Programs & Examples On #Asunit

How to bind RadioButtons to an enum?

I've created a new class to handle binding RadioButtons and CheckBoxes to enums. It works for flagged enums (with multiple checkbox selections) and non-flagged enums for single-selection checkboxes or radio buttons. It also requires no ValueConverters at all.

This might look more complicated at first, however, once you copy this class into your project, it's done. It's generic so it can easily be reused for any enum.

public class EnumSelection<T> : INotifyPropertyChanged where T : struct, IComparable, IFormattable, IConvertible
  private T value; // stored value of the Enum
  private bool isFlagged; // Enum uses flags?
  private bool canDeselect; // Can be deselected? (Radio buttons cannot deselect, checkboxes can)
  private T blankValue; // what is considered the "blank" value if it can be deselected?

  public EnumSelection(T value) : this(value, false, default(T)) { }
  public EnumSelection(T value, bool canDeselect) : this(value, canDeselect, default(T)) { }
  public EnumSelection(T value, T blankValue) : this(value, true, blankValue) { }
  public EnumSelection(T value, bool canDeselect, T blankValue)
    if (!typeof(T).IsEnum) throw new ArgumentException($"{nameof(T)} must be an enum type"); // I really wish there was a way to constrain generic types to enums...
    isFlagged = typeof(T).IsDefined(typeof(FlagsAttribute), false);

    this.value = value;
    this.canDeselect = canDeselect;
    this.blankValue = blankValue;

  public T Value
    get { return value; }
      if (this.value.Equals(value)) return;
      this.value = value;
      OnPropertyChanged("Item[]"); // Notify that the indexer property has changed

  public bool this[T key]
      int iKey = (int)(object)key;
      return isFlagged ? ((int)(object)value & iKey) == iKey : value.Equals(key);
      if (isFlagged)
        int iValue = (int)(object)this.value;
        int iKey = (int)(object)key;

        if (((iValue & iKey) == iKey) == value) return;

        if (value)
          Value = (T)(object)(iValue | iKey);
          Value = (T)(object)(iValue & ~iKey);
        if (this.value.Equals(key) == value) return;
        if (!value && !canDeselect) return;

        Value = value ? key : blankValue;

  public event PropertyChangedEventHandler PropertyChanged;

  private void OnPropertyChanged([CallerMemberName] string propertyName = "")
    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));

And for how to use it, let's say you have an enum for running a task manually or automatically, and can be scheduled for any days of the week, and some optional options...

public enum StartTask

public enum DayOfWeek
  Sunday = 1 << 0,
  Monday = 1 << 1,
  Tuesday = 1 << 2,
  Wednesday = 1 << 3,
  Thursday = 1 << 4,
  Friday = 1 << 5,
  Saturday = 1 << 6

public enum AdditionalOptions
  None = 0,

Now, here's how easy it is to use this class:

public class MyViewModel : ViewModelBase
  public MyViewModel()
    StartUp = new EnumSelection<StartTask>(StartTask.Manual);
    Days = new EnumSelection<DayOfWeek>(default(DayOfWeek));
    Options = new EnumSelection<AdditionalOptions>(AdditionalOptions.None, true, AdditionalOptions.None);

  public EnumSelection<StartTask> StartUp { get; private set; }
  public EnumSelection<DayOfWeek> Days { get; private set; }
  public EnumSelection<AdditionalOptions> Options { get; private set; }

And here's how easy it is to bind checkboxes and radio buttons with this class:

<StackPanel Orientation="Vertical">
  <StackPanel Orientation="Horizontal">
    <!-- Using RadioButtons for exactly 1 selection behavior -->
    <RadioButton IsChecked="{Binding StartUp[Manual]}">Manual</RadioButton>
    <RadioButton IsChecked="{Binding StartUp[Automatic]}">Automatic</RadioButton>
  <StackPanel Orientation="Horizontal">
    <!-- Using CheckBoxes for 0 or Many selection behavior -->
    <CheckBox IsChecked="{Binding Days[Sunday]}">Sunday</CheckBox>
    <CheckBox IsChecked="{Binding Days[Monday]}">Monday</CheckBox>
    <CheckBox IsChecked="{Binding Days[Tuesday]}">Tuesday</CheckBox>
    <CheckBox IsChecked="{Binding Days[Wednesday]}">Wednesday</CheckBox>
    <CheckBox IsChecked="{Binding Days[Thursday]}">Thursday</CheckBox>
    <CheckBox IsChecked="{Binding Days[Friday]}">Friday</CheckBox>
    <CheckBox IsChecked="{Binding Days[Saturday]}">Saturday</CheckBox>
  <StackPanel Orientation="Horizontal">
    <!-- Using CheckBoxes for 0 or 1 selection behavior -->
    <CheckBox IsChecked="{Binding Options[OptionA]}">Option A</CheckBox>
    <CheckBox IsChecked="{Binding Options[OptionB]}">Option B</CheckBox>
  1. When the UI loads, the "Manual" radio button will be selected and you can alter your selection between "Manual" or "Automatic" but either one of them must always be selected.
  2. Every day of the week will be unchecked, but any number of them can be checked or unchecked.
  3. "Option A" and "Option B" will both initially be unchecked. You can check one or the other, checking one will uncheck the other (similar to RadioButtons), but now you can also uncheck both of them (which you cannot do with WPF's RadioButton, which is why CheckBox is being used here)

Converting String to Double in Android

i have a similar problem. for correct formatting EditText text content to double value i use this code:

try {
        String eAm = etAmount.getText().toString();
        DecimalFormat dF = new DecimalFormat("0.00");
        Number num = dF.parse(eAm);
        mPayContext.amount = num.doubleValue();
    } catch (Exception e) {
        mPayContext.amount = 0.0d;

this is independet from current phone locale and return correct double value.

hope it's help;

Short circuit Array.forEach like calling break

This isn't the most efficient, since you still cycle all the elements, but I thought it might be worth considering the very simple:

let keepGoing = true;
things.forEach( (thing) => {
  if (noMore) keepGoing = false;
  if (keepGoing) {
     // do things with thing

Showing line numbers in IPython/Jupyter Notebooks

CTRL - ML toggles line numbers in the CodeMirror area. See the QuickHelp for other keyboard shortcuts.

In more details CTRL - M (or ESC) bring you to command mode, then pressing the L keys should toggle the visibility of current cell line numbers. In more recent notebook versions Shift-L should toggle for all cells.

If you can't remember the shortcut, bring up the command palette Ctrl-Shift+P (Cmd+Shift+P on Mac), and search for "line numbers"), it should allow to toggle and show you the shortcut.

Android: making a fullscreen application

in my case all works fine. See in logcat. Maybe logcat show something that can help you to resolve your problem

Anyway you can try do it programmatically:

 public class ActivityName extends Activity {
        public void onCreate(Bundle savedInstanceState) {
            // remove title

show all tables in DB2 using the LIST command

Run this command line on your preferred shell session:

db2 "select tabname from syscat.tables where owner = 'DB2INST1'"

Maybe you'd like to modify the owner name, and need to check the list of current owners?

db2 "select distinct owner from syscat.tables"

Xcode is not currently available from the Software Update server

If you are trying this on a latest Mac OS X Mavericks, command line tools come with the Xcode 5.x

So make sure you have installed & updated Xcode to latest

after which make sure Xcode command line tools is pointed correctly using this command

xcode-select -p

Which might show some path like


Change the path to correct path using the switch command:

sudo xcode-select --switch /Library/Developer/CommandLineTools/

this should help you set it to correct path, after which you can use the same above command -p to check if it is set correctly

Displaying files (e.g. images) stored in Google Drive on a website

However this answer is simple, infact very simple and yea many have mentioned it that simply put the id of image into the following link{fileId}

But however easy that is, I made a script to run in the console. Feed in an array of complete sharable links from google drive and get them converted into the above link. Then they can be simply used as static addresses.

array = ['','','']_x000D_
function separateDriveImageId(arr) {_x000D_
for (n=0;n<arr.length;n++){_x000D_
str = arr[n]_x000D_
if( str.charAt(i)== '=' ){_x000D_
var num = i+1;_x000D_
var extrctdStrng = str.substr(num)_x000D_

Why is Android Studio reporting "URI is not registered"?

Another suggestion, which was the solution for me: I got the error in the line

<resources xmlns:ns1="" xmlns:ns2="urn:oasis:names:tc:xliff:document:1.2">

in the values.xml file that was automatically generated during the build process.

It was solved by adding the android prefix in the styles.xml file.

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="textColorPrimary">@color/textColorPrimary</item>
        <item name="colorBackground">@color/colorPrimaryDark</item>

had to be changed to

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="android:textColorPrimary">@color/textColorPrimary</item>
        <item name="android:colorBackground">@color/colorPrimaryDark</item>

SQLite: How do I save the result of a query as a CSV file?

Alternatively you can do it in one line (tested in win10)

sqlite3 -help
sqlite3 -header -csv db.sqlite 'select * from tbl1;' > test.csv

Bonus: Using powershell with cmdlet and pipe (|).

get-content query.sql | sqlite3 -header -csv db.sqlite > test.csv

where query.sql is a file containing your SQL query

Getting multiple selected checkbox values in a string in javascript and PHP

I you are using jQuery you can put the checkboxes in a form and then use something like this:

var formData = jQuery("#" + formId).serialize();

      type: "POST",
      url: url,
      data: formData,
      success: success

Joining two table entities in Spring Data JPA

@Query("SELECT rd FROM ReleaseDateType rd, CacheMedia cm WHERE ...")

How to rename a single column in a data.frame?

I would simply change a column name to the dataset with the new name I want with the following code: names(dataset)[index_value] <- "new_col_name"

How to retrieve Request Payload

If I understand the situation correctly, you are just passing json data through the http body, instead of application/x-www-form-urlencoded data.

You can fetch this data with this snippet:

$request_body = file_get_contents('php://input');

If you are passing json, then you can do:

$data = json_decode($request_body);

$data then contains the json data is php array.

php://input is a so called wrapper.

php://input is a read-only stream that allows you to read raw data from the request body. In the case of POST requests, it is preferable to use php://input instead of $HTTP_RAW_POST_DATA as it does not depend on special php.ini directives. Moreover, for those cases where $HTTP_RAW_POST_DATA is not populated by default, it is a potentially less memory intensive alternative to activating always_populate_raw_post_data. php://input is not available with enctype="multipart/form-data".

How can I select from list of values in SQL Server

If you want to select only certain values from a single table you can try this

select distinct(*) from table_name where table_field in (1,1,2,3,4,5)


select first_name,phone_number from telephone_list where district id in (1,2,5,7,8,9)

if you want to select from multiple tables then you must go for UNION.

If you just want to select the values 1, 1, 1, 2, 5, 1, 6 then you must do this

select 1 
union select 1 
union select 1 
union select 2 
union select 5 
union select 1 
union select 6

Can grep show only words that match search pattern?

I had a similar problem, looking for grep/pattern regex and the "matched pattern found" as output.

At the end I used egrep (same regex on grep -e or -G didn't give me the same result of egrep) with the option -o

so, I think that could be something similar to (I'm NOT a regex Master) :

egrep -o "the*|this{1}|thoroughly{1}" filename

Ignoring directories in Git repositories on Windows

This might be extremely obvious for some, but I did understand this from the other answers.

Making a .gitignore file in a directory does nothing by itself. You have to open the .gitignore as a text file and write the files/directories you want it to ignore, each on its own line.

so cd to the Git repository directory

touch .gitignore
nano .gitignore

and then write the names of the files and or directories that you want to be ignored and their extensions if relevant.

Also, .gitignore is a hidden file on some OS (Macs for example) so you need ls -a to see it, not just ls.

Facebook API error 191

I have noticed also that even if you specify your website under secion - Website With Facebook Login -> Site url as e.g., but if your App Domains section is empty, and you open website as you will get this error, too. To avoid it in "App Domains" section write, that will allow subdomains, like, etc

Entity Framework code-first: migration fails with update-database, forces unneccessary(?) add-migration

Entity Framework does have some issues around identity fields.

You can't add GUID identity on existing table

Migrations: does not detect changes to DatabaseGeneratedOption

Reverse engineering does not mark GUID keys with default NEWSEQUENTIALID() as store generated identities

None of these describes your issue exactly and the Down() method in your extra migration is interesting because it appears to be attempting to remove IDENTITY from the column when your CREATE TABLE in the initial migration appears to set it!

Furthermore, if you use Update-Database -Script or Update-Database -Verbose to view the sql that is run from these AlterColumn methods you will see that the sql is identical in Up and Down, and actually does nothing. IDENTITY remains unchanged (for the current version - EF 6.0.2 and below) - as described in the first 2 issues I linked to.

I think you should delete the redundant code in your extra migration and live with an empty migration for now. And you could subscribe to/vote for the issues to be addressed.


Change IDENTITY option does diddly squat

Switch Identity On/Off With A Custom Migration Operation

PHP - Merging two arrays into one array (also Remove Duplicates)

You can use this code to get the desired result. It will remove duplicates.




How to use lifecycle method getDerivedStateFromProps as opposed to componentWillReceiveProps

As we recently posted on the React blog, in the vast majority of cases you don't need getDerivedStateFromProps at all.

If you just want to compute some derived data, either:

  1. Do it right inside render
  2. Or, if re-calculating it is expensive, use a memoization helper like memoize-one.

Here's the simplest "after" example:

import memoize from "memoize-one";

class ExampleComponent extends React.Component {
  getDerivedData = memoize(computeDerivedState);

  render() {
    const derivedData = this.getDerivedData(this.props.someValue);
    // ...

Check out this section of the blog post to learn more.

Insert line after first match using sed

A POSIX compliant one using the s command:

sed '/CLIENTSCRIPT="foo"/s/.*/&\
CLIENTSCRIPT2="hello"/' file

How to send a simple string between two programs using pipes?

Here's a sample:

int main()
    char buff[1024] = {0};
    FILE* cvt;
    int status;
    /* Launch converter and open a pipe through which the parent will write to it */
    cvt = popen("converter", "w");
    if (!cvt)
        printf("couldn't open a pipe; quitting\n");
    printf("enter Fahrenheit degrees: " );
    fgets(buff, sizeof (buff), stdin); /*read user's input */
    /* Send expression to converter for evaluation */
    fprintf(cvt, "%s\n", buff);
    /* Close pipe to converter and wait for it to exit */
    /* Check the exit status of pclose() */
    if (!WIFEXITED(status))
        printf("error on closing the pipe\n");
    return 0;

The important steps in this program are:

  1. The popen() call which establishes the association between a child process and a pipe in the parent.
  2. The fprintf() call that uses the pipe as an ordinary file to write to the child process's stdin or read from its stdout.
  3. The pclose() call that closes the pipe and causes the child process to terminate.

Bootstrap 3 dropdown select

Ive been looking for an nice select dropdown for some time now and I found a good one. So im just gonna leave it here. Its called bootsrap-select

here's the link. check it out. it has editable dropdowns, combo drop downs and more. And its a breeze to add to your project.

If the link dies just search for bootstrap-select by This is better because its a normal select tag

How to cast a double to an int in Java by rounding it down?

In this question:

1.Casting double to integer is very easy task.

2.But it's not rounding double value to the nearest decimal. Therefore casting can be done like this:

double d=99.99999999;
int i=(int)d;

and it will print 99, but rounding hasn't been done.

Thus for rounding we can use,

double d=99.99999999;
System.out.println( Math.round(d));

This will print the output of 100.

How can two strings be concatenated?

Alternatively, if your objective is to output directly to a file or stdout, you can use cat:

cat(s1, s2, sep=", ")

How do you reinstall an app's dependencies using npm?

Follow this step to re install node modules and update them

works even if node_modules folder does not exist. now execute the following command synchronously. you can also use "npm update" but I think this'd preferred way

npm outdated // not necessary to run this command, but this will show outdated dependencies

npm install -g npm-check-updates // to install the "ncu" package

ncu -u --packageFile=package.json // to update dependencies version in package.json...don't run this command if you don't need to update the version

npm install: will install dependencies in your package.json file.

if you're okay with the version of your dependencies in your package.json file, no need to follow those steps just run

 npm install

How to jump back to NERDTree from file in tab?

You can change the tabs by ctrl-pgup and ctrl-pgdown. On that tab you came from the NERDTree is still selected and you can open another tab.

Django Server Error: port is already in use

lsof -t -i tcp:8000 | xargs kill -9

How to use JavaScript to change the form action

function chgAction( action_name )
    if( action_name=="aaa" ) { = "/AAA";
    else if( action_name=="bbb" ) { = "/BBB";
    else if( action_name=="ccc" ) { = "/CCC";

And your form needs to have name in this case:

<form action="/"  accept-charset="UTF-8" method="post" name="search-theme-form" id="search-theme-form">

Setting timezone to UTC (0) in PHP

In PHP DateTime (PHP >= 5.3)

$dt = new DateTime();
$dt->setTimezone(new DateTimeZone('UTC'));
echo $dt->getTimestamp();

How to add directory to classpath in an application run profile in IntelliJ IDEA?

Suppose you need only x:target/classes in your classpath. Then you just add this folder to your classpath and %IDEA%\lib\idea_rt.jar. Now it will work. That's it.

How to remove any URL within a string in Python

import re
s = '''
g = re.findall(r'(text\d+)',s)
print ('list',g)
for i in g:
    print (i)


list ['text1', 'text2', 'text3', 'text4', 'text5', 'text6']
text6    ?

How to update-alternatives to Python 3 without breaking apt?

Somehow python 3 came back (after some updates?) and is causing big issues with apt updates, so I've decided to remove python 3 completely from the alternatives:

root:~# python -V
Python 3.5.2

root:~# update-alternatives --config python
There are 2 choices for the alternative python (providing /usr/bin/python).

  Selection    Path                Priority   Status
* 0            /usr/bin/python3.5   3         auto mode
  1            /usr/bin/python2.7   2         manual mode
  2            /usr/bin/python3.5   3         manual mode

root:~# update-alternatives --remove python /usr/bin/python3.5

root:~# update-alternatives --config python
There is 1 choice for the alternative python (providing /usr/bin/python).

    Selection    Path                Priority   Status
  0            /usr/bin/python2.7   2         auto mode
* 1            /usr/bin/python2.7   2         manual mode

Press <enter> to keep the current choice[*], or type selection number: 0

root:~# python -V
Python 2.7.12

root:~# update-alternatives --config python
There is only one alternative in link group python (providing /usr/bin/python): /usr/bin/python2.7
Nothing to configure.

Display curl output in readable JSON format in Unix shell script

Motivation: You want to print prettify JSON response after curl command request.

Solution: json_pp - commandline tool that converts between some input and output formats (one of them is JSON). This program was copied from json_xs and modified. The default input format is json and the default output format is json with pretty option.

Synposis: json_pp [-v] [-f from_format] [-t to_format] [-json_opt options_to_json1[,options_to_json2[,...]]]

Formula: <someCommand> | json_pp



curl -X | json_pp 


   "completed" : false,
   "id" : 1,
   "title" : "delectus aut autem",
   "userId" : 1

Converting integer to string in Python

You can use %s or .format:

>>> "%s" % 10


>>> '{}'.format(10)

What's the best UI for entering date of birth?

As mentioned in this Jakob Nielsen article, drop down lists should be avoided for data that is well known to the user:

Menus of data well known to users, such as the month and year of their birth. Such information is often hardwired into users' fingers, and having to select such options from a menu breaks the standard paradigm for entering information and can even create more work for users.

The ideal solution is likely something like follows:

  • Provide 3 separate text boxes for day, month, and year (labeled appropriately)
  • Sort the text boxes according to the user's culture.
  • Day and Month text boxes should be sized so that a 2 digit input is assumed.
  • Year text box should be sized so that a 4 digit year is assumed.
  • Allow the user to enter a 2 or 4 digit year. Assume a 2 digit year is 1900, and update the textbox to reflect this onBlur (or on a following confirmation step).
  • Allow the user to enter either a month number OR month name.

EDIT: Here is how we implemented our DOB picker: Masked text input field with HTML5 regex to force the numeric keyboard on iOS devices.

How to check programmatically if an application is installed or not in Android?

Somewhat cleaner solution than the accepted answer (based on this question):

public static boolean isAppInstalled(Context context, String packageName) {
    try {
        context.getPackageManager().getApplicationInfo(packageName, 0);
        return true;
    catch (PackageManager.NameNotFoundException e) {
        return false;

I chose to put it in a helper class as a static utility. Usage example:

boolean whatsappFound = AndroidUtils.isAppInstalled(context, "com.whatsapp");

This answer shows how to get the app from the Play Store if the app is missing, though care needs to be taken on devices that don't have the Play Store.

How to declare and add items to an array in Python?

I believe you are all wrong. you need to do:

array = array[] in order to define it, and then:

array.append ["hello"] to add to it.

How do I update Homebrew?

Alternatively you could update brew by installing it again. (Think I did this as El Capitan changed something)

Note: this is a heavy handed approach that will remove all applications installed via brew!

Try to install brew a fresh and it will tell how to uninstall.

At original time of writing to uninstall:

ruby -e "$(curl -fsSL"

Edit: As of 2020 to uninstall:

/bin/bash -c "$(curl -fsSL"

Working Copy Locked

svn cleanup test-lalala/
svn update

repeat twice

"Permission Denied" trying to run Python on Windows 10

save you time : use wsl and vscode remote extension to properly work with python even with win10 and dont't forget virtualenv! useful

Cannot run emulator in Android Studio

I got it fixed by running "C:\Program Files\Android\android-sdk\AVD Manager.exe" and repairing my broken device.

Set a default parameter value for a JavaScript function

being a long time C++ developer (Rookie to web development :)), when I first came across this situation, I did the parameter assignment in the function definition, like it is mentioned in the question, as follows.

function myfunc(a,b=10)

But beware that it doesn't work consistently across browsers. For me it worked on chrome on my desktop, but did not work on chrome on android. Safer option, as many have mentioned above is -

    function myfunc(a,b)
    if (typeof(b)==='undefined') b = 10;

Intention for this answer is not to repeat the same solutions, what others have already mentioned, but to inform that parameter assignment in the function definition may work on some browsers, but don't rely on it.

Allow only numbers and dot in script

 <script type="text/Javascript">
        function checkDecimal(inputVal) {
            var ex = /^[0-9]+\.?[0-9]*$/;
            if (ex.test(inputVal.value) == false) {
                inputVal.value = inputVal.value.substring(0, inputVal.value.length - 1);

Comparing HTTP and FTP for transferring files

One advantage of FTP is that there is a standard way to list files using dir or ls. Because of this, ftp plays nice with tools such as rsync. Granted, rsync is usually done over ssh, but the option is there.

Spring MVC - Why not able to use @RequestBody and @RequestParam together

The @RequestBody javadoc states

Annotation indicating a method parameter should be bound to the body of the web request.

It uses registered instances of HttpMessageConverter to deserialize the request body into an object of the annotated parameter type.

And the @RequestParam javadoc states

Annotation which indicates that a method parameter should be bound to a web request parameter.

  1. Spring binds the body of the request to the parameter annotated with @RequestBody.

  2. Spring binds request parameters from the request body (url-encoded parameters) to your method parameter. Spring will use the name of the parameter, ie. name, to map the parameter.

  3. Parameters are resolved in order. The @RequestBody is processed first. Spring will consume all the HttpServletRequest InputStream. When it then tries to resolve the @RequestParam, which is by default required, there is no request parameter in the query string or what remains of the request body, ie. nothing. So it fails with 400 because the request can't be correctly handled by the handler method.

  4. The handler for @RequestParam acts first, reading what it can of the HttpServletRequest InputStream to map the request parameter, ie. the whole query string/url-encoded parameters. It does so and gets the value abc mapped to the parameter name. When the handler for @RequestBody runs, there's nothing left in the request body, so the argument used is the empty string.

  5. The handler for @RequestBody reads the body and binds it to the parameter. The handler for @RequestParam can then get the request parameter from the URL query string.

  6. The handler for @RequestParam reads from both the body and the URL query String. It would usually put them in a Map, but since the parameter is of type String, Spring will serialize the Map as comma separated values. The handler for @RequestBody then, again, has nothing left to read from the body.

Bootstrap datepicker hide after selection

Use this for datetimepicker, it works fine


CSS media queries: max-width OR max-height

There are two ways for writing a proper media queries in css. If you are writing media queries for larger device first, then the correct way of writing will be:

@media only screen 
and (min-width : 415px){
    /* Styles */

@media only screen 
and (min-width : 769px){
    /* Styles */

@media only screen 
and (min-width : 992px){
    /* Styles */

But if you are writing media queries for smaller device first, then it would be something like:

@media only screen 
and (max-width : 991px){
    /* Styles */

@media only screen 
and (max-width : 768px){
    /* Styles */

@media only screen 
and (max-width : 414px){
    /* Styles */

Excel doesn't update value unless I hit Enter

Select all the data and use the option "Text to Columns", that will allow your data for Applying Number Formatting ERIK

NodeJS w/Express Error: Cannot GET /

I've noticed that I forgot the "slash" in the beginning of the Route as below and I was getting same error :

Wrong :

app.get('api/courses',  (req, res) => { ... }

Correct :

  app.get('/api/courses',  (req, res) => { ... }

How to check if NSString begins with a certain character

As a more general answer, try using the hasPrefix method. For example, the code below checks to see if a string begins with 10, which is the error code used to identify a certain problem.

NSString* myString = @"10:Username taken";

if([myString hasPrefix:@"10"]) {
      //display more elegant error message

What does 'URI has an authority component' mean?

I found out that the URL of the application conflicted with a module in the Sun GlassFish. So, in the file sun-web.xml I renamed the <context-root>/servlets-samples</context-root>.

It is now working.

What are the differences among grep, awk & sed?

Short definition:

grep: search for specific terms in a file

$ grep This file.txt
Every line containing "This"
Every line containing "This"
Every line containing "This"
Every line containing "This"

$ cat file.txt
Every line containing "This"
Every line containing "This"
Every line containing "That"
Every line containing "This"
Every line containing "This"

Now awk and sed are completly different than grep. awk and sed are text processors. Not only do they have the ability to find what you are looking for in text, they have the ability to remove, add and modify the text as well (and much more).

awk is mostly used for data extraction and reporting. sed is a stream editor
Each one of them has its own functionality and specialties.


$ sed -i 's/cat/dog/' file.txt
# this will replace any occurrence of the characters 'cat' by 'dog'


$ awk '{print $2}' file.txt
# this will print the second column of file.txt

Basic awk usage:
Compute sum/average/max/min/etc. what ever you may need.

$ cat file.txt
A 10
B 20
C 60
$ awk 'BEGIN {sum=0; count=0; OFS="\t"} {sum+=$2; count++} END {print "Average:", sum/count}' file.txt
Average:    30

I recommend that you read this book: Sed & Awk: 2nd Ed.

It will help you become a proficient sed/awk user on any unix-like environment.

How to use Git?

git clone your-url local-dir

to checkout source code;

git pull

to update source code in local-dir;

hadoop No FileSystem for scheme: file

Use this plugin



How to change CSS using jQuery?

Just wanted to add that when using numbers for values with the css method you have to add them outside the apostrophe and then add the CSS unit in apostrophes.

$('.block').css('width',50 + '%');


var $block = $('.block')    

$block.css({ 'width': 50 + '%', 'height': 4 + 'em', 'background': '#FFDAB9' });

What is the difference between print and puts?

puts adds a new line to the end of each argument if there is not one already.

print does not add a new line.

For example:

puts [[1,2,3], [4,5,nil]] Would return:


Whereas print [[1,2,3], [4,5,nil]] would return:

[[1,2,3], [4,5,nil]]
Notice how puts does not output the nil value whereas print does.

How to send a HTTP OPTIONS request from the command line?

The curl installed by default in Debian supports HTTPS since a great while back. (a long time ago there were two separate packages, one with and one without SSL but that's not the case anymore)


You can send an OPTIONS request with curl like this:

curl -i -X OPTIONS

You may also use -v instead of -i to see more output.


To send a plain * (instead of the path, see RFC 7231) with the OPTIONS method, you need curl 7.55.0 or later as then you can run a command line like:

curl -i --request-target "*" -X OPTIONS

How to Get True Size of MySQL Database?

Basically there are two ways: query DB (data length + index length) or check files size. Index length is related to data stored in indexes.

Everything is described here:

Converting file size in bytes to human-readable string

let bytes = 1024 * 10 * 10 * 10;


will return 1000.0?? instead of 1MB

Sort array of objects by single key with date value

As for today, answers of @knowbody ( and @Rocket Hazmat ( can be combined to provide for ES2015 support and correct date handling:

arr.sort((a, b) => {
   const dateA = new Date(a.updated_at);
   const dateB = new Date(b.updated_at);
   return dateA - dateB;

Select value from list of tuples where condition

Yes, you can use filter if you know at which position in the tuple the desired column resides. If the case is that the id is the first element of the tuple then you can filter the list like so:

filter(lambda t: t[0]==10, mylist)

This will return the list of corresponding tuples. If you want the age, just pick the element you want. Instead of filter you could also use list comprehension and pick the element in the first go. You could even unpack it right away (if there is only one result):

[age] = [t[1] for t in mylist if t[0]==10]

But I would strongly recommend to use dictionaries or named tuples for this purpose.

Postgresql, update if row with some unique value exists, else insert

Firstly It tries insert. If there is a conflict on url column then it updates content and last_analyzed fields. If updates are rare this might be better option.

INSERT INTO URLs (url, content, last_analyzed)
SET content=%(content)s, last_analyzed = NOW();

Node.js: how to consume SOAP XML web service

I used the node net module to open a socket to the webservice.

/* on Login request */
socket.on('login', function(credentials /* {username} {password} */){   
    if( !_this.netConnected ){, '', function() {
            logger.gps('(' + ') '+credentials.username+' connected to:');
            _this.netConnected = true;
            _this.username = credentials.username;
            _this.password = credentials.password;
            _this.m_RequestId = 1;
            /* make SOAP Login request */
            soapGps('', _this, 'login', credentials.username);              
    } else {
        /* make SOAP Login request */
        _this.m_RequestId = _this.m_RequestId +1;
        soapGps('', _this, 'login', credentials.username);          

Send soap requests

/* SOAP request func */
module.exports = function soapGps(xmlResponse, client, header, data) {
    /* send Login request */
    if(header == 'login'){
        var SOAP_Headers =  "POST /soap/gps/login HTTP/1.1\r\nHost:\r\nUser-Agent: SOAP-client/SecurityCenter3.0\r\n" +
                            "Content-Type: application/soap+xml; charset=\"utf-8\"";        
        var SOAP_Envelope=  "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" +
                            "<env:Envelope xmlns:env=\"\" xmlns:SOAP-ENC=\"\" xmlns:xsi=\"\" xmlns:xsd=\"\" xmlns:n=\"\"><env:Header><n:Request>" +
                            "Login" +
                            "</n:Request></env:Header><env:Body>" +
                            "<n:RequestLogin xmlns:n=\"\">" +
                            "<n:Name>"+data+"</n:Name>" +
                            "<n:OrgID>0</n:OrgID>" +                                        
                            "<n:LoginEntityType>admin</n:LoginEntityType>" +
                            "<n:AuthType>simple</n:AuthType>" +
                            "</n:RequestLogin></env:Body></env:Envelope>"; + "\r\nContent-Length:" + SOAP_Envelope.length.toString() + "\r\n\r\n");;

Parse soap response, i used module - xml2js

var parser = new xml2js.Parser({
    normalize: true,
    trim: true,
    explicitArray: false
//'utf8');'data', function(response) {

parser.addListener('end', function( xmlResponse ) {
    var response = xmlResponse['env:Envelope']['env:Header']['n:Response']._;
    /* handle Login response */
    if (response == 'Login'){
        /* make SOAP LoginContinue request */
        soapGps(xmlResponse, client, '');
    /* handle LoginContinue response */
    if (response == 'LoginContinue') {
        if(xmlResponse['env:Envelope']['env:Body']['n:ResponseLoginContinue']['n:ErrCode'] == "ok") {           
            var nTimeMsecServer = xmlResponse['env:Envelope']['env:Body']['n:ResponseLoginContinue']['n:CurrentTime'];
            var nTimeMsecOur = new Date().getTime();
        } else {
            /* Unsuccessful login */
  'Error', "invalid login");

Hope it helps someone

What is the difference between RTP or RTSP in a streaming server?

RTSP (actually RTP) can be used for streaming video, but also many other types of media including live presentations. Rtsp is just the protocol used to setup the RTP session.

For all the details you can check out my open source RTSP Server implementation on the following address:

Or my article @

It supports re-sourcing streams as well as the dynamic creation of streams, various RFC's are implemented and the library achieves better performance and less memory then FFMPEG and just about any other solutions in the transport layer and thus makes it a good candidate to use as a centralized point of access for most scenarios.

Ant build failed: "Target "build..xml" does not exist"

Looks like you called it 'ant build..xml'. ant automatically choose a file build.xml in the current directory, so it is enough to call 'ant' (if a default-target is defined) or 'ant target' (the target named target will be called).

With the call 'ant -p' you get a list of targets defined in your build.xml.

Edit: In the comment is shown the call 'ant -verbose build.xml'. To be correct, this has to be called as 'ant -verbose'. The file build.xml in the current directory will be used automatically. If it is needed to explicitly specify the buildfile (because it's name isn't build.xml for example), you have to specify the buildfile with the '-f'-option: 'ant -verbose -f build.xml'. I hope this helps.

PHP check if url parameter exists

It is not quite clear what function you are talking about and if you need 2 separate branches or one. Assuming one:

Change your first line to

$slide = '';
if (isset($_GET["id"]))
    $slide = $_GET["id"];

Why does range(start, end) not include end?

Although there are some useful algorithmic explanations here, I think it may help to add some simple 'real life' reasoning as to why it works this way, which I have found useful when introducing the subject to young newcomers:

With something like 'range(1,10)' confusion can arise from thinking that pair of parameters represents the "start and end".

It is actually start and "stop".

Now, if it were the "end" value then, yes, you might expect that number would be included as the final entry in the sequence. But it is not the "end".

Others mistakenly call that parameter "count" because if you only ever use 'range(n)' then it does, of course, iterate 'n' times. This logic breaks down when you add the start parameter.

So the key point is to remember its name: "stop". That means it is the point at which, when reached, iteration will stop immediately. Not after that point.

So, while "start" does indeed represent the first value to be included, on reaching the "stop" value it 'breaks' rather than continuing to process 'that one as well' before stopping.

One analogy that I have used in explaining this to kids is that, ironically, it is better behaved than kids! It doesn't stop after it supposed to - it stops immediately without finishing what it was doing. (They get this ;) )

Another analogy - when you drive a car you don't pass a stop/yield/'give way' sign and end up with it sitting somewhere next to, or behind, your car. Technically you still haven't reached it when you do stop. It is not included in the 'things you passed on your journey'.

I hope some of that helps in explaining to Pythonitos/Pythonitas!

JAX-WS client : what's the correct path to access the local WSDL?

One other approach that we have taken successfully is to generate the WS client proxy code using wsimport (from Ant, as an Ant task) and specify the wsdlLocation attribute.

<wsimport debug="true" keep="true" verbose="false" target="2.1" sourcedestdir="${generated.client}" wsdl="${src}${wsdl.file}" wsdlLocation="${wsdl.file}">

Since we run this for a project w/ multiple WSDLs, the script resolves the $(wsdl.file} value dynamically which is set up to be /META-INF/wsdl/YourWebServiceName.wsdl relative to the JavaSource location (or /src, depending on how you have your project set up). During the build proess, the WSDL and XSDs files are copied to this location and packaged in the JAR file. (similar to the solution described by Bhasakar above)


Note: make sure the WSDL files are using relative refrerences to any imported XSDs and not http URLs:

      <xsd:import namespace="" schemaLocation="YourWebService_schema1.xsd"/>
      <xsd:import namespace="" schemaLocation="YourWebService_schema2.xsd"/>

In the generated code, we find this:

 * This class was generated by the JAX-WS RI.
 * JAX-WS RI 2.2-b05-
 * Generated source version: 2.1
@WebServiceClient(name = "YourService", targetNamespace = "", wsdlLocation = "/META-INF/wsdl/YourService.wsdl")
public class YourService_Service
    extends Service

    private final static URL YOURWEBSERVICE_WSDL_LOCATION;
    private final static WebServiceException YOURWEBSERVICE_EXCEPTION;
    private final static QName YOURWEBSERVICE_QNAME = new QName("", "YourService");

    static {
        YOURWEBSERVICE_WSDL_LOCATION ="/META-INF/wsdl/YourService.wsdl");
        WebServiceException e = null;
            e = new WebServiceException("Cannot find '/META-INF/wsdl/YourService.wsdl' wsdl. Place the resource correctly in the classpath.");

    public YourService_Service() {
        super(__getWsdlLocation(), YOURWEBSERVICE_QNAME);

    public YourService_Service(URL wsdlLocation, QName serviceName) {
        super(wsdlLocation, serviceName);

     * @return
     *     returns YourService
    @WebEndpoint(name = "YourServicePort")
    public YourService getYourServicePort() {
        return super.getPort(new QName("", "YourServicePort"), YourService.class);

     * @param features
     *     A list of {@link} to configure on the proxy.  Supported features not in the <code>features</code> parameter will have their default values.
     * @return
     *     returns YourService
    @WebEndpoint(name = "YourServicePort")
    public YourService getYourServicePort(WebServiceFeature... features) {
        return super.getPort(new QName("", "YourServicePort"), YourService.class, features);

    private static URL __getWsdlLocation() {
        if (YOURWEBSERVICE_EXCEPTION!= null) {


Perhaps this might help too. It's just a different approach that does not use the "catalog" approach.

Check if a specific value exists at a specific key in any subarray of a multidimensional array

If you have to make a lot of "id" lookups and it should be really fast you should use a second array containing all the "ids" as keys:


foreach($my_array as $arr){

Now you can check for an existing id very fast, for example:

echo (isset($lookup_array[152]))?'yes':'no';

Stretch horizontal ul to fit width of div

inelegant (but effective) way: use percentages

#horizontal-style {
    width: 100%;

li {
    width: 20%;

This only works with the 5 <li> example. For more or less, modify your percentage accordingly. If you have other <li>s on your page, you can always assign these particular ones a class of "menu-li" so that only they are affected.

Changing image size in Markdown

Resizing Markdown Image Attachments in Jupyter Notebook

I'm using jupyter_core-4.4.0 & jupyter notebook.

If you're attaching your images by inserting them into the markdown like this:


These attachment links don't work:

<img src="attachment:Screen%20Shot%202019-08-06%20at%201.48.10%20PM.png" width="500"/>

DO THIS. This does work.

Just add div brackets.

<img src="attachment:Screen%20Shot%202019-08-06%20at%201.48.10%20PM.png" width="500"/>

Hope this helps!

"Please try running this command again as Root/Administrator" error when trying to install LESS

I kept having this problem because windows was setting my node_modules folder to Readonly. Make sure you uncheck this.

enter image description here

Hyper-V: Create shared folder between host and guest with internal network

Share Files, Folders or Drives Between Host and Hyper-V Virtual Machine


  1. Ensure that Enhanced session mode settings are enabled on the Hyper-V host.

    Start Hyper-V Manager, and in the Actions section, select "Hyper-V Settings".


    Make sure that enhanced session mode is allowed in the Server section. Then, make sure that the enhanced session mode is available in the User section.


  2. Enable Hyper-V Guest Services for your virtual machine

    Right-click on Virtual Machine > Settings. Select the Integration Services in the left-lower corner of the menu. Check Guest Service and click OK.


Steps to share devices with Hyper-v virtual machine:

  1. Start a virtual machine and click Show Options in the pop-up windows.


    Or click "Edit Session Settings..." in the Actions panel on the right


    It may only appear when you're (able to get) connected to it. If it doesn't appear try Starting and then Connecting to the VM while paying close attention to the panel in the Hyper-V Manager.

  2. View local resources. Then, select the "More..." menu.


  3. From there, you can choose which devices to share. Removable drives are especially useful for file sharing.


  4. Choose to "Save my settings for future connections to this virtual machine".


  5. Click Connect. Drive sharing is now complete, and you will see the shared drive in this PC > Network Locations section of Windows Explorer after using the enhanced session mode to sigh to the VM. You should now be able to copy files from a physical machine and paste them into a virtual machine, and vice versa.


Source (and for more info): Share Files, Folders or Drives Between Host and Hyper-V Virtual Machine

Mysql where id is in array

$array=array_map('intval', explode(',', $string));
$array = implode("','",$array);
$query=mysqli_query($conn, "SELECT name FROM users WHERE id IN ('".$array."')");

NB: the syntax is:

SELECT * FROM table WHERE column IN('value1','value2','value3')

What are Java command line options to set to allow JVM to be remotely debugged?

Command Line

-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=PORT_NUMBER


gradle bootrun --debug-jvm


mvn spring-boot:run -Drun.jvmArguments="-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=PORT_NUMBER

How to animate a View with Translate Animation in Android

In order to move a View anywhere on the screen, I would recommend placing it in a full screen layout. By doing so, you won't have to worry about clippings or relative coordinates.

You can try this sample code:


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android=""
    android:orientation="vertical" android:id="@+id/rootLayout">

        android:text="MOVE" android:layout_centerHorizontal="true"/>

        android:src="@drawable/ic_launcher" android:layout_marginLeft="10dip"/>
        android:src="@drawable/ic_launcher" android:layout_centerVertical="true" android:layout_alignParentRight="true"/>
        android:src="@drawable/ic_launcher" android:layout_marginLeft="60dip" android:layout_alignParentBottom="true" android:layout_marginBottom="100dip"/>

        android:orientation="vertical" android:clipChildren="false" android:clipToPadding="false">

            android:src="@drawable/ic_launcher" android:layout_marginLeft="60dip" android:layout_marginTop="150dip"/>


Your activity

public void onCreate(Bundle savedInstanceState) {

    ((Button) findViewById( )).setOnClickListener( new OnClickListener()
        public void onClick(View v)
            ImageView img = (ImageView) findViewById( );              
            moveViewToScreenCenter( img );
            img = (ImageView) findViewById( );
            moveViewToScreenCenter( img );
            img = (ImageView) findViewById( );                
            moveViewToScreenCenter( img );
            img = (ImageView) findViewById( );
            moveViewToScreenCenter( img );

private void moveViewToScreenCenter( View view )
    RelativeLayout root = (RelativeLayout) findViewById( );
    DisplayMetrics dm = new DisplayMetrics();
    this.getWindowManager().getDefaultDisplay().getMetrics( dm );
    int statusBarOffset = dm.heightPixels - root.getMeasuredHeight();

    int originalPos[] = new int[2];
    view.getLocationOnScreen( originalPos );

    int xDest = dm.widthPixels/2;
    xDest -= (view.getMeasuredWidth()/2);
    int yDest = dm.heightPixels/2 - (view.getMeasuredHeight()/2) - statusBarOffset;

    TranslateAnimation anim = new TranslateAnimation( 0, xDest - originalPos[0] , 0, yDest - originalPos[1] );
    anim.setFillAfter( true );

The method moveViewToScreenCenter gets the View's absolute coordinates and calculates how much distance has to move from its current position to reach the center of the screen. The statusBarOffset variable measures the status bar height.

I hope you can keep going with this example. Remember that after the animation your view's position is still the initial one. If you tap the MOVE button again and again the same movement will repeat. If you want to change your view's position do it after the animation is finished.

Are members of a C++ struct initialized to 0 by default?

They are not null if you don't initialize the struct.

Snapshot s; // receives no initialization
Snapshot s = {}; // value initializes all members

The second will make all members zero, the first leaves them at unspecified values. Note that it is recursive:

struct Parent { Snapshot s; };
Parent p; // receives no initialization
Parent p = {}; // value initializes all members

The second will make p.s.{x,y} zero. You cannot use these aggregate initializer lists if you've got constructors in your struct. If that is the case, you will have to add proper initalization to those constructors

struct Snapshot {
    int x;
    double y;
    Snapshot():x(0),y(0) { }
    // other ctors / functions...

Will initialize both x and y to 0. Note that you can use x(), y() to initialize them disregarding of their type: That's then value initialization, and usually yields a proper initial value (0 for int, 0.0 for double, calling the default constructor for user defined types that have user declared constructors, ...). This is important especially if your struct is a template.

Adding and using header (HTTP) in nginx

To add a header just add the following code to the location block where you want to add the header:

location some-location {
  add_header X-my-header my-header-content;      

Obviously, replace the x-my-header and my-header-content with what you want to add. And that's all there is to it.

React Checkbox not sending onChange

It's better not to use refs in such cases. Use:


There are some options:

checked vs defaultChecked

The former would respond to both state changes and clicks. The latter would ignore state changes.

onClick vs onChange

The former would always trigger on clicks. The latter would not trigger on clicks if checked attribute is present on input element.

How many characters in varchar(max)


varchar [ ( n | max ) ] Variable-length, non-Unicode character data. n can be a value from 1 through 8,000. max indicates that the maximum storage size is 2^31-1 bytes. The storage size is the actual length of data entered + 2 bytes. The data entered can be 0 characters in length. The ISO synonyms for varchar are char varying or character varying.

1 character = 1 byte. And don't forget 2 bytes for the termination. So, 2^31-3 characters.

Npm install failed with "cannot run in wd"

OP here, I have learned a lot more about node since I first asked this question. Though Dmitry's answer was very helpful, what ultimately did it for me is to install node with the correct permissions.

I highly recommend not installing node using any package managers, but rather to compile it yourself so that it resides in a local directory with normal permissions.

This article provides a very clear step-by-step instruction of how to do so:

How to convert a char array back to a string?

1 alternate way is to do:

String b = a + "";

How to obtain a QuerySet of all rows, with specific fields for each one of them?

Employees.objects.values_list('eng_name', flat=True)

That creates a flat list of all eng_names. If you want more than one field per row, you can't do a flat list: this will create a list of tuples:

Employees.objects.values_list('eng_name', 'rank')

Visual Studio Post Build Event - Copy to Relative Directory Location

I think this is related, but I had a problem when building directly using msbuild command line (from a batch file) vs building from within VS.

Using something like the following:

  MOVE /Y "$(TargetDir)something.file1" "$(ProjectDir)something.file1"
  start XCOPY /Y /R "$(SolutionDir)SomeConsoleApp\bin\$(ConfigurationName)\*" "$(ProjectDir)App_Data\Consoles\SomeConsoleApp\"

(note: start XCOPY rather than XCOPY used to get around a permissions issue which prevented copying)

The macro $(SolutionDir) evaluated to ..\ when executing msbuild from a batchfile, which resulted in the XCOPY command failing. It otherwise worked fine when built from within Visual Studio. Confirmed using /verbosity:diagnostic to see the evaluated output.

Using the macro $(ProjectDir)..\ instead, which amounts to the same thing, worked fine and retained the full path in both build scenarios.

Regular expression matching a multiline block of text

If each file only has one sequence of aminoacids, I wouldn't use regular expressions at all. Just something like this:

def read_amino_acid_sequence(path):
    with open(path) as sequence_file:
        title = sequence_file.readline() # read 1st line
        aminoacid_sequence = # read the rest

    # some cleanup, if necessary
    title = title.strip() # remove trailing white spaces and newline
    aminoacid_sequence = aminoacid_sequence.replace(" ","").replace("\n","")
    return title, aminoacid_sequence

Group by with union mysql select query

select sum(qty), name
from (
    select count(m.owner_id) as qty,
    from transport t,owner o,motorbike m
    where t.type='motobike' and o.owner_id=m.owner_id
        and t.type_id=m.motorbike_id
    group by m.owner_id

    union all

    select count(c.owner_id) as qty,,
    from transport t,owner o,car c
    where t.type='car' and o.owner_id=c.owner_id and t.type_id=c.car_id
    group by c.owner_id
) t
group by name

Wait for Angular 2 to load/resolve model before rendering view/template

Implement the routerOnActivate in your @Component and return your promise:

EDIT: This explicitly does NOT work, although the current documentation can be a little hard to interpret on this topic. See Brandon's first comment here for more information:

EDIT: The related information on the otherwise-usually-accurate Auth0 site is not correct:

EDIT: The angular team is planning a @Resolve decorator for this purpose.

Notepad++ add to every line

In order to do it in one go:

  1. Copy and paste the following example text in your notepad++ window:




  1. Press Ctrl+H on the notepad++ window
  2. In the Find what box type: ^(.+)$. Here ^ represents the start of the line. $ represents the end of the line. (.+) means any character in between the start and the end of the line and it would be group 1.
  3. In the Replace with box type: WhateverFrontText(\1)WhatEverEndText. Here (\1) means whatever text in a line.
  4. Check the check box Wrap around
  5. Search mode: Regular expression
  6. Result:




  1. Screenshot of the notepad++ options and result: enter image description here

Align two inline-blocks left and right on same line

If you're already using JavaScript to center stuff when the screen is too small (as per your comment for your header), why not just undo floats/margins with JavaScript while you're at it and use floats and margins normally.

You could even use CSS media queries to reduce the amount JavaScript you're using.

How to chain scope queries with OR instead of AND?

names = ["tim", "tom", "bob", "alex"]
sql_string = { |t| "name = '#{t}'" }.join(" OR ")
@people = People.where(sql_string)

Difference between __getattr__ vs __getattribute__

I find that no one mentions this difference:

__getattribute__ has a default implementation, but __getattr__ does not.

class A:
a = A()
a.__getattr__ # error
a.__getattribute__ # return a method-wrapper

This has a clear meaning: since __getattribute__ has a default implementation, while __getattr__ not, clearly python encourages users to implement __getattr__.

How to make HTML table cell editable?

This is a runnable example.

    if($(this).children("input").length > 0)
          return false;

    var tdObj = $(this);
    var preText = tdObj.html();
    var inputObj = $("<input type='text' />");


      if(13 == event.which) { // press ENTER-key
        var text = $(this).val();
      else if(27 == event.which) {  // press ESC-key
      return false;
        <!-- jQuery source -->
        <script src=""></script>
        <table align="center">
            <tr> <td>id</td> <td>name</td> </tr>
            <tr> <td>001</td> <td>dog</td> </tr>
            <tr> <td>002</td> <td>cat</td> </tr>
            <tr> <td>003</td> <td>pig</td> </tr>

How to Validate Google reCaptcha on Form Submit

Try this link:

A link to that page is posted at the very bottom of this page:

One issue I came up with that prevented these two files from working correctly was with my php.ini file for the website. Make sure this property is setup properly, as follows: allow_url_fopen = On

Scale an equation to fit exact page width




Is there an XSLT name-of element?

<xsl:value-of select="name(.)" /> : <xsl:value-of select="."/>

Integer division: How do you produce a double?

just use this.

int fxd=1;
double percent= (double)(fxd*40)/100;

Media Queries: How to target desktop, tablet, and mobile?

One extra feature is you can also use-media queries in the media attribute of the <link> tag.

<link href="style.css" rel="stylesheet">
<link href="justForFrint.css" rel="stylesheet" media="print">
<link href="deviceSizeDepending.css" rel="stylesheet" media="(min-width: 40em)">

With this, the browser will download all CSS resources, regardless of the media attribute. The difference is that if the media-query of the media attribute is evaluated to false then that .css file and his content will not be render-blocking.

Therefore, it is recommended to use the media attribute in the <link> tag since it guarantees a better user experience.

Here you can read a Google article about this issue

Some tools that will help you to automate the separation of your css code in different files according to your media-querys



How do you reindex an array in PHP but with indexes starting from 1?

Duplicate removal and reindex an array:

   $oldArray = array('0'=>'php','1'=>'java','2'=>'','3'=>'asp','4'=>'','5'=>'mysql');
   //duplicate removal
   $fillteredArray = array_filter($oldArray);
   //reindexing actually happens  here
   $newArray = array_merge($filteredArray);

"error: assignment to expression with array type error" when I assign a struct field (C)

You are facing issue in"Paolo";

because, in the LHS, you're using an array type, which is not assignable.

To elaborate, from C11, chapter §6.5.16

assignment operator shall have a modifiable lvalue as its left operand.

and, regarding the modifiable lvalue, from chapter §

A modifiable lvalue is an lvalue that does not have array type, [...]

You need to use strcpy() to copy into the array.

That said, data s1 = {"Paolo", "Rossi", 19}; works fine, because this is not a direct assignment involving assignment operator. There we're using a brace-enclosed initializer list to provide the initial values of the object. That follows the law of initialization, as mentioned in chapter §6.7.9

Each brace-enclosed initializer list has an associated current object. When no designations are present, subobjects of the current object are initialized in order according to the type of the current object: array elements in increasing subscript order, structure members in declaration order, and the first named member of a union.[....]

How to extract the hostname portion of a URL in JavaScript

My solution works in all web browsers including Microsoft Internet Explorer and doesn't use any regular expression, it's inspired of Noah Cardoza and Martin Konecny solutions:

function getHostname(href) {
    if (typeof URL === 'object') {
        // workaround for MS IE 11 (Noah Cardoza's solution but without using Object.assign())
        var dummyNode = document.createElement('a');
        dummyNode.href = href;
        return dummyNode.hostname;
    } else {
        // Martin Konecny's solution
        return new URL(href).hostname;

Set content of iframe

Unified Solution:

In order to work on all modern browsers, you will need two steps:

  1. Add javascript:void(0); as src attribute for the iframe element. Otherwise the content will be overriden by the empty src on Firefox.

    <iframe src="javascript:void(0);"></iframe>
  2. Programatically change the content of the inner html element.



Step 1 from comment (link) by @susan

Step 2 from solutions (link1, link2) by @erimerturk and @x10

Iterate over elements of List and Map using JSTL <c:forEach> tag

Mark, this is already answered in your previous topic. But OK, here it is again:

Suppose ${list} points to a List<Object>, then the following

<c:forEach items="${list}" var="item">

does basically the same as as following in "normal Java":

for (Object item : list) {

If you have a List<Map<K, V>> instead, then the following

<c:forEach items="${list}" var="map">
    <c:forEach items="${map}" var="entry">

does basically the same as as following in "normal Java":

for (Map<K, V> map : list) {
    for (Entry<K, V> entry : map.entrySet()) {

The key and value are here not special methods or so. They are actually getter methods of Map.Entry object (click at the blue Map.Entry link to see the API doc). In EL (Expression Language) you can use the . dot operator to access getter methods using "property name" (the getter method name without the get prefix), all just according the Javabean specification.

That said, you really need to cleanup the "answers" in your previous topic as they adds noise to the question. Also read the comments I posted in your "answers".

Clear back stack using fragments

Reading the documentation and studying what the fragment id is, it appears to simply be the stack index, so this works:

fragmentManager.popBackStackImmediate(0, FragmentManager.POP_BACK_STACK_INCLUSIVE);

Zero (0) is the the bottom of the stack, so popping up to it inclusive clears the stack.

CAVEAT: Although the above works in my program, I hesitate a bit because the FragmentManager documentation never actually states that the id is the stack index. It makes sense that it would be, and all my debug logs bare out that it is, but perhaps in some special circumstance it would not? Can any one confirm this one way or the other? If it is, then the above is the best solution. If not, this is the alternative:

while(fragmentManager.getBackStackEntryCount() > 0) { fragmentManager.popBackStackImmediate(); }

Can dplyr join on multiple columns or composite key?

Updating to use tibble()

You can pass a named vector of length greater than 1 to the by argument of left_join():


d1 <- tibble(
  x = letters[1:3],
  y = LETTERS[1:3],
  a = rnorm(3)

d2 <- tibble(
  x2 = letters[3:1],
  y2 = LETTERS[3:1],
  b = rnorm(3)

left_join(d1, d2, by = c("x" = "x2", "y" = "y2"))

Client on Node.js: Uncaught ReferenceError: require is not defined

Even using this won't work. I think the best solution is Browserify:

module.exports = {
  func1: function () {
   console.log("I am function 1");
  func2: function () {
    console.log("I am function 2");

var common = require('./common');

What is the difference between const and readonly in C#?

There is notable difference between const and readonly fields in C#.Net

const is by default static and needs to be initialized with constant value, which can not be modified later on. Change of value is not allowed in constructors, too. It can not be used with all datatypes. For ex- DateTime. It can not be used with DateTime datatype.

public const DateTime dt = DateTime.Today;  //throws compilation error
public const string Name = string.Empty;    //throws compilation error
public readonly string Name = string.Empty; //No error, legal

readonly can be declared as static, but not necessary. No need to initialize at the time of declaration. Its value can be assigned or changed using constructor. So, it gives advantage when used as instance class member. Two different instantiation may have different value of readonly field. For ex -

class A
    public readonly int Id;

    public A(int i)
        Id = i;

Then readonly field can be initialised with instant specific values, as follows:

A objOne = new A(5);
A objTwo = new A(10);

Here, instance objOne will have value of readonly field as 5 and objTwo has 10. Which is not possible using const.

How to store NULL values in datetime fields in MySQL?

This is a a sensible point.

A null date is not a zero date. They may look the same, but they ain't. In mysql, a null date value is null. A zero date value is an empty string ('') and '0000-00-00 00:00:00'

On a null date "... where mydate = ''" will fail.
On an empty/zero date "... where mydate is null" will fail.

But now let's get funky. In mysql dates, empty/zero date are strictly the same.

by example

select if(myDate is null, 'null', myDate) as mydate from myTable where  myDate = '';
select if(myDate is null, 'null', myDate) as mydate from myTable where  myDate = '0000-00-00 00:00:00'

will BOTH output: '0000-00-00 00:00:00'. if you update myDate with '' or '0000-00-00 00:00:00', both selects will still work the same.

In php, the mysql null dates type will be respected with the standard mysql connector, and be real nulls ($var === null, is_null($var)). Empty dates will always be represented as '0000-00-00 00:00:00'.

I strongly advise to use only null dates, OR only empty dates if you can. (some systems will use "virual" zero dates which are valid Gregorian dates, like 1970-01-01 (linux) or 0001-01-01 (oracle).

empty dates are easier in php/mysql. You don't have the "where field is null" to handle. However, you have to "manually" transform the '0000-00-00 00:00:00' date in '' to display empty fields. (to store or search you don't have special case to handle for zero dates, which is nice).

Null dates need better care. you have to be careful when you insert or update to NOT add quotes around null, else a zero date will be inserted instead of null, which causes your standard data havoc. In search forms, you will need to handle cases like "and mydate is not null", and so on.

Null dates are usually more work. but they much MUCH MUCH faster than zero dates for queries.

Include CSS,javascript file in Yii Framework

Also, if you want to add module assets both CSS and JS, you can use the following logic. See how you need to indicate the correct path to getPathOfAlias:

public static function register($file)
    $url = Yii::app()->getAssetManager()->publish(

    $path = $url . '/' . $file;
    if(strpos($file, 'js') !== false)
        return Yii::app()->clientScript->registerScriptFile($path);
    else if(strpos($file, 'css') !== false)
        return Yii::app()->clientScript->registerCssFile($path);

    return $path;

The above code has been taken from GPLed Yii based Webshop app.

How to solve npm install throwing fsevents warning on non-MAC OS?

package.json counts with a optionalDependencies key. NPM on Optional Dependencies.

You can add fsevents to this object and if you find yourself installing packages in a different platform than MacOS, fsevents will be skipped by either yarn or npm.

"optionalDependencies": {
  "fsevents": "2.1.2"

You will find a message like the following in the installation log:

info [email protected]: The platform "linux" is incompatible with this module.
info "[email protected]" is an optional dependency and failed compatibility check. Excluding it from installation.
info [email protected]: The platform "linux" is incompatible with this module.
info "[email protected]" is an optional dependency and failed compatibility check. Excluding it from installation.

Hope it helps!

Stop all active ajax requests in jQuery

Here's how to hook this up on any click (useful if your page is placing many AJAX calls and you're trying to navigate away).

$ ->
    $.xhrPool = [];

$(document).ajaxSend (e, jqXHR, options) ->

$(document).ajaxComplete (e, jqXHR, options) ->
    $.xhrPool = $.grep($.xhrPool, (x) -> return x != jqXHR);

$(document).delegate 'a', 'click', ->
    while (request = $.xhrPool.pop())

event Action<> vs event EventHandler<>

On the most part, I'd say follow the pattern. I have deviated from it, but very rarely, and for specific reasons. In the case in point, the biggest issue I'd have is that I'd probably still use an Action<SomeObjectType>, allowing me to add extra properties later, and to use the occasional 2-way property (think Handled, or other feedback-events where the subscriber needs to to set a property on the event object). And once you've started down that line, you might as well use EventHandler<T> for some T.

Each for object?

var object = { "a": 1, "b": 2};_x000D_
$.each(object, function(key, value){_x000D_
  console.log(key + ": " + object[key]);_x000D_
<script src=""></script>

a: 1
b: 2

Is there a “not in” operator in JavaScript for checking object properties?

As already said by Jordão, just negate it:

if (!(id in tutorTimes)) { ... }

Note: The above test if tutorTimes has a property with the name specified in id, anywhere in the prototype chain. For example "valueOf" in tutorTimes returns true because it is defined in Object.prototype.

If you want to test if a property doesn't exist in the current object, use hasOwnProperty:

if (!tutorTimes.hasOwnProperty(id)) { ... }

Or if you might have a key that is hasOwnPropery you can use this:

if (!,id)) { ... }

Custom Input[type="submit"] style not working with jquerymobile button

jQuery Mobile >= 1.4

Create a custom class, e.g. .custom-btn. Note that to override jQM styles without using !important, CSS hierarchy should be respected. .ui-btn.custom-class or .ui-input-btn.custom-class.

.ui-input-btn.custom-btn {
   border:1px solid red;
   background:url(img.png) repeat-x;

Add a data-wrapper-class to input. The custom class will be added to input wrapping div.

<input type="button" data-wrapper-class="custom-btn">


jQuery Mobile <= 1.3

Input button is wrapped by a DIV with class ui-btn. You need to select that div and the input[type="submit"]. Using !important is essential to override Jquery Mobile styles.


div.ui-btn, input[type="submit"] {
 border:1px solid red !important;
 text-decoration:none !important;
 font-family:helvetica !important;
 color:red !important;
 background:url(../images/btn_hover.png) repeat-x !important;

How do I auto-submit an upload form when a file is selected?

This is my image upload solution, when user selected the file.

HTML part:

<form enctype="multipart/form-data" id="img_form" method="post">
    <input id="img_input" type="file" name="image" accept="image/*">


document.getElementById('img_input').onchange = function () {
function upload() {
    var upload = document.getElementById('img_input');
    var image = upload.files[0];
      type: "POST",
      data: new FormData($('#img_form')[0]),
      cache: false,
      success:function (msg) {}

Strange out of memory issue while loading an image to a Bitmap object

After looking through all the answers, I was surprised to see that no one mentioned the Glide API for handling images. Great library, and abstracts out all the complexity of bitmap management. You can load and resize images quickly with this library and a single line of code.


You can get the repository here:

How to pick a new color for each plotted line within a figure in matplotlib?


color_cycle was deprecated in 1.5 in favor of this generalization:

# cycler is a separate package extracted from matplotlib.
from cycler import cycler
import matplotlib.pyplot as plt

plt.rc('axes', prop_cycle=(cycler('color', ['r', 'g', 'b'])))
plt.plot([1, 2])
plt.plot([2, 3])
plt.plot([3, 4])
plt.plot([4, 5])
plt.plot([5, 6])

Also shown in the (now badly named) example: mentioned at:

Tested in matplotlib 1.5.1.

Importing a csv into mysql via command line

You could do a

mysqlimport --columns='head -n 1 $yourfile' --ignore-lines=1 dbname $yourfile`

That is, if your file is comma separated and is not semi-colon separated. Else you might need to sed through it too.

HTML5 Video // Completely Hide Controls

<video width="320" height="240" autoplay="autoplay">
  <source src="movie.mp4" type="video/mp4">
  <source src="movie.ogg" type="video/ogg">
  Your browser does not support the video tag.

KeyListener, keyPressed versus keyTyped

keyPressed - when the key goes down
keyReleased - when the key comes up
keyTyped - when the unicode character represented by this key is sent by the keyboard to system input.

I personally would use keyReleased for this. It will fire only when they lift their finger up.

Note that keyTyped will only work for something that can be printed (I don't know if F5 can or not) and I believe will fire over and over again if the key is held down. This would be useful for something like... moving a character across the screen or something.

How to solve : SQL Error: ORA-00604: error occurred at recursive SQL level 1

One possible explanation is a database trigger that fires for each DROP TABLE statement. To find the trigger, query the _TRIGGERS dictionary views:

select * from all_triggers
where trigger_type in ('AFTER EVENT', 'BEFORE EVENT')

disable any suspicious trigger with

   alter trigger <trigger_name> disable;

and try re-running your DROP TABLE statement

UIScrollView Scrollable Content Size Ambiguity

What I did is create a separate content view as shown here.

The content view is freeform and can has all subviews added to it with their own constraints in relation to the contentView.

The UIScrollView is added to the main view controller.

Programatically I add the contentView which is linked via IBOutlet to class and set the contentView of UIScrollView.

UIScrollView with ContentView via Interface Builder

How to change the interval time on bootstrap carousel?

You can use the options when initializing the carousel, like this:

// interval is in milliseconds. 1000 = 1 second -> so 1000 * 10 = 10 seconds
  interval: 1000 * 10

or you can use the interval attribute directly on the HTML tag, like this:

<div class="carousel" data-interval="10000">

The advantage of the latter approach is that you do not have to write any JS for it - while the advantage of the former is that you can compute the interval and initialize it with a variable value at run time.

How can I update window.location.hash without jumping the document?

Cheap and nasty solution.. Use the ugly #! style.

To set it:

window.location.hash = '#!' + id;

To read it:

id = window.location.hash.replace(/^#!/, '');

Since it doesn't match and anchor or id in the page, it won't jump.

How to alias a table in Laravel Eloquent queries (or using Query Builder)?

You can use less code, writing this:

    $users = DB::table('really_long_table_name')
       ->get(array('really_long_table_name.field_very_long_name as short_name'));

And of course if you want to select more fields, just write a "," and add more:

 $users = DB::table('really_long_table_name')
       ->get(array('really_long_table_name.field_very_long_name as short_name', 'really_long_table_name.another_field as other', 'and_another'));

This is very practical when you use a joins complex query

Most efficient conversion of ResultSet to JSON?

In addition to suggestions made by @Jim Cook. One other thought is to use a switch instead of if-elses:

while( {
  int numColumns = rsmd.getColumnCount();
  JSONObject obj = new JSONObject();

  for( int i=1; i<numColumns+1; i++) {
    String column_name = rsmd.getColumnName(i);

    switch( rsmd.getColumnType( i ) ) {
      case java.sql.Types.ARRAY:
        obj.put(column_name, rs.getArray(column_name));     break;
      case java.sql.Types.BIGINT:
        obj.put(column_name, rs.getInt(column_name));       break;
      case java.sql.Types.BOOLEAN:
        obj.put(column_name, rs.getBoolean(column_name));   break;
      case java.sql.Types.BLOB:
        obj.put(column_name, rs.getBlob(column_name));      break;
      case java.sql.Types.DOUBLE:
        obj.put(column_name, rs.getDouble(column_name));    break;
      case java.sql.Types.FLOAT:
        obj.put(column_name, rs.getFloat(column_name));     break;
      case java.sql.Types.INTEGER:
        obj.put(column_name, rs.getInt(column_name));       break;
      case java.sql.Types.NVARCHAR:
        obj.put(column_name, rs.getNString(column_name));   break;
      case java.sql.Types.VARCHAR:
        obj.put(column_name, rs.getString(column_name));    break;
      case java.sql.Types.TINYINT:
        obj.put(column_name, rs.getInt(column_name));       break;
      case java.sql.Types.SMALLINT:
        obj.put(column_name, rs.getInt(column_name));       break;
      case java.sql.Types.DATE:
        obj.put(column_name, rs.getDate(column_name));      break;
      case java.sql.Types.TIMESTAMP:
        obj.put(column_name, rs.getTimestamp(column_name)); break;
        obj.put(column_name, rs.getObject(column_name));    break;


How to select rows from a DataFrame based on column values

Faster results can be achieved using numpy.where.

For example, with unubtu's setup -

In [76]: df.iloc[np.where(df.A.values=='foo')]
     A      B  C   D
0  foo    one  0   0
2  foo    two  2   4
4  foo    two  4   8
6  foo    one  6  12
7  foo  three  7  14

Timing comparisons:

In [68]: %timeit df.iloc[np.where(df.A.values=='foo')]  # fastest
1000 loops, best of 3: 380 µs per loop

In [69]: %timeit df.loc[df['A'] == 'foo']
1000 loops, best of 3: 745 µs per loop

In [71]: %timeit df.loc[df['A'].isin(['foo'])]
1000 loops, best of 3: 562 µs per loop

In [72]: %timeit df[df.A=='foo']
1000 loops, best of 3: 796 µs per loop

In [74]: %timeit df.query('(A=="foo")')  # slowest
1000 loops, best of 3: 1.71 ms per loop

How to find out the MySQL root password

This worked for me:

On terminal type the following

$ sudo mysql -u root -p

Enter password://just press enter


How do I specify the platform for MSBuild?

If you're trying to do this from the command line, you may be encountering an issue where a machine-wide environment variable 'Platform' is being set for you and working against you. I can reproduce this if I use the VS2012 Command window instead of a regular windows Command window.

At the command prompt type:

set platform

In a VS2012 Command window, I have a value of 'X64' preset. That seems to interfere with whatever is in my solution file.

In a regular Command window, the 'set' command results in a "variable not defined" message...which is good.

If the result of your 'set' command above returns no environment variable value, you should be good to go.

How to use a variable for the database name in T-SQL?

You can also use sqlcmd mode for this (enable this on the "Query" menu in Management Studio).

:setvar dbname "TEST" 



Check this MSDN article to set parameters via the SQLCMD tool.

grep for multiple strings in file on different lines (ie. whole file, not line based search)?

Here's what worked well for me:

find . -path '*/.svn' -prune -o -type f -exec gawk '/Dansk/{a=1}/Norsk/{b=1}/Svenska/{c=1}END{ if (a && b && c) print FILENAME }' {} \;

If I just wanted to find .sh files with these three, then I could have used:

find . -path '*/.svn' -prune -o -type f -name "*.sh" -exec gawk '/Dansk/{a=1}/Norsk/{b=1}/Svenska/{c=1}END{ if (a && b && c) print FILENAME }' {} \;

PL/SQL print out ref cursor returned by a stored procedure

Note: This code is untested

Define a record for your refCursor return type, call it rec. For example:

TYPE MyRec IS RECORD (col1 VARCHAR2(10), col2 VARCHAR2(20), ...);  --define the record
rec MyRec;        -- instantiate the record

Once you have the refcursor returned from your procedure, you can add the following code where your comments are now:

  FETCH refCursor INTO rec;

How to Get a Specific Column Value from a DataTable?

Datatables have a .Select method, which returns a rows array according to the criteria you specify. Something like this:

Dim oRows() As DataRow

oRows = dtCountries.Select("CountryName = '" & userinput & "'")

If oRows.Count = 0 Then
   ' No rows found
   ' At least one row found. Could be more than one
End If

Of course, if userinput contains ' character, it would raise an exception (like if you query the database). You should escape the ' characters (I use a function to do that).

How can I uninstall npm modules in Node.js?


npm uninstall <package_name>

Example to uninstall express

npm uninstall express

Checking for empty or null JToken in a JObject

Try something like this to convert JToken to JArray:

static public JArray convertToJArray(JToken obj)
    // if ((obj).Type == JTokenType.Null) --> You can check if it's null here

    if ((obj).Type == JTokenType.Array)
        return (JArray)(obj);
        return new JArray(); // this will return an empty JArray

Fetch API request timeout?

I really like the clean approach from this gist using Promise.race


export default function (url, options, timeout = 7000) {
    return Promise.race([
        fetch(url, options),
        new Promise((_, reject) =>
            setTimeout(() => reject(new Error('timeout')), timeout)


import fetch from './fetchWithTimeout'

// call as usual or with timeout as 3rd argument

fetch('', options, 5000) // throw after max 5 seconds timeout error
.then((result) => {
    // handle result
.catch((e) => {
    // handle errors and timeout error

How to Batch Rename Files in a macOS Terminal?

try this

for i in *.png ; do mv "$i" "${i/remove_me*.png/.png}" ; done

Here is another way:

for file in Name*.png; do mv "$file" "01_$file"; done

Using C++ base class constructors?

Prefer initialization:

class C : public A
    C(const string &val) : A(anInt) {}

In C++11, you can use inheriting constructors (which has the syntax seen in your example D).

Update: Inheriting Constructors have been available in GCC since version 4.8.

If you don't find initialization appealing (e.g. due to the number of possibilities in your actual case), then you might favor this approach for some TMP constructs:

class A
    A() {}
    virtual ~A() {}
    void init(int) { std::cout << "A\n"; }

class B : public A
    B() : A() {}
    void init(int) { std::cout << "B\n"; }

class C : public A
    C() : A() {}
    void init(int) { std::cout << "C\n"; }

class D : public A
    D() : A() {}
    using A::init;
    void init(const std::string& s) { std::cout << "D -> " << s << "\n"; }

int main()
    B b; b.init(10);
    C c; c.init(10);
    D d; d.init(10); d.init("a");

    return 0;

Angularjs - ng-cloak/ng-show elements blink

AS from the above discussion

[ng-cloak] {
                display: none;

is the perfect way to solve the Problem.

Accessing post variables using Java Servlets

Your HttpServletRequest object has a getParameter(String paramName) method that can be used to get parameter values.

'and' (boolean) vs '&' (bitwise) - Why difference in behavior with lists vs numpy arrays?

and tests whether both expressions are logically True while & (when used with True/False values) tests if both are True.

In Python, empty built-in objects are typically treated as logically False while non-empty built-ins are logically True. This facilitates the common use case where you want to do something if a list is empty and something else if the list is not. Note that this means that the list [False] is logically True:

>>> if [False]:
...    print 'True'

So in Example 1, the first list is non-empty and therefore logically True, so the truth value of the and is the same as that of the second list. (In our case, the second list is non-empty and therefore logically True, but identifying that would require an unnecessary step of calculation.)

For example 2, lists cannot meaningfully be combined in a bitwise fashion because they can contain arbitrary unlike elements. Things that can be combined bitwise include: Trues and Falses, integers.

NumPy objects, by contrast, support vectorized calculations. That is, they let you perform the same operations on multiple pieces of data.

Example 3 fails because NumPy arrays (of length > 1) have no truth value as this prevents vector-based logic confusion.

Example 4 is simply a vectorized bit and operation.

Bottom Line

  • If you are not dealing with arrays and are not performing math manipulations of integers, you probably want and.

  • If you have vectors of truth values that you wish to combine, use numpy with &.

How do I get NuGet to install/update all the packages in the packages.config?

I tried Update-Package -reinstall but it fails on a package and stopped processing all remaining packages of projects in my solution.

I ended up with my script that enumerates all package.config files and run Update-Package -Reinstall -ProjectName prj -Id pkg for each project/package.

Hope it can be useful for someone:

$files = Get-ChildItem -Recurse -Include packages.config;

[array]$projectPackages = @();
$files | foreach { [xml]$packageFile = gc $_; $projectName = $_.Directory.Name; $ | foreach { $projectPackages += @( ,@( $projectName, $_ ) ) } }

$projectPackages | foreach { Update-Package -Reinstall -ProjectName $_[0] -Id $_[1] }

Edit: This is an error that I had: Update-Package : Unable to find package 'EntityFramework.BulkInsert-ef6'. Existing packages must be restored before performing an install or update. Manual run of Update-Package -Reinstall -ProjectName my_prj -Id EntityFramework.BulkInsert-ef6 worked very well.

jQuery ajax success callback function definition

In your component i.e angular JS code:

function getData(){
    window.location.href = 'http://localhost:1036/api/Employee/GetExcelData';

How to declare an array in Python?

You don't actually declare things, but this is how you create an array in Python:

from array import array
intarray = array('i')

For more info see the array module:

Now possible you don't want an array, but a list, but others have answered that already. :)

Simple and clean way to convert JSON string to Object in Swift

As simple String extension should suffice:

extension String {

    var parseJSONString: AnyObject? {

        let data = self.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)

        if let jsonData = data {
            // Will return an object or nil if JSON decoding fails
            return NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.MutableContainers, error: nil)
        } else {
            // Lossless conversion of the string was not possible
            return nil


var jsonString = "[\n" +
    "{\n" +
    "\"id\":72,\n" +
    "\"name\":\"Batata Cremosa\",\n" +            
    "},\n" +
    "{\n" +
    "\"id\":183,\n" +
    "\"name\":\"Caldeirada de Peixes\",\n" +            
    "},\n" +
    "{\n" +
    "\"id\":76,\n" +
    "\"name\":\"Batata com Cebola e Ervas\",\n" +            
    "},\n" +
    "{\n" +
    "\"id\":56,\n" +
    "\"name\":\"Arroz de forma\",\n" +            

let json: AnyObject? = jsonString.parseJSONString
println("Parsed JSON: \(json!)")
println("json[3]: \(json![3])")

/* Output:

Parsed JSON: (
    id = 72;
    name = "Batata Cremosa";
    id = 183;
    name = "Caldeirada de Peixes";
    id = 76;
    name = "Batata com Cebola e Ervas";
    id = 56;
    name = "Arroz de forma";

json[3]: {
    id = 56;
    name = "Arroz de forma";

Open source PDF library for C/C++ application?

It depends a bit on your needs. Some toolkits are better at drawing, others are better for writing text. Cairo has a pretty good for drawing (it support a wide range of screen and file types, including pdf), but it may not be ideal for good typography.

How to configure nginx to enable kinda 'file browser' mode?

1. List content of all directories

Set autoindex option to on. It is off by default.

Your configuration file ( vi /etc/nginx/sites-available/default ) should be like this

location /{ 
   ... ( some other lines )
   autoindex on;
   ... ( some other lines )

2. List content of only some specific directory

Set autoindex option to on. It is off by default.

Your configuration file ( vi /etc/nginx/sites-available/default )
should be like this.
change path_of_your_directory to your directory path

location /path_of_your_directory{ 
   ... ( some other lines )
   autoindex on;
   ... ( some other lines )

Hope it helps..

How to remove all characters after a specific character in python?

If you want to remove everything after the last occurrence of separator in a string I find this works well:


For example, if string_to_split is a path like root/location/child/too_far.exe and you only want the folder path, you can split by "/".join(string_to_split.split("/")[:-1]) and you'll get root/location/child

How to stop/kill a query in postgresql?

What I did is first check what are the running processes by

SELECT * FROM pg_stat_activity WHERE state = 'active';

Find the process you want to kill, then type:

SELECT pg_cancel_backend(<pid of the process>)

This basically "starts" a request to terminate gracefully, which may be satisfied after some time, though the query comes back immediately.

If the process cannot be killed, try:

SELECT pg_terminate_backend(<pid of the process>)

Format a datetime into a string with milliseconds

@Cabbi raised the issue that on some systems, the microseconds format %f may give "0", so it's not portable to simply chop off the last three characters.

The following code carefully formats a timestamp with milliseconds:

from datetime import datetime
(dt, micro) = datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f').split('.')
dt = "%s.%03d" % (dt, int(micro) / 1000)
print dt

Example Output:

2016-02-26 04:37:53.133

To get the exact output that the OP wanted, we have to strip punctuation characters:

from datetime import datetime
(dt, micro) = datetime.utcnow().strftime('%Y%m%d%H%M%S.%f').split('.')
dt = "%s%03d" % (dt, int(micro) / 1000)
print dt

Example Output:


What is the difference between Scala's case class and class?

The case class construct in Scala can also be seen as a convenience to remove some boilerplate.

When constructing a case class Scala gives you the following.

  • It creates a class as well as its companion object
  • Its companion object implements the apply method that you are able to use as a factory method. You get the syntactic sugar advantage of not having to use the new keyword.

Because the class is immutable you get accessors, which are just the variables (or properties) of the class but no mutators (so no ability to change the variables). The constructor parameters are automatically available to you as public read only fields. Much nicer to use than Java bean construct.

  • You also get hashCode, equals, and toString methods by default and the equals method compares an object structurally. A copy method is generated to be able to clone an object (with some fields having new values provided to the method).

The biggest advantage as has been mentioned previously is the fact that you can pattern match on case classes. The reason for this is because you get the unapply method which lets you deconstruct a case class to extract its fields.

In essence what you are getting from Scala when creating a case class (or a case object if your class takes no arguments) is a singleton object which serves the purpose as a factory and as an extractor .


My understanding is that HEAD points the current branch, while ORIG_HEAD is used to store the previous HEAD before doing "dangerous" operations.

For example git-rebase and git-am record the original tip of branch before they apply any changes.

When to use <span> instead <p>?

p {
    float: left;
    margin: 0;

No spacing will be around, it looks similar to span.

What is VanillaJS?

VanillaJS === JavaScript i.e.VanillaJS is native JavaScript

Why, Vanilla says it all!!!

Computer software, and sometimes also other computing-related systems like computer hardware or algorithms, are called vanilla when not customized from their original form, meaning that they are used without any customization or updates applied to them (Refer this article). So Vanilla often refers to pure or plain.

In the English language Vanilla has a similar meaning, In information technology, vanilla (pronounced vah-NIHL-uh ) is an adjective meaning plain or basic. Or having no special or extra features, ordinary or standard.

So why name it VanillaJS? As the accepted answer says some bosses want to work with a framework (because it's more organized and flexible and do all the things we want??) but simply JavaScript will do the job. Yet you need to add a framework somewhere. Use VanillaJS...

Is it a Joke? YES

Want some fun? Where can you find it, Download and see for yourself!!! It's 0 bytes uncompressed, 25 bytes gzipped :D

Found this pun on internet regarding JS frameworks (Not to condemn the existing JS frameworks though, they'll make life really easy :)), enter image description here

Also refer,

How should I log while using multiprocessing in Python?

There is this great package




pip install multiprocessing-logging

Then add:

import multiprocessing_logging

# This enables logs inside process

What is the difference between <p> and <div>?

It might be better to see the standard designed by Here is the address:

A "DIV" tag can wrap "P" tag whereas, a "P" tag can not wrap "DIV" tag-so far I know this difference. There may be more other differences.

How do I change selected value of select2 dropdown with JqGrid?

// Set up the Select2 control
    ajax: {
        url: '/api/students'

// Fetch the preselected item, and add to the control
var studentSelect = $('#mySelect2');
    type: 'GET',
    url: '/api/students/s/' + studentId
}).then(function (data) {
    // create the option and append to Select2
    var option = new Option(data.full_name,, true, true);

    // manually trigger the `select2:select` event
        type: 'select2:select',
        params: {
            data: data

Font : Select 2 documentation

Show just the current branch in Git

$ git rev-parse --abbrev-ref HEAD

This should work with Git 1.6.3 or newer.

CSS selector for text input fields?

The attribute selectors are often used for inputs. This is the list of attribute selectors:

[title] All elements with the title attribute are selected.

[title=banana] All elements which have the 'banana' value of the title attribute.

[title~=banana] All elements which contain 'banana' in the value of the title attribute.

[title|=banana] All elements which value of the title attribute starts with 'banana'.

[title^=banana] All elements which value of the title attribute begins with 'banana'.

[title$=banana] All elements which value of the title attribute ends with 'banana'.

[title*=banana] All elements which value of the title attribute contains the substring 'banana'.


Bootstrap 4 align navbar items to the right

Find the 69 line in the verndor-prefixes.less and write it following:

.panel {_x000D_
    margin-bottom: 20px;_x000D_
    height: 100px;_x000D_
    background-color: #fff;_x000D_
    border: 1px solid transparent;_x000D_
    border-radius: 4px;_x000D_
    -webkit-box-shadow: 0 1px 1px rgba(0,0,0,.05);_x000D_
    box-shadow: 0 1px 1px rgba(0,0,0,.05);_x000D_

PHP Try and Catch for SQL Insert

if you want to log the error etc you should use try/catch, if you dont; just put @ before mysql_query

edit : you can use try catch like this; so you can log the error and let the page continue to load

function throw_ex($er){  
  throw new Exception($er);  
try {  
$q = mysql_query('select * from asdasda') or throw_ex(mysql_error());  
catch(exception $e) {
  echo "ex: ".$e; 

fatal error LNK1169: one or more multiply defined symbols found in game programming

just add /FORCE as linker flag and you're all set.

for instance, if you're working on CMakeLists.txt. Then add following line:


Display JSON as HTML

I think you meant something like this: JSON Visualization

Don't know if you might use it, but you might ask the author.

Running a cron job at 2:30 AM everyday

As an addition to the all above mentioned great answers, check the - a useful online resource for checking your crontab syntax.

What you get is human readable representation of what you have specified.

See the examples below:

How to enable remote access of mysql in centos?

In case of Allow IP to mysql server linux machine. you can do following command--

 nano /etc/httpd/conf.d/phpMyAdmin.conf  and add Desired IP.

<Directory /usr/share/phpMyAdmin/>
   AddDefaultCharset UTF-8
   Order allow,deny
   allow from all
   <IfModule mod_authz_core.c>
     # Apache 2.4

    Require ip IP)

 <IfModule !mod_authz_core.c>
     # Apache 2.2
     Order Deny,Allow
     #Allow from All

     Allow from IP)


And after Update, please restart using following command--

sudo systemctl restart httpd.service

Call async/await functions in parallel

    // A generic test function that can be configured 
    // with an arbitrary delay and to either resolve or reject
    const test = (delay, resolveSuccessfully) => new Promise((resolve, reject) => setTimeout(() => {
        console.log(`Done ${ delay }`);
        resolveSuccessfully ? resolve(`Resolved ${ delay }`) : reject(`Reject ${ delay }`)
    }, delay));

    // Our async handler function
    const handler = async () => {
        // Promise 1 runs first, but resolves last
        const p1 = test(10000, true);
        // Promise 2 run second, and also resolves
        const p2 = test(5000, true);
        // Promise 3 runs last, but completes first (with a rejection) 
        // Note the catch to trap the error immediately
        const p3 = test(1000, false).catch(e => console.log(e));
        // Await all in parallel
        const r = await Promise.all([p1, p2, p3]);
        // Display the results

    // Run the handler
    Done 1000
    Reject 1000
    Done 5000
    Done 10000

Whilst setting p1, p2 and p3 is not strictly running them in parallel, they do not hold up any execution and you can trap contextual errors with a catch.

Replace whitespaces with tabs in linux

Use the unexpand(1) program

UNEXPAND(1)                      User Commands                     UNEXPAND(1)

       unexpand - convert spaces to tabs

       unexpand [OPTION]... [FILE]...

       Convert  blanks in each FILE to tabs, writing to standard output.  With
       no FILE, or when FILE is -, read standard input.

       Mandatory arguments to long options are  mandatory  for  short  options

       -a, --all
              convert all blanks, instead of just initial blanks

              convert only leading sequences of blanks (overrides -a)

       -t, --tabs=N
              have tabs N characters apart instead of 8 (enables -a)

       -t, --tabs=LIST
              use comma separated LIST of tab positions (enables -a)

       --help display this help and exit

              output version information and exit
. . .
       The expand and unexpand utilities conform to IEEE Std 1003.1-2001

How Connect to remote host from Aptana Studio 3

Window -> Show View -> Other -> Studio/Remote

(Drag this tabbed window wherever)

Click the add FTP button (see below); #profit

Add New FTP Site...

Regular expression for exact match of a string

You may also try appending a space at the start and end of keyword: /\s+123456\s+/i.

Postgres DB Size Command

Based on the answer here by @Hendy Irawan

Show database sizes:



=> \l+
 berbatik_prd_commerce    | berbatik_prd     | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                       | 19 MB   | pg_default | 
 berbatik_stg_commerce    | berbatik_stg     | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                       | 8633 kB | pg_default | 
 bursasajadah_prd         | bursasajadah_prd | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                       | 1122 MB | pg_default | 

Show table sizes:



=> \d+
 public | tuneeca_prd | table | tomcat | 8192 bytes | 
 public | tuneeca_stg | table | tomcat | 1464 kB    | 

Only works in psql.

Regex Until But Not Including

The explicit way of saying "search until X but not including X" is:


where X can be any regular expression.

In your case, though, this might be overkill - here the easiest way would be


This will match anything except z and therefore stop right before the next z.

So .*?quick[^z]* will match The quick fox jumps over the la.

However, as soon as you have more than one simple letter to look out for, (?:(?!X).)* comes into play, for example

(?:(?!lazy).)* - match anything until the start of the word lazy.

This is using a lookahead assertion, more specifically a negative lookahead.

.*?quick(?:(?!lazy).)* will match The quick fox jumps over the.


(?:        # Match the following but do not capture it:
 (?!lazy)  # (first assert that it's not possible to match "lazy" here
 .         # then match any character
)*         # end of group, zero or more repetitions.

Furthermore, when searching for keywords, you might want to surround them with word boundary anchors: \bfox\b will only match the complete word fox but not the fox in foxy.


If the text to be matched can also include linebreaks, you will need to set the "dot matches all" option of your regex engine. Usually, you can achieve that by prepending (?s) to the regex, but that doesn't work in all regex engines (notably JavaScript).

Alternative solution:

In many cases, you can also use a simpler, more readable solution that uses a lazy quantifier. By adding a ? to the * quantifier, it will try to match as few characters as possible from the current position:


will match any number of characters, stopping right before X (which can be any regex) or the end of the string (if X doesn't match). You may also need to set the "dot matches all" option for this to work. (Note: I added a non-capturing group around X in order to reliably isolate it from the alternation)

:touch CSS pseudo-class or something similar?

Since mobile doesn't give hover feedback, I want, as a user, to see instant feedback when a link is tapped. I noticed that -webkit-tap-highlight-color is the fastest to respond (subjective).

Add the following to your body and your links will have a tap effect.

body {
    -webkit-tap-highlight-color: #ccc;

insert vertical divider line between two nested divs, not full height

Can't think of a only css solution, but couldn't you just had a div between those 2 and set in the css the properties to look like a line like shown in the image? If you are using divs as they were table cells this is a pretty simple solution to the problem

How to get a resource id with a known resource name?

// image from res/drawable
    int resID = getResources().getIdentifier("my_image", 
            "drawable", getPackageName());
// view
    int resID = getResources().getIdentifier("my_resource", 
            "id", getPackageName());

// string
    int resID = getResources().getIdentifier("my_string", 
            "string", getPackageName());

How does the modulus operator work?

It gives you the remainder of a division.

int c=11, d=5;
cout << (c/d) * d + c % d; // gives you the value of c

CKEditor automatically strips classes from div

Disabling content filtering

The easiest solution is going to the config.js and setting:

config.allowedContent = true;

(Remember to clear browser's cache). Then CKEditor stops filtering the inputted content at all. However, this will totally disable content filtering which is one of the most important CKEditor features.

Configuring content filtering

You can also configure CKEditor's content filter more precisely to allow only these element, classes, styles and attributes which you need. This solution is much better, because CKEditor will still remove a lot of crappy HTML which browsers produce when copying and pasting content, but it will not strip the content you want.

For example, you can extend the default CKEditor's configuration to accept all div classes:

config.extraAllowedContent = 'div(*)';

Or some Bootstrap stuff:

config.extraAllowedContent = 'div(col-md-*,container-fluid,row)';

Or you can allow description lists with optional dir attributes for dt and dd elements:

config.extraAllowedContent = 'dl; dt dd[dir]';

These were just very basic examples. You can write all kind of rules - requiring attributes, classes or styles, matching only special elements, matching all elements. You can also disallow stuff and totally redefine CKEditor's rules. Read more about:

From milliseconds to hour, minutes, seconds and milliseconds

Just an other java example:

long dayLength = 1000 * 60 * 60 * 24;
long dayMs = System.currentTimeMillis() % dayLength;
double percentOfDay = (double) dayMs / dayLength;
int hour = (int) (percentOfDay * 24);
int minute = (int) (percentOfDay * 24 * 60) % 60;
int second = (int) (percentOfDay * 24 * 60 * 60) % 60;

an advantage is that you can simulate shorter days, if you adjust dayLength

how to attach url link to an image?


<style type="text/css">
#example {
    display: block;
    width: 30px;
    height: 10px;
    background: url(../images/example.png) no-repeat;
    text-indent: -9999px;

<a href="" id="example">See an example!</a>

More wordy, but it may benefit SEO, and it will look like nice simple text with CSS disabled.

Detecting value change of input[type=text] in jQuery

$("#myTextBox").on("change paste keyup select", function() {

select for browser suggestion

NSDictionary to NSArray?

To get all objects in a dictionary, you can also use enumerateKeysAndObjectsUsingBlock: like so:

NSMutableArray *yourArray = [NSMutableArray arrayWithCapacity:6];
[yourDict enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
    [yourArray addObject:obj];

Stretch background image css?

Just paste this into your line of codes:

<meta http-equiv="X-UA-Compatible" content="IE=Edge" />

How to tell if homebrew is installed on Mac OS X

In my case Mac OS High Sierra 10.13.6

brew -v

Homebrew 2.2.2
Homebrew/homebrew-core (git revision 71aa; last commit 2020-01-07)
Homebrew/homebrew-cask (git revision 84f00; last commit 2020-01-07)

Convert Rows to columns using 'Pivot' in SQL Server

This is what you can do:

FROM yourTable
PIVOT (MAX(xCount) 
       FOR Week in ([1],[2],[3],[4],[5],[6],[7])) AS pvt


How to draw circle in html page?

There is not technically a way to draw a circle with HTML (there isn’t a <circle> HTML tag), but a circle can be drawn.

The best way to draw one is to add border-radius: 50% to a tag such as div. Here’s an example:

<div style="width: 50px; height: 50px; border-radius: 50%;">You can put text in here.....</div>

Data truncated for column?

However I get an error which doesn't make sense seeing as the column's data type was properly modified?

| Level | Code | Msg | Warn | 12 | Data truncated for column 'incoming_Cid' at row 1

You can often get this message when you are doing something like the following:

REPLACE INTO table2 (SELECT * FROM table1);

Resulted in our case in the following error:

SQL Exception: Data truncated for column 'level' at row 1

The problem turned out to be column misalignment that resulted in a tinyint trying to be stored in a datetime field or vice versa.

How to sort a list of lists by a specific index of the inner list?

Like this:

import operator
l = [...]
sorted_list = sorted(l, key=operator.itemgetter(desired_item_index))

Convert HH:MM:SS string to seconds only in javascript

You can do this dynamically - in case you encounter not only: HH:mm:ss, but also, mm:ss, or even ss alone.

var str = '12:99:07';
var times = str.split(":");
var x = times.length, y = 0, z;
for (var i = 0; i < x; i++) {
    z = times[i] * Math.pow(60, i);
    y += z;

Javascript document.getElementById("id").value returning null instead of empty string when the element is an empty text box

For your code

var mytextvalue = document.getElementById("mytext");

mytextvalue will contain null if you have a document.write() statement before this code. So remove the document.write statement and you should get a proper text object in the variable mytextvalue.

This is caused by document.write changing the document.

Android Whatsapp/Chat Examples

Check out yowsup

Yowsup is a python library that allows you to do all the previous in your own app. Yowsup allows you to login and use the Whatsapp service and provides you with all capabilities of an official Whatsapp client, allowing you to create a full-fledged custom Whatsapp client.

A solid example of Yowsup's usage is Wazapp. Wazapp is full featured Whatsapp client that is being used by hundreds of thousands of people around the world. Yowsup is born out of the Wazapp project. Before becoming a separate project, it was only the engine powering Wazapp. Now that it matured enough, it was separated into a separate project, allowing anyone to build their own Whatsapp client on top of it. Having such a popular client as Wazapp, built on Yowsup, helped bring the project into a much advanced, stable and mature level, and ensures its continuous development and maintaince.

Yowsup also comes with a cross platform command-line frontend called yowsup-cli. yowsup-cli allows you to jump into connecting and using Whatsapp service directly from command line.

Is it possible to specify proxy credentials in your web.config?

While I haven't found a good way to specify proxy network credentials in the web.config, you might find that you can still use a non-coding solution, by including this in your web.config:

    <defaultProxy useDefaultCredentials="true">
      <proxy proxyaddress="proxyAddress" usesystemdefault="True"/>

The key ingredient in getting this going, is to change the IIS settings, ensuring the account that runs the process has access to the proxy server. If your process is running under LocalService, or NetworkService, then this probably won't work. Chances are, you'll want a domain account.

Convert char * to LPWSTR

The clean way to use mbstowcs is to call it twice to find the length of the result:

  const char * cs = <your input char*>
  size_t wn = mbsrtowcs(NULL, &cs, 0, NULL);

  // error if wn == size_t(-1)

  wchar_t * buf = new wchar_t[wn + 1]();  // value-initialize to 0 (see below)

  wn = mbsrtowcs(buf, &cs, wn + 1, NULL);

  // error if wn == size_t(-1)

  assert(cs == NULL); // successful conversion

  // result now in buf, return e.g. as std::wstring

  delete[] buf;

Don't forget to call setlocale(LC_CTYPE, ""); at the beginning of your program!

The advantage over the Windows MultiByteToWideChar is that this is entirely standard C, although on Windows you might prefer the Windows API function anyway.

I usually wrap this method, along with the opposite one, in two conversion functions string->wstring and wstring->string. If you also add trivial overloads string->string and wstring->wstring, you can easily write code that compiles with the Winapi TCHAR typedef in any setting.

[Edit:] I added zero-initialization to buf, in case you plan to use the C array directly. I would usually return the result as std::wstring(buf, wn), though, but do beware if you plan on using C-style null-terminated arrays.[/]

In a multithreaded environment you should pass a thread-local conversion state to the function as its final (currently invisible) parameter.

Here is a small rant of mine on this topic.

How to vertically center content with variable height within a div?

Just add

position: relative;
top: 50%;
transform: translateY(-50%);

to the inner div.

What it does is moving the inner div's top border to the half height of the outer div (top: 50%;) and then the inner div up by half its height (transform: translateY(-50%)). This will work with position: absolute or relative.

Keep in mind that transform and translate have vendor prefixes which are not included for simplicity.


android edittext onchange listener

The Watcher method fires on every character input. So, I built this code based on onFocusChange method:

public static boolean comS(String s1,String s2){
    if (s1.length()==s2.length()){
        int l=s1.length();
        for (int i=0;i<l;i++){
            if (s1.charAt(i)!=s2.charAt(i))return false;
        return true;
    return false;

public void onChange(final EditText EdTe, final Runnable FRun){
    class finalS{String s="";}
    final finalS dat=new finalS();  
    EdTe.setOnFocusChangeListener(new OnFocusChangeListener() {          
        public void onFocusChange(View v, boolean hasFocus) {
            if (hasFocus) {dat.s=""+EdTe.getText();}
            else if (!comS(dat.s,""+EdTe.getText())){(new Handler()).post(FRun);}       

To using it, just call like this:

onChange(YourEditText, new Runnable(){public void run(){
    // V  V    YOUR WORK HERE


You can ignore the comS function by replace the !comS(dat.s,""+EdTe.getText()) with !equal function. However the equal function itself some time work not correctly in run time.

The onChange listener will remember old data of EditText when user focus typing, and then compare the new data when user lose focus or jump to other input. If comparing old String not same new String, it fires the work.

If you only have 1 EditText, then u will need to make a ClearFocus function by making an Ultimate Secret Transparent Micro EditText outside the windows and request focus to it, then hide the keyboard via Import Method Manager.

Identify duplicates in a List

I took Sebastian's answer and added a keyExtractor to it -

    private <U, T> Set<T> findDuplicates(Collection<T> collection, Function<? super T,? extends U> keyExtractor) {
        Map<U, T> uniques = new HashMap<>(); // maps unique keys to corresponding values
            .filter(e -> uniques.put(keyExtractor.apply(e), e) != null)

How to create a pulse effect using -webkit-animation - outward rings

Or if you want a ripple pulse effect, you could use this:

.gps_ring {
     border: 2px solid #fff;
     -webkit-border-radius: 50%;
     height: 18px;
     width: 18px;
     position: absolute;
    -webkit-animation: pulsate 1s ease-out;
    -webkit-animation-iteration-count: infinite; 
    opacity: 0.0;
.gps_ring:before {
    border: 2px solid #fff;
    -webkit-border-radius: 50%;
    height: 30px;
    width: 30px;
    position: absolute;
    -webkit-animation: pulsate 1s ease-out;
    -webkit-animation-iteration-count: infinite; 
    -webkit-animation-delay: 0.1s;
    opacity: 0.0;
.gps_ring:after {
    border:2px solid #fff;
    -webkit-border-radius: 50%;
    height: 50px;
    width: 50px;
    position: absolute;
    -webkit-animation: pulsate 1s ease-out;
    -webkit-animation-iteration-count: infinite; 
    -webkit-animation-delay: 0.2s;
    opacity: 0.0;
@-webkit-keyframes pulsate {
    0% {-webkit-transform: scale(0.1, 0.1); opacity: 0.0;}
    50% {opacity: 1.0;}
    100% {-webkit-transform: scale(1.2, 1.2); opacity: 0.0;}

Python Pandas : group by in group by and average?

If you want to first take mean on the combination of ['cluster', 'org'] and then take mean on cluster groups, you can use:

In [59]: (df.groupby(['cluster', 'org'], as_index=False).mean()
1          15
2          54
3           6
Name: time, dtype: int64

If you want the mean of cluster groups only, then you can use:

In [58]: df.groupby(['cluster']).mean()
1        12.333333
2        54.000000
3         6.000000

You can also use groupby on ['cluster', 'org'] and then use mean():

In [57]: df.groupby(['cluster', 'org']).mean()
cluster org
1       a    438886
        c        23
2       d      9874
        h        34
3       w         6

Find out where MySQL is installed on Mac OS X

It will be found in /usr/local/mysql if you use the mysql binaries or dmg to install it on your system instead of using MAMP

Angular2 disable button

I would recommend the following.

<button [disabled]="isInvalid()">Submit</button>