary group as the group and it might resolve it for you as it did us. We were able to set the permissions to 770 on the directory and files and selecting on the external tables works fine now.

what does this mean ? image/png;base64?

It's an inlined image (png), encoded in base64. It can make a page faster: the browser doesn't have to query the server for the image data separately, saving a round trip.

(It can also make it slower if abused: these resources are not cached, so the bytes are included in each page load.)

The type initializer for 'MyClass' threw an exception

I too faced this error in two situation

  1. While performing redirection from BAL layer to DAL layer I faced this exception. Inner exception says that "Object Reference error".

  2. Web.Config file key does not match.

Hope this useful to solve your problem.

Oracle - how to remove white spaces?

It looks like you are executing the query in sqlplus. Sqlplus needs to ensure that there is enough room in the column spacing so the maximum string size can be displayed(255). Usually, the solution is to use the column formatting options(Run prior to the query: column A format A20) to reduce the maximum string size (lines that exceed this length will be displayed over multiple lines).

How to drop columns using Rails migration

Give below command it will add in migration file on its own

rails g migration RemoveColumnFromModel

After running above command you can check migration file remove_column code must be added there on its own

Then migrate the db

rake db:migrate

Linq order by, group by and order by each group?

I think you want an additional projection that maps each group to a sorted-version of the group:

.Select(group => group.OrderByDescending(student => student.Grade))

It also appears like you might want another flattening operation after that which will give you a sequence of students instead of a sequence of groups:

.SelectMany(group => group)

You can always collapse both into a single SelectMany call that does the projection and flattening together.

EDIT: As Jon Skeet points out, there are certain inefficiencies in the overall query; the information gained from sorting each group is not being used in the ordering of the groups themselves. By moving the sorting of each group to come before the ordering of the groups themselves, the Max query can be dodged into a simpler First query.

Switch statement with returns -- code correctness

I would take a different tack entirely. Don't RETURN in the middle of the method/function. Instead, just put the return value in a local variable and send it at the end.

Personally, I find the following to be more readable:

String result = "";

switch (something) {
case 0:
  result = "blah";
case 1:
  result = "foo";

return result;

How to set Status Bar Style in Swift 3

First step you need add a row with key: View controller-based status bar appearance and value NO to Info.plist file. After that, add 2 functions in your controller to specific only that controller will effect:

override func viewWillAppear(_ animated: Bool) {
       UIApplication.shared.statusBarStyle = .lightContent

override func viewWillDisappear(_ animated: Bool) {
        UIApplication.shared.statusBarStyle = .default    

How do I select last 5 rows in a table without sorting?

You can retrieve them from memory.
So first you get the rows in a DataSet, and then get the last 5 out of the DataSet.

PHP Redirect to another page after form submit

First give your input type submit a name, like this name='submitform'.

and then put this in your php file

if (isset($_POST['submitform']))
<script type="text/javascript">
window.location = "";

Don't forget to change the url to yours.

Split List into Sublists with LINQ

Here's a list splitting routine I wrote a couple months ago:

public static List<List<T>> Chunk<T>(
    List<T> theList,
    int chunkSize
    List<List<T>> result = theList
        .Select((x, i) => new {
            data = x,
            indexgroup = i / chunkSize
        .GroupBy(x => x.indexgroup, x =>
        .Select(g => new List<T>(g))

    return result;

No module named MySQLdb

pip install --user mysqlclient 

above works for me like charm for me.I go the error from sqlalchemy actually. Environment information :

Python : 3.6, Ubuntu : 16.04,conda 4.6.8

Adding days to $Date in PHP

If you're using PHP 5.3, you can use a DateTime object and its add method:

$Date1 = '2010-09-17';
$date = new DateTime($Date1);
$date->add(new DateInterval('P1D')); // P1D means a period of 1 day
$Date2 = $date->format('Y-m-d');

Take a look at the DateInterval constructor manual page to see how to construct other periods to add to your date (2 days would be 'P2D', 3 would be 'P3D', and so on).

Without PHP 5.3, you should be able to use strtotime the way you did it (I've tested it and it works in both 5.1.6 and 5.2.10):

$Date1 = '2010-09-17';
$Date2 = date('Y-m-d', strtotime($Date1 . " + 1 day"));
// var_dump($Date2) returns "2010-09-18"

How to put a delay on AngularJS instant search?

 <input type="text"
    ng-model ="criteria.searchtext""  
    ng-model-options="{debounce: {'default': 1000, 'blur': 0}}"
    placeholder="Search" >

Now we can set ng-model-options debounce with time and when blur, model need to be changed immediately otherwise on save it will have older value if delay is not completed.

How to configure logging to syslog in Python?

I fix it on my notebook. The rsyslog service did not listen on socket service.

I config this line bellow in /etc/rsyslog.conf file and solved the problem:

$SystemLogSocketName /dev/log

How do you import classes in JSP?

In the page tag:

<%@ page import="java.util.List" %>

How to keep the local file or the remote file during merge using Git and the command line?

This approach seems more straightforward, avoiding the need to individually select each file:

# keep remote files
git merge --strategy-option theirs
# keep local files
git merge --strategy-option ours


# keep remote files
git pull -Xtheirs
# keep local files
git pull -Xours

Copied directly from: Resolve Git merge conflicts in favor of their changes during a pull

Python update a key in dict if it doesn't exist

You do not need to call d.keys(), so

if key not in d:
    d[key] = value

is enough. There is no clearer, more readable method.

You could update again with dict.get(), which would return an existing value if the key is already present:

d[key] = d.get(key, value)

but I strongly recommend against this; this is code golfing, hindering maintenance and readability.

How to delete columns in a CSV file?

Off the top of my head, this will do it without any sort of error checking nor ability to configure anything. That is "left to the reader".

outFile = open( 'newFile', 'w' )
for line in open( 'oldFile' ):
   items = line.split( ',' )
   outFile.write( ','.join( items[:2] + items[ 3: ] ) )

pandas unique values multiple columns

An updated solution using numpy v1.13+ requires specifying the axis in np.unique if using multiple columns, otherwise the array is implicitly flattened.

import numpy as np

np.unique(df[['col1', 'col2']], axis=0)

This change was introduced Nov 2016:

JQuery get all elements by class name

With the code in the question, you're only dealing interacting with the first of the four entries returned by that selector.

Code below as a fiddle:

I want to be overly clear that you have four items that matched that selector, so you need to deal with each explicitly. Using eq() is a little more explicit making this point than the answers using map, though map or each is what you'd probably use "in real life" (jquery docs for eq here).

        <script src="//" ></script>

        <div class="mbox">Block One</div>
        <div class="mbox">Block Two</div>
        <div class="mbox">Block Three</div>
        <div class="mbox">Block Four</div>

        <div id="outige"></div>
            // using the $ prefix to use the "jQuery wrapped var" convention
            var i, $mvar = $('.mbox');

            // convenience method to display unprocessed html on the same page
            function logit( string )
                var text = document.createTextNode( string );


            for (i=0; i<$mvar.length; i++)    {


Output from logit calls (after the initial four div's display):

Block One
Block Two
Block Three
Block Four

How to unzip a list of tuples into individual lists?

If you want a list of lists:

>>> [list(t) for t in zip(*l)]
[[1, 3, 8], [2, 4, 9]]

If a list of tuples is OK:

>>> zip(*l)
[(1, 3, 8), (2, 4, 9)]

How to run an awk commands in Windows?

Actually, I do like mark instruction but little differently. I've added C:\Program Files (x86)\GnuWin32\bin\ to the Path variable, and try to run it with type awk using cmd.

Hope it works.

How to check if matching text is found in a string in Lua?

There are 2 options to find matching text; string.match or string.find.

Both of these perform a regex search on the string to find matches.


string.find(subject string, pattern string, optional start position, optional plain flag)

Returns the startIndex & endIndex of the substring found.

The plain flag allows for the pattern to be ignored and intead be interpreted as a literal. Rather than (tiger) being interpreted as a regex capture group matching for tiger, it instead looks for (tiger) within a string.

Going the other way, if you want to regex match but still want literal special characters (such as .()[]+- etc.), you can escape them with a percentage; %(tiger%).

You will likely use this in combination with string.sub


str = "This is some text containing the word tiger."
if string.find(str, "tiger") then
  print ("The word tiger was found.")
  print ("The word tiger was not found.")


string.match(s, pattern, optional index)

Returns the capture groups found.


str = "This is some text containing the word tiger."
if string.match(str, "tiger") then
  print ("The word tiger was found.")
  print ("The word tiger was not found.")

'Conda' is not recognized as internal or external command

I have just launched anaconda-navigator and run the conda commands from there.

Where can I set path to make.exe on Windows?

Why don't you create a bat file makedos.bat containing the following line?

c:\DOS\make.exe %1 %2 %5

and put it in C:\DOS (or C:\Windowsè or make sure that it is in your %path%)

You can run from cmd, SET and it displays all environment variables, including PATH.

In registry you can find environment variables under:

  • HKEY_CURRENT_USER\Environment
  • HKEY_CURRENT_USER\Volatile Environment
  • HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\Environment

Understanding ibeacon distancing

It's possible, but it depends on the power output of the beacon you're receiving, other rf sources nearby, obstacles and other environmental factors. Best thing to do is try it out in the environment you're interested in.

Validate decimal numbers in JavaScript - IsNumeric()

If I'm not mistaken, this should match any valid JavaScript number value, excluding constants (Infinity, NaN) and the sign operators +/- (because they are not actually part of the number as far as I concerned, they are separate operators):

I needed this for a tokenizer, where sending the number to JavaScript for evaluation wasn't an option... It's definitely not the shortest possible regular expression, but I believe it catches all the finer subtleties of JavaScript's number syntax.


Valid numbers would include:

 - 0
 - 00
 - 01
 - 10
 - 0e1
 - 0e01
 - .0
 - 0.
 - .0e1
 - 0.e1
 - 0.e00
 - 0xf
 - 0Xf

Invalid numbers would be

 - 00e1
 - 01e1
 - 00.0
 - 00x0
 - .
 - .e0

Determine Whether Integer Is Between Two Other Integers?

Your operator is incorrect. Should be if number >= 10000 and number <= 30000:. Additionally, Python has a shorthand for this sort of thing, if 10000 <= number <= 30000:.

How to skip the first n rows in sql query

In Faircom SQL (which is a pseudo MySQL), i can do this in a super simple SQL Statement, just as follows:


Obviously you can just replace 10 with any declared variable of your desire.

I don't have access to MS SQL or other platforms, but I'll be really surprised MS SQL doesn't support something like this.

What is a constant reference? (not a reference to a constant)

This code is ill-formed:

int&const icr=i;

Reference: C++17 [dcl.ref]/1:

Cv-qualified references are ill-formed except when the cv-qualifiers are introduced through the use of a typedef-name or decltype-specifier, in which case the cv-qualifiers are ignored.

This rule has been present in all standardized versions of C++. Because the code is ill-formed:

  • you should not use it, and
  • there is no associated behaviour.

The compiler should reject the program; and if it doesn't, the executable's behaviour is completely undefined.

NB: Not sure how none of the other answers mentioned this yet... nobody's got access to a compiler?

Hash String via SHA-256 in Java

When using hashcodes with any jce provider you first try to get an instance of the algorithm, then update it with the data you want to be hashed and when you are finished you call digest to get the hash value.

MessageDigest sha = MessageDigest.getInstance("SHA-256");
byte[] digest = sha.digest();

you can use the digest to get a base64 or hex encoded version according to your needs

How to make bootstrap column height to 100% row height?

@Alan's answer will do what you're looking for, but this solution fails when you use the responsive capabilities of Bootstrap. In your case, you're using the xs sizes so you won't notice, but if you used anything else (e.g. col-sm, col-md, etc), you'd understand.

Another approach is to play with margins and padding. See the updated fiddle:

.left-side {
  background-color: blue;
  padding-bottom: 1000px;
  margin-bottom: -1000px;
  height: 100%;
.something {
  height: 100%;
  background-color: red;
  padding-bottom: 1000px;
  margin-bottom: -1000px;
  height: 100%;
.row {
  background-color: green;
  overflow: hidden;

javascript remove "disabled" attribute from html input

Why not just remove that attribute?

  1. vanilla JS: elem.removeAttribute('disabled')
  2. jQuery: elem.removeAttr('disabled')

How do I get into a Docker container's shell?

docker attach will let you connect to your Docker container, but this isn't really the same thing as ssh. If your container is running a webserver, for example, docker attach will probably connect you to the stdout of the web server process. It won't necessarily give you a shell.

The docker exec command is probably what you are looking for; this will let you run arbitrary commands inside an existing container. For example:

docker exec -it <mycontainer> bash

Of course, whatever command you are running must exist in the container filesystem.

In the above command <mycontainer> is the name or ID of the target container. It doesn't matter whether or not you're using docker compose; just run docker ps and use either the ID (a hexadecimal string displayed in the first column) or the name (displayed in the final column). E.g., given:

$ docker ps
d2d4a89aaee9        larsks/mini-httpd   "mini_httpd -d /cont   7 days ago          Up 7 days                               web                 

I can run:

$ docker exec -it web ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
18: eth0: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP 
    link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff
    inet scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:acff:fe11:3/64 scope link 
       valid_lft forever preferred_lft forever

I could accomplish the same thing by running:

$ docker exec -it d2d4a89aaee9 ip addr

Similarly, I could start a shell in the container;

$ docker exec -it web sh
/ # echo This is inside the container.
This is inside the container.
/ # exit

How can I tail a log file in Python?

So, this is coming quite late, but I ran into the same problem again, and there's a much better solution now. Just use pygtail:

Pygtail reads log file lines that have not been read. It will even handle log files that have been rotated. Based on logcheck's logtail2 (

Enum String Name from Value

Just need:

string stringName = EnumDisplayStatus.Visible.ToString("f");
// stringName == "Visible"

Access 2010 VBA query a table and iterate through results

Ahh. Because I missed the point of you initial post, here is an example which also ITERATES. The first example did not. In this case, I retreive an ADODB recordset, then load the data into a collection, which is returned by the function to client code:

EDIT: Not sure what I screwed up in pasting the code, but the formatting is a little screwball. Sorry!

Public Function StatesCollection() As Collection
Dim cn As ADODB.Connection
Dim cmd As ADODB.Command
Dim rs As ADODB.Recordset
Dim colReturn As New Collection

Set colReturn = New Collection

Dim SQL As String
SQL = _
    "SELECT tblState.State, tblState.StateName " & _
    "FROM tblState"

Set cn = New ADODB.Connection
Set cmd = New ADODB.Command

With cn
    .Provider = DataConnection.MyADOProvider
    .ConnectionString = DataConnection.MyADOConnectionString
End With

With cmd
    .CommandText = SQL
    .ActiveConnection = cn
End With

Set rs = cmd.Execute

With rs
    If Not .EOF Then
    Do Until .EOF
        colReturn.Add Nz(!State, "")
    End If
End With

Set rs = Nothing
Set cn = Nothing

Set StatesCollection = colReturn

End Function

RAW POST using cURL in PHP

Implementation with Guzzle library:

use GuzzleHttp\Client;
use GuzzleHttp\RequestOptions;

$httpClient = new Client();

$response = $httpClient->post(
        RequestOptions::BODY => 'POST raw request content',
        RequestOptions::HEADERS => [
            'Content-Type' => 'application/x-www-form-urlencoded',


PHP CURL extension:

$curlHandler = curl_init();

curl_setopt_array($curlHandler, [
    CURLOPT_URL => '',

     * Specify POST method
    CURLOPT_POST => true,

     * Specify request content
    CURLOPT_POSTFIELDS => 'POST raw request content',

$response = curl_exec($curlHandler);



Source code

Cannot inline bytecode built with JVM target 1.8 into bytecode that is being built with JVM target 1.6

Feb 2020
android 3.4+
Go to File -> Settings -> Kotlin Compiler -> Target JVM Version > set to 1.8 and then make sure to do File -> Sync project with Gradle files

Or add this into build.gradle(module:app) in android block:

kotlinOptions {
           jvmTarget = "1.8"

How can I keep Bootstrap popovers alive while being hovered?

Vikas answer works perfectly for me, here I also add support for the delay (show / hide).

var popover = $('#example');
var options = {
    animation : true,
    html: true,
    trigger: 'manual',
    placement: 'right',
    delay: {show: 500, hide: 100}
    .on("mouseenter", function () {

        var t = this;
        var popover = $(this);    
        setTimeout(function () {

            if (":hover")) {

                popover.siblings(".popover").on("mouseleave", function () {
    .on("mouseleave", function () {
        var t = this;
        var popover = $(this);

        setTimeout(function () {
            if (popover.siblings(".popover").length && !popover.siblings(".popover").is(":hover")) {
        }, options.delay.hide);

Also please pay attention I changed:

if (!$(".popover:hover").length) {


if (popover.siblings(".popover").length && !popover.siblings(".popover").is(":hover")) {

so that it references exactly at that opened popover, and not any other (since now, through the delay, more than 1 could be open at the same time)

How do I resolve a path relative to an ASP.NET MVC 4 application root?

To get the absolute path use this:

String path = HttpContext.Current.Server.MapPath("~/Data/data.html");


To get the Controller's Context remove .Current from the above line. By using HttpContext by itself it's easier to Test because it's based on the Controller's Context therefore more localized.

I realize now that I dislike how Server.MapPath works (internally eventually calls HostingEnvironment.MapPath) So I now recommend to always use HostingEnvironment.MapPath because its static and not dependent on the context unless of course you want that...

How do I get the path of the assembly the code is in?

in a windows form app, you can simply use Application.StartupPath

but for DLLs and console apps the code is much harder to remember...

string slash = Path.DirectorySeparatorChar.ToString();
string root = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);

root += slash;
string settingsIni = root + "settings.ini"

How do I implement charts in Bootstrap?

I would like to suggest you to use HighCharts. It's just awesome and easy to integrate.



<script src=""></script>
<script src=""></script>

<div id="container" style="min-width: 310px; height: 400px; margin: 0 auto"></div>


$(function () {
            chart: {
                type: 'column'
            title: {
                text: 'Monthly Average Rainfall'
            subtitle: {
                text: 'Source:'
            xAxis: {
                categories: [
            yAxis: {
                min: 0,
                title: {
                    text: 'Rainfall (mm)'
            tooltip: {
                headerFormat: '<span style="font-size:10px">{point.key}</span><table>',
                pointFormat: '<tr><td style="color:{series.color};padding:0">{}: </td>' +
                    '<td style="padding:0"><b>{point.y:.1f} mm</b></td></tr>',
                footerFormat: '</table>',
                shared: true,
                useHTML: true
            plotOptions: {
                column: {
                    pointPadding: 0.2,
                    borderWidth: 0
            series: [{
                name: 'Tokyo',
                data: [49.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4]

            }, {
                name: 'New York',
                data: [83.6, 78.8, 98.5, 93.4, 106.0, 84.5, 105.0, 104.3, 91.2, 83.5, 106.6, 92.3]

            }, {
                name: 'London',
                data: [48.9, 38.8, 39.3, 41.4, 47.0, 48.3, 59.0, 59.6, 52.4, 65.2, 59.3, 51.2]

            }, {
                name: 'Berlin',
                data: [42.4, 33.2, 34.5, 39.7, 52.6, 75.5, 57.4, 60.4, 47.6, 39.1, 46.8, 51.1]


And here is the fiddle .

apache server reached MaxClients setting, consider raising the MaxClients setting

Here's an approach that could resolve your problem, and if not would help with troubleshooting.

  1. Create a second Apache virtual server identical to the current one

  2. Send all "normal" user traffic to the original virtual server

  3. Send special or long-running traffic to the new virtual server

Special or long-running traffic could be report-generation, maintenance ops or anything else you don't expect to complete in <<1 second. This can happen serving APIs, not just web pages.

If your resource utilization is low but you still exceed MaxClients, the most likely answer is you have new connections arriving faster than they can be serviced. Putting any slow operations on a second virtual server will help prove if this is the case. Use the Apache access logs to quantify the effect.

How Do I Convert an Integer to a String in Excel VBA?

In my case, the function CString was not found. But adding an empty string to the value works, too.

Dim Test As Integer, Test2 As Variant
Test = 10
Test2 = Test & ""
//Test2 is now "10" not 10

Implement a loading indicator for a jQuery AJAX call

I solved the same problem following this example:

This example uses the jQuery JavaScript library.

First, create an Ajax icon using the AjaxLoad site.
Then add the following to your HTML :

<img src="/images/loading.gif" id="loading-indicator" style="display:none" />

And the following to your CSS file:

#loading-indicator {
  position: absolute;
  left: 10px;
  top: 10px;

Lastly, you need to hook into the Ajax events that jQuery provides; one event handler for when the Ajax request begins, and one for when it ends:

$(document).ajaxSend(function(event, request, settings) {

$(document).ajaxComplete(function(event, request, settings) {

This solution is from the following link. How to display an animated icon during Ajax request processing

Avoid web.config inheritance in child web application using inheritInChildApplications

If (as I understand) you're trying to completely block inheritance in the web config of your child application, I suggest you to avoid using the tag in web.config. Instead create a new apppool and edit the applicationHost.config file (located in %WINDIR%\System32\inetsrv\Config and %WINDIR%\SysWOW64\inetsrv\config). You just have to find the entry for your apppool and add the attribute enableConfigurationOverride="false" like in the following example:

<add name="MyAppPool" autoStart="true" managedRuntimeVersion="v4.0" managedPipelineMode="Integrated" enableConfigurationOverride="false">
    <processModel identityType="NetworkService" />

This will avoid configuration inheritance in the applications served by MyAppPool.


Problem in running .net framework 4.0 website on iis 7.0

If you look in the ISAPI And CGI Restrictions, and everything is already set to Allowed, and the ASP.NET installed is v4.0.30319, then in the right, at the "Actions" panel click in the "Edit Feature Settings..." and check both boxes. In my case, they were not.

Change bundle identifier in Xcode when submitting my first app in IOS

Xcode 7

Select root node of your project -> In editor click on project name -> Select targets -> Identity -> Bundle Identifier

What is the simplest method of inter-process communication between 2 C# processes?

The easiest solution in C# for inter-process communication when security is not a concern and given your constraints (two C# processes on the same machine) is the Remoting API. Now Remoting is a legacy technology (not the same as deprecated) and not encouraged for use in new projects, but it does work well and does not require a lot of pomp and circumstance to get working.

There is an excellent article on MSDN for using the class IpcChannel from the Remoting framework (credit to Greg Beech for the find here) for setting up a simple remoting server and client.

I Would suggest trying this approach first, and then try to port your code to WCF (Windows Communication Framework). Which has several advantages (better security, cross-platform), but is necessarily more complex. Luckily MSDN has a very good article for porting code from Remoting to WCF.

If you want to dive in right away with WCF there is a great tutorial here.

How to properly ignore exceptions

First I quote the answer of Jack o'Connor from this thread. The referenced thread got closed so I write here:

"There's a new way to do this coming in Python 3.4:

from contextlib import suppress

with suppress(Exception):
    # your code

Here's the commit that added it:

And here's the author, Raymond Hettinger, talking about this and all sorts of other Python hotness:

My addition to this is the Python 2.7 equivalent:

from contextlib import contextmanager

def ignored(*exceptions):
    except exceptions:

Then you use it like in Python 3.4:

with ignored(Exception):
    # your code

selectOneMenu ajax events

The PrimeFaces ajax events sometimes are very poorly documented, so in most cases you must go to the source code and check yourself.

p:selectOneMenu supports change event:

<p:selectOneMenu ..>
    <p:ajax event="change" update="msgtext"
        listener="#{post.subjectSelectionChanged}" />

which triggers listener with AjaxBehaviorEvent as argument in signature:

public void subjectSelectionChanged(final AjaxBehaviorEvent event)  {...}

How to properly express JPQL "join fetch" with "where" clause as JPA 2 CriteriaQuery?

I will show visually the problem, using the great example from James answer and adding the alternative solution.

When you do the follow query, without the FETCH:

Select e from Employee e 
join e.phones p 
where p.areaCode = '613'

You will have the follow results from Employee as you expected:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613
1 James 6 416

But when you add the FETCH word on JOIN, this is what happens:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613

The generated SQL is the same for the two queries, but the Hibernate removes on memory the 416 register when you use WHERE on the FETCH join.

So, to bring all phones and apply the WHERE correctly, you need to have two JOINs: one for the WHERE and another for the FETCH. Like:

Select e from Employee e 
join e.phones p 
join fetch e.phones      //no alias, to not commit the mistake
where p.areaCode = '613'

How to download Google Play Services in an Android emulator?

To the latest setup and information if you have installed the Android Studio (i.e. 1.5) and trying to target SDK 4.0 then you may not be able to locate and setup the and AVD Emulator with SDK-vX.XX (with Google API's).

See following steps in order to download the required library and start with that. AVD Emulator setup -setting up Emulator for SDK4.0 with GoogleAPI so Map application can work- In Android Studio

But unfortunately above method did not work well on my side. And was not able to created Emulator with API Level 17 (SDK 4.2). So I followed this post that worked on my side well. The reason seems that the Android Studio Emulator creation window has limited options/features.

Google Play Services in emulator, implementing Google Plus login button etc

How can I capitalize the first letter of each word in a string using JavaScript?


You could simply use a regular expression function to change the capitalization of each letter. With V8 JIST optimizations, this should prove to be the fast and memory efficient.

// Only works on Latin-I strings
'tHe VeRy LOOong StRINg'.replace(/\b[a-z]|['_][a-z]|\B[A-Z]/g, function(x){return x[0]==="'"||x[0]==="_"?x:String.fromCharCode(x.charCodeAt(0)^32)})

Or, as a function:

// Only works for Latin-I strings
var fromCharCode = String.fromCharCode;
var firstLetterOfWordRegExp = /\b[a-z]|['_][a-z]|\B[A-Z]/g;
function toLatin1UpperCase(x){ // avoid frequent anonymous inline functions
    var charCode = x.charCodeAt(0);
    return charCode===39 ? x : fromCharCode(charCode^32);
function titleCase(string){
    return string.replace(firstLetterOfWordRegExp, toLatin1UpperCase);

According to this benchmark, the code is over 33% faster than the next best solution in Chrome.

<textarea id="input" type="text">I'm a little tea pot</textarea><br /><br />_x000D_
<textarea id="output" type="text" readonly=""></textarea>_x000D_
    "use strict"_x000D_
    var fromCode = String.fromCharCode;_x000D_
    function upper(x){return x[0]==="'"?x:fromCode(x.charCodeAt(0) ^ 32)}_x000D_
    (input.oninput = function(){_x000D_
      output.value = input.value.replace(/\b[a-z]|['_][a-z]|\B[A-Z]/g, upper);_x000D_

Controlling Spacing Between Table Cells

Check this fiddle. You are going to need to take a look at using border-collapse and border-spacing. There are some quirks for IE (as usual). This is based on an answer to this question.

table.test td {
  background-color: lime;
  margin: 12px 12px 12px 12px;
  padding: 12px 12px 12px 12px;

table.test {
  border-collapse: separate;
  border-spacing: 10px;
  *border-collapse: expression('separate', cellSpacing='10px');
<table class="test">

What is the difference between JSF, Servlet and JSP?

Java Server Pages (JSP) is java technology which enables Web developers and designers to rapidly develop and easily maintain, information-rich, dynamic Web pages that leverage existing business systems. JSP technology separates the user interface from content generation, enabling designers to change the overall page layout without altering the underlying dynamic content.

Facelets is the first non JSP page declaration language designed for JSF (Java Server Faces) which provided a simpler and more powerful programming model to JSF developers as compare to JSP. It resolves different issues occurs in JSP for web applications development.

Here is a table that compares the features of scriplets and facelets:

enter image description here Source

Foreach loop, determine which is the last iteration of the loop

How to convert foreach to react to the last element:

List<int> myList = new List<int>() {1, 2, 3, 4, 5};
Console.WriteLine("foreach version");
    foreach (var current in myList)
Console.WriteLine("equivalent that reacts to last element");
    var enumerator = myList.GetEnumerator();
    if (enumerator.MoveNext() == true) // Corner case: empty list.
        while (true)
            int current = enumerator.Current;

            // Handle current element here.

            bool ifLastElement = (enumerator.MoveNext() == false);
            if (ifLastElement)
                // Cleanup after last element
                Console.WriteLine("[last element]");

MySQL Server has gone away when importing large sql file

i got a similar error.. to solve this just open my.ini at line no 36 change the value of maximum allowed packet size ie. max_allowed_packet = 20M

How to add white spaces in HTML paragraph

This can be done easily and cleanly with float.



    <li>Item 1 <span class="right">(1)</span></li>
    <li>Item 2 <span class="right">(2)</span></li>


ul {
    width: 10em
.right {
    float: right

Extending the User model with custom fields in Django

It's too late, but my answer is for those who search for a solution with a recent version of Django.

from django.db import models
from django.contrib.auth.models import User
from django.db.models.signals import post_save
from django.dispatch import receiver

class Profile(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    extra_Field_1 = models.CharField(max_length=25, blank=True)
    extra_Field_2 = models.CharField(max_length=25, blank=True)

@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
    if created:

@receiver(post_save, sender=User)
def save_user_profile(sender, instance, **kwargs):

you can use it in templates like this:

<h2>{{ user.get_full_name }}</h2>
  <li>Username: {{ user.username }}</li>
  <li>Location: {{ user.profile.extra_Field_1 }}</li>
  <li>Birth Date: {{ user.profile.extra_Field_2 }}</li>

and in like this:

def update_profile(request, user_id):
    user = User.objects.get(pk=user_id)
    user.profile.extra_Field_1 = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit...'

How to fix "Headers already sent" error in PHP

Instead of the below line



echo("<script>location.href = '".ADMIN_URL."/index.php?msg=$msg';</script>");


?><script><?php echo("location.href = '".ADMIN_URL."/index.php?msg=$msg';");?></script><?php

It'll definitely solve your problem. I faced the same problem but I solved through writing header location in the above way.

Why there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT clause?

This is the limitation in MYSQL 5.5 version. You need to update the version to 5.6.


I was getting this error in adding a table in MYSQL

Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause My new MYSQL

table looks something like this.

create table table_name (col1 int(5) auto_increment primary key, col2 varchar(300), col3 varchar(500), col4 int(3), col5 tinyint(2), col6 timestamp default current_timestamp, col7 timestamp default current_timestamp on update current_timestamp, col8 tinyint(1) default 0, col9 tinyint(1) default 1);

After some time of reading about changes in different MYSQL versions and some of the googling. I found out that there was some changes that were made in MYSQL version 5.6 over version 5.5.

This article will help you to resolve the issue.

How to include SCSS file in HTML

You can't have a link to SCSS File in your HTML page.You have to compile it down to CSS First. No there are lots of video tutorials you might want to check out. Lynda provides great video tutorials on SASS. there are also free screencasts you can google...

For official documentation visit this site And why have you chosen notepad to write Sass?? you can easily download some free text editors for better code handling.

JavaScriptSerializer - JSON serialization of enum as string

This version of Stephen's answer doesn't change the name in the JSON:

    Namespace = 
class Person
    int Age { get; set; }

    Gender Gender { get; set; }

    [DataMember(Name = "Gender")]
    string GenderString
        get { return this.Gender.ToString(); }
            Gender g; 
            this.Gender = Enum.TryParse(value, true, out g) ? g : Gender.Male; 

How to select a record and update it, with a single queryset in Django?

only in a case in serializer things, you can update in very simple way!

my_model_serializer = MyModelSerializer(
    instance=my_model, data=validated_data)
if my_model_serializer.is_valid():

only in a case in form things!

instance = get_object_or_404(MyModel, id=id)
form = MyForm(request.POST or None, instance=instance)
if form.is_valid():

Asynchronous vs synchronous execution, what does it really mean?

I created a gif for explain this, hope to be helpful: look, line 3 is asynchronous and others are synchronous. all lines before line 3 should wait until before line finish its work, but because of line 3 is asynchronous, next line (line 4), don't wait for line 3, but line 5 should wait for line 4 to finish its work, and line 6 should wait for line 5 and 7 for 6, because line 4,5,6,7 are not asynchronous. line 3 is asynchronous and others are synchronous

TortoiseGit-git did not exit cleanly (exit code 1)

For My case i did 3 steps to achieve the sucessful build.

  1. revert all the local changes if any (or just keep a copy of it in case you need it for future use)

  2. Do a git clean up, do a pull and check the logs for error

  3. GO to the git bash option and the error i was getting in log in above stem (i my case ) as "error: cannot lock ref and the branch details", so in the git bash i ran the following command git update-ref -d 'Branch_name'

For example if the error was something like **


**error: cannot lock ref 'refs/remotes/origin/EXMPLEISSUE/EXAMPLE-1011_DEMO_web_interface_DOES_NOT_GET_GIT_UPDATE':

Then i ran following command git update-ref -d 'refs/remotes/origin/EXMPLEISSUE/EXAMPLE-1011_DEMO_web_interface_DOES_NOT_GET_GIT_UPDATE'

We have to ensure all the error in logs to be solved similarly before getting a successful pull by doing git update-ref -d 'Branch_name' and finally i can get the take the successful pull from git.

How to index characters in a Golang string?

You can also try typecasting it with string.

package main

import "fmt"

func main() {

Apache default VirtualHost

The other answers here didn't work for me, but I found a pretty simple solution that did work.

I made the default one the last one listed, and I gave it ServerAlias *.

For example:

NameVirtualHost *:80

<VirtualHost *:80>
    ServerAlias *
    DocumentRoot /home/secondwebsite/web

<VirtualHost *:80>
    ServerAlias *
    DocumentRoot /home/defaultwebsite/web

If the visitor didn't explicitly choose to go to something ending in, they get the default website.

Make the image go behind the text and keep it in center using CSS

Well, put your image in the background of your website/container and put whatever you want on top of that.

Your container defined in HTML:

<div id="container">
   <input name="box" type="textbox" />
   <input name="box" type="textbox" />
   <input name="submit" type="submit" />

Your CSS would look like this:

#container {

For this to work though, you must have height and width specified to certain values (i.e. no percentages). I could help you more specifically if you wanted, but I'd need more info.

Run local java applet in browser (chrome/firefox) "Your security settings have blocked a local application from running"

After reading Java 7 Update 21 Security Improvements in Detail mention..

With the introduced changes it is most likely that no end-user is able to run your application when they are either self-signed or unsigned.

..I was wondering how this would go for loose class files - the 'simplest' applets of all.

Local file system

Dialog: Your security settings have blocked a local application from running
Your security settings have blocked a local application from running

That is the dialog seen for an applet consisting of loose class files being loaded off the local file system when the JRE is set to the default 'High' security setting.

Note that a slight quirk of the JRE only produced that on point 3 of.

  1. Load the applet page to see a broken applet symbol that leads to an empty console.
    Open the Java settings and set the level to Medium.
    Close browser & Java settings.
  2. Load the applet page to see the applet.
    Open the Java settings and set the level to High.
    Close browser & Java settings.
  3. Load the applet page to see a broken applet symbol & the above dialog.


If you load the simple applet (loose class file) seen at this resizable applet demo off the internet - which boasts an applet element of:

    alt="Pluggable Look'n'Feel Changer appears here if Java is enabled"
<p>Pluggable Look'n'Feel Changer appears here in a Java capable browser.</p>

It also seems to load successfully. Implying that:-

Applets loaded from the local file system are now subject to a stricter security sandbox than those loaded from the internet or a local server.

Security settings descriptions

As of Java 7 update 51.

  • Very High: Most secure setting - Only Java applications identified by a non-expired certificate from a trusted authority will be allowed to run.
  • High (minimum recommended): Java applications identified by a certificate from a trusted authority will be allowed to run.
  • Medium - All Java applications will be allowed to run after presenting a security prompt.

Generate C# class from XML

You should consider svcutil (svcutil question)

Both xsd.exe and svcutil operate on the XML schema file (.xsd). Your XML must conform to a schema file to be used by either of these two tools.

Note that various 3rd party tools also exist for this.

X close button only using css

True CSS with proper semantic and accessibility settings.

It is a <button>, It has text for screen readers.

button {
  width: 2rem;
  height: 2rem;
  padding: 0;
  position: absolute;
  top: 1rem;
  right: 1rem;
  cursor: pointer;

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;

button::after {
    content: '';
    width: 1px;
    height: 100%;
    background: #333;
    display: block;
    transform: rotate(45deg) translateX(0px);
    position: absolute;
    left: 50%;
    top: 0;

button::after {
    transform: rotate(-45deg) translateX(0px);

/* demo */
body {
  background: black;
.pane {
  margin: 0 auto;
  width: 50vw;
  min-height: 50vh;
  background: #FFF;
  position: relative;
  border-radius: 5px;
<div class="pane">
  <button type="button"><span class="sr-only">Close</span></button>

How to get the file extension in PHP?

This will work as well:

$array = explode('.', $_FILES['image']['name']);
$extension = end($array);

Accessing certain pixel RGB value in openCV

The current version allows the cv::Mat::at function to handle 3 dimensions. So for a Mat object m,<uchar>(0,0,0) should work.

How to check if object has been disposed in C#

The reliable solution is catching the ObjectDisposedException.

The solution to write your overridden implementation of the Dispose method doesn't work, since there is a race condition between the thread calling Dispose method and the one accessing to the object: after having checked the hypothetic IsDisposed property , the object could be really disposed, throwing the exception all the same.

Another approach could be exposing a hypothetic event Disposed (like this), which is used to notify about the disposing object to every object interested, but this could be difficoult to plan depending on the software design.

When do I need a fb:app_id or fb:admins?

Including the fb:app_id tag in your HTML HEAD will allow the Facebook scraper to associate the Open Graph entity for that URL with an application. This will allow any admins of that app to view Insights about that URL and any social plugins connected with it.

The fb:admins tag is similar, but allows you to just specify each user ID that you would like to give the permission to do the above.

You can include either of these tags or both, depending on how many people you want to admin the Insights, etc. A single as fb:admins is pretty much a minimum requirement. The rest of the Open Graph tags will still be picked up when people share and like your URL, however it may cause problems in the future, so please include one of the above.

fb:admins is specified like this:
<meta property="fb:admins" content="USER_ID"/>
<meta property="fb:admins" content="USER_ID,USER_ID2,USER_ID3"/>

and fb:app_id like this:
<meta property="fb:app_id" content="APPID"/>

Get HTML5 localStorage keys

We can also read by the name.

Say we have saved the value with name 'user' like this

localStorage.setItem('user', user_Detail);

Then we can read it by using


I used it and it is working smooth, no need to do the for loop

Remove row lines in twitter bootstrap

This is what worked for me..

  border-top: none !important; 
  border-bottom: none !important; 

Had to whip out the !important to make it stick.

Open text file and program shortcut in a Windows batch file

The command-line syntax for opening a text file is:

type filename.txt

File types supported by this command include (but are not limited to): .doc, .txt, .html, .log

If the contents is too long, you can add "|more" after "type filename.txt", and it will pause after each screen; to end the command before the end of the file, you can hold Ctrl + C.

Hiding a button in Javascript

when you press the button so it should call function that will alert message. so after alert put style visible property . you can achieve it using

function OpenAlert(){_x000D_
        alert("Getting the message");_x000D_
 <input type="button" id="getMessage" name="GetMessage" value="GetMessage" onclick="OpenAlert()"/>

Hope this will help . Happy to help

Replace non-numeric with empty string

You can do it easily with regex:

string subject = "(913)-444-5555";
string result = Regex.Replace(subject, "[^0-9]", ""); // result = "9134445555"

How does java do modulus calculations with negative numbers?

Since "mathematically" both are correct:

-13 % 64 = -13 (on modulus 64)  
-13 % 64 = 51 (on modulus 64)

One of the options had to be chosen by Java language developers and they chose:

the sign of the result equals the sign of the dividend.

Says it in Java specs:

How to read a single character from the user?

The ActiveState's recipe seems to contain a little bug for "posix" systems that prevents Ctrl-C from interrupting (I'm using Mac). If I put the following code in my script:


I will never be able to terminate the script with Ctrl-C, and I have to kill my terminal to escape.

I believe the following line is the cause, and it's also too brutal:


Asides from that, package tty is not really needed, termios is enough to handle it.

Below is the improved code that works for me (Ctrl-C will interrupt), with the extra getche function that echo the char as you type:

if sys.platform == 'win32':
    import msvcrt
    getch = msvcrt.getch
    getche = msvcrt.getche
    import sys
    import termios
    def __gen_ch_getter(echo):
        def __fun():
            fd = sys.stdin.fileno()
            oldattr = termios.tcgetattr(fd)
            newattr = oldattr[:]
                if echo:
                    # disable ctrl character printing, otherwise, backspace will be printed as "^?"
                    lflag = ~(termios.ICANON | termios.ECHOCTL)
                    lflag = ~(termios.ICANON | termios.ECHO)
                newattr[3] &= lflag
                termios.tcsetattr(fd, termios.TCSADRAIN, newattr)
                ch =
                if echo and ord(ch) == 127: # backspace
                    # emulate backspace erasing
                    sys.stdout.write('\b \b')
                termios.tcsetattr(fd, termios.TCSADRAIN, oldattr)
            return ch
        return __fun
    getch = __gen_ch_getter(False)
    getche = __gen_ch_getter(True)


Identifying country by IP address

Amazon's CloudFront content delivery network can now be configured to pass this information through as a header. Given Amazon's size (they're big and stable, not going anywhere) and this is configuration over code (no third-party API to learn or code to maintain), all around believe this to be the best option.

If you do not use AWS CloudFront, I'd look into seeing if your CDN has a similar header option that can be turned on. Usually the large providers are quick to push for feature parity. And if you are not using a CDN, you could put CloudFront in front of your infrastructure and simply set the origin to resolve to whatever you are currently using.

Additionally, it also makes sense to resolve this at the CDN level. Your CDN is already having to figure out geo location to route the user to the nearest content node, might as well pass this information along and not figure it out twice through a third party API (this becomes chokepoint for your app, waiting for a geo location lookup to resolve). No need to do this work twice (and the second time, arguably less resilient [e.g., 3rd party geo lookup]).

Geo-Targeting – CloudFront will detect the user’s country of origin and pass along the county code to you in the CloudFront-Viewer-Country header. You can use this information to customize your responses without having to use URLs that are specific to each country.

No serializer found for class org.hibernate.proxy.pojo.javassist.Javassist?

It could be your Hibernate entity relationship causing the issue...simply stop lazy loading of that related entity...for example...I resolved below by setting lazy="false" for customerType.

<class name="Customer" table="CUSTOMER">
        <id name="custId" type="long">
            <column name="CUSTID" />
            <generator class="assigned" />
        <property name="name" type="java.lang.String">
            <column name="NAME" />
        <property name="phone" type="java.lang.String">
            <column name="PHONE" />
        <property name="pan" type="java.lang.String">
            <column name="PAN" />

        <many-to-one name="customerType" not-null="true" lazy="false"></many-to-one>

How to use jQuery to get the current value of a file input field

In Chrome 8 the path is always 'C:\fakepath\' with the correct file name.

SSL certificate rejected trying to access GitHub over HTTPS behind firewall

I know the original question lists Cygwin, but here is the solution for CentOS:

curl -o /etc/pki/tls/certs/ca-bundle.crt


How to debug Javascript with IE 8

I was hoping to add this as a comment to Marcus Westin's reply, but I can't find a link - maybe I need more reputation?

Anyway, thanks, I found this code snippet useful for quick debugging in IE. I have made some quick tweaks to fix a problem that stopped it working for me, also to scroll down automatically and use fixed positioning so it will appear in the viewport. Here's my version in case anyone finds it useful:

myLog = function() {

    var _div = null;

    this.toJson = function(obj) {

        if (typeof window.uneval == 'function') { return uneval(obj); }
        if (typeof obj == 'object') {
            if (!obj) { return 'null'; }
            var list = [];
            if (obj instanceof Array) {
                    for (var i=0;i < obj.length;i++) { list.push(this.toJson(obj[i])); }
                    return '[' + list.join(',') + ']';
            } else {
                    for (var prop in obj) { list.push('"' + prop + '":' + this.toJson(obj[prop])); }
                    return '{' + list.join(',') + '}';
        } else if (typeof obj == 'string') {
            return '"' + obj.replace(/(["'])/g, '\\$1') + '"';
        } else {
            return new String(obj);


    this.createDiv = function() {

        myLog._div = document.body.appendChild(document.createElement('div'));

        var props = {
            position:'fixed', top:'10px', right:'10px', background:'#333', border:'5px solid #333', 
            color: 'white', width: '400px', height: '300px', overflow: 'auto', fontFamily: 'courier new',
            fontSize: '11px', whiteSpace: 'nowrap'

        for (var key in props) {[key] = props[key]; }


    if (!myLog._div) { this.createDiv(); }

    var logEntry = document.createElement('span');

    for (var i=0; i < arguments.length; i++) {
        logEntry.innerHTML += this.toJson(arguments[i]) + '<br />';

    logEntry.innerHTML += '<br />';


    // Scroll automatically to the bottom
    myLog._div.scrollTop = myLog._div.scrollHeight;


Git clone without .git directory

since you only want the files, you don't need to treat it as a git repo.

rsync -rlp --exclude '.git' user@host:path/to/git/repo/ .

and this only works with local path and remote ssh/rsync path, it may not work if the remote server only provides git:// or https:// access.

C++ terminate called without an active exception

How to reproduce that error:

#include <iostream>
#include <stdlib.h>
#include <string>
#include <thread>
using namespace std;
void task1(std::string msg){
  cout << "task1 says: " << msg;
int main() { 
  std::thread t1(task1, "hello"); 
  return 0;

Compile and run:

el@defiant ~/foo4/39_threading $ g++ -o s s.cpp -pthread -std=c++11
el@defiant ~/foo4/39_threading $ ./s
terminate called without an active exception
Aborted (core dumped)

You get that error because you didn't join or detach your thread.

One way to fix it, join the thread like this:

#include <iostream>
#include <stdlib.h>
#include <string>
#include <thread>
using namespace std;
void task1(std::string msg){
  cout << "task1 says: " << msg;
int main() { 
  std::thread t1(task1, "hello"); 
  return 0;

Then compile and run:

el@defiant ~/foo4/39_threading $ g++ -o s s.cpp -pthread -std=c++11
el@defiant ~/foo4/39_threading $ ./s
task1 says: hello

The other way to fix it, detach it like this:

#include <iostream>
#include <stdlib.h>
#include <string>
#include <unistd.h>
#include <thread>
using namespace std;
void task1(std::string msg){
  cout << "task1 says: " << msg;
int main() 

        std::thread t1(task1, "hello"); 

     } //thread handle is destroyed here, as goes out of scope!

     usleep(1000000); //wait so that hello can be printed.

Compile and run:

el@defiant ~/foo4/39_threading $ g++ -o s s.cpp -pthread -std=c++11
el@defiant ~/foo4/39_threading $ ./s
task1 says: hello

Read up on detaching C++ threads and joining C++ threads.

Using FileUtils in eclipse

Open the project's properties---> Java Build Path ---> Libraries tab ---> Add External Jars

will allow you to add jars.

You need to download commonsIO from here.

CSS strikethrough different color from text?

Yes, by adding an extra wrapping element. Assign the desired line-through color to an outer element, then the desired text color to the inner element. For example:

<span style='color:red;text-decoration:line-through'>_x000D_
  <span style='color:black'>black with red strikethrough</span>_x000D_


<strike style='color:red'>_x000D_
  <span style='color:black'>black with red strikethrough<span>_x000D_

(Note, however, that <strike> is considered deprecated in HTML4 and obsolete in HTML5 (see also The recommended approach is to use <del> if a true meaning of deletion is intended, or otherwise to use an <s> element or style with text-decoration CSS as in the first example here.)

To make the strikethrough appear for a:hover, an explicit stylesheet (declared or referenced in <HEAD>) must be used. (The :hover pseudo-class can't be applied with inline STYLE attributes.) For example:

    a.redStrikeHover:hover {_x000D_
  <a href='#' class='redStrikeHover'>_x000D_
    <span style='color:black'>hover me</span>_x000D_
_x000D_ (IE7 seems to require some href be set on the <a> before :hover has an effect; FF and WebKit-based browsers do not.)

How to list the files in current directory?

You should verify that new File(".") is really pointing to where you think it is pointing - .classpath suggests the root of some Eclipse project....

How to delete directory content in Java?

To delete folder having files, no need of loops or recursive search. You can directly use:

FileUtils.deleteDirectory(<File object of directory>);

This function will directory delete the folder and all files in it.

How to change option menu icon in the action bar?

The following lines should be updated in app -> main -> res -> values -> Styles.xml

 <!-- Application theme. -->
<style name="AppTheme" parent="AppBaseTheme">
    <!-- All customizations that are NOT specific to a particular API-level can go here. -->
    <item name="android:actionOverflowButtonStyle">@style/MyActionButtonOverflow</item>

<!-- Style to replace actionbar overflow icon. set item 'android:actionOverflowButtonStyle' in AppTheme -->
<style name="MyActionButtonOverflow" parent="android:style/Widget.Holo.Light.ActionButton.Overflow">
    <item name="android:src">@drawable/ic_launcher</item>
    <item name="android:background">?android:attr/actionBarItemBackground</item>
    <item name="android:contentDescription">"Lala"</item>

This is how it can be done. If you want to change the overflow icon in action bar

How to pass a value from one jsp to another jsp page?

Use below code for passing string from one jsp to another jsp


   <% String userid="Banda";%>
    <form action="B.jsp" method="post">
    session.setAttribute("userId", userid);
        <input type="submit"


    <%String userid = session.getAttribute("userId").toString(); %>

"The system cannot find the file specified" when running C++ program

I know this is an old thread, but for any future visitors, the cause of this error is most likely because you haven't built your project from Build > Build Solution. The reason you're getting this error when you try to run your project is because Visual Studio can't find the executable file that should be produced when you build your project.

Passing A List Of Objects Into An MVC Controller Method Using jQuery Ajax

Using NickW's suggestion, I was able to get this working using things = JSON.stringify({ 'things': things }); Here is the complete code.

$(document).ready(function () {
    var things = [
        { id: 1, color: 'yellow' },
        { id: 2, color: 'blue' },
        { id: 3, color: 'red' }

    things = JSON.stringify({ 'things': things });

        contentType: 'application/json; charset=utf-8',
        dataType: 'json',
        type: 'POST',
        url: '/Home/PassThings',
        data: things,
        success: function () {          
            $('#result').html('"PassThings()" successfully called.');
        failure: function (response) {          

public void PassThings(List<Thing> things)
    var t = things;

public class Thing
    public int Id { get; set; }
    public string Color { get; set; }

There are two things I learned from this:

  1. The contentType and dataType settings are absolutely necessary in the ajax() function. It won't work if they are missing. I found this out after much trial and error.

  2. To pass in an array of objects to an MVC controller method, simply use the JSON.stringify({ 'things': things }) format.

I hope this helps someone else!

Use LINQ to get items in one List<>, that are not in another List<>

Or if you want it without negation:

var result = peopleList2.Where(p => peopleList1.All(p2 => p2.ID != p.ID));

Basically it says get all from peopleList2 where all ids in peopleList1 are different from id in peoplesList2.

Just a little bit different approach from the accepted answer :)

How can I detect if a selector returns null?

The selector returns an array of jQuery objects. If no matching elements are found, it returns an empty array. You can check the .length of the collection returned by the selector or check whether the first array element is 'undefined'.

You can use any the following examples inside an IF statement and they all produce the same result. True, if the selector found a matching element, false otherwise.

$('#notAnElement').length > 0
$('#notAnElement').get(0) !== undefined
$('#notAnElement')[0] !== undefined

ViewPager PagerAdapter not updating the View

1.First you have to set the getItemposition method in your Pageradapter class 2.You have to read the Exact position of your View Pager 3.then send that position as data location of your new one 4.Write update button onclick listener inside the setonPageChange listener

that program code is little bit i modified to set the particular position element only

public class MyActivity extends Activity {

private ViewPager myViewPager;
private List<String> data;
public int location=0;
public Button updateButton;
public void onCreate(Bundle savedInstanceState) {

    data = new ArrayList<String>();

    myViewPager = (ViewPager) findViewById(;
    myViewPager.setAdapter(new MyViewPagerAdapter(this, data));

      updateButton = (Button) findViewById(;

    myViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        public void onPageScrolled(int i, float v, int i2) {
             //Toast.makeText(MyActivity.this, i+"  Is Selected  "+data.size(), Toast.LENGTH_SHORT).show();

        public void onPageSelected( int i) {
          // here you will get the position of selected page
            final int k = i;


        public void onPageScrollStateChanged(int i) {


private void updateViewPager(final int i) {  
    updateButton.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {

            Toast.makeText(MyActivity.this, i+"  Is Selected  "+data.size(), Toast.LENGTH_SHORT).show();
            data.set(i, "Replaced "+i);         


private class MyViewPagerAdapter extends PagerAdapter {

    private List<String> data;
    private Context ctx;

    public MyViewPagerAdapter(Context ctx, List<String> data) {
        this.ctx = ctx; = data;

    public int getCount() {
        return data.size();

    public int getItemPosition(Object object) {
        return POSITION_NONE;

    public Object instantiateItem(View collection, int position) {          

        TextView view = new TextView(ctx);
        return view;

    public void destroyItem(View collection, int position, Object view) {
         ((ViewPager) collection).removeView((View) view);

    public boolean isViewFromObject(View view, Object object) {
        return view == object;

    public Parcelable saveState() {
        return null;

    public void restoreState(Parcelable arg0, ClassLoader arg1) {

    public void startUpdate(View arg0) {

    public void finishUpdate(View arg0) {

Object of custom type as dictionary key

You override __hash__ if you want special hash-semantics, and __cmp__ or __eq__ in order to make your class usable as a key. Objects who compare equal need to have the same hash value.

Python expects __hash__ to return an integer, returning Banana() is not recommended :)

User defined classes have __hash__ by default that calls id(self), as you noted.

There is some extra tips from the documentation.:

Classes which inherit a __hash__() method from a parent class but change the meaning of __cmp__() or __eq__() such that the hash value returned is no longer appropriate (e.g. by switching to a value-based concept of equality instead of the default identity based equality) can explicitly flag themselves as being unhashable by setting __hash__ = None in the class definition. Doing so means that not only will instances of the class raise an appropriate TypeError when a program attempts to retrieve their hash value, but they will also be correctly identified as unhashable when checking isinstance(obj, collections.Hashable) (unlike classes which define their own __hash__() to explicitly raise TypeError).

Disable Input fields in reactive form

name: [{value: '', disabled: true}, Validators.required],
name: [{value: '', disabled: this.isDisabled}, Validators.required],



jQuery: Uncheck other checkbox on one checked

you could use class for all your checkboxes, and do:

$(".check_class").click(function() {
  $(".check_class").attr("checked", false); //uncheck all checkboxes
  $(this).attr("checked", true);  //check the clicked one

How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly?

[Updated to adapt to modern pandas, which has isnull as a method of DataFrames..]

You can use isnull and any to build a boolean Series and use that to index into your frame:

>>> df = pd.DataFrame([range(3), [0, np.NaN, 0], [0, 0, np.NaN], range(3), range(3)])
>>> df.isnull()
       0      1      2
0  False  False  False
1  False   True  False
2  False  False   True
3  False  False  False
4  False  False  False
>>> df.isnull().any(axis=1)
0    False
1     True
2     True
3    False
4    False
dtype: bool
>>> df[df.isnull().any(axis=1)]
   0   1   2
1  0 NaN   0
2  0   0 NaN

[For older pandas:]

You could use the function isnull instead of the method:

In [56]: df = pd.DataFrame([range(3), [0, np.NaN, 0], [0, 0, np.NaN], range(3), range(3)])

In [57]: df
   0   1   2
0  0   1   2
1  0 NaN   0
2  0   0 NaN
3  0   1   2
4  0   1   2

In [58]: pd.isnull(df)
       0      1      2
0  False  False  False
1  False   True  False
2  False  False   True
3  False  False  False
4  False  False  False

In [59]: pd.isnull(df).any(axis=1)
0    False
1     True
2     True
3    False
4    False

leading to the rather compact:

In [60]: df[pd.isnull(df).any(axis=1)]
   0   1   2
1  0 NaN   0
2  0   0 NaN

Cannot retrieve string(s) from preferences (settings)

All your exercise conditionals are separate and the else is only tied to the last if statement. Use else if to bind them all together in the way I believe you intend.

Adding 1 hour to time variable

$time = '10:09';
$timestamp = strtotime($time);
$timestamp_one_hour_later = $timestamp + 3600; // 3600 sec. = 1 hour

// Formats the timestamp to HH:MM => outputs 11:09.
echo strftime('%H:%M', $timestamp_one_hour_later);
// As crolpa suggested, you can also do
// echo date('H:i', $timestamp_one_hour_later);

Check PHP manual for strtotime(), strftime() and date() for details.

BTW, in your initial code, you need to add some quotes otherwise you will get PHP syntax errors:

$time = 10:09; // wrong syntax
$time = '10:09'; // syntax OK

$time = date(H:i, strtotime('+1 hour')); // wrong syntax
$time = date('H:i', strtotime('+1 hour')); // syntax OK

How to create radio buttons and checkbox in swift (iOS)?

A very simple checkbox control.

 @IBAction func btn_box(sender: UIButton) {
    if (btn_box.selected == true)
        btn_box.setBackgroundImage(UIImage(named: "box"), forState: UIControlState.Normal)

            btn_box.selected = false;
        btn_box.setBackgroundImage(UIImage(named: "checkBox"), forState: UIControlState.Normal)

        btn_box.selected = true;

How to import an existing directory into Eclipse?

The Eclipse UI is a little bit confusing.

The Import -> "Existing projects into workspace" actually means import "Existing Eclipse projects into workspace". That's why you can't click on finish: the import option looks for a .project file (the file used by Eclipse to store the project options) in the directory that you have chosen.

To import existing source code that doesn't have an Eclipse project file you have the following options (I suppose that you want to create a Java project):

  1. New project inside the workspace dir: Create a new empty Java project into the workspace (File->New->Java Project). Then right click on the source folder and choose Import...->General->File system then choose your files, and it will make a copy of your files.

    Tip: you can drag&drop your files from the Finder into the src folder.

  2. Create an eclipse project in your existing dir: Create a new Java project, but in the "New Java Project" window:

    • Un check the Use default location option, and choose the directory where is your non-Eclipse project.
    • Click Next and configure the sub-directories of your non-Eclipse project where the source files are located. And you are done :)

How do I keep Python print from adding newlines or spaces?

This may look stupid, but seems to be the simplest:

    print 'h',
    print '\bm'

Word-wrap in an HTML table

It appears you need to set word-wrap:break-word; on a block element (div), with specified (non relative) width. Ex:

<table style="width: 100%;"><tr>_x000D_
    <td><div style="display:block; word-wrap: break-word; width: 40em;">loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong word</div></td>_x000D_
    <td><span style="display: inline;">Foo</span></td>_x000D_

or using word-break:break-all per Abhishek Simon's suggestion.

Convert JsonNode into POJO

In Jackson 2.4, you can convert as follows:

MyClass newJsonNode = jsonObjectMapper.treeToValue(someJsonNode, MyClass.class);

where jsonObjectMapper is a Jackson ObjectMapper.

In older versions of Jackson, it would be

MyClass newJsonNode = jsonObjectMapper.readValue(someJsonNode, MyClass.class);

vba error handling in loop

What about?

If oSheet.QueryTables.Count > 0 Then
  oCmbBox.AddItem oSheet.Name
End If 


If oSheet.ListObjects.Count > 0 Then
    '// Source type 3 = xlSrcQuery
    If oSheet.ListObjects(1).SourceType = 3 Then
         oCmbBox.AddItem oSheet.Name
    End IF
End IF

Handling urllib2's timeout? - Python

There are very few cases where you want to use except:. Doing this captures any exception, which can be hard to debug, and it captures exceptions including SystemExit and KeyboardInterupt, which can make your program annoying to use..

At the very simplest, you would catch urllib2.URLError:

    urllib2.urlopen("", timeout = 1)
except urllib2.URLError, e:
    raise MyException("There was an error: %r" % e)

The following should capture the specific error raised when the connection times out:

import urllib2
import socket

class MyException(Exception):

    urllib2.urlopen("", timeout = 1)
except urllib2.URLError, e:
    # For Python 2.6
    if isinstance(e.reason, socket.timeout):
        raise MyException("There was an error: %r" % e)
        # reraise the original error
except socket.timeout, e:
    # For Python 2.7
    raise MyException("There was an error: %r" % e)

Post multipart request with Android SDK

Remove all your httpclient, httpmime dependency and add this dependency compile 'commons-httpclient:commons-httpclient:3.1'. This dependency has built in MultipartRequestEntity so that you can easily upload one or more files to the server

public class FileUploadUrlConnection extends AsyncTask<String, String, String> {
private Context context;
private String url;
private List<File> files;

public FileUploadUrlConnection(Context context, String url, List<File> files) {
    this.context = context;
    this.url = url;
    this.files = files;

protected String doInBackground(String... params) {

    HttpClient client = new HttpClient();
    PostMethod post = new PostMethod(url);
    HttpClientParams connectionParams = new HttpClientParams();

    post.setRequestHeader(// Your header goes here );

    try {
        Part[] parts = new Part[files.size()];
        for (int i=0; i<files.size(); i++) {
            Part part = new FilePart(files.get(i).getName(), files.get(i));
            parts[i] = part;

        MultipartRequestEntity entity = new MultipartRequestEntity(parts, connectionParams);


        int statusCode = client.executeMethod(post);
        String response = post.getResponseBodyAsString();

        Log.v("Multipart "," "+response);
        if(statusCode == 200) {
            return response;
    } catch (IOException e) {
 return null;

You can also add the request and response timeout

client.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 10000);
client.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, 10000);

Check if a div exists with jquery

As karim79 mentioned, the first is the most concise. However I could argue that the second is more understandable as it is not obvious/known to some Javascript/jQuery programmers that non-zero/false values are evaluated to true in if-statements. And because of that, the third method is incorrect.

await vs Task.Wait - Deadlock?

Based on what I read from different sources:

An await expression does not block the thread on which it is executing. Instead, it causes the compiler to sign up the rest of the async method as a continuation on the awaited task. Control then returns to the caller of the async method. When the task completes, it invokes its continuation, and execution of the async method resumes where it left off.

To wait for a single task to complete, you can call its Task.Wait method. A call to the Wait method blocks the calling thread until the single class instance has completed execution. The parameterless Wait() method is used to wait unconditionally until a task completes. The task simulates work by calling the Thread.Sleep method to sleep for two seconds.

This article is also a good read.

How to upgrade PostgreSQL from version 9.6 to version 10.1 without losing data?

Looks like the solution has been baked into Homebrew now:

$ brew info postgresql
==> Caveats
To migrate existing data from a previous major version of PostgreSQL run:
  brew postgresql-upgrade-database

Uncaught SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode

This means that you must declare strict mode by writing "use strict" at the beginning of the file or the function to use block-scope declarations.


function test(){
    "use strict";
    let a = 1;

Markdown `native` text alignment

It's hacky but if you're using GFM or some other MD syntax which supports building tables with pipes you can use the column alignment features:

|| <!-- empty table header -->
|:--:| <!-- table header/body separator with center formatting -->
| I'm centered! | <!-- cell gets column's alignment -->

This works in marked.

Counting lines, words, and characters within a text file using Python

Functions that might be helpful:

  • open("file").read() which reads the contents of the whole file at once
  • 'string'.splitlines() which separates lines from each other (and discards empty lines)

By using len() and those functions you could accomplish what you're doing.

How to increase the timeout period of web service in

1 - You can set a timeout in your application :

var client = new YourServiceReference.YourServiceClass();
client.Timeout = 60; // or -1 for infinite

It is in milliseconds.

2 - Also you can increase timeout value in httpruntime tag in web/app.config :

          <httpRuntime executionTimeout="<<**seconds**>>" />

For ASP.NET applications, the Timeout property value should always be less than the executionTimeout attribute of the httpRuntime element in Machine.config. The default value of executionTimeout is 90 seconds. This property determines the time ASP.NET continues to process the request before it returns a timed out error. The value of executionTimeout should be the proxy Timeout, plus processing time for the page, plus buffer time for queues. -- Source

INSERT INTO from two different server database

You cannot directly copy a table into a destination server database from a different database if source db is not in your linked servers. But one way is possible that, generate scripts (schema with data) of the desired table into one table temporarily in the source server DB, then execute the script in the destination server DB to create a table with your data. Finally use INSERT INTO [DESTINATION_TABLE] select * from [TEMPORARY_SOURCE_TABLE]. After getting the data into your destination table drop the temporary one.

I found this solution when I faced the same situation. Hope this helps you too.

sql query to get earliest date

SELECT TOP 1 ID, Name, Score, [Date]
FROM myTable
Order BY [Date]

How to write asynchronous functions for Node.js

I've dealing too many hours for such task in for node.js. I'm mainly front-end guy.

I find this quite important, because all node methods asyncronous deal with callback, and transform it into Promise is better to handle it.

I Just want to show a possible outcome, more lean and readable. Using ECMA-6 with async you can write it like this.

 async function getNameFiles (dirname) {
  return new Promise((resolve, reject) => {
    fs.readdir(dirname, (err, filenames) => {
      err !== (undefined || null) ? reject(err) : resolve(filenames)

the (undefined || null) is for repl (read event print loop) scenarios, using undefined also work.

How to execute a .bat file from a C# windows form app?

Here is what you are looking for:

Service hangs up at WaitForExit after calling batch file

It's about a question as to why a service can't execute a file, but it shows all the code necessary to do so.

html <input type="text" /> onchange event not working

onchange is only triggered when the control is blurred. Try onkeypress instead.

How to download PDF automatically using js?

  1. for second point, get a full path to pdf file into some java variable. e.g.

e.g. you're using php and $filepath contains pdf file path.

so you can write javascript like to to emulate download dialog box.

<script language="javascript">
    window.location.href = '<?php echo $filepath; ?>';

Above code sends browser to pdf file by its url "". So at last, browser will show download dialog box to where to save this file on your machine.

Xml serialization - Hide null values

I prefer creating my own xml with no auto-generated tags. In this I can ignore creating the nodes with null values:

public static string ConvertToXML<T>(T objectToConvert)
        XmlDocument doc = new XmlDocument();
        XmlNode root = doc.CreateNode(XmlNodeType.Element, objectToConvert.GetType().Name, string.Empty);
        XmlNode childNode;

        PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
        foreach (PropertyDescriptor prop in properties)
            if (prop.GetValue(objectToConvert) != null)
                childNode = doc.CreateNode(XmlNodeType.Element, prop.Name, string.Empty);
                childNode.InnerText = prop.GetValue(objectToConvert).ToString();

        return doc.OuterXml;

Securely storing passwords for use in python script

Know the master key yourself. Don't hard code it.

Use py-bcrypt (bcrypt), powerful hashing technique to generate a password yourself.

Basically you can do this (an idea...)

import bcrypt
from getpass import getpass
master_secret_key = getpass('tell me the master secret key you are going to use')
salt = bcrypt.gensalt()
combo_password = raw_password + salt + master_secret_key
hashed_password = bcrypt.hashpw(combo_password, salt)

save salt and hashed password somewhere so whenever you need to use the password, you are reading the encrypted password, and test against the raw password you are entering again.

This is basically how login should work these days.

To delay JavaScript function call using jQuery

Since you declare sample inside the anonymous function you pass to ready, it is scoped to that function.

You then pass a string to setTimeout which is evaled after 2 seconds. This takes place outside the current scope, so it can't find the function.

Only pass functions to setTimeout, using eval is inefficient and hard to debug.


Convert `List<string>` to comma-separated string

The following will result in a comma separated list. Be sure to include a using statement for System.Linq

List<string> ls = new List<string>();
string type = ls.Aggregate((x,y) => x + "," + y);

will yield one,two

if you need a space after the comma, simply change the last line to string type = ls.Aggregate((x,y) => x + ", " + y);

Command not found error in Bash variable assignment

I know this has been answered with a very high-quality answer. But, in short, you cant have spaces.

STR = "Hello World"
echo $STR

Didn't work because of the spaces around the equal sign. If you were to run...

STR="Hello World"
echo $STR

It would work

Freely convert between List<T> and IEnumerable<T>

A List<T> is already an IEnumerable<T>, so you can run LINQ statements directly on your List<T> variable.

If you don't see the LINQ extension methods like OrderBy() I'm guessing it's because you don't have a using System.Linq directive in your source file.

You do need to convert the LINQ expression result back to a List<T> explicitly, though:

List<Customer> list = ...
list = list.OrderBy(customer => customer.Name).ToList()

laravel compact() and ->with()

Route::get('/', function () {
    return view('greeting', ['name' => 'James']);
        <h1>Hello, {{ $name }}</h1>


public function index($id)
    $category = Category::find($id);
    $topics = $category->getTopicPaginator();
    $message = Message::find(1);

    // here I would just use "->with([$category, $topics, $message])"
    return View::make('category.index')->with(compact('category', 'topics', 'message'));

Last executed queries for a specific database

This works for me to find queries on any database in the instance. I'm sysadmin on the instance (check your privileges):

SELECT deqs.last_execution_time AS [Time], dest.text AS [Query], dest.*
FROM sys.dm_exec_query_stats AS deqs
CROSS APPLY sys.dm_exec_sql_text(deqs.sql_handle) AS dest
WHERE dest.dbid = DB_ID('msdb')
ORDER BY deqs.last_execution_time DESC

This is the same answer that Aaron Bertrand provided but it wasn't placed in an answer.

What is the equivalent of bigint in C#?

I was handling a bigint datatype to be shown in a DataGridView and made it like this

something = (int)(Int64)data_reader[0];

Making PHP var_dump() values display one line per value

Use output buffers:

    var_dump($_SERVER) ;
    $dump = ob_get_contents();

    echo "<pre> $dump </pre>";

Yet another option would be to use Output buffering and convert all the newlines in the dump to <br> elements, e.g.

var_dump($_SERVER) ;
echo nl2br(ob_get_clean());

What's the UIScrollView contentInset property for?

It sets the distance of the inset between the content view and the enclosing scroll view.


aScrollView.contentInset = UIEdgeInsetsMake(0, 0, 0, 7.0);

Swift 5.0

aScrollView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 7.0)

Here's a good iOS Reference Library article on scroll views that has an informative screenshot (fig 1-3) - I'll replicate it via text here:

   |       | 
   |content| ?
 ? |content|
cH |content|
 ? |content| contentInset.bottom
   |content| ?

   (cH = contentSize.height; cW = contentSize.width)

The scroll view encloses the content view plus whatever padding is provided by the specified content insets.

How to change maven logging level to display only warning and errors?

I have noticed when using the 2.20.1 version of the maven sunfire plugin, all warnings are written down to a dumpstream file. e.g. /myproject/target/surefire-reports/2017-11-11T23-02-19_850.dumpstream

Creating multiple objects with different names in a loop to store in an array list

ArrayList<Customer> custArr = new ArrayList<Customer>();
while(youWantToContinue) {
    //get a customerName
    //get an amount
    custArr.add(new Customer(customerName, amount);

For this to work... you'll have to fix your constructor...

Assuming your Customer class has variables called name and sale, your constructor should look like this:

public Customer(String customerName, double amount) {
    name = customerName;
    sale = amount;

Change your Store class to something more like this:

public class Store {

    private ArrayList<Customer> custArr;

    public new Store() {
        custArr = new ArrayList<Customer>();

    public void addSale(String customerName, double amount) {
        custArr.add(new Customer(customerName, amount));

    public Customer getSaleAtIndex(int index) {
        return custArr.get(index);

    //or if you want the entire ArrayList:
    public ArrayList getCustArr() {
        return custArr;

HTML/CSS font color vs span style

1st preference external style sheet.

<span class="myClass">test</span>



2nd preference inline style

<span style="color:red">test</span>

<font> as mentioned is deprecated.

Force uninstall of Visual Studio

So Soumyaansh's Revo Uninstaller Pro fix worked for me :) ( After 2 days of troubleshooting other options {screams internally 😀} ).

I did run into the an issue with his method though, "Could not find a suitable SDK to target" even though I selected to install Visual Studio with custom settings and selected the SDK I wanted to install. You may need to download the Windows 10 Standalone SDK to resolved this, in order to develop UWP apps if you see this same error after reinstalling Visual Studio.

To do this

  1. Uninstall any Windows 10 SDKs that me on the system (the naming schem for them looks like Windows 10 SDK (WINDOWS_VERSION_NUMBER_HERE) -> Windows 10 SDK (14393) etc . . .). If there are no SDKs on your system go to step 2!
  2. All that's left is to download the SDKs you want by Checking out the SDK Archive for all available SDKs and you should be good to go in developing for the UWP!

C++11 reverse range-based for-loop

Got this example from cppreference. It works with:

GCC 10.1+ with flag -std=c++20

#include <ranges>
#include <iostream>
int main()
    static constexpr auto il = {3, 1, 4, 1, 5, 9};
    std::ranges::reverse_view rv {il};
    for (int i : rv)
        std::cout << i << ' ';
    std::cout << '\n';
    for(int i : il | std::views::reverse)
        std::cout << i << ' ';

How can I convert byte size into a human-readable format in Java?

String[] fileSizeUnits = {"bytes", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"};

public String calculateProperFileSize(double bytes){
    String sizeToReturn = "";
    int index = 0;
    for(index = 0; index < fileSizeUnits.length; index++){
        if(bytes < 1024){
        bytes = bytes / 1024;

    System.out.println("File size in proper format: " + bytes + " " + fileSizeUnits[index]);
    sizeToReturn = String.valueOf(bytes) + " " + fileSizeUnits[index];
    return sizeToReturn;

Just add more file units (if any missing), and you will see unit size up to that unit (if your file has that much length):

OpenCV with Network Cameras

OpenCV can be compiled with FFMPEG support. From ./configure --help:

--with-ffmpeg     use ffmpeg libraries (see LICENSE) [automatic]

You can then use cvCreateFileCapture_FFMPEG to create a CvCapture with e.g. the URL of the camera's MJPG stream.

I use this to grab frames from an AXIS camera:

CvCapture *capture = 

syntax error near unexpected token `('


sudo -su db2inst1 /opt/ibm/db2/V9.7/bin/db2 force application \(1995\)

Check if a given key already exists in a dictionary and increment it

Here's one-liner that I came up with recently for solving this problem. It's based on the setdefault dictionary method:

my_dict = {}
my_dict[key] = my_dict.setdefault(key, 0) + 1

Visual Studio opens the default browser instead of Internet Explorer

Right-click on an aspx file and choose 'browse with'. I think there's an option there to set as default.

How do I expire a PHP session after 30 minutes?

Just Store the current time and If it exceeds 30 minutes by comparing then destroy the current session.

How to prevent a background process from being stopped after closing SSH client in Linux

On systemd/Linux, systemd-run is a nice tool to launch session-independent processes.

What is the problem with shadowing names defined in outer scopes?

I like to see a green tick in the top right corner in PyCharm. I append the variable names with an underscore just to clear this warning so I can focus on the important warnings.

data = [4, 5, 6]

def print_data(data_):


Getting Database connection in pure JPA setup

if you use EclipseLink: You should be in a JPA transaction to access the Connection

java.sql.Connection connection = entityManager.unwrap(java.sql.Connection.class);

How to display special characters in PHP

So I try htmlspecialchars() or htmlentities() which outputs <p>Résumé<p> and the browser renders <p>Résumé<p>.

If you've got it working where it displays Résumé with <p></p> tags around it, then just don't convert the paragraph, only your string. Then the paragraph will be rendered as HTML and your string will be displayed within.

Python 3 print without parenthesis

The AHK script is a great idea. Just for those interested I needed to change it a little bit to work for me:

SetTitleMatchMode,2         ;;; allows for a partial search 
#IfWinActive, .py           ;;; scope limiter to only python files
:b*:print ::print(){Left}   ;;; I forget what b* does
#IfWinActive                ;;; remove the scope limitation

Copy/Paste/Calculate Visible Cells from One Column of a Filtered Table

I set up a simple 3-column range on Sheet1 with Country, City, and Language in columns A, B, and C. The following code autofilters the range and then pastes only one of the columns of autofiltered data to another sheet. You should be able to modify this for your purposes:

Sub CopyPartOfFilteredRange()
    Dim src As Worksheet
    Dim tgt As Worksheet
    Dim filterRange As Range
    Dim copyRange As Range
    Dim lastRow As Long

    Set src = ThisWorkbook.Sheets("Sheet1")
    Set tgt = ThisWorkbook.Sheets("Sheet2")

    ' turn off any autofilters that are already set
    src.AutoFilterMode = False

    ' find the last row with data in column A
    lastRow = src.Range("A" & src.Rows.Count).End(xlUp).Row

    ' the range that we are auto-filtering (all columns)
    Set filterRange = src.Range("A1:C" & lastRow)

    ' the range we want to copy (only columns we want to copy)
    ' in this case we are copying country from column A
    ' we set the range to start in row 2 to prevent copying the header
    Set copyRange = src.Range("A2:A" & lastRow)

    ' filter range based on column B
    filterRange.AutoFilter field:=2, Criteria1:="Rio de Janeiro"

    ' copy the visible cells to our target range
    ' note that you can easily find the last populated row on this sheet
    ' if you don't want to over-write your previous results
    copyRange.SpecialCells(xlCellTypeVisible).Copy tgt.Range("A1")

End Sub

Note that by using the syntax above to copy and paste, nothing is selected or activated (which you should always avoid in Excel VBA) and the clipboard is not used. As a result, Application.CutCopyMode = False is not necessary.

How to make certain text not selectable with CSS

The CSS below stops users from being able to select text.

-webkit-user-select: none; /* Safari */        
-moz-user-select: none; /* Firefox */
-ms-user-select: none; /* IE10+/Edge */
user-select: none; /* Standard */

To target IE9 downwards the html attribute unselectable must be used instead:

<p unselectable="on">Test Text</p>

How to check Elasticsearch cluster health?

The _cluster/health API can do far more than the typical output that most see with it:

 $ curl -XGET 'localhost:9200/_cluster/health?pretty'

Most APIs within Elasticsearch can take a variety of arguments to augment their output. This applies to Cluster Health API as well.


all the indices health
$ curl -XGET 'localhost:9200/_cluster/health?level=indices&pretty' | head -50
  "cluster_name" : "rdu-es-01",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 9,
  "number_of_data_nodes" : 6,
  "active_primary_shards" : 1106,
  "active_shards" : 2213,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 100.0,
  "indices" : {
    "filebeat-6.5.1-2019.06.10" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    "filebeat-6.5.1-2019.06.11" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    "filebeat-6.5.1-2019.06.12" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    "filebeat-6.5.1-2019.06.13" : {
      "status" : "green",
      "number_of_shards" : 3,
all shards health
$ curl -XGET 'localhost:9200/_cluster/health?level=shards&pretty' | head -50
  "cluster_name" : "rdu-es-01",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 9,
  "number_of_data_nodes" : 6,
  "active_primary_shards" : 1106,
  "active_shards" : 2213,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 100.0,
  "indices" : {
    "filebeat-6.5.1-2019.06.10" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0,
      "shards" : {
        "0" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0
        "1" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0
        "2" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0

The API also has a variety of wait_* options where it'll wait for various state changes before returning immediately or after some specified timeout.

Run as java application option disabled in eclipse

I had this same problem. For me, the reason turned out to be that I had a mismatch in the name of the class and the name of the file. I declared class "GenSig" in a file called "".

I changed the name of the class to "SignatureTester", and the "Run as Java Application" option showed up immediately.

openpyxl - adjust column width size

Even more pythonic way to set the width of all columns that works at least in openpyxl version 2.4.0:

for column_cells in worksheet.columns:
    length = max(len(as_text(cell.value)) for cell in column_cells)
    worksheet.column_dimensions[column_cells[0].column].width = length

The as_text function should be something that converts the value to a proper length string, like for Python 3:

def as_text(value):
    if value is None:
        return ""
    return str(value)

SQL Error: ORA-12899: value too large for column

As mentioned, the error message shows you the exact problem: you are passing 25 characters into a field set up to hold 20. You might also want to consider defining the columns a little more precisely. You can define whether the VARCHAR2 column will store a certain number of bytes or characters. You may encounter a problem in the future where you try to insert a multi byte character into the field, for example this is 5 characters in length but it won't fit into 5 bytes: 'ÀÈÌÕÛ'

Here is an example:

CREATE TABLE Customers(CustomerID  VARCHAR2(9 BYTE), ...


CREATE TABLE Customers(CustomerID  VARCHAR2(9 CHAR), ...

How to list all available Kafka brokers in a cluster?

Here are a couple of quick functions I use when bash scripting Kafka Data Load into Demo Environments. In this example I use HDP with no security, but it is easily modified to other environments and intended to be quick and functional rather than particularly robust.

The first retrieves the address of the first ZooKeeper node from the config:

ZKS1=$(cat /usr/hdp/current/zookeeper-client/conf/zoo.cfg | grep server.1)
[[ ${ZKS1} =~ server.1=(.*?):[0-9]*:[0-9]* ]]
export ZKADDR=${BASH_REMATCH[1]}:2181
echo "using ZooKeeper Server $ZKADDR"

The second retrieves the Broker IDs from ZooKeeper:

echo "Fetching list of Kafka Brokers"
export BROKERIDS=$(/usr/hdp/current/kafka-broker/bin/ ${ZKADDR} <<< 'ls /brokers/ids' | tail -1)
export BROKERIDS=${BROKERIDS//[!0-9 ]/}
echo "Found Kafka Broker IDS: $BROKERIDS"

The third parses ZooKeeper again to retrieve the list of Kafka Brokers Host:port ready for use in the command-line client:

for i in $BROKERIDS
DETAIL=$(/usr/hdp/current/kafka-broker/bin/ ${ZKADDR} <<< "get /brokers/ids/$i")
[[ $DETAIL =~ PLAINTEXT:\/\/(.*?)\"\] ]]
if [ -z ${BROKERS+x} ]; then BROKERS=${BASH_REMATCH[1]}; else 
echo "Found Brokerlist: $BROKERS"

Retrieving the first digit of a number

int firstDigit = Integer.parseInt(Character.toString(firstLetterChar));

Convert NSDate to NSString

Define your own utility for format your date required date format for eg.

NSString * stringFromDate(NSDate *date)  
 {   NSDateFormatter *formatter
    [[NSDateFormatter alloc] init];  
    [formatter setDateFormat:@"MM / dd / yyyy, hh?mm a"];    
    return [formatter stringFromDate:date]; 

How to get terminal's Character Encoding

To my knowledge, no.

Circumstantial indications from $LC_CTYPE, locale and such might seem alluring, but these are completely separated from the encoding the terminal application (actually an emulator) happens to be using when displaying characters on the screen.

They only way to detect encoding for sure is to output something only present in the encoding, e.g. ä, take a screenshot, analyze that image and check if the output character is correct.

So no, it's not possible, sadly.

SQL, How to convert VARCHAR to bigint?

an alternative would be to do something like:

   CAST(P0.seconds as bigint) as seconds
      ISNUMERIC(seconds) = 1
   ) P0

How to redirect output of an already running process


Dupx is a simple *nix utility to redirect standard output/input/error of an already running process.


I've often found myself in a situation where a process I started on a remote system via SSH takes much longer than I had anticipated. I need to break the SSH connection, but if I do so, the process will die if it tries to write something on stdout/error of a broken pipe. I wish I could suspend the process with ^Z and then do a

bg %1 >/tmp/stdout 2>/tmp/stderr 

Unfortunately this will not work (in shells I know).

Undefined reference to static class member

The C++ standard requires a definition for your static const member if the definition is somehow needed.

The definition is required, for example if it's address is used. push_back takes its parameter by const reference, and so strictly the compiler needs the address of your member and you need to define it in the namespace.

When you explicitly cast the constant, you're creating a temporary and it's this temporary which is bound to the reference (under special rules in the standard).

This is a really interesting case, and I actually think it's worth raising an issue so that the std be changed to have the same behaviour for your constant member!

Although, in a weird kind of way this could be seen as a legitimate use of the unary '+' operator. Basically the result of the unary + is an rvalue and so the rules for binding of rvalues to const references apply and we don't use the address of our static const member:

v.push_back( +Foo::MEMBER );

How to convert URL parameters to a JavaScript object?

 * Parses and builds Object of URL query string.
 * @param {string} query The URL query string.
 * @return {!Object<string, string>}
function parseQueryString(query) {
  if (!query) {
    return {};
  return (/^[?#]/.test(query) ? query.slice(1) : query)
      .reduce((params, param) => {
        const item = param.split('=');
        const key = decodeURIComponent(item[0] || '');
        const value = decodeURIComponent(item[1] || '');
        if (key) {
          params[key] = value;
        return params;
      }, {});

see log

Sorting arrays in NumPy by column

I suppose this works: a[a[:,1].argsort()]

This indicates the second column of a and sort it based on it accordingly.

To check if string contains particular word

You can use regular expressions:

if (d.matches(".*Hey.*")) {
    c.setText("OUTPUT: SUCCESS!");
} else {
    c.setText("OUTPUT: FAIL!");  

.* -> 0 or more of any characters

Hey -> The string you want

If you will be checking this often, it is better to compile the regular expression in a Pattern object and reuse the Pattern instance to do the checking.

private static final Pattern HEYPATTERN = Pattern.compile(".*Hey.*");
if (HEYPATTERN.matcher(d).matches()) {
    c.setText("OUTPUT: SUCCESS!");
} else {
    c.setText("OUTPUT: FAIL!");  

Just note this will also match "Heyburg" for example since you didn't specify you're searching for "Hey" as an independent word. If you only want to match Hey as a word, you need to change the regex to .*\\bHey\\b.*

How to find the index of an element in an array in Java?

Alternatively, you can use Commons Lang ArrayUtils class:

int[] arr = new int{3, 5, 1, 4, 2};
int indexOfTwo = ArrayUtils.indexOf(arr, 2);

There are overloaded variants of indexOf() method for different array types.

How can I call PHP functions by JavaScript?

Void Function

function printMessage() {
    echo "Hello World!";

    document.write("<?php printMessage() ?>");

Value Returning Function

function getMessage() {
    return "Hello World!";

    var text = "<?php echo getMessage() ?>";

Convert date to day name e.g. Mon, Tue, Wed

Very Simply Short week day name with Month and year

echo date('D, d-M-y');


Tue, 16-Feb-21

as per my requirements

return $item->start_time->format("D, d-M");


Tue, 16-Feb

R: += (plus equals) and ++ (plus plus) equivalent from c++/c#/java, etc.?

R doesn't have these operations because (most) objects in R are immutable. They do not change. Typically, when it looks like you're modifying an object, you're actually modifying a copy.

What is the difference between % and %% in a cmd file?

(Explanation in more details can be found in an archived Microsoft KB article.)

Three things to know:

  1. The percent sign is used in batch files to represent command line parameters: %1, %2, ...
  2. Two percent signs with any characters in between them are interpreted as a variable:

    echo %myvar%

  3. Two percent signs without anything in between (in a batch file) are treated like a single percent sign in a command (not a batch file): %%f

Why's that?

For example, if we execute your (simplified) command line

FOR /f %f in ('dir /b .') DO somecommand %f

in a batch file, rule 2 would try to interpret

%f in ('dir /b .') DO somecommand %

as a variable. In order to prevent that, you have to apply rule 3 and escape the % with an second %:

FOR /f %%f in ('dir /b .') DO somecommand %%f

HTML table with horizontal scrolling (first column fixed)

Based on skube's approach, I found the minimal set of CSS I needed was:

.horizontal-scroll-except-first-column {_x000D_
  width: 100%;_x000D_
  overflow: auto;_x000D_
.horizontal-scroll-except-first-column > table {_x000D_
  margin-left: 8em;_x000D_
.horizontal-scroll-except-first-column > table > * > tr > th:first-child,_x000D_
.horizontal-scroll-except-first-column > table > * > tr > td:first-child {_x000D_
  position: absolute;_x000D_
  width: 8em;_x000D_
  margin-left: -8em;_x000D_
  background: #ccc;_x000D_
.horizontal-scroll-except-first-column > table > * > tr > th,_x000D_
.horizontal-scroll-except-first-column > table > * > tr > td {_x000D_
  /* Without this, if a cell wraps onto two lines, the first column_x000D_
   * will look bad, and may need padding. */_x000D_
  white-space: nowrap;_x000D_
<div class="horizontal-scroll-except-first-column">_x000D_
        <td>FIXED</td> <td>22222</td> <td>33333</td> <td>44444</td> <td>55555</td> <td>66666</td> <td>77777</td> <td>88888</td> <td>99999</td> <td>AAAAA</td> <td>BBBBB</td> <td>CCCCC</td> <td>DDDDD</td> <td>EEEEE</td> <td>FFFFF</td>_x000D_

How to condense if/else into one line in Python?

There is the conditional expression:

a if cond else b

but this is an expression, not a statement.

In if statements, the if (or elif or else) can be written on the same line as the body of the block if the block is just one like:

if something: somefunc()
else: otherfunc()

but this is discouraged as a matter of formatting-style.

How to check if a string contains an element from a list in Python

Use a generator together with any, which short-circuits on the first True:

if any(ext in url_string for ext in extensionsToCheck):

EDIT: I see this answer has been accepted by OP. Though my solution may be "good enough" solution to his particular problem, and is a good general way to check if any strings in a list are found in another string, keep in mind that this is all that this solution does. It does not care WHERE the string is found e.g. in the ending of the string. If this is important, as is often the case with urls, you should look to the answer of @Wladimir Palant, or you risk getting false positives.

What is the strict aliasing rule?

Strict aliasing is not allowing different pointer types to the same data.

This article should help you understand the issue in full detail.

Convert a matrix to a 1 dimensional array

Either read it in with 'scan', or just do as.vector() on the matrix. You might want to transpose the matrix first if you want it by rows or columns.

> m=matrix(1:12,3,4)
> m
     [,1] [,2] [,3] [,4]
[1,]    1    4    7   10
[2,]    2    5    8   11
[3,]    3    6    9   12
> as.vector(m)
 [1]  1  2  3  4  5  6  7  8  9 10 11 12
> as.vector(t(m))
 [1]  1  4  7 10  2  5  8 11  3  6  9 12

VBA - If a cell in column A is not blank the column B equals

Another way (Using Formulas in VBA). I guess this is the shortest VBA code as well?

Sub Sample()
    Dim ws As Worksheet
    Dim lRow As Long

    Set ws = ThisWorkbook.Sheets("Sheet1")

    With ws
        lRow = .Range("A" & .Rows.Count).End(xlUp).Row

        .Range("B1:B" & lRow).Formula = "=If(A1<>"""",""My Text"","""")"
        .Range("B1:B" & lRow).Value = .Range("B1:B" & lRow).Value
    End With
End Sub

How to display length of filtered ng-repeat data

It is also useful to note that you can store multiple levels of results by grouping filters

all items: {{items.length}}
filtered items: {{filteredItems.length}}
limited and filtered items: {{limitedAndFilteredItems.length}}
<div ng-repeat="item in limitedAndFilteredItems = (filteredItems = (items | filter:search) | limitTo:25)">...</div>

here's a demo fiddle

Check if string ends with certain pattern

I tried all the different things mentioned here to get the index of the . character in a filename that ends with .[0-9][0-9]*, e.g. srcfile.1, srcfile.12, etc. Nothing worked. Finally, the following worked: int dotIndex = inputfilename.lastIndexOf(".");

Weird! This is with java -version:

openjdk version "1.8.0_131"
OpenJDK Runtime Environment (build 1.8.0_131-8u131-b11-0ubuntu1.16.10.2-b11)
OpenJDK 64-Bit Server VM (build 25.131-b11, mixed mode)

Also, the official Java doc page for regex (from which there is a quote in one of the answers above) does not seem to specify how to look for the . character. Because \., \\., and [.] did not work for me, and I don't see any other options specified apart from these.

Get total number of items on Json object?

In addition to kieran's answer, apparently, modern browsers have an Object.keys function. In this case, you could do this:


More details in this answer on How to list the properties of a javascript object

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

I'm hesitant to offer this as it misuses ye olde html. It's not a GOOD solution but it is a solution: use a table.


table.navigation {
    width: 990px;
table.navigation td {
    text-align: center;


<table cellpadding="0" cellspacing="0" border="0" class="navigation">
        <td>BASIC SERVICES</td>
        <td>SPECIALTY SERVICES</td>
        <td>OUR STAFF</td>
        <td>CONTACT US</td>

This is not what tables were created to do but until we can reliably perform the same action in a better way I guess it is just about permissable.

Rerender view on browser resize with React

@SophieAlpert is right, +1, I just want to provide a modified version of her solution, without jQuery, based on this answer.

var WindowDimensions = React.createClass({
    render: function() {
        return <span>{this.state.width} x {this.state.height}</span>;
    updateDimensions: function() {

    var w = window,
        d = document,
        documentElement = d.documentElement,
        body = d.getElementsByTagName('body')[0],
        width = w.innerWidth || documentElement.clientWidth || body.clientWidth,
        height = w.innerHeight|| documentElement.clientHeight|| body.clientHeight;

        this.setState({width: width, height: height});
        // if you are using ES2015 I'm pretty sure you can do this: this.setState({width, height});
    componentWillMount: function() {
    componentDidMount: function() {
        window.addEventListener("resize", this.updateDimensions);
    componentWillUnmount: function() {
        window.removeEventListener("resize", this.updateDimensions);

Seeding the random number generator in Javascript

No, it is not possible to seed Math.random(), but it's fairly easy to write your own generator, or better yet, use an existing one.

Check out: this related question.

Also, see David Bau's blog for more information on seeding.

MySQL: determine which database is selected?

In the comments of I found this one from ericpp %

If you just need the current database name, you can use MySQL's SELECT DATABASE() command:

function mysql_current_db() {
    $r = mysql_query("SELECT DATABASE()") or die(mysql_error());
    return mysql_result($r,0);

Difference between const reference and normal parameter

The first method passes n by value, i.e. a copy of n is sent to the function. The second one passes n by reference which basically means that a pointer to the n with which the function is called is sent to the function.

For integral types like int it doesn't make much sense to pass as a const reference since the size of the reference is usually the same as the size of the reference (the pointer). In the cases where making a copy is expensive it's usually best to pass by const reference.

Comparing strings in Java

You need both getText() - which returns an Editable and toString() - to convert that to a String for matching. So instead of: passw1.toString().equalsIgnoreCase("1234") you need passw1.getText().toString().equalsIgnoreCase("1234").

html select scroll bar

One options will be to show the selected option above (or below) the select list like following:


<div id="selText"><span>&nbsp;</span></div><br/>
<select size="4" id="mySelect" style="width:65px;color:#f98ad3;">
    <option value="1" selected>option 1 The Long Option</option>
    <option value="2">option 2</option>
    <option value="3">option 3</option>
    <option value="4">option 4</option>
    <option value="5">option 5 Another Longer than the Long Option ;)</option>
    <option value="6">option 6</option>


<script src=""   
<script type="text/javascript">
       var txt = $($(this).children("option:selected")[0]).text();
       $("<span>" + txt + "<br/></span>").appendTo($("#selText span:last"));

PS:- Set height of div#selText otherwise it will keep shifting select list downward.

How to get these two divs side-by-side?

Best that works for me:



What is the id( ) function used for?

As of in python 3 id is assigned to a value not a variable. This means that if you create two functions as below, all the three id's are the same.

>>> def xyz():
...     q=123
...     print(id(q))
>>> def iop():
...     w=123
...     print(id(w))
>>> xyz()
>>> iop()
>>> id(123)

Perform an action in every sub-directory using Bash

Handy one-liners

for D in *; do echo "$D"; done
for D in *; do find "$D" -type d; done ### Option A

find * -type d ### Option B

Option A is correct for folders with spaces in between. Also, generally faster since it doesn't print each word in a folder name as a separate entity.

# Option A
$ time for D in ./big_dir/*; do find "$D" -type d > /dev/null; done
real    0m0.327s
user    0m0.084s
sys     0m0.236s

# Option B
$ time for D in `find ./big_dir/* -type d`; do echo "$D" > /dev/null; done
real    0m0.787s
user    0m0.484s
sys     0m0.308s

Java - Abstract class to contain variables?

Sure.. Why not?
Abstract base classes are just a convenience to house behavior and data common to 2 or more classes in a single place for efficiency of storage and maintenance. Its an implementation detail.
Take care however that you are not using an abstract base class where you should be using an interface. Refer to Interface vs Base class