Programs & Examples On #Self documenting

jquery animate background position

You can also use math combination "-=" to move background

$(this).animate( {backgroundPositionX: "-=20px"} ,500);

Eclipse copy/paste entire line keyboard shortcut

On my Mac the default setting is is ALT+CMD+Down

You can change/view all key bindings by going Eclipse -> Preferences (shortcut CMD+,) and then General -> Keys

Clear ComboBox selected text

Try specifying the actual index of the item you want erase the text from and set it's Text equal to "".

myComboBox[this.SelectedIndex].Text = ""


myComboBox.selectedIndex.Text = ""

I don't remember the exact syntax but it's something along those lines.

JavaScript string encryption and decryption?

Use SimpleCrypto

Using encrypt() and decrypt()

To use SimpleCrypto, first create a SimpleCrypto instance with a secret key (password). Secret key parameter MUST be defined when creating a SimpleCrypto instance.

To encrypt and decrypt data, simply use encrypt() and decrypt() function from an instance. This will use AES-CBC encryption algorithm.

var _secretKey = "some-unique-key";

var simpleCrypto = new SimpleCrypto(_secretKey);

var plainText = "Hello World!";
var chiperText = simpleCrypto.encrypt(plainText);
console.log("Encryption process...");
console.log("Plain Text    : " + plainText);
console.log("Cipher Text   : " + cipherText);
var decipherText = simpleCrypto.decrypt(cipherText);
console.log("... and then decryption...");
console.log("Decipher Text : " + decipherText);
console.log("... done.");

DataGridView - Focus a specific cell

Set the Current Cell like:

DataGridView1.CurrentCell = DataGridView1.Rows[rowindex].Cells[columnindex]


DataGridView1.CurrentCell = DataGridView1.Item("ColumnName", 5)

and you can directly focus with Editing by:


Running a cron job at 2:30 AM everyday

crontab -e


30 2 * * * /your/command

How to Programmatically Add Views to Views

This is late but this may help someone :) :) For adding the view programmatically try like

LinearLayout rlmain = new LinearLayout(this);      
LinearLayout.LayoutParams llp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.FILL_PARENT);          
LinearLayout   ll1 = new LinearLayout (this);

ImageView iv = new ImageView(this);
LinearLayout .LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);

setContentView(rlmain, llp);

This will create your entire view programmatcally. You can add any number of view as same. Hope this may help. :)

What exactly is "exit" in PowerShell?

It's a reserved keyword (like return, filter, function, break).


Also, as per Section 7.6.4 of Bruce Payette's Powershell in Action:

But what happens when you want a script to exit from within a function defined in that script? ... To make this easier, Powershell has the exit keyword.

Of course, as other have pointed out, it's not hard to do what you want by wrapping exit in a function:

PS C:\> function ex{exit}
PS C:\> new-alias ^D ex

How to get child process from parent process

#include <sys/types.h>
#include <unistd.h>

int main()
    // Create a child process     
    int pid = fork();

    if (pid > 0)

            int j=getpid();

            printf("in parent process %d\n",j);
    // Note that pid is 0 in child process
    // and negative if fork() fails
    else if (pid == 0)

            int i=getppid();
            printf("Before sleep %d\n",i);

            int k=getppid();

            printf("in child process %d\n",k);

    return 0;


ImportError: No module named Image

On a system with both Python 2 and 3 installed and with pip2-installed Pillow failing to provide Image, it is possible to install PIL for Python 2 in a way that will solve ImportError: No module named Image:

easy_install-2.7 --user PIL


sudo easy_install-2.7 PIL

How to post JSON to PHP with curl

Jordans analysis of why the $_POST-array isn't populated is correct. However, you can use

$data = file_get_contents("php://input");

to just retrieve the http body and handle it yourself. See PHP input/output streams.

From a protocol perspective this is actually more correct, since you're not really processing http multipart form data anyway. Also, use application/json as content-type when posting your request.

Select entries between dates in doctrine 2

    EDIT: See the other answers for better solutions

The original newbie approaches that I offered were (opt1):

$qb->where("e.fecha > '" . $monday->format('Y-m-d') . "'");
$qb->andWhere("e.fecha < '" . $sunday->format('Y-m-d') . "'");

And (opt2):

$qb->add('where', "e.fecha between '2012-01-01' and '2012-10-10'");

That was quick and easy and got the original poster going immediately.

Hence the accepted answer.

As per comments, it is the wrong answer, but it's an easy mistake to make, so I'm leaving it here as a "what not to do!"

how to create a logfile in php?

To write to a log file and make a new one each day, you could use date("j.n.Y") as part of the filename.

//Something to write to txt log
$log  = "User: ".$_SERVER['REMOTE_ADDR'].' - '.date("F j, Y, g:i a").PHP_EOL.
        "Attempt: ".($result[0]['success']=='1'?'Success':'Failed').PHP_EOL.
        "User: ".$username.PHP_EOL.
//Save string to log, use FILE_APPEND to append.
file_put_contents('./log_'.date("j.n.Y").'.log', $log, FILE_APPEND);

So you would place that within your hasAccess() method.

public function hasAccess($username,$password){
    $form = array();
    $form['username'] = $username;
    $form['password'] = $password;

    $securityDAO = $this->getDAO('SecurityDAO');
    $result = $securityDAO->hasAccess($form);

    //Write action to txt log
    $log  = "User: ".$_SERVER['REMOTE_ADDR'].' - '.date("F j, Y, g:i a").PHP_EOL.
            "Attempt: ".($result[0]['success']=='1'?'Success':'Failed').PHP_EOL.
            "User: ".$username.PHP_EOL.
    file_put_contents('./log_'.date("j.n.Y").'.txt', $log, FILE_APPEND);

        $this->Session->add('user_id', $result[0]['id']);
        //$this->Session->add('username', $result[0]['username']);
        //$this->Session->add('roleid', $result[0]['roleid']);
        return $this->status(0,true,'auth.success',$result);
        return $this->status(0,false,'auth.failed',$result);

Can CSS detect the number of children an element has?

yes we can do this using nth-child like so

div:nth-child(n + 8) {
    background: red;

This will make the 8th div child onwards become red. Hope this helps...

Also, if someone ever says "hey, they can't be done with styled using css, use JS!!!" doubt them immediately. CSS is extremely flexible nowadays

Example ::

In the example the first 7 children are blue, then 8 onwards are red...

Round double value to 2 decimal places

You can use the below code to format it to two decimal places

NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];

[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setMaximumFractionDigits:2];
[formatter setRoundingMode: NSNumberFormatterRoundUp];

NSString *numberString = [formatter stringFromNumber:[NSNumber numberWithFloat:22.368511]];

NSLog(@"Result...%@",numberString);//Result 22.37

Swift 4:

let formatter = NumberFormatter()
formatter.numberStyle = .decimal
formatter.maximumFractionDigits = 2
formatter.roundingMode = .up

let str = String(describing: formatter.string(from: 12.2345)!)


How to pad zeroes to a string?

I made a function :

def PadNumber(number, n_pad, add_prefix=None):
    number_str = str(number)
    paded_number = number_str.zfill(n_pad)
    if add_prefix:
        paded_number = add_prefix+paded_number

PadNumber(99, 4)
PadNumber(1011, 8, "b'")
PadNumber('7BEF', 6, "#")

The output :


How to make a deep copy of Java ArrayList

public class Person{

    String s;
    Date d;

    public Person clone(){
        Person p = new Person();
        p.s = this.s.clone();
        p.d = this.d.clone();
        return p;

In your executing code:

ArrayList<Person> clone = new ArrayList<Person>();
for(Person p : originalList)

how to get right offset of an element? - jQuery

Just an addition to what Greg said:

$("#whatever").offset().left + $("#whatever").outerWidth()

This code will get the right position relative to the left side. If the intention was to get the right side position relative to the right (like when using the CSS right property) then an addition to the code is necessary as follows:

$("#parent_container").innerWidth() - ($("#whatever").offset().left + $("#whatever").outerWidth())

This code is useful in animations where you have to set the right side as a fixed anchor when you can't initially set the right property in CSS.

How to run a Runnable thread in Android at defined intervals?

new Handler().postDelayed(new Runnable() {
    public void run() {
        // do something...              
}, 100);

How to analyze a JMeter summary report?

A Jmeter Test Plan must have listener to showcase the result of performance test execution.

  • Listeners capture the response coming back from Server while Jmeter runs and showcase in the form of – tree, tables, graphs and log files.

  • It also allows you to save the result in a file for future reference. There are many types of listeners Jmeter provides. Some of them are: Summary Report, Aggregate Report, Aggregate Graph, View Results Tree, View Results in Table etc.

Here is the detailed understanding of each parameter in Summary report.

By referring to the figure:


Label: It is the name/URL for the specific HTTP(s) Request. If you have selected “Include group name in label?” option then the name of the Thread Group is applied as the prefix to each label.

Samples: This indicates the number of virtual users per request.

Average: It is the average time taken by all the samples to execute specific label. In our case, the average time for Label 1 is 942 milliseconds & total average time is 584 milliseconds.

Min: The shortest time taken by a sample for specific label. If we look at Min value for Label 1 then, out of 20 samples shortest response time one of the sample had was 584 milliseconds.

Max: The longest time taken by a sample for specific label. If we look at Max value for Label 1 then, out of 20 samples longest response time one of the sample had was 2867 milliseconds.

Std. Dev.: This shows the set of exceptional cases which were deviating from the average value of sample response time. The lesser this value more consistent the data. Standard deviation should be less than or equal to half of the average time for a label.

Error%: Percentage of Failed requests per Label.

Throughput: Throughput is the number of request that are processed per time unit(seconds, minutes, hours) by the server. This time is calculated from the start of first sample to the end of the last sample. Larger throughput is better.

KB/Sec: This indicates the amount of data downloaded from server during the performance test execution. In short, it is the Throughput measured in Kilobytes per second.

For more information:

Take a list of numbers and return the average

Simple math..

def average(n):
    result = 0
    for i in n:
      result += i
      ave_num = result / len(n)
    return ave_num

input -> [1,2,3,4,5]
output -> 3.0

Replace text inside td using jQuery having td containing other elements

How about:

function changeText() {
    $("#demoTable td").each(function () {
       $(this).html().replace("8: Tap on APN and Enter <B>www</B>", "");

Eclipse IDE: How to zoom in on text?

On Mac you can do Press 'Command' and '+' buttons to zoom in. press 'Command' and '-' buttons to zoom out.

wp-admin shows blank page, how to fix it?

I also had a blank screen for my blog. The solution was to copy up a backup copy of wp-config,php somehow the 'live' wp-config.php had been replaced with a file size of zero.

In my case I had the same problem. Helped remove the wp-config.php file. Wordpress created new wp-config.php file and wp-admin is working flawlessly now. Rename plugins, themes folder does not help.

How to export datagridview to excel using

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
End Sub

Private Sub DATAGRIDVIEW_TO_EXCEL(ByVal DGV As DataGridView)
        Dim DTB = New DataTable, RWS As Integer, CLS As Integer

        For CLS = 0 To DGV.ColumnCount - 1 ' COLUMNS OF DTB

        Dim DRW As DataRow

        For RWS = 0 To DGV.Rows.Count - 1 ' FILL DTB WITH DATAGRIDVIEW
            DRW = DTB.NewRow

            For CLS = 0 To DGV.ColumnCount - 1
                    DRW(DTB.Columns(CLS).ColumnName.ToString) = DGV.Rows(RWS).Cells(CLS).Value.ToString
                Catch ex As Exception

                End Try



        Dim DST As New DataSet
        Shell(Chr(34) & EXL & Chr(34) & " " & Chr(34) & FLE & Chr(34), vbNormalFocus) ' OPEN XML WITH EXCEL

    Catch ex As Exception
    End Try

End Sub

How to convert / cast long to String?

String longString = new String(""+long);


String longString = new Long(datelong).toString();

Check if string begins with something?

First, lets extend the string object. Thanks to Ricardo Peres for the prototype, I think using the variable 'string' works better than 'needle' in the context of making it more readable.

String.prototype.beginsWith = function (string) {
    return(this.indexOf(string) === 0);

Then you use it like this. Caution! Makes the code extremely readable.

var pathname = window.location.pathname;
if (pathname.beginsWith('/sub/1')) {
    // Do stuff here

The split() method in Java does not work on a dot (.)

It works fine. Did you read the documentation? The string is converted to a regular expression.

. is the special character matching all input characters.

As with any regular expression special character, you escape with a \. You need an additional \ for the Java string escape.

filter items in a python dictionary where keys contain a specific string

input = {"A":"a", "B":"b", "C":"c"}
output = {k:v for (k,v) in input.items() if key_satifies_condition(k)}

npm WARN enoent ENOENT: no such file or directory, open 'C:\Users\Nuwanst\package.json'

we need to create package.json by entering npm init and enter package name as package.json and optionally fill other requirements else press enter and at last enter yes to confirm. Great!! Now install any npm package without any error.

npm install <package_name>


jQuery - how to check if an element exists?

Assuming you are trying to find if a div exists

$('div').length ? alert('div found') : alert('Div not found')

Check working example at

file_put_contents - failed to open stream: Permission denied

Realise this is pretty old now, but there's no need to manually write queries to a file like this. MySQL has logging support built in, you just need to enable it within your dev environment.

Take a look at the documentation for the 'general query log':

Task<> does not contain a definition for 'GetAwaiter'

I had this issue in one of my projects, where I found that I had set my project's .Net Framework version to 4.0 and async tasks are only supported in .Net Framework 4.5 onwards.

I simply changed my project settings to use .Net Framework 4.5 or above and it worked.

Bootstrap: wider input field

There are various classes for different size inputs







VBA: How to display an error message just like the standard error message which has a "Debug" button?

There is a simpler way simply disable the error handler in your error handler if it does not match the error types you are doing and resume.

The handler below checks agains each error type and if none are a match it returns error resume to normal VBA ie GoTo 0 and resumes the code which then tries to rerun the code and the normal error block pops up.

On Error GoTo ErrorHandler

x = 1/0

if Err.Number = 13 then ' 13 is Type mismatch (only used as an example)

'error handling code for this

end if

If err.Number = 1004 then ' 1004 is Too Large (only used as an example)

'error handling code for this

end if

On Error GoTo 0

Correct mime type for .mp4

video/mp4should be used when you have video content in your file. If there is none, but there is audio, you should use audio/mp4. If no audio and no video is used, for instance if the file contains only a subtitle track or a metadata track, the MIME should be application/mp4. Also, as a server, you should try to include the codecs or profiles parameters as defined in RFC6381, as this will help clients determine if they can play the file, prior to downloading it.

z-index not working with fixed positioning

I was building a nav menu. I have overflow: hidden in my nav's css which hid everything. I thought it was a z-index problem, but really I was hiding everything outside my nav.

Display Bootstrap Modal using javascript onClick

I was looking for the onClick option to set the title and body of the modal based on the item in a list. T145's answer helped a lot, so I wanted to share how I used it.

Make sure the tag containing the JavaScript function is of type text/javascript to avoid conflicts:

<script type="text/javascript"> function showMyModalSetTitle(myTitle, myBodyHtml) {

    * '#myModayTitle' and '#myModalBody' refer to the 'id' of the HTML tags in
    * the modal HTML code that hold the title and body respectively. These id's
    * can be named anything, just make sure they are added as necessary.



This function can now be called in the onClick method from inside an element such as a button:

<button type="button" onClick="javascript:showMyModalSetTitle('Some Title', 'Some body txt')"> Click Me! </button>

Show image using file_get_contents

you can do like this :

    $file = 'your_images.jpg';

    header('Content-Type: image/jpeg');
    header('Content-Length: ' . filesize($file));
    echo file_get_contents($file);

How to change package name in flutter?

Changing name manually doesn't seem to work, throws gradle errors, well in my case it does throw error.

So I usually create a new flutter project.

I use below mentioned command to create a new flutter app

flutter create --org com.yourdomain appname

your project will have the package name as -> com.yourdomain.appname

if you just want to keep your package name as com.appname then make some changes as below

flutter create --org com appname

to add java instead of kotlin for android add -a java

flutter create -a java --org com.yourdomain appname


If you have already created a project you can use change_app_package_name package to change the package name.

flutter pub run change_app_package_name:main com.package.appname

How to create a global variable?

if you want to use it in all of your classes you can use:

public var yourVariable = "something"

if you want to use just in one class you can use :

var yourVariable = "something" local class incompatible:

If you are using the Eclipse IDE, check your Debug/Run configuration. At Classpath tab, select the runner project and click Edit button. Only include exported entries must be checked.

Can I set a TTL for @Cacheable

When using Redis, TTL can be set in properties file like this:

spring.cache.redis.time-to-live=1d # 1 day

spring.cache.redis.time-to-live=5m # 5 minutes

spring.cache.redis.time-to-live=10s # 10 seconds

Deserialize a JSON array in C#

This code is working fine for me,

var a = serializer.Deserialize<List<Entity>>(json);

Getting full-size profile picture

As noted above, it appears that the cover photo of the profile album is a hi-res profile picture. I would check for the album type of "profile" rather than the name though, as the name may not be consistent across different languages, but the type should be.

To reduce the number of requests / parsing, you can use this fql: "select cover_object_id from album where type='profile' and owner = user_id"

And then you can construct the image url with: "" + cover_object_id + "/picture&type=normal&access_token=" + access_token

Looks like there is no "large" type for this image, but the "normal" one is still quite large.

As noted above, this photo may be less accessible than the public profile picture. You need the user_photos or friend_photos permission to access it.

Boolean operators && and ||

The shorter ones are vectorized, meaning they can return a vector, like this:

((-2:2) >= 0) & ((-2:2) <= 0)

The longer form evaluates left to right examining only the first element of each vector, so the above gives

((-2:2) >= 0) && ((-2:2) <= 0)
# [1] FALSE

As the help page says, this makes the longer form "appropriate for programming control-flow and [is] typically preferred in if clauses."

So you want to use the long forms only when you are certain the vectors are length one.

You should be absolutely certain your vectors are only length 1, such as in cases where they are functions that return only length 1 booleans. You want to use the short forms if the vectors are length possibly >1. So if you're not absolutely sure, you should either check first, or use the short form and then use all and any to reduce it to length one for use in control flow statements, like if.

The functions all and any are often used on the result of a vectorized comparison to see if all or any of the comparisons are true, respectively. The results from these functions are sure to be length 1 so they are appropriate for use in if clauses, while the results from the vectorized comparison are not. (Though those results would be appropriate for use in ifelse.

One final difference: the && and || only evaluate as many terms as they need to (which seems to be what is meant by short-circuiting). For example, here's a comparison using an undefined value a; if it didn't short-circuit, as & and | don't, it would give an error.

# Error: object 'a' not found
TRUE || a
# [1] TRUE
FALSE && a
# [1] FALSE
TRUE | a
# Error: object 'a' not found
# Error: object 'a' not found

Finally, see section 8.2.17 in The R Inferno, titled "and and andand".

What is the maximum value for an int32?

The most correct answer I can think of is Int32.MaxValue.

Using Linq to group a list of objects into a new grouped list of list of objects

var groupedCustomerList = userList
    .GroupBy(u => u.GroupID)
    .Select(grp => grp.ToList())

take(1) vs first()

Here are three Observables A, B, and C with marble diagrams to explore the difference between first, take, and single operators:

first vs take vs single operators comparison

* Legend:
--o-- value
----! error
----| completion

Play with it at .

Already having all the answers, I wanted to add a more visual explanation

Hope it helps someone

month name to month number and vice versa in python

If you don't want to import the calendar library, and need something that is a bit more robust -- you can make your code a little bit more dynamic to inconsistent text input than some of the other solutions provided. You can:

  1. Create a month_to_number dictionary
  2. loop through the .items() of that dictionary and check if the lowercase of a string s is in a lowercase key k.

month_to_number = {
'January' : 1,         
'February' : 2,         
'March' : 3,           
'April' : 4,              
'May' : 5, 
'June' : 6,
'July' : 7, 
'August' : 8, 
'September' : 9, 
'October' : 10, 
'November' : 11, 
'December' : 12}

s = 'jun'
[v for k, v in month_to_number.items() if s.lower() in k.lower()][0]

Out[1]: 6

Likewise, if you have a list l instead of a string, you can add another for to loop through the list. The list I have created has inconsistent values, but the output is still what would be desired for the correct month number:

l = ['January', 'february', 'mar', 'Apr', 'MAY', 'JUne', 'july']
[v for k, v in month_to_number.items() for m in l if m.lower() in k.lower()]

Out[2]: [1, 2, 3, 4, 5, 6, 7]

The use case for me here is that I am using Selenium to scrape data from a website by automatically selecting a dropdown value based off of some conditions. Anyway, this requires me relying on some data that I believe our vendor is manually entering to title each month, and I don't want to come back to my code if they format something slightly differently than they have done historically.

How to select a dropdown value in Selenium WebDriver using Java

As discussed above, we need to implement Select Class in Selenium and further we can use various available methods like :- enter image description here

What is the best method of handling currency/money?

My underlying APIs were all using cents to represent money, and I didn't want to change that. Nor was I working with large amounts of money. So I just put this in a helper method:

sprintf("%03d", amount).insert(-3, ".")

That converts the integer to a string with at least three digits (adding leading zeroes if necessary), then inserts a decimal point before the last two digits, never using a Float. From there you can add whatever currency symbols are appropriate for your use case.

It's definitely quick and dirty, but sometimes that's just fine!

Download Excel file via AJAX MVC

On Submit form

public ActionResult ExportXls()
 var filePath="";
  CommonHelper.WriteXls(filePath, "Text.xls");

 public static void WriteXls(string filePath, string targetFileName)
        if (!String.IsNullOrEmpty(filePath))
            HttpResponse response = HttpContext.Current.Response;
            response.Charset = "utf-8";
            response.ContentType = "text/xls";
            response.AddHeader("content-disposition", string.Format("attachment; filename={0}", targetFileName));

Simple and fast method to compare images for similarity

Can the screenshot or icon be transformed (scaled, rotated, skewed ...)? There are quite a few methods on top of my head that could possibly help you:

  • Simple euclidean distance as mentioned by @carlosdc (doesn't work with transformed images and you need a threshold).
  • (Normalized) Cross Correlation - a simple metrics which you can use for comparison of image areas. It's more robust than the simple euclidean distance but doesn't work on transformed images and you will again need a threshold.
  • Histogram comparison - if you use normalized histograms, this method works well and is not affected by affine transforms. The problem is determining the correct threshold. It is also very sensitive to color changes (brightness, contrast etc.). You can combine it with the previous two.
  • Detectors of salient points/areas - such as MSER (Maximally Stable Extremal Regions), SURF or SIFT. These are very robust algorithms and they might be too complicated for your simple task. Good thing is that you do not have to have an exact area with only one icon, these detectors are powerful enough to find the right match. A nice evaluation of these methods is in this paper: Local invariant feature detectors: a survey.

Most of these are already implemented in OpenCV - see for example the cvMatchTemplate method (uses histogram matching): The salient point/area detectors are also available - see OpenCV Feature Detection.

Assign command output to variable in batch file

This post has a method to achieve this

from (zvrba) You can do it by redirecting the output to a file first. For example:

echo zz > bla.txt
set /p VV=<bla.txt
echo %VV%

wildcard * in CSS for classes

What you need is called attribute selector. An example, using your html structure, is the following:

div[class^="tocolor-"], div[class*=" tocolor-"] {

In the place of div you can add any element or remove it altogether, and in the place of class you can add any attribute of the specified element.

[class^="tocolor-"] — starts with "tocolor-".
[class*=" tocolor-"] — contains the substring "tocolor-" occurring directly after a space character.


More information on CSS attribute selectors, you can find here and here. And from MDN Docs MDN Docs

How can I list all collections in the MongoDB shell?

I think one of the biggest confusions is the difference between what you can do with mongo (or an interactive/hybrid shell) vs. mongo --eval (or a pure JavaScript shell). I keep these helpful documents handy:

Here is an example of scripting what you might otherwise do with show commands:

# List all databases and the collections in them

mongo --eval "
        function(v, i){
                v + '\n\t' +

Note: That works really well as a one-liner. (But it looks terrible on Stack Overflow.)

mongo --eval "db.getMongo().getDBNames().forEach(function(v, i){print(v+'\n\t'+db.getSiblingDB(v).getCollectionNames().join('\n\t'))})"


Seems to be identical just in case that SQL server will not try to read data which is not required for the query, the optimizer is clever enough

It can have sense when join on complex query (i.e which have joings, groupings etc itself) then, yes, it is better to specify required fields.

But there is one more point. If the query is simple there is no difference but EVERY extra action even which is supposed to improve performance makes optimizer works harder and optimizer can fail to get the best plan in time and will run not optimal query. So extras select can be a such action which can even decrease performance

Remove attribute "checked" of checkbox

You could try $(this):

$("#captureAudio").live("change", function() {
    if($(this).val() !== undefined) { /* IF THIS VALUE IS NOT UNDEFINED */
            navigator.device.capture.captureAudio(function(mediaFiles) {
        }, function() {
            $(this).removeAttr('checked'); /* REMOVE checked ATTRIBUTE; */
            /* YOU CAN USE `$(this).prop("checked", false);` ALSO */
        }, {limit: 1});

Add colorbar to existing axis

Couldn't add this as a comment, but in case anyone is interested in using the accepted answer with subplots, the divider should be formed on specific axes object (rather than on the numpy.ndarray returned from plt.subplots)

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable
data = np.arange(100, 0, -1).reshape(10, 10)
fig, ax = plt.subplots(ncols=2, nrows=2)
for row in ax:
    for col in row:
        im = col.imshow(data, cmap='bone')
        divider = make_axes_locatable(col)
        cax = divider.append_axes('right', size='5%', pad=0.05)
        fig.colorbar(im, cax=cax, orientation='vertical')

Moving x-axis to the top of a plot in matplotlib



to place the tick marks at the top of the image. The command

ax.set_xlabel('X LABEL')    

affects the label, not the tick marks.

import matplotlib.pyplot as plt
import numpy as np
column_labels = list('ABCD')
row_labels = list('WXYZ')
data = np.random.rand(4, 4)
fig, ax = plt.subplots()
heatmap = ax.pcolor(data,

# put the major ticks at the middle of each cell
ax.set_xticks(np.arange(data.shape[1]) + 0.5, minor=False)
ax.set_yticks(np.arange(data.shape[0]) + 0.5, minor=False)

# want a more natural, table-like display

ax.set_xticklabels(column_labels, minor=False)
ax.set_yticklabels(row_labels, minor=False)

enter image description here

Changing the JFrame title

these methods can help setTitle("your new title"); or super("your new title");

Make iframe automatically adjust height according to the contents without using scrollbar?

I've had problems in the past calling iframe.onload for dynamically created iframes, so I went with this approach for setting the iframe size:

iFrame View

var height = $("body").outerHeight();

Main View

SetIFrameHeight = function(height) {

(this is only going to work if both views are in the same domain)

Rotate a div using javascript

I recently had to build something similar. You can check it out in the snippet below.

The version I had to build uses the same button to start and stop the spinner, but you can manipulate to code if you have a button to start the spin and a different button to stop the spin

Basically, my code looks like this...

Run Code Snippet

var rocket = document.querySelector('.rocket');_x000D_
var btn = document.querySelector('.toggle');_x000D_
var rotate = false;_x000D_
var runner;_x000D_
var degrees = 0;_x000D_
function start(){_x000D_
    runner = setInterval(function(){_x000D_
        degrees++;_x000D_ = 'rotate(' + degrees + 'deg)';_x000D_
function stop(){_x000D_
btn.addEventListener('click', function(){_x000D_
    if (!rotate){_x000D_
        rotate = true;_x000D_
    } else {_x000D_
        rotate = false;_x000D_
body {_x000D_
  background: #1e1e1e;_x000D_
}    _x000D_
.rocket {_x000D_
    width: 150px;_x000D_
    height: 150px;_x000D_
    margin: 1em;_x000D_
    border: 3px dashed teal;_x000D_
    border-radius: 50%;_x000D_
    background-color: rgba(128,128,128,0.5);_x000D_
    display: flex;_x000D_
    justify-content: center;_x000D_
    align-items: center;_x000D_
  .rocket h1 {_x000D_
    margin: 0;_x000D_
    padding: 0;_x000D_
    font-size: .8em;_x000D_
    color: skyblue;_x000D_
    letter-spacing: 1em;_x000D_
    text-shadow: 0 0 10px black;_x000D_
  .toggle {_x000D_
    margin: 10px;_x000D_
    background: #000;_x000D_
    color: white;_x000D_
    font-size: 1em;_x000D_
    padding: .3em;_x000D_
    border: 2px solid red;_x000D_
    outline: none;_x000D_
    letter-spacing: 3px;_x000D_
<div class="rocket"><h1>SPIN ME</h1></div>_x000D_
<button class="toggle">I/0</button>

Change Text Color of Selected Option in a Select Box


<select id="sel" onclick="document.getElementById('sel').style.color='green';">
 <option>Select Your Option</option>
 <option value="">INDIA</option>
 <option value="">USA</option>

The above code will change the colour of text on click of the select box.

and if you want every option different colour, give separate class or id to all options.

How to store .pdf files into MySQL as BLOBs using PHP?

In regards to Gordon M's answer above, the 1st and 2nd parameter in mysqli_real_escape_string () call should be swapped for the newer php versions, according to:

How to sort with a lambda?

Got it.

sort(mMyClassVector.begin(), mMyClassVector.end(), 
    [](const MyClass & a, const MyClass & b) -> bool
    return a.mProperty > b.mProperty; 

I assumed it'd figure out that the > operator returned a bool (per documentation). But apparently it is not so.

gzip: stdin: not in gzip format tar: Child returned status 1 tar: Error is not recoverable: exiting now

Add "-O file.tgz" or "-O file.tar.gz" at the end wget command and extract "file.tgz" or "file.tar.gz"

Here is the sample code for google colab-

!wget -q  --trust-server-names  -O file.tgz 
print("Download completed successfully !!!")
!tar zxvf  file.tgz 

Note- Please ensure that http path for tgz is valid and file is not corrupted

Using DataContractSerializer to serialize, but can't deserialize back

Other solution is:

public static T Deserialize<T>(string rawXml)
    using (XmlReader reader = XmlReader.Create(new StringReader(rawXml)))
        DataContractSerializer formatter0 = 
            new DataContractSerializer(typeof(T));
        return (T)formatter0.ReadObject(reader);

One remark: sometimes it happens that raw xml contains e.g.:

<?xml version="1.0" encoding="utf-16"?>

then of course you can't use UTF8 encoding used in other examples..

Can't access Tomcat using IP address

I was also facing same problem on Amazon windows EC2 instance ( Windows Server 2012 R2 ) Then I figured out , it was local windows firewall preventing it . I opened port 80 ( defined port for website ) using windows Firewall with Advance Security .

It resolved the issue .

Error: Specified cast is not valid. (SqlManagerUI)

Sometimes it happens because of the version change like store 2012 db on 2008, so how to check it?


if it gives error like:

Msg 3241, Level 16, State 13, Line 2 The media family on device 'd:\alibaba.bak' is incorrectly formed. SQL Server cannot process this media family. Msg 3013, Level 16, State 1, Line 2 VERIFY DATABASE is terminating abnormally.

Check it further:


BackupName is "* INCOMPLETE *", Position is "1", other fields are "NULL".

Means either your backup is corrupt or taken from newer version.

Javascript - How to detect if document has loaded (IE 7/Firefox 3)

The above one with JQuery is the easiest and mostly used way. However you can use pure javascript but try to define this script in the head so that it is read at the beginning. What you are looking for is window.onload event.

Below is a simple script that I created to run a counter. The counter then stops after 10 iterations

    var counter = 0;
    var interval1 = setInterval(function()


How do you convert a JavaScript date to UTC?

My solution keeps the date the same no matter what timezone is set on the client-side. Maybe someone will find it useful.

My use case:

I'm creating a todo app, where you set date of your task. This date should remain constant no matter what timezone you're in.

Example. You want to call your friend at 8 am on June 25th.

You create this task 5 days before (June 20th) while you're in China.

Then, on the same day, you fly to New York for a few days.

Then on June 25th, while you're still in New York, you wake up at 7:30 am (which means you should receive task notification in 30 mins (even tho it's 1:30 pm already in China where you were when creating the task)

So the task is ignoring the timezone. It means 'I want to do it at 8 am in whatever timezone I'll be in'.

What I do is let's say 'I assume you're always in London Timezone - UTC'.

What it means is - when the user picks some date in her/his Timezone - I convert this date to the same date in UTC. ie. You pick 8 am in China, but I convert it to 8 am in UTC.

Then - next time you open the app - I read the date saved in UTC and convert it to the same date in your current timezone - eg. I convert 8 am in UTC to 8 am in the New York timezone.

This solution means that the date can mean something else depending on where you are when setting it and where you're reading it, but it remains constant in a way that it 'feels' like you're always in the same timezone.

Let's write some code:

First - we have 2 main functions for converting from/to UTC ignoring timezone:

export function convertLocalDateToUTCIgnoringTimezone(date: Date) {
  const timestamp = Date.UTC(

  return new Date(timestamp);

export function convertUTCToLocalDateIgnoringTimezone(utcDate: Date) {
  return new Date(

Then, I save/read this date like:

function saveTaskDate(localDate: Date) {
  // I convert your local calendar date so it looks like you've picked it being in UTC somewhere around London
  const utcDate = convertLocalDateToUTCIgnoringTimezone(localDate);

function readTaskDate(taskUtcDate: Date) {
  // I convert this UTC date to 'look in your local timezone' as if you were now in UTC somewhere around london
  const localDateWithSameDayAsUTC = convertUTCToLocalDateIgnoringTimezone(taskUtcDate);

  // this date will have the same calendar day as the one you've picked previously
  // no matter where you were saving it and where you are now

How can I check if given int exists in array?

You almost never have to write your own loops in C++. Here, you can use std::find.

const int toFind = 42;
int* found = std::find (myArray, std::end (myArray), toFind);
if (found != std::end (myArray))
  std::cout << "Found.\n"
  std::cout << "Not found.\n";

std::end requires C++11. Without it, you can find the number of elements in the array with:

const size_t numElements = sizeof (myArray) / sizeof (myArray[0]);

...and the end with:

int* end = myArray + numElements;

What's in an Eclipse .classpath/.project file?


When a project is created in the workspace, a project description file is automatically generated that describes the project. The sole purpose of this file is to make the project self-describing, so that a project that is zipped up or released to a server can be correctly recreated in another workspace.


Classpath specifies which Java source files and resource files in a project are considered by the Java builder and specifies how to find types outside of the project. The Java builder compiles the Java source files into the output folder and also copies the resources into it.

How do I parallelize a simple Python loop?

why dont you use threads, and one mutex to protect one global list?

import os
import re
import time
import sys
import thread

from threading import Thread

class thread_it(Thread):
    def __init__ (self,param):
        self.param = param
    def run(self):

threads = []
output = []
mutex = thread.allocate_lock()

for j in range(0, 10):
    current = thread_it(j * offset)

for t in threads:

#here you have output list filled with data

keep in mind, you will be as fast as your slowest thread

How to include !important in jquery

Apparently it's possible to do this in jQuery:

$("#tabs").css("cssText", "height: 650px !important;");


jQuery select child element by class with unknown path

This should do the trick:


How to use sed to extract substring

Explaining how you can use cut:

cat yourxmlfile | cut -d'"' -f2

It will 'cut' all the lines in the file based on " delimiter, and will take the 2nd field , which is what you wanted. invalid stream header: 54657374

Clearly you aren't sending the data with ObjectOutputStream: you are just writing the bytes.

  • If you read with readObject() you must write with writeObject().
  • If you read with readUTF() you must write with writeUTF().
  • If you read with readXXX() you must write with writeXXX(), for most values of XXX.

The 'Access-Control-Allow-Origin' header contains multiple values

I have faced the same issue and this is what I did to resolve it:

In the WebApi service, inside Global.asax I have written the following code:

Sub Application_BeginRequest()
        Dim currentRequest = HttpContext.Current.Request
        Dim currentResponse = HttpContext.Current.Response

        Dim currentOriginValue As String = String.Empty
        Dim currentHostValue As String = String.Empty

        Dim currentRequestOrigin = currentRequest.Headers("Origin")
        Dim currentRequestHost = currentRequest.Headers("Host")

        Dim currentRequestHeaders = currentRequest.Headers("Access-Control-Request-Headers")
        Dim currentRequestMethod = currentRequest.Headers("Access-Control-Request-Method")

        If currentRequestOrigin IsNot Nothing Then
            currentOriginValue = currentRequestOrigin
        End If

        If currentRequest.Path.ToLower().IndexOf("token") > -1 Or Request.HttpMethod = "OPTIONS" Then
            currentResponse.AppendHeader("Access-Control-Allow-Origin", "*")
        End If

        For Each key In Request.Headers.AllKeys
            If key = "Origin" AndAlso Request.HttpMethod = "OPTIONS" Then
                currentResponse.AppendHeader("Access-Control-Allow-Credentials", "true")
                currentResponse.AppendHeader("Access-Control-Allow-Methods", currentRequestMethod)
                currentResponse.AppendHeader("Access-Control-Allow-Headers", If(currentRequestHeaders, "GET,POST,PUT,DELETE,OPTIONS"))
                currentResponse.StatusCode = 200
            End If

    End Sub

Here this code only allows pre-flight and token request to add "Access-Control-Allow-Origin" in the response otherwise I am not adding it.

Here is my blog about the implementation:

Python glob multiple filetypes

You could also use reduce() like so:

import glob
file_types = ['*.txt', '*.mdown', '*.markdown']
project_files = reduce(lambda list1, list2: list1 + list2, (glob.glob(t) for t in file_types))

this creates a list from glob.glob() for each pattern and reduces them to a single list.

how do I initialize a float to its max/min value?

To manually find the minimum of an array you don't need to know the minimum value of float:

float myFloats[];
float minimum = myFloats[0];
for (int i = 0; i < myFloatsSize; ++i)
  if (myFloats[i] < minimum)
    minimum = myFloats[i];

And similar code for the maximum value.

JRE installation directory in Windows

Look the answer to my previous question here

c:\> for %i in (java.exe) do @echo.   %~$PATH:i

Mailto links do nothing in Chrome but work in Firefox?

I solved the problem using this code:

<button onclick="email()">Contact me !</button> _x000D_
function email() {_x000D_
    var str ='mailto:[email protected]', '_blank');_x000D_

It worked for me like a charm !

Bulk load data conversion error (type mismatch or invalid character for the specified codepage) for row 1, column 4 (Year)

Added MSSQLSERVER full access to the folder, diskadmin and bulkadmin server roles.

In my c# application, when preparing for the bulk insert command,

string strsql = "BULK INSERT PWCR_Contractor_vw_TEST FROM '" + strFileName + "' WITH (FIELDTERMINATOR = ',', ROWTERMINATOR = '\\n')";

And I get this error - Bulk load data conversion error (type mismatch or invalid character for the specified codepage) for row 1, column 8 (STATUS).

I looked at my logfile and found that the terminator becomes ' ' instead of '\n'. The OLE DB provider "BULK" for linked server "(null)" reported an error. The provider did not give any information about the error:

Cannot fetch a row from OLE DB provider "BULK" for linked server "(null)". Query :BULK INSERT PWCR_Contractor_vw_TEST FROM 'G:\NEWSTAGEWWW\CalAtlasToPWCR\Results\parsedRegistration.csv' WITH (FIELDTERMINATOR = ',', **ROWTERMINATOR = ''**)

So I added extra escape to the rowterminator - string strsql = "BULK INSERT PWCR_Contractor_vw_TEST FROM '" + strFileName + "' WITH (FIELDTERMINATOR = ',', ROWTERMINATOR = '\\n')";

And now it inserts successfully.

Bulk Insert SQL -   --->  BULK INSERT PWCR_Contractor_vw_TEST FROM 'G:\\NEWSTAGEWWW\\CalAtlasToPWCR\\Results\\parsedRegistration.csv' WITH (FIELDTERMINATOR = ',', ROWTERMINATOR = '\n')
Bulk Insert to PWCR_Contractor_vw_TEST successful...  --->  clsDatase.PerformBulkInsert

Permission is only granted to system app

when your add permission in manifest then in eclipse go to project and clic

  1. click on project
  2. click on clean project that's all

k on clean project

Mac OS X - EnvironmentError: mysql_config not found

Also this happens when I was installing mysqlclient,

$ pip install mysqlclient

As user3429036 said,

$ brew install mysql

How can I convert String to Int?

Try this:

int x = Int32.Parse(TextBoxD1.Text);

or better yet:

int x = 0;

Int32.TryParse(TextBoxD1.Text, out x);

Also, since Int32.TryParse returns a bool you can use its return value to make decisions about the results of the parsing attempt:

int x = 0;

if (Int32.TryParse(TextBoxD1.Text, out x))
    // you know that the parsing attempt
    // was successful

If you are curious, the difference between Parse and TryParse is best summed up like this:

The TryParse method is like the Parse method, except the TryParse method does not throw an exception if the conversion fails. It eliminates the need to use exception handling to test for a FormatException in the event that s is invalid and cannot be successfully parsed. - MSDN

Execute a shell script in current shell with sudo permission

I'm not sure if this breaks any rules but

sudo bash

seems to work for me.

How to send an HTTP request with a header parameter?

If it says the API key is listed as a header, more than likely you need to set it in the headers option of your http request. Normally something like this :

headers: {'Authorization': '[your API key]'}

Here is an example from another Question

$http({method: 'GET', url: '[the-target-url]', headers: {
  'Authorization': '[your-api-key]'}

Edit : Just saw you wanted to store the response in a variable. In this case I would probably just use AJAX. Something like this :

   type : "GET", 
   url : "[the-target-url]", 
   beforeSend: function(xhr){xhr.setRequestHeader('Authorization', '[your-api-key]');},
   success : function(result) { 
       //set your variable to the result 
   error : function(result) { 
     //handle the error 

I got this from this question and I'm at work so I can't test it at the moment but looks solid

Edit 2: Pretty sure you should be able to use this line :

headers: {'Authorization': '[your API key]'},

instead of the beforeSend line in the first edit. This may be simpler for you

How to override and extend basic Django admin templates?

if you need to overwrite the admin/index.html, you can set the index_template parameter of the AdminSite.


from django.contrib import admin = 'admin/my_custom_index.html'

and place your template in <appname>/templates/admin/my_custom_index.html

If else in stored procedure sql server

Thank you all for your answers but I figured out how to do it and the final procedure looks like that :

@ParLngId int output
if not exists (Select ParLngId from T_Param where ParStrIndex = 'RES' and ParStrP2 = 'Web')
            INSERT INTO T_Param values('RES','¤ExtranetClient', 'ECli', 'Web', 1, 1, Null, Null, 'non', 'ExtranetClient', 'ExtranetClient', 25032, Null, '[email protected]', 'Extranet-Client', Null, 27, Null, Null, Null, Null, Null, Null, Null, Null, 1, Null, Null, 0 )
            SET @ParLngId = @@IDENTITY
            SET @ParLngId = (Select top 1 ParLngId from T_Param where ParStrNom = 'Extranet Client')
            Return @ParLngId

So the thing that I found out and which made it works is:

if not exists

It allows us to use a boolean instead of Null or 0 or a number resulted of count()

Failed to load ApplicationContext for JUnit test of Spring controller

There can be multiple root causes for this exception. For me, my mockMvc wasn't getting auto-configured. I solved this exception by using @WebMvcTest(MyController.class) at the class level. This annotation will disable full auto-configuration and instead apply only configuration relevant to MVC tests.

An alternative to this is, If you are looking to load your full application configuration and use MockMVC, you should consider @SpringBootTest combined with @AutoConfigureMockMvc rather than @WebMvcTest

Unlocking tables if thread is lost

how will I know that some tables are locked?

You can use SHOW OPEN TABLES command to view locked tables.

how do I unlock tables manually?

If you know the session ID that locked tables - 'SELECT CONNECTION_ID()', then you can run KILL command to terminate session and unlock tables.

Cannot find Dumpbin.exe

Visual Studio Commmunity 2017 - dumpbin.exe became available once I installed the C++ profiling tools in Modify menu from the Visual Studio Installer.

enter image description here

Pass Javascript variable to PHP via ajax

Pass the data like this to the ajax call (

data: { userID : userID }

And in your PHP do this:

    $uid = $_POST['userID'];

    // Do whatever you want with the $uid

isset() function's purpose is to check wheter the given variable exists, not to get its value.

Calculating number of full months between two dates in SQL


trunc(Months_Between(date2, date1))

Format LocalDateTime with Timezone in Java8"yyyyMMdd HH:mm:ss.SSSSSS Z"));

PL/SQL ORA-01422: exact fetch returns more than requested number of rows

It can also be due to a duplicate entry in any of the tables that are used.

Creating a JavaScript cookie on a domain and reading it across sub domains

Here is a working example :

document.cookie = "testCookie=cookieval; domain=." + 
location.hostname.split('.').reverse()[1] + "." + 
location.hostname.split('.').reverse()[0] + "; path=/"

This is a generic solution that takes the root domain from the location object and sets the cookie. The reversing is because you don't know how many subdomains you have if any.

How do I create directory if it doesn't exist to create a file?

An elegant way to move your file to an nonexistent directory is to create the following extension to native FileInfo class:

public static class FileInfoExtension
    //second parameter is need to avoid collision with native MoveTo
    public static void MoveTo(this FileInfo file, string destination, bool autoCreateDirectory) { 

        if (autoCreateDirectory)
            var destinationDirectory = new DirectoryInfo(Path.GetDirectoryName(destination));

            if (!destinationDirectory.Exists)


Then use brand new MoveTo extension:

 using <namespace of FileInfoExtension>;
 new FileInfo("some path")
     .MoveTo("target path",true);

Check Methods extension documentation.

How to print a string multiple times?

So I take it if the user enters 2, you want the output to be something like:



To get that, you would need something like:

rows = 4
times_to_repeat = int(raw_input("How many times to repeat per row? ")

for i in range(rows):
    print "!" * times_to_repeat

That would result in:

How many times to repeat per row?
>> 4

I have not tested this, but it should run error free.

How to update the constant height constraint of a UIView programmatically?

Change HeightConstraint and WidthConstraint Without creating IBOutlet.

Note: Assign height or width constraint in Storyboard or XIB file. after fetching this Constraint using this extension.

You can use this extension to fetch a height and width Constraint:

extension UIView {

var heightConstraint: NSLayoutConstraint? {
    get {
        return constraints.first(where: {
            $0.firstAttribute == .height && $0.relation == .equal
    set { setNeedsLayout() }

var widthConstraint: NSLayoutConstraint? {
    get {
        return constraints.first(where: {
            $0.firstAttribute == .width && $0.relation == .equal
    set { setNeedsLayout() }


You can use:

yourView.heightConstraint?.constant = newValue 

Java 8 stream map to list of keys sorted by values

You say you want to sort by value, but you don't have that in your code. Pass a lambda (or method reference) to sorted to tell it how you want to sort.

And you want to get the keys; use map to transform entries to keys.

List<Type> types = countByType.entrySet().stream()

How do I run Google Chrome as root?

It no longer suffices to start Chrome with --user-data-dir=/root/.config/google-chrome. It simply prints Aborted and ends (Chrome 48 on Ubuntu 12.04).

You need actually to run it as a non-root user. This you can do with

gksu -wu chrome-user google-chrome

where chrome-user is some user you've decided should be the one to run Chrome. Your Chrome user profile will be found at ~chrome-user/.config/google-chrome.

BTW, the old hack of changing all occurrences of geteuid to getppid in the chrome binary no longer works.

Error 1920 service failed to start. Verify that you have sufficient privileges to start system services

I found this answer on another site but it definitely worked for me so I thought I would share it.

In Windows Explorer: Right Click on the folder OfficeSoftwareProtection Platform from C:\Program Files\Common Files\Microsoft Shared and Microsoft from C:\Program data(this is a hidden folder) Properties > Security > Edit > Add > Type Network Service > OK > Check the Full control box > Apply and OK.

In Registry Editor (regedit.exe): Go to HKEY_CLASSES_ROOT\AppID registry >Right Click on the folder > Permissions > Add > Type = NETWORK SERVICE > OK > Check Full Control > Apply > OK

I found this response here:::

Which was originally a method discovered by Jennifer Zhan

insert a NOT NULL column to an existing table

If you aren't allowing the column to be Null you need to provide a default to populate existing rows. e.g.

    newcol int NOT NULL CONSTRAINT DF_YourTbl_newcol DEFAULT 0

On Enterprise Edition this is a metadata only change since 2012

Convert string to boolean in C#

You must use some of the C # conversion systems:

string to boolean: True to true

string str = "True";
bool mybool = System.Convert.ToBoolean(str);

boolean to string: true to True

bool mybool = true;
string str = System.Convert.ToString(mybool);


string str = mybool.ToString();

bool.Parse expects one parameter which in this case is str, even .

Convert.ToBoolean expects one parameter.

bool.TryParse expects two parameters, one entry (str) and one out (result).

If TryParse is true, then the conversion was correct, otherwise an error occurred

string str = "True";
bool MyBool = bool.Parse(str);


string str = "True";
if(bool.TryParse(str, out bool result))
   //Correct conversion
     //Incorrect, an error has occurred

Get selected element's outer HTML

Note that Josh's solution only works for a single element.

Arguably, "outer" HTML only really makes sense when you have a single element, but there are situations where it makes sense to take a list of HTML elements and turn them into markup.

Extending Josh's solution, this one will handle multiple elements:

(function($) {
  $.fn.outerHTML = function() {
    var $this = $(this);
    if ($this.length>1)
      return $.map($this, function(el){ return $(el).outerHTML(); }).join('');
    return $this.clone().wrap('<div/>').parent().html();

Edit: another problem with Josh's solution fixed, see comment above.

How to convert UTF-8 byte[] to string?

hier is a result where you didnt have to bother with encoding. I used it in my network class and send binary objects as string with it.

        public static byte[] String2ByteArray(string str)
            char[] chars = str.ToArray();
            byte[] bytes = new byte[chars.Length * 2];

            for (int i = 0; i < chars.Length; i++)
                Array.Copy(BitConverter.GetBytes(chars[i]), 0, bytes, i * 2, 2);

            return bytes;

        public static string ByteArray2String(byte[] bytes)
            char[] chars = new char[bytes.Length / 2];

            for (int i = 0; i < chars.Length; i++)
                chars[i] = BitConverter.ToChar(bytes, i * 2);

            return new string(chars);

How to refresh app upon shaking the device?

I have written a small example for detecting vertical and horizontal shakes and showing a Toast.

public class Accelerometerka2Activity extends Activity implements SensorEventListener { 
    private float mLastX, mLastY, mLastZ;
    private boolean mInitialized;
    private SensorManager mSensorManager;
    private Sensor mAccelerometer;
    private final float NOISE = (float) 8.0;

    public void onCreate(Bundle savedInstanceState) {
        mInitialized = false;
        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        mSensorManager.registerListener(this, mAccelerometer , SensorManager.SENSOR_DELAY_NORMAL);

    protected void onResume() {
        mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);

    protected void onPause() {

    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // can be safely ignored for this demo

    public void onSensorChanged(SensorEvent event) {
        float x = event.values[0];
        float y = event.values[1];
        float z = event.values[2];
        if (!mInitialized) {
            mLastX = x;
            mLastY = y;
            mLastZ = z;
            mInitialized = true;
        } else {
            float deltaX = Math.abs(mLastX - x);
            float deltaY = Math.abs(mLastY - y);
            float deltaZ = Math.abs(mLastZ - z);
            if (deltaX < NOISE) deltaX = (float)0.0;
            if (deltaY < NOISE) deltaY = (float)0.0;
            if (deltaZ < NOISE) deltaZ = (float)0.0;
            mLastX = x;
            mLastY = y;
            mLastZ = z;
            if (deltaX > deltaY) {
                Toast.makeText(getBaseContext(), "Horizental", Toast.LENGTH_SHORT).show();
            } else if (deltaY > deltaX) {
                Toast.makeText(getBaseContext(), "Vertical", Toast.LENGTH_SHORT).show();

How do you split and unsplit a window/view in Eclipse IDE?

This is possible with the menu items Window>Editor>Toggle Split Editor.

Current shortcut for splitting is:

Azerty keyboard:

  • Ctrl + _ for split horizontally, and
  • Ctrl + { for split vertically.

Qwerty US keyboard:

  • Ctrl + Shift + - (accessing _) for split horizontally, and
  • Ctrl + Shift + [ (accessing {) for split vertically.

MacOS - Qwerty US keyboard:

  • + Shift + - (accessing _) for split horizontally, and
  • + Shift + [ (accessing {) for split vertically.

On any other keyboard if a required key is unavailable (like { on a german Qwertz keyboard), the following generic approach may work:

  • Alt + ASCII code + Ctrl then release Alt

Example: ASCII for '{' = 123, so press 'Alt', '1', '2', '3', 'Ctrl' and release 'Alt', effectively typing '{' while 'Ctrl' is pressed, to split vertically.

Example of vertical split:


  • The menu items Window>Editor>Toggle Split Editor were added with Eclipse Luna 4.4 M4, as mentioned by Lars Vogel in "Split editor implemented in Eclipse M4 Luna"
  • The split editor is one of the oldest and most upvoted Eclipse bug! Bug 8009
  • The split editor functionality has been developed in Bug 378298, and will be available as of Eclipse Luna M4. The Note & Newsworthy of Eclipse Luna M4 will contain the announcement.

for each loop in groovy

Your code works fine.

def list = [["c":"d"], ["e":"f"], ["g":"h"]]
Map tmpHM = [1:"second (e:f)", 0:"first (c:d)", 2:"third (g:h)"]

for (objKey in tmpHM.keySet()) {   
    HashMap objHM = (HashMap) list.get(objKey);
    print("objHM: ${objHM}  , ")

prints objHM: [e:f] , objHM: [c:d] , objHM: [g:h] ,


Then click "edit in console", "execute script"

Finding the mode of a list

I wrote up this handy function to find the mode.

def mode(nums):
    for i in nums:
            count = nums.count(i)

    for i in corresponding:



    index_v = values.index(maxFreq)
    global mode
    mode = keys[index_v]
    return mode

Can not change UILabel text color

// This is wrong 
categoryTitle.textColor = [UIColor colorWithRed:188 green:149 blue:88 alpha:1.0];

// This should be  
categoryTitle.textColor = [UIColor colorWithRed:188/255 green:149/255 blue:88/255 alpha:1.0];

// In the documentation, the limit of the parameters are mentioned.

colorWithRed:green:blue:alpha: documentation link

Auto-Submit Form using JavaScript

This solution worked for me:

<body onload="setTimeout(function() { document.myform.submit() }, 5000)">
   <form action=TripRecorder name="myform">
      <textarea id="result1"  name="res1" value="str1" cols="20" rows="1" ></textarea> <br> <br/>
      <textarea id="result2" name="res2" value="str2" cols="20" rows="1" ></textarea>

How to set the opacity/alpha of a UIImage?

Swift 5:

extension UIImage {
  func withAlphaComponent(_ alpha: CGFloat) -> UIImage? {
    UIGraphicsBeginImageContextWithOptions(size, false, scale)
    defer { UIGraphicsEndImageContext() }

    draw(at: .zero, blendMode: .normal, alpha: alpha)
    return UIGraphicsGetImageFromCurrentImageContext()

How to bind RadioButtons to an enum?

For the EnumToBooleanConverter answer: Instead of returning DependencyProperty.UnsetValue consider returning Binding.DoNothing for the case where the radio button IsChecked value becomes false. The former indicates a problem (and might show the user a red rectangle or similar validation indicators) while the latter just indicates that nothing should be done, which is what is wanted in that case.

Update a table using JOIN in SQL Server?

    UPDATE mytable
         SET myfield = CASE other_field
             WHEN 1 THEN 'value'
             WHEN 2 THEN 'value'
             WHEN 3 THEN 'value'
    From mytable
    Join otherTable on =
    Where othertable.somecolumn = '1234'

More alternatives here.

How can I symlink a file in Linux?


Where the -s makes it symbolic.

What in the world are Spring beans?

  • Spring beans are just object instances that are managed by the Spring IOC container.

  • Spring IOC container carry the Bag of Bean.Bean creation,maintain and deletion are the responsibilities of Spring Container.

  • We can put the bean in to Spring by Wiring and Auto Wiring.

  • Wiring mean we manually configure it into the XML file.

  • Auto Wiring mean we put the annotations in the Java file then Spring automatically scan the root-context where java configuration file, make it and put into the bag of Spring.

415 Unsupported Media Type - POST json to OData service in lightswitch 2012

It looks like this issue has to do with the difference between the Content-Type and Accept headers. In HTTP, Content-Type is used in request and response payloads to convey the media type of the current payload. Accept is used in request payloads to say what media types the server may use in the response payload.

So, having a Content-Type in a request without a body (like your GET request) has no meaning. When you do a POST request, you are sending a message body, so the Content-Type does matter.

If a server is not able to process the Content-Type of the request, it will return a 415 HTTP error. (If a server is not able to satisfy any of the media types in the request Accept header, it will return a 406 error.)

In OData v3, the media type "application/json" is interpreted to mean the new JSON format ("JSON light"). If the server does not support reading JSON light, it will throw a 415 error when it sees that the incoming request is JSON light. In your payload, your request body is verbose JSON, not JSON light, so the server should be able to process your request. It just doesn't because it sees the JSON light content type.

You could fix this in one of two ways:

  1. Make the Content-Type "application/json;odata=verbose" in your POST request, or
  2. Include the DataServiceVersion header in the request and set it be less than v3. For example:

    DataServiceVersion: 2.0;

(Option 2 assumes that you aren't using any v3 features in your request payload.)

Query to list all users of a certain group

memberOf (in AD) is stored as a list of distinguishedNames. Your filter needs to be something like:


If you don't yet have the distinguished name, you can search for it with:


and return the attribute distinguishedName. Case may matter.

How do I select an element in jQuery by using a variable for the ID?

You can do it like this:

row_id = 5;
row = $("body").find('#'+row_id);

Button that refreshes the page on click

If you are looking for a form reset:

<input type="reset" value="Reset Form Values"/>

or to reset other aspects of the form not handled by the browser

<input type="reset" onclick="doFormReset();" value="Reset Form Values"/>

Using jQuery

function doFormReset(){

Understanding REST: Verbs, error codes, and authentication

re 1: This looks fine so far. Remember to return the URI of the newly created user in a "Location:" header as part of the response to POST, along with a "201 Created" status code.

re 2: Activation via GET is a bad idea, and including the verb in the URI is a design smell. You might want to consider returning a form on a GET. In a Web app, this would be an HTML form with a submit button; in the API use case, you might want to return a representation that contains a URI to PUT to to activate the account. Of course you can include this URI in the response on POST to /users, too. Using PUT will ensure your request is idempotent, i.e. it can safely be sent again if the client isn't sure about success. In general, think about what resources you can turn your verbs into (sort of "nounification of verbs"). Ask yourself what method your specific action is most closely aligned with. E.g. change_password -> PUT; deactivate -> probably DELETE; add_credit -> possibly POST or PUT. Point the client to the appropriate URIs by including them in your representations.

re 3. Don't invent new status codes, unless you believe they're so generic they merit being standardized globally. Try hard to use the most appropriate status code available (read about all of them in RFC 2616). Include additional information in the response body. If you really, really are sure you want to invent a new status code, think again; if you still believe so, make sure to at least pick the right category (1xx -> OK, 2xx -> informational, 3xx -> redirection; 4xx-> client error, 5xx -> server error). Did I mention that inventing new status codes is a bad idea?

re 4. If in any way possible, use the authentication framework built into HTTP. Check out the way Google does authentication in GData. In general, don't put API keys in your URIs. Try to avoid sessions to enhance scalability and support caching - if the response to a request differs because of something that has happened before, you've usually tied yourself to a specific server process instance. It's much better to turn session state into either client state (e.g. make it part of subsequent requests) or make it explicit by turning it into (server) resource state, i.e. give it its own URI.

How to load a model from an HDF5 file in Keras?

See the following sample code on how to Build a basic Keras Neural Net Model, save Model (JSON) & Weights (HDF5) and load them:

# create model
model = Sequential()
model.add(Dense(X.shape[1], input_dim=X.shape[1], activation='relu')) #Input Layer
model.add(Dense(X.shape[1], activation='relu')) #Hidden Layer
model.add(Dense(output_dim, activation='softmax')) #Output Layer

# Compile & Fit model
model.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy']),Y,nb_epoch=5,batch_size=100,verbose=1)    

# serialize model to JSON
model_json = model.to_json()
with open("Data/model.json", "w") as json_file:
    json_file.write(simplejson.dumps(simplejson.loads(model_json), indent=4))

# serialize weights to HDF5
print("Saved model to disk")

# load json and create model
json_file = open('Data/model.json', 'r')
loaded_model_json =
loaded_model = model_from_json(loaded_model_json)

# load weights into new model
print("Loaded model from disk")

# evaluate loaded model on test data 
# Define X_test & Y_test data first
loaded_model.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy'])
score = loaded_model.evaluate(X_test, Y_test, verbose=0)
print ("%s: %.2f%%" % (loaded_model.metrics_names[1], score[1]*100))

Python: split a list based on a condition?

Here's the lazy iterator approach:

from itertools import tee

def split_on_condition(seq, condition):
    l1, l2 = tee((condition(item), item) for item in seq)
    return (i for p, i in l1 if p), (i for p, i in l2 if not p)

It evaluates the condition once per item and returns two generators, first yielding values from the sequence where the condition is true, the other where it's false.

Because it's lazy you can use it on any iterator, even an infinite one:

from itertools import count, islice

def is_prime(n):
    return n > 1 and all(n % i for i in xrange(2, n))

primes, not_primes = split_on_condition(count(), is_prime)
print("First 10 primes", list(islice(primes, 10)))
print("First 10 non-primes", list(islice(not_primes, 10)))

Usually though the non-lazy list returning approach is better:

def split_on_condition(seq, condition):
    a, b = [], []
    for item in seq:
        (a if condition(item) else b).append(item)
    return a, b

Edit: For your more specific usecase of splitting items into different lists by some key, heres a generic function that does that:

DROP_VALUE = lambda _:_
def split_by_key(seq, resultmapping, keyfunc, default=DROP_VALUE):
    """Split a sequence into lists based on a key function.

        seq - input sequence
        resultmapping - a dictionary that maps from target lists to keys that go to that list
        keyfunc - function to calculate the key of an input value
        default - the target where items that don't have a corresponding key go, by default they are dropped
    result_lists = dict((key, []) for key in resultmapping)
    appenders = dict((key, result_lists[target].append) for target, keys in resultmapping.items() for key in keys)

    if default is not DROP_VALUE:
        result_lists.setdefault(default, [])
        default_action = result_lists[default].append
        default_action = DROP_VALUE

    for item in seq:
        appenders.get(keyfunc(item), default_action)(item)

    return result_lists


def file_extension(f):
    return f[2].lower()

split_files = split_by_key(files, {'images': IMAGE_TYPES}, keyfunc=file_extension, default='anims')
print split_files['images']
print split_files['anims']

Routing with multiple Get methods in ASP.NET Web API

I have two get methods with same or no parameters

public IHttpActionResult FirstList()

public IHttpActionResult SecondList()

Just define custom routes in AppStart=>WebApiConfig.cs => under register method

       name: "GetFirstList",
       routeTemplate: "api/Controllername/FirstList"          
       name: "GetSecondList",
       routeTemplate: "api/Controllername/SecondList"          

How do I check whether a file exists without exceptions?

It doesn't seem like there's a meaningful functional difference between try/except and isfile(), so you should use which one makes sense.

If you want to read a file, if it exists, do

    f = open(filepath)
except IOError:
    print 'Oh dear.'

But if you just wanted to rename a file if it exists, and therefore don't need to open it, do

if os.path.isfile(filepath):
    os.rename(filepath, filepath + '.old')

If you want to write to a file, if it doesn't exist, do

# python 2
if not os.path.isfile(filepath):
    f = open(filepath, 'w')

# python 3, x opens for exclusive creation, failing if the file already exists
    f = open(filepath, 'wx')
except IOError:
    print 'file already exists'

If you need file locking, that's a different matter.

Scroll Automatically to the Bottom of the Page

So many answers trying to calculate the height of the document. But it wasn't calculating correctly for me. However, both of these worked:


    $('html,body').animate({scrollTop: 9999});

or just js


How can I regenerate ios folder in React Native project?

Remove the ios folder first

 react-native eject 
 cd ios/ 
 pod init 
 pod install 
 cd .. 
 react-native link 
 cd ios 
 open *.xcworkspace/

Query an XDocument for elements by name at any depth

You can do it this way:

xml.Descendants().Where(p => p.Name.LocalName == "Name of the node to find")

where xml is a XDocument.

Be aware that the property Name returns an object that has a LocalName and a Namespace. That's why you have to use Name.LocalName if you want to compare by name.

How can I create a two dimensional array in JavaScript?

This is mentioned in a few of the comments, but using Array.fill() will help construct a 2-d array:

function create2dArr(x,y) {
    var arr = [];
    for(var i = 0; i < y; i++) {
    return arr; 

this will result in an array of length x, y times in the returned array.

Node.js ES6 classes with require

In class file you can either use:

module.exports = class ClassNameHere {
 print() {
  console.log('In print function');

or you can use this syntax

class ClassNameHere{
  console.log('In print function');

module.exports = ClassNameHere;

On the other hand to use this class in any other file you need to do these steps. First require that file using this syntax: const anyVariableNameHere = require('filePathHere');

Then create an object const classObject = new anyVariableNameHere();

After this you can use classObject to access the actual class variables

CSS selector - element with a given child

I agree that it is not possible in general.

The only thing CSS3 can do (which helped in my case) is to select elements that have no children:

table td:empty
   background-color: white;

Or have any children (including text):

table td:not(:empty)
   background-color: white;

What is javax.inject.Named annotation supposed to be used for?

Regarding #2, according to the JSR-330 spec:

This package provides dependency injection annotations that enable portable classes, but it leaves external dependency configuration up to the injector implementation.

So it's up to the provider to determine which objects are available for injection. In the case of Spring it is all Spring beans. And any class annotated with JSR-330 annotations are automatically added as Spring beans when using an AnnotationConfigApplicationContext.

Can someone explain how to append an element to an array in C programming?

You can have a counter (freePosition), which will track the next free place in an array of size n.

Difference between \w and \b regular expression meta characters

\w is not a word boundary, it matches any word character, including underscores: [a-zA-Z0-9_]. \b is a word boundary, that is, it matches the position between a word and a non-alphanumeric character: \W or [^\w].

These implementations may vary from language to language though.

How can I conditionally require form inputs with AngularJS?

Simple you can use angular validation like :

 <input type='text'

   <input type='text'
   ng-required='!' /> 

You can now fill the value in only one text field. Either you can fill name or lastname. In this way you can use conditional required fill in AngularJs.

how to generate public key from windows command prompt

ssh-keygen isn't a windows executable.
You can use PuttyGen ( for example to create a key

The APR based Apache Tomcat Native library was not found on the java.library.path

not found on the java.library.path: /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib

The native lib is expected in one of the following locations


and not in


The files in tomcat/lib are all jar file and are added by tomcat to the classpath so that they are available to your application.

The native lib is needed by tomcat to perform better on the platform it is installed on and thus cannot be a jar, for linux it could be a .so file, for windows it could be a .dll file.

Just download the native library for your platform and place it in the one of the locations tomcat is expecting it to be.

Note that you are not required to have this lib for development/test purposes. Tomcat runs just fine without it.

org.apache.catalina.startup.Catalina start INFO: Server startup in 2882 ms


The output you are getting is very normal, it's just some logging outputs from tomcat, the line right above indicates that the server correctly started and is ready for operating.

If you are troubling with running your servlet then after the run on sever command eclipse opens a browser window (embeded (default) or external, depends on your config). If nothing shows on the browser, then check the url bar of the browser to see whether your servlet was requested or not.

It should be something like that



Try to call your servlet using the following url


Also each web project has a web.xml, you can find it in your project under WebContent\WEB-INF.

It is better to configure your servlets there using servlet-name servlet-class and url-mapping. It could look like that:

    <display-name>File counter - My first servlet</display-name>


In eclipse dynamic web project the default context name is the same as your project name.


will work too.

set up device for development (???????????? no permissions)

My device is POSITIVO and my operational system is Ubuntu 14.04 LTS So, my problem was in variable name

I create the file /etc/udev/rules.d/51-android.rules and put SUBSYSTEM=="usb", SYSFS{idVendor}=="1662", MODE="0666"

I disconnected device and execute:

$ sudo udevadm control --reload-rules
$ sudo service udev restart

after this i connected the android device in developer mode again and

$ adb devices

List of devices attached 
1A883XB1K   device

First Heroku deploy failed `error code=H10`

For me, I had things unnecessarily split into separate folders. I'm running plotly dash and I had my Procfile, and Pipfile (and lock) together, but separate from the other features of my app ( and, the actual content of the pages being used was in a subfolder). So joining much of that together repaired my H10 error

How to choose between Hudson and Jenkins?

Just my take on the matter, three months later:

Jenkins has continued the path well-trodden by the original Hudson with frequent releases including many minor updates.

Oracle seems to have largely delegated work on the future path for Hudson to the Sonatype team, who has performed some significant changes, especially with respect to Maven. They have jointly moved it to the Eclipse foundation.

I would suggest that if you like the sound of:

  • less frequent releases but ones that are more heavily tested for backwards compatibility (more of an "enterprise-style" release cycle)
  • a product focused primarily on strong Maven and/or Nexus integration (i.e., you have no interest in Gradle and Artifactory etc)
  • professional support offerings from Sonatype or maybe Oracle in preference to Cloudbees etc
  • you don't mind having a smaller community of plugin developers etc.

, then I would suggest Hudson.

Conversely, if you prefer:

  • more frequent updates, even if they require a bit more frequent tweaking and are perhaps slightly riskier in terms of compatibility (more of a "latest and greatest" release cycle)
  • a system with more active community support for e.g., other build systems / artifact repositories
  • support offerings from the original creator et al. and/or you have no interest in professional support (e.g., you're happy as long as you can get a fix in next week's "latest and greatest")
  • a classical OSS-style witches' brew of a development ecosystem

then I would suggest Jenkins. (and as a commenter noted, Jenkins now also has "LTS" releases which are maintained on a more "stable" branch)

The conservative course would be to choose Hudson now and migrate to Jenkins if must-have features are unavailable. The dynamic course would be to choose Jenkins now and migrate to Hudson if chasing updates becomes too time-consuming to justify.

Side-by-side plots with ggplot2

The above solutions may not be efficient if you want to plot multiple ggplot plots using a loop (e.g. as asked here: Creating multiple plots in ggplot with different Y-axis values using a loop), which is a desired step in analyzing the unknown (or large) data-sets (e.g., when you want to plot Counts of all variables in a data-set).

The code below shows how to do that using the mentioned above 'multiplot()', the source of which is here:

plotAllCounts <- function (dt){   
  plots <- list();
  for(i in 1:ncol(dt)) {
    strX = names(dt)[i]
    print(sprintf("%i: strX = %s", i, strX))
    plots[[i]] <- ggplot(dt) + xlab(strX) +

  columnsToPlot <- floor(sqrt(ncol(dt)))
  multiplot(plotlist = plots, cols = columnsToPlot)

Now run the function - to get Counts for all variables printed using ggplot on one page

dt = ggplot2::diamonds

One things to note is that:
using aes(get(strX)), which you would normally use in loops when working with ggplot , in the above code instead of aes_string(strX) will NOT draw the desired plots. Instead, it will plot the last plot many times. I have not figured out why - it may have to do the aes and aes_string are called in ggplot.

Otherwise, hope you'll find the function useful.

Permission denied: /var/www/abc/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable?

If it gets into the selinux arena you've got a much more complicated issue. It's not a good idea to remove the selinux protection but to embrace it and use the tools that were designed to manage it.

If you are serving content out of /var/www/abc, you can verify the selinux permissions with a Z appended to the normal ls -l command. i.e. ls -laZ will give the selinux context.

To add a directory to be served by selinux you can use the semanage command like this. This will change the label on /var/www/abc to httpd_sys_content_t

semanage fcontext -a -t httpd_sys_content_t /var/www/abc

this will update the label for /var/www/abc

restorecon /var/www/abc 

This answer was taken from unixmen and modified to fit this question. I had been searching for this answer for a while and finally found it so felt like I needed to share somewhere. Hope it helps someone.

Attach the Java Source Code

issue resolved here :

"Windows/Preferences": Java > Installed JREs:

then set/update JRE HOME : C:\Program Files\Java\jdk1.8.0_221\jre

should try this.

Populate unique values into a VBA array from Excel

Profiting from the MS Excel 365 function UNIQUE()

In order to enrich the valid solutions above:

Sub ExampleCall()
Dim rng As Range: Set rng = Sheet1.Range("A2:A11")   ' << change to your sheet's Code(Name)
Dim a: a = rng
a = getUniques(a)
arrInfo a
End Sub
Function getUniques(a, Optional ZeroBased As Boolean = True)
Dim tmp: tmp = Application.Transpose(WorksheetFunction.Unique(a))
If ZeroBased Then ReDim Preserve tmp(0 To UBound(tmp) - 1)
getUniques = tmp
End Function

Group By Eloquent ORM

Laravel 5

This is working for me (i use laravel 5.6).

$collection = MyModel::all()->groupBy('column');

If you want to convert the collection to plain php array, you can use toArray()

$array = MyModel::all()->groupBy('column')->toArray();

curl error 18 - transfer closed with outstanding read data remaining

I got this error when my server ran out of disk space and closed the connection midway during generating the response and simply closed the connection

A long bigger than Long.MAX_VALUE

If triangle.lborderA is indeed a long then the test in the original code is trivially true, and there is no way to test it. It is also useless.

However, if triangle.lborderA is a double, the comparison is useful and can be tested. isBiggerThanMaxLong(1e300) does return true.

  public static boolean isBiggerThanMaxLong(double in){
    return in > Long.MAX_VALUE;

How to know that a string starts/ends with a specific string in jQuery?

You do not really need jQuery for such tasks. In the ES6 specification they already have out of the box methods startsWith and endsWith.

var str = "To be, or not to be, that is the question.";
alert(str.startsWith("To be"));         // true
alert(str.startsWith("not to be"));     // false
alert(str.startsWith("not to be", 10)); // true

var str = "To be, or not to be, that is the question.";
alert( str.endsWith("question.") );  // true
alert( str.endsWith("to be") );      // false
alert( str.endsWith("to be", 19) );  // true

Currently available in FF and Chrome. For old browsers you can use their polyfills or substr

How to get character array from a string?

It already is:

var mystring = 'foobar';_x000D_
console.log(mystring[0]); // Outputs 'f'_x000D_
console.log(mystring[3]); // Outputs 'b'

Or for a more older browser friendly version, use:

var mystring = 'foobar';_x000D_
console.log(mystring.charAt(3)); // Outputs 'b'

Trigger an action after selection select2

This worked for me (Select2 4.0.4):

$(document).on('change', 'select#your_id', function(e) {
    // your code
    console.log('this.value', this.value);

Filename too long in Git for Windows

Create .gitconfig and add

longpaths = true

You can create the file in a project location (not sure) and also in the global location. In my case the location is C:\Users\{name}\.

How to detect the currently pressed key?

You can P/Invoke down to the Win32 GetAsyncKeyState to test any key on the keyboard.

You can pass in values from the Keys enum (e.g. Keys.Shift) to this function, so it only requires a couple of lines of code to add it.

Twitter Bootstrap date picker

Much confusion stems from the existence of at least three major libraries named bootstrap-datepicker:

  1. A popular fork of eyecon's datepicker by Andrew 'eternicode' Rowls (use this one!):
  2. The original version by Stefan 'eyecon' Petre, still available at
  3. A totally unrelated datepicker widget that 'storborg' sought to have merged into bootstrap. It wasn't merged and no proper release version of the widget was ever created.

If you're starting a new project - or heck, even if you're taking over an old project using the eyecon version - I recommend that you use eternicode's version, not eyecon's. The original eyecon version is outright inferior in terms of both functionality and documentation, and this is unlikely to change - it has not been updated since March 2013.

You can see most of the capabilities of the eternicode datepicker on the demo page which lets you play with the datepicker's configuration and observe the results. For more detail, see the succinct but comprehensive documentation, which you can probably consume in its entirety in under an hour.

In case you're impatient, though, here's a very short step-by-step guide to the simplest and most common use case for the datepicker.

Quick start guide

  1. Include the following libraries (minimum versions noted here) on your page:
  2. Put an input element on your page somewhere, e.g.

    <input id="my-date-input">
  3. With jQuery, select your input and call the .datepicker() method:

  4. Load your page and click on or tab into your input element. A datepicker will appear:

    Picture of a datepicker

How to add a second x-axis in matplotlib

From matplotlib 3.1 onwards you may use ax.secondary_xaxis

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(1,13, num=301)
y = (np.sin(x)+1.01)*3000

# Define function and its inverse
f = lambda x: 1/(1+x)
g = lambda x: 1/x-1

fig, ax = plt.subplots()
ax.semilogy(x, y, label='DM')

ax2 = ax.secondary_xaxis("top", functions=(f,g))


jQuery's is triggering a 404 (Not Found)

Assuming you've checked the file is actually present on the server, this could also be caused by your web server restricting which file types are served:

HTTP 400 (bad request) for logical error, not malformed request syntax

As of this time, the latest draft of the HTTPbis specification, which is intended to replace and make RFC 2616 obsolete, states:

The 400 (Bad Request) status code indicates that the server cannot or will not process the request because the received syntax is invalid, nonsensical, or exceeds some limitation on what the server is willing to process.

This definition, while of course still subject to change, ratifies the widely used practice of responding to logical errors with a 400.

how to make password textbox value visible when hover an icon

As these guys said, just change input type.
But do not forget to change type back as well.

See my simple jquery demo:


<input name="password" class="password" type="password" />
<div class="icon">icon</div>


$('.icon').hover(function () {
    $('.password').attr('type', 'text');
}, function () {
    $('.password').attr('type', 'password');

Displaying Windows command prompt output and redirecting it to a file

Check this out: wintee

No need for cygwin.

I did encounter and report some issues though.

Also you might check unxutils because it contains tee (and no need for cygwin), but beware that output EOL's are UNIX-like here.

Last, but not least, is if you have PowerShell, you could try Tee-Object. Type get-help tee-object in PowerShell console for more info.

api-ms-win-crt-runtime-l1-1-0.dll is missing when opening Microsoft Office file

While the answer from alireza is correct, it has one gotcha:

You can't install Microsoft Visual C++ 2015 redist (runtime) unless you have Windows Update KB2999226 installed (at least on Windows 7 64-bit SP1).

How to find and restore a deleted file in a Git repository

Find the commit that deleted your file:

git log --diff-filter=D --oneline -- path/to/file | cut -f -d ' '

Sample output:


As of Git 2.23 there is actually a restore command. It is still experimental but in order to restore something you removed in a commit (4711174 in this case) you can then type:

git restore --source=4711174^ path/to/file

Note the ^ after the commit id as we want to restore something from the commit before the one that deleted the file.

The --source argument tells the restore command where to look for the file(s) to restore and it can be any commit and even the index.

See: git-restore doc for git 2.23.0

How to set Default Controller in MVC 4 & MVC 5

the best way is to change your route. The default route (defined in your App_Start) sets /Home/Index

        "Default", // Route name
        "{controller}/{action}/{id}", // URL with parameters*
        new { controller = "Home", action = "Index", 
        id = UrlParameter.Optional }

as the default landing page. You can change that to be any route you wish.

        "Default", // Route name
        "{controller}/{action}/{id}", // URL with parameters*
        new { controller = "Sales", action = "ProjectionReport", 
        id = UrlParameter.Optional }

Spring Boot application can't resolve the org.springframework.boot package

I have this problem when using STS. After edited something, I see that, some workspaces when create a project will happen this problem, and others will not. So I just create a new project in workspaces will not happen.

Google API authentication: Not valid origin for the client

clearing the cache works for me.

for React developers try to restart the project otherwise it will show the same error again and again.

Compiling simple Hello World program on OS X via command line

Compiling it with gcc requires you to pass a number of command line options. Compile it with g++ instead.

Split function equivalent in T-SQL?

  @delimited nvarchar(max),
  @delimiter nvarchar(100)
-- Id column can be commented out, not required for sql splitting string
  id int identity(1,1), -- I use this column for numbering splitted parts
  val nvarchar(max)
  declare @xml xml
  set @xml = N'<root><r>' + replace(@delimited,@delimiter,'</r><r>') + '</r></root>'

  insert into @t(val)
    r.value('.','varchar(max)') as item
  from @xml.nodes('//root/r') as records(r)



Select * from dbo.Split(N'1,2,3,4,6',',')

Complex CSS selector for parent of active child

Unfortunately, there's no way to do that with CSS.

It's not very difficult with JavaScript though:

// JavaScript code:

// jQuery code:
$('.active').parent().get(0); // This would be the <a>'s parent <li>.

Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.12:test (default-test) on project.

Check your test files. You must clear all test files error on your project and try Clean and build.

Why plt.imshow() doesn't display the image?

plt.imshow just finishes drawing a picture instead of printing it. If you want to print the picture, you just need to add

Create Table from View

SQL Server does not support CREATE TABLE AS SELECT.

Use this:

FROM    myview


FROM    myview

How do I install g++ on MacOS X?

Installing XCode requires:

  • Enrolling on the Apple website (not fun)
  • Downloading a 4.7G installer

To install g++ *WITHOUT* having to download the MASSIVE 4.7G xCode install, try this package:

The DMG files linked on that page are ~270M and much quicker to install. This was perfect for me, getting homebrew up and running with a minimum of hassle.

The github project itself is basically a script that repackages just the critical chunks of xCode for distribution. In order to run that script and build the DMG files, you'd need to already have an XCode install, which would kind of defeat the point, so the pre-built DMG files are hosted on the project page.

Add A Year To Today's Date


var date = new Date();

var year = date.getFullYear();

var month = date.getMonth();

month = month + 1;

if (month < 10) {
    month = "0" + month;

var day = date.getDate();

if (day < 10) {
    day = "0" + day;

year = year + 1;

var FullDate =  year + '/' + month + '/' + day; 

Float right and position absolute doesn't work together

Generally speaking, float is a relative positioning statement, since it specifies the position of the element relative to its parent container (floating to the right or left). This means it's incompatible with the position:absolute property, because position:absolute is an absolute positioning statement. You can either float an element and allow the browser to position it relative to its parent container, or you can specify an absolute position and force the element to appear in a certain position regardless of its parent. If you want an absolutely-positioned element to appear on the right side of the screen, you can use position: absolute; right: 0;, but this will cause the element to always appear on the right edge of the screen regardless of how wide its parent div is (so it won't be "at the right of its parent div").

Count Vowels in String Python

What you want can be done quite simply like so:

>>> mystr = input("Please type a sentence: ")
Please type a sentence: abcdE
>>> print(*map(mystr.lower().count, "aeiou"))
1 1 0 0 0

In case you don't know them, here is a reference on map and one on the *.

Checking session if empty or not

If It is simple Session you can apply NULL Check directly Session["emp_num"] != null

But if it's a session of a list Item then You need to apply any one of the following option

Option 1:

if (((List<int>)(Session["emp_num"])) != null && (List<int>)Session["emp_num"])).Count > 0)
 //Your Logic here

Option 2:

List<int> val= Session["emp_num"] as List<int>;  //Get the value from Session.

if (val.FirstOrDefault() != null)
 //Your Logic here

What's the best/easiest GUI Library for Ruby?

Glimmer is an interesting option for JRuby users which provides a very Ruby-ish interface to the SWT toolkit. (SWT is the user interface framework behind Eclipse, which delivers fast performance and familiar UI metaphors by making use of native widgets on the various platforms it supports: Windows, OS X, Linux, etc.) SWT always appealed to me as a Java developer, but coding it was painful in the extreme. Glimmer makes the process a lot more straightforward by emphasizing convention over configuration, and by valuing DRYness and all the other normal Ruby goodness.

Another neat option is SproutCore, a Javascript-based GUI toolkit with Ruby bindings developed by Apple. At least, the demos for it look great, and otherinbox built a pretty slick looking application on top of it. Personally, I've spent quite a few hours trying to get it running on two systems -- one Windows and one Linux -- and haven't succeeded on either one -- I keep running into dependency issues with Merb or other pieces of the SproutCore stack. But it's intriguing enough that I'll go back after a few weeks and try again, hoping that the issues get resolved in that time.

How can I adjust DIV width to contents

You could try using float:left; or display:inline-block;.

Both of these will change the element's behaviour from defaulting to 100% width to defaulting to the natural width of its contents.

However, note that they'll also both have an impact on the layout of the surrounding elements as well. I would suggest that inline-block will have less of an impact though, so probably best to try that first.

How to extract elements from a list using indices in Python?

I think you're looking for this:

elements = [10, 11, 12, 13, 14, 15]
indices = (1,1,2,1,5)

result_list = [elements[i] for i in indices]    

Erase the current printed console line

You can use VT100 escape codes. Most terminals, including xterm, are VT100 aware. For erasing a line, this is ^[[2K. In C this gives:

printf("%c[2K", 27);

Submitting a form by pressing enter without a submit button

This is my solution, tested in Chrome, Firefox 6 and IE7+:

    height: 1px;
    width: 1px;
    position: absolute;
    z-index: -100;

Make XAMPP / Apache serve file outside of htdocs folder

Solution to allow Apache 2 to host websites outside of htdocs:

Underneath the "DocumentRoot" directive in httpd.conf, you should see a directory block. Replace this directory block with:

<Directory />
    Options FollowSymLinks
    AllowOverride All
    Allow from all


Wait for all promises to resolve

The accepted answer is correct. I would like to provide an example to elaborate it a bit to those who aren't familiar with promise.


In my example, I need to replace the src attributes of img tags with different mirror urls if available before rendering the content.

var img_tags = content.querySelectorAll('img');

function checkMirrorAvailability(url) {

    // blah blah 

    return promise;

function changeSrc(success, y, response) {
    if (success === true) {
        img_tags[y].setAttribute('src', response.mirror_url);
    else {
        console.log('No mirrors for: ' + img_tags[y].getAttribute('src'));

var promise_array = [];

for (var y = 0; y < img_tags.length; y++) {
    var img_src = img_tags[y].getAttribute('src');


            // a callback function only accept ONE argument. 
            // Here, we use  `.bind` to pass additional arguments to the
            // callback function (changeSrc).

            // successCallback
            changeSrc.bind(null, true, y),
            // errorCallback
            changeSrc.bind(null, false, y)

    function() {
        console.log('all promises have returned with either success or failure!');
    // We don't need an errorCallback function here, because above we handled
    // all errors.


From AngularJS docs:

The then method:

then(successCallback, errorCallback, notifyCallback) – regardless of when the promise was or will be resolved or rejected, then calls one of the success or error callbacks asynchronously as soon as the result is available. The callbacks are called with a single argument: the result or rejection reason.


Combines multiple promises into a single promise that is resolved when all of the input promises are resolved.

The promises param can be an array of promises.

About bind(), More info here:

IF EXISTS before INSERT, UPDATE, DELETE for optimization

There is a slight effect, since you're doing the same check twice, at least in your example:


Has to query, see if there are any, if true then:

UPDATE Contacs SET [Deleted] = 1 WHERE [Type] = 1

Has to query, see which ones...same check twice for no reason. Now if the condition you're looking for is indexed it ought to be quick, but for large tables you could see some delay just because you're running the select.

Display all items in array using jquery

Use any examples that don't insert each element one at a time, one insertion is most efficient

 $('.element').html( '<span>' + array.join('</span><span>')+'</span>');

Pandas: change data type of Series to String

You can use:

df.loc[:,'id'] = df.loc[:, 'id'].astype(str)

This is why they recommend this solution: Pandas doc


To reflect some of the answers:

df['id'] = df['id'].astype("string")

This will break on the given example because it will try to convert to StringArray which can not handle any number in the 'string'.

df['id']= df['id'].astype(str)

For me this solution throw some warning:

> SettingWithCopyWarning:  
> A value is trying to be set on a copy of a
> slice from a DataFrame. Try using .loc[row_indexer,col_indexer] = value instead

PHP check whether property exists in object or class


echo $person->middleName ?? 'Person does not have a middle name';

To show how this would look in an if statement for more clarity on how this is working.

if($person->middleName ?? false) {
    echo $person->middleName;
} else {
    echo 'Person does not have a middle name';


The traditional PHP way to check for something's existence is to do:

if(isset($person->middleName)) {
    echo $person->middleName;
} else {
    echo 'Person does not have a middle name';

OR for a more class specific way:

if(property_exists($person, 'middleName')) {
    echo $person->middleName;
} else {
    echo 'Person does not have a middle name';

These are both fine in long form statements but in ternary statements they become unnecessarily cumbersome like so:

isset($person->middleName) ? echo $person->middleName : echo 'Person does not have a middle name';

You can also achieve this with just the ternary operator like so:

echo $person->middleName ?: 'Person does not have a middle name';

But... if the value does not exist (is not set) it will raise an E_NOTICE and is not best practise. If the value is null it will not raise the exception.

Therefore ternary operator to the rescue making this a neat little answer:

echo $person->middleName ?? 'Person does not have a middle name';

How to get a single value from FormGroup

This code also works:


CSS - how to make image container width fixed and height auto stretched

No, you can't make the img stretch to fit the div and simultaneously achieve the inverse. You would have an infinite resizing loop. However, you could take some notes from other answers and implement some min and max dimensions but that wasn't the question.

You need to decide if your image will scale to fit its parent or if you want the div to expand to fit its child img.

Using this block tells me you want the image size to be variable so the parent div is the width an image scales to. height: auto is going to keep your image aspect ratio in tact. if you want to stretch the height it needs to be 100% like this fiddle.

img {
    width: 100%;
    height: auto;

Setting HTTP headers

Do not use '*' for Origin, until You really need a completely public behavior.
As Wikipedia says:

"The value of "*" is special in that it does not allow requests to supply credentials, meaning HTTP authentication, client-side SSL certificates, nor does it allow cookies to be sent."

That means, you'll get a lot of errors, especially in Chrome when you'll try to implement for example a simple authentication.

Here is a corrected wrapper:

// Code has not been tested.
func addDefaultHeaders(fn http.HandlerFunc) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        if origin := r.Header.Get("Origin"); origin != "" {
            w.Header().Set("Access-Control-Allow-Origin", origin)
        w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
        w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token")
        w.Header().Set("Access-Control-Allow-Credentials", "true")
        fn(w, r)

And don't forget to reply all these headers to the preflight OPTIONS request.

How to create an empty array in Swift?

Array in swift is written as **Array < Element > **, where Element is the type of values the array is allowed to store.

Array can be initialized as :

let emptyArray = [String]()

It shows that its an array of type string

The type of the emptyArray variable is inferred to be [String] from the type of the initializer.

For Creating the array of type string with elements

var groceryList: [String] = ["Eggs", "Milk"]

groceryList has been initialized with two items

The groceryList variable is declared as “an array of string values”, written as [String]. This particular array has specified a value type of String, it is allowed to store String values only.

There are various properities of array like :

- To check if array has elements (If array is empty or not)

isEmpty property( Boolean ) for checking whether the count property is equal to 0:

if groceryList.isEmpty {
    print("The groceryList list is empty.")
} else {
    print("The groceryList is not empty.")

- Appending(adding) elements in array

You can add a new item to the end of an array by calling the array’s append(_:) method:


groceryList now contains 3 items.

Alternatively, append an array of one or more compatible items with the addition assignment operator (+=):

groceryList += ["Baking Powder"]

groceryList now contains 4 items

groceryList += ["Chocolate Spread", "Cheese", "Peanut Butter"]

groceryList now contains 7 items