Programs & Examples On #Maximize window

This tag refers to the process of increasing the size of a UI window to its fullest, so that it takes up the entire screen.

JFrame Maximize window

The way to set JFrame to full-screen, is to set MAXIMIZED_BOTH option which stands for MAXIMIZED_VERT | MAXIMIZED_HORIZ, which respectively set the frame to maximize vertically and horizontally

package Example;
import java.awt.GraphicsConfiguration;
import javax.swing.JFrame;
import javax.swing.JButton;

public class JFrameExample
    static JFrame frame;
    static GraphicsConfiguration gc;
    public static void main(String[] args)
        frame = new JFrame(gc);
        frame.setTitle("Full Screen Example");

        JButton button = new JButton("exit");
        b.addActionListener(new ActionListener(){@Override
        public void actionPerformed(ActionEvent arg0){


YouTube Video Embedded via iframe Ignoring z-index?

Just add one of these two to the src url:



<iframe id="videoIframe" width="500" height="281" src="" frameborder="0" allowfullscreen></iframe>

Why does Maven have such a bad rep?

  • It imposes rigid structure on you from the start.
  • It's XML-based so it's as hard to read as ANT was.
  • Its error reporting is obscure and leaves you stranded when things go wrong.
  • The documentation is poor.
  • It makes hard things easy, and simple things hard.
  • It takes too much time to maintain a Maven build environment, which defeats the point of having an all-singing build system.
  • It takes a long time to figure out that you've found a bug in maven and not configured something wrong. And the bugs do exist, and in surprising places.
  • It promises much but betrays you like a beautiful and seductive but emotionally cold and manipulative lover.

How to add Active Directory user group as login in SQL Server

You can use T-SQL:

use master

I use this as a part of restore from production server to testing machine:

USE master
RESTORE DATABASE yourDbName FROM DISK = 'd:\DropBox\backup\myDB.bak'

You will need to use localized name of services in case of German or French Windows, see How to create a SQL Server login for a service account on a non-English Windows?

What does $(function() {} ); do?

I think you may be confusing Javascript with jQuery methods. Vanilla or plain Javascript is something like:

function example() {

A function of that nature can be called at any time, anywhere.

jQuery (a library built on Javascript) has built in functions that generally required the DOM to be fully rendered before being called. The syntax for when this is completed is:

$(document).ready(function() {

So a jQuery function, which is prefixed with the $ or the word jQuery generally is called from within that method.

$(document).ready(function() {        
    // Assign all list items on the page to be the  color red.  
    //      This does not work until AFTER the entire DOM is "ready", hence the $(document).ready()
    $('li').css('color', 'red');   

The pseudo-code for that block is:

When the document object model $(document) is ready .ready(), call the following function function() { }. In that function, check for all <li>'s on the page $('li') and using the jQuery method .CSS() to set the CSS property "color" to the value "red" .css('color', 'red');

Oracle: If Table Exists

Another method is to define an exception and then only catch that exception letting all others propagate.

   eTableDoesNotExist Exception;
   PRAGMA EXCEPTION_INIT(eTableDoesNotExist, -942);
   EXECUTE IMMEDIATE ('DROP TABLE myschema.mytable');
   When eTableDoesNotExist Then
      DBMS_Output.Put_Line('Table already does not exist.');

7-Zip command to create and extract a password-protected ZIP file on Windows?

General Syntax:

7z a archive_name target parameters

Check your 7-Zip dir. Depending on the release you have, 7z may be replaced with 7za in the syntax.


  • -p encrypt and prompt for PW.
  • -pPUT_PASSWORD_HERE (this replaces -p) if you want to preset the PW with no prompt.
  • -mhe=on to hide file structure, otherwise file structure and names will be visible by default.

Eg. This will prompt for a PW and hide file structures:

7z a archive_name target -p -mhe=on

Eg. No prompt, visible file structure:

7z a archive_name target -pPUT_PASSWORD_HERE

And so on. If you leave target blank, 7z will assume * in current directory and it will recurs directories by default.

Good tool for testing socket connections?

I also found a tool called TCP/IP Test Server [Edit: no longer available from the original developer, but still available via Brothersoft] which seems to do what I need too. But I didn't try it because it is not listed on big freeware-sites (like CNET...) and no source code is published so that it won't reassure a paranoid sysadmin.

How to do a join in linq to sql with method syntax?

Justin has correctly shown the expansion in the case where the join is just followed by a select. If you've got something else, it becomes more tricky due to transparent identifiers - the mechanism the C# compiler uses to propagate the scope of both halves of the join.

So to change Justin's example slightly:

var result = from sc in enumerableOfSomeClass
             join soc in enumerableOfSomeOtherClass
             on sc.Property1 equals soc.Property2
             where sc.X + sc.Y == 10
             select new { SomeClass = sc, SomeOtherClass = soc }

would be converted into something like this:

var result = enumerableOfSomeClass
          sc => sc.Property1,
          soc => soc.Property2,
          (sc, soc) => new { sc, soc })
    .Where(z => + == 10)
    .Select(z => new { SomeClass =, SomeOtherClass = z.soc });

The z here is the transparent identifier - but because it's transparent, you can't see it in the original query :)

How to get function parameter names/values dynamically?

Note: if you want to use ES6 parameter destructuring with the top solution add the following line.

if (result[0] === '{' && result[result.length - 1 === '}']) result = result.slice(1, -1) 4.0 has not been registered

I had the same issue but solved it...... Microsoft has a fix for something close to this that actually worked to solve this issue. you can visit this page

The issue occurs after you installed framework 4.5 and/or framework 4.6. The Visual Studio 2012 Update 5 doesn't fix the issue, I tried that first.

The msdn blog has this to say: "After the installation of the Microsoft .NET Framework 4.6, users may experience the following dialog box displayed in Microsoft Visual Studio when either creating new Web Site or Windows Azure project or when opening existing projects....."

According to the Blog the dialog is benign. just click OK, nothing is effected by the dialog... The comments in the blog suggests that VS 2015 has the same problem, maybe even worse.

Static class initializer in PHP

I am posting this as an answer because this is very important as of PHP 7.4.

The opcache.preload mechanism of PHP 7.4 makes it possible to preload opcodes for classes. If you use it to preload a file that contains a class definition and some side effects, then classes defined in that file will "exist" for all subsequent scripts executed by this FPM server and its workers, but the side effects will not be in effect, and the autoloader will not require the file containing them because the class already "exists". This completely defeats any and all static initialization techniques that rely on executing top-level code in the file that contains the class definition.

isPrime Function for Python Language

def fun(N):#prime test
if N>1 :
    for _ in xrange(5):
        if pow(Num,N-1,N)!=1:
            return False
    return True
return False

True if the number is prime otherwise false

What is console.log in jQuery?

it will print log messages in your developer console (firebug/webkit dev tools/ie dev tools)

Confirm deletion in modal / dialog using Twitter Bootstrap?

GET recipe

For this task you can use already available plugins and bootstrap extensions. Or you can make your own confirmation popup with just 3 lines of code. Check it out.

Say we have this links (note data-href instead of href) or buttons that we want to have delete confirmation for:

<a href="#" data-href="delete.php?id=23" data-toggle="modal" data-target="#confirm-delete">Delete record #23</a>

<button class="btn btn-default" data-href="/delete.php?id=54" data-toggle="modal" data-target="#confirm-delete">
    Delete record #54

Here #confirm-delete points to a modal popup div in your HTML. It should have an "OK" button configured like this:

<div class="modal fade" id="confirm-delete" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
            <div class="modal-body">
            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
                <a class="btn btn-danger btn-ok">Delete</a>

Now you only need this little javascript to make a delete action confirmable:

$('#confirm-delete').on('', function(e) {
    $(this).find('.btn-ok').attr('href', $(e.relatedTarget).data('href'));

So on event delete button href is set to URL with corresponding record id.


POST recipe

I realize that in some cases there might be needed to perform POST or DELETE request rather then GET. It it still pretty simple without too much code. Take a look at the demo below with this approach:

// Bind click to OK button within popup
$('#confirm-delete').on('click', '.btn-ok', function(e) {

  var $modalDiv = $(e.delegateTarget);
  var id = $(this).data('recordId');

  $.post('/api/record/' + id).then(function() {

// Bind to modal opening to set necessary data properties to be used to make request
$('#confirm-delete').on('', function(e) {
  var data = $(e.relatedTarget).data();
  $('.title', this).text(data.recordTitle);
  $('.btn-ok', this).data('recordId', data.recordId);

// Bind click to OK button within popup_x000D_
$('#confirm-delete').on('click', '.btn-ok', function(e) {_x000D_
  var $modalDiv = $(e.delegateTarget);_x000D_
  var id = $(this).data('recordId');_x000D_
  setTimeout(function() {_x000D_
  }, 1000);_x000D_
  // In reality would be something like this_x000D_
  // $modalDiv.addClass('loading');_x000D_
  // $.post('/api/record/' + id).then(function() {_x000D_
  //   $modalDiv.modal('hide').removeClass('loading');_x000D_
  // });_x000D_
// Bind to modal opening to set necessary data properties to be used to make request_x000D_
$('#confirm-delete').on('', function(e) {_x000D_
  var data = $(e.relatedTarget).data();_x000D_
  $('.title', this).text(data.recordTitle);_x000D_
  $('.btn-ok', this).data('recordId', data.recordId);_x000D_
.modal.loading .modal-content:before {_x000D_
  content: 'Loading...';_x000D_
  text-align: center;_x000D_
  line-height: 155px;_x000D_
  font-size: 20px;_x000D_
  background: rgba(0, 0, 0, .8);_x000D_
  position: absolute;_x000D_
  top: 55px;_x000D_
  bottom: 0;_x000D_
  left: 0;_x000D_
  right: 0;_x000D_
  color: #EEE;_x000D_
  z-index: 1000;_x000D_
<script data-require="jquery@*" data-semver="2.0.3" src="//"></script>_x000D_
<script data-require="bootstrap@*" data-semver="3.1.1" src="//"></script>_x000D_
<link data-require="[email protected]" data-semver="3.1.1" rel="stylesheet" href="//" />_x000D_
<div class="modal fade" id="confirm-delete" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">_x000D_
  <div class="modal-dialog">_x000D_
    <div class="modal-content">_x000D_
      <div class="modal-header">_x000D_
        <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>_x000D_
        <h4 class="modal-title" id="myModalLabel">Confirm Delete</h4>_x000D_
      <div class="modal-body">_x000D_
        <p>You are about to delete <b><i class="title"></i></b> record, this procedure is irreversible.</p>_x000D_
        <p>Do you want to proceed?</p>_x000D_
      <div class="modal-footer">_x000D_
        <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>_x000D_
        <button type="button" class="btn btn-danger btn-ok">Delete</button>_x000D_
<a href="#" data-record-id="23" data-record-title="The first one" data-toggle="modal" data-target="#confirm-delete">_x000D_
        Delete "The first one", #23_x000D_
<br />_x000D_
<button class="btn btn-default" data-record-id="54" data-record-title="Something cool" data-toggle="modal" data-target="#confirm-delete">_x000D_
  Delete "Something cool", #54_x000D_


Bootstrap 2.3

Here is an original version of the code I made when I was answering this question for Bootstrap 2.3 modal.

$('#modal').on('show', function() {
    var id = $(this).data('id'),
        removeBtn = $(this).find('.danger');
    removeBtn.attr('href', removeBtn.attr('href').replace(/(&|\?)ref=\d*/, '$1ref=' + id));


How to search multiple columns in MySQL?

If your table is MyISAM:

FROM    pages
WHERE   MATCH(title, content) AGAINST ('keyword' IN BOOLEAN MODE)

This will be much faster if you create a FULLTEXT index on your columns:

CREATE FULLTEXT INDEX fx_pages_title_content ON pages (title, content)

, but will work even without the index.

HTTP POST using JSON in Java

I recomend http-request built on apache http api.

HttpRequest<String> httpRequest = HttpRequestBuilder.createPost(yourUri, String.class)

public void send(){
   ResponseHandler<String> responseHandler = httpRequest.execute("details", yourJsonData);

   int statusCode = responseHandler.getStatusCode();
   String responseContent = responseHandler.orElse(null); // returns Content from response. If content isn't present returns null. 

If you want send JSON as request body you can:

  ResponseHandler<String> responseHandler = httpRequest.executeWithBody(yourJsonData);

I higly recomend read documentation before use.

Open source face recognition for Android

You can try Microsoft's Face API. It can detect and identify people. learn more about face API here.

Flex-box: Align last row to grid

A possible solution is to use justify-content: flex-start; on the .grid container, size restrictions on its children, and margins on the appropriate child elements -- depending on the desired number of columns.

For a 3-column grid, the basic CSS would look like this:

.grid {
    display: flex;
    flex-flow: row wrap;
    justify-content: flex-start;

.grid > * {
    flex: 0 0 32%;
    margin: 1% 0;

.grid > :nth-child(3n-1) {
    margin-left: 2%;
    margin-right: 2%;

It's another imperfect solution, but it works.

Add a user control to a wpf window

Make sure there is an namespace definition (xmlns) for the namespace your control belong to.


Declare an empty two-dimensional array in Javascript?

We usually know the number of columns but maybe not rows (records). Here is an example of my solution making use of much of the above here. (For those here more experienced in JS than me - pretty much everone - any code improvement suggestions welcome)

     var a_cols = [null,null,null,null,null,null,null,null,null];
     var a_rxc  = [[a_cols]];

     // just checking  var arr =  a_rxc.length ; //Array.isArray(a_rxc);
     // alert ("a_rxc length=" + arr) ; Returned 1 
     /* Quick test of array to check can assign new rows to a_rxc. 
        i can be treated as the rows dimension and  j the columns*/
       for (i=0; i<3; i++) {
          for (j=0; j<9; j++) {
            a_rxc[i][j] = i*j;
            alert ("i=" + i + "j=" + j + "  "  + a_rxc[i][j] );
          if (i+1<3) { a_rxc[i+1] = [[a_cols]]; }

And if passing this array to the sever the ajax that works for me is

        jqArrArg1 : a_onedimarray,
        jqArrArg2 : a_rxc
       function(){  },"text" )
        .done(function(srvresp,status) { $("#id_PageContainer").html(srvresp);} ) 
        .fail(function(jqXHR,status) { alert("jqXHR AJAX error " + jqXHR + ">>" + status );} );

Read a text file using Node.js?

The async way of life:

#! /usr/bin/node

const fs = require('fs');

function readall (stream)
  return new Promise ((resolve, reject) => {
    const chunks = [];
    stream.on ('error', (error) => reject (error));
    stream.on ('data',  (chunk) => chunk && chunks.push (chunk));
    stream.on ('end',   ()      => resolve (Buffer.concat (chunks)));

function readfile (filename)
  return readall (fs.createReadStream (filename));

(async () => {
  let content = await readfile ('/etc/ssh/moduli').catch ((e) => {})
  if (content)
    console.log ("size:", content.length,
                 "head:", content.slice (0, 46).toString ());

git switch branch without discarding local changes

You could use --merge/-m git checkout option: git checkout -m <another-branch>

-m --merge

When switching branches, if you have local modifications to one or more files that are different between the current branch and the branch to which you are switching, the command refuses to switch branches in order to preserve your modifications in context. However, with this option, a three-way merge between the current branch, your working tree contents, and the new branch is done, and you will be on the new branch.


Delete item from state array in react

To remove an element from an array, just do:

array.splice(index, 1);

In your case:

removePeople(e) {
  var array = [...this.state.people]; // make a separate copy of the array
  var index = array.indexOf(
  if (index !== -1) {
    array.splice(index, 1);
    this.setState({people: array});

How to grant "grant create session" privilege?

You can grant system privileges with or without the admin option. The default being without admin option.


or with admin option:


The Grantee with the ADMIN OPTION can grant and revoke privileges to other users

Oracle client and networking components were not found

After you install Oracle Client components on the remote server, restart SQL Server Agent from the PC Management Console or directly from Sql Server Management Studio. This will allow the service to load correctly the path to the Oracle components. Otherwise your package will work on design time but fail on run time.

python request with authentication (access_token)

>>> import requests
>>> response = requests.get('', headers={'Authorization': 'access_token myToken'})

If the above doesnt work , try this:

>>> import requests
>>> response = requests.get('', headers={ 'Authorization': 'Bearer <your_token>' })
>>> print response.json()

Sending email with PHP from an SMTP server

There are some SMTP servers that work without authentication, but if the server requires authentication, there is no way to circumvent that.

PHP's built-in mail functions are very limited - specifying the SMTP server is possible in WIndows only. On *nix, mail() will use the OS's binaries.

If you want to send E-Mail to an arbitrary SMTP server on the net, consider using a library like SwiftMailer. That will enable you to use, for example, Google Mail's outgoing servers.

PHP convert date format dd/mm/yyyy => yyyy-mm-dd

Dates in the m/d/y or d-m-y formats are disambiguated by looking at the separator between the various components: if the separator is a slash (/), then the American m/d/y is assumed; whereas if the separator is a dash (-) or a dot (.), then the European d-m-y format is assumed. Check more here.

Use the default date function.

$var = "20/04/2012";
echo date("Y-m-d", strtotime($var) );

EDIT I just tested it, and somehow, PHP doesn't work well with dd/mm/yyyy format. Here's another solution.

$var = '20/04/2012';
$date = str_replace('/', '-', $var);
echo date('Y-m-d', strtotime($date));

How do I keep track of pip-installed packages in an Anaconda (Conda) environment?

I think what's missing here is that when you do:

>pip install .

to install a local package with a, it installs a package that is visible to all the conda envs that use the same version of python. Note I am using the conda version of pip!

e.g., if I'm using python2.7 it puts the local package here:


If I then later create a new conda env with python=2.7 (= the default):

>conda create --name new

>source activate new

And then do:

(new)>conda list    // empty - conda is not aware of any packages yet

However, if I do:

(new)>pip list      // the local package installed above is present

So in this case, conda does not know about the pip package, but the package is available to python.

However, If I instead install the local package (again using pip) after I've created (and activated) the new conda env, now conda sees it:

(new)>conda list   // sees that the package is there and was installed by pip

So I think the interaction between conda and pip has some issues - ie, using pip to install a local package from within one conda env makes that package available (but not seen via conda list) to all other conda envs of the same python version.

What is the most efficient way to create a dictionary of two pandas Dataframe columns?


>>> import pandas as pd
>>> df = pd.DataFrame({'Position':[1,2,3,4,5], 'Letter':['a', 'b', 'c', 'd', 'e']})
>>> dict(sorted(df.values.tolist())) # Sort of sorted... 
{'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
>>> from collections import OrderedDict
>>> OrderedDict(df.values.tolist())
OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5)])

In Long

Explaining solution: dict(sorted(df.values.tolist()))


df = pd.DataFrame({'Position':[1,2,3,4,5], 'Letter':['a', 'b', 'c', 'd', 'e']})


 Letter Position
0   a   1
1   b   2
2   c   3
3   d   4
4   e   5


# Get the values out to a 2-D numpy array, 


array([['a', 1],
       ['b', 2],
       ['c', 3],
       ['d', 4],
       ['e', 5]], dtype=object)

Then optionally:

# Dump it into a list so that you can sort it using `sorted()`
sorted(df.values.tolist()) # Sort by key


# Sort by value:
from operator import itemgetter
sorted(df.values.tolist(), key=itemgetter(1))


[['a', 1], ['b', 2], ['c', 3], ['d', 4], ['e', 5]]

Lastly, cast the list of list of 2 elements into a dict.



{'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}


Answering @sbradbio comment:

If there are multiple values for a specific key and you would like to keep all of them, it's the not the most efficient but the most intuitive way is:

from collections import defaultdict
import pandas as pd

multivalue_dict = defaultdict(list)

df = pd.DataFrame({'Position':[1,2,4,4,4], 'Letter':['a', 'b', 'd', 'e', 'f']})

for idx,row in df.iterrows():


>>> print(multivalue_dict)
defaultdict(list, {1: ['a'], 2: ['b'], 4: ['d', 'e', 'f']})

Bootstrap Navbar toggle button not working

If you will change the ID then Toggle will not working same problem was with me i just change

<div class="collapse navbar-collapse" id="defaultNavbar1">
    <ul class="nav navbar-nav">

id="defaultNavbar1" then toggle is working

Split a large dataframe into a list of data frames based on common value in column

From version 0.8.0, dplyr offers a handy function called group_split():

# On sample data from @Aus_10

df %>%

# A tibble: 25 x 3
   ran_data1 ran_data2 g    
       <dbl>     <dbl> <fct>
 1     2.04      0.627 A    
 2     0.530    -0.703 A    
 3    -0.475     0.541 A    
 4     1.20     -0.565 A    
 5    -0.380    -0.126 A    
 6     1.25     -1.69  A    
 7    -0.153    -1.02  A    
 8     1.52     -0.520 A    
 9     0.905    -0.976 A    
10     0.517    -0.535 A    
# … with 15 more rows

# A tibble: 25 x 3
   ran_data1 ran_data2 g    
       <dbl>     <dbl> <fct>
 1     1.61      0.858 B    
 2     1.05     -1.25  B    
 3    -0.440    -0.506 B    
 4    -1.17      1.81  B    
 5     1.47     -1.60  B    
 6    -0.682    -0.726 B    
 7    -2.21      0.282 B    
 8    -0.499     0.591 B    
 9     0.711    -1.21  B    
10     0.705     0.960 B    
# … with 15 more rows

To not include the grouping column:

df %>%
 group_split(g, keep = FALSE)

g++ ld: symbol(s) not found for architecture x86_64

I had a similar warning/error/failure when I was simply trying to make an executable from two different object files (main.o and add.o). I was using the command:

gcc -o exec main.o add.o

But my program is a C++ program. Using the g++ compiler solved my issue:

g++ -o exec main.o add.o

I was always under the impression that gcc could figure these things out on its own. Apparently not. I hope this helps someone else searching for this error.

Head and tail in one line

>>> mylist = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
>>> head, tail = mylist[0], mylist[1:]
>>> head
>>> tail
[1, 2, 3, 5, 8, 13, 21, 34, 55]

Correct way of looping through C++ arrays

sizeof(texts) on my system evaluated to 96: the number of bytes required for the array and its string instances.

As mentioned elsewhere, the sizeof(texts)/sizeof(texts[0]) would give the value of 3 you were expecting.

How to inflate one view with a layout

layout inflation

View view = null;
LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
view = inflater.inflate(R.layout.mylayout, null);

Spring profiles and testing

@EnableConfigurationProperties needs to be there (you also can annotate your test class), the application-localtest.yml from test/resources will be loaded. A sample with jUnit5

@ContextConfiguration(classes = {YourClasses}, initializers = ConfigFileApplicationContextInitializer.class)
@ActiveProfiles(profiles = "localtest")
class TestActiveProfile {

    void testActiveProfile(){


Simple timeout in java

The example 1 will not compile. This version of it compiles and runs. It uses lambda features to abbreviate it.

 * []
 * Summary: How to roll your own timeouts.
 * Copyright: (c) 2016 Roedy Green, Canadian Mind Products,
 * Licence: This software may be copied and used freely for any purpose but military.
 * Requires: JDK 1.8+
 * Created with: JetBrains IntelliJ IDEA IDE
 * Version History:
 *  1.0 2016-06-28 initial version
package com.mindprod.example;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import static java.lang.System.*;

 * How to roll your own timeouts.
 * Based on code at
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2016-06-28 initial version
 * @since 2016-06-28

public class RollYourOwnTimeout

    private static final long MILLIS_TO_WAIT = 10 * 1000L;

    public static void main( final String[] args )
        final ExecutorService executor = Executors.newSingleThreadExecutor();

        // schedule the work
        final Future<String> future = executor.submit( RollYourOwnTimeout::requestDataFromWebsite );

            // where we wait for task to complete
            final String result = future.get( MILLIS_TO_WAIT, TimeUnit.MILLISECONDS );
            out.println( "result: " + result );

        catch ( TimeoutException e )
            err.println( "task timed out" );
            future.cancel( true /* mayInterruptIfRunning */ );

        catch ( InterruptedException e )
            err.println( "task interrupted" );

        catch ( ExecutionException e )
            err.println( "task aborted" );


 * dummy method to read some data from a website
private static String requestDataFromWebsite()
        // force timeout to expire
        Thread.sleep( 14_000L );
    catch ( InterruptedException e )
    return "dummy";


How to find locked rows in Oracle

Look at the dba_blockers, dba_waiters and dba_locks for locking. The names should be self explanatory.

You could create a job that runs, say, once a minute and logged the values in the dba_blockers and the current active sql_id for that session. (via v$session and v$sqlstats).

You may also want to look in v$sql_monitor. This will be default log all SQL that takes longer than 5 seconds. It is also visible on the "SQL Monitoring" page in Enterprise Manager.

File is universal (three slices), but it does not contain a(n) ARMv7-s slice error for static libraries on iOS, anyway to bypass?

Flurry Support for iPhone 5 (ARMv7s) As I mentioned in yesterday’s post, Flurry started working on a version of the iOS SDK to support the ARMv7s processor in the new iPhone 5 immediately after the announcement on Wednesday.

I am happy to tell you that the work is done and the SDK is now available on the site.

Check if a path represents a file or a folder

String path = "Your_Path";
File f = new File(path);

if (f.isDirectory()){

  }else if(f.isFile()){


Removing Java 8 JDK from Mac

in Mac Remove Java Version using this 3 Commands

java -version

sudo rm -rf /Library/Java/*

sudo rm -rf /Library/PreferencePanes/Java*

sudo rm -rf /Library/Internet\ Plug-Ins/Java*


java -version

//See java was successfully uninstalled.

java -version sudo rm -rf /Library/Java/* sudo rm -rf /Library/PreferencePanes/Java* sudo rm -rf /Library/Internet\ Plug-Ins/Java*

Run java -version

Install Java 8 Link

enter image description here

Download Package and click next next next

Calculating arithmetic mean (one type of average) in Python

I always supposed avg is omitted from the builtins/stdlib because it is as simple as

sum(L)/len(L) # L is some list

and any caveats would be addressed in caller code for local usage already.

Notable caveats:

  1. non-float result: in python2, 9/4 is 2. to resolve, use float(sum(L))/len(L) or from __future__ import division

  2. division by zero: the list may be empty. to resolve:

    if not L:
        raise WhateverYouWantError("foo")
    avg = float(sum(L))/len(L)

href="javascript:" vs. href="javascript:void(0)"

I usually do not use any href and change the aspect with css, making them seems link. Thus you do not have to worry about link effect at all, except for the event handler of your application

a {
  text-recoration: underline;
  cursor: pointer;

Is there a way to follow redirects with command line cURL?

As said, to follow redirects you can use the flag -L or --location:

curl -L

But, if you want limit the number of redirects, add the parameter --max-redirs

--max-redirs <num>

Set maximum number of redirection-followings allowed. If -L, --location is used, this option can be used to prevent curl from following redirections "in absurdum". By default, the limit is set to 50 redirections. Set this option to -1 to make it limitless. If this option is used several times, the last one will be used.

urlencode vs rawurlencode?

It will depend on your purpose. If interoperability with other systems is important then it seems rawurlencode is the way to go. The one exception is legacy systems which expect the query string to follow form-encoding style of spaces encoded as + instead of %20 (in which case you need urlencode).

rawurlencode follows RFC 1738 prior to PHP 5.3.0 and RFC 3986 afterwards (see

Returns a string in which all non-alphanumeric characters except -_.~ have been replaced with a percent (%) sign followed by two hex digits. This is the encoding described in » RFC 3986 for protecting literal characters from being interpreted as special URL delimiters, and for protecting URLs from being mangled by transmission media with character conversions (like some email systems).

Note on RFC 3986 vs 1738. rawurlencode prior to php 5.3 encoded the tilde character (~) according to RFC 1738. As of PHP 5.3, however, rawurlencode follows RFC 3986 which does not require encoding tilde characters.

urlencode encodes spaces as plus signs (not as %20 as done in rawurlencode)(see

Returns a string in which all non-alphanumeric characters except -_. have been replaced with a percent (%) sign followed by two hex digits and spaces encoded as plus (+) signs. It is encoded the same way that the posted data from a WWW form is encoded, that is the same way as in application/x-www-form-urlencoded media type. This differs from the » RFC 3986 encoding (see rawurlencode()) in that for historical reasons, spaces are encoded as plus (+) signs.

This corresponds to the definition for application/x-www-form-urlencoded in RFC 1866.

Additional Reading:

You may also want to see the discussion at

Also, RFC 2396 is worth a look. RFC 2396 defines valid URI syntax. The main part we're interested in is from 3.4 Query Component:

Within a query component, the characters ";", "/", "?", ":", "@",
"&", "=", "+", ",", and "$"
are reserved.

As you can see, the + is a reserved character in the query string and thus would need to be encoded as per RFC 3986 (as in rawurlencode).

"&" meaning after variable type

The & means that the function accepts the address (or reference) to a variable, instead of the value of the variable.

For example, note the difference between this:

void af(int& g)

int main()
    int g = 123;
    cout << g;
    cout << g;
    return 0;

And this (without the &):

void af(int g)

int main()
    int g = 123;
    cout << g;
    cout << g;
    return 0;

Get ALL User Friends Using Facebook Graph API - Android

In v2.0 of the Graph API, calling /me/friends returns the person's friends who also use the app.

In addition, in v2.0, you must request the user_friends permission from each user. user_friends is no longer included by default in every login. Each user must grant the user_friends permission in order to appear in the response to /me/friends. See the Facebook upgrade guide for more detailed information, or review the summary below.

The /me/friendlists endpoint and user_friendlists permission are not what you're after. This endpoint does not return the users friends - its lets you access the lists a person has made to organize their friends. It does not return the friends in each of these lists. This API and permission is useful to allow you to render a custom privacy selector when giving people the opportunity to publish back to Facebook.

If you want to access a list of non-app-using friends, there are two options:

  1. If you want to let your people tag their friends in stories that they publish to Facebook using your App, you can use the /me/taggable_friends API. Use of this endpoint requires review by Facebook and should only be used for the case where you're rendering a list of friends in order to let the user tag them in a post.

  2. If your App is a Game AND your Game supports Facebook Canvas, you can use the /me/invitable_friends endpoint in order to render a custom invite dialog, then pass the tokens returned by this API to the standard Requests Dialog.

In other cases, apps are no longer able to retrieve the full list of a user's friends (only those friends who have specifically authorized your app using the user_friends permission).

For apps wanting allow people to invite friends to use an app, you can still use the Send Dialog on Web or the new Message Dialog on iOS and Android.

How can I export tables to Excel from a webpage

And now there is a better way.

OpenXML SDK for JavaScript.

CSS position absolute full width problem

I don't know if this what you want but try to remove overflow: hidden from #wrap

Google Maps setCenter()

in your code, at line

map.setCenter(new GLatLng(lat, lon), 5);

the setCenter method takes just one parameter, for the lat:long location. Why are you passing two parameters there ?

I suggest you should change it to,

map.setCenter(new GLatLng(lat, lon));

Android Fatal signal 11 (SIGSEGV) at 0x636f7d89 (code=1). How can it be tracked down?

Try disabling Android hardware acceleration in your manifest.


HTML table headers always visible at top of window when viewing a large table

This is really a tricky thing to have a sticky header on your table. I had same requirement but with asp:GridView and then I found it really thought to have sticky header on gridview. There are many solutions available and it took me 3 days trying all the solution but none of them could satisfy.

The main issue that I faced with most of these solutions was the alignment problem. When you try to make the header floating, somehow the alignment of header cells and body cells get off track.

With some solutions, I also got issue of getting header overlapped to first few rows of body, which cause body rows getting hidden behind the floating header.

So now I had to implement my own logic to achieve this, though I also not consider this as perfect solution but this could also be helpful for someone,

Below is the sample table.

<div class="table-holder">
        <table id="MyTable" cellpadding="4" cellspacing="0" border="1px" class="customerTable">
                <tr><th>ID</th><th>First Name</th><th>Last Name</th><th>DOB</th><th>Place</th></tr>

Note: The table is wrapped into a DIV with class attribute equal to 'table-holder'.

Below is the JQuery script that I added in my html page header.

<script src="../Scripts/jquery-1.7.2.min.js" type="text/javascript"></script>
<script src="../Scripts/jquery-ui.min.js" type="text/javascript"></script>
<script type="text/javascript">
    $(document).ready(function () {
        //create var for table holder
        var originalTableHolder = $(".table-holder");
        // set the table holder's with
        originalTableHolder.width($('table', originalTableHolder).width() + 17);
        // Create a clone of table holder DIV
        var clonedtableHolder = originalTableHolder.clone();

        // Calculate height of all header rows.
        var headerHeight = 0;
        $('thead', originalTableHolder).each(function (index, element) {
            headerHeight = headerHeight + $(element).height();

        // Set the position of cloned table so that cloned table overlapped the original
        clonedtableHolder.css('position', 'relative');
        clonedtableHolder.css('top', headerHeight + 'px');

        // Set the height of cloned header equal to header height only so that body is not visible of cloned header
        clonedtableHolder.css('overflow', 'hidden');

        // reset the ID attribute of each element in cloned table
        $('*', clonedtableHolder).each(function (index, element) {
            if ($(element).attr('id')) {
                $(element).attr('id', $(element).attr('id') + '_Cloned');

        originalTableHolder.css('border-bottom', '1px solid #aaa');

        // Place the cloned table holder before original one

and at last below is the CSS class for bit of coloring purpose.


.customerTable thead
    background: #4b6c9e;        

So the whole idea of this logic is to place the table into a table holder div and create clone of that holder at client side when page loaded. Now hide the body of table inside clone holder and position the remaining header part over to original header.

Same solution also works for asp:gridview, you need to add two more steps to achieve this in gridview,

  1. In OnPrerender event of gridview object in your web page, set the table section of header row equal to TableHeader.

    if (this.HeaderRow != null)
        this.HeaderRow.TableSection = TableRowSection.TableHeader;
  2. And wrap your grid into <div class="table-holder"></div>.

Note: if your header has clickable controls then you may need to add some more jQuery script to pass the events raised in cloned header to original header. This code is already available in jQuery sticky-header plugin create by jmosbech

How to locate and insert a value in a text box (input) using Python Selenium?

Assuming your page is available under ""

from selenium import webdriver
from selenium.webdriver.common.keys import Keys

driver = webdriver.Firefox()

Select element by id:

inputElement = driver.find_element_by_id("a1")

Now you can simulate hitting ENTER:


or if it is a form you can submit:


Format a Go string without printing?

I've created go project for string formatting from template (it allow to format strings in C# or Python style, just first version for very simple cases), you could find it here

it works in following manner:

func TestStrFormat(t *testing.T) {
    strFormatResult, err := Format("Hello i am {0}, my age is {1} and i am waiting for {2}, because i am {0}!",
                              "Michael Ushakov (Evillord666)", "34", "\"Great Success\"")
    assert.Nil(t, err)
    assert.Equal(t, "Hello i am Michael Ushakov (Evillord666), my age is 34 and i am waiting for \"Great Success\", because i am Michael Ushakov (Evillord666)!", strFormatResult)

    strFormatResult, err = Format("We are wondering if these values would be replaced : {5}, {4}, {0}", "one", "two", "three")
    assert.Nil(t, err)
    assert.Equal(t, "We are wondering if these values would be replaced : {5}, {4}, one", strFormatResult)

    strFormatResult, err = Format("No args ... : {0}, {1}, {2}")
    assert.Nil(t, err)
    assert.Equal(t, "No args ... : {0}, {1}, {2}", strFormatResult)

func TestStrFormatComplex(t *testing.T) {
    strFormatResult, err := FormatComplex("Hello {user} what are you doing here {app} ?", map[string]string{"user":"vpupkin", "app":"mn_console"})
    assert.Nil(t, err)
    assert.Equal(t, "Hello vpupkin what are you doing here mn_console ?", strFormatResult)

What is the max size of VARCHAR2 in PL/SQL and SQL?

Not sure what you meant with "Can I increase the size of this variable without worrying about the SQL limit?". As long you do not try to insert a more than 4000 VARCHAR2 into a VARCHAR2 SQL column there is nothing to worry about.

Here is the exact reference (this is 11g but true also for 10g)

VARCHAR2 Maximum Size in PL/SQL: 32,767 bytes Maximum Size in SQL 4,000 bytes

Android: how to handle button click

Most used way is, anonymous declaration

    Button send = (Button) findViewById(;
    send.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // handle click

Also you can create View.OnClickListener object and set it to button later, but you still need to override onClick method for example

View.OnClickListener listener = new View.OnClickListener(){
        public void onClick(View v) {
            // handle click
Button send = (Button) findViewById(;

When your activity implements OnClickListener interface you must override onClick(View v) method on activity level. Then you can assing this activity as listener to button, because it already implements interface and overrides the onClick() method

public class MyActivity extends Activity implements View.OnClickListener{

    public void onClick(View v) {
        // handle click

    public void onCreate(Bundle b) {
        Button send = (Button) findViewById(;


(imho) 4-th approach used when multiple buttons have same handler, and you can declare one method in activity class and assign this method to multiple buttons in xml layout, also you can create one method for one button, but in this case I prefer to declare handlers inside activity class.

how to get rid of notification circle in right side of the screen?

This stuff comes from ES file explorer

Just go into this app > settings

Then there is an option that says logging floating window, you just need to disable that and you will get rid of this infernal bubble for good

Is there an embeddable Webkit component for Windows / C# development?

Berkelium is a C++ tool for making chrome embeddable.

AwesomiumDotNet is a wrapper around both Berkelium and Awesomium

BTW, the link here to Awesomium appears to be more current.

How to get Android GPS location

Give it a try :

public LatLng getLocation()
     // Get the location manager
     LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
     Criteria criteria = new Criteria();
     String bestProvider = locationManager.getBestProvider(criteria, false);
     Location location = locationManager.getLastKnownLocation(bestProvider);
     Double lat,lon;
     try {
       lat = location.getLatitude ();
       lon = location.getLongitude ();
       return new LatLng(lat, lon);
     catch (NullPointerException e){
       return null;

Transposing a 1D NumPy array

As some of the comments above mentioned, the transpose of 1D arrays are 1D arrays, so one way to transpose a 1D array would be to convert the array to a matrix like so:

np.transpose(a.reshape(len(a), 1))

Changing Underline color

Update from author:
This answer is outdated since text-decoration-color is now supported by most modern browsers.

:pseudo + em

In order to accurately replicate the size, stroke width, and positioning of the native text-decoration:underline without introducing extra HTML markup, you should use a pseudo-element with em units. This allows for accurate scaling of the element and native behavior without additional markup.


`a {
  text-decoration: none;
  display: inline-table;

a:after {
  content: "";
  border-bottom: 0.1em solid #f00;
  display: table-caption;
  caption-side: bottom;
  position: relative;

By using display:table-caption and caption-side on the pseudo-element and display inline-table, we can force the browser to vertically-align both line and link accurately, even when scaled.

In this instance, we use inline-table instead of inline-block to force the pseudo to display without the need to specify height or negative values.


CODEPEN: | (example with scaling)

Successfully Tested On:
Internet Explorer: 8, 9, 10, 11
Firefox: 41, 40, 39, 38, 37, 36
Chrome: 45, 44, 43, 42
Safari: 8, 7, 6.2
Mobile Safari: 9.0, 8.0
Android Browser: 4.4, 2.3
Dolphin Mobile: 8, 11.4

C# - Winforms - Global Variables

If you're using Visual C#, all you need to do is add a class in Program.cs inheriting Form and change all the inherited class from Form to your class in every Form*.cs.

public class Forms : Form
    //Declare your global valuables here.

public partial class Form1 : Forms    //Change from Form to Forms

Of course, there might be a way to extending the class Form without modifying it. If that's the case, all you need to do is extending it! Since all the forms are inheriting it by default, so all the valuables declared in it will become global automatically! Good luck!!!

What is difference between Axios and Fetch?

Fetch and Axios are very similar in functionality, but for more backwards compatibility Axios seems to work better (fetch doesn't work in IE 11 for example, check this post)

Also, if you work with JSON requests, the following are some differences I stumbled upon with.

Fetch JSON post request

let url = '';
let options = {
            method: 'POST',
            mode: 'cors',
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json;charset=UTF-8'
            body: JSON.stringify({
                property_one: value_one,
                property_two: value_two
let response = await fetch(url, options);
let responseOK = response && response.ok;
if (responseOK) {
    let data = await response.json();
    // do something with data

Axios JSON post request

let url = '';
let options = {
            method: 'POST',
            url: url,
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json;charset=UTF-8'
            data: {
                property_one: value_one,
                property_two: value_two
let response = await axios(options);
let responseOK = response && response.status === 200 && response.statusText === 'OK';
if (responseOK) {
    let data = await;
    // do something with data


  • Fetch's body = Axios' data
  • Fetch's body has to be stringified, Axios' data contains the object
  • Fetch has no url in request object, Axios has url in request object
  • Fetch request function includes the url as parameter, Axios request function does not include the url as parameter.
  • Fetch request is ok when response object contains the ok property, Axios request is ok when status is 200 and statusText is 'OK'
  • To get the json object response: in fetch call the json() function on the response object, in Axios get data property of the response object.

Hope this helps.

How to parse XML using shellscript?

You could try xmllint

The xmllint program parses one or more XML files, specified on the command line as xmlfile. It prints various types of output, depending upon the options selected. It is useful for detecting errors both in XML code and in the XML parser itse

It allows you select elements in the XML doc by xpath, using the --pattern option.

On Mac OS X (Yosemite), it is installed by default.
On Ubuntu, if it is not already installed, you can run apt-get install libxml2-utils

Iterating on a file doesn't work the second time

The file object is a buffer. When you read from the buffer, that portion that you read is consumed (the read position is shifted forward). When you read through the entire file, the read position is at the end of the file (EOF), so it returns nothing because there is nothing left to read.

If you have to reset the read position on a file object for some reason, you can do:

Remove Primary Key in MySQL

First backup the database. Then drop any foreign key associated with the table. truncate the foreign key table.Truncate the current table. Remove the required primary keys. Use sqlyog or workbench or heidisql or dbeaver or phpmyadmin.

boolean in an if statement

I think that your reasoning is sound. But in practice I have found that it is far more common to omit the === comparison. I think that there are three reasons for that:

  1. It does not usually add to the meaning of the expression - that's in cases where the value is known to be boolean anyway.
  2. Because there is a great deal of type-uncertainty in JavaScript, forcing a type check tends to bite you when you get an unexpected undefined or null value. Often you just want your test to fail in such cases. (Though I try to balance this view with the "fail fast" motto).
  3. JavaScript programmers like to play fast-and-loose with types - especially in boolean expressions - because we can.

Consider this example:

var someString = getInput();
var normalized = someString && trim(someString);  
// trim() removes leading and trailing whitespace

if (normalized) {

I think that this kind of code is not uncommon. It handles cases where getInput() returns undefined, null, or an empty string. Due to the two boolean evaluations submitInput() is only called if the given input is a string that contains non-whitespace characters.

In JavaScript && returns its first argument if it is falsy or its second argument if the first argument is truthy; so normalized will be undefined if someString was undefined and so forth. That means that none of the inputs to the boolean expressions above are actually boolean values.

I know that a lot of programmers who are accustomed to strong type-checking cringe when seeing code like this. But note applying strong typing would likely require explicit checks for null or undefined values, which would clutter up the code. In JavaScript that is not needed.

How to edit nginx.conf to increase file size upload

You can increase client_max_body_size and upload_max_filesize + post_max_size all day long. Without adjusting HTTP timeout it will never work.

//You need to adjust this, and probably on PHP side also. client_body_timeout 2min // 1GB fileupload

Differences between and websockets

Using Socket.IO is basically like using jQuery - you want to support older browsers, you need to write less code and the library will provide with fallbacks. uses the websockets technology if available, and if not, checks the best communication type available and uses it.

Parsing JSON in Spring MVC using Jackson JSON

The whole point of using a mapping technology like Jackson is that you can use Objects (you don't have to parse the JSON yourself).

Define a Java class that resembles the JSON you will be expecting.

e.g. this JSON:

"foo" : ["abc","one","two","three"],
"bar" : "true",
"baz" : "1"

could be mapped to this class:

public class Fizzle{
    private List<String> foo;
    private boolean bar;
    private int baz;
    // getters and setters omitted

Now if you have a Controller method like this:

public Fozzle doSomeThing(@RequestBody Fizzle input){
    return new Fozzle(input);

and you pass in the JSON from above, Jackson will automatically create a Fizzle object for you, and it will serialize a JSON view of the returned Object out to the response with mime type application/json.

For a full working example see this previous answer of mine.

Java switch statement: Constant expression required, but it IS constant

Sometimes the switch variable can also make that error for example:

switch(view.getTag()) {//which is an Object type

   case 0://will give compiler error that says Constant expression required


To solve you should cast the variable to int(in this case). So:

switch((int)view.getTag()) {//will be int

   case 0: //No Error


Best design for a changelog / auditing database table?

We also log old and new values and the column they are from as well as the primary key of the table being audited in an audit detail table. Think what you need the audit table for? Not only do you want to know who made a change and when, but when a bad change happens, you want a fast way to put the data back.

While you are designing, you should write the code to recover data. When you need to recover, it is usually in a hurry, best to already be prepared.

AngularJS: Can't I set a variable value on ng-click?

While @tymeJV gave a correct answer, the way to do this to be inline with angular would be:


and then in your controller:

$scope.hidePrefs = function() {  
  $scope.prefs = false;

Is it possible to break a long line to multiple lines in Python?

As far as I know, it can be done. Python has implicit line continuation (inside parentheses, brackets, and strings) for triple-quoted strings ("""like this""")and the indentation of continuation lines is not important. For more info, you may want to read this article on lexical analysis, from

Deep-Learning Nan loss reasons

Regularization can help. For a classifier, there is a good case for activity regularization, whether it is binary or a multi-class classifier. For a regressor, kernel regularization might be more appropriate.

Excel: Search for a list of strings within a particular string using array formulas?

In case others may find this useful: I found that by adding an initial empty cell to my list of search terms, a zero value will be returned instead of error.


NB: Column A has the search terms, B is the row number index.

Set folder for classpath

If you are using Java 6 or higher you can use wildcards of this form:

java -classpath ".;c:\mylibs\*;c:\extlibs\*" MyApp

If you would like to add all subdirectories: lib\a\, lib\b\, lib\c\, there is no mechanism for this in except:

java -classpath ".;c:\lib\a\*;c:\lib\b\*;c:\lib\c\*" MyApp

There is nothing like lib\*\* or lib\** wildcard for the kind of job you want to be done.

TypeScript and field initializers

This is another solution:

return {
  Field1 : "ASD",
  Field2 : "QWE" 
} as myClass;

How do you round a double in Dart to a given degree of precision AFTER the decimal point?

double value = 2.8032739273;
String formattedValue = value.toStringAsFixed(3);

How big can a MySQL database get before performance starts to degrade

I once was called upon to look at a mysql that had "stopped working". I discovered that the DB files were residing on a Network Appliance filer mounted with NFS2 and with a maximum file size of 2GB. And sure enough, the table that had stopped accepting transactions was exactly 2GB on disk. But with regards to the performance curve I'm told that it was working like a champ right up until it didn't work at all! This experience always serves for me as a nice reminder that there're always dimensions above and below the one you naturally suspect.

Angles between two n-dimensional vectors in Python

Note: all of the other answers here will fail if the two vectors have either the same direction (ex, (1, 0, 0), (1, 0, 0)) or opposite directions (ex, (-1, 0, 0), (1, 0, 0)).

Here is a function which will correctly handle these cases:

import numpy as np

def unit_vector(vector):
    """ Returns the unit vector of the vector.  """
    return vector / np.linalg.norm(vector)

def angle_between(v1, v2):
    """ Returns the angle in radians between vectors 'v1' and 'v2'::

            >>> angle_between((1, 0, 0), (0, 1, 0))
            >>> angle_between((1, 0, 0), (1, 0, 0))
            >>> angle_between((1, 0, 0), (-1, 0, 0))
    v1_u = unit_vector(v1)
    v2_u = unit_vector(v2)
    return np.arccos(np.clip(, v2_u), -1.0, 1.0))

Insert/Update Many to Many Entity Framework . How do I do it?

I wanted to add my experience on that. Indeed EF, when you add an object to the context, it changes the state of all the children and related entities to Added. Although there is a small exception in the rule here: if the children/related entities are being tracked by the same context, EF does understand that these entities exist and doesn't add them. The problem happens when for example, you load the children/related entities from some other context or a web ui etc and then yes, EF doesn't know anything about these entities and goes and adds all of them. To avoid that, just get the keys of the entities and find them (e.g. context.Students.FirstOrDefault(s => s.Name == "Alice")) in the same context in which you want to do the addition.

Text file with 0D 0D 0A line breaks

This typically stems from a bug in revision control system, or similar. This was a product from CVS, if a file was checked in from Windows to Unix server, and then checked out again...

In other words, it is just broken...

Prevent users from submitting a form by hitting Enter


$(document).on('keyup keypress', 'form input[type="text"]', function(e) {
  if(e.keyCode == 13) {
    return false;

This solution works on all forms on a website (also on forms inserted with Ajax), preventing only Enters in input texts. Place it in a document ready function, and forget this problem for a life.

How to query for Xml values and attributes from table in SQL Server?

Actually you're close to your goal, you just need to use nodes() method to split your rows and then get values:

    m.c.value('@id', 'varchar(max)') as id,
    m.c.value('@type', 'varchar(max)') as type,
    m.c.value('@unit', 'varchar(max)') as unit,
    m.c.value('@sum', 'varchar(max)') as [sum],
    m.c.value('@count', 'varchar(max)') as [count],
    m.c.value('@minValue', 'varchar(max)') as minValue,
    m.c.value('@maxValue', 'varchar(max)') as maxValue,
    m.c.value('.', 'nvarchar(max)') as Value,
    m.c.value('(text())[1]', 'nvarchar(max)') as Value2
from sqm as s
    outer apply'Sqm/Metrics/Metric') as m(c)

sql fiddle demo

JavaScript single line 'if' statement - best syntax, this alternative?

It can also be done using a single line with while loops and if like this:

if (blah)

It also works with while loops.

How to create an array from a CSV file using PHP and the fgetcsv function

I think the str_getcsv() syntax is much cleaner, it also doesn't require the CSV to be stored in the file system.

$csv = str_getcsv(file_get_contents('myCSVFile.csv'));

echo '<pre>';
echo '</pre>';

Or for a line by line solution:

$csv = array();
$lines = file('myCSVFile.csv', FILE_IGNORE_NEW_LINES);

foreach ($lines as $key => $value)
    $csv[$key] = str_getcsv($value);

echo '<pre>';
echo '</pre>';

Or for a line by line solution with no str_getcsv():

$csv = array();
$file = fopen('myCSVFile.csv', 'r');

while (($result = fgetcsv($file)) !== false)
    $csv[] = $result;


echo '<pre>';
echo '</pre>';

C# - What does the Assert() method do? Is it still useful?

You should use it for times when you don't want to have to breakpoint every little line of code to check variables, but you do want to get some sort of feedback if certain situations are present, for example:

Debug.Assert(someObject != null, "someObject is null! this could totally be a bug!");

Explain ExtJS 4 event handling

One more trick for controller event listeners.

You can use wildcards to watch for an event from any component:

       myCustomEvent: this.doSomething

How do I parse a string to a float or int?

This is a corrected version of

This will try to parse a string and return either int or float depending on what the string represents. It might rise parsing exceptions or have some unexpected behaviour.

  def get_int_or_float(v):
        number_as_float = float(v)
        number_as_int = int(number_as_float)
        return number_as_int if number_as_float == number_as_int else 

In Java, what does NaN mean?

Means Not a Number. It is a common representation for an impossible numeric value in many programming languages.

How do I instantiate a Queue object in java?

Queue is an interface. You can't instantiate an interface directly except via an anonymous inner class. Typically this isn't what you want to do for a collection. Instead, choose an existing implementation. For example:

Queue<Integer> q = new LinkedList<Integer>();


Queue<Integer> q = new ArrayDeque<Integer>();

Typically you pick a collection implementation by the performance and concurrency characteristics you're interested in.

How to recover MySQL database from .myd, .myi, .frm files

If these are MyISAM tables, then plopping the .FRM, .MYD, and .MYI files into a database directory (e.g., /var/lib/mysql/dbname) will make that table available. It doesn't have to be the same database as they came from, the same server, the same MySQL version, or the same architecture. You may also need to change ownership for the folder (e.g., chown -R mysql:mysql /var/lib/mysql/dbname)

Note that permissions (GRANT, etc.) are part of the mysql database. So they won't be restored along with the tables; you may need to run the appropriate GRANT statements to create users, give access, etc. (Restoring the mysql database is possible, but you need to be careful with MySQL versions and any needed runs of the mysql_upgrade utility.)

Actually, you probably just need the .FRM (table structure) and .MYD (table data), but you'll have to repair table to rebuild the .MYI (indexes).

The only constraint is that if you're downgrading, you'd best check the release notes (and probably run repair table). Newer MySQL versions add features, of course.

[Although it should be obvious, if you mix and match tables, the integrity of relationships between those tables is your problem; MySQL won't care, but your application and your users may. Also, this method does not work at all for InnoDB tables. Only MyISAM, but considering the files you have, you have MyISAM]

Define static method in source-file with declaration in header-file in C++

Keywords static and virtual should not be repeated in the definition. They should only be used in the class declaration.

Concatenating Matrices in R

cbindX from the package gdata combines multiple columns of differing column and row lengths. Check out the page here:

It takes multiple comma separated matrices and data.frames as input :) You just need to

install.packages("gdata", dependencies=TRUE)

and then

concat_data <- cbindX(df1, df2, df3) # or cbindX(matrix1, matrix2, matrix3, matrix4)

How to redirect DNS to different ports

Possible solutions:

  1. Use nginx on the server as a proxy that will listen to port A and multiplex to port B or C.

  2. If you use AWS you can use the load balancer to redirect the request to specific port based on the host.

How to implement a SQL like 'LIKE' operator in java?

Check out

It's a zero dependency library in Java for doing glob (and sql like) type of comparisons. Over a large data set it is faster than translating to a regular expression.

Basic syntax

MatchingEngine m = GlobPattern.compile("dog%cat\%goat_", '%', '_', GlobPattern.HANDLE_ESCAPES);
if (m.matches(str)) { ... }

Creating a Shopping Cart using only HTML/JavaScript

Here's a one page cart written in Javascript with localStorage. Here's a full working pen. Previously found on Codebox


var cart = {
  hPdt : null, // HTML products list
  hItems : null, // HTML current cart
  items : {}, // Current

  save : function () {
    localStorage.setItem("cart", JSON.stringify(cart.items));

  load : function () {
    cart.items = localStorage.getItem("cart");
    if (cart.items == null) { cart.items = {}; }
    else { cart.items = JSON.parse(cart.items); }

  nuke : function () {
    if (confirm("Empty cart?")) {
      cart.items = {};

  init : function () {
    cart.hPdt = document.getElementById("cart-products");
    cart.hItems = document.getElementById("cart-items");

    cart.hPdt.innerHTML = "";
    let p, item, part;
    for (let id in products) {
      // WRAPPER
      p = products[id];
      item = document.createElement("div");
      item.className = "p-item";

      part = document.createElement("img");
      part.src = "images/" +p.img;
      part.className = "p-img";

      part = document.createElement("div");
      part.innerHTML =;
      part.className = "p-name";

      part = document.createElement("div");
      part.innerHTML = p.desc;
      part.className = "p-desc";

      part = document.createElement("div");
      part.innerHTML = "$" + p.price;
      part.className = "p-price";

      // ADD TO CART
      part = document.createElement("input");
      part.type = "button";
      part.value = "Add to Cart";
      part.className = "cart p-add";
      part.onclick = cart.add; = id;



  list : function () {
    // (D1) RESET
    cart.hItems.innerHTML = "";
    let item, part, pdt;
    let empty = true;
    for (let key in cart.items) {
      if(cart.items.hasOwnProperty(key)) { empty = false; break; }

    // (D2) CART IS EMPTY
    if (empty) {
      item = document.createElement("div");
      item.innerHTML = "Cart is empty";

    else {
      let p, total = 0, subtotal = 0;
      for (let id in cart.items) {
        // ITEM
        p = products[id];
        item = document.createElement("div");
        item.className = "c-item";

        // NAME
        part = document.createElement("div");
        part.innerHTML =;
        part.className = "c-name";

        // REMOVE
        part = document.createElement("input");
        part.type = "button";
        part.value = "X"; = id;
        part.className = "c-del cart";
        part.addEventListener("click", cart.remove);

        // QUANTITY
        part = document.createElement("input");
        part.type = "number";
        part.value = cart.items[id]; = id;
        part.className = "c-qty";
        part.addEventListener("change", cart.change);

        // SUBTOTAL
        subtotal = cart.items[id] * p.price;
        total += subtotal;

      item = document.createElement("input");
      item.type = "button";
      item.value = "Empty";
      item.addEventListener("click", cart.nuke);
      item.className = "c-empty cart";

      item = document.createElement("input");
      item.type = "button";
      item.value = "Checkout - " + "$" + total;
      item.addEventListener("click", cart.checkout);
      item.className = "c-checkout cart";

  add : function () {
    if (cart.items[] == undefined) {
      cart.items[] = 1;
    } else {

  change : function () {
    if (this.value == 0) {
      delete cart.items[];
    } else {
      cart.items[] = this.value;
  remove : function () {
    delete cart.items[];;
  checkout : function () {
    // CHECKS
    // PAYMENT
    alert("TO DO");

    var data = new FormData();
    data.append('cart', JSON.stringify(cart.items));
    data.append('products', JSON.stringify(products));
    var xhr = new XMLHttpRequest();"POST", "SERVER-SCRIPT");
    xhr.onload = function(){ ... };
window.addEventListener("DOMContentLoaded", cart.init);

How to round up a number to nearest 10?

There are many anwers in this question, probably all will give you the answer you are looking for. But as @TallGreenTree mentions, there is a function for this.

But the problem of the answer of @TallGreenTree is that it doesn't round up, it rounds to the nearest 10. To solve this, add +5 to your number in order to round up. If you want to round down, do -5.

So in code:

round($num + 5, -1);

You can't use the round mode for rounding up, because that only rounds up fractions and not whole numbers.

If you want to round up to the nearest 100, you shoud use +50.

Using column alias in WHERE clause of MySQL query produces an error

As Victor pointed out, the problem is with the alias. This can be avoided though, by putting the expression directly into the WHERE x IN y clause:

SELECT `users`.`first_name`,`users`.`last_name`,`users`.`email`,SUBSTRING(`locations`.`raw`,-6,4) AS `guaranteed_postcode`
FROM `users` LEFT OUTER JOIN `locations`
ON `users`.`id` = `locations`.`user_id`
WHERE SUBSTRING(`locations`.`raw`,-6,4) NOT IN #this is where the fake col is being used
 SELECT `postcode` FROM `postcodes` WHERE `region` IN

However, I guess this is very inefficient, since the subquery has to be executed for every row of the outer query.

Composer: The requested PHP extension ext-intl * is missing from your system

To enable intl extension follow the instructions below.

You need enable extension by uncommenting the following line extension=php_intl.dll in the C:\xampp\php\php.ini file. Once you uncomment the extension=php_intl.dll, then you must restart apache server using XAMPP control panel.

//about line 998
change as

(Note: php.ini file mostly in the following directory C:\xampp\php)

Restart xampp

How to install SQL Server Management Studio 2012 (SSMS) Express?

Good evening,

The previous clues to get SQLManagementStudio_x64_ENU.exe runing didn't work as stated for me. After a while of searching, trying, retrying again and again, I finally figured it out. When executing SQLManagementStudio_x64_ENU.exe on my Windows seven system, I kept runing into compatibility issues. The trick is to run SQLManagementStudio_x64_ENU.exe in compatibility mode with Windows XP SP2. Edit the installer properties and enable compatibility mode with XP (service pack 2), then you'll be able to access Mr Doug (answered Mar 4 at 15:09) resolution.


Chrome Uncaught Syntax Error: Unexpected Token ILLEGAL

I get the same error in Chrome after pasting code copied from jsfiddle.

If you select all the code from a panel in jsfiddle and paste it into the free text editor Notepad++, you should be able to see the problem character as a question mark "?" at the very end of your code. Delete this question mark, then copy and paste the code from Notepad++ and the problem will be gone.

Convert JSONObject to Map

org.json.JSONObject#toMap() will do to work

if-else statement inside jsx: ReactJS

Just Tried that:

      main-condition-1 && 
      main-condition-2 &&
      (sub-condition ? (<p>Hi</p>) : (<p>Hello</p>))

Let me know what you guys think!!!

C# JSON Serialization of Dictionary into {key:value, ...} instead of {key:key, value:value, ...}

I'm using out of the box MVC4 with this code (note the two parameters inside ToDictionary)

 var result = new JsonResult()
     Data = new
         partials = GetPartials(data.Partials).ToDictionary(x => x.Key, y=> y.Value)

I get what's expected:

{"partials":{"cartSummary":"\u003cb\u003eCART SUMMARY\u003c/b\u003e"}}

Important: WebAPI in MVC4 uses JSON.NET serialization out of the box, but the standard web JsonResult action result doesn't. Therefore I recommend using a custom ActionResult to force JSON.NET serialization. You can also get nice formatting

Here's a simple actionresult JsonNetResult

You'll see the difference (and can make sure you're using the right one) when serializing a date:

Microsoft way:




Check if table exists

I don't actually find any of the presented solutions here to be fully complete so I'll add my own. Nothing new here. You can stitch this together from the other presented solutions plus various comments.

There are at least two things you'll have to make sure:

  1. Make sure you pass the table name to the getTables() method, rather than passing a null value. In the first case you let the database server filter the result for you, in the second you request a list of all tables from the server and then filter the list locally. The former is much faster if you are only searching for a single table.

  2. Make sure to check the table name from the resultset with an equals match. The reason is that the getTables() does pattern matching on the query for the table and the _ character is a wildcard in SQL. Suppose you are checking for the existence of a table named EMPLOYEE_SALARY. You'll then get a match on EMPLOYEESSALARY too which is not what you want.

Ohh, and do remember to close those resultsets. Since Java 7 you would want to use a try-with-resources statement for that.

Here's a complete solution:

public static boolean tableExist(Connection conn, String tableName) throws SQLException {
    boolean tExists = false;
    try (ResultSet rs = conn.getMetaData().getTables(null, null, tableName, null)) {
        while ( { 
            String tName = rs.getString("TABLE_NAME");
            if (tName != null && tName.equals(tableName)) {
                tExists = true;
    return tExists;

You may want to consider what you pass as the types parameter (4th parameter) on your getTables() call. Normally I would just leave at null because you don't want to restrict yourself. A VIEW is as good as a TABLE, right? These days many databases allow you to update through a VIEW so restricting yourself to only TABLE type is in most cases not the way to go. YMMV.

Best practice to run Linux service as a different user

Just to add some other things to watch out for:

  • Sudo in a init.d script is no good since it needs a tty ("sudo: sorry, you must have a tty to run sudo")
  • If you are daemonizing a java application, you might want to consider Java Service Wrapper (which provides a mechanism for setting the user id)
  • Another alternative could be su --session-command=[cmd] [user]

How to convert date into this 'yyyy-MM-dd' format in angular 2

A simple solution would be to just write = new Date().toLocaleDateString();

date .toLocaleDateString() time .toLocaleTimeString() both .toLocaleString()

Hope this helps.

How to show git log history (i.e., all the related commits) for a sub directory of a git repo?

The other answers only show the changed files.

git log -p DIR is very useful, if you need the full diff of all changed files in a specific subdirectory.

Example: Show all detailed changes in a specific version range

git log -p 8a5fb..HEAD -- A B

commit 62ad8c5d
Author: Scott Tiger
Date:   Mon Nov 27 14:25:29 2017 +0100

    My comment

@@ -216,6 +216,10 @@ public class MyClass {

+  Added
-  Deleted

How to check if a Unix .tar.gz file is a valid file without uncompressing?

These are all very sub-optimal solutions. From the GZIP spec

ID2 (IDentification 2)
These have the fixed values ID1 = 31 (0x1f, \037), ID2 = 139 (0x8b, \213), to identify the file as being in gzip format.

Has to be coded into whatever language you're using.

CSS3 opacity gradient?

We can do it by css like.

body {
  background: #000;
  background-image: linear-gradient(90deg, rgba(255, 255, 255, .3) 0%, rgba(231, 231, 231, .3) 22.39%, rgba(209, 209, 209,  .3) 42.6%, rgba(182, 182, 182, .3) 79.19%, rgba(156, 156, 156, .3) 104.86%);

How do I pass an object from one activity to another on Android?

This answer is specific to situations where the objects to be passed has nested class structure. With nested class structure, making it Parcelable or Serializeable is a bit tedious. And, the process of serialising an object is not efficient on Android. Consider the example below,

class Myclass    {
  int a;
  class SubClass    {
       int b;

With Google's GSON library, you can directly parse an object into a JSON formatted String and convert it back to the object format after usage. For example,

MyClass src = new MyClass();
Gson gS = new Gson();
String target = gS.toJson(src); // Converts the object to a JSON String

Now you can pass this String across activities as a StringExtra with the activity intent.

Intent i = new Intent(FromActivity.this, ToActivity.class);
i.putExtra("MyObjectAsString", target);

Then in the receiving activity, create the original object from the string representation.

String target = getIntent().getStringExtra("MyObjectAsString");
MyClass src = gS.fromJson(target, MyClass.class); // Converts the JSON String to an Object

It keeps the original classes clean and reusable. Above of all, if these class objects are created from the web as JSON objects, then this solution is very efficient and time saving.


While the above explained method works for most situations, for obvious performance reasons, do not rely on Android's bundled-extra system to pass objects around. There are a number of solutions makes this process flexible and efficient, here are a few. Each has its own pros and cons.

  1. Eventbus
  2. Otto

How to enable C++17 compiling in Visual Studio?

Visual studio 2019 version:

The drop down menu was moved to:

  • Right click on project (not solution)
  • Properties (or Alt + Enter)
  • From the left menu select Configuration Properties
  • General
  • In the middle there is an option called "C++ Language Standard"
  • Next to it is the drop down menu
  • Here you can select Default, ISO C++ 14, 17 or latest

Get value of input field inside an iframe

<iframe id="upload_target" name="upload_target">
    <textarea rows="20" cols="100" name="result" id="result" ></textarea>
    <input type="text" id="txt1" />

You can Get value by JQuery


work on only same domain link

Where does Android app package gets installed on phone

You will find the application folder at:

/data/data/"your package name"

you can access this folder using the DDMS for your Emulator. you can't access this location on a real device unless you have a rooted device.

Hiding a sheet in Excel 2007 (with a password) OR hide VBA code in Excel


If the user is sophisticated or determined enough to:

  1. Open the Excel VBA editor
  2. Use the object browser to see the list of all sheets, including VERYHIDDEN ones
  3. Change the property of the sheet to VISIBLE or just HIDDEN

then they are probably sophisticated or determined enough to:

  1. Search the internet for "remove Excel 2007 project password"
  2. Apply the instructions they find.

So what's on this hidden sheet? Proprietary information like price formulas, or client names, or employee salaries? Putting that info in even an hidden tab probably isn't the greatest idea to begin with.

Simple way to create matrix of random numbers

Take a look at numpy.random.rand:

Docstring: rand(d0, d1, ..., dn)

Random values in a given shape.

Create an array of the given shape and propagate it with random samples from a uniform distribution over [0, 1).

>>> import numpy as np
>>> np.random.rand(2,3)
array([[ 0.22568268,  0.0053246 ,  0.41282024],
       [ 0.68824936,  0.68086462,  0.6854153 ]])

How to Set user name and Password of phpmyadmin

You can simply open the phpmyadmin page from your browser, then open any existing database -> go to Privileges tab, click on your root user and then a popup window will appear, you can set your password there.. Hope this Helps.

Debug/run standard java in Visual Studio Code IDE and OS X?

There is a much easier way to run Java, no configuration needed:

  1. Install the Code Runner Extension
  2. Open your Java code file in Text Editor, then use shortcut Ctrl+Alt+N, or press F1 and then select/type Run Code, or right click the Text Editor and then click Run Code in context menu, the code will be compiled and run, and the output will be shown in the Output Window.


SCCM 2012 application install "Failed" in client Software Center

The execmgr.log will show the commandline and ccmcache folder used for installation. Typically, required apps don't show on appenforce.log and some clients will have outdated appenforce or no ppenforce.log files. execmgr.log also shows required hidden uninstall actions as well.

You may want to save the blog link. I still reference it from time to time.

How to find which version of TensorFlow is installed in my system?

If you have TensorFlow 2.x:

sess = tf.compat.v1.Session(config=tf.compat.v1.ConfigProto(log_device_placement=True))

Excel 2013 VBA Clear All Filters macro

I found this workaround to work pretty effectively. It basically removes autofilter from the table and then re-applies it, thus removing any previous filters. From my experience this is not prone to the error handling required with the other methods mentioned here.

Set myTable = YOUR_SHEET.ListObjects("YourTableName")

myTable.ShowAutoFilter = False
myTable.ShowAutoFilter = True

TypeError: unhashable type: 'numpy.ndarray'

Your variable energies probably has the wrong shape:

>>> from numpy import array
>>> set([1,2,3]) & set(range(2, 10))
set([2, 3])
>>> set(array([1,2,3])) & set(range(2,10))
set([2, 3])
>>> set(array([[1,2,3],])) & set(range(2,10))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'numpy.ndarray'

And that's what happens if you read columnar data using your approach:

>>> data
array([[  1.,   2.,   3.],
       [  3.,   4.,   5.],
       [  5.,   6.,   7.],
       [  8.,   9.,  10.]])
>>> hsplit(data,3)[0]
array([[ 1.],
       [ 3.],
       [ 5.],
       [ 8.]])

Probably you can simply use

>>> data[:,0]
array([ 1.,  3.,  5.,  8.])


(P.S. Your code looks like it's undecided about whether it's data or elementdata. I've assumed it's simply a typo.)

Print DIV content by JQuery

your question doesn't sound as if you even tried it yourself, so i shouldn't even think of answering, but: if a hidden div can't be printed with that one line:


simply change it to:


which should make it work in all cases.

for the rest, there's no solution. the plugin will open the print-dialog for you where the user has to choose his printer. you simply can't find out if a printer is attached with javascript (and you (almost) can't print without print-dialog - if you're thinking about that).


The $.browser object has been removed in version 1.9.x of jQuery making this library unsupported.

Inner join of DataTables in C#

I wanted a function that would join tables without requiring you to define the columns using an anonymous type selector, but had a hard time finding any. I ended up having to make my own. Hopefully this will help anyone in the future who searches for this:

private DataTable JoinDataTables(DataTable t1, DataTable t2, params Func<DataRow, DataRow, bool>[] joinOn)
    DataTable result = new DataTable();
    foreach (DataColumn col in t1.Columns)
        if (result.Columns[col.ColumnName] == null)
            result.Columns.Add(col.ColumnName, col.DataType);
    foreach (DataColumn col in t2.Columns)
        if (result.Columns[col.ColumnName] == null)
            result.Columns.Add(col.ColumnName, col.DataType);
    foreach (DataRow row1 in t1.Rows)
        var joinRows = t2.AsEnumerable().Where(row2 =>
                foreach (var parameter in joinOn)
                    if (!parameter(row1, row2)) return false;
                return true;
        foreach (DataRow fromRow in joinRows)
            DataRow insertRow = result.NewRow();
            foreach (DataColumn col1 in t1.Columns)
                insertRow[col1.ColumnName] = row1[col1.ColumnName];
            foreach (DataColumn col2 in t2.Columns)
                insertRow[col2.ColumnName] = fromRow[col2.ColumnName];
    return result;

An example of how you might use this:

var test = JoinDataTables(transactionInfo, transactionItems,
               (row1, row2) =>
               row1.Field<int>("TransactionID") == row2.Field<int>("TransactionID"));

One caveat: This is certainly not optimized, so be mindful when getting to row counts above 20k. If you know that one table will be larger than the other, try to put the smaller one first and the larger one second.

How to read multiple Integer values from a single line of input in Java?

Better get the whole line as a string and then use StringTokenizer to get the numbers (using space as delimiter ) and then parse them as integers . This will work for n number of integers in a line .

    Scanner sc = new Scanner(;
    List<Integer> l = new LinkedList<>(); // use linkedlist to save order of insertion
    StringTokenizer st = new StringTokenizer(sc.nextLine(), " "); // whitespace is the delimiter to create tokens
    while(st.hasMoreTokens())  // iterate until no more tokens
        l.add(Integer.parseInt(st.nextToken()));  // parse each token to integer and add to linkedlist


Iterating through a string word by word

This is one way to do it:

string = "this is a string"
ssplit = string.split()
for word in ssplit:
    print (word)



How to move git repository with all branches from bitbucket to github?

Here are the steps to move a private Git repository:

Step 1: Create Github repository

First, create a new private repository on It’s important to keep the repository empty, e.g. don’t check option Initialize this repository with a README when creating the repository.

Step 2: Move existing content

Next, we need to fill the Github repository with the content from our Bitbucket repository:

  1. Check out the existing repository from Bitbucket:
    $ git clone https://[email protected]/USER/PROJECT.git
  1. Add the new Github repository as upstream remote of the repository checked out from Bitbucket:
    $ cd PROJECT
    $ git remote add upstream
  1. Push all branches (below: just master) and tags to the Github repository:
    $ git push upstream master
    $ git push --tags upstream

Step 3: Clean up old repository

Finally, we need to ensure that developers don’t get confused by having two repositories for the same project. Here is how to delete the Bitbucket repository:

  1. Double-check that the Github repository has all content

  2. Go to the web interface of the old Bitbucket repository

  3. Select menu option Setting > Delete repository

  4. Add the URL of the new Github repository as redirect URL

With that, the repository completely settled into its new home at Github. Let all the developers know!

HTML 5 Favicon - Support?

The answers provided (at the time of this post) are link only answers so I thought I would summarize the links into an answer and what I will be using.

When working to create Cross Browser Favicons (including touch icons) there are several things to consider.

The first (of course) is Internet Explorer. IE does not support PNG favicons until version 11. So our first line is a conditional comment for favicons in IE 9 and below:

<!--[if IE]><link rel="shortcut icon" href="path/to/favicon.ico"><![endif]-->

To cover the uses of the icon create it at 32x32 pixels. Notice the rel="shortcut icon" for IE to recognize the icon it needs the word shortcut which is not standard. Also we wrap the .ico favicon in a IE conditional comment because Chrome and Safari will use the .ico file if it is present, despite other options available, not what we would like.

The above covers IE up to IE 9. IE 11 accepts PNG favicons, however, IE 10 does not. Also IE 10 does not read conditional comments thus IE 10 won't show a favicon. With IE 11 and Edge available I don't see IE 10 in widespread use, so I ignore this browser.

For the rest of the browsers we are going to use the standard way to cite a favicon:

<link rel="icon" href="path/to/favicon.png">

This icon should be 196x196 pixels in size to cover all devices that may use this icon.

To cover touch icons on mobile devices we are going to use Apple's proprietary way to cite a touch icon:

<link rel="apple-touch-icon-precomposed" href="apple-touch-icon-precomposed.png">

Using rel="apple-touch-icon-precomposed" will not apply the reflective shine when bookmarked on iOS. To have iOS apply the shine use rel="apple-touch-icon". This icon should be sized to 180x180 pixels as that is the current size recommend by Apple for the latest iPhones and iPads. I have read Blackberry will also use rel="apple-touch-icon-precomposed".

As a note: Chrome for Android states:

The apple-touch-* are deprecated, and will be supported only for a short time. (Written as of beta for m31 of Chrome).

Custom Tiles for IE 11+ on Windows 8.1+

IE 11+ on Windows 8.1+ does offer a way to create pinned tiles for your site.

Microsoft recommends creating a few tiles at the following size:

Small: 128 x 128

Medium: 270 x 270

Wide: 558 x 270

Large: 558 x 558

These should be transparent images as we will define a color background next.

Once these images are created you should create an xml file called browserconfig.xml with the following code:

<?xml version="1.0" encoding="utf-8"?>
      <square70x70logo src="images/smalltile.png"/>
      <square150x150logo src="images/mediumtile.png"/>
      <wide310x150logo src="images/widetile.png"/>
      <square310x310logo src="images/largetile.png"/>

Save this xml file in the root of your site. When a site is pinned IE will look for this file. If you want to name the xml file something different or have it in a different location add this meta tag to the head:

<meta name="msapplication-config" content="path-to-browserconfig/custom-name.xml" />

For additional information on IE 11+ custom tiles and using the XML file visit Microsoft's website.

Putting it all together:

To put it all together the above code would look like this:

<!-- For IE 9 and below. ICO should be 32x32 pixels in size -->
<!--[if IE]><link rel="shortcut icon" href="path/to/favicon.ico"><![endif]-->

<!-- Touch Icons - iOS and Android 2.1+ 180x180 pixels in size. --> 
<link rel="apple-touch-icon-precomposed" href="apple-touch-icon-precomposed.png">

<!-- Firefox, Chrome, Safari, IE 11+ and Opera. 196x196 pixels in size. -->
<link rel="icon" href="path/to/favicon.png">

Windows Phone Live Tiles

If a user is using a Windows Phone they can pin a website to the start screen of their phone. Unfortunately, when they do this it displays a screenshot of your phone, not a favicon (not even the MS specific code referenced above). To make a "Live Tile" for Windows Phone Users for your website one must use the following code:

Here are detailed instructions from Microsoft but here is a synopsis:

Step 1

Create a square image for your website, to support hi-res screens create it at 768x768 pixels in size.

Step 2

Add a hidden overlay of this image. Here is example code from Microsoft:

<div id="TileOverlay" onclick="ToggleTileOverlay()" style='background-color: Highlight; height: 100%; width: 100%; top: 0px; left: 0px; position: fixed; color: black; visibility: hidden'>
  <img src="customtile.png" width="320" height="320" />
  <div style='margin-top: 40px'>
     Add text/graphic asking user to pin to start using the menu...

Step 3

You then can add thew following line to add a pin to start link:

<a href="javascript:ToggleTileOverlay()">Pin this site to your start screen</a>

Microsoft recommends that you detect windows phone and only show that link to those users since it won't work for other users.

Step 4

Next you add some JS to toggle the overlay visibility

function ToggleTileOverlay() {
 var newVisibility =     (document.getElementById('TileOverlay').style.visibility == 'visible') ? 'hidden' : 'visible';
 document.getElementById('TileOverlay').style.visibility =    newVisibility;

Note on Sizes

I am using one size as every browser will scale down the image as necessary. I could add more HTML to specify multiple sizes if desired for those with a lower bandwidth but I am already compressing the PNG files heavily using TinyPNG and I find this unnecessary for my purposes. Also, according to philippe_b's answer Chrome and Firefox have bugs that cause the browser to load all sizes of icons. Using one large icon may be better than multiple smaller ones because of this.

Further Reading

For those who would like more details see the links below:

How can I call a function using a function pointer?

This has been more than adequately answered, but you may find this useful: The Function Pointer Tutorials. It is a truly comprehensive treatment of the subject in five chapters!

How I can filter a Datatable?

It is better to use DataView for this task.

Example of the using it you can find in this post: How to filter data in dataview

How can I build a recursive function in python?

Recursion in Python works just as recursion in an other language, with the recursive construct defined in terms of itself:

For example a recursive class could be a binary tree (or any tree):

class tree():
    def __init__(self):
        '''Initialise the tree'''
        self.Data = None
        self.Count = 0
        self.LeftSubtree = None
        self.RightSubtree = None

    def Insert(self, data):
        '''Add an item of data to the tree'''
        if self.Data == None:
            self.Data = data
            self.Count += 1
        elif data < self.Data:
            if self.LeftSubtree == None:
                # tree is a recurive class definition
                self.LeftSubtree = tree()
            # Insert is a recursive function
        elif data == self.Data:
            self.Count += 1
        elif data > self.Data:
            if self.RightSubtree == None:
                self.RightSubtree = tree()

if __name__ == '__main__':
    T = tree()
    # The root node
    # Will be put into the left subtree
    # Will be put into the right subtree

As already mentioned a recursive structure must have a termination condition. In this class, it is not so obvious because it only recurses if new elements are added, and only does it a single time extra.

Also worth noting, python by default has a limit to the depth of recursion available, to avoid absorbing all of the computer's memory. On my computer this is 1000. I don't know if this changes depending on hardware, etc. To see yours :

import sys

and to set it :

import sys #(if you haven't already)

edit: I can't guarentee that my binary tree is the most efficient design ever. If anyone can improve it, I'd be happy to hear how

SQL Server: How to use UNION with two queries that BOTH have a WHERE clause?

select * from 
    select top 2 t1.ID, t1.ReceivedDate
    from Table t1
    where t1.Type = 'TYPE_1'
    order by t1.ReceivedDate de
) t1
select * from 
    select top 2 t2.ID
    from Table t2
    where t2.Type = 'TYPE_2'
    order by t2.ReceivedDate desc
) t2

or using CTE (SQL Server 2005+)

;with One as
    select top 2 t1.ID, t1.ReceivedDate
    from Table t1
    where t1.Type = 'TYPE_1'
    order by t1.ReceivedDate de
,Two as
    select top 2 t2.ID
    from Table t2
    where t2.Type = 'TYPE_2'
    order by t2.ReceivedDate desc
select * from One
select * from Two

How to square all the values in a vector in R?

Try this (faster and simpler):

newData <- data^2

"Auth Failed" error with EGit and GitHub

My answer may be outdated but hopefully it can be useful for someone.

  1. In your Eclipse go to Window > Preferences > General > Network Connections > SSH2 (or just type "SSH2" in preferences window filter box).

  2. In "Key Management" tab press "Generate RSA Key..." button. Optionally you can add comment (usually e-mail address) and passphrase to your key. Passphrase will be used during authentication on GitHub.

  3. Copy your generated public key (in a box just below "Generate RSA Key..." button) and add it to your GitHub account.
  4. Press "Save Private Key..." button to save your private RSA key into file. By default keys are stored in SSH2 home directory (see "General" tab).

That's it! Now you should be able to push your code to GitHub repo.

MVC Razor view nested foreach's model

It is clear from the error.

The HtmlHelpers appended with "For" expects lambda expression as a parameter.

If you are passing the value directly, better use Normal one.


Instead of TextboxFor(....) use Textbox()

syntax for TextboxFor will be like Html.TextBoxFor(m=>m.Property)

In your scenario you can use basic for loop, as it will give you index to use.

@for(int i=0;i<Model.Theme.Count;i++)
   @for(int j=0;j<Model.Theme[i].Products.Count;j++) )
      @for(int k=0;k<Model.Theme[i].Products[j].Orders.Count;k++)

VBA shorthand for x=x+1?

Sadly there are no operation-assignment operators in VBA.

(Addition-assignment += are available in VB.Net)

Pointless workaround;

Sub Inc(ByRef i As Integer)
   i = i + 1  
End Sub
Static value As Integer
inc value
inc value

How to get a thread and heap dump of a Java process on Windows that's not running in a console

In addition to using the mentioned jconsole/visualvm, you can use jstack -l <vm-id> on another command line window, and capture that output.

The <vm-id> can be found using the task manager (it is the process id on windows and unix), or using jps.

Both jstack and jps are include in the Sun JDK version 6 and higher.

Aligning text and image on UIButton with imageEdgeInsets and titleEdgeInsets

In swift 5.3 and Inspired by @ravron answer:

extension UIButton {
    /// Fits the image and text content with a given spacing
    /// - Parameters:
    ///   - spacing: Spacing between the Image and the text
    ///   - contentXInset: The spacing between the view to the left image and the right text to the view
    func setHorizontalMargins(imageTextSpacing: CGFloat, contentXInset: CGFloat = 0) {
        let imageTextSpacing = imageTextSpacing / 2
        contentEdgeInsets = UIEdgeInsets(top: 0, left: (imageTextSpacing + contentXInset), bottom: 0, right: (imageTextSpacing + contentXInset))
        imageEdgeInsets = UIEdgeInsets(top: 0, left: -imageTextSpacing, bottom: 0, right: imageTextSpacing)
        titleEdgeInsets = UIEdgeInsets(top: 0, left: imageTextSpacing, bottom: 0, right: -imageTextSpacing)

It adds an extra horizontal margin from the View to the Image and from the Label to the View

jQuery selector first td of each row

$('td:first-child') will return a collection of the elements that you want.

var text = $('td:first-child').map(function() {
  return $(this).html();

How to Correctly handle Weak Self in Swift Blocks with Arguments

As of swift 4.2 we can do:

_ = { [weak self] value in
    guard let self = self else { return }
    print(self) // will never be nil

Performing a query on a result from another query?

I don't know if you even need to wrap it. Won't this work?

SELECT COUNT(*), SUM(DATEDIFF(now(),availables.updated_at))
FROM availables
INNER JOIN rooms    ON
WHERE availables.bookdate BETWEEN '2009-06-25' 
  AND date_add('2009-06-25', INTERVAL 4 DAY)
  AND rooms.hostel_id = 5094
GROUP BY availables.bookdate);

If your goal is to return both result sets then you'll need to store it some place temporarily.

Sending HTML Code Through JSON

Do Like this

1st put all your HTML content to array, then do json_encode

$html_content="<p>hello this is sample text";

echo json_encode($json_array);

How can I disable a button in a jQuery dialog from a function?

Here's an example that I just implemented using the Array method of assigning buttons, which then allows me to use id selectors later on - just as the accepted answer stated originally - to enable/disable buttons and even show/hide them completely as I'm doing.

$( "#dialog-form" ).dialog({
autoOpen: true,
height: 500,
width: 450,
modal: true,
buttons: [
    id: "submit_btn",
    text: "Make Apointment",
    click: function() { 
        //do ajax       
    id: "cancel_btn",
    text: "Cancel",
    click: function() {
       $( this ).dialog( "close" );
    id: "ok_btn",
    text: "OK",
    click: function() {
       $( this).dialog('close');
    disabled: "disabled"
close: function() {
    allFields.val( "" ).removeClass( "ui-state-error" );

After successfully submitting, I disable and hide two of the buttons and enable the OK button that was disabled by default.

$('#submit_btn, #cancel_btn').attr('disabled','disabled').addClass('ui-state-disabled').hide();

Hope this helps.

Finding what methods a Python object has

Take a list as an object

obj = []

list(filter(lambda x:callable(getattr(obj,x)),obj.__dir__()))

You get:


Alternate output format for psql

(New) Expanded Auto Mode: \x auto

New for Postgresql 9.2; PSQL automatically fits records to the width of the screen. previously you only had expanded mode on or off and had to switch between the modes as necessary.

  • If the record can fit into the width of the screen; psql uses normal formatting.
  • If the record can not fit into the width of the screen; psql uses expanded mode.

To get this use: \x auto

Postgresql 9.5 Documentation on PSQL command.

Wide screen, normal formatting:

 id | time  |       humanize_time             | value 
  1 | 09:30 |  Early Morning - (9.30 am)      |   570
  2 | 11:30 |  Late Morning - (11.30 am)      |   690
  3 | 13:30 |  Early Afternoon - (1.30pm)     |   810
  4 | 15:30 |  Late Afternoon - (3.30 pm)     |   930
(4 rows)

Narrow screen, expanded formatting:

-[ RECORD 1 ]-+---------------------------
id            | 1
time          | 09:30
humanize_time | Early Morning - (9.30 am)
value         | 570
-[ RECORD 2 ]-+---------------------------
id            | 2
time          | 11:30
humanize_time | Late Morning - (11.30 am)
value         | 690
-[ RECORD 3 ]-+---------------------------
id            | 3
time          | 13:30
humanize_time | Early Afternoon - (1.30pm)
value         | 810
-[ RECORD 4 ]-+---------------------------
id            | 4
time          | 15:30
humanize_time | Late Afternoon - (3.30 pm)
value         | 930

How to start psql with \x auto?

Configure \x auto command on startup by adding it to .psqlrc in your home folder and restarting psql. Look under 'Files' section in the psql doc for more info.


\x auto

How to make the 'cut' command treat same sequental delimiters as one?

With versions of cut I know of, no, this is not possible. cut is primarily useful for parsing files where the separator is not whitespace (for example /etc/passwd) and that have a fixed number of fields. Two separators in a row mean an empty field, and that goes for whitespace too.

Why am I getting "undefined reference to sqrt" error even though I include math.h header?

The math library must be linked in when building the executable. How to do this varies by environment, but in Linux/Unix, just add -lm to the command:

gcc test.c -o test -lm

The math library is named, and the -l command option assumes a lib prefix and .a or .so suffix.

Using SHA1 and RSA with vs. MessageDigest and Cipher

I have a similar problem, I tested adding code and found some interesting results. With this code I add, I can deduce that depending on the "provider" to use, the firm can be different? (because the data included in the encryption is not always equal in all providers).

Results of my test.

Conclusion.- Signature Decipher= ???(trash) + DigestInfo (if we know the value of "trash", the digital signatures will be equal)

IDE Eclipse OUTPUT...

Input data: This is the message being signed

Digest: 62b0a9ef15461c82766fb5bdaae9edbe4ac2e067

DigestInfo: 3021300906052b0e03021a0500041462b0a9ef15461c82766fb5bdaae9edbe4ac2e067

Signature Decipher: 1ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff003021300906052b0e03021a0500041462b0a9ef15461c82766fb5bdaae9edbe4ac2e067


import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import org.bouncycastle.asn1.x509.DigestInfo;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
public class prueba {
* @param args
* @throws NoSuchProviderException 
* @throws NoSuchAlgorithmException 
* @throws InvalidKeyException 
* @throws SignatureException 
* @throws NoSuchPaddingException 
* @throws BadPaddingException 
* @throws IllegalBlockSizeException 
public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchProviderException, InvalidKeyException, SignatureException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
// TODO Auto-generated method stub
KeyPair keyPair = KeyPairGenerator.getInstance("RSA","BC").generateKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
PublicKey puKey = keyPair.getPublic();
String plaintext = "This is the message being signed";
// Hacer la firma
Signature instance = Signature.getInstance("SHA1withRSA","BC");
byte[] signature = instance.sign();
// En dos partes primero hago un Hash
MessageDigest digest = MessageDigest.getInstance("SHA1", "BC");
byte[] hash = digest.digest((plaintext).getBytes());
// El digest es identico a  openssl dgst -sha1 texto.txt
//MessageDigest sha1 = MessageDigest.getInstance("SHA1","BC");
//byte[] digest = sha1.digest((plaintext).getBytes());
AlgorithmIdentifier digestAlgorithm = new AlgorithmIdentifier(new
DERObjectIdentifier(""), null);
// create the digest info
DigestInfo di = new DigestInfo(digestAlgorithm, hash);
byte[] digestInfo = di.getDEREncoded();
//Luego cifro el hash
Cipher cipher = Cipher.getInstance("RSA","BC");
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] cipherText = cipher.doFinal(digestInfo);
//byte[] cipherText = cipher.doFinal(digest2);
Cipher cipher2 = Cipher.getInstance("RSA","BC");
cipher2.init(Cipher.DECRYPT_MODE, puKey);
byte[] cipherText2 = cipher2.doFinal(signature);
System.out.println("Input data: " + plaintext);
System.out.println("Digest: " + bytes2String(hash));
System.out.println("Signature: " + bytes2String(signature));
System.out.println("Signature2: " + bytes2String(cipherText));
System.out.println("DigestInfo: " + bytes2String(digestInfo));
System.out.println("Signature Decipher: " + bytes2String(cipherText2));

How can I insert into a BLOB column from an insert statement in sqldeveloper?

  1. insert into mytable(id, myblob) values (1,EMPTY_BLOB);
  2. SELECT * FROM mytable mt where for update
  3. Click on the Lock icon to unlock for editing
  4. Click on the ... next to the BLOB to edit
  5. Select the appropriate tab and click open on the top left.
  6. Click OK and commit the changes.

How to check if a variable is both null and /or undefined in JavaScript

You can wrap it in your own function:

function isNullAndUndef(variable) {

    return (variable !== null && variable !== undefined);

Windows Batch Files: if else

Another related tip is to use "%~1" instead of "%1". Type "CALL /?" at the command line in Windows to get more details.

The located assembly's manifest definition does not match the assembly reference

I had similar problem but no answer worked for me.

The solution that worked for me was removing publicKeyToken part from project file(YourProject.csproj) manually.

Previously it had been:

<Reference Include="Utility, Version=, Culture=neutral, PublicKeyToken=e71b9933bfee3534, processorArchitecture=MSIL">

After change it was:

<Reference Include="Utility, Version=, Culture=neutral, processorArchitecture=MSIL">

Be sure that SpecificVersion is False.

How do you decompile a swf file

Usually 'lost' is a euphemism for "We stopped paying the developer and now he wont give us the source code."

That being said, I own a copy of Burak's ActionScript Viewer, and it works pretty well. A simple google search will find you many other SWF decompilers.

Python MYSQL update statement

It should be:

cursor.execute ("""
   UPDATE tblTableName
   SET Year=%s, Month=%s, Day=%s, Hour=%s, Minute=%s
   WHERE Server=%s
""", (Year, Month, Day, Hour, Minute, ServerID))

You can also do it with basic string manipulation,

cursor.execute ("UPDATE tblTableName SET Year=%s, Month=%s, Day=%s, Hour=%s, Minute=%s WHERE Server='%s' " % (Year, Month, Day, Hour, Minute, ServerID))

but this way is discouraged because it leaves you open for SQL Injection. As it's so easy (and similar) to do it the right waytm. Do it correctly.

The only thing you should be careful, is that some database backends don't follow the same convention for string replacement (SQLite comes to mind).

Disable/Enable Submit Button until all forms have been filled

Just use

document.getElementById('submitbutton').disabled = !cansubmit;

instead of the the if-clause that works only one-way.

Also, for the users who have JS disabled, I'd suggest to set the initial disabled by JS only. To do so, just move the script behind the <form> and call checkform(); once.

Drawing in Java using Canvas

Why would the first way not work. Canvas object is created and the size is set and the grahpics are set. I always find this strange. Also if a class extends JComponent you can override the


and then shouldn't you be able to create and instance of the class inside of another class and then just call NewlycreateinstanceOfAnyClass.repaint();

I have tried this approach for some game programming I have been working and it doesn't seem to work the way I think that it should be.

Doug Hauf

How to make a <ul> display in a horizontal row

You could also set them to float to the right.

#ul_top_hypers li {
    float: right;

This allows them to still be block level, but will appear on the same line.

What is the meaning of "int(a[::-1])" in Python?

The notation that is used in


means that for a given string/list/tuple, you can slice the said object using the format

<object_name>[<start_index>, <stop_index>, <step>]

This means that the object is going to slice every "step" index from the given start index, till the stop index (excluding the stop index) and return it to you.

In case the start index or stop index is missing, it takes up the default value as the start index and stop index of the given string/list/tuple. If the step is left blank, then it takes the default value of 1 i.e it goes through each index.


a = '1234'
print a[::2]

would print


Now the indexing here and also the step count, support negative numbers. So, if you give a -1 index, it translates to len(a)-1 index. And if you give -x as the step count, then it would step every x'th value from the start index, till the stop index in the reverse direction. For example

a = '1234'
print a[3:0:-1]

This would return


Note, that it doesn't return 4321 because, the stop index is not included.

Now in your case,


would just reverse a given integer, that is stored in a string, and then convert it back to a string

i.e "1234" -> "4321" -> 4321 -> "4321"

If what you are trying to do is just reverse the given string, then simply a[::-1] would work .

How Do I Take a Screen Shot of a UIView?

you can use following UIView category -

@implementation UIView (SnapShot)

 - (UIImage *)snapshotImage
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, [UIScreen mainScreen].scale);        
    [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:NO];        
    // old style [self.layer renderInContext:UIGraphicsGetCurrentContext()];        
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();        
    return image;

Labeling file upload button

It is normally provided by the browser and hard to change, so the only way around it will be a CSS/JavaScript hack,

See the following links for some approaches:

Where's the IE7/8/9/10-emulator in IE11 dev tools?

I posted an answer to this already when someone else asked the same question (see How to bring back "Browser mode" in IE11?).

Read my answer there for a fuller explaination, but in short:

  • They removed it deliberately, because compat mode is not actually really very good for testing compatibility.

  • If you really want to test for compatibility with any given version of IE, you need to test in a real copy of that IE version. MS provide free VMs on for you to use for this purpose.

  • The only way to get compat mode in IE11 is to set the X-UA-Compatible header. When you have this and the site defaults to compat mode, you will be able to set the mode in dev tools, but only between edge or the specified compat mode; other modes will still not be available.

Postgresql : Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections

The error you quote has nothing to do with pg_hba.conf; it's failing to connect, not failing to authorize the connection.

Do what the error message says:

Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections

You haven't shown the command that produces the error. Assuming you're connecting on localhost port 5432 (the defaults for a standard PostgreSQL install), then either:

  • PostgreSQL isn't running

  • PostgreSQL isn't listening for TCP/IP connections (listen_addresses in postgresql.conf)

  • PostgreSQL is only listening on IPv4 ( or and you're connecting on IPv6 (::1) or vice versa. This seems to be an issue on some older Mac OS X versions that have weird IPv6 socket behaviour, and on some older Windows versions.

  • PostgreSQL is listening on a different port to the one you're connecting on

  • (unlikely) there's an iptables rule blocking loopback connections

(If you are not connecting on localhost, it may also be a network firewall that's blocking TCP/IP connections, but I'm guessing you're using the defaults since you didn't say).

So ... check those:

  • ps -f -u postgres should list postgres processes

  • sudo lsof -n -u postgres |grep LISTEN or sudo netstat -ltnp | grep postgres should show the TCP/IP addresses and ports PostgreSQL is listening on

BTW, I think you must be on an old version. On my 9.3 install, the error is rather more detailed:

$ psql -h localhost -p 12345
psql: could not connect to server: Connection refused
        Is the server running on host "localhost" (::1) and accepting
        TCP/IP connections on port 12345?

pandas get column average/mean

you can use


you will get basic statistics of the dataframe and to get mean of specific column you can use


What is "Linting"?

Interpreted languages like Python and JavaScript benefit greatly from linting, as these languages don’t have a compiling phase to display errors before execution.

Linters are also useful for code formatting and/or adhering to language specific best practices.

Lately I have been using ESLint for JS/React and will occasionally use it with an airbnb-config file.

How can Bash execute a command in a different directory context?

(cd /path/to/your/special/place;/bin/your-special-command ARGS)

Get an element by index in jQuery

You could skip the jquery and just use CSS style tagging:

 <li style="background-color:#343434;">China</li>
 <li>United States</li>
 <li>United Kingdom</li>

Can I execute a function after setState is finished updating?

Making setState return a Promise

In addition to passing a callback to setState() method, you can wrap it around an async function and use the then() method -- which in some cases might produce a cleaner code:

(async () => new Promise(resolve => this.setState({dummy: true}), resolve)()
    .then(() => { console.log('state:', this.state) });

And here you can take this one more step ahead and make a reusable setState function that in my opinion is better than the above version:

const promiseState = async state =>
    new Promise(resolve => this.setState(state, resolve));

    .then(() => promiseState({...})
    .then(() => {
        ...  // other code
        return promiseState({...});
    .then(() => {...});

This works fine in React 16.4, but I haven't tested it in earlier versions of React yet.

Also worth mentioning that keeping your callback code in componentDidUpdate method is a better practice in most -- probably all, cases.

Disabling the long-running-script message in Internet Explorer

This message displays when Internet Explorer reaches the maximum number of synchronous instructions for a piece of JavaScript. The default maximum is 5,000,000 instructions, you can increase this number on a single machine by editing the registry.

Internet Explorer now tracks the total number of executed script statements and resets the value each time that a new script execution is started, such as from a timeout or from an event handler, for the current page with the script engine. Internet Explorer displays a "long-running script" dialog box when that value is over a threshold amount.

The only way to solve the problem for all users that might be viewing your page is to break up the number of iterations your loop performs using timers, or refactor your code so that it doesn't need to process as many instructions.

Breaking up a loop with timers is relatively straightforward:

var i=0;
(function () {
    for (; i < 6000000; i++) {
            Normal processing here

        // Every 100,000 iterations, take a break
        if ( i > 0 && i % 100000 == 0) {
            // Manually increment `i` because we break
            // Set a timer for the next iteration 

How do I fix a "Performance counter registry hive consistency" when installing SQL Server R2 Express?

Use Rafael's solution:

Added data from link to avoid link rot..

put this at any Console application:

string.Format("{0,3}", CultureInfo.InstalledUICulture.Parent.LCID.ToString("X")).Replace(" ", "0");

Watch the result. At mine it was "016".

Then you go to the registry at this key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib

and create another one with the name you got from the string.Format result.

In my case:

"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib\016"

and copy the info that is on any other key in this Perflib to this key you just created. Run the instalation again.

Just run the script and get your 3 digit code. Then follow his simple and quick steps, and you're ready to go!


Hiding a password in a python script (insecure obfuscation only)

Why not have a simple xor?


  • looks like binary data
  • noone can read it without knowing the key (even if it's a single char)

I get to the point where I recognize simple b64 strings for common words and rot13 as well. Xor would make it much harder.

Is there any sed like utility for cmd.exe?

There is Super Sed an enhanced version of sed. For Windows this is a standalone .exe, intended for running from the command line.

Create an enum with string values


enum e{
    hello = 1,
    somestr = 'world'

alert(e[1] + ' ' + e.somestr);

TypeScript Playground

Ambiguous overload call to abs(double)

Use fabs() instead of abs(), it's the same but for floats instead of integers.

Loading scripts after page load?

So, there's no way that this works:

window.onload = function(){
  <script language="JavaScript" src=""></script>

You can't freely drop HTML into the middle of javascript.

If you have jQuery, you can just use:


whenever you want. If you want to make sure the document has finished loading, you can do this:

$(document).ready(function() {

In plain javascript, you can load a script dynamically at any time you want to like this:

var tag = document.createElement("script");
tag.src = "";

How to create a new object instance from a Type

I can across this question because I was looking to implement a simple CloneObject method for arbitrary class (with a default constructor)

With generic method you can require that the type implements New().

Public Function CloneObject(Of T As New)(ByVal src As T) As T
    Dim result As T = Nothing
    Dim cloneable = TryCast(src, ICloneable)
    If cloneable IsNot Nothing Then
        result = cloneable.Clone()
        result = New T
        CopySimpleProperties(src, result, Nothing, "clone")
    End If
    Return result
End Function

With non-generic assume the type has a default constructor and catch an exception if it doesn't.

Public Function CloneObject(ByVal src As Object) As Object
    Dim result As Object = Nothing
    Dim cloneable As ICloneable
        cloneable = TryCast(src, ICloneable)
        If cloneable IsNot Nothing Then
            result = cloneable.Clone()
            result = Activator.CreateInstance(src.GetType())
            CopySimpleProperties(src, result, Nothing, "clone")
        End If
    Catch ex As Exception
        Trace.WriteLine("!!! CloneObject(): " & ex.Message)
    End Try
    Return result
End Function

Java 8 - Best way to transform a list: map or foreach?

Don't worry about any performance differences, they're going to be minimal in this case normally.

Method 2 is preferable because

  1. it doesn't require mutating a collection that exists outside the lambda expression,

  2. it's more readable because the different steps that are performed in the collection pipeline are written sequentially: first a filter operation, then a map operation, then collecting the result (for more info on the benefits of collection pipelines, see Martin Fowler's excellent article),

  3. you can easily change the way values are collected by replacing the Collector that is used. In some cases you may need to write your own Collector, but then the benefit is that you can easily reuse that.

Python assigning multiple variables to same value? list behavior

What you need is this:

a, b, c = [0,3,5] # Unpack the list, now a, b, and c are ints
a = 1             # `a` did equal 0, not [0,3,5]

How do I use the new computeIfAbsent function?

Another example. When building a complex map of maps, the computeIfAbsent() method is a replacement for map's get() method. Through chaining of computeIfAbsent() calls together, missing containers are constructed on-the-fly by provided lambda expressions:

  // Stores regional movie ratings
  Map<String, Map<Integer, Set<String>>> regionalMovieRatings = new TreeMap<>();

  // This will throw NullPointerException!
  regionalMovieRatings.get("New York").get(5).add("Boyhood");

  // This will work
    .computeIfAbsent("New York", region -> new TreeMap<>())
    .computeIfAbsent(5, rating -> new TreeSet<>())

How to return a result (startActivityForResult) from a TabHost Activity?

You could implement a onActivityResult in Class B as well and launch Class C using startActivityForResult. Once you get the result in Class B then set the result there (for Class A) based on the result from Class C. I haven't tried this out but I think this should work.

Another thing to look out for is that Activity A should not be a singleInstance activity. For startActivityForResult to work your Class B needs to be a sub activity to Activity A and that is not possible in a single instance activity, the new Activity (Class B) starts in a new task.

How should I pass an int into stringWithFormat?

Is the snippet you posted just a sample to show what you are trying to do?

The reason I ask is that you've named a method increment, but you seem to be using that to set the value of a text label, rather than incrementing a value.

If you are trying to do something more complicated - such as setting an integer value and having the label display this value, you could consider using bindings. e.g

You declare a property count and your increment action sets this value to whatever, and then in IB, you bind the label's text to the value of count. As long as you follow Key Value Coding (KVC) with count, you don't have to write any code to update the label's display. And from a design perspective you've got looser coupling.

What is the difference between WCF and WPF?

Basically, if you are developing a client- server application. You may use WCF -> in order to make connection between client and server, WPF -> as client side to present the data.

Read lines from a text file but skip the first two lines

You can use random access.

Open "C:\docs\TESTFILE.txt" For Random As #1 

    Position = 3    ' Define record number.
    Get #1, Position, ARecord    ' Read record.

Close #1

VS2010 How to include files in project, to copy them to build output directory automatically during build or publish

I only have the need to push files during a build, so I just added a Post-build Event Command Line entry like this:

Copy /Y "$(SolutionDir)Third Party\SomeLibrary\*" "$(TargetDir)"

You can set this by right-clicking your Project in the Solution Explorer, then Properties > Build Events

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

This eclipse documentation has details on the markups in .project file: The project description file

It describes the .project file as:

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

Python Image Library fails with message "decoder JPEG not available" - PIL

For those on OSX, I used the following binary to get libpng and libjpeg installed systemwide:

libpng & libjpeg for OSX

Because I already had PIL installed (via pip on a virtualenv), I ran:

pip uninstall PIL
pip install PIL --upgrade

This resolved the decoder JPEG not available error for me.

UPDATE (4/24/14):

Newer versions of pip require additional flags to download libraries (including PIL) from external sources. Try the following:

pip install PIL --allow-external PIL --allow-unverified PIL

See the following answer for additional info: pip install PIL dont install into virtualenv


If on OSX Mavericks, you'll want to set the ARCHFLAGS flag as @RicardoGonzales comments below:

ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future pip install PIL --allow-external PIL --allow-unverified PIL

Attach a file from MemoryStream to a MailMessage in C#

If you actually want to add a .pdf, I found it necessary to set the position of the memory stream to Zero.

var memStream = new MemoryStream(yourPdfByteArray);
memStream.Position = 0;
var contentType = new System.Net.Mime.ContentType(System.Net.Mime.MediaTypeNames.Application.Pdf);
var reportAttachment = new Attachment(memStream, contentType);
reportAttachment.ContentDisposition.FileName = "yourFileName.pdf";

Run reg command in cmd (bat file)?

If memory serves correct, the reg add command will NOT create the entire directory path if it does not exist. Meaning that if any of the parent registry keys do not exist then they must be created manually one by one. It is really annoying, I know! Example:

@echo off
reg add "HKCU\Software\Policies"
reg add "HKCU\Software\Policies\Microsoft"
reg add "HKCU\Software\Policies\Microsoft\Internet Explorer"
reg add "HKCU\Software\Policies\Microsoft\Internet Explorer\Control Panel"
reg add "HKCU\Software\Policies\Microsoft\Internet Explorer\Control Panel" /v HomePage /t REG_DWORD /d 1 /f

Forcing label to flow inline with input that they label

Why don't You just use:

label {
    display: block;
    width: 50px;
    height: 24px;
    float: left;

How to set the maximum memory usage for JVM?

The NativeHeap can be increasded by -XX:MaxDirectMemorySize=256M (default is 128)

I've never used it. Maybe you'll find it useful.

Error in <my code> : object of type 'closure' is not subsettable

In case of this similar error Warning: Error in $: object of type 'closure' is not subsettable [No stack trace available]

Just add corresponding package name using :: e.g.

instead of tags(....)

write shiny::tags(....)

How to check whether a string is a valid HTTP URL?

Uri uri = null;
if (!Uri.TryCreate(url, UriKind.Absolute, out uri) || null == uri)
    return false;
    return true;

Here url is the string you have to test.

How do I call a function twice or more times consecutively?

I would:

for _ in range(3):

The _ is convention for a variable whose value you don't care about.

You might also see some people write:

[do() for _ in range(3)]

however that is slightly more expensive because it creates a list containing the return values of each invocation of do() (even if it's None), and then throws away the resulting list. I wouldn't suggest using this unless you are using the list of return values.