Programs & Examples On #Ready

Calling a function when ng-repeat has finished

var module = angular.module('testApp', [])
    .directive('onFinishRender', function ($timeout) {
    return {
        restrict: 'A',
        link: function (scope, element, attr) {
            if (scope.$last === true) {
                $timeout(function () {

Notice that I didn't use .ready() but rather wrapped it in a $timeout. $timeout makes sure it's executed when the ng-repeated elements have REALLY finished rendering (because the $timeout will execute at the end of the current digest cycle -- and it will also call $apply internally, unlike setTimeout). So after the ng-repeat has finished, we use $emit to emit an event to outer scopes (sibling and parent scopes).

And then in your controller, you can catch it with $on:

$scope.$on('ngRepeatFinished', function(ngRepeatFinishedEvent) {
    //you also get the actual event object
    //do stuff, execute functions -- whatever...

With html that looks something like this:

<div ng-repeat="item in items" on-finish-render="ngRepeatFinished">

How to zip a whole folder using PHP

Use this is working fine.

$dir = '/Folder/';
$zip = new ZipArchive();
$res = $zip->open(trim($dir, "/") . '.zip', ZipArchive::CREATE | ZipArchive::OVERWRITE);
if ($res === TRUE) {
    foreach (glob($dir . '*') as $file) {
        $zip->addFile($file, basename($file));
} else {
    echo 'Failed to create to zip. Error: ' . $res;

Blocks and yields in Ruby

I found this article to be very useful. In particular, the following example:


def test
  yield 5
  puts "You are in the method test"
  yield 100

test {|i| puts "You are in the block #{i}"}

test do |i|
    puts "You are in the block #{i}"

which should give the following output:

You are in the block 5
You are in the method test
You are in the block 100
You are in the block 5
You are in the method test
You are in the block 100

So essentially each time a call is made to yield ruby will run the code in the do block or inside {}. If a parameter is provided to yield then this will be provided as a parameter to the do block.

For me, this was the first time that I understood really what the do blocks were doing. It is basically a way for the function to give access to internal data structures, be that for iteration or for configuration of the function.

So when in rails you write the following:

respond_to do |format|
  format.html { render template: "my/view", layout: 'my_layout' }

This will run the respond_to function which yields the do block with the (internal) format parameter. You then call the .html function on this internal variable which in turn yields the code block to run the render command. Note that .html will only yield if it is the file format requested. (technicality: these functions actually use not yield as you can see from the source but the functionality is essentially the same, see this question for a discussion.) This provides a way for the function to perform some initialisation then take input from the calling code and then carry on processing if required.

Or put another way, it's similar to a function taking an anonymous function as an argument and then calling it in javascript.

Jquery in React is not defined

I just want to receive ajax request, but the problem is that jQuery is not defined in React.

Then don't use it. Use Fetch and have a look at Fetch polyfill in React not completely working in IE 11 to see example of alternative ways to get it running

Something like this

const that = this; 
  .then(function(response) { return response.json(); }) 
  .then(function(myJson) { 
     that.setState({data: myJson}); // for example

How to get json key and value in javascript?

var data = {"name": "", "skills": "", "jobtitel": "Entwickler", "res_linkedin": "GwebSearch"}

var parsedData = JSON.parse(data);

How to pass the password to su/sudo/ssh without overriding the TTY?

When there's no better choice (as suggested by others), then man socat can help:

   (sleep 5; echo PASSWORD; sleep 5; echo ls; sleep 1) |
   socat - EXEC:'ssh -l user server',pty,setsid,ctty

          EXEC’utes an ssh session to server. Uses a pty for communication
          between socat and ssh, makes it ssh’s  controlling  tty  (ctty),
          and makes this pty the owner of a new process group (setsid), so
          ssh accepts the password from socat.

All of the pty,setsid,ctty complexity is necessary and, while you might not need to sleep as long, you will need to sleep. The echo=0 option is worth a look too, as is passing the remote command on ssh's command line.

Facebook how to check if user has liked page and show content?

There is an article here that describes your problem

       Fans will see this content.
           Non-fans will see this content.

Trigger a button click with JavaScript on the Enter key in a text box

These day the change event is the way!

    () => document.getElementById("btnSearch").click()

Hive: how to show all partitions of a table?

CLI has some limit when ouput is displayed. I suggest to export output into local file:

$hive -e 'show partitions table;' > partitions

What does question mark and dot operator ?. mean in C# 6.0?

It's the null conditional operator. It basically means:

"Evaluate the first operand; if that's null, stop, with a result of null. Otherwise, evaluate the second operand (as a member access of the first operand)."

In your example, the point is that if a is null, then a?.PropertyOfA will evaluate to null rather than throwing an exception - it will then compare that null reference with foo (using string's == overload), find they're not equal and execution will go into the body of the if statement.

In other words, it's like this:

string bar = (a == null ? null : a.PropertyOfA);
if (bar != foo)

... except that a is only evaluated once.

Note that this can change the type of the expression, too. For example, consider FileInfo.Length. That's a property of type long, but if you use it with the null conditional operator, you end up with an expression of type long?:

FileInfo fi = ...; // fi could be null
long? length = fi?.Length; // If fi is null, length will be null

How to make a form close when pressing the escape key?

Button cancelBTN = new Button();
cancelBTN.Size = new Size(0, 0);
cancelBTN.TabStop = false;
this.CancelButton = cancelBTN;

How to get column by number in Pandas?

Another way is to select a column with the columns array:

In [5]: df = pd.DataFrame([[1,2], [3,4]], columns=['a', 'b'])

In [6]: df
   a  b
0  1  2
1  3  4

In [7]: df[df.columns[0]]
0    1
1    3
Name: a, dtype: int64

Getting byte array through input type = file


As noted in comments above, while still on some UA implementations, readAsBinaryString method didn't made its way to the specs and should not be used in production. Instead, use readAsArrayBuffer and loop through it's buffer to get back the binary string :

document.querySelector('input').addEventListener('change', function() {_x000D_
  var reader = new FileReader();_x000D_
  reader.onload = function() {_x000D_
    var arrayBuffer = this.result,_x000D_
      array = new Uint8Array(arrayBuffer),_x000D_
      binaryString = String.fromCharCode.apply(null, array);_x000D_
}, false);
<input type="file" />_x000D_
<div id="result"></div>

For a more robust way to convert your arrayBuffer in binary string, you can refer to this answer.

[old answer] (modified)

Yes, the file API does provide a way to convert your File, in the <input type="file"/> to a binary string, thanks to the FileReader Object and its method readAsBinaryString.
[But don't use it in production !]

document.querySelector('input').addEventListener('change', function(){_x000D_
    var reader = new FileReader();_x000D_
    reader.onload = function(){_x000D_
        var binaryString = this.result;_x000D_
        document.querySelector('#result').innerHTML = binaryString;_x000D_
  }, false);
<input type="file"/>_x000D_
<div id="result"></div>

If you want an array buffer, then you can use the readAsArrayBuffer() method :

document.querySelector('input').addEventListener('change', function(){_x000D_
    var reader = new FileReader();_x000D_
    reader.onload = function(){_x000D_
        var arrayBuffer = this.result;_x000D_
        document.querySelector('#result').innerHTML = arrayBuffer + '  '+arrayBuffer.byteLength;_x000D_
  }, false);
<input type="file"/>_x000D_
<div id="result"></div>

self.tableView.reloadData() not working in Swift

You must reload your TableView in main thread only. Otherwise your app will be crashed or will be updated after some time. For every UI update it is recommended to use main thread.

//To update UI only this below code is enough
//If you want to do changes in UI use this
DispatchQueue.main.async(execute: {
    //Update UI
    self.tableView.reloadData()//Your tableView here

//Perform some task and update UI immediately. .userInitiated).async {  
    // Call your function here
    DispatchQueue.main.async {  
        // Update UI

//To call or execute function after some time and update UI
DispatchQueue.main.asyncAfter(deadline: .now() + 5.0) {
    //Here call your function
    //If you want to do changes in UI use this
    DispatchQueue.main.async(execute: {
        //Update UI

Text-decoration: none not working

As a sidenote, have in mind that in other cases a codebase might use a border-bottom css attribute, for example border-bottom: 1px;, that creates an effect very similar to the text-decoration: underline. In that case make sure that you set it to none, border-bottom: none;

Android : Fill Spinner From Java Code Programmatically

// you need to have a list of data that you want the spinner to display
List<String> spinnerArray =  new ArrayList<String>();

ArrayAdapter<String> adapter = new ArrayAdapter<String>(
    this, android.R.layout.simple_spinner_item, spinnerArray);

Spinner sItems = (Spinner) findViewById(;

also to find out what is selected you could do something like this

String selected = sItems.getSelectedItem().toString();
if (selected.equals("what ever the option was")) {

How to make for loops in Java increase by increments other than 1

Simply try this

for(int i=0; i<5; i=i+2){//value increased by 2


for(int i=0; i<5; i+=2){//value increased by 2

Display a view from another controller in ASP.NET MVC

Yes its possible. Return a RedirectToAction() method like this:

return RedirectToAction("ActionOrViewName", "ControllerName");

Change the icon of the exe file generated from Visual Studio 2010

To specify an application icon

  1. In Solution Explorer, choose a project node (not the Solution node).
  2. On the menu bar, choose Project, Properties.
  3. When the Project Designer appears, choose the Application tab.
  4. In the Icon list, choose an icon (.ico) file.

To specify an application icon and add it to your project

  1. In Solution Explorer, choose a project node (not the Solution node).
  2. On the menu bar, choose Project, Properties.
  3. When the Project Designer appears, choose the Application tab.
  4. Near the Icon list, choose the button, and then browse to the location of the icon file that you want.

The icon file is added to your project as a content file.

reference : for details see here

PHP Fatal error: Class 'PDO' not found

Ensure they are being called in the php.ini file

If the PDO is displayed in the list of currently installed php modules, you will want to check the php.ini file in the relevant folder to ensure they are being called. Somewhere in the php.ini file you should see the following:

If they are not present, simply add the lines above to the bottom of the php.ini file and save it.

How to compare variables to undefined, if I don’t know whether they exist?

!undefined is true in javascript, so if you want to know whether your variable or object is undefined and want to take actions, you could do something like this:

if(<object or variable>) {
     //take actions if object is not undefined
} else {
     //take actions if object is undefined

Transmitting newline character "\n"

Use %0A (URL encoding) instead of \n (C encoding).

When does Git refresh the list of remote branches?

Use git fetch to fetch all latest created branches.

What is the difference between <html lang="en"> and <html lang="en-US">?

XML Schema requires that the xml namespace be declared and imported before using xml:lang (and other xml namespace values) RELAX NG predeclares the xml namespace, as in XML, so no additional declaration is needed.

How to add a new line of text to an existing file in Java?

You can use the FileWriter(String fileName, boolean append) constructor if you want to append data to file.

Change your code to this:

output = new BufferedWriter(new FileWriter(my_file_name, true));

From FileWriter javadoc:

Constructs a FileWriter object given a file name. If the second argument is true, then bytes will be written to the end of the file rather than the beginning.

How can I add 1 day to current date?

If you want add a day (24 hours) to current datetime you can add milliseconds like this:

new Date( + ( 3600 * 1000 * 24))

How do I properly force a Git push?

Just do:

git push origin <your_branch_name> --force

or if you have a specific repo:

git push https://git.... --force

This will delete your previous commit(s) and push your current one.

It may not be proper, but if anyone stumbles upon this page, thought they might want a simple solution...

Short flag

Also note that -f is short for --force, so

git push origin <your_branch_name> -f

will also work.

Best way to clear a PHP array's values

Sadly I can't answer the other questions, don't have enough reputation, but I need to point something out that was VERY important for me, and I think it will help other people too.

Unsetting the variable is a nice way, unless you need the reference of the original array!

To make clear what I mean: If you have a function wich uses the reference of the array, for example a sorting function like

function special_sort_my_array(&$array)
    $temporary_list = create_assoziative_special_list_out_of_array($array);


    foreach($temporary_list as $k => $v)
        $array[$k] = $v;

it is not working! Be careful here, unset deletes the reference, so the variable $array is created again and filled correctly, but the values are not accessable from outside the function.

So if you have references, you need to use $array = array() instead of unset, even if it is less clean and understandable.

Class 'App\Http\Controllers\DB' not found and I also cannot use a new Model

Try Like this:


    namespace App\Http\Controllers;

    use Illuminate\Http\Request;

    use DB;

    class UserController extends Controller

    function  index(){

    $users = DB::table('users')->get();

    foreach ($users as $user)



Call javascript from MVC controller action

Since your controller actions execute on the server, and JavaScript (usually) executes on the client (browser), this doesn't make sense. If you need some action to happen by default once the page is loaded into the browser, you can use JavaScript's document.OnLoad event handler.

How many files can I put in a directory?

It depends a bit on the specific filesystem in use on the Linux server. Nowadays the default is ext3 with dir_index, which makes searching large directories very fast.

So speed shouldn't be an issue, other than the one you already noted, which is that listings will take longer.

There is a limit to the total number of files in one directory. I seem to remember it definitely working up to 32000 files.

Are string.Equals() and == operator really same?

The Header property of the TreeViewItem is statically typed to be of type object.

Therefore the == yields false. You can reproduce this with the following simple snippet:

object s1 = "Hallo";

// don't use a string literal to avoid interning
string s2 = new string(new char[] { 'H', 'a', 'l', 'l', 'o' });

bool equals = s1 == s2;         // equals is false
equals = string.Equals(s1, s2); // equals is true

How do I POST a x-www-form-urlencoded request using Fetch?

You have to put together the x-www-form-urlencoded payload yourself, like this:

var details = {
    'userName': '[email protected]',
    'password': 'Password!',
    'grant_type': 'password'

var formBody = [];
for (var property in details) {
  var encodedKey = encodeURIComponent(property);
  var encodedValue = encodeURIComponent(details[property]);
  formBody.push(encodedKey + "=" + encodedValue);
formBody = formBody.join("&");

fetch('', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8'
  body: formBody

Note that if you were using fetch in a (sufficiently modern) browser, instead of React Native, you could instead create a URLSearchParams object and use that as the body, since the Fetch Standard states that if the body is a URLSearchParams object then it should be serialised as application/x-www-form-urlencoded. However, you can't do this in React Native because React Native does not implement URLSearchParams.

Find most frequent value in SQL column

SELECT       `column`,
             COUNT(`column`) AS `value_occurrence` 
    FROM     `my_table`
    GROUP BY `column`
    ORDER BY `value_occurrence` DESC
    LIMIT    1;

Replace column and my_table. Increase 1 if you want to see the N most common values of the column.

Know relationships between all the tables of database in SQL Server

My solution is based on @marc_s solution, i just concatenated columns in cases that a constraint is based on more than one column:

   FK.[name] AS ForeignKeyConstraintName
  ,SCHEMA_NAME(FT.schema_id) + '.' + FT.[name] AS ForeignTable
  ,STUFF(ForeignColumns.ForeignColumns, 1, 2, '') AS ForeignColumns
  ,SCHEMA_NAME(RT.schema_id) + '.' + RT.[name] AS ReferencedTable
  ,STUFF(ReferencedColumns.ReferencedColumns, 1, 2, '') AS ReferencedColumns
  sys.foreign_keys FK
  INNER JOIN sys.tables FT
  ON FT.object_id = FK.parent_object_id
  INNER JOIN sys.tables RT
  ON RT.object_id = FK.referenced_object_id
      ', ' + iFC.[name] AS [text()]
      sys.foreign_key_columns iFKC
      INNER JOIN sys.columns iFC
      ON iFC.object_id = iFKC.parent_object_id
        AND iFC.column_id = iFKC.parent_column_id
      iFKC.constraint_object_id = FK.object_id
    FOR XML PATH('')
  ) ForeignColumns (ForeignColumns)
      ', ' + iRC.[name]AS [text()]
      sys.foreign_key_columns iFKC
      INNER JOIN sys.columns iRC
      ON iRC.object_id = iFKC.referenced_object_id
        AND iRC.column_id = iFKC.referenced_column_id
      iFKC.constraint_object_id = FK.object_id
    FOR XML PATH('')
  ) ReferencedColumns (ReferencedColumns)

Column calculated from another column?

I hope this still helps someone as many people might get to this article. If you need a computed column, why not just expose your desired columns in a view ? Don't just save data or overload the performance with triggers... simply expose the data you need already formatted/calculated in a view.

Hope this helps...

How different is Scrum practice from Agile Practice?

Agile is commonly regarded as an umbrella term. Scrum/Kanban are executions of Agile guiding principles from a project management perspective, whereas eXtreme Programming (XP) focuses on the engineering practices e.g., Unit Testing, Continuous Integration, Pair Programming etc.

Typically: Agile = Scrum + XP

How to use performSelector:withObject:afterDelay: with primitive types in Cocoa?


There is a simple trick if it is a BOOL parameter.

Pass nil for NO and self for YES. nil is cast to the BOOL value of NO. self is cast to the BOOL value of YES.

This approach breaks down if it is anything other than a BOOL parameter.

Assuming self is a UIView.

//nil will be cast to NO when the selector is performed
[self performSelector:@selector(setHidden:) withObject:nil afterDelay:5.0];

//self will be cast to YES when the selector is performed
[self performSelector:@selector(setHidden:) withObject:self afterDelay:10.0];

Android setOnClickListener method - How does it work?

It works by same principle of anonymous inner class where we can instantiate an interface without actually defining a class :


Transfer files to/from session I'm logged in with PuTTY

There's no way to initiate a file transfer back to/from local Windows from a SSH session opened in PuTTY window.

Though PuTTY supports connection-sharing.

While you still need to run a compatible file transfer client (the pscp or psftp), no new login is required, it automatically (if enabled) makes use of an existing PuTTY session.

To enable the sharing see:
Sharing an SSH connection between PuTTY tools.

Alternative way is to use WinSCP, a GUI SFTP/SCP client. While you browse the remote site, you can anytime open SSH terminal to the same site using Open in PuTTY button.

See Opening Session in PuTTY.

With an additional setup, you can even make PuTTY automatically navigate to the same directory you are browsing with WinSCP.

See Opening PuTTY in the Same Directory.

(I'm the author of WinSCP)

Overlaying histograms with ggplot2 in R

Your current code:

ggplot(histogram, aes(f0, fill = utt)) + geom_histogram(alpha = 0.2)

is telling ggplot to construct one histogram using all the values in f0 and then color the bars of this single histogram according to the variable utt.

What you want instead is to create three separate histograms, with alpha blending so that they are visible through each other. So you probably want to use three separate calls to geom_histogram, where each one gets it's own data frame and fill:

ggplot(histogram, aes(f0)) + 
    geom_histogram(data = lowf0, fill = "red", alpha = 0.2) + 
    geom_histogram(data = mediumf0, fill = "blue", alpha = 0.2) +
    geom_histogram(data = highf0, fill = "green", alpha = 0.2) +

Here's a concrete example with some output:

dat <- data.frame(xx = c(runif(100,20,50),runif(100,40,80),runif(100,0,30)),yy = rep(letters[1:3],each = 100))

ggplot(dat,aes(x=xx)) + 
    geom_histogram(data=subset(dat,yy == 'a'),fill = "red", alpha = 0.2) +
    geom_histogram(data=subset(dat,yy == 'b'),fill = "blue", alpha = 0.2) +
    geom_histogram(data=subset(dat,yy == 'c'),fill = "green", alpha = 0.2)

which produces something like this:

enter image description here

Edited to fix typos; you wanted fill, not colour.

Android: Vertical alignment for multi line EditText (Text area)

Now a day use of gravity start is best choise:


For EditText (textarea):


'No JUnit tests found' in Eclipse

I had the same problem and solved like this: I deleted @Test annotation and retyped it. It just worked, I have no idea why.

Base table or view not found: 1146 Table Laravel 5

I faced this problem too in laravel 5.2 and if declaring the table name doesn't work,it is probably because you have some wrong declaration or mistake in validation code in Request (If you are using one)

Failed to load resource: the server responded with a status of 404 (Not Found) error in server

Use your browser's network inspector (F12) to see when the browser is requesting the bgbody.png image and what absolute path it's using and why the server is returning a 404 response.

...assuming that bgbody.png actually exists :)

Is your CSS in a stylesheet file or in a <style> block in a page? If it's in a stylesheet then the relative path must be relative to the CSS stylesheet (not the document that references it). If it's in a page then it must be relative to the current resource path. If you're using non-filesystem-based resource paths (i.e. using URL rewriting or URL routing) then this will cause problems and it's best to always use absolute paths.

Going by your relative path it looks like you store your images separately from your stylesheets. I don't think this is a good idea - I support storing images and other resources, like fonts, in the same directory as the stylesheet itself, as it simplifies paths and is also a more logical filesystem arrangement.

What's "tools:context" in Android layout files?

This attribute helps to get the best knowledge of the activity associated with your layout. This is also useful when you have to add onClick handlers on a view using QuickFix.


Why can't I define my workbook as an object?

It's actually a sensible question. Here's the answer from Excel 2010 help:

"The Workbook object is a member of the Workbooks collection. The Workbooks collection contains all the Workbook objects currently open in Microsoft Excel."

So, since that workbook isn't open - at least I assume it isn't - it can't be set as a workbook object. If it was open you'd just set it like:

Set wbk = workbooks("Master Benchmark Data Sheet.xlsx")

How to determine the current iPhone/device model?

struct DeviceType {
        static let IS_IPHONE_4_OR_LESS = UIDevice.current.userInterfaceIdiom == .phone && Constants.SCREEN_MAX_LENGTH < 568
        static let IS_IPHONE_5 = UIDevice.current.userInterfaceIdiom == .phone && Constants.SCREEN_MAX_LENGTH == 568
        static let IS_IPHONE_6 = UIDevice.current.userInterfaceIdiom == .phone && Constants.SCREEN_MAX_LENGTH == 667
        static let IS_IPHONE_6P = UIDevice.current.userInterfaceIdiom == .phone && Constants.SCREEN_MAX_LENGTH == 736
        static let IS_IPAD = UIDevice.current.userInterfaceIdiom == .pad && Constants.SCREEN_MAX_LENGTH == 1024

How to create directory automatically on SD card

Don't forget to make sure that you have no special characters in your file/folder names. Happened to me with ":" when I was setting folder names using variable(s)

not allowed characters in file/folder names

" * / : < > ? \ |

U may find this code helpful in such a case.

The below code removes all ":" and replaces them with "-"

//actualFileName = "qwerty:asdfg:zxcvb" say...

    String[] tempFileNames;
    String tempFileName ="";
    String delimiter = ":";
    tempFileNames = actualFileName.split(delimiter);
    tempFileName = tempFileNames[0];
    for (int j = 1; j < tempFileNames.length; j++){
        tempFileName = tempFileName+" - "+tempFileNames[j];
    File file = new File(Environment.getExternalStorageDirectory(), "/MyApp/"+ tempFileName+ "/");
    if (!file.exists()) {
        if (!file.mkdirs()) {
        Log.e("TravellerLog :: ", "Problem creating Image folder");

"Debug certificate expired" error in Eclipse Android plugins

First close the eclipse then

Open CMD by Window Key + R or via Run as Admin

Follows the following step

del "%USERPROFILE%\.android\debug.keystore"
keytool -genkey -v -keystore "%USERPROFILE%\.android\debug.keystore" -alias androiddebugkey -storepass android -keypass android -keyalg RSA -validity 30000

after this restart eclipse.

How to set a Default Route (To an Area) in MVC

Well, while creating a custom view engine can work for this, still you can have an alternative:

  • Decide what you need to show by default.
  • That something has controller and action (and Area), right?
  • Open that Area registration and add something like this:
public override void RegisterArea(AreaRegistrationContext context)
    //this makes it work for the empty url (just domain) to act as current Area.
        new { controller = "Home", action = "Index", id = UrlParameter.Optional },
        namespaces: new string[] { "Area controller namespace" }
        //other routes of the area


Python: Converting from ISO-8859-1/latin1 to UTF-8

Decode to Unicode, encode the results to UTF8.


Bash Templating: How to build configuration files from templates with Bash?

Instead of reinventing the wheel go with envsubst Can be used in almost any scenario, for instance building configuration files from environment variables in docker containers.

If on mac make sure you have homebrew then link it from gettext:

brew install gettext
brew link --force gettext


# We put env variables into placeholders here
this_variable_1 = ${SOME_VARIABLE_1}
this_variable_2 = ${SOME_VARIABLE_2}




cat template.cfg | envsubst > whatever.cfg

Now just use it:

# make script executable
chmod +x ./
# source your variables
. .env
# export your variables
# In practice you may not have to manually export variables 
# if your solution depends on tools that utilise .env file 
# automatically like pipenv etc. 
# Create your config file

Swift Error: Editor placeholder in source file

If you have this error while you create segues with the view controllers not with the UI elements you have to change sender: Any? to this

@IBAction func backButtonPressed(_ sender: Any) {
        performSegue(withIdentifier: "goToMainScreen", sender: self)


It will work.

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

    protected void Application_EndRequest()
        if (Context.Response.StatusCode == 405 && Context.Request.HttpMethod == "OPTIONS" )
            Response.StatusCode = 200;

Add multiple items to a list

Thanks to AddRange:


public class Person
    private string Name;
    private string FirstName;

    public Person(string name, string firstname) => (Name, FirstName) = (name, firstname);

To add multiple Person to a List<>:

List<Person> listofPersons = new List<Person>();
listofPersons.AddRange(new List<Person>
    new Person("John1", "Doe" ),
    new Person("John2", "Doe" ),
    new Person("John3", "Doe" ),

Apache could not be started - ServerRoot must be a valid directory and Unable to find the specified module

  1. Navigate to your XAMPP directory, you will find a folder called apache, open it, then copy its path, my path is "D:\Hacking Tools 2\Programs\XAMPP V2\apache"
  2. Open up apache\conf\httpd.conf with any text editor
  3. Scroll down until line 30-40
  4. You will find a code like this: ServerRoot "xampp\apache"
  5. Now, change it to be the apache directory, as I said in Step #1, my path is "D:\Hacking Tools 2\Programs\XAMPP V2\apache", so, my code will be ServerRoot "D:\Hacking Tools 2\Programs\XAMPP V2\apache"
  6. It should look somehow like this: ServerRoot "D:\XAMPP\apache"
  7. Now go back to the XAMPP main directory and run xampp_start.exe

It worked for me, if it doesn't work for you, just comment with the error value after opening the xampp_start.exe

UnicodeEncodeError: 'ascii' codec can't encode character at special name

Try setting the system default encoding as utf-8 at the start of the script, so that all strings are encoded using that.

Example -

import sys

The above should set the default encoding as utf-8 .

Android REST client, Sample?

We have open-sourced our lightweight async REST client library for Android, you might find it useful if you have minimal requirements and don't want to handle the multithreading yourself - it is very OK for basic communications but not a full-blown REST client library.

It's called libRESTfulClient and can be found on GitHub.

How to scroll up or down the page to an anchor using jQuery?

You should also consider that the target has a padding and thus use position instead of offset. You can also account for a potential nav bar you don't want to be overlapping the target.

const $navbar = $('.navbar');

$('a[href^="#"]').on('click', function(e) {

    const scrollTop =
        $($(this).attr('href')).position().top -

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

Maintain the aspect ratio of a div with CSS

Elliot inspired me to this solution - thanks:

aspectratio.png is a completely transparent PNG-file with the size of your preferred aspect-ratio, in my case 30x10 pixels.


<div class="eyecatcher">
  <img src="/img/aspectratio.png"/>


.eyecatcher img {
  width: 100%;
  background-repeat: no-repeat;
  background-size: 100% 100%;
  background-image: url(../img/autoresized-picture.jpg);

Please note: background-size is a css3-feature which might not work with your target-browsers. You may check interoperability (f.e. on

How to make --no-ri --no-rdoc the default for gem install?

On Windows XP the path to the .gemrc file is

c:\Documents and Settings\All Users\Application Data\gemrc 

and this file is not created by default, you should create it yourself.

"No such file or directory" error when executing a binary

You get this error when you try to run a 32-bit build on your 64-bit Linux.

Also contrast what file had to say on the binary you tried (ie: 32-bit) with what you get for your /bin/gzip:

$ file /bin/gzip
/bin/gzip: ELF 64-bit LSB executable, x64-64, version 1 (SYSV), \
dynamically linked (uses shared libs), for GNU/Linux 2.6.15, stripped

which is what I get on Ubuntu 9.10 for amd64 aka x86_64.

Edit: Your expanded post shows that as the readelf output also reflects a 32-bit build.

How do I make a checkbox required on an ASP.NET form?

C# version of andrew's answer:

<asp:CustomValidator ID="CustomValidator1" runat="server" 
        ErrorMessage="Please accept the terms..." 
    <asp:CheckBox ID="CheckBox1" runat="server" />


protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
    args.IsValid = CheckBox1.Checked;

How to resize Twitter Bootstrap modal dynamically based on the content

You can do that if you use jquery dialog plugin from and set the width to auto.

  uiLibrary: 'bootstrap',_x000D_
  width: 'auto'_x000D_
  <script src=""></script>_x000D_
  <link href="" rel="stylesheet" type="text/css">_x000D_
  <script src=""></script>_x000D_
    <link href="" rel="stylesheet" type="text/css" />_x000D_
 <div id="dialog" title="Wikipedia">_x000D_
   <img src="" width="320"/>_x000D_

You can also allow the users to control the size if you set resizable to true. You can see a demo about this at

Where can I find WcfTestClient.exe (part of Visual Studio)

Mine was here: "C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE"

no overload for matches delegate 'system.eventhandler'

You need to change public void klik(PaintEventArgs pea, EventArgs e) to public void klik(object sender, System.EventArgs e) because there is no Click event handler with parameters PaintEventArgs pea, EventArgs e.

How to delete the last row of data of a pandas dataframe

Just use indexing


That's why iloc exists. You can also use head or tail.

Get the records of last month in SQL server

All the existing (working) answers have one of two problems:

  1. They will ignore indices on the column being searched
  2. The will (potentially) select data that is not intended, silently corrupting your results.

1. Ignored Indices:

For the most part, when a column being searched has a function called on it (including implicitly, like for CAST), the optimizer must ignore indices on the column and search through every record. Here's a quick example:

We're dealing with timestamps, and most RDBMSs tend to store this information as an increasing value of some sort, usually a long or BIGINTEGER count of milli-/nanoseconds. The current time thus looks/is stored like this:

1402401635000000  -- 2014-06-10 12:00:35.000000 GMT

You don't see the 'Year' value ('2014') in there, do you? In fact, there's a fair bit of complicated math to translate back and forth. So if you call any of the extraction/date part functions on the searched column, the server has to perform all that math just to figure out if you can include it in the results. On small tables this isn't an issue, but as the percentage of rows selected decreases this becomes a larger and larger drain. Then in this case, you're doing it a second time for asking about MONTH... well, you get the picture.

2. Unintended data:

Depending on the particular version of SQL Server, and column datatypes, using BETWEEN (or similar inclusive upper-bound ranges: <=) can result in the wrong data being selected. Essentially, you potentially end up including data from midnight of the "next" day, or excluding some portion of the "current" day's records.

What you should be doing:

So we need a way that's safe for our data, and will use indices (if viable). The correct way is then of the form:

WHERE date_created >= @startOfPreviousMonth AND date_created < @startOfCurrentMonth

Given that there's only one month, @startOfPreviousMonth can be easily substituted for/derived by:

DATEADD(month, -1, @startOCurrentfMonth)

If you need to derive the start-of-current-month in the server, you can do it via the following:


A quick word of explanation here. The initial DATEDIFF(...) will get the difference between the start of the current era (0001-01-01 - AD, CE, whatever), essentially returning a large integer. This is the count of months to the start of the current month. We then add this number to the start of the era, which is at the start of the given month.

So your full script could/should look similar to the following:

DECLARE @startOfCurrentMonth DATETIME
SET @startOfCurrentMonth = DATEADD(month, DATEDIFF(month, 0, CURRENT_TIMESTAMP), 0)

FROM Member
WHERE date_created >= DATEADD(month, -1, @startOfCurrentMonth) -- this was originally    misspelled
      AND date_created < @startOfCurrentMonth

All date operations are thus only performed once, on one value; the optimizer is free to use indices, and no incorrect data will be included.

Converting two lists into a matrix

Simple you can try this

a=list(zip(portfolio, index))

Determining 32 vs 64 bit in C++

If you can use project configurations in all your environments, that would make defining a 64- and 32-bit symbol easy. So you'd have project configurations like this:

32-bit Debug
32-bit Release
64-bit Debug
64-bit Release

EDIT: These are generic configurations, not targetted configurations. Call them whatever you want.

If you can't do that, I like Jared's idea.

Force IE9 to emulate IE8. Possible?

On the client side you can add and remove websites to be displayed in Compatibility View from Compatibility View Settings window of IE:

Tools-> Compatibility View Settings

Enabling CORS in Cloud Functions for Firebase

Simple solution using the Google Cloud Console Dashboard:

  1. Go to your GCP console dashboard:

  1. Go to menu

"Cloud Functions" ("Compute" section)

  1. Select your cloud function, e.g. "MyFunction", a side menu should appear on the right showing you the access control settings for it

  2. Click on "Add Member", type in "allUsers" and select the role "Cloud Function Invoker"

  3. Save it -> now, you should see a remark "Allow unauthenticated" in the list of your cloud functions

Access is now available to everybody from the internet with the correct config to your GCP or Firebase project. (Be careful)

Duplicate ID, tag null, or parent id with another fragment for

I respect all the answers but i found this one liner solution: If n Is the Number of tabs then:


Example: In case mentioned :


View pager implements a queue so, you don't have to let it remove that fragment. onCreateView is called only once.

How to unpack pkl file?

The pickle (and gzip if the file is compressed) module need to be used

NOTE: These are already in the standard Python library. No need to install anything new

JavaScript displaying a float to 2 decimal places

You could do it with the toFixed function, but it's buggy in IE. If you want a reliable solution, look at my answer here.

Numpy - add row to array

If you can do the construction in a single operation, then something like the vstack-with-fancy-indexing answer is a fine approach. But if your condition is more complicated or your rows come in on the fly, you may want to grow the array. In fact the numpythonic way to do something like this - dynamically grow an array - is to dynamically grow a list:

A = np.array([[1,2,3],[4,5,6]])
Alist = [r for r in A]
for i in range(100):
    newrow = np.arange(3)+i
    if i%5:
A = np.array(Alist)
del Alist

Lists are highly optimized for this kind of access pattern; you don't have convenient numpy multidimensional indexing while in list form, but for as long as you're appending it's hard to do better than a list of row arrays.

How to allow user to pick the image with Swift?

    @IBAction func chooseProfilePicBtnClicked(sender: AnyObject) {
    let alert:UIAlertController=UIAlertController(title: "Choose Image", message: nil, preferredStyle: UIAlertControllerStyle.ActionSheet)
    let cameraAction = UIAlertAction(title: "Camera", style: UIAlertActionStyle.Default)
            UIAlertAction in
    let gallaryAction = UIAlertAction(title: "Gallary", style: UIAlertActionStyle.Default)
            UIAlertAction in
    let cancelAction = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.Cancel)
            UIAlertAction in

    // Add the actions
    picker.delegate = self
    self.presentViewController(alert, animated: true, completion: nil)
func openCamera(){
    if(UIImagePickerController .isSourceTypeAvailable(UIImagePickerControllerSourceType.Camera)){
        picker.sourceType = UIImagePickerControllerSourceType.Camera
        self .presentViewController(picker, animated: true, completion: nil)
        let alert = UIAlertView()
        alert.title = "Warning"
        alert.message = "You don't have camera"
func openGallary(){
    picker.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
    self.presentViewController(picker, animated: true, completion: nil)
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]){
    picker .dismissViewControllerAnimated(true, completion: nil)
    imageViewRef.image=info[UIImagePickerControllerOriginalImage] as? UIImage
func imagePickerControllerDidCancel(picker: UIImagePickerController){
    print("picker cancel.")

Do you have to put Task.Run in a method to make it async?

One of the most important thing to remember when decorating a method with async is that at least there is one await operator inside the method. In your example, I would translate it as shown below using TaskCompletionSource.

private Task<int> DoWorkAsync()
    //create a task completion source
    //the type of the result value must be the same
    //as the type in the returning Task
    TaskCompletionSource<int> tcs = new TaskCompletionSource<int>();
    Task.Run(() =>
        int result = 1 + 2;
        //set the result to TaskCompletionSource
    //return the Task
    return tcs.Task;

private async void DoWork()
    int result = await DoWorkAsync();

Writing a pandas DataFrame to CSV file

To delimit by a tab you can use the sep argument of to_csv:

df.to_csv(file_name, sep='\t')

To use a specific encoding (e.g. 'utf-8') use the encoding argument:

df.to_csv(file_name, sep='\t', encoding='utf-8')

Set Response Status Code

I don't think you're setting the header correctly, try this:

header('HTTP/1.0 401 Unauthorized');

Link to "pin it" on pinterest without generating a button

The standard Pinterest button code (which you can generate here), is an <a> tag wrapping an <img> of the Pinterest button.

If you don't include the pinit.js script on your page, this <a> tag will work "as-is". You could improve the experience by registering your own click handler on these tags that opens a new window with appropriate dimensions, or at least adding target="_blank" to the tag to make it open clicks in a new window.

The tag syntax would look like:

<a href="{URI-encoded URL of the page to pin}&media={URI-encoded URL of the image to pin}&description={optional URI-encoded description}" class="pin-it-button" count-layout="horizontal">
    <img border="0" src="//" title="Pin It" />

If using the JavaScript versions of sharing buttons are ruining your page load times, you can improve your site by using asynchronous loading methods. For an example of doing this with the Pinterest button, check out my GitHub Pinterest button project with an improved HTML5 syntax.

Change background color of iframe issue

JavaScript is what you need. If you are loading iframe when loading the page, insert the test for iframe using the onload event. If iframe is inserted in realtime, then create a callback function on insertion and hook in whatever action you need to take :)

How do you get the length of a list in the JSF expression language?

You mean size() don't you?


works for me (using JBoss Seam which has the Jboss EL extensions)

Retrieve a Fragment from a ViewPager

In Fragment

public int getArgument(){
   return mPage;
public void update(){


In FragmentActivity

List<Fragment> fragments = getSupportFragmentManager().getFragments();
for(Fragment f:fragments){
    if((f instanceof PageFragment)&&(!f.isDetached())){
          PageFragment pf = (PageFragment)f;   

What is code coverage and how do YOU measure it?

Code coverage has been explained well in the previous answers. So this is more of an answer to the second part of the question.

We've used three tools to determine code coverage.

  1. JTest - a proprietary tool built over JUnit. (It generates unit tests as well.)
  2. Cobertura - an open source code coverage tool that can easily be coupled with JUnit tests to generate reports.
  3. Emma - another - this one we've used for a slightly different purpose than unit testing. It has been used to generate coverage reports when the web application is accessed by end-users. This coupled with web testing tools (example: Canoo) can give you very useful coverage reports which tell you how much code is covered during typical end user usage.

We use these tools to

  • Review that developers have written good unit tests
  • Ensure that all code is traversed during black-box testing

Showing alert in angularjs when user leaves a page

The code for the confirmation dialogue can be written shorter this way:

$scope.$on('$locationChangeStart', function( event ) {
    var answer = confirm("Are you sure you want to leave this page?")
    if (!answer) {

C# switch statement limitations - why?

This is my original post, which sparked some debate... because it is wrong:

The switch statement is not the same thing as a big if-else statement. Each case must be unique and evaluated statically. The switch statement does a constant time branch regardless of how many cases you have. The if-else statement evaluates each condition until it finds one that is true.

In fact, the C# switch statement is not always a constant time branch.

In some cases the compiler will use a CIL switch statement which is indeed a constant time branch using a jump table. However, in sparse cases as pointed out by Ivan Hamilton the compiler may generate something else entirely.

This is actually quite easy to verify by writing various C# switch statements, some sparse, some dense, and looking at the resulting CIL with the ildasm.exe tool.

HTML5 Video Autoplay not working correctly

html {_x000D_
  padding: 20px 0;_x000D_
  background-color: #efefef;_x000D_
body {_x000D_
  width: 400px;_x000D_
  padding: 40px;_x000D_
  margin: 0 auto;_x000D_
  background: #fff;_x000D_
  box-shadow: 1px 1px 5px rgba(0, 0, 0, 0.5);_x000D_
video {_x000D_
  width: 400px;_x000D_
  display: block;_x000D_
<video onloadeddata=";this.muted=false;" poster="" playsinline loop muted controls>_x000D_
    <source src="" type="video/mp4" />_x000D_
    Your browser does not support the video tag or the file format of this video._x000D_

Uncaught ReferenceError: $ is not defined

I modified the script tag to point to the right content and changed the script order to be the right one in the editor. But totally forgot to save the change.

SET versus SELECT when assigning variables?

Quote, which summarizes from this article:

  1. SET is the ANSI standard for variable assignment, SELECT is not.
  2. SET can only assign one variable at a time, SELECT can make multiple assignments at once.
  3. If assigning from a query, SET can only assign a scalar value. If the query returns multiple values/rows then SET will raise an error. SELECT will assign one of the values to the variable and hide the fact that multiple values were returned (so you'd likely never know why something was going wrong elsewhere - have fun troubleshooting that one)
  4. When assigning from a query if there is no value returned then SET will assign NULL, where SELECT will not make the assignment at all (so the variable will not be changed from its previous value)
  5. As far as speed differences - there are no direct differences between SET and SELECT. However SELECT's ability to make multiple assignments in one shot does give it a slight speed advantage over SET.

momentJS date string add 5 days

You can add days in different formats:

// Normal adding
moment().add(7, 'days');

// Short Hand
moment().add(7, 'd');

// Literal Object    
moment().add({days:7, months:1});

See more about it on Moment.js docs:

How to set MimeBodyPart ContentType to "text/html"?

There is a method setText() which takes 3 arguments :

public void setText(String text, String charset, String subtype)
    throws MessagingException


text - the text content to set
charset - the charset to use for the text
subtype - the MIME subtype to use (e.g., "html")

NOTE: the subtype takes text after / in MIME types so for ex.

  • text/html would be html
  • text/css would be css
  • and so on..

How to disable phone number linking in Mobile Safari?

Add this, I think it is what you're looking for:

<meta name = "format-detection" content = "telephone=no">

Return 0 if field is null in MySQL

None of the above answers were complete for me. If your field is named field, so the selector should be the following one:

IFNULL(`field`,0) AS field

For example in a SELECT query:

SELECT IFNULL(`field`,0) AS field, `otherfield` FROM `mytable`

Hope this can help someone to not waste time.

The database cannot be opened because it is version 782. This server supports version 706 and earlier. A downgrade path is not supported

Try to change the compatibility level, worked for me.

Verify what level it is

SELECT compatibility_level
FROM sys.databases WHERE name = 'VJ_DATABASE';

Then make it compatible with the older version

  • 100 = Sql Server 2008
  • 110 = Sql Server 2012
  • 120 = Sql Server 2014

By default, Sql Server 2014 will change the db versions compatibility to only 2014, using the @@ version you should be able to tell, which version Sql Server is.

Then run the command above to change it the version you have.

Additional step: Ensure you look at the accessibility of the DB is not reset, do this by right clicking on properties of the folder and the database. (make sure you have rights so you don't get an access denied)

Send a SMS via intent

Create the Intent like this:

   Uri uriSms = Uri.parse("smsto:1234567899");   
   Intent intentSMS = new Intent(Intent.ACTION_SENDTO, uriSms);   
   intentSMS.putExtra("sms_body", "The SMS text");   

Fatal error: Call to undefined function sqlsrv_connect()

If you are using Microsoft Drivers 3.1, 3.0, and 2.0. Please check your PHP version already install with IIS.

Use this script to check the php version:

<?php echo phpinfo(); ?>


If you have installed PHP Manager in IIS using web platform Installer you can check the version from it.

If you are using new PHP version (5.6) please download Drivers from here

For PHP version Lower than 5.6 - please download Drivers from here

  • PHP Driver version 3.1 requires PHP 5.4.32, or PHP 5.5.16, or later.
  • PHP Driver version 3.0 requires PHP 5.3.0 or later. If possible, use PHP 5.3.6, or later.
  • PHP Driver version 2.0 driver works with PHP 5.2.4 or later, but not with PHP 5.4. If possible, use PHP 5.2.13, or later.

Then use the PHP Manager to add that downloaded drivers into php config file.You can do it as shown below (browse the files and press OK). Then Restart the IIS Server

enter image description here

If this method not work please change the php version and try to run your php script. enter image description here

Tip:Change the php version to lower and try to understand what happened.then you can download relevant drivers.

Pandas Merge - How to avoid duplicating columns

I'm freshly new with Pandas but I wanted to achieve the same thing, automatically avoiding column names with _x or _y and removing duplicate data. I finally did it by using this answer and this one from Stackoverflow




    30;Springfield;4;I import pandas

def drop_y(df):
    # list comprehension of the cols that end with '_y'
    to_drop = [x for x in df if x.endswith('_y')]
    df.drop(to_drop, axis=1, inplace=True)

sales = pandas.read_csv('data/sales.csv', delimiter=';')
revenue = pandas.read_csv('data/revenue.csv', delimiter=';')

result = pandas.merge(sales, revenue,  how='inner', left_on=['state'], right_on=['state_id'], suffixes=('', '_y'))
result.to_csv('results/output.csv', index=True, index_label='id', sep=';')

When executing the merge command I replace the _x suffix with an empty string and them I can remove columns ending with _y



How to work with progress indicator in flutter?

I took the following approach, which uses a simple modal progress indicator widget that wraps whatever you want to make modal during an async call.

The example in the package also addresses how to handle form validation while making async calls to validate the form (see flutter/issues/9688 for details of this problem). For example, without leaving the form, this async form validation method can be used to validate a new user name against existing names in a database while signing up.

Here is the demo of the example provided with the package (with source code):

async form validation with modal progress indicator

Example could be adapted to other modal progress indicator behaviour (like different animations, additional text in modal, etc..).

Why use the INCLUDE clause when creating an index?

One reason to prefer INCLUDE over key-columns if you don't need that column in the key is documentation. That makes evolving indexes much more easy in the future.

Considering your example:

CREATE INDEX idx1 ON MyTable (Col1) INCLUDE (Col2, Col3)

That index is best if your query looks like this:

SELECT col2, col3
  FROM MyTable
 WHERE col1 = ...

Of course you should not put columns in INCLUDE if you can get an additional benefit from having them in the key part. Both of the following queries would actually prefer the col2 column in the key of the index.

SELECT col2, col3
  FROM MyTable
 WHERE col1 = ...
   AND col2 = ...
SELECT TOP 1 col2, col3
  FROM MyTable
 WHERE col1 = ...
 ORDER BY col2

Let's assume this is not the case and we have col2 in the INCLUDE clause because there is just no benefit of having it in the tree part of the index.

Fast forward some years.

You need to tune this query:

  FROM MyTable
 WHERE col1 = ...
 ORDER BY another_col

To optimize that query, the following index would be great:

CREATE INDEX idx1 ON MyTable (Col1, another_col) INCLUDE (Col2)

If you check what indexes you have on that table already, your previous index might still be there:

CREATE INDEX idx1 ON MyTable (Col1) INCLUDE (Col2, Col3)

Now you know that Col2 and Col3 are not part of the index tree and are thus not used to narrow the read index range nor for ordering the rows. Is is rather safe to add another_column to the end of the key-part of the index (after col1). There is little risk to break anything:

DROP INDEX idx1 ON MyTable;
CREATE INDEX idx1 ON MyTable (Col1, another_col) INCLUDE (Col2, Col3);

That index will become bigger, which still has some risks, but it is generally better to extend existing indexes compared to introducing new ones.

If you would have an index without INCLUDE, you could not know what queries you would break by adding another_col right after Col1.

CREATE INDEX idx1 ON MyTable (Col1, Col2, Col3)

What happens if you add another_col between Col1 and Col2? Will other queries suffer?

There are other "benefits" of INCLUDE vs. key columns if you add those columns just to avoid fetching them from the table. However, I consider the documentation aspect the most important one.

To answer your question:

what guidelines would you suggest in determining whether to create a covering index with or without the INCLUDE clause?

If you add a column to the index for the sole purpose to have that column available in the index without visiting the table, put it into the INCLUDE clause.

If adding the column to the index key brings additional benefits (e.g. for order by or because it can narrow the read index range) add it to the key.

You can read a longer discussion about this here:

javascript, is there an isObject function like isArray?

In jQuery there is $.isPlainObject() method for that:

Description: Check to see if an object is a plain object (created using "{}" or "new Object").

How to test an Oracle Stored Procedure with RefCursor return type?

In SQL Developer you can right-click on the package body then select RUN. The 'Run PL/SQL' window will let you edit the PL/SQL Block. Clicking OK will give you a window pane titled 'Output Variables - Log' with an output variables tab. You can select your output variables on the left and the result is shown on the right side. Very handy and fast.

I've used Rapid with T-SQL and I think there was something similiar to this.

Writing your own delcare-begin-end script where you loop through the cursor, as with DCookie's example, is always a good exercise to do every now and then. It will work with anything and you will know that your code works.

SQLite with encryption/password protection

Well, SEE is expensive. However SQLite has interface built-in for encryption (Pager). This means, that on top of existing code one can easily develop some encryption mechanism, does not have to be AES. Anything really. Please see my post here:

You need to define SQLITE_HAS_CODEC=1 to enable Pager encryption. Sample code below (original SQLite source):

** This function is called by the wal module when writing page content
** into the log file.
** This function returns a pointer to a buffer containing the encrypted
** page content. If a malloc fails, this function may return NULL.
SQLITE_PRIVATE void *sqlite3PagerCodec(PgHdr *pPg){
  void *aData = 0;
  CODEC2(pPg->pPager, pPg->pData, pPg->pgno, 6, return 0, aData);
  return aData;

There is a commercial version in C language for SQLite encryption using AES256 - it can also work with PHP, but it needs to be compiled with PHP and SQLite extension. It de/encrypts SQLite database file on the fly, file contents are always encrypted. Very useful.

Cannot open Windows.h in Microsoft Visual Studio

If you already haven't done it, try adding "SDK Path\Include" to:

Project ? Preferences ? C/C++ ? General ? Additional Include Directories

And add "SDK Path\Lib" to:

Project ? Preferences ? Linker ? General ? Additional Library Directories

Also, try to change "Windows.h" to <windows.h>

If won't help, check the physical existence of the file, it should be in "\VC\PlatformSDK\Include" folder in your Visual Studio install directory.

Regular expression to match characters at beginning of line only

Not sure how to apply that to your file on your server, but typically, the regex to match the beginning of a string would be :


The ^ means beginning of string / line

Cannot find module cv2 when using OpenCV

I know you had the issue with Occidentalis, but I had the issue on Windows too, and I didn't found anything helpful. So if you have windows, and you've installed opencv, but you still get an Import error, this method will maybe solve the issue.

I managed to solve the issue, by reactivating anaconda.

First I deleted your\path\to\anaconda3 and your\path\to\anaconda3\Scripts from PATH (you will need these later, so remember these paths)

Then if you run python from cmd it will say:

This Python interpreter is in a conda environment, but the environment has
not been activated. Libraries may fail to load. To activate this environment
please see

Then in Anaconda prompt I ran these:

your\path\to\anconda3\Scripts\activate base 
conda activate --stack your\path\to\anaconda3

I'm not sure about is this the easiest way to reactivate anaconda, but this is what worked for me.

Regex - how to match everything except a particular pattern

You could use a look-ahead assertion:


This example matches three digits other than 999.

But if you happen not to have a regular expression implementation with this feature (see Comparison of Regular Expression Flavors), you probably have to build a regular expression with the basic features on your own.

A compatible regular expression with basic syntax only would be:


This does also match any three digits sequence that is not 999.

Python Tkinter clearing a frame

Returns a list of all w's children, in their stacking order from lowest (bottom) to highest (top).

for widget in frame.winfo_children():

Will destroy all the widget in your frame. No need for a second frame.

Create multiple threads and wait all of them to complete

Most proposed answers don't take into account a time-out interval, which is very important to prevent a possible deadlock. Next is my sample code. (Note that I'm primarily a Win32 developer, and that's how I'd do it there.)

//'arrRunningThreads' = List<Thread>

//Wait for all threads
const int knmsMaxWait = 3 * 1000;           //3 sec timeout
int nmsBeginTicks = Environment.TickCount;
foreach(Thread thrd in arrRunningThreads)
    //See time left
    int nmsElapsed = Environment.TickCount - nmsBeginTicks;
    int nmsRemain = knmsMaxWait - nmsElapsed;
    if(nmsRemain < 0)
        nmsRemain = 0;

    //Then wait for thread to exit
        //It didn't exit in time, terminate it

        //Issue a debugger warning
        Debug.Assert(false, "Terminated thread");

How to get image width and height in OpenCV?

Also for openCV in python you can do:

img = cv2.imread('myImage.jpg')
height, width, channels = img.shape 

Update Eclipse with Android development tools v. 23

I did this to solve the same issue (in OS X):

  1. Help > Install New Software > Add or select this repository ""
  2. Under "Eclipse platform" select the newest version of Eclipse.
  3. The installer will ask if you want to uninstall the ADT, click finish.
  4. Restart Eclipse and install ONLY the ADT 23 using this repository:
  5. Restart Eclipse and install DDMS, Hierarchy Viewer, Trace View etc.
  6. Restart Eclipse again.

Hope it helps.

How to change the font size on a matplotlib plot

Update: See the bottom of the answer for a slightly better way of doing it.
Update #2: I've figured out changing legend title fonts too.
Update #3: There is a bug in Matplotlib 2.0.0 that's causing tick labels for logarithmic axes to revert to the default font. Should be fixed in 2.0.1 but I've included the workaround in the 2nd part of the answer.

This answer is for anyone trying to change all the fonts, including for the legend, and for anyone trying to use different fonts and sizes for each thing. It does not use rc (which doesn't seem to work for me). It is rather cumbersome but I could not get to grips with any other method personally. It basically combines ryggyr's answer here with other answers on SO.

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.font_manager as font_manager

# Set the font dictionaries (for plot title and axis titles)
title_font = {'fontname':'Arial', 'size':'16', 'color':'black', 'weight':'normal',
              'verticalalignment':'bottom'} # Bottom vertical alignment for more space
axis_font = {'fontname':'Arial', 'size':'14'}

# Set the font properties (for use in legend)   
font_path = 'C:\Windows\Fonts\Arial.ttf'
font_prop = font_manager.FontProperties(fname=font_path, size=14)

ax = plt.subplot() # Defines ax variable by creating an empty plot

# Set the tick labels font
for label in (ax.get_xticklabels() + ax.get_yticklabels()):

x = np.linspace(0, 10)
y = x + np.random.normal(x) # Just simulates some data

plt.plot(x, y, 'b+', label='Data points')
plt.xlabel("x axis", **axis_font)
plt.ylabel("y axis", **axis_font)
plt.title("Misc graph", **title_font)
plt.legend(loc='lower right', prop=font_prop, numpoints=1)
plt.text(0, 0, "Misc text", **title_font)

The benefit of this method is that, by having several font dictionaries, you can choose different fonts/sizes/weights/colours for the various titles, choose the font for the tick labels, and choose the font for the legend, all independently.


I have worked out a slightly different, less cluttered approach that does away with font dictionaries, and allows any font on your system, even .otf fonts. To have separate fonts for each thing, just write more font_path and font_prop like variables.

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.font_manager as font_manager
import matplotlib.ticker
# Workaround for Matplotlib 2.0.0 log axes bug :
matplotlib.ticker._mathdefault = lambda x: '\\mathdefault{%s}'%x 

# Set the font properties (can use more variables for more fonts)
font_path = 'C:\Windows\Fonts\AGaramondPro-Regular.otf'
font_prop = font_manager.FontProperties(fname=font_path, size=14)

ax = plt.subplot() # Defines ax variable by creating an empty plot

# Define the data to be plotted
x = np.linspace(0, 10)
y = x + np.random.normal(x)
plt.plot(x, y, 'b+', label='Data points')

for label in (ax.get_xticklabels() + ax.get_yticklabels()):
    label.set_fontsize(13) # Size here overrides font_prop

plt.title("Exponentially decaying oscillations", fontproperties=font_prop,
          size=16, verticalalignment='bottom') # Size here overrides font_prop
plt.xlabel("Time", fontproperties=font_prop)
plt.ylabel("Amplitude", fontproperties=font_prop)
plt.text(0, 0, "Misc text", fontproperties=font_prop)

lgd = plt.legend(loc='lower right', prop=font_prop) # NB different 'prop' argument for legend
lgd.set_title("Legend", prop=font_prop)

Hopefully this is a comprehensive answer

Java compile error: "reached end of file while parsing }"

Yes. You were missing a '{' under the public class line. And then one at the end of your code to close it.

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

The variable left of the : is a parameter name. The use of variable on the right is making use of the parameter.

Means almost exactly the same as:

def some_method(variable):
  return variable[0]

Check if object is a jQuery object

return el instanceof jQuery ? el.size() > 0 : (el && el.tagName);

How to stop an animation (cancel() does not work)

To stop animation you may set such objectAnimator that do nothing, e.g.

first when manual flipping there is animation left to right:


then when switching to auto flipping there's no animation


doNothing = ObjectAnimator.ofFloat(flipper, "x", 0f, 0f).setDuration(flipperSwipingDuration);

What does the red exclamation point icon in Eclipse mean?

According to the documentation:

Decorates Java projects and working sets that contain build path errors

In practice, I've found that a "build path error" may be caused by any number of reasons, depending on what plugins are active. Check the "Problems" view for more information.

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

I'm assume you cannot get css working for your button using anchor tag. So you need to override the css styles which are being overwritten by other elements using !important property.


<a href="#" class="selected_btn" data-role="button">Button name</a>


    border:1px solid red;
    color:red !important;            
    background:url('') repeat-x;

Here is the demo

JavaScript string encryption and decryption?

crypt.subtle AES-GCM, self-contained, tested:

async function aesGcmEncrypt(plaintext, password)

async function aesGcmDecrypt(ciphertext, password)

Get the string value from List<String> through loop for display

Try following if your looking for while loop implementation.

List<String> myString = new ArrayList<String>();

// How you add your data in string list
myString.add("Test 1");
myString.add("Test 2");
myString.add("Test 3");
myString.add("Test 4");

int i = 0;
while (i < myString.size()) {

Error in : figure margins too large, Scatter plot

Just run before plotting your data. This instruction solved my error. So, it's harmless to try it before taking a more complex solution.

How to access site running apache server over lan without internet connection

if you did change the httpd.conf file located under conf_files folder, don't use windows notepad, you need a unix text editor, try TED pad, after making any changes to your httpd.conf file save it. ps: if you use a dos/windows editor you will end up with an "Error in Apache file changed" message. so do be careful.... Salam

Call static method with reflection

You could really, really, really optimize your code a lot by paying the price of creating the delegate only once (there's also no need to instantiate the class to call an static method). I've done something very similar, and I just cache a delegate to the "Run" method with the help of a helper class :-). It looks like this:

static class Indent{    
     public static void Run(){
         // implementation
     // other helper methods

static class MacroRunner {

    static MacroRunner() {

    static void BuildMacroRunnerList() {
        macroRunners = System.Reflection.Assembly.GetExecutingAssembly()
            .Where(x => x.Namespace.ToUpper().Contains("MACRO"))
            .Select(t => (Action)Delegate.CreateDelegate(
                t.GetMethod("Run", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.Public)))

    static List<Action> macroRunners;

    public static void Run() {
        foreach(var run in macroRunners)

It is MUCH faster this way.

If your method signature is different from Action you could replace the type-casts and typeof from Action to any of the needed Action and Func generic types, or declare your Delegate and use it. My own implementation uses Func to pretty print objects:

static class PrettyPrinter {

    static PrettyPrinter() {

    static void BuildPrettyPrinterList() {
        printers = System.Reflection.Assembly.GetExecutingAssembly()
            .Where(x => x.Name.EndsWith("PrettyPrinter"))
            .Select(t => (Func<object, string>)Delegate.CreateDelegate(
                typeof(Func<object, string>), 
                t.GetMethod("Print", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.Public)))

    static List<Func<object, string>> printers;

    public static void Print(object obj) {
        foreach(var printer in printers)

pip: no module named _internal

An answer from askUbuntu works.

For pip2.7, you can at first curl -o, then python2.7 --force-reinstall to reinstall pip.

Problem solved. Also works for python3.

npm can't find package.json

Use the command in win7/win8/win10 (CD) for moving folders:

  1. Enter your projects folder

  2. Run: npm install -d

How to combine two vectors into a data frame

This should do the trick, to produce the data frame you asked for, using only base R:

df <- data.frame(cond=c(rep("x", times=length(x)), 
                        rep("y", times=length(y))), 
                 rating=c(x, y))

  cond rating
1    x      1
2    x      2
3    x      3
4    y    100
5    y    200
6    y    300

However, from your initial description, I'd say that this is perhaps a more likely usecase:

df2 <- data.frame(x, y)
colnames(df2) <- c(x_name, y_name)

  cond rating
1    1    100
2    2    200
3    3    300

[edit: moved parentheses in example 1]

How to create an array for JSON using PHP?



    $user="select * from tbl_registration where member_id= '".$username."' ";
    $rsuser = $obj->select($user);
        //   (Status if 2 then its expire)    (1= use) ( 0 = not use)

        $cheknew="select name,ldate,offer_photo  from tbl_offer where status=1 ";
        $rscheknew = $obj->selectjson($cheknew);


            echo "{\"status\" : \"200\" ,\"responce\" : \"201\", \"message\" : \"Get Record\",\"feed\":".str_replace("<p>","",$nik). "}";
            $row2="No Record Found";
            echo "{\"status\" : \"202\",  \"responce\" : \"604\",\"message\" : \"No Record Found \",\"feed\":".str_replace("<p>","",$nik1). "}";
        $row2="Invlid User";
        echo "{\"status\" : \"404\", \"responce\" : \"602\",\"message\" : \"Invlid User \",\"feed\":".str_replace("<p>","",$nik1). "}";


How to calculate a mod b in Python?

There's the % sign. It's not just for the remainder, it is the modulo operation.

Twitter Bootstrap modal: How to remove Slide down effect

Wanted to update this. Most of you have not completed this issue. I'm using Bootstrap 3. none of the fixes above worked.

to remove the slide effect but keep the fade in. I went into bootstrap css and (noted out the following selectors) - this resolved the issue.

 .modal.fade .modal-dialog{/*-webkit-transform:translate(0,-25%);-ms-transform:translate(0,-25%);transform:translate(0,-25%);-webkit-transition:-webkit-transform .3s ease-out;-moz-transition:-moz-transform .3s ease-out;-o-transition:-o-transform .3s ease-out;transition:transform .3s ease-out*/} .modal-dialog{/*-webkit-transform:translate(0,0);-ms-transform:translate(0,0);transform:translate(0,0)*/}

Xcode : Adding a project as a build dependency

Tough one for a newbie like me - here is a screenshot that describes it.
Xcode 10.2.1

enter image description here

How to get the IP address of the docker host from inside a docker container

Try this:

docker run --rm -i --net=host alpine ifconfig

onclick="location.href='link.html'" does not load page in Safari

Give this a go:

<option onclick="parent.location='#5.2'">Bookmark 2</option>

Refused to display 'url' in a frame because it set 'X-Frame-Options' to 'SAMEORIGIN'

You cannot display a lot of websites inside an iFrame. Reason being that they send an "X-Frame-Options: SAMEORIGIN" response header. This option prevents the browser from displaying iFrames that are not hosted on the same domain as the parent page. This is a security feature to prevent click-jacking. Some details at How to show in an iframe?

This could be of some help :

Reset textbox value in javascript

this is might be a possible solution

void 0 != document.getElementById("ad") &&       (document.getElementById("ad").onclick =function(){
 var a = $("#client_id").val();
 var b = $("#contact").val();
 var c = $("#message").val();
 var Qdata = { client_id: a, contact:b, message:c }
 var respo='';

return $.ajax({

    url: applicationPath ,
    type: "POST",
    data: Qdata,
    success: function(e) {
         $("#mcg").html("msg send successfully");




How to add MVC5 to Visual Studio 2013?

Select web development tools when you install the visual studio 2013. Then it will work properly and show the web applicaton.

adb is not recognized as internal or external command on windows

You have two ways:

First go to the particular path of Android SDK:

1) Open your command prompt and traverse to the platform-tools directory through it such as

$ cd Frameworks\Android-Sdk\platform-tools

2) Run your adb commands now such as to know that your adb is working properly :

$ adb devices OR adb logcat OR simply adb

Second way is :

1) Right click on your My Computer.

2) Open Environment variables.

3) Add new variable to your System PATH variable(Add if not exist otherwise no need to add new variable if already exist).

4) Add path of platform-tools directory to as value of this variable such as C:\Program Files\android-sdk\platform-tools.

5) Restart your computer once.

6) Now run the above adb commands such adb devices or other adb commands from anywhere in command prompt.

Also on you can fire a command on terminal setx PATH "%PATH%;C:\Program Files\android-sdk\platform-tools"

What is the best way to test for an empty string in Go?

Assuming that empty spaces and all leading and trailing white spaces should be removed:

import "strings"
if len(strings.TrimSpace(s)) == 0 { ... }

Because :
len("") // is 0
len(" ") // one empty space is 1
len(" ") // two empty spaces is 2

AngularJS - Multiple ng-view in single template

Using regular ng-view module you cannot have more than one dynamic template.

However, this project enables you to do so (look for ui-router).

PHP string "contains"

PHP 8 or newer:

Use the str_contains function.

if (str_contains($str, "."))
    echo 'Found it';

    echo 'Not found.';

PHP 7 or older:

if (strpos($str, '.') !== FALSE)
    echo 'Found it';

    echo 'Not found.';

Note that you need to use the !== operator. If you use != or <> and the '.' is found at position 0, the comparison will evaluate to true because 0 is loosely equal to false.

What is the difference between the kernel space and the user space?

IN short kernel space is the portion of memory where linux kernel runs (top 1 GB virtual space in case of linux) and user space is the portion of memory where user application runs( bottom 3 GB of virtual memory in case of Linux. If you wanna know more the see the link given below :)

How to disable Hyper-V in command line?

In an elevated Command Prompt write this :

To disable:

bcdedit /set hypervisorlaunchtype off

To enable:

bcdedit /set hypervisorlaunchtype auto 

(From comments - restart to take effect)

How to get values and keys from HashMap?

To get all the values from a map:

for (Tab tab : hash.values()) {
    // do something with tab

To get all the entries from a map:

for ( Map.Entry<String, Tab> entry : hash.entrySet()) {
    String key = entry.getKey();
    Tab tab = entry.getValue();
    // do something with key and/or tab

Java 8 update:

To process all values:

hash.values().forEach(tab -> /* do something with tab */);

To process all entries:

hash.forEach((key, tab) -> /* do something with key and tab */);

WAMP shows error 'MSVCR100.dll' is missing when install

I had the same problem but none of the answer above worked. Here's what did the job for me:

  1. download msvcr110.dll, msvcr120.dll, msvcp120.dll and vcruntime140.dll from
  2. Copy them into System32
  3. Uninstall wamp
  4. Reinstall wamp

"ImportError: no module named 'requests'" after installing with pip

Opening CMD in the location of the already installed request folder and running "pip install requests" worked for me. I am using two different versions of Python.

I think this works because requests is now installed outside my virtual environment. Haven't checked but just thought I'd write this in, in case anyone else is going crazy searching on Google.

Why both no-cache and no-store should be used in HTTP response?

Originally we used no-cache many years ago and did run into some problems with stale content with certain browsers... Don't remember the specifics unfortunately.

We had since settled on JUST the use of no-store. Have never looked back or had a single issue with stale content by any browser or intermediaries since.

This space is certainly dominated by reality of implementations vs what happens to have been written in various RFCs. Many proxies in particular tend to think they do a better job of "improving performance" by replacing the policy they are supposed to be following with their own.

How can I find WPF controls by name or type?

You can use the VisualTreeHelper to find controls. Below is a method that uses the VisualTreeHelper to find a parent control of a specified type. You can use the VisualTreeHelper to find controls in other ways as well.

public static class UIHelper
   /// <summary>
   /// Finds a parent of a given item on the visual tree.
   /// </summary>
   /// <typeparam name="T">The type of the queried item.</typeparam>
   /// <param name="child">A direct or indirect child of the queried item.</param>
   /// <returns>The first parent item that matches the submitted type parameter. 
   /// If not matching item can be found, a null reference is being returned.</returns>
   public static T FindVisualParent<T>(DependencyObject child)
     where T : DependencyObject
      // get parent item
      DependencyObject parentObject = VisualTreeHelper.GetParent(child);

      // we’ve reached the end of the tree
      if (parentObject == null) return null;

      // check if the parent matches the type we’re looking for
      T parent = parentObject as T;
      if (parent != null)
         return parent;
         // use recursion to proceed with next level
         return FindVisualParent<T>(parentObject);

Call it like this:

Window owner = UIHelper.FindVisualParent<Window>(myControl);

Unique Key constraints for multiple columns in Entity Framework

I assume you always want EntityId to be the primary key, so replacing it by a composite key is not an option (if only because composite keys are far more complicated to work with and because it is not very sensible to have primary keys that also have meaning in the business logic).

The least you should do is create a unique key on both fields in the database and specifically check for unique key violation exceptions when saving changes.

Additionally you could (should) check for unique values before saving changes. The best way to do that is by an Any() query, because it minimizes the amount of transferred data:

if (context.Entities.Any(e => e.FirstColumn == value1 
                           && e.SecondColumn == value2))
    // deal with duplicate values here.

Beware that this check alone is never enough. There is always some latency between the check and the actual commit, so you'll always need the unique constraint + exception handling.

Outline effect to text

There is an experimental webkit property called text-stroke in CSS3, I've been trying to get this to work for some time but have been unsuccessful so far.

What I have done instead is used the already supported text-shadow property (supported in Chrome, Firefox, Opera, and IE 9 I believe).

Use four shadows to simulate a stroked text:

.strokeme {_x000D_
  color: white;_x000D_
  text-shadow: -1px -1px 0 #000, 1px -1px 0 #000, -1px 1px 0 #000, 1px 1px 0 #000;_x000D_
<div class="strokeme">_x000D_
  This text should have a stroke in some browsers_x000D_

I have made a demo for you here

And a hovered example is available here

As Jason C has mentioned in the comments, the text-shadow CSS property is now supported by all major browsers, with the exception of Opera Mini. Where this solution will work for backwards compatibility (not really an issue regarding browsers that auto-update) I believe the text-stroke CSS should be used.

php pdo: get the columns name of a table

This is an old question but here's my input

function getColumns($dbhandle, $tableName) {
    $columnsquery = $dbhandle->query("PRAGMA table_info($tableName)");
    $columns = array();
    foreach ($columnsquery as $k) {
        $columns[] = $k['name'];
    return $columns;

just put your variable for your pdo object and the tablename. Works for me

Using .text() to retrieve only text not nested in child tags

just put it in a <p> or <font> and grab that $('#listItem font').text()

First thing that came to mind

<li id="listItem">
    <font>This is some text</font>
    <span id="firstSpan">First span text</span>
    <span id="secondSpan">Second span text</span>

Remove a git commit which has not been pushed

I just had the same problem and ended up doing:

git rebase -i HEAD~N

(N is the number of commits git will show you)

That prompts your text editor and then you can remove the commit you want by deleting the line associated with it.

Best way to stress test a website

My suggestion is for you to do some automated tests first. Use selenium for it.

Then deploy selenium grid to test in multiple computers at the same time.

Although Selenium as an automated test tool will run quite fast, making a mini stress test. If you put the same automation running on a couple of computers on your network at the same time you'll be able to see how it behaves.

If you want to record response timings, they have a cool api you can use to write some scripts to run your automations.

Edit: Selenium is quite easy to use, and it does asserts to page contents if you want to test the contents. It also copies your movement through the page if you wish (this would be my suggestion) just navigate the page a lot, and then save it for automation. Avoid putting asserts so selenium might run faster.

How do I delete a local repository in git?

Delete the .git directory in the root-directory of your repository if you only want to delete the git-related information (branches, versions).

If you want to delete everything (git-data, code, etc), just delete the whole directory.

.git directories are hidden by default, so you'll need to be able to view hidden files to delete it.

Javascript: open new page in same window

The second parameter of is a string representing the name of the target window.

Set it to: "_self".

<a href="javascript:q=(document.location.href);void(open(''+escape(q),'_self','resizable,location,menubar,toolbar,scrollbars,status'));">click here</a>

Sidenote: The following question gives an overview of an arguably better way to bind event handlers to HTML links.

What's the best way to replace links with js functions?

How to get the full path of the file from a file input

You cannot do so - the browser will not allow this because of security concerns. Although there are workarounds, the fact is that you shouldn't count on this working. The following Stack Overflow questions are relevant here:

In addition to these, the new HTML5 specification states that browsers will need to feed a Windows compatible fakepath into the input type="file" field, ostensibly for backward compatibility reasons.

So trying to obtain the path is worse then useless in newer browsers - you'll actually get a fake one instead.

How to see indexes for a database or table in MySQL?

To check all disabled indexes on db

FROM information_schema.statistics
WHERE table_schema = 'mydb'
AND COMMENT = 'disabled'

When using SASS how can I import a file from a different directory?

You could use the -I command line switch or :load_paths option from Ruby code to add sub_directory_a to Sass's load path. So if you're running Sass from root_directory, do something like this:

sass -I sub_directory_a --watch sub_directory_b:sub_directory_b

Then you can simply use @import "common" in more_styles.scss.

What's the difference between emulation and simulation?

Here's an example - we recently developed a simulation model to measure the remote transmission response time of a yet-to-be-developed system. An emulation analysis would not have given us the answer in time to upgrade the bandwidth capacity so simulation was our approach. Because we were mostly interested in determining bandwidth needs, we cared primarily about transaction size and volume, not the processing of the system. The simulation model was on a stand-alone piece of software that was designed to model discrete-event processes. To summarize in response to your question, emulation is a type of simulation. But, in this case, simulation was NOT an emulation because it didn't fully represent the new system, only the size and volume of transactions.

How can I increment a char?

In Python 2.x, just use the ord and chr functions:

>>> ord('c')
>>> ord('c') + 1
>>> chr(ord('c') + 1)

Python 3.x makes this more organized and interesting, due to its clear distinction between bytes and unicode. By default, a "string" is unicode, so the above works (ord receives Unicode chars and chr produces them).

But if you're interested in bytes (such as for processing some binary data stream), things are even simpler:

>>> bstr = bytes('abc', 'utf-8')
>>> bstr
>>> bstr[0]
>>> bytes([97, 98, 99])
>>> bytes([bstr[0] + 1, 98, 99])

How to use cookies in Python Requests

You can use a session object. It stores the cookies so you can make requests, and it handles the cookies for you

s = requests.Session() 
# all cookies received will be stored in the session object'http://www...',data=payload)


You can also save the cookie data to an external file, and then reload them to keep session persistent without having to login every time you run the script:

How to save requests (python) cookies to a file?

Create Table from JSON Data with angularjs and ng-repeat

To render any json in tabular format:

        <th ng-repeat="(key, value) in vm.records[0]">{{key}}</th>
      <tr ng-repeat="(key, value) in vm.records">
        <td ng-repeat="(key, value) in value">

See complete code in detail with other features

Why should I use core.autocrlf=true in Git?

Update 2:

Xcode 9 appears to have a "feature" where it will ignore the file's current line endings, and instead just use your default line-ending setting when inserting lines into a file, resulting in files with mixed line endings.

I'm pretty sure this bug didn't exist in Xcode 7; not sure about Xcode 8. The good news is that it appears to be fixed in Xcode 10.

For the time it existed, this bug caused a small amount of hilarity in the codebase I refer to in the question (which to this day uses autocrlf=false), and led to many "EOL" commit messages and eventually to my writing a git pre-commit hook to check for/prevent introducing mixed line endings.


Note: As noted by VonC, starting from Git 2.8, merge markers will not introduce Unix-style line-endings to a Windows-style file.


One little hiccup that I've noticed with this setup is that when there are merge conflicts, the lines git adds to mark up the differences do not have Windows line-endings, even when the rest of the file does, and you can end up with a file with mixed line endings, e.g.:

// Some code<CR><LF>
<<<<<<< Updated upstream<LF>
// Change A<CR><LF>
// Change B<CR><LF>
>>>>>>> Stashed changes<LF>
// More code<CR><LF>

This doesn't cause us any problems (I imagine any tool that can handle both types of line-endings will also deal sensible with mixed line-endings--certainly all the ones we use do), but it's something to be aware of.

The other thing* we've found, is that when using git diff to view changes to a file that has Windows line-endings, lines that have been added display their carriage returns, thus:

    // Not changed

+   // New line added in^M
    // Not changed
    // Not changed

* It doesn't really merit the term: "issue".

Problems when trying to load a package in R due to rJava

Its because either one of the Java versions(32 bit/64 bit) is missing from your computer. Try installing both the Jdks and run the code.
After installing the Jdks open R and type the code

system("java -version")

This will give you the version of Jdk installed. Then try loading the rJava package. This worked for me.

What does OpenCV's cvWaitKey( ) function do?

The cvWaitKey simply provides something of a delay. For example:

char c = cvWaitKey(33);
if( c == 27 ) break;

Tis was apart of my code in which a video was loaded into openCV and the frames outputted. The 33 number in the code means that after 33ms, a new frame would be shown. Hence, the was a dely or time interval of 33ms between each frame being shown on the screen. Hope this helps.

Match at every second occurrence

If you're using C#, you can either get all the matches at once (i.e. use Regex.Matches(), which returns a MatchCollection, and check the index of the item: index % 2 != 0).

If you want to find the occurrence to replace it, use one of the overloads of Regex.Replace() that uses a MatchEvaluator (e.g. Regex.Replace(String, String, MatchEvaluator). Here's the code:

using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
    class Program
        static void Main(string[] args)
            string input = "abcdabcd";

            // Replace *second* a with m

            string replacedString = Regex.Replace(
                new SecondOccuranceFinder("m").MatchEvaluator);



        class SecondOccuranceFinder
            public SecondOccuranceFinder(string replaceWith)
                _replaceWith = replaceWith;
                _matchEvaluator = new MatchEvaluator(IsSecondOccurance);

            private string _replaceWith;

            private MatchEvaluator _matchEvaluator;
            public MatchEvaluator MatchEvaluator
                    return _matchEvaluator;

            private int _matchIndex;
            public string IsSecondOccurance(Match m)
                if (_matchIndex % 2 == 0)
                    return _replaceWith;
                    return m.Value;

TextView bold via xml file?

just use


Generating a Random Number between 1 and 10 Java

This will work for generating a number 1 - 10. Make sure you import Random at the top of your code.

import java.util.Random;

If you want to test it out try something like this.

Random rn = new Random();

for(int i =0; i < 100; i++)
    int answer = rn.nextInt(10) + 1;

Also if you change the number in parenthesis it will create a random number from 0 to that number -1 (unless you add one of course like you have then it will be from 1 to the number you've entered).

How to run a script file remotely using SSH

If you want to execute a local script remotely without saving that script remotely you can do it like this:

cat | ssh user@remotehost 'bash -'

It works like a charm for me.

I do that even from Windows to Linux given that you have MSYS installed on your Windows computer.

How do I start a program with arguments when debugging?

for .NET Core console apps you can do this 2 ways - from the launchsettings.json or the properties menu.


enter image description here

or right click the project > properties > debug tab on left

see "Application Arguments:"

  • this is " " (space) delimited, no need for any commas. just start typing. each space " " will represent a new input parameter.
  • (whatever changes you make here will be reflected in the launchsettings.json file...)

enter image description here

ASP.NET MVC View Engine Comparison

I think this list should also include samples of each view engine so users can get a flavour of each without having to visit every website.

Pictures say a thousand words and markup samples are like screenshots for view engines :) So here's one from my favourite Spark View Engine

<viewdata products="IEnumerable[[Product]]"/>
<ul if="products.Any()">
  <li each="var p in products">${p.Name}</li>
  <p>No products available</p>

How can I search Git branches for a file or directory?

git log + git branch will find it for you:

% git log --all -- somefile

commit 55d2069a092e07c56a6b4d321509ba7620664c63
Author: Dustin Sallings <[email protected]>
Date:   Tue Dec 16 14:16:22 2008 -0800

    added somefile

% git branch -a --contains 55d2069

Supports globbing, too:

% git log --all -- '**/my_file.png'

The single quotes are necessary (at least if using the Bash shell) so the shell passes the glob pattern to git unchanged, instead of expanding it (just like with Unix find).

window.print() not working in IE

<!DOCTYPE html>
<head id="head">
<meta http-equiv="X-UA-Compatible" content="IE=9; IE=8; IE=7; IE=EDGE" /> 
  <!-- saved from url=(0023) -->
  <link rel="stylesheet" type="text/css" href="style.css" />
    Do not print
  <div id="printable" style="background-color: pink">
    Print this div
  <button onClick="printdiv();">Print Div</button>
  function printdiv()
  var printContents = document.getElementById("printable").innerHTML;
  var head = document.getElementById("head").innerHTML;
  //var popupWin ='', '_blank');
  var popupWin ='print.html', 'blank');;
  popupWin.document.write(''+ '<html>'+'<head>'+head+'</head>'+'<body onload="window.print()">' + '<div id="printable">' + printContents + '</div>'+'</body>'+'</html>');
 return false;

Creating SVG elements dynamically with javascript inside HTML

To facilitate svg editing you can use an intermediate function:

function getNode(n, v) {
  n = document.createElementNS("", n);
  for (var p in v)
    n.setAttributeNS(null, p, v[p]);
  return n

Now you can write:

svg.appendChild( getNode('rect', { width:200, height:20, fill:'#ff0000' }) );

Example (with an improved getNode function allowing camelcase for property with dash, eg strokeWidth > stroke-width):

function getNode(n, v) {_x000D_
  n = document.createElementNS("", n);_x000D_
  for (var p in v)_x000D_
    n.setAttributeNS(null, p.replace(/[A-Z]/g, function(m, p, o, s) { return "-" + m.toLowerCase(); }), v[p]);_x000D_
  return n_x000D_
var svg = getNode("svg");_x000D_
var r = getNode('rect', { x: 10, y: 10, width: 100, height: 20, fill:'#ff00ff' });_x000D_
var r = getNode('rect', { x: 20, y: 40, width: 100, height: 40, rx: 8, ry: 8, fill: 'pink', stroke:'purple', strokeWidth:7 });_x000D_

'sudo gem install' or 'gem install' and gem locations

sudo gem install --no-user-install <gem-name>

will install your gem globally, i.e. it will be available to all user's contexts.

How to have a a razor action link open in a new tab?



<a href="@Url.Action("Action", "Controller")" target="_blank">Link Text</a>

How can I find the number of years between two dates?

Try this:

int getYear(Date date1,Date date2){ 
      SimpleDateFormat simpleDateformat=new SimpleDateFormat("yyyy");

      return Integer.parseInt(simpleDateformat.format(date2))- Integer.parseInt(simpleDateformat.format(date1));


caching JavaScript files

I have a simple system that is pure JavaScript. It checks for changes in a simple text file that is never cached. When you upload a new version this file is changed. Just put the following JS at the top of the page.

        (function(url, storageName) {_x000D_
            var fromStorage = localStorage.getItem(storageName);_x000D_
            var fullUrl = url + "?rand=" + (Math.floor(Math.random() * 100000000));_x000D_
            getUrl(function(fromUrl) {_x000D_
//                   first load_x000D_
                if (!fromStorage) {_x000D_
                    localStorage.setItem(storageName, fromUrl);_x000D_
//                    old file_x000D_
                if (fromStorage === fromUrl) {_x000D_
                // files updated_x000D_
                localStorage.setItem(storageName, fromUrl);_x000D_
            function getUrl(fn) {_x000D_
                var xmlhttp = new XMLHttpRequest();_x000D_
      "GET", fullUrl, true);_x000D_
                xmlhttp.onreadystatechange = function() {_x000D_
                    if (xmlhttp.readyState === XMLHttpRequest.DONE) {_x000D_
                        if (xmlhttp.status === 200 || xmlhttp.status === 2) {_x000D_
                        else if (xmlhttp.status === 400) {_x000D_
                            throw 'unable to load file for cache check ' +  url;_x000D_
                        else {_x000D_
                           throw 'unable to load file for cache check ' +  url;_x000D_
        })("version.txt", "version");

just replace the "version.txt" with your file that is always run and "version" with the name you want to use for your local storage.

How can I remove the first line of a text file using bash/sed script?

You can use -i to update the file without using '>' operator. The following command will delete the first line from the file and save it to the file.

sed -i '1d' filename

What's the yield keyword in JavaScript?

Fibonacci sequence generator using the yield keyword.

function* fibbonaci(){
    var a = -1, b = 1, c;
        c = a + b;
        a = b;
        b = c;
        yield c;

var fibonacciGenerator = fibbonaci();; // 0; // 1; // 1; // 2 

How do I check if a Key is pressed on C++

There is no portable function that allows to check if a key is hit and continue if not. This is always system dependent.

Solution for linux and other posix compliant systems:

Here, for Morgan Mattews's code provide kbhit() functionality in a way compatible with any POSIX compliant system. He uses the trick of desactivating buffering at termios level.

Solution for windows:

For windows, Microsoft offers _kbhit()

Convert Python dict into a dataframe

Accepts a dict as argument and returns a dataframe with the keys of the dict as index and values as a column.

def dict_to_df(d):
    df.set_index(0, inplace=True)
    return df

Issue with background color and Google Chrome

It must be a WebKit issue as it is in both Safari 4 and Chrome.

Why is the apt-get function not working in the terminal on Mac OS X v10.9 (Mavericks)?

Conda can also be used as package manager. It can be installed from Anaconda.

Alternatively, a free minimal installer is Miniconda.

Regex match everything after question mark?

Check out this site: Basically the site allows you to enter some example text (what you would be looking for on your site) and then as you build the regular expression it will highlight what is being matched in real time.

How to subtract X days from a date using Java calendar?

Taken from the docs here:

Adds or subtracts the specified amount of time to the given calendar field, based on the calendar's rules. For example, to subtract 5 days from the current time of the calendar, you can achieve it by calling:

Calendar calendar = Calendar.getInstance(); // this would default to now
calendar.add(Calendar.DAY_OF_MONTH, -5).

Get current value when change select option - Angular2

There is a way to get the value from different options. check this plunker


<select class="form-control" #t (change)="callType(t.value)">
  <option *ngFor="#type of types" [value]="type">{{type}}</option>


this.types = [ 'type1', 'type2', 'type3' ];

callType(value) {
  this.order.type = value;

How to get row data by clicking a button in a row in an ASP.NET gridview

     <asp:Button ID="Button1" runat="server" Text="Button" 
            OnClick="MyButtonClick" />

and your method

 protected void MyButtonClick(object sender, System.EventArgs e)
     //Get the button that raised the event
Button btn = (Button)sender;

    //Get the row that contains this button
GridViewRow gvr = (GridViewRow)btn.NamingContainer;

When to use a linked list over an array/array list?

Hmm, Arraylist can be used in cases like follows I guess:

  1. you are not sure how many elements will be present
  2. but you need to access all the elements randomly through indexing

For eg, you need to import and access all elements in a contact list (the size of which is unknown to you)

No @XmlRootElement generated by JAXB

Joe's answer (Joe Jun 26 '09 at 17:26) does it for me. The simple answer is that absence of an @XmlRootElement annotation is no problem if you marshal a JAXBElement. The thing that confused me is the generated ObjectFactory has 2 createMyRootElement methods - the first takes no parameters and gives the unwrapped object, the second takes the unwrapped object and returns it wrapped in a JAXBElement, and marshalling that JAXBElement works fine. Here's the basic code I used (I'm new to this, so apologies if the code's not formatted correctly in this reply), largely cribbed from link text:

ObjectFactory objFactory = new ObjectFactory();
MyRootElement root = objFactory.createMyRootElement();
// Set root properties
if (!writeDocument(objFactory.createMyRootElement(root), output)) {
    System.err.println("Failed to marshal XML document");

private boolean writeDocument(JAXBElement document, OutputStream output) {

  Class<?> clazz = document.getValue().getClass();
  try {
    JAXBContext context =
    Marshaller m = context.createMarshaller();
    m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
    m.marshal(document, output);
    return true;

  } catch (JAXBException e) {
    return false;

how to merge 200 csv files in Python

Let's say you have 2 csv files like these:





and you want the result to be like this csv3.csv:


Then you can use the following snippet to do that:

import csv
import pandas as pd

# the file names
f1 = "csv1.csv"
f2 = "csv2.csv"
out_f = "csv3.csv"

# read the files
df1 = pd.read_csv(f1)
df2 = pd.read_csv(f2)

# get the keys
keys1 = list(df1)
keys2 = list(df2)

# merge both files
for idx, row in df2.iterrows():
    data = df1[df1['id'] == row['id']]

    # if row with such id does not exist, add the whole row
    if data.empty:
        next_idx = len(df1)
        for key in keys2:
  [next_idx, key] =[idx, key]

    # if row with such id exists, add only the missing keys with their values
        i = int(data.index[0])
        for key in keys2:
            if key not in keys1:
      [i, key] =[idx, key]

# save the merged files
df1.to_csv(out_f, index=False, encoding='utf-8', quotechar="", quoting=csv.QUOTE_NONE)

With the help of a loop you can achieve the same result for multiple files as it is in your case (200 csv files).

how to use html2canvas and jspdf to export to pdf in a proper and simple way

I have made a jsfiddle for you.

 <canvas id="canvas" width="480" height="320"></canvas> 
      <button id="download">Download Pdf</button>


        html2canvas($("#canvas"), {
            onrendered: function(canvas) {         
                var imgData = canvas.toDataURL(
                var doc = new jsPDF('p', 'mm');
                doc.addImage(imgData, 'PNG', 10, 10);


Tested in Chrome38, IE11 and Firefox 33. Seems to have issues with Safari. However, Andrew got it working in Safari 8 on Mac OSx by switching to JPEG from PNG. For details, see his comment below.

jQuery access input hidden value

You can access hidden fields' values with val(), just like you can do on any other input element:

<input type="hidden" id="foo" name="zyx" value="bar" />


Those all mean the same thing in this example.

Find all stored procedures that reference a specific column in some table

One option is to create a script file.

Right click on the database -> Tasks -> Generate Scripts

Then you can select all the stored procedures and generate the script with all the sps. So you can find the reference from there.


-- Search in All Objects
FROM sys.sql_modules
WHERE definition LIKE '%' + 'CreatedDate' + '%'

-- Search in Stored Procedure Only
FROM sys.Procedures
WHERE object_definition(OBJECT_ID) LIKE '%' + 'CreatedDate' + '%'

Source SQL SERVER – Find Column Used in Stored Procedure – Search Stored Procedure for Column Name

Calling a Fragment method from a parent Activity

FragmentManager fm = getFragmentManager(); 
MainFragment frag = (MainFragment)fm.findFragmentById(; 

How to use ArrayList.addAll()?

Collections.addAll is what you want.

Collections.addAll(myArrayList, '+', '-', '*', '^');

Another option is to pass the list into the constructor using Arrays.asList like this:

List<Character> myArrayList = new ArrayList<Character>(Arrays.asList('+', '-', '*', '^'));

If, however, you are good with the arrayList being fixed-length, you can go with the creation as simple as list = Arrays.asList(...). Arrays.asList specification states that it returns a fixed-length list which acts as a bridge to the passed array, which could be not what you need.

What is the purpose of using WHERE 1=1 in SQL statements?

It's also a common practice when people are building the sql query programmatically, it's just easier to start with 'where 1=1 ' and then appending ' and' depending if a customer id is provided. So you can always append the next part of the query starting with 'and ...'.