Programs & Examples On #Syntax error

A syntax error occurs when a program does not follow the syntactical rules of the programming language.

Why does Eclipse complain about @Override on interface methods?

You can also try Retroweaver to create the Java5 version from Java6 classes.

Python print statement “Syntax Error: invalid syntax”

Use print("use this bracket -sample text")

In Python 3 print "Hello world" gives invalid syntax error.

To display string content in Python3 have to use this ("Hello world") brackets.

Checking whether the pip is installed?

$ which pip


 $ pip -V 

execute this command into your terminal. It should display the location of executable file eg. /usr/local/bin/pip and the second command will display the version if the pip is installed correctly.

syntax error, unexpected T_VARIABLE

There is no semicolon at the end of that instruction causing the error.


Like RiverC pointed out, there is no semicolon at the end of the previous line!

require ("scripts/connect.php") 


It seems you have no-semicolons whatsoever.

As in C or Perl, PHP requires instructions to be terminated with a semicolon at the end of each statement.

PHP Notice: Undefined offset: 1 with array when reading data

Hide php warnings in file


Syntax error: Illegal return statement in JavaScript

In my experience, most often this error message means that you have put an accidental closing brace somewhere, leaving the rest of your statements outside the function.


function a() {
    if (global_block) //syntax error is actually here - missing opening brace
    } //this unintentionally ends the function

    if (global_somethingelse) {
       //Chrome will show the error occurring here, 
       //but actually the error is in the previous statement

    //do something

What is unexpected T_VARIABLE in PHP?

It could be some other line as well. PHP is not always that exact.

Probably you are just missing a semicolon on previous line.

How to reproduce this error, put this in a file called a.php:

  $a = 5
  $b = 7;        // Error happens here.
  print $b;

Run it:

eric@dev ~ $ php a.php

PHP Parse error:  syntax error, unexpected T_VARIABLE in
/home/el/code/a.php on line 3


The PHP parser converts your program to a series of tokens. A T_VARIABLE is a Token of type VARIABLE. When the parser processes tokens, it tries to make sense of them, and throws errors if it receives a variable where none is allowed.

In the simple case above with variable $b, the parser tried to process this:

$a = 5 $b = 7;

The PHP parser looks at the $b after the 5 and says "that is unexpected".

unexpected T_VARIABLE, expecting T_FUNCTION

check that you entered a variable as argument with the '$' symbol

json Uncaught SyntaxError: Unexpected token :

That hex might need to be wrapped in quotes and made into a string. Javascript might not like the # character

How to use Switch in SQL Server

This is a select statement, so each branch of the case must return something. If you want to perform actions, just use an if.

Calling a Sub in VBA

Try -

Call CatSubProduktAreakum(Stattyp, Daty + UBound(SubCategories) + 2)

As for the reason, this from MSDN via this question - What does the Call keyword do in VB6?

You are not required to use the Call keyword when calling a procedure. However, if you use the Call keyword to call a procedure that requires arguments, argumentlist must be enclosed in parentheses. If you omit the Call keyword, you also must omit the parentheses around argumentlist. If you use either Call syntax to call any intrinsic or user-defined function, the function's return value is discarded.

No visible cause for "Unexpected token ILLEGAL"

If you are running a nginx + uwsgi setup vagrant then the main problem is the Virtual box bug with send file as mentioned in some of the answers. However to resolve it you have to disable sendfile in both nginx and uwsgi.

  1. In nginx.conf sendfile off

  2. uwsgi application / config --disable-sendfile

SyntaxError: multiple statements found while compiling a single statement

In the shell, you can't execute more than one statement at a time:

>>> x = 5
y = 6
SyntaxError: multiple statements found while compiling a single statement

You need to execute them one by one:

>>> x = 5
>>> y = 6

When you see multiple statements are being declared, that means you're seeing a script, which will be executed later. But in the interactive interpreter, you can't do more than one statement at a time.

JavaScript: SyntaxError: missing ) after argument list

You got an extra } to many as seen below:

var nav = document.getElementsByClassName('nav-coll');
for (var i = 0; i < button.length; i++) {
        } // <-- REMOVE THIS :)
    }, false);

A very good tool for those things is jsFiddle. I have created a fiddle with your invalid code and when clicking the TidyUp button it formats your code which makes it clearer if there are any possible mistakes with missing braces.

DEMO - Your code in a fiddle, have a play :)

Uncaught SyntaxError: Unexpected token u in JSON at position 0


That'll clear the stored data. Then refresh and things should start to work.

How to solve SyntaxError on autogenerated

activate env by the Following Command

  source  pathetoYourEnv/bin/activate

then run command

python runserver

How can I fix MySQL error #1064?


Error #1064 means that MySQL can't understand your command. To fix it:

  • Read the error message. It tells you exactly where in your command MySQL got confused.

  • Examine your command. If you use a programming language to create your command, use echo, console.log(), or its equivalent to show the entire command so you can see it.

  • Check the manual. By comparing against what MySQL expected at that point, the problem is often obvious.

  • Check for reserved words. If the error occurred on an object identifier, check that it isn't a reserved word (and, if it is, ensure that it's properly quoted).

  1. Aaaagh!! What does #1064 mean?

    Error messages may look like gobbledygook, but they're (often) incredibly informative and provide sufficient detail to pinpoint what went wrong. By understanding exactly what MySQL is telling you, you can arm yourself to fix any problem of this sort in the future.

    As in many programs, MySQL errors are coded according to the type of problem that occurred. Error #1064 is a syntax error.

    • What is this "syntax" of which you speak? Is it witchcraft?

      Whilst "syntax" is a word that many programmers only encounter in the context of computers, it is in fact borrowed from wider linguistics. It refers to sentence structure: i.e. the rules of grammar; or, in other words, the rules that define what constitutes a valid sentence within the language.

      For example, the following English sentence contains a syntax error (because the indefinite article "a" must always precede a noun):

      This sentence contains syntax error a.

    • What does that have to do with MySQL?

      Whenever one issues a command to a computer, one of the very first things that it must do is "parse" that command in order to make sense of it. A "syntax error" means that the parser is unable to understand what is being asked because it does not constitute a valid command within the language: in other words, the command violates the grammar of the programming language.

      It's important to note that the computer must understand the command before it can do anything with it. Because there is a syntax error, MySQL has no idea what one is after and therefore gives up before it even looks at the database and therefore the schema or table contents are not relevant.

  2. How do I fix it?

    Obviously, one needs to determine how it is that the command violates MySQL's grammar. This may sound pretty impenetrable, but MySQL is trying really hard to help us here. All we need to do is…

    • Read the message!

      MySQL not only tells us exactly where the parser encountered the syntax error, but also makes a suggestion for fixing it. For example, consider the following SQL command:

      UPDATE my_table WHERE id=101 SET name='foo'

      That command yields the following error message:

      ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE id=101 SET name='foo'' at line 1

      MySQL is telling us that everything seemed fine up to the word WHERE, but then a problem was encountered. In other words, it wasn't expecting to encounter WHERE at that point.

      Messages that say ...near '' at line... simply mean that the end of command was encountered unexpectedly: that is, something else should appear before the command ends.

    • Examine the actual text of your command!

      Programmers often create SQL commands using a programming language. For example a php program might have a (wrong) line like this:

      $result = $mysqli->query("UPDATE " . $tablename ."SET name='foo' WHERE id=101");

      If you write this this in two lines

      $query = "UPDATE " . $tablename ."SET name='foo' WHERE id=101"
      $result = $mysqli->query($query);

      then you can add echo $query; or var_dump($query) to see that the query actually says

      UPDATE userSET name='foo' WHERE id=101

      Often you'll see your error immediately and be able to fix it.

    • Obey orders!

      MySQL is also recommending that we "check the manual that corresponds to our MySQL version for the right syntax to use". Let's do that.

      I'm using MySQL v5.6, so I'll turn to that version's manual entry for an UPDATE command. The very first thing on the page is the command's grammar (this is true for every command):

      UPDATE [LOW_PRIORITY] [IGNORE] table_reference
          SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
          [WHERE where_condition]
          [ORDER BY ...]
          [LIMIT row_count]

      The manual explains how to interpret this syntax under Typographical and Syntax Conventions, but for our purposes it's enough to recognise that: clauses contained within square brackets [ and ] are optional; vertical bars | indicate alternatives; and ellipses ... denote either an omission for brevity, or that the preceding clause may be repeated.

      We already know that the parser believed everything in our command was okay prior to the WHERE keyword, or in other words up to and including the table reference. Looking at the grammar, we see that table_reference must be followed by the SET keyword: whereas in our command it was actually followed by the WHERE keyword. This explains why the parser reports that a problem was encountered at that point.

    A note of reservation

    Of course, this was a simple example. However, by following the two steps outlined above (i.e. observing exactly where in the command the parser found the grammar to be violated and comparing against the manual's description of what was expected at that point), virtually every syntax error can be readily identified.

    I say "virtually all", because there's a small class of problems that aren't quite so easy to spot—and that is where the parser believes that the language element encountered means one thing whereas you intend it to mean another. Take the following example:

    UPDATE my_table SET where='foo'

    Again, the parser does not expect to encounter WHERE at this point and so will raise a similar syntax error—but you hadn't intended for that where to be an SQL keyword: you had intended for it to identify a column for updating! However, as documented under Schema Object Names:

    If an identifier contains special characters or is a reserved word, you must quote it whenever you refer to it. (Exception: A reserved word that follows a period in a qualified name must be an identifier, so it need not be quoted.) Reserved words are listed at Section 9.3, “Keywords and Reserved Words”.

    [ deletia ]

    The identifier quote character is the backtick (“`”):

    mysql> SELECT * FROM `select` WHERE `select`.id > 100;

    If the ANSI_QUOTES SQL mode is enabled, it is also permissible to quote identifiers within double quotation marks:

    mysql> CREATE TABLE "test" (col INT);
    ERROR 1064: You have an error in your SQL syntax...
    mysql> SET sql_mode='ANSI_QUOTES';
    mysql> CREATE TABLE "test" (col INT);
    Query OK, 0 rows affected (0.00 sec)

How to correct TypeError: Unicode-objects must be encoded before hashing?

It is probably looking for a character encoding from wordlistfile.

wordlistfile = open(wordlist,"r",encoding='utf-8')

Or, if you're working on a line-by-line basis:



Per the comment below and this answer.

My answer above assumes that the desired output is a str from the wordlist file. If you are comfortable in working in bytes, then you're better off using open(wordlist, "rb"). But it is important to remember that your hashfile should NOT use rb if you are comparing it to the output of hexdigest. hashlib.md5(value).hashdigest() outputs a str and that cannot be directly compared with a bytes object: 'abc' != b'abc'. (There's a lot more to this topic, but I don't have the time ATM).

It should also be noted that this line:

line.replace("\n", "")

Should probably be


That will work for both bytes and str's. But if you decide to simply convert to bytes, then you can change the line to:

line.replace(b"\n", b"")

Ternary operators in JavaScript without an "else"

You could write

x = condition ? true : x;

So that x is unmodified when the condition is false.

This then is equivalent to

if (condition) x = true


      ? defaults.slideshowWidth = obj.find('img').width()+'px' 
      : null 

There are a couple of alternatives - I'm not saying these are better/worse - merely alternatives

Passing in null as the third parameter works because the existing value is null. If you refactor and change the condition, then there is a danger that this is no longer true. Passing in the exising value as the 2nd choice in the ternary guards against this:

!defaults.slideshowWidth = 
      ? defaults.slideshowWidth = obj.find('img').width()+'px' 
      : defaults.slideshowwidth 

Safer, but perhaps not as nice to look at, and more typing. In practice, I'd probably write

defaults.slideshowWidth = defaults.slideshowWidth 
               || obj.find('img').width()+'px'

PHP parse/syntax errors; and how to solve them

unexpected ':', expecting ',' or ')'

If attempting to use PHP 8's new named parameter functionality in a version of PHP < 8 this error will occur:



  1. Upgrade your version of PHP tp PHP 8.8.0 or higher
  2. Do not use named parameters (pass the parameters in in the order they are expected)

Chrome: Uncaught SyntaxError: Unexpected end of input

JSHint is good at finding the location of missing brackets or bad syntax.

Python: SyntaxError: keyword can't be an expression

It's python source parser failure on sum.up=False named argument as sum.up is not valid argument name (you can't use dots -- only alphanumerics and underscores in argument names).

C error: Expected expression before int

This is actually a fairly interesting question. It's not as simple as it looks at first. For reference, I'm going to be basing this off of the latest C11 language grammar defined in N1570

I guess the counter-intuitive part of the question is: if this is correct C:

if (a == 1) {
  int b = 10;

then why is this not also correct C?

if (a == 1)
  int b = 10;

I mean, a one-line conditional if statement should be fine either with or without braces, right?

The answer lies in the grammar of the if statement, as defined by the C standard. The relevant parts of the grammar I've quoted below. Succinctly: the int b = 10 line is a declaration, not a statement, and the grammar for the if statement requires a statement after the conditional that it's testing. But if you enclose the declaration in braces, it becomes a statement and everything's well.

And just for the sake of answering the question completely -- this has nothing to do with scope. The b variable that exists inside that scope will be inaccessible from outside of it, but the program is still syntactically correct. Strictly speaking, the compiler shouldn't throw an error on it. Of course, you should be building with -Wall -Werror anyways ;-)

(6.7) declaration:
            declaration-speci?ers init-declarator-listopt ;

(6.7) init-declarator-list:
            init-declarator-list , init-declarator

(6.7) init-declarator:
            declarator = initializer

(6.8) statement:

(6.8.2) compound-statement:
            { block-item-listopt }

(6.8.4) selection-statement:
            if ( expression ) statement
            if ( expression ) statement else statement
            switch ( expression ) statement

Access Form - Syntax error (missing operator) in query expression

I had this same problem. As Dedren says, the problem is not the query, but the form object's control source. Put [] around each objects Control Source. eg: Contol Source: [Product number], Control Source: Salesperson.[Salesperson number], etc.

Makita recomends going to the original table that you are referencing in your query and rename the field so that there are no spaces eg: SalesPersonNumber, ProductNumber, etc. This will solve many future problems as well. Best of Luck!

How to define a two-dimensional array?

Here is a shorter notation for initializing a list of lists:

matrix = [[0]*5 for i in range(5)]

Unfortunately shortening this to something like 5*[5*[0]] doesn't really work because you end up with 5 copies of the same list, so when you modify one of them they all change, for example:

>>> matrix = 5*[5*[0]]
>>> matrix
[[0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]
>>> matrix[4][4] = 2
>>> matrix
[[0, 0, 0, 0, 2], [0, 0, 0, 0, 2], [0, 0, 0, 0, 2], [0, 0, 0, 0, 2], [0, 0, 0, 0, 2]]

Laravel: Error [PDOException]: Could not Find Driver in PostgreSQL

In Linux(Ubuntu) just install the driver like so:

sudo apt-get install php-pgsql

This will install the driver with using your php current version.

PLS-00103: Encountered the symbol when expecting one of the following:

    var_number := 10;

    if var_number > 100 then
        dbms_output.put_line(var_number||' is greater than 100');
    else if var_number < 100 then
        dbms_output.put_line(var_number||' is less than 100');
        dbms_output.put_line(var_number||' is equal to 100');
    end if;
end if;

Visual Studio displaying errors even if projects build

Try hovering with the mouse over the underlined elements. It should normally tell you what the problem. To see a list of all the errors/warnings, go to View => Error List. A table should open on the bottom of the IDE with all the errors/warnings listed.

JavaScript error (Uncaught SyntaxError: Unexpected end of input)

In my case, it was caused by a missing (0) in javascript:void(0) in an anchor.

Notice: Trying to get property of non-object error

The response is an array.


Unexpected token < in first line of HTML

Well... I flipped the internet upside down three times but did not find anything that might help me because it was a Drupal project rather than other scenarios people described.

My problem was that someone in the project added a js which his address was: <script src="http://base_url/?p4sxbt"></script> and it was attached in this way:

    array('scope' => 'footer', 'weight' => 5)

Hope this will help someone in the future.

How can you print multiple variables inside a string using printf?

printf("\nmaximum of %d and %d is = %d",a,b,c);

SyntaxError: cannot assign to operator

Instead of ((t[1])/length) * t[1] += string, you should use string += ((t[1])/length) * t[1]. (The other syntax issue - int is not iterable - will be your exercise to figure out.)

How do I get PHP errors to display?

To display all errors you need to:

1. Have these lines in the PHP script you're calling from the browser (typically index.php):

ini_set('display_errors', '1');

2.(a) Make sure that this script has no syntax errors


2.(b) Set display_errors = On in your php.ini

Otherwise, it can't even run those 2 lines!

You can check for syntax errors in your script by running (at the command line):

php -l index.php

If you include the script from another PHP script then it will display syntax errors in the included script. For example:


ini_set('display_errors', '1');

// Any syntax errors here will result in a blank screen in the browser

include 'my_script.php';


adjfkj // This syntax error will be displayed in the browser

'Syntax Error: invalid syntax' for no apparent reason

You're missing a close paren in this line:


There are three ( and only two ).
I hope This will help you.

syntax error when using command line in python

In order to run scripts, you should write the "python" command in the command prompt, and not within the python shell. also, the file should be at the path you run from in the cli.

Why does the program give "illegal start of type" error?

You have a misplaced closing brace before the return statement.

move column in pandas dataframe

This function will reorder your columns without losing data. Any omitted columns remain in the center of the data set:

def reorder_columns(columns, first_cols=[], last_cols=[], drop_cols=[]):
    columns = list(set(columns) - set(first_cols))
    columns = list(set(columns) - set(drop_cols))
    columns = list(set(columns) - set(last_cols))
    new_order = first_cols + columns + last_cols
    return new_order

Example usage:

my_list = ['first', 'second', 'third', 'fourth', 'fifth', 'sixth']
reorder_columns(my_list, first_cols=['fourth', 'third'], last_cols=['second'], drop_cols=['fifth'])

# Output:
['fourth', 'third', 'first', 'sixth', 'second']

To assign to your dataframe, use:

my_list = df.columns.tolist()
reordered_cols = reorder_columns(my_list, first_cols=['fourth', 'third'], last_cols=['second'], drop_cols=['fifth'])
df = df[reordered_cols]

Error starting Tomcat from NetBeans - '*' is not recognized as an internal or external command

Assuming you are on Windows (this bug is caused by the crappy bat files escaping), It is a bug introduced in the latest versions (7.0.56 and 8.0.14) to workaround another bug. Try to remove the " around the JAVA_OPTS declaration in catalina.bat. It fixed it for me with Tomcat 7.0.56 yesterday.

In 7.0.56 in bin/catalina.bat:179 and 184








For your asterisk, it might only be a configuration of yours somewhere that appends it to the host declaration.

I saw this on Tomcat's bugtracker yesterday but I can't find the link again. Edit Found it!

I hope it fixes your problem.

sqldeveloper error message: Network adapter could not establish the connection error

Re: SQL DevErr:The Network Adapter could not establish the connection VenCode20 Posted: Dec 7, 2011 3:23 AM in response to: MehulDoshi Reply

This worked for me:

Open the "New/Select Database Connection" dialogue and try changing the connection type setting from "Basic" to "TNS" and then selecting the network alias (for me: "ORCL").

How do you change text to bold in Android?

Simply you can do the following:

Set the attribute in XML


Programatically the method is:

TextView Tv = (TextView) findViewById(;

Typeface boldTypeface = Typeface.defaultFromStyle(Typeface.BOLD);


Hope this helps you thank you.

Displaying a message in iOS which has the same functionality as Toast in Android

If you want one with iOS Style, download this framework from Github

iOS Toast Alert View Framework

This examples work on you UIViewController, once you imported the Framework.

Example 1:

let tav = ToastAlertView()
tav.message = "Hey!"
tav.image = UIImage(named: "img1")!
//tav.dismiss() to Hide

Example 2:

//Toast Alert View with Time Dissmis Only
self.showToastAlert("5 Seconds",
                image: UIImage(named: "img1")!,
                hideWithTap: false,
                hideWithTime: true,
                hideTime: 5.0)


Toast Alert View Image Example

Adding parameter to ng-click function inside ng-repeat doesn't seem to work

Above answers are excellent. You can look at the following full code example so that you could exactly know how to use

   var app = angular.module('hyperCrudApp', []);_x000D_
   app.controller('usersCtrl', function($scope, $http) {_x000D_
     $http.get("").then(function (response) {_x000D_
         $scope.users =;_x000D_
          $scope.setKey = function (userId){_x000D_
                localStorage.setItem("userId", userId)_x000D_
              } else {_x000D_
                alert("No support of localStorage")_x000D_
          }//function closed  _x000D_
       color: green;_x000D_
       font-weight: bold;_x000D_
  <!DOCTYPE html>_x000D_
    <meta charset="utf-8">_x000D_
    <meta name="viewport" content="width=device-width, initial-scale=1">_x000D_
    <link rel="stylesheet" href="">_x000D_
    <script src=""></script>_x000D_
    <script src=""></script>_x000D_
    <script src=""></script>_x000D_
    <!-- NAVBAR STARTS -->_x000D_
      <nav class="navbar navbar-default navbar-fixed-top">_x000D_
        <div class="container">_x000D_
          <div class="navbar-header">_x000D_
            <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">_x000D_
              <span class="sr-only">Toggle navigation</span>_x000D_
              <span class="icon-bar"></span>_x000D_
              <span class="icon-bar"></span>_x000D_
              <span class="icon-bar"></span>_x000D_
            <a class="navbar-brand" href="#">HyperCrud</a>_x000D_
          <div id="navbar" class="navbar-collapse collapse">_x000D_
            <ul class="nav navbar-nav">_x000D_
              <li class="active"><a href="/">Home</a></li>_x000D_
              <li><a href="/about/">About</a></li>_x000D_
              <li><a href="/contact/">Contact</a></li>_x000D_
              <li class="dropdown">_x000D_
                <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Apps<span class="caret"></span></a>_x000D_
                <ul class="dropdown-menu">_x000D_
                  <li><a href="/qAlarm/details/">qAlarm &raquo;</a></li>_x000D_
                  <li><a href="/YtEdit/details/">YtEdit &raquo;</a></li>_x000D_
                  <li><a href="/GWeather/details/">GWeather &raquo;</a></li>_x000D_
                  <li role="separator" class="divider"></li>_x000D_
                  <li><a href="/WadStore/details/">WadStore &raquo;</a></li>_x000D_
                  <li><a href="/chatsAll/details/">chatsAll</a></li>_x000D_
            <ul class="nav navbar-nav navbar-right">_x000D_
              <li><a href="/login/">Login</a></li>_x000D_
              <li><a href="/register/">Register</a></li>_x000D_
              <li><a href="/services/">Services<span class="sr-only">(current)</span></a></li>_x000D_
      <!--NAVBAR ENDS-->_x000D_
  <div ng-app="hyperCrudApp" ng-controller="usersCtrl" class="container">_x000D_
    <div class="row">_x000D_
     <div class="col-sm-12 col-md-12">_x000D_
        <h1 id="header"> Users </h1>_x000D_
    <div class="row" >_x000D_
        <!--ITERATING USERS LIST-->_x000D_
      <div class="col-sm-6 col-md-4" ng-repeat="user in users">_x000D_
        <div class="thumbnail">_x000D_
           <img src="" alt="Image - {{}}" class="img-responsive img-circle" style="width: 100px">_x000D_
          <div class="caption">_x000D_
             <p>+91 {{}}</p>_x000D_
            <div class="caption">_x000D_
                <a href="/users/delete/{{}}/" role="button" class="btn btn-danger btn-block" ng-click="setKey(">DELETE</a>_x000D_
                <a href="/users/update/{{}}/" role="button" class="btn btn-success btn-block" ng-click="setKey(">UPDATE</a>_x000D_
        <div class="col-sm-6 col-md-4">_x000D_
          <div class="thumbnail">_x000D_
            <a href="/regiser/">_x000D_
             <img src="" alt="Register Image" class="img-responsive img-circle" style="width: 100%">_x000D_
      <!--ROW ENDS-->_x000D_

Detect if a page has a vertical scrollbar?

I wrote an updated version of Kees C. Bakker's answer:

const hasVerticalScroll = (node) => {
  if (!node) {
    if (window.innerHeight) {
      return document.body.offsetHeight > window.innerHeight
    return (document.documentElement.scrollHeight > document.documentElement.offsetHeight)
      || (document.body.scrollHeight > document.body.offsetHeight)
  return node.scrollHeight > node.offsetHeight

if (hasVerticalScroll(document.querySelector('body'))) {

The function returns true or false depending whether the page has a vertical scrollbar or not.

For example:

const hasVScroll = hasVerticalScroll(document.querySelector('body'))

if (hasVScroll) {
  console.log('HAS SCROLL', hasVScroll)

AngularJS not detecting Access-Control-Allow-Origin header?

Instead of using $http.get('abc/xyz/getSomething') try to use $http.jsonp('abc/xyz/getSomething')

                return $http.jsonp('http://localhost:8080/getNames');

Vue equivalent of setTimeout?

Add bind(this) to your setTimeout callback function

setTimeout(function () {
    this.basketAddSuccess = false
}.bind(this), 2000)

jQuery select change show/hide div event

Nothing new but caching your jQuery collections will have a small perf boost

$(function() {

    var $typeSelector = $('#type');
    var $toggleArea = $('#row_dim');

        if ($typeSelector.val() === 'parcel') {
        else {

And in vanilla JS for super speed:

(function() {

    var typeSelector = document.getElementById('type');
    var toggleArea = document.getElementById('row_dim');

    typeSelector.onchange = function() { = typeSelector.value === 'parcel'
            ? 'block'
            : 'none';


Fastest way to convert Image to Byte array

public static byte[] ReadImageFile(string imageLocation)
        byte[] imageData = null;
        FileInfo fileInfo = new FileInfo(imageLocation);
        long imageFileLength = fileInfo.Length;
        FileStream fs = new FileStream(imageLocation, FileMode.Open, FileAccess.Read);
        BinaryReader br = new BinaryReader(fs);
        imageData = br.ReadBytes((int)imageFileLength);
        return imageData;

How to make multiple divs display in one line but still retain width?

Flex is the better way. Just try..

display: flex;

How to split strings over multiple lines in Bash?

You can use bash arrays

$ str_array=("continuation"


$ echo "${str_array[*]}"
continuation lines

there is an extra space, because (after bash manual):

If the word is double-quoted, ${name[*]} expands to a single word with the value of each array member separated by the first character of the IFS variable

So set IFS='' to get rid of extra space

$ IFS=''
$ echo "${str_array[*]}"

Make view 80% width of parent in React Native

I have an updated solution (late 2019) , to get 80% width of parent Responsively with Hooks it work's even if the device rotate.

You can use Dimensions.get('window').width to get Device Width in this example you can see how you can do it Responsively

import React, { useEffect, useState } from 'react';
import { Dimensions , View , Text , StyleSheet  } from 'react-native';

export default const AwesomeProject() => {
   const [screenData, setScreenData] = useState(Dimensions.get('window').width);

    useEffect(() => {
     const onChange = () => {
     Dimensions.addEventListener('change', onChange);

     return () => {Dimensions.removeEventListener('change', onChange);};

   return (  
          <View style={[styles.container, { width: screenData * 0.8 }]}>
             <Text> I'mAwesome </Text>

const styles = StyleSheet.create({
container: {
     flex: 1,
     alignItems: 'center',
     justifyContent: 'center',
     backgroundColor: '#eee',

"Cloning" row or column vectors

One clean solution is to use NumPy's outer-product function with a vector of ones:

np.outer(np.ones(n), x)

gives n repeating rows. Switch the argument order to get repeating columns. To get an equal number of rows and columns you might do

np.outer(np.ones_like(x), x)

get next sequence value from database using hibernate

If you are using Oracle, consider specifying cache size for the sequence. If you are routinely create objects in batches of 5K, you can just set it to a 1000 or 5000. We did it for the sequence used for the surrogate primary key and were amazed that execution times for an ETL process hand-written in Java dropped in half.

I could not paste formatted code into comment. Here's the sequence DDL:

create sequence seq_mytable_sid 
minvalue 1 
maxvalue 999999999999999999999999999 
increment by 1 
start with 1 
cache 1000 

REST API Login Pattern

Principled Design of the Modern Web Architecture by Roy T. Fielding and Richard N. Taylor, i.e. sequence of works from all REST terminology came from, contains definition of client-server interaction:

All REST interactions are stateless. That is, each request contains all of the information necessary for a connector to understand the request, independent of any requests that may have preceded it.

This restriction accomplishes four functions, 1st and 3rd are important in this particular case:

  • 1st: it removes any need for the connectors to retain application state between requests, thus reducing consumption of physical resources and improving scalability;
  • 3rd: it allows an intermediary to view and understand a request in isolation, which may be necessary when services are dynamically rearranged;

And now lets go back to your security case. Every single request should contains all required information, and authorization/authentication is not an exception. How to achieve this? Literally send all required information over wires with every request.

One of examples how to archeive this is hash-based message authentication code or HMAC. In practice this means adding a hash code of current message to every request. Hash code calculated by cryptographic hash function in combination with a secret cryptographic key. Cryptographic hash function is either predefined or part of code-on-demand REST conception (for example JavaScript). Secret cryptographic key should be provided by server to client as resource, and client uses it to calculate hash code for every request.

There are a lot of examples of HMAC implementations, but I'd like you to pay attention to the following three:

How it works in practice

If client knows the secret key, then it's ready to operate with resources. Otherwise he will be temporarily redirected (status code 307 Temporary Redirect) to authorize and to get secret key, and then redirected back to the original resource. In this case there is no need to know beforehand (i.e. hardcode somewhere) what the URL to authorize the client is, and it possible to adjust this schema with time.

Hope this will helps you to find the proper solution!

Enable SQL Server Broker taking too long

Actually I am preferring to use NEW_BROKER ,it is working fine on all cases:


Can I edit an iPad's host file?

I know it's been a while this has been posted, but with iOS 7.1, a few things have changed.

So far, if you are developing an App, you MUST have a valid SSL certificate recognized by Apple, otherwise you will get an error message on you iDevice. No more self-signed certificates. See here a list:

Additionally, if you are here, it means that you are trying to make you iDevice resolve a name (to your https server), on a test or development environment.

Instead of using squid, which is a great application, you could simply run a very basic DNS server like dnsmasq. It will use your hosts file as a first line of name resolution, so, you can basically fool your iDevice there, saying that is

The configuration file is as simple as 3 to 4 lines, and you can even configure its internal DHCP server if you want.

Here is mine:






Of course you have to configure networking on your iDevice to use that DNS ( in my case), or just start using DHCP from that server anyway, after properly configured.

Additionally, if dnsmasq cannot resolve the name internally, it uses your regular DNS server (like to resolve it for you. VERY simple, elegant, and solved my problems with iDevice App installation in-house.

By the way, solves many name resolution problems with regular macs (OS X) as well.

Now, my rant: bloody Apple. Making a device safe should not include castrating the operating system or the developers.

Running Java Program from Command Line Linux

If your Main class is in a package called FileManagement, then try:

java -cp . FileManagement.Main

in the parent folder of the FileManagement folder.

If your Main class is not in a package (the default package) then cd to the FileManagement folder and try:

java -cp . Main

More info about the CLASSPATH and how the JRE find classes:

How do I interpret precision and scale of a number in a database?

Precision of a number is the number of digits.

Scale of a number is the number of digits after the decimal point.

What is generally implied when setting precision and scale on field definition is that they represent maximum values.

Example, a decimal field defined with precision=5 and scale=2 would allow the following values:

  • 123.45 (p=5,s=2)
  • 12.34 (p=4,s=2)
  • 12345 (p=5,s=0)
  • 123.4 (p=4,s=1)
  • 0 (p=0,s=0)

The following values are not allowed or would cause a data loss:

  • 12.345 (p=5,s=3) => could be truncated into 12.35 (p=4,s=2)
  • 1234.56 (p=6,s=2) => could be truncated into 1234.6 (p=5,s=1)
  • 123.456 (p=6,s=3) => could be truncated into 123.46 (p=5,s=2)
  • 123450 (p=6,s=0) => out of range

Note that the range is generally defined by the precision: |value| < 10^p ...

Comments in Android Layout xml

From Federico Culloca's note:

Also you cannot use them inside tags

Means; you have to put the comment at the top or bottom of the file - all the places you really want to add comments are at least inside the top level layout tag

C++11 thread-safe queue

You may like lfqueue, It’s lock free concurrent queue. I’m currently using it to consuming the queue from multiple incoming calls and works like a charm.

OpenCV error: the function is not implemented

Don't waste your time trying to resolve this issue, this was made clear by the makers themselves. Instead of cv2.imshow() use this:

img = cv2.imread('path_to_image')
plt.imshow(img, cmap = 'gray', interpolation = 'bicubic')
plt.xticks([]), plt.yticks([])  # to hide tick values on X and Y axis

How to style a checkbox using CSS

You can simply use appearance: none on modern browsers, so that there is no default styling and all your styles are applied properly:

input[type=checkbox] {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  display: inline-block;
  width: 2em;
  height: 2em;
  border: 1px solid gray;
  outline: none;
  vertical-align: middle;

input[type=checkbox]:checked {
  background-color: blue;

Bootstrap's JavaScript requires jQuery version 1.9.1 or higher

In my case(Bootstrap) the issue was, having the JQuery 3.0.0 which is also not fine, So using a version which is an earlier version like 2.2.4.

The Error i got was: Bootstrap's JavaScript requires jQuery version 1.9.1 or higher, but lower than version 3

Using any of these CDN below as the source would help if this is the case!

jQuery version 2.2.4:

Hope this helped at least someone!.. :)

Thank you!

What is the purpose of using -pedantic in GCC/G++ compiler?

<-ansi is an obsolete switch that requests the compiler to compile according to the 30-year-old obsolete revision of C standard, ISO/IEC 9899:1990, which is essentially a rebranding of the ANSI standard X3.159-1989 "Programming Language C. Why obsolete? Because after C90 was published by ISO, ISO has been in charge of the C standardization, and any technical corrigenda to C90 have been standardized by ISO. Thus it is more apt to use the -std=c90.

Without this switch, the recent GCC C compilers will conform to the C language standardized in ISO/IEC 9899:2011, or the newest 2018 revision.

Unfortunately there are some lazy compiler vendors that believe it is acceptable to stick to an older obsolete standard revision, for which the standardization document is not even available from standard bodies.

Using the switch helps ensuring that the code should compile in these obsolete compilers.

The -pedantic is an interesting one. In absence of -pedantic, even when a specific standard is requested, GCC will still allow some extensions that are not acceptable in the C standard. Consider for example the program

struct test {
    int zero_size_array[0];

The C11 draft n1570 paragraph says:

In addition to optional type qualifiers and the keyword static, the [ and ] may delimit an expression or *. If they delimit an expression (which specifies the size of an array), the expression shall have an integer type. If the expression is a constant expression, it shall have a value greater than zero.[...]

The C standard requires that the array length be greater than zero; and this paragraph is in the constraints; the standard says the following

A conforming implementation shall produce at least one diagnostic message (identified in an implementation-defined manner) if a preprocessing translation unit or translation unit contains a violation of any syntax rule or constraint, even if the behavior is also explicitly specified as undefined or implementation-defined. Diagnostic messages need not be produced in other circumstances.9)

However, if you compile the program with gcc -c -std=c90 pedantic_test.c, no warning is produced.

-pedantic causes the compiler to actually comply to the C standard; so now it will produce a diagnostic message, as is required by the standard:

gcc -c -pedantic -std=c90 pedantic_test.c
pedantic_test.c:2:9: warning: ISO C forbids zero-size array ‘zero_size_array’ [-Wpedantic]
     int zero_size_array[0];

Thus for maximal portability, specifying the standard revision is not enough, you must also use -pedantic (or -pedantic-errors) to ensure that GCC actually does comply to the letter of the standard.

The last part of the question was about using -ansi with C++. ANSI never standardized the C++ language - only adopting it from ISO, so this makes about as much sense as saying "English as standardized by France". However GCC still seems to accept it for C++, as stupid as it sounds.

SQL Server: Importing database from .mdf?

To perform this operation see the next images:

enter image description here

and next step is add *.mdf file,

very important, the .mdf file must be located in C:......\MSSQL12.SQLEXPRESS\MSSQL\DATA

enter image description here

Now remove the log file

enter image description here

Is it possible to make a Tree View with Angular?

Not complicated.

<div ng-app="Application" ng-controller="TreeController">
                <th>col 1</th>
                <th>col 2</th>
                <th>col 3</th>
        <tbody ng-repeat="item in tree">
            <tr ng-repeat="children in item.child">
                <td style="padding-left:15px;">{{}}</td>

controller code:

angular.module("myApp", []).
controller("TreeController", ['$scope', function ($scope) {
    $scope.tree = [{
        id: 1,
        fname: "tree",
        child: [{
            id: 1,
            fname: "example"
        lname: "grid"


returning a Void object

If you just don't need anything as your type, you can use void. This can be used for implementing functions, or actions. You could then do something like this:

interface Action<T> {
    public T execute();

abstract class VoidAction implements Action<Void> {
    public Void execute() {
        return null;

    abstract void executeInternal();

Or you could omit the abstract class, and do the return null in every action that doesn't require a return value yourself.

You could then use those actions like this:

Given a method

private static <T> T executeAction(Action<T> action) {
    return action.execute();

you can call it like

String result = executeAction(new Action<String>() {
    public String execute() {
        //code here
        return "Return me!";

or, for the void action (note that you're not assigning the result to anything)

executeAction(new VoidAction() {
    public void executeInternal() {
        //code here

Map implementation with duplicate keys

I used this:

java.util.List<java.util.Map.Entry<String,Integer>> pairList= new java.util.ArrayList<>();

Difference between Arrays.asList(array) and new ArrayList<Integer>(Arrays.asList(array))

In response to some comments asking questions about the behaviour of Arrays.asList() since Java 8:

    int[] arr1 = {1,2,3};
       Arrays are objects in Java, internally int[] will be represented by 
       an Integer Array object which when printed on console shall output
       a pattern such as 
       [I@address for 1-dim int array,
       [[I@address for 2-dim int array, 
       [[F@address for 2-dim float array etc. 

       The line below results in Compile time error as Arrays.asList(int[] array)
       returns List<int[]>. The returned list contains only one element 
       and that is the int[] {1,2,3} 
    // List<Integer> list1 = Arrays.asList(arr1);

       Arrays.asList(arr1) is  Arrays$ArrayList object whose only element is int[] array
       so the line below prints [[I@...], where [I@... is the array object.

     This prints [I@..., the actual array object stored as single element 
     in the Arrays$ArrayList object. 

    // prints the contents of array [1,2,3]

    Integer[] arr2 = {1,2,3};
     Arrays.asList(arr) is  Arrays$ArrayList object which is 
     a wrapper list object containing three elements 1,2,3.
     Technically, it is pointing to the original Integer[] array 
    List<Integer> list2 = Arrays.asList(arr2);

    // prints the contents of list [1,2,3]

How to: Add/Remove Class on mouseOver/mouseOut - JQuery .hover?

You are missing the dot on the selector, and you can use toggleClass method on jquery:

  function () {

Add a column in a table in HIVE QL

You cannot add a column with a default value in Hive. You have the right syntax for adding the column ALTER TABLE test1 ADD COLUMNS (access_count1 int);, you just need to get rid of default sum(max_count). No changes to that files backing your table will happen as a result of adding the column. Hive handles the "missing" data by interpreting NULL as the value for every cell in that column.

So now your have the problem of needing to populate the column. Unfortunately in Hive you essentially need to rewrite the whole table, this time with the column populated. It may be easier to rerun your original query with the new column. Or you could add the column to the table you have now, then select all of its columns plus value for the new column.

You also have the option to always COALESCE the column to your desired default and leave it NULL for now. This option fails when you want NULL to have a meaning distinct from your desired default. It also requires you to depend on always remembering to COALESCE.

If you are very confident in your abilities to deal with the files backing Hive, you could also directly alter them to add your default. In general I would recommend against this because most of the time it will be slower and more dangerous. There might be some case where it makes sense though, so I've included this option for completeness.

Can Python test the membership of multiple values in a list?

Another way to do it:

>>> set(['a','b']).issubset( ['b','a','foo','bar'] )

Change project name on Android Studio

What works for me is,

Go To Build.gradle Change ApplicationId & sync project.

Right click on your project > Rename > Rename Package.

Run your app and boom.

Hope this works as did for me

Error on line 2 at column 1: Extra content at the end of the document

You might have output (maybe error/debug output) that precedes your call to

header("Content-type: text/xml");

Therefore, the content being delivered to the browser is not "xml"... that's what the error message is trying to tell you (at least that was the case for me and I had the same error message as you've described).

HttpServletRequest - Get query string parameters, no form data

I am afraid there is no way to get the query string parameters parsed separately from the post parameters. BTW the fact that such API absent may mean that probably you should check your design. Why are you using query string when sending POST? If you really want to send more data into URL use REST-like convention, e.g. instead of sending


Python, how to read bytes from file and save it?

Here's how to do it with the basic file operations in Python. This opens one file, reads the data into memory, then opens the second file and writes it out.

in_file = open("in-file", "rb") # opening for [r]eading as [b]inary
data = # if you only wanted to read 512 bytes, do .read(512)

out_file = open("out-file", "wb") # open for [w]riting as [b]inary

We can do this more succinctly by using the with keyboard to handle closing the file.

with open("in-file", "rb") as in_file, open("out-file", "wb") as out_file:

If you don't want to store the entire file in memory, you can transfer it in pieces.

piece_size = 4096 # 4 KiB

with open("in-file", "rb") as in_file, open("out-file", "wb") as out_file:
    while True:
        piece =

        if piece == "":
            break # end of file


Android - get children inside a View?

I'm just going to provide this answer as an alternative @IHeartAndroid's recursive algorithm for discovering all child Views in a view hierarchy. Note that at the time of this writing, the recursive solution is flawed in that it will contains duplicates in its result.

For those who have trouble wrapping their head around recursion, here's a non-recursive alternative. You get bonus points for realizing this is also a breadth-first search alternative to the depth-first approach of the recursive solution.

private List<View> getAllChildrenBFS(View v) {
    List<View> visited = new ArrayList<View>();
    List<View> unvisited = new ArrayList<View>();

    while (!unvisited.isEmpty()) {
        View child = unvisited.remove(0);
        if (!(child instanceof ViewGroup)) continue;
        ViewGroup group = (ViewGroup) child;
        final int childCount = group.getChildCount();
        for (int i=0; i<childCount; i++) unvisited.add(group.getChildAt(i));

    return visited;

A couple of quick tests (nothing formal) suggest this alternative is also faster, although that has most likely to do with the number of new ArrayList instances the other answer creates. Also, results may vary based on how vertical/horizontal the view hierarchy is.

Cross-posted from: Android | Get all children elements of a ViewGroup

how to change onclick event with jquery?

Updating this post (2015) : unbind/bind should not be used anymore with jQuery 1.7+. Use instead the function off(). Example :

    //Other code etc.

Be sure that you call a non-parameter function in .click, otherwise it will be ignored.

Best way to check if object exists in Entity Framework?

From a performance point of view, I guess that a direct SQL query using the EXISTS command would be appropriate. See here for how to execute SQL directly in Entity Framework:

How to Populate a DataTable from a Stored Procedure

Use an SqlDataAdapter instead, it's much easier and you don't need to define the column names yourself, it will get the column names from the query results:

using (SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings["DB"].ConnectionString))
    using (SqlCommand cmd = new SqlCommand("usp_GetABCD", sqlcon))
        cmd.CommandType = CommandType.StoredProcedure;

        using (SqlDataAdapter da = new SqlDataAdapter(cmd))
            DataTable dt = new DataTable();


CSS: How to change colour of active navigation page menu

I think you are getting confused about what the a:active CSS selector does. This will only change the colour of your link when you click it (and only for the duration of the click i.e. how long your mouse button stays down). What you need to do is introduce a new class e.g. .selected into your CSS and when you select a link, update the selected menu item with new class e.g.

<div class="menuBar">
        <li class="selected"><a href="index.php">HOME</a></li>
        <li><a href="two.php">PORTFOLIO</a></li>

// specific CSS for your menu
div.menuBar li.selected a { color: #FF0000; } 
// more general CSS
li.selected a { color: #FF0000; }

You will need to update your template page to take in a selectedPage parameter.

How can I replace newline or \r\n with <br/>?

nl2br() worked for me, but I needed to wrap the variable with double quotes:

This works:

$description = nl2br("$description");

This doesn't work:

$description = nl2br($description);

Does static constexpr variable inside a function make sense?

The short answer is that not only is static useful, it is pretty well always going to be desired.

First, note that static and constexpr are completely independent of each other. static defines the object's lifetime during execution; constexpr specifies that the object should be available during compilation. Compilation and execution are disjoint and discontiguous, both in time and space. So once the program is compiled, constexpr is no longer relevant.

Every variable declared constexpr is implicitly const but const and static are almost orthogonal (except for the interaction with static const integers.)

The C++ object model (§1.9) requires that all objects other than bit-fields occupy at least one byte of memory and have addresses; furthermore all such objects observable in a program at a given moment must have distinct addresses (paragraph 6). This does not quite require the compiler to create a new array on the stack for every invocation of a function with a local non-static const array, because the compiler could take refuge in the as-if principle provided it can prove that no other such object can be observed.

That's not going to be easy to prove, unfortunately, unless the function is trivial (for example, it does not call any other function whose body is not visible within the translation unit) because arrays, more or less by definition, are addresses. So in most cases, the non-static const(expr) array will have to be recreated on the stack at every invocation, which defeats the point of being able to compute it at compile time.

On the other hand, a local static const object is shared by all observers, and furthermore may be initialized even if the function it is defined in is never called. So none of the above applies, and a compiler is free not only to generate only a single instance of it; it is free to generate a single instance of it in read-only storage.

So you should definitely use static constexpr in your example.

However, there is one case where you wouldn't want to use static constexpr. Unless a constexpr declared object is either ODR-used or declared static, the compiler is free to not include it at all. That's pretty useful, because it allows the use of compile-time temporary constexpr arrays without polluting the compiled program with unnecessary bytes. In that case, you would clearly not want to use static, since static is likely to force the object to exist at runtime.

Mockito: InvalidUseOfMatchersException

Inspite of using all the matchers, I was getting the same issue:

Invalid use of argument matchers!
1 matchers expected, 3 recorded:"

It took me little while to figure this out that the method I was trying to mock was a static method of a class(say Xyz.class) which contains only static method and I forgot to write following line:


May be it will help others as it may also be the cause of the issue.

PHP Fatal error: Uncaught exception 'Exception'

This is expected behavior for an uncaught exception with display_errors off.

Your options here are to turn on display_errors via php or in the ini file or catch and output the exception.

 ini_set("display_errors", 1);


     // code that may throw an exception
 } catch(Exception $e){
     echo $e->getMessage();

If you are throwing exceptions, the intention is that somewhere further down the line something will catch and deal with it. If not it is a server error (500).

Another option for you would be to use set_exception_handler to set a default error handler for your script.

 function default_exception_handler(Exception $e){
          // show something to the user letting them know we fell down
          echo "<h2>Something Bad Happened</h2>";
          echo "<p>We fill find the person responsible and have them shot</p>";
          // do some logging for the exception and call the kill_programmer function.

Display unescaped HTML in Vue.js

Vue by default ships with the v-html directive to show it, you bind it onto the element itself rather than using the normal moustache binding for string variables.

So for your specific example you would need:

<div id="logapp">    
            <tr v-repeat="logs">
                <td v-html="fail"></td>
                <td v-html="type"></td>
                <td v-html="description"></td>
                <td v-html="stamp"></td>
                <td v-html="id"></td>

Access to file download dialog in Firefox

I have a solution for this issue, check the code:

FirefoxProfile firefoxProfile = new FirefoxProfile();


WebDriver driver = new FirefoxDriver(firefoxProfile);//new RemoteWebDriver(new URL("http://localhost:4444/wd/hub"), capability);


Matrix multiplication in OpenCV

You say that the matrices are the same dimensions, and yet you are trying to perform matrix multiplication on them. Multiplication of matrices with the same dimension is only possible if they are square. In your case, you get an assertion error, because the dimensions are not square. You have to be careful when multiplying matrices, as there are two possible meanings of multiply.

Matrix multiplication is where two matrices are multiplied directly. This operation multiplies matrix A of size [a x b] with matrix B of size [b x c] to produce matrix C of size [a x c]. In OpenCV it is achieved using the simple * operator:

C = A * B

Element-wise multiplication is where each pixel in the output matrix is formed by multiplying that pixel in matrix A by its corresponding entry in matrix B. The input matrices should be the same size, and the output will be the same size as well. This is achieved using the mul() function:

output = A.mul(B);

Setting the default Java character encoding

Unfortunately, the file.encoding property has to be specified as the JVM starts up; by the time your main method is entered, the character encoding used by String.getBytes() and the default constructors of InputStreamReader and OutputStreamWriter has been permanently cached.

As Edward Grech points out, in a special case like this, the environment variable JAVA_TOOL_OPTIONS can be used to specify this property, but it's normally done like this:

java -Dfile.encoding=UTF-8 … com.x.Main

Charset.defaultCharset() will reflect changes to the file.encoding property, but most of the code in the core Java libraries that need to determine the default character encoding do not use this mechanism.

When you are encoding or decoding, you can query the file.encoding property or Charset.defaultCharset() to find the current default encoding, and use the appropriate method or constructor overload to specify it.

How to include a font .ttf using CSS?

Did you try format?

@font-face {
  font-family: 'The name of the Font Family Here';
  src: URL('font.ttf') format('truetype');

Read this article:

Also, might depend on browser as well.

How can I create numbered map markers in Google Maps V3?

How about this? (year 2015)

1) Get a custom marker image.

var imageObj = new Image();
    imageObj.src = "/markers/blank_pin.png"; 

2) Create a canvas in RAM and draw this image on it

imageObj.onload = function(){
    var canvas = document.createElement('canvas');
    var context = canvas.getContext("2d");
    context.drawImage(imageObj, 0, 0);

3) Write anything above it

context.font = "40px Arial";
context.fillText("54", 17, 55);

4) Get raw data from canvas and provide it to Google API instead of URL

var image = {
    url: canvas.toDataURL(),
 new google.maps.Marker({
    position: position,
    map: map,
    icon: image

enter image description here

Full code:

function addComplexMarker(map, position, label, callback){
    var canvas = document.createElement('canvas');
    var context = canvas.getContext("2d");
    var imageObj = new Image();
    imageObj.src = "/markers/blank_pin.png";
    imageObj.onload = function(){
        context.drawImage(imageObj, 0, 0);

        //Adjustable parameters
        context.font = "40px Arial";
        context.fillText(label, 17, 55);

        var image = {
            url: canvas.toDataURL(),
            size: new google.maps.Size(80, 104),
            origin: new google.maps.Point(0,0),
            anchor: new google.maps.Point(40, 104)
        // the clickable region of the icon.
        var shape = {
            coords: [1, 1, 1, 104, 80, 104, 80 , 1],
            type: 'poly'
        var marker = new google.maps.Marker({
            position: position,
            map: map,
            labelAnchor: new google.maps.Point(3, 30),
            icon: image,
            shape: shape,
            zIndex: 9999
        callback && callback(marker)

What SOAP client libraries exist for Python, and where is the documentation for them?

We'd used SOAPpy from Python Web Services, but it seems that ZSI (same source) is replacing it.

How to know what the 'errno' means?

This is faster than looking up the code in errno.h, shorter than most solutions posted here and it does not require installation of third party tools:

perl -E 'say $!=shift' 2


No such file or directory

How to get String Array from arrays.xml file

You can't initialize your testArray field this way, because the application resources still aren't ready.

Just change the code to:


import android.os.Bundle;
import android.widget.ArrayAdapter;

public class Episode7 extends ListActivity {
    String[] mTestArray;

    /** Called when the activity is first created. */
    protected void onCreate(Bundle savedInstanceState) {

        // Create an ArrayAdapter that will contain all list items
        ArrayAdapter<String> adapter;

        mTestArray = getResources().getStringArray(R.array.testArray);    

        /* Assign the name array to that adapter and 
        also choose a simple layout for the list items */ 
        adapter = new ArrayAdapter<String>(

        // Assign the adapter to this ListActivity

How to parse a JSON string into JsonNode in Jackson?

New approach to old question. A solution that works from java 9+

ObjectNode agencyNode = new ObjectMapper().valueToTree(Map.of("key", "value"));

is more readable and maintainable for complex objects. Ej

Map<String, Object> agencyMap = Map.of(
        "name", "Agencia Prueba",
        "phone1", "1198788373",
        "address", "Larrea 45 e/ calligaris y paris",
        "number", 267,
        "enable", true,
        "location", Map.of("id", 54),
        "responsible", Set.of(Map.of("id", 405)),
        "sellers", List.of(Map.of("id", 605))
ObjectNode agencyNode = new ObjectMapper().valueToTree(agencyMap);

Convert JSON array to an HTML table in jQuery

One simple way of doing this is:

var data = [{_x000D_
  "Total": 34,_x000D_
  "Version": "1.0.4",_x000D_
  "Office": "New York"_x000D_
}, {_x000D_
  "Total": 67,_x000D_
  "Version": "1.1.0",_x000D_
  "Office": "Paris"_x000D_
function drawTable(data) {_x000D_
  // Get Table headers and print_x000D_
  var head = $("<tr />")_x000D_
  for (var j = 0; j < Object.keys(data[0]).length; j++) {_x000D_
    head.append($("<th>" + Object.keys(data[0])[j] + "</th>"));_x000D_
  // Print the content of rows in DataTable_x000D_
  for (var i = 0; i < data.length; i++) {_x000D_
function drawRow(rowData) {_x000D_
  var row = $("<tr />")_x000D_
  row.append($("<td>" + rowData["Total"] + "</td>"));_x000D_
  row.append($("<td>" + rowData["Version"] + "</td>"));_x000D_
  row.append($("<td>" + rowData["Office"] + "</td>"));_x000D_
table {_x000D_
  border: 1px solid #666;_x000D_
  width: 100%;_x000D_
  text-align: center;_x000D_
th {_x000D_
  background: #f8f8f8;_x000D_
  font-weight: bold;_x000D_
  padding: 2px;_x000D_
<script src=""></script>_x000D_
<table id="DataTable"></table>

how to set background image in submit button?

You can try the following code:

background-image:url('url of your image') 10px 10px no-repeat

Benefits of inline functions in C++?


  • By inlining your code where it is needed, your program will spend less time in the function call and return parts. It is supposed to make your code go faster, even as it goes larger (see below). Inlining trivial accessors could be an example of effective inlining.
  • By marking it as inline, you can put a function definition in a header file (i.e. it can be included in multiple compilation unit, without the linker complaining)


  • It can make your code larger (i.e. if you use inline for non-trivial functions). As such, it could provoke paging and defeat optimizations from the compiler.
  • It slightly breaks your encapsulation because it exposes the internal of your object processing (but then, every "private" member would, too). This means you must not use inlining in a PImpl pattern.
  • It slightly breaks your encapsulation 2: C++ inlining is resolved at compile time. Which means that should you change the code of the inlined function, you would need to recompile all the code using it to be sure it will be updated (for the same reason, I avoid default values for function parameters)
  • When used in a header, it makes your header file larger, and thus, will dilute interesting informations (like the list of a class methods) with code the user don't care about (this is the reason that I declare inlined functions inside a class, but will define it in an header after the class body, and never inside the class body).

Inlining Magic

  • The compiler may or may not inline the functions you marked as inline; it may also decide to inline functions not marked as inline at compilation or linking time.
  • Inline works like a copy/paste controlled by the compiler, which is quite different from a pre-processor macro: The macro will be forcibly inlined, will pollute all the namespaces and code, won't be easily debuggable, and will be done even if the compiler would have ruled it as inefficient.
  • Every method of a class defined inside the body of the class itself is considered as "inlined" (even if the compiler can still decide to not inline it
  • Virtual methods are not supposed to be inlinable. Still, sometimes, when the compiler can know for sure the type of the object (i.e. the object was declared and constructed inside the same function body), even a virtual function will be inlined because the compiler knows exactly the type of the object.
  • Template methods/functions are not always inlined (their presence in an header will not make them automatically inline).
  • The next step after "inline" is template metaprograming . I.e. By "inlining" your code at compile time, sometimes, the compiler can deduce the final result of a function... So a complex algorithm can sometimes be reduced to a kind of return 42 ; statement. This is for me extreme inlining. It happens rarely in real life, it makes compilation time longer, will not bloat your code, and will make your code faster. But like the grail, don't try to apply it everywhere because most processing cannot be resolved this way... Still, this is cool anyway...

How can I get useful error messages in PHP?

The two key lines you need to get useful errors out of PHP are:


As pointed out by other contributors, these are switched off by default for security reasons. As a useful tip - when you're setting up your site it's handy to do a switch for your different environments so that these errors are ON by default in your local and development environments. This can be achieved with the following code (ideally in your index.php or config file so this is active from the start):

    // local
    case '':
    // dev
    case '':
    case '':

What is the best way to conditionally apply attributes in AngularJS?

I am using the following to conditionally set the class attr when ng-class can't be used (for example when styling SVG):

ng-attr-class="{{someBoolean && 'class-when-true' || 'class-when-false' }}"

The same approach should work for other attribute types.

(I think you need to be on latest unstable Angular to use ng-attr-, I'm currently on 1.1.4)

python time + timedelta equivalent

The solution is in the link that you provided in your question:

datetime.combine(, time()) + timedelta(hours=1)

Full example:

from datetime import date, datetime, time, timedelta

dt = datetime.combine(, time(23, 55)) + timedelta(minutes=30)
print dt.time()



Android: show/hide a view using an animation

I created an extension for RelativeLayout that shows/hides Layouts with animations. It can extend any kind of View to gain these features.

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.AnimationUtils;
import android.widget.RelativeLayout;

public class AnimatingRelativeLayout extends RelativeLayout
    Context context;
    Animation inAnimation;
    Animation outAnimation;

    public AnimatingRelativeLayout(Context context)
        this.context = context;


    public AnimatingRelativeLayout(Context context, AttributeSet attrs)
        super(context, attrs);
        this.context = context;

    public AnimatingRelativeLayout(Context context, AttributeSet attrs, int defStyle)
        super(context, attrs, defStyle);
        this.context = context;

    private void initAnimations()
        inAnimation = (AnimationSet) AnimationUtils.loadAnimation(context, R.anim.in_animation);
        outAnimation = (Animation) AnimationUtils.loadAnimation(context, R.anim.out_animation);

    public void show()
        if (isVisible()) return;

    public void show(boolean withAnimation)
        if (withAnimation) this.startAnimation(inAnimation);

    public void hide()
        if (!isVisible()) return;

    public void hide(boolean withAnimation)
        if (withAnimation) this.startAnimation(outAnimation);

    public boolean isVisible()
        return (this.getVisibility() == View.VISIBLE);

    public void overrideDefaultInAnimation(Animation inAnimation)
        this.inAnimation = inAnimation;

    public void overrideDefaultOutAnimation(Animation outAnimation)
        this.outAnimation = outAnimation;

You can override the original Animations using overrideDefaultInAnimation and overrideDefaultOutAnimation

My original Animations were fadeIn/Out, I am adding XML animation files for Translating in/out of the screen (Translate to top and from top)


    <?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android=""
    android:toYDelta="0" />


  <?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android=""
    android:toYDelta="-100%p" />

What is the point of WORKDIR on Dockerfile?

You can think of WORKDIR like a cd inside the container (it affects commands that come later in the Dockerfile, like the RUN command). If you removed WORKDIR in your example above, RUN npm install wouldn't work because you would not be in the /usr/src/app directory inside your container.

I don't see how this would be related to where you put your Dockerfile (since your Dockerfile location on the host machine has nothing to do with the pwd inside the container). You can put the Dockerfile wherever you'd like in your project. However, the first argument to COPY is a relative path, so if you move your Dockerfile you may need to update those COPY commands.

Remove non-ASCII characters from CSV

I tried all the solutions and nothing worked. The following, however, does:

tr -cd '\11\12\15\40-\176'

Which I found here:

My problem needed it in a series of piped programs, not directly from a file, so modify as needed.

How to round up integer division and have int result in Java?

To round up an integer division you can use

import static java.lang.Math.abs;

public static long roundUp(long num, long divisor) {
    int sign = (num > 0 ? 1 : -1) * (divisor > 0 ? 1 : -1);
    return sign * (abs(num) + abs(divisor) - 1) / abs(divisor);

or if both numbers are positive

public static long roundUp(long num, long divisor) {
    return (num + divisor - 1) / divisor;

Where does the slf4j log file get saved?

slf4j is only an API. You should have a concrete implementation (for example log4j). This concrete implementation has a config file which tells you where to store the logs.

enter image description here

When slf4j catches a log messages with a logger, it is given to an appender which decides what to do with the message. By default, the ConsoleAppender displays the message in the console.

The default configuration file is :

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">

    <!-- By default => console -->
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>

    <Root level="error">
      <AppenderRef ref="Console"/>

If you put a configuration file available in the classpath, then your concrete implementation (in your case, log4j) will find and use it. See Log4J documentation.

Example of file appender :

<File name="File" fileName="${filename}">
    <pattern>%d %p %C{1.} [%t] %m%n</pattern>


Complete example with a file appender :

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">

    <File name="File" fileName="${filename}">
        <pattern>%d %p %C{1.} [%t] %m%n</pattern>

    <Root level="error">
      <AppenderRef ref="File"/>


C#/Linq: Apply a mapping function to each element in an IEnumerable?

You can just use the Select() extension method:

IEnumerable<int> integers = new List<int>() { 1, 2, 3, 4, 5 };
IEnumerable<string> strings = integers.Select(i => i.ToString());

Or in LINQ syntax:

IEnumerable<int> integers = new List<int>() { 1, 2, 3, 4, 5 };

var strings = from i in integers
              select i.ToString();

Tensorflow: Using Adam optimizer

I was having a similar problem. (No problems training with GradientDescent optimizer, but error raised when using to Adam Optimizer, or any other optimizer with its own variables)

Changing to an interactive session solved this problem for me.

sess = tf.Session()


sess = tf.InteractiveSession()

Need to install urllib2 for Python 3.5.1

Acording to the docs:

Note The urllib2 module has been split across several modules in Python 3 named urllib.request and urllib.error. The 2to3 tool will automatically adapt imports when converting your sources to Python 3.

So it appears that it is impossible to do what you want but you can use appropriate python3 functions from urllib.request.

Java: how can I split an ArrayList in multiple small ArrayLists?

You need to know the chunk size by which you're dividing your list. Say you have a list of 108 entries and you need a chunk size of 25. Thus you will end up with 5 lists:

  • 4 having 25 entries each;
  • 1 (the fifth) having 8 elements.


public static void main(String[] args) {

        List<Integer> list = new ArrayList<Integer>();
        for (int i=0; i<108; i++){
        int size= list.size();
        int j=0;
                List< List<Integer> > splittedList = new ArrayList<List<Integer>>()  ;
                List<Integer> tempList = new ArrayList<Integer>();
            // chunk of 25 created and clearing tempList
            tempList = null;
            //intializing it again for new chunk 
            tempList = new ArrayList<Integer>();
            //adding the remaining enteries 
        for (int k=0;k<splittedList.size(); k++){
            //(k+1) because we started from k=0
            System.out.println("Chunk number: "+(k+1)+" has elements = "+splittedList.get(k).size());

COLLATION 'utf8_general_ci' is not valid for CHARACTER SET 'latin1'

In my case I created a database and gave the collation 'utf8_general_ci' but the required collation was 'latin1'. After changing my collation type to latin1_bin the error was gone.

How does one reorder columns in a data frame?

dplyr version 1.0.0 includes the relocate() function to easily reorder columns:

dat <- data.frame(Time=c(1,2), In=c(2,3), Out=c(3,4), Files=c(4,5))

library(dplyr) # from version 1.0.0 only

dat %>%
  relocate(Out, .before = In)


dat %>%
  relocate(Out, .after = Time)

How to get base URL in Web API controller?

In ASP.NET Core ApiController the Request property is only the message. But there is still Context.Request where you can get expected info. Personally I use this extension method:

public static string GetBaseUrl(this HttpRequest request)
    // SSL offloading
    var scheme = request.Host.Host.Contains("localhost") ? request.Scheme : "https";
    return $"{scheme}://{request.Host}{request.PathBase}";

Code for best fit straight line of a scatter plot in python

A one-line version of this excellent answer to plot the line of best fit is:

plt.plot(np.unique(x), np.poly1d(np.polyfit(x, y, 1))(np.unique(x)))

Using np.unique(x) instead of x handles the case where x isn't sorted or has duplicate values.

Populating a database in a Laravel migration file

Another clean way to do it is to define a private method which create instance et persist concerned Model.

public function up()
    Schema::create('roles', function (Blueprint $table) {
        $table->string('label', 256);

    $this->postCreate('admin', 'user');

private function postCreate(string ...$roles)  {
    foreach ($roles as $role) {
        $model = new Role();
        $model->setAttribute('label', $role);

With this solution, timestamps fields will be generated by Eloquent.

EDIT: it's better to use seeder system to disctinct database structure generation and database population.

ExecuteNonQuery doesn't return results

Because the SET NOCOUNT option is set to on. Remove the line "SET NOCOUNT ON;" in your query or stored procedure.

See more at SqlCommand.ExecuteNonQuery() returns -1 when doing Insert / Update / Delete.

mailto link with HTML body

Thunderbird supports html-body: mailto:[email protected]?subject=Me&html-body=<b>ME</b>

How do I parse JSON with Objective-C?

  1. I recommend and use TouchJSON for parsing JSON.
  2. To answer your comment to Alex. Here's quick code that should allow you to get the fields like activity_details, last_name, etc. from the json dictionary that is returned:

    NSDictionary *userinfo=[jsondic valueforKey:@"#data"];
    NSDictionary *user;
    NSInteger i = 0;
    NSString *skey;
    if(userinfo != nil){
        for( i = 0; i < [userinfo count]; i++ ) {
                skey = [NSString stringWithFormat:@"%d",i];
                skey = @"";
            user = [userinfo objectForKey:skey];
            NSLog(@"activity_details:%@",[user objectForKey:@"activity_details"]);
            NSLog(@"last_name:%@",[user objectForKey:@"last_name"]);
            NSLog(@"first_name:%@",[user objectForKey:@"first_name"]);
            NSLog(@"photo_url:%@",[user objectForKey:@"photo_url"]);

Can there be an apostrophe in an email address?

Yes, according to RFC 3696 apostrophes are valid as long as they come before the @ symbol.

receiving json and deserializing as List of object at spring mvc controller

For me below code worked, first sending json string with proper headers

        type: "POST",
        url : 'save',
        data : JSON.stringify(valObject),
        contentType:"application/json; charset=utf-8",
        success : function(resp){
        error : function(resp){

And then on Spring side -

@RequestMapping(value = "/save", 
                method = RequestMethod.POST,
public @ResponseBody String  save(@RequestBody ArrayList<KeyValue> keyValList) {
    //Saving call goes here
    return "";

Here KeyValue is simple pojo that corresponds to your JSON structure also you can add produces as you wish, I am simply returning string.

My json object is like this -


Python3 integer division

Try this:

a = 1
b = 2
int_div  = a // b

The view 'Index' or its master was not found.

The problem was that I used MvcRoute.MappUrl from MvcContrib to route the context.Routes.

It seems that MvcContrib routing mapper was uncomfortable with area routing.

How do you use "git --bare init" repository?

I'm adding this answer because after arriving here (with the same question), none of the answers really describe all the required steps needed to go from nothing to a fully usable remote (bare) repo.

Note: this example uses local paths for the location of the bare repo, but other git protocols (like SSH indicated by the OP) should work just fine.

I've tried to add some notes along the way for those less familiar with git.

1. Initialise the bare repo...

> git init --bare /path/to/bare/repo.git
Initialised empty Git repository in /path/to/bare/repo.git/

This creates a folder (repo.git) and populates it with git files representing a git repo. As it stands, this repo is useless - it has no commits and more importantly, no branches. Although you can clone this repo, you cannot pull from it.

Next, we need to create a working folder. There are a couple of ways of doing this, depending upon whether you have existing files.

2a. Create a new working folder (no existing files) by cloning the empty repo

git clone /path/to/bare/repo.git /path/to/work
Cloning into '/path/to/work'...
warning: You appear to have cloned an empty repository.

This command will only work if /path/to/work does not exist or is an empty folder. Take note of the warning - at this stage, you still don't have anything useful. If you cd /path/to/work and run git status, you'll get something like:

On branch master

Initial commit

nothing to commit (create/copy files and use "git add" to track)

but this is a lie. You are not really on branch master (because git branch returns nothing) and so far, there are no commits.

Next, copy/move/create some files in the working folder, add them to git and create the first commit.

> cd /path/to/work
> echo 123 > afile.txt
> git add .
> git config --local adelphus
> git config --local [email protected]
> git commit -m "added afile"
[master (root-commit) 614ab02] added afile
 1 file changed, 1 insertion(+)
 create mode 100644 afile.txt

The git config commands are only needed if you haven't already told git who you are. Note that if you now run git branch, you'll now see the master branch listed. Now run git status:

On branch master
Your branch is based on 'origin/master', but the upstream is gone.
  (use "git branch --unset-upstream" to fixup)

nothing to commit, working directory clean

This is also misleading - upstream has not "gone", it just hasn't been created yet and git branch --unset-upstream will not help. But that's OK, now that we have our first commit, we can push and master will be created on the bare repo.

> git push origin master
Counting objects: 3, done.
Writing objects: 100% (3/3), 207 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To /path/to/bare/repo.git
 * [new branch]      master -> master

At this point, we have a fully functional bare repo which can be cloned elsewhere on a master branch as well as a local working copy which can pull and push.

> git pull
Already up-to-date.
> git push origin master
Everything up-to-date

2b. Create a working folder from existing files If you already have a folder with files in it (so you cannot clone into it), you can initialise a new git repo, add a first commit and then link it to the bare repo afterwards.

> cd /path/to/work_with_stuff
> git init 
Initialised empty Git repository in /path/to/work_with_stuff
> git add .
# add git config stuff if needed
> git commit -m "added stuff"

[master (root-commit) 614ab02] added stuff
 20 files changed, 1431 insertions(+)
 create mode 100644 stuff.txt

At this point we have our first commit and a local master branch which we need to turn into a remote-tracked upstream branch.

> git remote add origin /path/to/bare/repo.git
> git push -u origin master
Counting objects: 31, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (31/31), done.
Writing objects: 100% (31/31), 43.23 KiB | 0 bytes/s, done.
Total 31 (delta 11), reused 0 (delta 0)
To /path/to/bare/repo.git
 * [new branch]      master -> master
Branch master set up to track remote branch master from origin.

Note the -u flag on git push to set the (new) tracked upstream branch. Just as before, we now have a fully functional bare repo which can be cloned elsewhere on a master branch as well as a local working copy which can pull and push.

All this may seem obvious to some, but git confuses me at the best of times (it's error and status messages really need some rework) - hopefully, this will help others.

Set transparent background of an imageview on Android

Another working option I came across is to set android:background="@null"

Internet Access in Ubuntu on VirtualBox

I could get away with the following solution (works with Ubuntu 14 guest VM on Windows 7 host or Ubuntu 9.10 Casper guest VM on host Windows XP x86):

  1. Go to network connections -> Virtual Box Host-Only Network -> Select "Properties"
  2. Check VirtualBox Bridged Networking Driver
  3. Come to VirtualBox Manager, choose the network adapter as Bridged Adapter and Name to the device in Step #1.
  4. Restart the VM.

Python convert tuple to string

Use str.join:

>>> tup = ('a', 'b', 'c', 'd', 'g', 'x', 'r', 'e')
>>> ''.join(tup)
>>> help(str.join)
Help on method_descriptor:

    S.join(iterable) -> str

    Return a string which is the concatenation of the strings in the
    iterable.  The separator between elements is S.


Go To Definition: "Cannot navigate to the symbol under the caret."

I've done all things above but my problem did not solve (trying to open project by VS 2017),

after that I realized that the problem was my csproj file. My project (mvc)

was created by VS 2015... So I edit my csproj file and replace

<Import Project="..\packages\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.1.0.0\build\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.props" Condition="Exists('..\packages\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.1.0.0\build\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.props')" />

by this :

<Import Project="..\packages\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.1.0.7\build\net45\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.props" Condition="Exists('..\packages\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.1.0.7\build\net45\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.props')" />

It was all about the version of DotNetCompilerPlatform.

(the way that I understood this issue was that I created new mvc project by VS 2017 and compared both csproj files - the new one and the one that created by VS 2015 - )

Additional related info by (since answers are locked)

For me (VS2019 opening an older solution) it was only affecting one project in the solution. The Imports looked like this:

<Import Project="..\packages\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.1.0.0\build\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.props" Condition="Exists('..\packages\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.1.0.0\build\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.props')" />
<Import Project="..\packages\Microsoft.Net.Compilers.1.0.0\build\Microsoft.Net.Compilers.props" Condition="Exists('..\packages\Microsoft.Net.Compilers.1.0.0\build\Microsoft.Net.Compilers.props')" />
<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />

The working projects only had the

<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />

line, so I removed the first 2 and intelisense / go to definition etc. started working again.

HOWEVER the web project now wouldn't run due to missing Roslyn csc compiler.

In the end the solution that worked overall was to update the Microsoft.CodeDom.Providers.DotNetCompilerPlatform and Microsoft.Net.Compilers Nuget packages for the project.

Finding an elements XPath using IE Developer tool

You can find/debug XPath/CSS locators in the IE as well as in different browsers with the tool called SWD Page Recorder

The only restrictions/limitations:

  1. The browser should be started from the tool
  2. Internet Explorer Driver Server - IEDriverServer.exe - should be downloaded separately and placed near SwdPageRecorder.exe

Best way to make a shell script daemon?

$ ( cd /; umask 0; setsid </dev/null &>/dev/null & ) &

Android: ScrollView force to bottom

Here is some other ways to scroll to bottom

fun ScrollView.scrollToBottom() {
    // use this for scroll immediately
    scrollTo(0, this.getChildAt(0).height) 

    // or this for smooth scroll
    //smoothScrollBy(0, this.getChildAt(0).height)

    // or this for **very** smooth scroll
    //ObjectAnimator.ofInt(this, "scrollY", this.getChildAt(0).height).setDuration(2000).start()


If you scrollview already laid out


If your scrollview is not finish laid out (eg: you scroll to bottom in Activity onCreate method ...) { 

MySQL select all rows from last month until (now() - 1 month), for comparative purposes

My solution was to avoid using NOW() when writing sql with your programming language, and substitute with a string. The problem with NOW() as you indicate is it includes current time. So to capture from the beginning of the query day (0 hour and minute) instead of: <= DATE_SUB(NOW(), INTERVAL 99 DAY)

I did (php):

$current_sql_date = date('Y-m-d 00:00:00');

in the sql:

$sql_x = " <= DATE_SUB('$current_sql_date', INTERVAL 99 DAY)"

With that, you will be retrieving data from midnight of the given day

Safest way to get last record ID from a table

One more way -

select * from <table> where  id=(select max(id) from <table>)

Also you can check on this link -

Rollback transaction after @Test

You need to run your test with a Spring context and a transaction manager, e.g.,

@ContextConfiguration(locations = {"/your-applicationContext.xml"})
public class StudentSystemTest {

     public void testTransactionalService() {
         // test transactional service

     public void testNonTransactionalService() {
         // test non-transactional service

See chapter 3.5.8. Transaction Management of the Spring reference for further details.

What is the simplest way to convert array to vector?

You're asking the wrong question here - instead of forcing everything into a vector ask how you can convert test to work with iterators instead of a specific container. You can provide an overload too in order to retain compatibility (and handle other containers at the same time for free):

void test(const std::vector<int>& in) {
  // Iterate over vector and do whatever


template <typename Iterator>
void test(Iterator begin, const Iterator end) {
    // Iterate over range and do whatever

template <typename Container>
void test(const Container& in) {
    test(std::begin(in), std::end(in));

Which lets you do:

int x[3]={1, 2, 3};
test(x); // Now correct

(Ideone demo)

Customize UITableView header section

- (void)tableView:(UITableView *)tableView willDisplayHeaderView:(UIView *)view forSection:(NSInteger)section
    if([view isKindOfClass:[UITableViewHeaderFooterView class]]){

        UITableViewHeaderFooterView *headerView = view;

        [[headerView textLabel] setTextColor:[UIColor colorWithHexString:@"666666"]];
        [[headerView textLabel] setFont:[UIFont fontWithName:@"fontname" size:10]];

If you want to change the font of the textLabel in your section header you want to do it in willDisplayHeaderView. To set the text you can do it in viewForHeaderInSection or titleForHeaderInSection. Good luck!

How do I get a UTC Timestamp in JavaScript?

I actually think Date values in js are far better than say the C# DateTime objects. The C# DateTime objects have a Kind property, but no strict underlying time zone as such, and time zone conversions are difficult to track if you are converting between two non UTC and non local times. In js, all Date values have an underlying UTC value which is passed around and known regardless of the offest or time zone conversions that you do. My biggest complaint about the Date object is the amount of undefined behaviour that browser implementers have chosen to include, which can confuse people who attack dates in js with trial and error than reading the spec. Using something like iso8601.js solves this varying behaviour by defining a single implementation of the Date object.

By default, the spec says you can create dates with an extended ISO 8601 date format like

var someDate = new Date('2010-12-12T12:00Z');

So you can infer the exact UTC time this way.

When you want to pass the Date value back to the server you would call


or if you would rather work with a millisecond timestamp (number of milliseconds from the 1st January 1970 UTC)


ISO 8601 is a standard. You can't be confused about what a date string means if you include the date offset. What this means for you as a developer is that you never have to deal with local time conversions yourself. The local time values exist purely for the benefit of the user, and date values by default display in their local time. All the local time manipulations allow you to display something sensible to the user and to convert strings from user input. It's good practice to convert to UTC as soon as you can, and the js Date object makes this fairly trivial.

On the downside there is not a lot of scope for forcing the time zone or locale for the client (that I am aware of), which can be annoying for website-specific settings, but I guess the reasoning behind this is that it's a user configuration that shouldn't be touched.

So, in short, the reason there isn't a lot of native support for time zone manipulation is because you simply don't want to be doing it.

BULK INSERT with identity (auto-increment) column

Add an id column to the csv file and leave it blank:

,name1,addr test 1
,name2,addr test 2

Remove KEEPIDENTITY keyword from query:

BULK INSERT Employee  FROM 'path\tempFile.csv ' 

The id identity field will be auto-incremented.

If you assign values to the id field in the csv, they'll be ignored unless you use the KEEPIDENTITY keyword, then they'll be used instead of auto-increment.

Select something that has more/less than x character

If your experiencing the same problem while querying a DB2 database, you'll need to use the below query.

cast(STATE as varchar(40)) 

Python Anaconda - How to Safely Uninstall

I always try to follow the developers advice, since they are usually the ones that now how it would affect your system. Theoretically this should be the safest way:

Install the Anaconda-Clean package from Anaconda Prompt (terminal on Linux or macOS):

conda install anaconda-clean

In the same window, run one of these commands:

  1. Remove all Anaconda-related files and directories with a confirmation prompt before deleting each one:


  1. Remove all Anaconda-related files and directories without being prompted to delete each one:

anaconda-clean --yes

Anaconda-Clean creates a backup of all files and directories that might be removed in a folder named .anaconda_backup in your home directory. Also note that Anaconda-Clean leaves your data files in the AnacondaProjects directory untouched.

Android Completely transparent Status Bar?

The following code will create a fully transparent status bar:

package com.demo;

import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;

public class MainActivity extends AppCompatActivity {

    protected void onCreate(Bundle savedInstanceState) {

        if (Build.VERSION.SDK_INT >= 19 && Build.VERSION.SDK_INT < 21) {
            setWindowFlag(this, WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS, true);
        if (Build.VERSION.SDK_INT >= 19) {
            getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
        if (Build.VERSION.SDK_INT >= 21) {
            setWindowFlag(this, WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS, false);

    public static void setWindowFlag(Activity activity, final int bits, boolean on) {
        Window win = activity.getWindow();
        WindowManager.LayoutParams winParams = win.getAttributes();
        if (on) {
            winParams.flags |= bits;
        } else {
            winParams.flags &= ~bits;

How do you add a timed delay to a C++ program?


void sleep(unsigned seconds);

sleep() suspends execution for an interval (seconds). With a call to sleep, the current program is suspended from execution for the number of seconds specified by the argument seconds. The interval is accurate only to the nearest hundredth of a second or to the accuracy of the operating system clock, whichever is less accurate.

Install opencv for Python 3.3

I can't comment on midopa's excellent answer due to lack of reputation.

On a Mac I (finally) successfully installed opencv from source using the following commands:

-D PYTHON_EXECUTABLE=/Library/Frameworks/Python.framework/Versions/3.4/bin/python3 
-D PYTHON_LIBRARY=/Library/Frameworks/Python.framework//Versions/3.4/lib/libpython3.4m.dylib 
-D PYTHON_INCLUDE_DIR=/Library/Frameworks/Python.framework/Versions/3.4/include/python3.4m 
-D PYTHON_NUMPY_INCLUDE_DIRS=/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/numpy/core/include/numpy 
-D PYTHON_PACKAGES_PATH=/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages 


make -j8

change 8 for the number of threads your machine can handle, to speed things up

sudo make install

I added a PYTHONPATH environment variable to my ~/.bash_profile file so that Python could find


[For those using PyCharm, I had to go to Preferences > Project Structure > Add Content Root, and added the path to's parent directory: /usr/local/lib/python3.4/site-packages]

This command got me past errors such as:

Could NOT find PythonLibs, by explicitly declaring the python library path

ld: can't link with a main executable for architecture x86_64
collect2: error: ld returned 1 exit status
make[2]: *** [lib/] Error 1
make[1]: *** [modules/python2/CMakeFiles/opencv_python2.dir/all] Error 2
make: *** [all] Error 2

by explicitly pointing to the libpython3.4m.dylib

In terminal, check that it worked with:

>>> import cv2

It's all good if you don't get ImportError: No module named 'cv2'

This worked on a Macbook Pro Retina 15" 2013, Mavericks 10.9.4, Python 3.4.1 (previously installed from official download), opencv3 from source. Hope that this helps someone.

JBoss default password

just commenting the line of user and password in file ./server/default/conf/props worked for me

How do I set up the database.yml file in Rails?

The database.yml is the file where you set up all the information to connect to the database. It differs depending on the kind of DB you use. You can find more information about this in the Rails Guide or any tutorial explaining how to setup a rails project.

The information in the database.yml file is scoped by environment, allowing you to get a different setting for testing, development or production. It is important that you keep those distinct if you don't want the data you use for development deleted by mistake while running your test suite.

Regarding source control, you should not commit this file but instead create a template file for other developers (called database.yml.template). When deploying, the convention is to create this database.yml file in /shared/config directly on the server.

With SVN: svn propset svn:ignore config "database.yml"

With Git: Add config/database.yml to the .gitignore file or with git-extra git ignore config/database.yml

... and now, some examples:


adapter: sqlite3
database: db/db_dev_db.sqlite3
pool: 5
timeout: 5000


adapter: mysql
database: my_db
username: root
socket: /tmp/mysql.sock
pool: 5
timeout: 5000

MongoDB with MongoID (called mongoid.yml, but basically the same thing)

host: <%= ENV['MONGOID_HOST'] %>
port: <%= ENV['MONGOID_PORT'] %>
username: <%= ENV['MONGOID_USERNAME'] %>
password: <%= ENV['MONGOID_PASSWORD'] %>
database: <%= ENV['MONGOID_DATABASE'] %>
# slaves:
#   - host: slave1.local
#     port: 27018
#   - host: slave2.local
#     port: 27019

Rounded Corners Image in Flutter

Use ClipRRect with set image property of fit: BoxFit.fill

          borderRadius: new BorderRadius.circular(10.0),
          child: Image(
            fit: BoxFit.fill,
            image: AssetImage('images/image.png'),
            width: 100.0,
            height: 100.0,

How to implement band-pass Butterworth filter with Scipy.signal.butter

The filter design method in accepted answer is correct, but it has a flaw. SciPy bandpass filters designed with b, a are unstable and may result in erroneous filters at higher filter orders.

Instead, use sos (second-order sections) output of filter design.

from scipy.signal import butter, sosfilt, sosfreqz

def butter_bandpass(lowcut, highcut, fs, order=5):
        nyq = 0.5 * fs
        low = lowcut / nyq
        high = highcut / nyq
        sos = butter(order, [low, high], analog=False, btype='band', output='sos')
        return sos

def butter_bandpass_filter(data, lowcut, highcut, fs, order=5):
        sos = butter_bandpass(lowcut, highcut, fs, order=order)
        y = sosfilt(sos, data)
        return y

Also, you can plot frequency response by changing

b, a = butter_bandpass(lowcut, highcut, fs, order=order)
w, h = freqz(b, a, worN=2000)


sos = butter_bandpass(lowcut, highcut, fs, order=order)
w, h = sosfreqz(sos, worN=2000)

Forward slash in Java Regex

Double escaping is required when presented as a string.

Whenever I'm making a new regular expression I do a bunch of tests with online tools, for example:

That website allows you to enter the regular expression, which it'll escape into a string for you, and you can then test it against different inputs.

JSON date to Java date?

If you need to support more than one format you will have to pattern match your input and parse accordingly.

final DateFormat fmt;
if (dateString.endsWith("Z")) {
    fmt = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
} else {
    fmt = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ");

I'd guess you're dealing with a bug in the API you're using which has quoted the Z timezone date pattern somewhere...

How can I get the session object if I have the entity-manager?

I was working in Wildfly but I was using

org.hibernate.Session session = ((org.hibernate.ejb.EntityManagerImpl) em.getDelegate()).getSession();

and the correct was

org.hibernate.Session session = (Session) manager.getDelegate();

How to call codeigniter controller function from view

One idea i can give is,

Call that function in controller itself and return value to view file. Like,

class Business extends CI_Controller {
    public function index() {
            $data['css'] = 'profile';

            $data['cur_url'] = $this->getCurrURL(); // the function called and store val
     function getCurrURL() {
            return $currURL;


in view(home_view.php) use that variable. Like,

echo $cur_url;

A hex viewer / editor plugin for Notepad++?

The hex editor plugin mentioned by ellak still works, but it seems that you need the TextFX Characters plugin as well.

I initially installed only the hex plugin and Notepad++ would no longer pop up; instead it started eating memory (killed it at 1.2 GB). I removed it again and for other reasons installed the TextFX plugin (based on Find multiple lines in Notepad++)

Out of curiosity I installed the hex plugin again and now it works.

Note that this is on a fresh install of Windows 7 64 bit.

php get values from json encode

json_decode() will return an object or array if second value it's true:

$json = '{"countryId":"84","productId":"1","status":"0","opId":"134"}';
$json = json_decode($json, true);
echo $json['countryId'];
echo $json['productId'];
echo $json['status'];
echo $json['opId'];

How to remove .html from URL?

To remove the .html extension from your urls, you can use the following code in root/htaccess :

RewriteEngine on

RewriteCond %{THE_REQUEST} /([^.]+)\.html [NC]
RewriteRule ^ /%1 [NC,L,R]

RewriteCond %{REQUEST_FILENAME}.html -f
RewriteRule ^ %{REQUEST_URI}.html [NC,L]

NOTE: If you want to remove any other extension, for example to remove the .php extension, just replace the html everywhere with php in the code above.

How to delete all files from a specific folder?

string[] filePaths = Directory.GetFiles(@"c:\MyDir\");
foreach (string filePath in filePaths)

Or in a single line:

Array.ForEach(Directory.GetFiles(@"c:\MyDir\"), File.Delete);

For div to extend full height

Did you remember setting the height of the html and body tags in your CSS? This is generally how I've gotten DIVs to extend to full height:

    <style type="text/css">

      html,body { height: 100%; margin: 0px; padding: 0px; }
      #full { background: #0f0; height: 100% }

    <div id="full">

In SQL Server, how do I generate a CREATE TABLE statement for a given table?

I've modified the version above to run for all tables and support new SQL 2005 data types. It also retains the primary key names. Works only on SQL 2005 (using cross apply).

select  'create table [' + + '] (' + o.list + ')' + CASE WHEN tc.Constraint_Name IS NULL THEN '' ELSE 'ALTER TABLE ' + so.Name + ' ADD CONSTRAINT ' + tc.Constraint_Name  + ' PRIMARY KEY ' + ' (' + LEFT(j.List, Len(j.List)-1) + ')' END
from    sysobjects so
cross apply
        '  ['+column_name+'] ' + 
        data_type + case data_type
            when 'sql_variant' then ''
            when 'text' then ''
            when 'ntext' then ''
            when 'xml' then ''
            when 'decimal' then '(' + cast(numeric_precision as varchar) + ', ' + cast(numeric_scale as varchar) + ')'
            else coalesce('('+case when character_maximum_length = -1 then 'MAX' else cast(character_maximum_length as varchar) end +')','') end + ' ' +
        case when exists ( 
        select id from syscolumns
        where object_name(id)
        and name=column_name
        and columnproperty(id,name,'IsIdentity') = 1 
        ) then
        'IDENTITY(' + 
        cast(ident_seed( as varchar) + ',' + 
        cast(ident_incr( as varchar) + ')'
        else ''
        end + ' ' +
         (case when UPPER(IS_NULLABLE) = 'NO' then 'NOT ' else '' end ) + 'NULL ' + 
          case when information_schema.columns.COLUMN_DEFAULT IS NOT NULL THEN 'DEFAULT '+ information_schema.columns.COLUMN_DEFAULT ELSE '' END + ', ' 

     from information_schema.columns where table_name =
     order by ordinal_position
    FOR XML PATH('')) o (list)
left join
    information_schema.table_constraints tc
on  tc.Table_name       = so.Name
AND tc.Constraint_Type  = 'PRIMARY KEY'
cross apply
    (select '[' + Column_Name + '], '
     FROM   information_schema.key_column_usage kcu
     WHERE  kcu.Constraint_Name = tc.Constraint_Name
     FOR XML PATH('')) j (list)
where   xtype = 'U'
AND name    NOT IN ('dtproperties')

Update: Added handling of the XML data type

Update 2: Fixed cases when 1) there is multiple tables with the same name but with different schemas, 2) there is multiple tables having PK constraint with the same name

LINQ to Entities how to update a record

In most cases @tster's answer will suffice. However, I had a scenario where I wanted to update a row without first retrieving it.

My situation is this: I've got a table where I want to "lock" a row so that only a single user at a time will be able to edit it in my app. I'm achieving this by saying

update items set status = 'in use', lastuser = @lastuser, lastupdate = @updatetime where ID = @rowtolock and @status = 'free'

The reason being, if I were to simply retrieve the row by ID, change the properties and then save, I could end up with two people accessing the same row simultaneously. This way, I simply send and update claiming this row as mine, then I try to retrieve the row which has the same properties I just updated with. If that row exists, great. If, for some reason it doesn't (someone else's "lock" command got there first), I simply return FALSE from my method.

I do this by using context.Database.ExecuteSqlCommand which accepts a string command and an array of parameters.

Just wanted to add this answer to point out that there will be scenarios in which retrieving a row, updating it, and saving it back to the DB won't suffice and that there are ways of running a straight update statement when necessary.

Node JS Error: ENOENT

"/tmp/test.jpg" is not the correct path – this path starts with / which is the root directory.

In unix, the shortcut to the current directory is .

Try this "./tmp/test.jpg"

Increment a value in Postgres

UPDATE totals 
   SET total = total + 1
WHERE name = 'bill';

If you want to make sure the current value is indeed 203 (and not accidently increase it again) you can also add another condition:

UPDATE totals 
   SET total = total + 1
WHERE name = 'bill'
  AND total = 203;

bash: mkvirtualenv: command not found

Solved my issue in Ubuntu 14.04 OS with python 2.7.6, by adding below two lines into ~/.bash_profile (or ~/.bashrc in unix) files.

source "/usr/local/bin/"

export WORKON_HOME="/opt/virtual_env/"

And then executing both these lines onto the terminal.

Using multiple case statements in select query

There are two ways to write case statements, you seem to be using a combination of the two

case a.updatedDate
    when 1760 then 'Entered on' + a.updatedDate
    when 1710 then 'Viewed on' + a.updatedDate
    else 'Last Updated on' + a.updateDate


    when a.updatedDate = 1760 then 'Entered on' + a.updatedDate
    when a.updatedDate = 1710 then 'Viewed on' + a.updatedDate
    else 'Last Updated on' + a.updateDate

are equivalent. They may not work because you may need to convert date types to varchars to append them to other varchars.

How can I get the height of an element using css only

You could use the CSS calc parameter to calculate the height dynamically like so:

.dynamic-height {_x000D_
   color: #000;_x000D_
   font-size: 12px;_x000D_
   margin-top: calc(100% - 10px);_x000D_
   text-align: left;_x000D_
<div class='dynamic-height'>_x000D_
    <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem.</p>_x000D_

LINQ select in C# dictionary

var res = exitDictionary
            .Select(p => p.Value).Cast<Dictionary<string, object>>()
            .SelectMany(d => d)
            .Where(p => p.Key == "fieldname1")
            .Select(p => p.Value).Cast<List<Dictionary<string,string>>>()
            .SelectMany(l => l)
            .SelectMany(d=> d)
            .Where(p => p.Key == "valueTitle")
            .Select(p => p.Value)

This also works, and easy to understand.

Python interpreter error, x takes no arguments (1 given)

Make sure, that all of your class methods (updateVelocity, updatePosition, ...) take at least one positional argument, which is canonically named self and refers to the current instance of the class.

When you call particle.updateVelocity(), the called method implicitly gets an argument: the instance, here particle as first parameter.

ReferenceError: document is not defined (in plain JavaScript)

It depends on when the self executing anonymous function is running. It is possible that it is running before window.document is defined.

In that case, try adding a listener

window.addEventListener('load', yourFunction, false);
// ..... or 
window.addEventListener('DOMContentLoaded', yourFunction, false);

yourFunction () {
  // some ocde


Update: (after the update of the question and inclusion of the code)

Read the following about the issues in referencing DOM elements from a JavaScript inserted and run in head element:
- “getElementsByTagName(…)[0]” is undefined?
- Traversing the DOM

Sending emails with Javascript

The way I'm doing it now is basically like this:


<textarea id="myText">
    Lorem ipsum...
<button onclick="sendMail(); return false">Send</button>

The Javascript:

function sendMail() {
    var link = "mailto:[email protected]"
             + "[email protected]"
             + "&subject=" + encodeURIComponent("This is my subject")
             + "&body=" + encodeURIComponent(document.getElementById('myText').value)
    window.location.href = link;

This, surprisingly, works rather well. The only problem is that if the body is particularly long (somewhere over 2000 characters), then it just opens a new email but there's no information in it. I suspect that it'd be to do with the maximum length of the URL being exceeded.

Reading value from console, interactively

Easiest way is to use readline-sync

It process one by one input and out put.

npm i readline-sync


var firstPrompt = readlineSync.question('Are you sure want to initialize new db? This will drop whole database and create new one, Enter: (yes/no) ');

if (firstPrompt === 'yes') {
    console.log('--firstPrompt--', firstPrompt)
} else if (firstPrompt === 'no') {
    var secondPrompt = readlineSync.question('Do you want to modify migration?, Enter: (yes/no) ');
    console.log('secondPrompt ', secondPrompt)
} else {
    console.log('Invalid Input')

How to obtain the total numbers of rows from a CSV file in Python?

You need to count the number of rows:

row_count = sum(1 for row in fileObject)  # fileObject is your csv.reader

Using sum() with a generator expression makes for an efficient counter, avoiding storing the whole file in memory.

If you already read 2 rows to start with, then you need to add those 2 rows to your total; rows that have already been read are not being counted.

Split array into two parts without for loop in java

You can use System.arraycopy().

int[] source = new int[1000];

int[] part1 = new int[500];
int[] part2 = new int[500];

//              (src   , src-offset  , dest , offset, count)
System.arraycopy(source, 0           , part1, 0     , part1.length);
System.arraycopy(source, part1.length, part2, 0     , part2.length);

How to deserialize a JObject to .NET object

Too late, just in case some one is looking for another way:

void Main()
    string jsonString = @"{
  'Stores': [
    'Lambton Quay',
    'Willis Street'
  'Manufacturers': [
      'Name': 'Acme Co',
      'Products': [
          'Name': 'Anvil',
          'Price': 50
      'Name': 'Contoso',
      'Products': [
          'Name': 'Elbow Grease',
          'Price': 99.95
          'Name': 'Headlight Fluid',
          'Price': 4

    Product product = new Product();
    //Serializing to Object
    Product obj = JObject.Parse(jsonString).SelectToken("$.Manufacturers[?(@.Name == 'Acme Co' && @.Name != 'Contoso')]").ToObject<Product>();


public class Product
    public string Name { get; set; }
    public decimal Price { get; set; }

Is there any free OCR library for Android?

Google Goggles is the perfect application for doing both OCR and translation.
And the good news is that Google Goggles to Become App Platform.

Until then, you can use IQ Engines.

Versioning SQL Server database

First, you must choose the version control system that is right for you:

  • Centralized Version Control system - a standard system where users check out/check in before/after they work on files, and the files are being kept in a single central server

  • Distributed Version Control system - a system where the repository is being cloned, and each clone is actually the full backup of the repository, so if any server crashes, then any cloned repository can be used to restore it After choosing the right system for your needs, you'll need to setup the repository which is the core of every version control system All this is explained in the following article:

After setting up a repository, and in case of a central version control system a working folder, you can read this article. It shows how to setup source control in a development environment using:

  • SQL Server Management Studio via the MSSCCI provider,

  • Visual Studio and SQL Server Data Tools

  • A 3rd party tool ApexSQL Source Control

Unzip All Files In A Directory

The following bash script extracts all zip files in the current directory into new dirs with the filename of the zip file, i.e.:

The following files: 

Will be extracted to:


Shell script:

for zip in *.zip
  dirname=`echo $zip | sed 's/\.zip$//'`
  if mkdir "$dirname"
    if cd "$dirname"
      unzip ../"$zip"
      cd ..
      # rm -f $zip # Uncomment to delete the original zip file
      echo "Could not unpack $zip - cd failed"
    echo "Could not unpack $zip - mkdir failed"

MySQL, create a simple function

MySQL function example:

Open the mysql terminal:

el@apollo:~$ mysql -u root -pthepassword yourdb

Drop the function if it already exists

mysql> drop function if exists myfunc;
Query OK, 0 rows affected, 1 warning (0.00 sec)

Create the function

mysql> create function hello(id INT)
    -> returns CHAR(50)
    -> return 'foobar';
Query OK, 0 rows affected (0.01 sec)

Create a simple table to test it out with

mysql> create table yar (id INT);
Query OK, 0 rows affected (0.07 sec)

Insert three values into the table yar

mysql> insert into yar values(5), (7), (9);
Query OK, 3 rows affected (0.04 sec)
Records: 3  Duplicates: 0  Warnings: 0

Select all the values from yar, run our function hello each time:

mysql> select id, hello(5) from yar;
| id   | hello(5) |
|    5 | foobar   |
|    7 | foobar   |
|    9 | foobar   |
3 rows in set (0.01 sec)

Verbalize and internalize what just happened:

You created a function called hello which takes one parameter. The parameter is ignored and returns a CHAR(50) containing the value 'foobar'. You created a table called yar and added three rows to it. The select statement runs the function hello(5) for each row returned by yar.

Mongoose query where value is not null

total count the documents where the value of the field is not equal to the specified value.

async function getRegisterUser() {
    return Login.count({"role": { $ne: 'Super Admin' }}, (err, totResUser) => {
        if (err) {
            return err;
        return totResUser;

Custom seekbar (thumb size, color and background)

  • First at all, use android:splitTrack="false" for the transparency problem of your thumb.

  • For the seekbar.png, you have to use a 9 patch. It would be good for the rounded border and the shadow of your image.

What is the path that Django uses for locating and loading templates?

If using Django settings as installed, then why not just use its baked-in, predefined BASE_DIR and TEMPLATES? In the pip installed Django(v1.8), I get:

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__))) 

        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [
            BASE_DIR + '/templates/',
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [

Jenkins could not run git

Also you can set Git location in Jenkins server/node configuration:

goto Configure, under section Node Properties mark checkbox Tools Location and set yours path to Git.

enter image description here

HttpContext.Current.Session is null when routing requests

What @Bogdan Maxim said. Or change to use InProc if you're not using an external sesssion state server.

<sessionState mode="InProc" timeout="20" cookieless="AutoDetect" />

Look here for more info on the SessionState directive.

regular expression to match exactly 5 digits

My test string for the following:


If I understand your question, you'd want ["12345", "54321", "15234", "52341"].

If JS engines supported regexp lookbehinds, you could do:


Since it doesn't currently, you could:


and remove the leading non-digit from appropriate results, or:

result = [];
while (( match = pentadigit.exec(testing) )) {

Note that for IE, it seems you need to use a RegExp stored in a variable rather than a literal regexp in the while loop, otherwise you'll get an infinite loop.

Running Python from Atom

Follow the steps:

  1. Install Python
  2. Install Atom
  3. Install and configure Atom package for Python
  4. Install and configure Python Linter
  5. Install Script Package in Atom
  6. Download and install Syntax Highlighter for Python
  7. Install Version control package Run Python file

More details for each step Click Here

How to detect iPhone 5 (widescreen devices)?

Here is the correct test of the device, without depending on the orientation

- (BOOL)isIPhone5
    CGSize size = [[UIScreen mainScreen] bounds].size;
    if (MIN(size.width,size.height) == 320 && MAX(size.width,size.height == 568)) {
        return YES;
    return NO;

Spring MVC + JSON = 406 Not Acceptable

With Spring 4 you only add @EnableWebMvc, for example:

@RequestMapping(value = "/articles/action", headers="Accept=*/*",  produces="application/json")
public class ArticlesController {


symfony2 : failed to write cache directory

You probably aborted a clearcache halfway and now you already have an app/cache/dev_old.

Try this (in the root of your project, assuming you're on a Unixy environment like OS X or Linux):

rm -rf app/cache/dev*

ActionBarActivity is deprecated

android developers documentation says : "Updated the AppCompatActivity as the base class for activities that use the support library action bar features. This class replaces the deprecated ActionBarActivity."

checkout changes for Android Support Library, revision 22.1.0 (April 2015)

SQL Query Multiple Columns Using Distinct on One Column Only

select * from tblFruit where
tblFruit_ID in (Select max(tblFruit_ID) FROM tblFruit group by tblFruit_FruitType)

How to Automatically Start a Download in PHP?

my code works for txt,doc,docx,pdf,ppt,pptx,jpg,png,zip extensions and I think its better to use the actual MIME types explicitly.

$file_name = "a.txt";

// extracting the extension:
$ext = substr($file_name, strpos($file_name,'.')+1);

header('Content-disposition: attachment; filename='.$file_name);

if(strtolower($ext) == "txt")
    header('Content-type: text/plain'); // works for txt only
    header('Content-type: application/'.$ext); // works for all extensions except txt

jQuery Ajax error handling, show custom exception messages

Make sure you're setting Response.StatusCode to something other than 200. Write your exception's message using Response.Write, then use...

xhr.responseText your javascript.

SQL Server - Convert varchar to another collation (code page) to fix character encoding

We may need more information. Here is what I did to reproduce on SQL Server 2008:

    NAME = N'Test'
    , FILENAME = N'...Test.mdf' 
    , SIZE = 3072KB 
    , FILEGROWTH = 1024KB 
    LOG ON 
    NAME = N'Test_log'
    , FILENAME = N'...Test_log.ldf' 
    , SIZE = 1024KB 
    , FILEGROWTH = 10%
    COLLATE SQL_Latin1_General_CP850_BIN2
CREATE TABLE [dbo].[MyTable]
    [SomeCol] [varchar](50) NULL
    ) ON [PRIMARY]
Insert MyTable( SomeCol )
Select '±' Collate SQL_Latin1_General_CP1_CI_AS
Select SomeCol, SomeCol Collate SQL_Latin1_General_CP1_CI_AS
From MyTable

Results show the original character. Declaring collation in the query should return the proper character from SQL Server's perspective however it may be the case that the presentation layer is then converting to something yet different like UTF-8.

How to convert HTML file to word?

When doing this I found it easiest to:

  1. Visit the page in a web browser
  2. Save the page using the web browser with .htm extension (and maybe a folder with support files)
  3. Start Word and open the saved htmfile (Word will open it correctly)
  4. Make any edits if needed
  5. Select Save As and then choose the extension you would like doc, docx, etc.

Array to Hash Ruby

Ruby 2.1.0 introduced a to_h method on Array that does what you require if your original array consists of arrays of key-value pairs:

[[:foo, :bar], [1, 2]].to_h
# => {:foo => :bar, 1 => 2}

org.hibernate.exception.SQLGrammarException: could not insert [com.sample.Person]


  1. Its not necessary to specify table name in Person.hbm.xml (........) when you are creating table with same as class name. Also applicable to fields.

  2. While creating "person" table in your respective database,make sure that whatever FILEDS names you specified in Person.hbm.xml must match with table COLUMNS names ELSE you wil get above error.

With ' N ' no of nodes, how many different Binary and Binary Search Trees possible?

I recommend this article by my colleague Nick Parlante (from back when he was still at Stanford). The count of structurally different binary trees (problem 12) has a simple recursive solution (which in closed form ends up being the Catalan formula which @codeka's answer already mentioned).

I'm not sure how the number of structurally different binary search trees (BSTs for short) would differ from that of "plain" binary trees -- except that, if by "consider tree node values" you mean that each node may be e.g. any number compatible with the BST condition, then the number of different (but not all structurally different!-) BSTs is infinite. I doubt you mean that, so, please clarify what you do mean with an example!

Using multiple delimiters in awk

If your whitespace is consistent you could use that as a delimiter, also instead of inserting \t directly, you could set the output separator and it will be included automatically:

< file awk -v OFS='\t' -v FS='[/ ]' '{print $3, $5, $NF}'

PHP refresh window? equivalent to F5 page reload?

echo "<script>window.opener.location.reload();</script>";
echo "<script>window.close();</script>";

Get Table and Index storage size in sql server

with pages as (
    SELECT object_id, SUM (reserved_page_count) as reserved_pages, SUM (used_page_count) as used_pages,
            SUM (case 
                    when (index_id < 2) then (in_row_data_page_count + lob_used_page_count + row_overflow_used_page_count)
                    else lob_used_page_count + row_overflow_used_page_count
                 end) as pages
    FROM sys.dm_db_partition_stats
    group by object_id
), extra as (
    SELECT p.object_id, sum(reserved_page_count) as reserved_pages, sum(used_page_count) as used_pages
    FROM sys.dm_db_partition_stats p, sys.internal_tables it
    WHERE it.internal_type IN (202,204,211,212,213,214,215,216) AND p.object_id = it.object_id
    group by p.object_id
SELECT object_schema_name(p.object_id) + '.' + object_name(p.object_id) as TableName, (p.reserved_pages + isnull(e.reserved_pages, 0)) * 8 as reserved_kb,
        pages * 8 as data_kb,
        (CASE WHEN p.used_pages + isnull(e.used_pages, 0) > pages THEN (p.used_pages + isnull(e.used_pages, 0) - pages) ELSE 0 END) * 8 as index_kb,
        (CASE WHEN p.reserved_pages + isnull(e.reserved_pages, 0) > p.used_pages + isnull(e.used_pages, 0) THEN (p.reserved_pages + isnull(e.reserved_pages, 0) - p.used_pages + isnull(e.used_pages, 0)) else 0 end) * 8 as unused_kb
from pages p
left outer join extra e on p.object_id = e.object_id

Takes into account internal tables, such as those used for XML storage.

Edit: If you divide the data_kb and index_kb values by 1024.0, you will get the numbers you see in the GUI.

Passing variables through handlebars partial

Sounds like you want to do something like this:

{{> person {another: 'attribute'} }}

Yehuda already gave you a way of doing that:

{{> person this}}

But to clarify:

To give your partial its own data, just give it its own model inside the existing model, like so:

{{> person this.childContext}}

In other words, if this is the model you're giving to your template:

var model = {
    some : 'attribute'

Then add a new object to be given to the partial:

var model = {
    some : 'attribute',
    childContext : {
        'another' : 'attribute' // this goes to the child partial

childContext becomes the context of the partial like Yehuda said -- in that, it only sees the field another, but it doesn't see (or care about the field some). If you had id in the top level model, and repeat id again in the childContext, that'll work just fine as the partial only sees what's inside childContext.

How to execute shell command in Javascript

Here is simple command that executes ifconfig shell command of Linux

var process = require('child_process');
process.exec('ifconfig',function (err,stdout,stderr) {
    if (err) {
    } else {

Referring to a table in LaTeX

You must place the label after a caption in order to for label to store the table's number, not the chapter's number.

\begin{tabular}{| p{5cm} | p{5cm} | p{5cm} |}
  -- cut --
\caption{My table}

Table \ref{table:kysymys} on page \pageref{table:kysymys} refers to the ...

How to use ADB to send touch events to device using sendevent command?

Android comes with an input command-line tool that can simulate miscellaneous input events. To simulate tapping, it's:

input tap x y

You can use the adb shell ( > 2.3.5) to run the command remotely:

adb shell input tap x y

Intermediate language used in scalac?

The nearest equivalents would be icode and bcode as used by scalac, view Miguel Garcia's site on the Scalac optimiser for more information, here:

You might also consider Java bytecode itself to be your intermediate representation, given that bytecode is the ultimate output of scalac.

Or perhaps the true intermediate is something that the JIT produces before it finally outputs native instructions?

Ultimately though... There's no single place that you can point at an claim "there's the intermediate!". Scalac works in phases that successively change the abstract syntax tree, every single phase produces a new intermediate. The whole thing is like an onion, and it's very hard to try and pick out one layer as somehow being more significant than any other.

Changing font size and direction of axes text in ggplot2

Using "fill" attribute helps in cases like this. You can remove the text from axis using element_blank()and show multi color bar chart with a legend. I am plotting a part removal frequency in a repair shop as below

ggplot(data=df_subset,aes(x=Part,y=Removal_Frequency,fill=Part))+geom_bar(stat="identity")+theme(axis.text.x  = element_blank())

I went for this solution in my case as I had many bars in bar chart and I was not able to find a suitable font size which is both readable and also small enough not to overlap each other.

Why when a constructor is annotated with @JsonCreator, its arguments must be annotated with @JsonProperty?

It is possible to avoid constructor annotations with jdk8 where optionally the compiler will introduce metadata with the names of the constructor parameters. Then with jackson-module-parameter-names module Jackson can use this constructor. You can see an example at post Jackson without annotations

Should I use != or <> for not equal in T-SQL?

You can use whichever you like in T-SQL. The documentation says they both function the same way. I prefer !=, because it reads "not equal" to my (C/C++/C# based) mind, but database gurus seem to prefer <>.

How to disable/enable select field using jQuery?

Just simply use:

var update_pizza = function () {
     $("#pizza_kind").prop("disabled", !$('#pizza').prop('checked'));



div with dynamic min-height based on browser window height

Just look for my solution on jsfiddle, it is based on csslayout

body {_x000D_
  margin: 0;_x000D_
  padding: 0;_x000D_
  height: 100%; /* needed for container min-height */_x000D_
div#container {_x000D_
  position: relative; /* needed for footer positioning*/_x000D_
  height: auto !important; /* real browsers */_x000D_
  min-height: 100%; /* real browsers */_x000D_
div#header {_x000D_
  padding: 1em;_x000D_
  background: #efe;_x000D_
div#content {_x000D_
  /* padding:1em 1em 5em; *//* bottom padding for footer */_x000D_
div#footer {_x000D_
  position: absolute;_x000D_
  width: 100%;_x000D_
  bottom: 0; /* stick to bottom */_x000D_
  background: #ddd;_x000D_
<div id="container">_x000D_
  <div id="header">header</div>_x000D_
  <div id="content">_x000D_
  <div id="footer">_x000D_

Using "If cell contains" in VBA excel

Dim celltxt As String
celltxt = Selection.Text
If InStr(1, celltext, "TOTAL") > 0 Then
Selection.Value = "-"
End If

You declared "celltxt" and used "celltext" in the instr.

Why do we use $rootScope.$broadcast in AngularJS?

$rootScope basically functions as an event listener and dispatcher.

To answer the question of how it is used, it used in conjunction with rootScope.$on;


$rootScope.$on("hi", function(){
    //do something

However, it is a bad practice to use $rootScope as your own app's general event service, since you will quickly end up in a situation where every app depends on $rootScope, and you do not know what components are listening to what events.

The best practice is to create a service for each custom event you want to listen to or broadcast.

.service("hiEventService",function($rootScope) {
    this.broadcast = function() {$rootScope.$broadcast("hi")}
    this.listen = function(callback) {$rootScope.$on("hi",callback)}

Force LF eol in git repo and working copy

To force LF line endings for all text files, you can create .gitattributes file in top-level of your repository with the following lines (change as desired):

# Ensure all C and PHP files use LF.
*.c         eol=lf
*.php       eol=lf

which ensures that all files that Git considers to be text files have normalized (LF) line endings in the repository (normally core.eol configuration controls which one do you have by default).

Based on the new attribute settings, any text files containing CRLFs should be normalized by Git. If this won't happen automatically, you can refresh a repository manually after changing line endings, so you can re-scan and commit the working directory by the following steps (given clean working directory):

$ echo "* text=auto" >> .gitattributes
$ rm .git/index     # Remove the index to force Git to
$ git reset         # re-scan the working directory
$ git status        # Show files that will be normalized
$ git add -u
$ git add .gitattributes
$ git commit -m "Introduce end-of-line normalization"

or as per GitHub docs:

git add . -u
git commit -m "Saving files before refreshing line endings"
git rm --cached -r . # Remove every file from Git's index.
git reset --hard # Rewrite the Git index to pick up all the new line endings.
git add . # Add all your changed files back, and prepare them for a commit.
git commit -m "Normalize all the line endings" # Commit the changes to your repository.

See also: @Charles Bailey post.

In addition, if you would like to exclude any files to not being treated as a text, unset their text attribute, e.g.

manual.pdf      -text

Or mark it explicitly as binary:

# Denote all files that are truly binary and should not be modified.
*.png binary
*.jpg binary

To see some more advanced git normalization file, check .gitattributes at Drupal core:

# Drupal git normalization
# @see
# @see

# Normally these settings would be done with macro attributes for improved
# readability and easier maintenance. However macros can only be defined at the
# repository root directory. Drupal avoids making any assumptions about where it
# is installed.

# Define text file attributes.
# - Treat them as text.
# - Ensure no CRLF line-endings, neither on checkout nor on checkin.
# - Detect whitespace errors.
#   - Exposed by default in `git diff --color` on the CLI.
#   - Validate with `git diff --check`.
#   - Deny applying with `git apply --whitespace=error-all`.
#   - Fix automatically with `git apply --whitespace=fix`.

*.config  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.css     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.dist    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.engine  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.html    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=html
*.inc     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.install text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.js      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.json    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.lock    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.map     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.md      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.module  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.php     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.po      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.profile text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.script  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.sh      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.sql     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.svg     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.theme   text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.twig    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.txt     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.xml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.yml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2

# Define binary file attributes.
# - Do not treat them as text.
# - Include binary diff in patches instead of "binary files differ."
*.eot     -text diff
*.exe     -text diff
*.gif     -text diff
*.gz      -text diff
*.ico     -text diff
*.jpeg    -text diff
*.jpg     -text diff
*.otf     -text diff
*.phar    -text diff
*.png     -text diff
*.svgz    -text diff
*.ttf     -text diff
*.woff    -text diff
*.woff2   -text diff

See also:

Java: Get last element after split

With Guava:

final Splitter splitter = Splitter.on("-").trimResults();
assertEquals("Günnewig Uebachs", Iterables.getLast(splitter.split(one)));
assertEquals("Madison", Iterables.getLast(splitter.split(two)));

Splitter, Iterables

How do I deal with corrupted Git object files?

You can use "find" for remove all files in the /objects directory with 0 in size with the command:

find .git/objects/ -size 0 -delete

Backup is recommended.

Handling a timeout error in python sockets

Here is a solution I use in one of my project.


import socket
from timeit import default_timer as timer

def telnet(hostname, port=23, timeout=1):
    start = timer()
    connection = socket.socket()
        connection.connect((hostname, port))
        end = timer()
        delta = end - start
    except (socket.timeout, socket.gaierror) as error:
        logger.debug('telnet error: ', error)
        delta = None

    return {
        hostname: delta


def test_telnet_is_null_when_host_unreachable(self):
    hostname = 'unreachable'

    response = network_utils.telnet(hostname)

    self.assertDictEqual(response, {'unreachable': None})

def test_telnet_give_time_when_reachable(self):
    hostname = ''

    response = network_utils.telnet(hostname, port=22)

    self.assertGreater(response[hostname], 0)

Changing iframe src with Javascript

Here's the jQuery way to do it:

$('#calendar').attr('src', loc);

How to find cube root using Python?

def cube(x):
    if 0<=x: return x**(1./3.)
    return -(-x)**(1./3.)
print (cube(8))
print (cube(-8))

Here is the full answer for both negative and positive numbers.


Or here is a one-liner;

root_cube = lambda x: x**(1./3.) if 0<=x else -(-x)**(1./3.)

What Scala web-frameworks are available?

Note: Spiffy is outdated.



  • is written in Scala
  • uses the fantastic Akka library and actors to scale
  • uses servlet API 3.0 for asynchronous request handling
  • is modular (replacing components is straight forward)
  • uses DSLs to cut down on code where you don't want it
  • supports Scalate and Freemarker for templating

Spiffy is a web framework using Scala, Akka (a Scala actor implementation), and the Java Servlet 3.0 API. It makes use of the the async interface and aims to provide a massively parallel and scalable environment for web applications. Spiffy's various components are all based on the idea that they need to be independent minimalistic modules that do small amounts of work very quickly and hand off the request to the next component in the pipeline. After the last component is done processing the request it signals the servlet container by "completing" the request and sending it back to the client.


Calculate a MD5 hash from a string

I'd like to offer an alternative that appears to perform at least 10% faster than craigdfrench's answer in my tests (.NET 4.7.2):

public static string GetMD5Hash(string text)
    using ( var md5 = MD5.Create() )
        byte[] computedHash = md5.ComputeHash( Encoding.UTF8.GetBytes(text) );
        return new System.Runtime.Remoting.Metadata.W3cXsd2001.SoapHexBinary(computedHash).ToString();

If you prefer to have using System.Runtime.Remoting.Metadata.W3cXsd2001; at the top, the method body can be made an easier to read one-liner:

using ( var md5 = MD5.Create() )
    return new SoapHexBinary( md5.ComputeHash( Encoding.UTF8.GetBytes(text) ) ).ToString();

Obvious enough, but for completeness, in OP's context it would be used as:

sSourceData = "MySourceData";
tmpHash = GetMD5Hash(sSourceData);

Http 415 Unsupported Media type error with JSON

I was sending "delete" rest request and it failed with 415. I saw what content-type my server uses to hit the api. In my case, It was "application/json" instead of "application/json; charset=utf8".

So ask from your api developer And in the meantime try sending request with content-type= "application/json" only.

iPhone app signing: A valid signing identity matching this profile could not be found in your keychain

A good way to ensure that this happens cleanly is to clean your login keychain completely first.

Also, a really important step is to unlock your keychain before you import the private key and public key

 security unlock-keychain -p password ~/Library/Keychains/login.keychain 

Import private key into login keychain :

security import PrivateKey.p12 -k ~/Library/Keychains/login.keychain 

1 identity imported.

Import public key into login keychain :

security import PublicKeyName.pem -k ~/Library/Keychains/login.keychain 

1 key imported.

How to use subprocess popen Python

It may not be obvious how to break a shell command into a sequence of arguments, especially in complex cases. shlex.split() can do the correct tokenization for args (I'm using Blender's example of the call):

import shlex
from subprocess import Popen, PIPE
command = shlex.split('swfdump /tmp/filename.swf/ -d')
process = Popen(command, stdout=PIPE, stderr=PIPE)
stdout, stderr = process.communicate()

How to round down to nearest integer in MySQL?

Use FLOOR(), if you want to round your decimal to the lower integer. Examples:

FLOOR(1.9) => 1
FLOOR(1.1) => 1

Use ROUND(), if you want to round your decimal to the nearest integer. Examples:

ROUND(1.9) => 2
ROUND(1.1) => 1

Use CEIL(), if you want to round your decimal to the upper integer. Examples:

CEIL(1.9) => 2
CEIL(1.1) => 2

Append to the end of a Char array in C++

If your arrays are character arrays(which seems to be the case), You need a strcat().
Your destination array should have enough space to accommodate the appended data though.

In C++, You are much better off using std::string and then you can use std::string::append()

JavaFX - create custom button with image

A combination of previous 2 answers did the trick. Thanks. A new class which inherits from Button. Note: updateImages() should be called before showing the button.

import javafx.event.EventHandler;
import javafx.scene.control.Button;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseEvent;

public class ImageButton extends Button {

    public void updateImages(final Image selected, final Image unselected) {
        final ImageView iv = new ImageView(selected);

        iv.setOnMousePressed(new EventHandler<MouseEvent>() {
            public void handle(MouseEvent evt) {
        iv.setOnMouseReleased(new EventHandler<MouseEvent>() {
            public void handle(MouseEvent evt) {


How to resolve 'unrecognized selector sent to instance'?

Mine was something simple/stupid. Newbie mistake, for anyone that has converted their NSManagedObject to a normal NSObject.

I had:

@dynamic order_id;

when i should have had:

@synthesize order_id;

Delete a row in DataGridView Control in VB.NET

If dgv(11, dgv.CurrentRow.Index).Selected = True Then
    Exit Sub
End If

C++ auto keyword. Why is it magic?

The auto keyword specifies that the type of the variable that is being declared will be automatically deducted from its initializer. In case of functions, if their return type is auto then that will be evaluated by return type expression at runtime.

It can be very useful when we have to use the iterator. For e.g. for below code we can simply use the "auto" instead of writing the whole iterator syntax .

int main() 

// Initialize set 
set<int> s; 


// iterator pointing to 
// position where 2 is 
auto pos = s.find(3); 

// prints the set elements 
cout << "The set elements after 3 are: "; 
for (auto it = pos; it != s.end(); it++) 
    cout << *it << " "; 

return 0; 

This is how we can use "auto" keyword

How to increase MaximumErrorCount in SQL Server 2008 Jobs or Packages?

If I have open a package in BIDS ("Business Intelligence Development Studio", the tool you use to design the packages), and do not select any item in it, I have a "Properties" pane in the bottom right containing - among others, the MaximumErrorCount property. If you do not see it, maybe it is minimized and you have to open it (have a look at tabs in the right).

If you cannot find it this way, try the menu: View/Properties Window.

Or try the F4 key.

Format numbers in JavaScript similar to C#

You can do it in the following way: So you will not only format the number but you can also pass as a parameter how many decimal digits to display, you set a custom decimal and mile separator.

function format(number, decimals = 2, decimalSeparator = '.', thousandsSeparator = ',') {
    const roundedNumber = number.toFixed(decimals);
    let integerPart = '', fractionalPart = '';
    if (decimals == 0) {
        integerPart = roundedNumber;
        decimalSeparator = '';
    } else {
        let numberParts = roundedNumber.split('.');
        integerPart = numberParts[0];
        fractionalPart = numberParts[1];
    integerPart = integerPart.replace(/(\d)(?=(\d{3})+(?!\d))/g, `$1${thousandsSeparator}`);
    return `${integerPart}${decimalSeparator}${fractionalPart}`;


let min = 1556454.0001;
let max = 15556982.9999;
console.time('number format');
for (let i = 0; i < 15000; i++) {
    let randomNumber = Math.random() * (max - min) + min;

    let formated = format(randomNumber, 4, ',', '.'); // formated number

    console.debug('number: ', randomNumber, 'formated: ', formated);
console.timeEnd('number format');

Calculate distance between 2 GPS coordinates

This is very easy to do with geography type in SQL Server 2008.

SELECT geography::Point(lat1, lon1, 4326).STDistance(geography::Point(lat2, lon2, 4326))
-- computes distance in meters using eliptical model, accurate to the mm

4326 is SRID for WGS84 elipsoidal Earth model

SecurityException during executing jnlp file (Missing required Permissions manifest attribute in main jar)

JAR File Manifest Attributes for Security

The JAR file manifest contains information about the contents of the JAR file, including security and configuration information.

Add the attributes to the manifest before the JAR file is signed.
See Modifying a Manifest File in the Java Tutorial for information on adding attributes to the JAR manifest file.

Permissions Attribute

The Permissions attribute is used to verify that the permissions level requested by the RIA when it runs matches the permissions level that was set when the JAR file was created.

Use this attribute to help prevent someone from re-deploying an application that is signed with your certificate and running it at a different privilege level. Set this attribute to one of the following values:

  • sandbox - runs in the security sandbox and does not require additional permissions.

  • all-permissions - requires access to the user's system resources.

Changes to Security Slider:

The following changes to Security Slider were included in this release(7u51):

  • Block Self-Signed and Unsigned applets on High Security Setting
  • Require Permissions Attribute for High Security Setting
  • Warn users of missing Permissions Attributes for Medium Security Setting

For more information, see Java Control Panel documentation.

enter image description here


Manifest-Version: 1.0
Ant-Version: Apache Ant 1.8.3
Created-By: 1.7.0_51-b13 (Oracle Corporation)
Trusted-Only: true
Class-Path: lib/plugin.jar
Permissions: sandbox
Application-Name: summary-applet

Is there a MessageBox equivalent in WPF?

As the others say, there is a MessageBox in the WPF namespace (System.Windows).

The problem is that it is the same old messagebox with OK, Cancel, etc. Windows Vista and Windows 7 have moved on to use Task Dialogs instead.

Unfortunately there is no easy standard interface for task dialogs. I use an implementation from CodeProject KB.

Generating Random Number In Each Row In Oracle Query

you don’t need a select … from dual, just write:

SELECT t.*, dbms_random.value(1,9) RandomNumber
  FROM myTable t

Set environment variables on Mac OS X Lion

Adding Path Variables to OS X Lion

This was pretty straight forward and worked for me, in terminal:

$echo "export PATH=$PATH:/path/to/whatever" >> .bash_profile #replace "/path/to/whatever" with the location of what you want to add to your bash profile, i.e: $ echo "export PATH=$PATH:/usr/local/Cellar/nginx/1.0.12/sbin" >> .bash_profile 
$. .bash_profile #restart your bash shell

A similar response was here:

UITableview: How to Disable Selection for Some Rows but Not Others

My solution based on data model:

func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -> IndexPath? {
    let rowDetails = viewModel.rowDetails(forIndexPath: indexPath)
    return rowDetails.enabled ? indexPath : nil

func tableView(_ tableView: UITableView, shouldHighlightRowAt indexPath: IndexPath) -> Bool {
    let rowDetails = viewModel.rowDetails(forIndexPath: indexPath)
    return rowDetails.enabled