Programs & Examples On #Contentproperty

When do I need to use a semicolon vs a slash in Oracle SQL?

From my understanding, all the SQL statement don't need forward slash as they will run automatically at the end of semicolons, including DDL, DML, DCL and TCL statements.

For other PL/SQL blocks, including Procedures, Functions, Packages and Triggers, because they are multiple line programs, Oracle need a way to know when to run the block, so we have to write a forward slash at the end of each block to let Oracle run it.

python pip: force install ignoring dependencies

When I were trying install librosa package with pip (pip install librosa), this error were appeared:

ERROR: Cannot uninstall 'llvmlite'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.

I tried to remove llvmlite, but pip uninstall could not remove it. So, I used capability of ignore of pip by this code:

pip install librosa --ignore-installed llvmlite

Indeed, you can use this rule for ignoring a package you don't want to consider:

pip install {package you want to install} --ignore-installed {installed package you don't want to consider}

Is there a native jQuery function to switch elements?

I have done it with this snippet

// Create comments
var t1 = $('<!-- -->');
var t2 = $('<!-- -->');
// Position comments next to elements
// Move elements
// Remove comments

SQL Server Convert Varchar to Datetime

You could do it this way but it leaves it as a varchar

declare @s varchar(50)

set @s = '2011-09-28 18:01:00'

select convert(varchar, cast(@s as datetime), 105) + RIGHT(@s, 9)


select convert(varchar(20), @s, 105)

How to make a loop in x86 assembly language?

Use the CX register to count the loops

mov cx, 3
   cmp cx, 0
   jz endofloop
   push cx
   Call ClrScr
   pop cx
   dec cx
   jmp startloop
   ; Loop ended
   ; Do what ever you have to do here

This simply loops around 3 times calling ClrScr, pushing the CX register onto the stack, comparing to 0, jumping if ZeroFlag is set then jump to endofloop. Notice how the contents of CX is pushed/popped on/off the stack to maintain the flow of the loop.

How to add a Browse To File dialog to a VB.NET application

You should use the OpenFileDialog class like this

Dim fd As OpenFileDialog = New OpenFileDialog() 
Dim strFileName As String

fd.Title = "Open File Dialog"
fd.InitialDirectory = "C:\"
fd.Filter = "All files (*.*)|*.*|All files (*.*)|*.*"
fd.FilterIndex = 2
fd.RestoreDirectory = True

If fd.ShowDialog() = DialogResult.OK Then
   strFileName = fd.FileName
End If

Then you can use the File class.

Multiple simultaneous downloads using Wget?

A new (but yet not released) tool is Mget. It has already many options known from Wget and comes with a library that allows you to easily embed (recursive) downloading into your own application.

To answer your question:

mget --num-threads=4 [url]


Mget is now developed as Wget2 with many bugs fixed and more features (e.g. HTTP/2 support).

--num-threads is now --max-threads.

Resize command prompt through commands

Although the answers given here can be used to temporarily change window size, they don't seem to affect font size (at least not on my PC). I have an alternative way. I don't know if this what you're looking for but if you want to make changes automatically/permanently to Console font/window size, you can always do a script that edits the registry:


Those keys deal with the consoles that come up when your run a script or press shift and select "open command prompt here". The Command Prompt entry in your start menu does not use the registry to store it's preferences but stores the prefs in the shortcut itself.

I have a monitor that I can run in 720p native or 1440p supersampling. I needed a quick way to change my console's font/window size, so I made these scripts. These scripts do two things: (1) change the font/window sizes in the registry and (2) swap out the shortcuts in the Start menu with ones that have a different window and font size. I basically made two sets of copies of the Command Prompt and Power Shell shortcuts and stored them in Documents. One set of shortcuts was configured with Consolas font size at 16 for my monitor is in 720p (called it "Command Prompt.720pRes.lnk") and another version of the same shortcut was configure with font size at 36 (called it "Command Prompt.HighRes.lnk"). The script will copy from the set I want to use to overwrite the Start menu one.


::Assign New Window and Font Size for Windows Command Prompt
set CMDpNewFont=00240000
set CMDpNewWindowSize=000f0078
set commandPromptLinkFlag=highRes

 ::Make temporary .reg file to resize command console

>%temp%\consoleSIZEchanger.reg ECHO Windows Registry Editor Version 5.00
>>%temp%\consoleSIZEchanger.reg ECHO.
>>%temp%\consoleSIZEchanger.reg ECHO [HKEY_CURRENT_USER\Console]
>>%temp%\consoleSIZEchanger.reg ECHO "WindowSize"=dword:%CMDpNewWindowSize%
>>%temp%\consoleSIZEchanger.reg ECHO "FontSize"=dword:%CMDpNewFont%
>>%temp%\consoleSIZEchanger.reg ECHO.
>>%temp%\consoleSIZEchanger.reg ECHO [HKEY_CURRENT_USER\Console\%%SystemRoot%%_system32_cmd.exe]
>>%temp%\consoleSIZEchanger.reg ECHO "WindowSize"=dword:%CMDpNewWindowSize%
>>%temp%\consoleSIZEchanger.reg ECHO "FontSize"=dword:%CMDpNewFont%
>>%temp%\consoleSIZEchanger.reg ECHO.
>>%temp%\consoleSIZEchanger.reg ECHO [HKEY_CURRENT_USER\Console\%%SystemRoot%%_system32_WindowsPowerShell_v1.0_powershell.exe]
>>%temp%\consoleSIZEchanger.reg ECHO "WindowSize"=dword:%CMDpNewWindowSize%
>>%temp%\consoleSIZEchanger.reg ECHO "FontSize"=dword:%CMDpNewFont%

::Merge and delete consoleSIZEchanger.reg
REGEDIT /S %temp%\consoleSIZEchanger.reg 
del %temp%\consoleSIZEchanger.reg 

::Copy Preconfigured Command Prompt/PowerShell shortcuts to Pinned Start Menu, Accessories and any other Custom Location you would define
copy "%homedrive%%homepath%\Documents\Command Prompt.%commandPromptLinkFlag%.lnk" "%homedrive%%homepath%\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\StartMenu\Command Prompt.lnk"
copy "%homedrive%%homepath%\Documents\Command Prompt.%commandPromptLinkFlag%.lnk" "%homedrive%%homepath%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Accessories\Command Prompt.lnk"
copy "%homedrive%%homepath%\Documents\Windows PowerShell.%commandPromptLinkFlag%.lnk" "%homedrive%\ProgramData\Microsoft\Windows\Start Menu\Programs\Accessories\Windows PowerShell\Windows PowerShell.lnk"
copy "%homedrive%%homepath%\Documents\Windows PowerShell.%commandPromptLinkFlag%.lnk" "%homedrive%%homepath%\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\StartMenu\Windows PowerShell.lnk"                 
copy "%homedrive%%homepath%\Documents\Windows PowerShell (x86).%commandPromptLinkFlag%.lnk" "%homedrive%\ProgramData\Microsoft\Windows\Start Menu\Programs\Accessories\Windows PowerShell\Windows PowerShell (x86).lnk"
copy "%homedrive%%homepath%\Documents\Windows PowerShell (x86).%commandPromptLinkFlag%.lnk" "%homedrive%%homepath%\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\StartMenu\Windows PowerShell (x86).lnk"


::Assign New Window and Font Size for Windows Command Prompt
set CMDpNewFont=00100000
set CMDpNewWindowSize=0014007d
set commandPromptLinkFlag=720Res

 ::Make temporary .reg file to resize command console
>%temp%\consoleSIZEchanger.reg ECHO Windows Registry Editor Version 5.00
>>%temp%\consoleSIZEchanger.reg ECHO.
>>%temp%\consoleSIZEchanger.reg ECHO [HKEY_CURRENT_USER\Console]
>>%temp%\consoleSIZEchanger.reg ECHO "WindowSize"=dword:%CMDpNewWindowSize%
>>%temp%\consoleSIZEchanger.reg ECHO "FontSize"=dword:%CMDpNewFont%
>>%temp%\consoleSIZEchanger.reg ECHO.
>>%temp%\consoleSIZEchanger.reg ECHO [HKEY_CURRENT_USER\Console\%%SystemRoot%%_system32_cmd.exe]
>>%temp%\consoleSIZEchanger.reg ECHO "WindowSize"=dword:%CMDpNewWindowSize%
>>%temp%\consoleSIZEchanger.reg ECHO "FontSize"=dword:%CMDpNewFont%
>>%temp%\consoleSIZEchanger.reg ECHO.
>>%temp%\consoleSIZEchanger.reg ECHO [HKEY_CURRENT_USER\Console\%%SystemRoot%%_system32_WindowsPowerShell_v1.0_powershell.exe]
>>%temp%\consoleSIZEchanger.reg ECHO "WindowSize"=dword:%CMDpNewWindowSize%
>>%temp%\consoleSIZEchanger.reg ECHO "FontSize"=dword:%CMDpNewFont%

::Merge and delete consoleSIZEchanger.reg
REGEDIT /S %temp%\consoleSIZEchanger.reg 
del %temp%\consoleSIZEchanger.reg 

::Copy Preconfigured Command Prompt/PowerShell shortcuts to Pinned Start Menu, Accessories and any other Custom Location you would define
copy "%homedrive%%homepath%\Documents\Command Prompt.%commandPromptLinkFlag%.lnk" "%homedrive%%homepath%\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\StartMenu\Command Prompt.lnk"
copy "%homedrive%%homepath%\Documents\Command Prompt.%commandPromptLinkFlag%.lnk" "%homedrive%%homepath%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Accessories\Command Prompt.lnk"
copy "%homedrive%%homepath%\Documents\Windows PowerShell.%commandPromptLinkFlag%.lnk" "%homedrive%\ProgramData\Microsoft\Windows\Start Menu\Programs\Accessories\Windows PowerShell\Windows PowerShell.lnk"
copy "%homedrive%%homepath%\Documents\Windows PowerShell.%commandPromptLinkFlag%.lnk" "%homedrive%%homepath%\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\StartMenu\Windows PowerShell.lnk"                 
copy "%homedrive%%homepath%\Documents\Windows PowerShell (x86).%commandPromptLinkFlag%.lnk" "%homedrive%\ProgramData\Microsoft\Windows\Start Menu\Programs\Accessories\Windows PowerShell\Windows PowerShell (x86).lnk"
copy "%homedrive%%homepath%\Documents\Windows PowerShell (x86).%commandPromptLinkFlag%.lnk" "%homedrive%%homepath%\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\StartMenu\Windows PowerShell (x86).lnk"

Submit a form using jQuery

IE trick for dynamic forms:


CSS3 transitions inside jQuery .css()

Your code can get messy fast when dealing with CSS3 transitions. I would recommend using a plugin such as jQuery Transit that handles the complexity of CSS3 animations/transitions.

Moreover, the plugin uses webkit-transform rather than webkit-transition, which allows for mobile devices to use hardware acceleration in order to give your web apps that native look and feel when the animations occur.

JS Fiddle Live Demo


$("#startTransition").on("click", function()

    if( $(".boxOne").is(":visible")) 
        $(".boxOne").transition({ x: '-100%', opacity: 0.1 }, function () { $(".boxOne").hide(); });
        $(".boxTwo").css({ x: '100%' });
        $(".boxTwo").show().transition({ x: '0%', opacity: 1.0 });

    $(".boxTwo").transition({ x: '-100%', opacity: 0.1 }, function () { $(".boxTwo").hide(); });
    $(".boxOne").css({ x: '100%' });
    $(".boxOne").show().transition({ x: '0%', opacity: 1.0 });


Most of the hard work of getting cross-browser compatibility is done for you as well and it works like a charm on mobile devices.

Fastest check if row exists in PostgreSQL

INSERT INTO target( userid, rightid, count )
  SELECT userid, rightid, count 
  FROM batch
    SELECT * FROM target t2, batch b2
    WHERE t2.userid = b2.userid
    -- ... other keyfields ...

BTW: if you want the whole batch to fail in case of a duplicate, then (given a primary key constraint)

INSERT INTO target( userid, rightid, count )
SELECT userid, rightid, count 
FROM batch

will do exactly what you want: either it succeeds, or it fails.

How to check if a string in Python is in ASCII?

I found this question while trying determine how to use/encode/decode a string whose encoding I wasn't sure of (and how to escape/convert special characters in that string).

My first step should have been to check the type of the string- I didn't realize there I could get good data about its formatting from type(s). This answer was very helpful and got to the real root of my issues.

If you're getting a rude and persistent

UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 263: ordinal not in range(128)

particularly when you're ENCODING, make sure you're not trying to unicode() a string that already IS unicode- for some terrible reason, you get ascii codec errors. (See also the Python Kitchen recipe, and the Python docs tutorials for better understanding of how terrible this can be.)

Eventually I determined that what I wanted to do was this:

escaped_string = unicode(original_string.encode('ascii','xmlcharrefreplace'))

Also helpful in debugging was setting the default coding in my file to utf-8 (put this at the beginning of your python file):

# -*- coding: utf-8 -*-

That allows you to test special characters ('àéç') without having to use their unicode escapes (u'\xe0\xe9\xe7').

>>> specials='àéç'
>>> specials.decode('latin-1').encode('ascii','xmlcharrefreplace')

MVC Razor Radio Button

                                        <td align="right" style="height:26px;">Is Calender Required?:</td>
                                        <td align="left">
                                            @Html.RadioButton("rdbCalenderRequested", "True", new { id = "rdbCalenderRequested_1" })@:Yes &nbsp;&nbsp;&nbsp; 

                                            @Html.RadioButton("rdbCalenderRequested", "False", new { id = "rdbCalenderRequested_2" }) @:No

                                        <td align="right" style="height:26px;">Is Special Pooja?:</td>
                                        <td align="left">
                                            @Html.RadioButton("rdbPoojaRequested", "True", new { id = "rdbPoojaRequested_1" })@:Yes&nbsp;&nbsp;&nbsp; 

                                            @Html.RadioButton("rdbPoojaRequested", "False", new { id = "rdbPoojaRequested_2" }) @:No

GET parameters in the URL with CodeIgniter

allesklar: That is slightly misleading, as scripts and bots can POST data nearly as easily as sending a normal request. It's not a secret, it's part of HTTP.

How to escape single quotes in MySQL

Use either addslahes() or mysql_real_escape_string().

Proper way to use **kwargs in Python

Here's another approach:

def my_func(arg1, arg2, arg3):
    ... so something ...

kwargs = {'arg1': 'Value One', 'arg2': 'Value Two', 'arg3': 'Value Three'}
# Now you can call the function with kwargs like this:


Webpack how to build production code and how to use it

If you have a lot of duplicate code in your and your, you could use a boolean isProd to activate certain features only in certain situations and only have a single webpack.config.js file.

const isProd = (process.env.NODE_ENV === 'production');

 if (isProd) {
     plugins.push(new AotPlugin({
      "mainPath": "main.ts",
      "hostReplacementPaths": {
        "environments/index.ts": "environments/"
      "exclude": [],
      "tsConfigPath": "src/"
    plugins.push(new UglifyJsPlugin({
      "mangle": {
        "screw_ie8": true
      "compress": {
        "screw_ie8": true,
        "warnings": false
      "sourceMap": false

By the way: The DedupePlugin plugin was removed from Webpack. You should remove it from your configuration.


In addition to my previous answer:

If you want to hide your code for release, try It allows you to:

  • make a release version of your application without sources
  • create a self-extracting archive or installer
  • Make a closed source GUI application
  • Put your assets inside the executable

You can install it with npm install -g enclose

Publish to IIS, setting Environment Variable

Similar to other answers, I wanted to ensure my ASP.NET Core 2.1 environment setting persisted across deployments, but also only applied to the specific site.

According to Microsoft's documentation, it is possible to set the environment variable on the app pool using the following PowerShell command in IIS 10:

$appPoolName = "AppPool"
$envName = "Development"
cd "$env:SystemRoot\system32\inetsrv"
.\appcmd.exe set config -section:system.applicationHost/applicationPools /+"[name='$appPoolName'].environmentVariables.[name='ASPNETCORE_ENVIRONMENT',value='$envName']" /commit:apphost

I unfortunately still have to use IIS 8.5 and thought I was out of luck. However, it is still possible to run a simple PowerShell script to set a site-specific environment variable value for ASPNETCORE_ENVIRONMENT:

Import-Module -Name WebAdministration
$siteName = "Site"
$envName = "Development"
Set-WebConfigurationProperty -PSPath IIS:\ -Location $siteName -Filter /system.webServer/aspNetCore/environmentVariables -Name . -Value @{ Name = 'ASPNETCORE_ENVIRONMENT'; Value = $envName }

Android setOnClickListener method - How does it work?

its an implementation of anonymouse class object creation to give ease of writing less code and to save time

How to add a line to a multiline TextBox?

@Casperah pointed out that i'm thinking about it wrong:

  • A TextBox doesn't have lines
  • it has text
  • that text can be split on the CRLF into lines, if requested
  • but there is no notion of lines

The question then is how to accomplish what i want, rather than what WinForms lets me.

There are subtle bugs in the other given variants:

  • textBox1.AppendText("Hello" + Environment.NewLine);
  • textBox1.AppendText("Hello" + "\r\n");
  • textBox1.Text += "Hello\r\n"
  • textbox1.Text += System.Environment.NewLine + "brown";

They either append or prepend a newline when one (might) not be required.

So, extension helper:

public static class WinFormsExtensions
   public static void AppendLine(this TextBox source, string value)
      if (source.Text.Length==0)
         source.Text = value;

So now:



textBox1.AppendLine(String.Format("Processing file {0}", filename));

Note: Any code is released into the public domain. No attribution required.

jQuery function to open link in new window

$(document).ready(function() {
$('A.BLAH').click(function() {
var NWin =$(this).prop('href'), '', 'height=600,width=1000');
if (window.focus)
return false;

Android Studio Rendering Problems : The following classes could not be found

You have to do two things:

  • be sure to have imported right appcompat-v7 library in your project structure -> dependencies
  • change the theme in the preview window to not an AppCompat theme. Try with Holo.light or Holo.dark for example.

Android ListView selected item stay highlighted

I found the proper way. It's very simple. In resource describe following:


(or you may specify a resource link instead of color value)


listView.setSelector(Drawable selector);
listView.setSelector(int resourceId);
listView.setChoiceMode(int mode);

mode can be one of these: AbsListView.CHOICE_MODE_SINGLE, AbsListView.CHOICE_MODE_MULTIPLE, AbsListView.CHOICE_MODE_NONE (default)

(AbsListView is the abstract ancestor for the ListView class)

P.S. manipulations with onItemClick and changing view background are bankrupt, because a view itself is a temporary object. Hence you must not to track a view.

If our list is long enough, the views associated with scrolled out items will be removed from hierarchy, and will be recreated when those items will shown again (with cached display options, such as background). So, the view we have tracked is now not an actual view of the item, and changing its background does nothing to the actual item view. As a result we have multiple items selected.

Magento Product Attribute Get Value

$orderId = 1; // YOUR ORDER ID_x000D_
$items = $block->getOrderItems($orderId);_x000D_
foreach ($items as $item) {_x000D_
    $options = $item->getProductOptions();        _x000D_
    if (isset($options['options']) && !empty($options['options'])) {        _x000D_
        foreach ($options['options'] as $option) {_x000D_
            echo 'Title: ' . $option['label'] . '<br />';_x000D_
            echo 'ID: ' . $option['option_id'] . '<br />';_x000D_
            echo 'Type: ' . $option['option_type'] . '<br />';_x000D_
            echo 'Value: ' . $option['option_value'] . '<br />' . '<br />';_x000D_

all things you will use to retrieve value product custom option cart order in Magento 2:

How to allow all Network connection types HTTP and HTTPS in Android (9) Pie?

A simple way is set android:usesCleartextTraffic="true" on you AndroidManifest.xml


Your AndroidManifest.xml look like

<?xml version="1.0" encoding="utf-8"?>
<manifest package="com.dww.drmanar">
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />

I hope this will help you.

How to convert image to byte array

This is Code for converting the image of any type(for example PNG, JPG, JPEG) to byte array

   public static byte[] imageConversion(string imageName){            

        //Initialize a file stream to read the image file
        FileStream fs = new FileStream(imageName, FileMode.Open, FileAccess.Read);

        //Initialize a byte array with size of stream
        byte[] imgByteArr = new byte[fs.Length];

        //Read data from the file stream and put into the byte array
        fs.Read(imgByteArr, 0, Convert.ToInt32(fs.Length));

        //Close a file stream

        return imageByteArr

You must add a reference to assembly 'netstandard, Version=

You can add to your web.config in your project.

It wouldn't work when you add it to projects web.config because it works with MVC.

Unresolved external symbol in object files

I've just had the same error and I manage to avoid it by replacing ; with {} in the header file.

#ifndef XYZ_h
#define XYZ_h
class XYZ
    void xyzMethod(){}

When it was void xyzMethod(); it didn't want to compile.

Print a variable in hexadecimal in Python

Convert the string to an integer base 16 then to hexadecimal.

print hex(int(string, base=16))

These are built-in functions.


>>> string = 'AA'
>>> _int = int(string, base=16)
>>> _hex = hex(_int)
>>> print _int
>>> print _hex

Get form data in ReactJS

An alternative approach is to use the ref attribute and reference the values with this.refs. Here is a simple example:

render: function() {
    return (<form onSubmit={this.submitForm}>
        <input ref="theInput" />
submitForm: function(e) {

More info can be found in the React docs:

For a lot of the reasons described in How do I use radio buttons in React? this approach isn't always the best, but it does present a useful alternative in some simple cases.

Scheduling recurring task in Android

I realize this is an old question and has been answered but this could help someone. In your activity

private ScheduledExecutorService scheduleTaskExecutor;

In onCreate

  scheduleTaskExecutor = Executors.newScheduledThreadPool(5);

    //Schedule a task to run every 5 seconds (or however long you want)
    scheduleTaskExecutor.scheduleAtFixedRate(new Runnable() {
        public void run() {
            // Do stuff here!

            runOnUiThread(new Runnable() {
                public void run() {
                    // Do stuff to update UI here!
                    Toast.makeText(MainActivity.this, "Its been 5 seconds", Toast.LENGTH_SHORT).show();

    }, 0, 5, TimeUnit.SECONDS); // or .MINUTES, .HOURS etc.

undefined offset PHP error

How to reproduce this error in PHP:

Create an empty array and ask for the value given a key like this:

php> $foobar = array();

php> echo gettype($foobar);

php> echo $foobar[0];

PHP Notice:  Undefined offset: 0 in 
/usr/local/lib/python2.7/dist-packages/phpsh/phpsh.php(578) : 
eval()'d code on line 1

What happened?

You asked an array to give you the value given a key that it does not contain. It will give you the value NULL then put the above error in the errorlog.

It looked for your key in the array, and found undefined.

How to make the error not happen?

Ask if the key exists first before you go asking for its value.

php> echo array_key_exists(0, $foobar) == false;

If the key exists, then get the value, if it doesn't exist, no need to query for its value.

How can I select all rows with sqlalchemy?

I use the following snippet to view all the rows in a table. Use a query to find all the rows. The returned objects are the class instances. They can be used to view/edit the values as required:

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine, Sequence
from sqlalchemy import String, Integer, Float, Boolean, Column
from sqlalchemy.orm import sessionmaker

Base = declarative_base()

class MyTable(Base):
    __tablename__ = 'MyTable'
    id = Column(Integer, Sequence('user_id_seq'), primary_key=True)
    some_col = Column(String(500))

    def __init__(self, some_col):
        self.some_col = some_col

engine = create_engine('sqlite:///sqllight.db', echo=True)
Session = sessionmaker(bind=engine)
session = Session()

for class_instance in session.query(MyTable).all():


Byte Array in Python

An alternative that also has the added benefit of easily logging its output:

hexs = "13 00 00 00 08 00"
key = bytearray.fromhex(hexs)

allows you to do easy substitutions like so:

hexs = "13 00 00 00 08 {:02X}".format(someByte)
key = bytearray.fromhex(hexs)

How to inflate one view with a layout

I had used below snippet of code for this and it worked for me.

LinearLayout linearLayout = (LinearLayout)findViewById(;
View child = getLayoutInflater().inflate(R.layout.child, null);

What's the common practice for enums in Python?

I have no idea why Enums are not support natively by Python. The best way I've found to emulate them is by overridding _ str _ and _ eq _ so you can compare them and when you use print() you get the string instead of the numerical value.

class enumSeason():
    Spring = 0
    Summer = 1
    Fall = 2
    Winter = 3
    def __init__(self, Type):
        self.value = Type
    def __str__(self):
        if self.value == enumSeason.Spring:
            return 'Spring'
        if self.value == enumSeason.Summer:
            return 'Summer'
        if self.value == enumSeason.Fall:
            return 'Fall'
        if self.value == enumSeason.Winter:
            return 'Winter'
    def __eq__(self,y):
       return self.value==y.value


>>> s = enumSeason(enumSeason.Spring)

>>> print(s)


How to get value of checked item from CheckedListBox?

You can iterate over the CheckedItems property:

foreach(object itemChecked in checkedListBox1.CheckedItems)
    MyCompanyClass company = (MyCompanyClass)itemChecked;    
    MessageBox.Show("ID: \"" + company.ID.ToString());

FPDF utf-8 encoding (HOW-TO)

This answer didn't work for me, I needed to run html decode on the string also. See

iconv('UTF-8', 'windows-1252', html_entity_decode($str));

Props go to emfi from html_entity_decode in FPDF(using tFPDF extention)

Converting JSON to XML in Java

Underscore-java library has static method U.jsonToXml(jsonstring). I am the maintainer of the project. Live example

import com.github.underscore.lodash.U;

public class MyClass {
    public static void main(String args[]) {
        String json = "{\"name\":\"JSON\",\"integer\":1,\"double\":2.0,\"boolean\":true,\"nested\":{\"id\":42},\"array\":[1,2,3]}";  
        String xml = U.jsonToXml(json);  


<?xml version="1.0" encoding="UTF-8"?>
  <integer number="true">1</integer>
  <double number="true">2.0</double>
  <boolean boolean="true">true</boolean>
    <id number="true">42</id>
  <array number="true">1</array>
  <array number="true">2</array>
  <array number="true">3</array>

How to center buttons in Twitter Bootstrap 3?

I tried the following code and it worked for me.

<button class="btn btn-default center-block" type="submit">Button</button>

The button control is in a div and using center-block class of bootstrap helped me to align the button to the center of div

Check the link where you will find the center-block class

Python loop that also accesses previous and next values

Two simple solutions:

  1. If variables for both previous and next values have to be defined:
alist = ['Zero', 'One', 'Two', 'Three', 'Four', 'Five']

prev = alist[0]
curr = alist[1]

for nxt in alist[2:]:
    print(f'prev: {prev}, curr: {curr}, next: {nxt}')
    prev = curr
    curr = nxt

prev: Zero, curr: One, next: Two
prev: One, curr: Two, next: Three
prev: Two, curr: Three, next: Four
prev: Three, curr: Four, next: Five
  1. If all values in the list have to be traversed by the current value variable:
alist = ['Zero', 'One', 'Two', 'Three', 'Four', 'Five']

prev = None
curr = alist[0]

for nxt in alist[1:] + [None]:
    print(f'prev: {prev}, curr: {curr}, next: {nxt}')
    prev = curr
    curr = nxt

prev: None, curr: Zero, next: One
prev: Zero, curr: One, next: Two
prev: One, curr: Two, next: Three
prev: Two, curr: Three, next: Four
prev: Three, curr: Four, next: Five
prev: Four, curr: Five, next: None

What can cause intermittent ORA-12519 (TNS: no appropriate handler found) errors

I had this problem in a unit test which opened a lot of connections to the DB via a connection pool and then "stopped" the connection pool (ManagedDataSource actually) to release the connections at the end of the each test. I always ran out of connections at some point in the suite of tests.

Added a Thread.sleep(500) in the teardown() of my tests and this resolved the issue. I think that what was happening was that the connection pool stop() releases the active connections in another thread so that if the main thread keeps running tests the cleanup thread(s) got so far behind that the Oracle server ran out of connections. Adding the sleep allows the background threads to release the pooled connections.

This is much less of an issue in the real world because the DB servers are much bigger and there is a healthy mix of operations (not just endless DB connect/disconnect operations).

How to write an inline IF statement in JavaScript?

You can also approximate an if/else using only Logical Operators.

(a && b) || c

The above is roughly the same as saying:

a ? b : c

And of course, roughly the same as:

if ( a ) { b } else { c }

I say roughly because there is one difference with this approach, in that you have to know that the value of b will evaluate as true, otherwise you will always get c. Bascially you have to realise that the part that would appear if () { here } is now part of the condition that you place if ( here ) { }.

The above is possible due to JavaScripts behaviour of passing / returning one of the original values that formed the logical expression, which one depends on the type of operator. Certain other languages, like PHP, carry on the actual result of the operation i.e. true or false, meaning the result is always true or false; e.g:

14 && 0          /// results as 0,  not false
14 || 0          /// results as 14, not true
1 && 2 && 3 && 4 /// results as 4,  not true
true && ''       /// results as ''
{} || '0'        /// results as {}

One main benefit, compared with a normal if statement, is that the first two methods can operate on the righthand-side of an argument i.e. as part of an assignment.

d = (a && b) || c;
d = a ? b : c;

if `a == true` then `d = b` else `d = c`

The only way to achieve this with a standard if statement would be to duplicate the assigment:

if ( a ) { d = b } else { d = c }

You may ask why use just Logical Operators instead of the Ternary Operator, for simple cases you probably wouldn't, unless you wanted to make sure a and b were both true. You can also achieve more streamlined complex conditions with the Logical operators, which can get quite messy using nested ternary operations... then again if you want your code to be easily readable, neither are really that intuative.

get the titles of all open windows

Here’s some code you can use to get a list of all the open windows. Actually, you get a dictionary where each item is a KeyValuePair where the key is the handle (hWnd) of the window and the value is its title. It also finds pop-up windows, such as those created by MessageBox.Show.

using System.Runtime.InteropServices;
using HWND = System.IntPtr;

/// <summary>Contains functionality to get all the open windows.</summary>
public static class OpenWindowGetter
  /// <summary>Returns a dictionary that contains the handle and title of all the open windows.</summary>
  /// <returns>A dictionary that contains the handle and title of all the open windows.</returns>
  public static IDictionary<HWND, string> GetOpenWindows()
    HWND shellWindow = GetShellWindow();
    Dictionary<HWND, string> windows = new Dictionary<HWND, string>();

    EnumWindows(delegate(HWND hWnd, int lParam)
      if (hWnd == shellWindow) return true;
      if (!IsWindowVisible(hWnd)) return true;

      int length = GetWindowTextLength(hWnd);
      if (length == 0) return true;

      StringBuilder builder = new StringBuilder(length);
      GetWindowText(hWnd, builder, length + 1);

      windows[hWnd] = builder.ToString();
      return true;

    }, 0);

    return windows;

  private delegate bool EnumWindowsProc(HWND hWnd, int lParam);

  private static extern bool EnumWindows(EnumWindowsProc enumFunc, int lParam);

  private static extern int GetWindowText(HWND hWnd, StringBuilder lpString, int nMaxCount);

  private static extern int GetWindowTextLength(HWND hWnd);

  private static extern bool IsWindowVisible(HWND hWnd);

  private static extern IntPtr GetShellWindow();

And here’s some code that uses it:

foreach(KeyValuePair<IntPtr, string> window in OpenWindowGetter.GetOpenWindows())
  IntPtr handle = window.Key;
  string title = window.Value;

  Console.WriteLine("{0}: {1}", handle, title);


PHP Warning: mysqli_connect(): (HY000/2002): Connection refused

In my case I was using XAMPP, and there was a log that told me the error. To find it, go to the XAMPP control panel, and click "Configure" for MySQL, then click on "Open Log."

The most current data of the log is at the bottom, and the log is organized by date, time, some number, and text in brackets that may say "Note" or "Error." One that says "Error" is likely causing the issue.

For me, my error was a tablespace that was causing an issue, so I deleted the database files at the given location.

Note: The tablespace files for your installation of XAMPP may be at a different location, but they were in /opt/lampp/var/mysql for me. I think that's typical of XAMPP on Debian-based distributions. Also, my instructions on what to click in the control panel to see the log may be a bit different for you because I'm running XAMPP on an Ubuntu-based distribution of Linux (Feren OS).

Hide horizontal scrollbar on an iframe?

If you are allowed to change the code of the document inside your iframe and that content is visible only using its parent window, simply add the following CSS in your iframe:

body {

Here a very simple example:

This solution allow you to:

  • Keep you HTML5 valid as it does not need scrolling="no" attribute on the iframe (this attribute in HTML5 has been deprecated).

  • Works on the majority of browsers using CSS overflow:hidden

  • No JS or jQuery necessary.


To disallow scroll-bars horizontally, use this CSS instead:

overflow-x: hidden;

jQuery get the image src

When dealing with the HTML DOM (ie. this), the array selector [0] must be used to retrieve the jQuery element from the Javascript array.



This type of query worked for me:{$group: {_id : "$date", number:  { $sum : 1} }} )


Meaning of "[: too many arguments" error from if [] (square brackets)

Just bumped into this post, by getting the same error, trying to test if two variables are both empty (or non-empty). That turns out to be a compound comparison - 7.3. Other Comparison Operators - Advanced Bash-Scripting Guide; and I thought I should note the following:

  • I used -e thinking it means "empty" at first; but that means "file exists" - use -z for testing empty variable (string)
  • String variables need to be quoted
  • For compound logical AND comparison, either:
    • use two tests and && them: [ ... ] && [ ... ]
    • or use the -a operator in a single test: [ ... -a ... ]

Here is a working command (searching through all txt files in a directory, and dumping those that grep finds contain both of two words):

find /usr/share/doc -name '*.txt' | while read file; do \
  a1=$(grep -H "description" $file); \
  a2=$(grep -H "changes" $file); \
  [ ! -z "$a1" -a ! -z "$a2"  ] && echo -e "$a1 \n $a2" ; \

Edit 12 Aug 2013: related problem note:

Note that when checking string equality with classic test (single square bracket [), you MUST have a space between the "is equal" operator, which in this case is a single "equals" = sign (although two equals' signs == seem to be accepted as equality operator too). Thus, this fails (silently):

$ if [ "1"=="" ] ; then echo A; else echo B; fi 
$ if [ "1"="" ] ; then echo A; else echo B; fi 
$ if [ "1"="" ] && [ "1"="1" ] ; then echo A; else echo B; fi 
$ if [ "1"=="" ] && [ "1"=="1" ] ; then echo A; else echo B; fi 

... but add the space - and all looks good:

$ if [ "1" = "" ] ; then echo A; else echo B; fi 
$ if [ "1" == "" ] ; then echo A; else echo B; fi 
$ if [ "1" = "" -a "1" = "1" ] ; then echo A; else echo B; fi 
$ if [ "1" == "" -a "1" == "1" ] ; then echo A; else echo B; fi 

How to get all privileges back to the root user in MySQL?

If you facing grant permission access denied problem, you can try mysql to fix the problem:

grant all privileges on . to root@'localhost' identified by 'Your password';

grant all privileges on . to root@'IP ADDRESS' identified by 'Your password?';

your can try this on any mysql user, its working.

Use below command to login mysql with iP address.

mysql -h -u root -p

VBA - If a cell in column A is not blank the column B equals

If you really want a vba solution you can loop through a range like this:

Sub Check()
    Dim dat As Variant
    Dim rng As Range
    Dim i As Long

    Set rng = Range("A1:A100")
    dat = rng
    For i = LBound(dat, 1) To UBound(dat, 1)
        If dat(i, 1) <> "" Then
            rng(i, 2).Value = "My Text"
        End If
End Sub


Instead of using varients you can just loop through the range like this:

Sub Check()
    Dim rng As Range
    Dim i As Long

    'Set the range in column A you want to loop through
    Set rng = Range("A1:A100")
    For Each cell In rng
        'test if cell is empty
        If cell.Value <> "" Then
            'write to adjacent cell
            cell.Offset(0, 1).Value = "My Text"
        End If
End Sub

Resizing image in Java

If you have an java.awt.Image, rezising it doesn't require any additional libraries. Just do:

Image newImage = yourImage.getScaledInstance(newWidth, newHeight, Image.SCALE_DEFAULT);

Ovbiously, replace newWidth and newHeight with the dimensions of the specified image.
Notice the last parameter: it tells to the runtime the algorithm you want to use for resizing.

There are algorithms that produce a very precise result, however these take a large time to complete.
You can use any of the following algorithms:

See the Javadoc for more info.

Upper memory limit?

No, there's no Python-specific limit on the memory usage of a Python application. I regularly work with Python applications that may use several gigabytes of memory. Most likely, your script actually uses more memory than available on the machine you're running on.

In that case, the solution is to rewrite the script to be more memory efficient, or to add more physical memory if the script is already optimized to minimize memory usage.


Your script reads the entire contents of your files into memory at once (line = u.readlines()). Since you're processing files up to 20 GB in size, you're going to get memory errors with that approach unless you have huge amounts of memory in your machine.

A better approach would be to read the files one line at a time:

for u in files:
     for line in u: # This will iterate over each line in the file
         # Read values from the line, do necessary calculations

How to open .dll files to see what is written inside?

I use the Jetbrains Dot peek Software , you can try that too

integrating barcode scanner into php application?

If you have Bluetooth, Use twedge on windows and getblue app on android, they also have a few videos of it. It's made by TEC-IT. I've got it to work by setting the interface option to bluetooth server in TWedge and setting the output setting in getblue to Bluetooth client and selecting my computer from the Bluetooth devices list. Make sure your computer and phone is paired. Also to get the barcode as input set the action setting in TWedge to Keyboard Wedge. This will allow for you to first click the input text box on said form, then scan said product with your phone and wait a sec for the barcode number to be put into the text box. Using this method requires no php that doesn't already exist in your current form processing, just process the text box as usual and viola your phone scans bar codes, sends them to your pc via Bluetooth wirelessly, your computer inserts the barcode into whatever text field is selected in any application or website. Hope this helps.

Django DateField default options

I think a better way to solve this would be to use the datetime callable:

from datetime import datetime

date = models.DateField(

Note that no parenthesis were used. If you used parenthesis you would invoke the now() function just once (when the model is created). Instead, you pass the callable as an argument, thus being invoked everytime an instance of the model is created.

Credit to Django Musings. I've used it and works fine.

Can we update primary key values of a table?

It is commonly agreed that primary keys should be immutable (or as stable as possible since immutability can not be enforced in the DB). While there is nothing that will prevent you from updating a primary key (except integrity constraint), it may not be a good idea:

From a performance point of view:

  • You will need to update all foreign keys that reference the updated key. A single update can lead to the update of potentially lots of tables/rows.
  • If the foreign keys are unindexed (!!) you will have to maintain a lock on the children table to ensure integrity. Oracle will only hold the lock for a short time but still, this is scary.
  • If your foreign keys are indexed (as they should be), the update will lead to the update of the index (delete+insert in the index structure), this is generally more expensive than the actual update of the base table.
  • In ORGANIZATION INDEX tables (in other RDBMS, see clustered primary key), the rows are physically sorted by the primary key. A logical update will result in a physical delete+insert (more expensive)

Other considerations:

  • If this key is referenced in any external system (application cache, another DB, export...), the reference will be broken upon update.
  • additionaly, some RDBMS don't support CASCADE UPDATE, in particular Oracle.

In conclusion, during design, it is generally safer to use a surrogate key in lieu of a natural primary key that is supposed not to change -- but may eventually need to be updated because of changed requirements or even data entry error.

If you absolutely have to update a primary key with children table, see this post by Tom Kyte for a solution.

JVM property -Dfile.encoding=UTF8 or UTF-8?

It will be:


See here for the definitions.

How do I format a date in VBA with an abbreviated month?

I'm using

Sheet1.Range("E2", "E3000").NumberFormat = "dd/mm/yyyy hh:mm:ss"

to format a column

So I guess

Sheet1.Range("E2", "E3000").NumberFormat = "MMM dd yyyy"

would do the trick for you.

More: NumberFormat function.

How do I pass multiple attributes into an Angular.js attribute directive?

This worked for me and I think is more HTML5 compliant. You should change your html to use 'data-' prefix

<div data-example-directive data-number="99"></div>

And within the directive read the variable's value:

scope: {
        number : "=",

How to manually force a commit in a @Transactional method?

I had a similar use case during testing hibernate event listeners which are only called on commit.

The solution was to wrap the code to be persistent into another method annotated with REQUIRES_NEW. (In another class) This way a new transaction is spawned and a flush/commit is issued once the method returns.


Keep in mind that this might influence all the other tests! So write them accordingly or you need to ensure that you can clean up after the test ran. - <customErrors mode="Off"/> error when trying to access working webpage

For example in my case I accidentaly changed role of some users to incorrect, and my application got error during starting (NullReferenceException). When I fixed it - the app starts fine.

In Java, what purpose do the keywords `final`, `finally` and `finalize` fulfil?


final can be used to mark a variable "unchangeable"

private final String name = "foo";  //the reference name can never change

final can also make a method not "overrideable"

public final String toString() {  return "NULL"; }

final can also make a class not "inheritable". i.e. the class can not be subclassed.

public final class finalClass {...}
public class classNotAllowed extends finalClass {...} // Not allowed


finally is used in a try/catch statement to execute code "always"

try {
  //do stuff
} catch (SomeException se) {
  //handle se
} finally {
  lock.unlock(); //always executed, even if Exception or Error or se

Java 7 has a new try with resources statement that you can use to automatically close resources that explicitly or implicitly implement or java.lang.AutoCloseable


finalize is called when an object is garbage collected. You rarely need to override it. An example:

protected void finalize() {
  //free resources (e.g. unallocate memory)

Cannot resolve method 'getSupportFragmentManager ( )' inside Fragment

For me I made sure to import v4 like this:


Then used:


Need to navigate to a folder in command prompt

In MS-DOS COMMAND.COM shell, you have to use:


cd \windows\movie

If by chance you actually meant "Windows command prompt" (which is not MS-DOS and not DOS at all), then you can use cd /d d:\windows\movie.

AngularJS directive does not update on scope variable changes

We can try this

$scope.$apply(function() {
    $scope.step1 = true;
    //scope.list2.length = 0;

MVC Return Partial View as JSON

Instead of RenderViewToString I prefer a approach like

return Json(new { Url = Url.Action("Evil", model) });

then you can catch the result in your javascript and do something like

success: function(data) {
    $.post(data.Url, function(partial) { 

hardcoded string "row three", should use @string resource

It is not good practice to hard code strings into your layout files/ code. You should add them to a string resource file and then reference them from your layout.

  1. This allows you to update every occurrence of the same word in all
    layouts at the same time by just editing your strings.xml file.
  2. It is also extremely useful for supporting multiple languages as a separate strings.xml file can be used for each supported language
  3. the actual point of having the @string system please read over the localization documentation. It allows you to easily locate text in your app and later have it translated.
  4. Strings can be internationalized easily, allowing your application to support multiple languages with a single application package file (APK).


  • Lets say you used same string in 10 different locations in the code. What if you decide to alter it? Instead of searching for where all it has been used in the project you just change it once and changes are reflected everywhere in the project.
  • Strings don’t clutter up your application code, leaving it clear and easy to maintain.

PostgreSQL - query from bash script as database user 'postgres'

Try this one:

psql -U postgres -d database_name -c "SELECT c_defaults  FROM user_info WHERE c_uid = 'testuser'"

Or using su:

su -c "psql -d database_name -c \"SELECT c_defaults  FROM user_info WHERE c_uid = 'testuser'\"" postgres

And also sudo:

sudo -u postgres -H -- psql -d database_name -c "SELECT c_defaults  FROM user_info WHERE c_uid = 'testuser'"

Dynamically generating a QR code with PHP

I have been using google qrcode api for sometime, but I didn't quite like this because it requires me to be on the Internet to access the generated image.

I did a little comand-line research and found out that linux has a command line tool qrencode for generating qr-codes.

I wrote this little script. And the good part is that the generated image is less than 1KB in size. Well the supplied data is simply a url.

$url = ($_SERVER['HTTPS'] ? "https://" : "http://").$_SERVER['HTTP_HOST'].'/profile.php?id='.$_GET['pid'];
$img = shell_exec('qrencode --output=- -m=1 '.escapeshellarg($url));

$imgData = "data:image/png;base64,".base64_encode($img);

Then in the html I load the image:

<img class="emrQRCode" src="<?=$imgData ?>" />

You just need to have installed it. [most imaging apps on linux would have installed it under the hood without you realizing.

Pythonic way to return list of every nth item in a larger list

You can use the slice operator like this:

l = [1,2,3,4,5]
l2 = l[::2] # get subsequent 2nd item

Where can I get Google developer key

First activate Google+ API, then you will get "Simple API access" box, from there you can get developer key as API key or read this:

What exactly does numpy.exp() do?

It calculates ex for each x in your list where e is Euler's number (approximately 2.718). In other words, np.exp(range(5)) is similar to [math.e**x for x in range(5)].

How do you display code snippets in MS Word preserving format and syntax highlighting?

You can also use SciTE to paste code if you don't want to install heavy IDEs and then download plugins for all the code you're making. Simply choose your language from the language menu, type your code, high-light code, select Edit->Copy as RTF, paste into Word with formatting (default paste).

SciTE supports the following languages but probably has support for others: Abaqus*, Ada, ANS.1 MIB definition files*, APDL, Assembler (NASM, MASM), Asymptote*, AutoIt*, Avenue*, Batch files (MS-DOS), Baan*, Bash*, BlitzBasic*, Bullant*, C/C++/C#, Clarion, cmake*, conf (Apache), CSound, CSS*, D, diff files*, E-Script*, Eiffel*, Erlang*, Flagship (Clipper / XBase), Flash (ActionScript), Fortran*, Forth*, GAP*, Gettext, Haskell, HTML*, HTML with embedded JavaScript, VBScript, PHP and ASP*, Gui4Cli*, IDL - both MSIDL and XPIDL*, INI, properties* and similar, InnoSetup*, Java*, JavaScript*, LISP*, LOT*, Lout*, Lua*, Make, Matlab*, Metapost*, MMIXAL, MSSQL, nnCron, NSIS*, Objective Caml*, Opal, Octave*, Pascal/Delphi*, Perl, most of it except for some ambiguous cases*, PL/M*, Progress*, PostScript*, POV-Ray*, PowerBasic*, PowerShell*, PureBasic*, Python*, R*, Rebol*, Ruby*, Scheme*, scriptol*, Specman E*, Spice, Smalltalk, SQL and PLSQL, TADS3*, TeX and LaTeX, Tcl/Tk*, VB and VBScript*, Verilog*, VHDL*, XML*, YAML*.

How to use function srand() with time.h?

You need to call srand() once, to randomize the seed, and then call rand() in your loop:

#include <stdlib.h>
#include <time.h>

#define size 10

srand(time(NULL)); // randomize seed

    Arr[i] = rand()%size;

Summarizing multiple columns with dplyr?

You can simply pass more arguments to summarise:

df %>% group_by(grp) %>% summarise(mean(a), mean(b), mean(c), mean(d))

Source: local data frame [3 x 5]

  grp  mean(a)  mean(b)  mean(c) mean(d)
1   1 2.500000 3.500000 2.000000     3.0
2   2 3.800000 3.200000 3.200000     2.8
3   3 3.666667 3.333333 2.333333     3.0

The matching wildcard is strict, but no declaration can be found for element 'context:component-scan

Add This Two Schema locations. That's enough and Efficient instead of adding all the unnecessary schema

Angular2 If ngModel is used within a form tag, either the name attribute must be set or the form

<select name="country" formControlName="country" id="country" 
       class="formcontrol form-control-element" [(ngModel)]="country">
   <option value="90">Turkey</option>
   <option value="1">USA</option>
   <option value="30">Greece</option>

Those are the three things need to use ngModel inside a formGroup directive.

Note that same name should be used.

Executing a command stored in a variable from PowerShell

Try invoking your command with Invoke-Expression:

Invoke-Expression $cmd1

Here is a working example on my machine:

$cmd = "& 'C:\Program Files\7-zip\7z.exe' a -tzip c:\temp\ c:\temp\test.txt"
Invoke-Expression $cmd

iex is an alias for Invoke-Expression so you could do:

iex $cmd1

For a full list : Visit for more Powershell stuff.

Good Luck...

Convert textbox text to integer

If your SQL database allows Null values for that field try using int? value like that :

if (this.txtboxname.Text == "" || this.txtboxname.text == null)
     value = null;
     value = Convert.ToInt32(this.txtboxname.Text);

Take care that Convert.ToInt32 of a null value returns 0 !

Convert.ToInt32(null) returns 0

Javascript Drag and drop for touch devices

I had the same solution as gregpress answer, but my draggable items used a class instead of an id. It seems to work.

var $target = $(;  
if( $target.hasClass('draggable') ) {  

Android Left to Right slide animation

Made a sample code implementing the same with slide effects from left, right, top and bottom. (For those who dont want to make all those anim xml files :) )

Checkout out the code on github

NoClassDefFoundError - Eclipse and Android

i spent two days trying to solve this issue after updating ADT. finally i was lucky to get this post here:

which led me in the right direction. when you follow the solution - remember to replace the android support library of all your projects to the same version (remove it and re-install it to the projects). i hope this helps - good luck

iTerm 2: How to set keyboard shortcuts to jump to beginning/end of line?

The old fashion emacs bindings can still work in iterm2 and os x terminal:

Preferences -> Profiles -> Keys (sub tab in profiles)

  • Set Left/Right option <kbd>?</kbd> key acts as +Esc (similar in os x terminal)

This should enable alt-f and alt-b for moving words by words. (Still ctrl-a and ctrl-e always work as usual)

If set as meta those old bindings will work while some iterm2 bindings unavailable.

How do I enable logging for Spring Security?

You can easily enable debugging support using an option for the @EnableWebSecurity annotation:

@EnableWebSecurity(debug = true)
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {

How to get domain URL and application name?

Take a look at the documentation for HttpServletRequest.
In order to build the URL in your example you will need to use:

  • getScheme()
  • getServerName()
  • getServerPort()
  • getContextPath()

Here is a method that will return your example:

public static String getURLWithContextPath(HttpServletRequest request) {
   return request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + request.getContextPath();

How to execute only one test spec with angular-cli

I solved this problem for myself using grunt. I have the grunt script below. What the script does is takes the command line parameter of the specific test to run and creates a copy of test.ts and puts this specific test name in there.

To run this, first install grunt-cli using:

npm install -g grunt-cli

Put the below grunt dependencies in your package.json:

"grunt": "^1.0.1",
"grunt-contrib-clean": "^1.0.0",
"grunt-contrib-copy": "^1.0.0",
"grunt-exec": "^2.0.0",
"grunt-string-replace": "^1.3.1"

To run it save the below grunt file as Gruntfile.js in your root folder. Then from command line run it as:

grunt --target=app.component

This will run app.component.spec.ts.

Grunt file is as below:

This gruntfile is used to run a specific test in watch mode. Example: To run app.component.spec.ts , the Command is: 
grunt --target=app.component
Do not specific .spec.ts. If no target is specified it will run all tests.
module.exports = function(grunt) {
var target = grunt.option('target') || '';
  // Project configuration.
    pkg: grunt.file.readJSON('package.json'),
    clean: ['temp.conf.js','src/temp-test.ts'],
    copy: {
      main: {
        files: [
             {expand: false, cwd: '.', src: ['karma.conf.js'], dest: 'temp.conf.js'},
             {expand: false, cwd: '.', src: ['src/test.ts'], dest: 'src/temp-test.ts'}
    'string-replace': {
          dist: {
            files: {
              'temp.conf.js': 'temp.conf.js',
              'src/temp-test.ts': 'src/temp-test.ts'
            options: {
              replacements: [{
                pattern: /test.ts/ig,
                replacement: 'temp-test.ts'
                pattern: /const context =.*/ig,
                replacement: 'const context = require.context(\'./\', true, /'+target+'\\\.spec\\\.ts$/);'
    'exec': {
        sleep: {
          //The sleep command is needed here, else webpack compile fails since it seems like the files in the previous step were touched too recently
          command: 'ping -n 4 > nul',
          stdout: true,
          stderr: true
        ng_test: {
          command: 'ng test --config=temp.conf.js',
          stdout: true,
          stderr: true

  // Load the plugin that provides the "uglify" task.
  // Default task(s).
  grunt.registerTask('default', ['clean','copy','string-replace','exec']);


Python: How exactly can you take a string, split it, reverse it and join it back together again?

Do you mean like this?

import string

deleter=string.maketrans('()[]','    ')
# a b c  d
# ['a', 'b', 'c', 'd']
# ['d', 'c', 'b', 'a']
print(' '.join(reversed(astr.translate(deleter).split())))
# d c b a

Putting HTML inside Html.ActionLink(), plus No Link Text?

I thought this might be useful when using bootstrap and some glypicons:

<a class="btn btn-primary" 
    href="<%: Url.Action("Download File", "Download", 
    new { id = msg.Id, distributorId = msg.DistributorId }) %>">
    <span class="glyphicon glyphicon-paperclip"></span>

This will show an A tag, with a link to a controller, with a nice paperclip icon on it to represent a download link, and the html output is kept clean

android: how to align image in the horizontal center of an imageview?

Try this code :


                android:src="@drawable/back_detail" />

ldap query for group members

The good way to get all the members from a group is to, make the DN of the group as the searchDN and pass the "member" as attribute to get in the search function. All of the members of the group can now be found by going through the attribute values returned by the search. The filter can be made generic like (objectclass=*).

How to convert a char array to a string?

Another solution might look like this,

char arr[] = "mom";
std::cout << "hi " << std::string(arr);

which avoids using an extra variable.

What is the difference between spark.sql.shuffle.partitions and spark.default.parallelism?

spark.default.parallelism is the default number of partition set by spark which is by default 200. and if you want to increase the number of partition than you can apply the property spark.sql.shuffle.partitions to set number of partition in the spark configuration or while running spark SQL.

Normally this spark.sql.shuffle.partitions it is being used when we have a memory congestion and we see below error: spark error:java.lang.IllegalArgumentException: Size exceeds Integer.MAX_VALUE

so set your can allocate a partition as 256 MB per partition and that you can use to set for your processes.

also If number of partitions is near to 2000 then increase it to more than 2000. As spark applies different logic for partition < 2000 and > 2000 which will increase your code performance by decreasing the memory footprint as data default is highly compressed if >2000.

MySQL with Node.js

Since this is an old thread just adding an update:

To install the MySQL node.js driver:

If you run just npm install mysql, you need to be in the same directory that your run your server. I would advise to do it as in one of the following examples:

For global installation:

npm install -g mysql

For local installation:

1- Add it to your package.json in the dependencies:

"dependencies": {
    "mysql": "~2.3.2",

2- run npm install

Note that for connections to happen you will also need to be running the mysql server (which is node independent)

To install MySQL server:

There are a bunch of tutorials out there that explain this, and it is a bit dependent on operative system. Just go to google and search for how to install mysql server [Ubuntu|MacOSX|Windows]. But in a sentence: you have to go to and install it.

With ng-bind-html-unsafe removed, how do I inject HTML?

You indicated that you're using Angular 1.2.0... as one of the other comments indicated, ng-bind-html-unsafe has been deprecated.

Instead, you'll want to do something like this:

<div ng-bind-html="preview_data.preview.embed.htmlSafe"></div>

In your controller, inject the $sce service, and mark the HTML as "trusted":

myApp.controller('myCtrl', ['$scope', '$sce', function($scope, $sce) {
  // ...
  $scope.preview_data.preview.embed.htmlSafe = 

Note that you'll want to be using 1.2.0-rc3 or newer. (They fixed a bug in rc3 that prevented "watchers" from working properly on trusted HTML.)

jquery drop down menu closing by clicking outside

how to have a click event outside of the dropdown menu so that it close the dropdown menu ? Heres the code

$(document).click(function (e) {
    var container = $(".dropDown");

    //check if the clicked area is dropDown or not
    if (container.has( === 0) {

Bash command line and input limit

There is a buffer limit of something like 1024. The read will simply hang mid paste or input. To solve this use the -e option.

-e use Readline to obtain the line in an interactive shell

Change your read to read -e and annoying line input hang goes away.

Download TS files from video stream

using this post

  • Open Firefox / chrome

  • open page the video

  • Play Video

  • click F12 on keyboard -> network

  • in Filter URLs ts

  • copy link of ts

  • remove index and ts extension from link

    for example:

    will be copied as

insert in below script under LINK


# insert here urls

'' # replace this with your url 


mkdir my-videos
cd mkdir my-videos


for URL in ${LINK[@]}
  # create folder for streaming media
  CNT=$((CNT + 1))
  mkdir $CNT
  cd $CNT



   # download all videos
   wget $URL'_'{0..1200}.ts

   # link videos
   echo $DIR'_'{0..1200}.ts | tr " " "\n" > tslist
   while read line; do cat $line >> $CNT.mp4; done < tslist

   rm -rf media* tslist
   ) &
   cd ..




adding script in python - runs on windows and linux

import urllib.request
import os
import shutil

my_lessons = [
    "" # replace this with your url 


lesson_dir = "my_vids"
    print "ok"


for lesson, dwn_link in enumerate(my_lessons):
    print ("downloading lesson  %d.. " % (lesson), dwn_link)
    file_name = '%04d.mp4' % lesson
    f = open(file_name, 'ab')
    for x in range(0, 1200):
            rsp = urllib.request.urlopen(dwn_link + "_%04d.ts" % (x) )
        file_name = '%d.mp4' % lesson
        print "downloading  %d.ts" % (x)

print "done good luck!! ==================  "

if the script fails, or downloads empty file, try removing the try wrap to see what fails

Apply CSS Style to child elements

.test * {padding: 40px 100px 40px 50px;}

Is there a 'box-shadow-color' property?

Maybe this is new (I am also pretty crap at css3), but I have a page that uses exactly what you suggest:

-moz-box-shadow: 10px 10px 5px #384e69;
-webkit-box-shadow: 10px 10px 5px #384e69;
box-shadow: 10px 10px 5px #384e69;}

.. and it works fine for me (in Chrome at least).

How to deselect all selected rows in a DataGridView control?

i found out why my first row was default selected and found out how to not select it by default.

By default my datagridview was the object with the first tab-stop on my windows form. Making the tab stop first on another object (maybe disabling tabstop for the datagrid at all will work to) disabled selecting the first row

How to format a duration in java? (e.g format H:MM:SS)

How about the following function, which returns either +H:MM:SS or +H:MM:SS.sss

public static String formatInterval(final long interval, boolean millisecs )
    final long hr = TimeUnit.MILLISECONDS.toHours(interval);
    final long min = TimeUnit.MILLISECONDS.toMinutes(interval) %60;
    final long sec = TimeUnit.MILLISECONDS.toSeconds(interval) %60;
    final long ms = TimeUnit.MILLISECONDS.toMillis(interval) %1000;
    if( millisecs ) {
        return String.format("%02d:%02d:%02d.%03d", hr, min, sec, ms);
    } else {
        return String.format("%02d:%02d:%02d", hr, min, sec );

What does "\r" do in the following script?

\r is the ASCII Carriage Return (CR) character.

There are different newline conventions used by different operating systems. The most common ones are:

  • CR+LF (\r\n);
  • LF (\n);
  • CR (\r).

The \n\r (LF+CR) looks unconventional.

edit: My reading of the Telnet RFC suggests that:

  1. CR+LF is the standard newline sequence used by the telnet protocol.
  2. LF+CR is an acceptable substitute:

The sequence "CR LF", as defined, will cause the NVT to be positioned at the left margin of the next print line (as would, for example, the sequence "LF CR").

AngularJS - Create a directive that uses ng-model

I took a combo of all answers, and now have two ways of doing this with the ng-model attribute:

  • With a new scope which copies ngModel
  • With the same scope which does a compile on link

var app = angular.module('model', []);_x000D_
app.controller('MainCtrl', function($scope) {_x000D_
  $ = "Felipe";_x000D_
  $scope.label = "The Label";_x000D_
app.directive('myDirectiveWithScope', function() {_x000D_
  return {_x000D_
    restrict: 'E',_x000D_
    scope: {_x000D_
      ngModel: '=',_x000D_
    // Notice how label isn't copied_x000D_
    template: '<div class="some"><label>{{label}}: <input ng-model="ngModel"></label></div>',_x000D_
    replace: true_x000D_
app.directive('myDirectiveWithChildScope', function($compile) {_x000D_
  return {_x000D_
    restrict: 'E',_x000D_
    scope: true,_x000D_
    // Notice how label is visible in the scope_x000D_
    template: '<div class="some"><label>{{label}}: <input></label></div>',_x000D_
    replace: true,_x000D_
    link: function ($scope, element) {_x000D_
      // element will be the div which gets the ng-model on the original directive_x000D_
      var model = element.attr('ng-model');_x000D_
      $('input',element).attr('ng-model', model);_x000D_
      return $compile(element)($scope);_x000D_
app.directive('myDirectiveWithoutScope', function($compile) {_x000D_
  return {_x000D_
    restrict: 'E',_x000D_
    template: '<div class="some"><label>{{$parent.label}}: <input></label></div>',_x000D_
    replace: true,_x000D_
    link: function ($scope, element) {_x000D_
      // element will be the div which gets the ng-model on the original directive_x000D_
      var model = element.attr('ng-model');_x000D_
      return $compile($('input',element).attr('ng-model', model))($scope);_x000D_
app.directive('myReplacedDirectiveIsolate', function($compile) {_x000D_
  return {_x000D_
    restrict: 'E',_x000D_
    scope: {},_x000D_
    template: '<input class="some">',_x000D_
    replace: true_x000D_
app.directive('myReplacedDirectiveChild', function($compile) {_x000D_
  return {_x000D_
    restrict: 'E',_x000D_
    scope: true,_x000D_
    template: '<input class="some">',_x000D_
    replace: true_x000D_
app.directive('myReplacedDirective', function($compile) {_x000D_
  return {_x000D_
    restrict: 'E',_x000D_
    template: '<input class="some">',_x000D_
    replace: true_x000D_
.some {_x000D_
  border: 1px solid #cacaca;_x000D_
  padding: 10px;_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<div ng-app="model" ng-controller="MainCtrl">_x000D_
  This scope value <input ng-model="name">, label: "{{label}}"_x000D_
    <li>With new isolate scope (label from parent):_x000D_
      <my-directive-with-scope ng-model="name"></my-directive-with-scope>_x000D_
    <li>With new child scope:_x000D_
      <my-directive-with-child-scope ng-model="name"></my-directive-with-child-scope>_x000D_
    <li>Same scope:_x000D_
      <my-directive-without-scope ng-model="name"></my-directive-without-scope>_x000D_
    <li>Replaced element, isolate scope:_x000D_
      <my-replaced-directive-isolate ng-model="name"></my-replaced-directive-isolate>_x000D_
    <li>Replaced element, child scope:_x000D_
      <my-replaced-directive-child ng-model="name"></my-replaced-directive-child>_x000D_
    <li>Replaced element, same scope:_x000D_
      <my-replaced-directive ng-model="name"></my-replaced-directive>_x000D_
  <p>Try typing in the child scope ones, they copy the value into the child scope which breaks the link with the parent scope._x000D_
  <p>Also notice how removing jQuery makes it so only the new-isolate-scope version works._x000D_
  <p>Finally, note that the replace+isolate scope only works in AngularJS >=1.2.0_x000D_

I'm not sure I like the compiling at link time. However, if you're just replacing the element with another you don't need to do that.

All in all I prefer the first one. Simply set scope to {ngModel:"="} and set ng-model="ngModel" where you want it in your template.

Update: I inlined the code snippet and updated it for Angular v1.2. Turns out that isolate scope is still best, especially when not using jQuery. So it boils down to:

  • Are you replacing a single element: Just replace it, leave the scope alone, but note that replace is deprecated for v2.0:

    app.directive('myReplacedDirective', function($compile) {
      return {
        restrict: 'E',
        template: '<input class="some">',
        replace: true
  • Otherwise use this:

    app.directive('myDirectiveWithScope', function() {
      return {
        restrict: 'E',
        scope: {
          ngModel: '=',
        template: '<div class="some"><input ng-model="ngModel"></div>'

Make UINavigationBar transparent

In iOS5 you can do this to make the navigation bar transparent:

nav.navigationBar.translucent = YES; // Setting this slides the view up, underneath the nav bar (otherwise it'll appear black)
const float colorMask[6] = {222, 255, 222, 255, 222, 255};
UIImage *img = [[UIImage alloc] init];
UIImage *maskedImage = [UIImage imageWithCGImage: CGImageCreateWithMaskingColors(img.CGImage, colorMask)];

[nav.navigationBar setBackgroundImage:maskedImage forBarMetrics:UIBarMetricsDefault]; 
[img release];

How to check if a variable is empty in python?

See also this previous answer which recommends the not keyword

How to check if a list is empty in Python?

It generalizes to more than just lists:

>>> a = ""
>>> not a

>>> a = []
>>> not a

>>> a = 0
>>> not a

>>> a = 0.0
>>> not a

>>> a = numpy.array([])
>>> not a

Notably, it will not work for "0" as a string because the string does in fact contain something - a character containing "0". For that you have to convert it to an int:

>>> a = "0"
>>> not a

>>> a = '0'
>>> not int(a)

Convert HTML + CSS to PDF

I've tried a lot of different libraries for PHP. All the listed I've tried. In my opinion TCPDF library is the best compromise performance/usability. It's very simply to install and use, also good performance in small medium application. If you need high performance and very big PDF document, use Zend_PDF module, but get ready to coding hard!

Start redis-server with config file

To start redis with a config file all you need to do is specifiy the config file as an argument:

redis-server /root/config/redis.rb

Instead of using and killing PID's I would suggest creating an init script for your service

I would suggest taking a look at the Installing Redis more properly section of It will walk you through setting up an init script with redis so you can just do something like service redis_server start and service redis_server stop to control your server.

I am not sure exactly what distro you are using, that article describes instructions for a Debian based distro. If you are are using a RHEL/Fedora distro let me know, I can provide you with instructions for the last couple of steps, the config file and most of the other steps will be the same.

WP -- Get posts by category?

Check here :

Note: The category parameter needs to be the ID of the category, and not the category name.

Python executable not finding libpython shared library

Try the following:

LD_LIBRARY_PATH=/usr/local/lib /usr/local/bin/python

Replace /usr/local/lib with the folder where you have installed if it is not in /usr/local/lib.

If this works and you want to make the changes permanent, you have two options:

  1. Add export LD_LIBRARY_PATH=/usr/local/lib to your .profile in your home directory (this works only if you are using a shell which loads this file when a new shell instance is started). This setting will affect your user only.

  2. Add /usr/local/lib to /etc/ and run ldconfig. This is a system-wide setting of course.

Visual Studio Code: Auto-refresh file changes

SUPER-SHIFT-p > File: Revert File is the only way

(where SUPER is Command on Mac and Ctrl on PC)

c# write text on bitmap

If you want wrap your text, then you should draw your text in a rectangle:

RectangleF rectF1 = new RectangleF(30, 10, 100, 122);
e.Graphics.DrawString(text1, font1, Brushes.Blue, rectF1);


Python reshape list to ndim array

You can specify the interpretation order of the axes using the order parameter:

np.reshape(arr, (2, -1), order='F')

Why does NULL = NULL evaluate to false in SQL server

null is unknown in sql so we cant expect two unknowns to be same.

However you can get that behavior by setting ANSI_NULLS to Off(its On by Default) You will be able to use = operator for nulls

if null=null
print 1
print 2
set ansi_nulls on
if null=null
print 1
print 2

grep for special characters in Unix

You could try removing any alphanumeric characters and space. And then use -n will give you the line number. Try following:

grep -vn "^[a-zA-Z0-9 ]*$" application.log

Graphviz: How to go from .dot to a graph?

there is no requirement of any conversion.

We can simply use xdot command in Linux which is an Interactive viewer for Graphviz dot files.

ex: xdot

for more infor:

Bootstrap 3: Scroll bars

You need to use the overflow option, but with the following parameters:

.nav {

Use overflow-y:auto; so the scrollbar only appears when the content exceeds the maximum height.

If you use overflow-y:scroll, the scrollbar will always be visible - on all .nav - regardless if the content exceeds the maximum heigh or not.

Presumably you want something that adapts itself to the content rather then the the opposite.

Hope it may helpful

Detect element content changes with jQuery

I'm developing tiny JS library called mutabor ( which intended to simplify usage of DOM Mutation Events. See demo.html for examples.

How to add facebook share button on my website?

For Facebook share with an image without an API and using a # to deep link into a sub page, the trick was to share the image as picture=

The variable mainUrl would be

var d1 = $('.targ .t1').text();
var d2 = $('.targ .t2').text();
var d3 = $('.targ .t3').text();
var d4 = $('.targ .t4').text();
var descript_ = d1 + ' ' + d2 + ' ' + d3 + ' ' + d4;
var descript = encodeURIComponent(descript_);

var imgUrl_ = 'path/to/mypic_'+id+'.jpg';
var imgUrl = mainUrl + encodeURIComponent(imgUrl_);

var shareLink = mainUrl + encodeURIComponent('mypage.html#' + id);

var fbShareLink = shareLink + '&picture=' + imgUrl + '&description=' + descript;
var twShareLink = 'text=' + descript + '&url=' + shareLink;

// facebook
$(".my-btn .facebook").off("tap click").on("tap click",function(){
  var fbpopup ="" + fbShareLink, "pop", "width=600, height=400, scrollbars=no");
  return false;

// twitter
$(".my-btn .twitter").off("tap click").on("tap click",function(){
  var twpopup ="" + twShareLink , "pop", "width=600, height=400, scrollbars=no");
  return false;

How to get a specific column value from a DataTable in c#

The table normally contains multiple rows. Use a loop and use row.Field<string>(0) to access the value of each row.

foreach(DataRow row in dt.Rows)
    string file = row.Field<string>("File");

You can also access it via index:

foreach(DataRow row in dt.Rows)
    string file = row.Field<string>(0);

If you expect only one row, you can also use the indexer of DataRowCollection:

string file = dt.Rows[0].Field<string>(0); 

Since this fails if the table is empty, use dt.Rows.Count to check if there is a row:

if(dt.Rows.Count > 0)
    file = dt.Rows[0].Field<string>(0);

isPrime Function for Python Language

int(n**0.5) is the floor value of sqrt(n) which you confused with power 2 of n (n**2). If n is not prime, there must be two numbers 1 < i <= j < n such that: i * j = n.

Now, since sqrt(n) * sqrt(n) = n assuming one of i,j is bigger than (or equals to) sqrt(n) - it means that the other one has to be smaller than (or equals to) sqrt(n).

Since that is the case, it's good enough to iterate the integer numbers in the range [2, sqrt(n)]. And that's exactly what the code that was posted is doing.

If you want to come out as a real smartass, use the following one-liner function:

import re
def is_prime(n):    
    return not re.match(r'^1?$|^(11+?)\1+$',n*'1')

An explanation for the "magic regex" can be found here

How do I animate constraint changes?

I appreciate the answer provided, but I think it would be nice to take it a bit further.

The basic block animation from the documentation

[containerView layoutIfNeeded]; // Ensures that all pending layout operations have been completed
[UIView animateWithDuration:1.0 animations:^{
     // Make all constraint changes here
     [containerView layoutIfNeeded]; // Forces the layout of the subtree animation block and then captures all of the frame changes

but really this is a very simplistic scenario. What if I want to animate subview constraints via the updateConstraints method?

An animation block that calls the subviews updateConstraints method

[self.view layoutIfNeeded];
[self.subView setNeedsUpdateConstraints];
[self.subView updateConstraintsIfNeeded];
[UIView animateWithDuration:1.0f delay:0.0f options:UIViewAnimationOptionLayoutSubviews animations:^{
    [self.view layoutIfNeeded];
} completion:nil];

The updateConstraints method is overridden in the UIView subclass and must call super at the end of the method.

- (void)updateConstraints
    // Update some constraints

    [super updateConstraints];

The AutoLayout Guide leaves much to be desired but it is worth reading. I myself am using this as part of a UISwitch that toggles a subview with a pair of UITextFields with a simple and subtle collapse animation (0.2 seconds long). The constraints for the subview are being handled in the UIView subclasses updateConstraints methods as described above.

Write to file, but overwrite it if it exists

The >> redirection operator will append lines to the end of the specified file, where-as the single greater than > will empty and overwrite the file.

echo "text" > 'Users/Name/Desktop/TheAccount.txt'

git cherry-pick says "...38c74d is a merge but no -m option was given"

@Borealid's answer is correct, but suppose that you don't care about preserving the exact merging history of a branch and just want to cherry-pick a linearized version of it. Here's an easy and safe way to do that:

Starting state: you are on branch X, and you want to cherry-pick the commits Y..Z.

  1. git checkout -b tempZ Z
  2. git rebase Y
  3. git checkout -b newX X
  4. git cherry-pick Y..tempZ
  5. (optional) git branch -D tempZ

What this does is to create a branch tempZ based on Z, but with the history from Y onward linearized, and then cherry-pick that onto a copy of X called newX. (It's safer to do this on a new branch rather than to mutate X.) Of course there might be conflicts in step 4, which you'll have to resolve in the usual way (cherry-pick works very much like rebase in that respect). Finally it deletes the temporary tempZ branch.

If step 2 gives the message "Current branch tempZ is up to date", then Y..Z was already linear, so just ignore that message and proceed with steps 3 onward.

Then review newX and see whether that did what you wanted.

(Note: this is not the same as a simple git rebase X when on branch Z, because it doesn't depend in any way on the relationship between X and Y; there may be commits between the common ancestor and Y that you didn't want.)

Running Python from Atom

To run the python file on mac.

  1. Open the preferences in atom ide. To open the preferences press 'command + . ' ( ? + , )
  2. Click on the install in the preferences to install packages.

  3. Search for package "script" and click on install

  4. Now open the python file(with .py extension ) you want to run and press 'control + r ' (^ + r)

Google MAP API Uncaught TypeError: Cannot read property 'offsetWidth' of null

Also, make sure you're not placing hash symbol (#) inside your selector in a

    document.getElementById('#map') // bad

    document.getElementById('map') // good

statement. It's not a jQuery. Just a quick reminder for someone in a hurry.

Android, How to read QR code in my application?

Use a QR library like ZXing... I had very good experience with it, QrDroid is much buggier. If you must rely on an external reader, rely on a standard one like Google Goggles!

How to Copy Contents of One Canvas to Another Canvas Locally

@robert-hurst has a cleaner approach.

However, this solution may also be used, in places when you actually want to have a copy of Data Url after copying. For example, when you are building a website that uses lots of image/canvas operations.

    // select canvas elements
    var sourceCanvas = document.getElementById("some-unique-id");
    var destCanvas = document.getElementsByClassName("some-class-selector")[0];

    //copy canvas by DataUrl
    var sourceImageData = sourceCanvas.toDataURL("image/png");
    var destCanvasContext = destCanvas.getContext('2d');

    var destinationImage = new Image;
    destinationImage.onload = function(){
    destinationImage.src = sourceImageData;

/etc/apt/sources.list" E212: Can't open file for writing

You just need to access to Gemfile with root access. Before vi:


sudo su -


vi ~/...

How do I prevent Eclipse from hanging on startup?

Well, I had similar behaviour while starting eclipse over X11. I forgot to tick the enable X11 forwarding in my putty.

Difference between multitasking, multithreading and multiprocessing?

Multi-programming :-

More than one task(job) process can reside into main memory at a time. It is basically design to reduce CPU wastage during I/O operation , example : if a job is executing currently and need I/O operation . I/O operation is done using DMA and processor assign to some Other job from the job queue till I/O operation of job1 completed . then job1 continue again . In this way it reduce CPU wastage .

Google Maps API - how to get latitude and longitude from Autocomplete without showing the map?

You can't get latitude/longitude from autocomplete API since the data generated by google from that API doesn't contain latitude and logitude field. Example:-

   "predictions" : [
         "description" : "IIT Mumbai, Mumbai, Maharashtra, India",
         "id" : "ac3235cda973818a89b5fe21ad0f5261ac9b6723",
         "matched_substrings" : [
               "length" : 10,
               "offset" : 0
         "reference" : "CkQ0AAAAHWg-RSngiYHHdz_yqyFKmfSoBwT-_PW0k8qQDhsbiVrk7BlPHCyJb58OthledMUTGYS5Vhec1Zj2L7w9Rq0zDxIQrbn05RX1QgWHkSXsmTk1TRoU45APW2BBRIUsA3t6XBy_8s0BPPA",
         "terms" : [
               "offset" : 0,
               "value" : "IIT Mumbai"
               "offset" : 12,
               "value" : "Mumbai"
               "offset" : 20,
               "value" : "Maharashtra"
               "offset" : 33,
               "value" : "India"
         "types" : [ "establishment", "geocode" ]
   "status" : "OK"

You can use the Google API to get the Longitude and Latitude from your address. As you already said, you should implement a hidden field where the result should be inserted. Then you can save the location together with the coordinates.


I recently implemented this function in one of my projects:

function getLatLngFromAddress(city, country){

  var address = city +", "+ country;
  var geocoder = new google.maps.Geocoder();

  geocoder.geocode( { 'address': address}, function(results, status) {

    if (status == google.maps.GeocoderStatus.OK) {

    } else {
      console.log("Geocode was not successful for the following reason: " + status);

The authorization mechanism you have provided is not supported. Please use AWS4-HMAC-SHA256

In my case, the request type was wrong. I was using GET(dumb) It must be PUT.

Appending pandas dataframes generated in a for loop

you can try this.

for infile in glob.glob("*.xlsx"):
    data = pandas.read_excel(infile)

I hope it can help.

How to verify element present or visible in selenium 2 (Selenium WebDriver)

To check if element is visible we need to use element.isDisplayed(); But if we need to check for presence of element anywhere in Dom we can use following method

public boolean isElementPresentCheckUsingJavaScriptExecutor(WebElement element) {
        JavascriptExecutor jse=(JavascriptExecutor) driver;
        try {
            Object obj = jse.execute("return typeof(arguments[0]) != 'undefined' && arguments[0] != null;",
            if (obj.toString().contains("true")) {
                System.out.println("isElementPresentCheckUsingJavaScriptExecutor: SUCCESS");
                return true;
            } else {
                System.out.println("isElementPresentCheckUsingJavaScriptExecutor: FAIL");

        } catch (NoSuchElementException e) {
            System.out.println("isElementPresentCheckUsingJavaScriptExecutor: FAIL");
        return false;

Android: why is there no maxHeight for a View?

If anyone is considering using exact value for LayoutParams e.g.

setLayoutParams(new LayoutParams(Y, X );

Do remember to take into account the density of the device display otherwise you might get very odd behaviour on different devices. E.g:

Display display = getWindowManager().getDefaultDisplay();
DisplayMetrics d = new DisplayMetrics();
setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, (int)(50*d.density) ));

How to convert enum value to int?

If you want the value you are assigning in the constructor, you need to add a method in the enum definition to return that value.

If you want a unique number that represent the enum value, you can use ordinal().

How do I get the difference between two Dates in JavaScript?

If you don't care about the time component, you can use .getDate() and .setDate() to just set the date part.

So to set your end date to 2 weeks after your start date, do something like this:

function GetEndDate(startDate)
    var endDate = new Date(startDate.getTime());
    return endDate;

To return the difference (in days) between two dates, do this:

function GetDateDiff(startDate, endDate)
    return endDate.getDate() - startDate.getDate();

Finally, let's modify the first function so it can take the value returned by 2nd as a parameter:

function GetEndDate(startDate, days)
    var endDate = new Date(startDate.getTime());
    endDate.setDate(endDate.getDate() + days);
    return endDate;

How do I query between two dates using MySQL?

Your query should have date as

select * from table between `lowerdate` and `upperdate`


SELECT * FROM `objects` 
WHERE  (date_field BETWEEN '2010-01-30 14:15:55' AND '2010-09-29 10:15:55')

How do I remove the file suffix and path portion from a path string in Bash?

The basename does that, removes the path. It will also remove the suffix if given and if it matches the suffix of the file but you would need to know the suffix to give to the command. Otherwise you can use mv and figure out what the new name should be some other way.

Error :The remote server returned an error: (401) Unauthorized

I add credentials for HttpWebRequest.

myReq.UseDefaultCredentials = true;
myReq.PreAuthenticate = true;
myReq.Credentials = CredentialCache.DefaultCredentials;

send mail to multiple receiver with HTML mailto

"There are no safe means of assigning multiple recipients to a single mailto: link via HTML. There are safe, non-HTML, ways of assigning multiple recipients from a mailto: link."

For a quick fix to your problem, change your ; to a comma , and eliminate the spaces between email addresses

<a href='mailto:[email protected],[email protected]'>Email Us</a>

dd: How to calculate optimal blocksize?

As others have said, there is no universally correct block size; what is optimal for one situation or one piece of hardware may be terribly inefficient for another. Also, depending on the health of the disks it may be preferable to use a different block size than what is "optimal".

One thing that is pretty reliable on modern hardware is that the default block size of 512 bytes tends to be almost an order of magnitude slower than a more optimal alternative. When in doubt, I've found that 64K is a pretty solid modern default. Though 64K usually isn't THE optimal block size, in my experience it tends to be a lot more efficient than the default. 64K also has a pretty solid history of being reliably performant: You can find a message from the Eug-Lug mailing list, circa 2002, recommending a block size of 64K here:[email protected]/msg12073.html

For determining THE optimal output block size, I've written the following script that tests writing a 128M test file with dd at a range of different block sizes, from the default of 512 bytes to a maximum of 64M. Be warned, this script uses dd internally, so use with caution.


# Since we're dealing with dd, abort if any errors occur
set -e

if [ -e "$TEST_FILE" ]; then TEST_FILE_EXISTS=1; fi

if [ $EUID -ne 0 ]; then
  echo "NOTE: Kernel cache will not be cleared between tests without sudo. This will likely cause inaccurate results." 1>&2

# Header
PRINTF_FORMAT="%8s : %s\n"
printf "$PRINTF_FORMAT" 'block size' 'transfer rate'

# Block sizes of 512b 1K 2K 4K 8K 16K 32K 64K 128K 256K 512K 1M 2M 4M 8M 16M 32M 64M
for BLOCK_SIZE in 512 1024 2048 4096 8192 16384 32768 65536 131072 262144 524288 1048576 2097152 4194304 8388608 16777216 33554432 67108864
  # Calculate number of segments required to copy

  if [ $COUNT -le 0 ]; then
    echo "Block size of $BLOCK_SIZE estimated to require $COUNT blocks, aborting further tests."

  # Clear kernel cache to ensure more accurate test
  [ $EUID -eq 0 ] && [ -e /proc/sys/vm/drop_caches ] && echo 3 > /proc/sys/vm/drop_caches

  # Create a test file with the specified block size
  DD_RESULT=$(dd if=/dev/zero of=$TEST_FILE bs=$BLOCK_SIZE count=$COUNT conv=fsync 2>&1 1>/dev/null)

  # Extract the transfer rate from dd's STDERR output
  TRANSFER_RATE=$(echo $DD_RESULT | \grep --only-matching -E '[0-9.]+ ([MGk]?B|bytes)/s(ec)?')

  # Clean up the test file if we created one
  if [ $TEST_FILE_EXISTS -ne 0 ]; then rm $TEST_FILE; fi

  # Output the result

View on GitHub

I've only tested this script on a Debian (Ubuntu) system and on OSX Yosemite, so it will probably take some tweaking to make work on other Unix flavors.

By default the command will create a test file named dd_obs_testfile in the current directory. Alternatively, you can provide a path to a custom test file by providing a path after the script name:

$ ./ /path/to/disk/test_file

The output of the script is a list of the tested block sizes and their respective transfer rates like so:

$ ./
block size : transfer rate
       512 : 11.3 MB/s
      1024 : 22.1 MB/s
      2048 : 42.3 MB/s
      4096 : 75.2 MB/s
      8192 : 90.7 MB/s
     16384 : 101 MB/s
     32768 : 104 MB/s
     65536 : 108 MB/s
    131072 : 113 MB/s
    262144 : 112 MB/s
    524288 : 133 MB/s
   1048576 : 125 MB/s
   2097152 : 113 MB/s
   4194304 : 106 MB/s
   8388608 : 107 MB/s
  16777216 : 110 MB/s
  33554432 : 119 MB/s
  67108864 : 134 MB/s

(Note: The unit of the transfer rates will vary by OS)

To test optimal read block size, you could use more or less the same process, but instead of reading from /dev/zero and writing to the disk, you'd read from the disk and write to /dev/null. A script to do this might look like so:


# Since we're dealing with dd, abort if any errors occur
set -e

if [ -e "$TEST_FILE" ]; then TEST_FILE_EXISTS=$?; fi

# Exit if file exists
if [ -e $TEST_FILE ]; then
  echo "Test file $TEST_FILE exists, aborting."
  exit 1

if [ $EUID -ne 0 ]; then
  echo "NOTE: Kernel cache will not be cleared between tests without sudo. This will likely cause inaccurate results." 1>&2

# Create test file
echo 'Generating test file...'
dd if=/dev/urandom of=$TEST_FILE bs=$BLOCK_SIZE count=$COUNT conv=fsync > /dev/null 2>&1

# Header
PRINTF_FORMAT="%8s : %s\n"
printf "$PRINTF_FORMAT" 'block size' 'transfer rate'

# Block sizes of 512b 1K 2K 4K 8K 16K 32K 64K 128K 256K 512K 1M 2M 4M 8M 16M 32M 64M
for BLOCK_SIZE in 512 1024 2048 4096 8192 16384 32768 65536 131072 262144 524288 1048576 2097152 4194304 8388608 16777216 33554432 67108864
  # Clear kernel cache to ensure more accurate test
  [ $EUID -eq 0 ] && [ -e /proc/sys/vm/drop_caches ] && echo 3 > /proc/sys/vm/drop_caches

  # Read test file out to /dev/null with specified block size
  DD_RESULT=$(dd if=$TEST_FILE of=/dev/null bs=$BLOCK_SIZE 2>&1 1>/dev/null)

  # Extract transfer rate
  TRANSFER_RATE=$(echo $DD_RESULT | \grep --only-matching -E '[0-9.]+ ([MGk]?B|bytes)/s(ec)?')


# Clean up the test file if we created one
if [ $TEST_FILE_EXISTS -ne 0 ]; then rm $TEST_FILE; fi

View on GitHub

An important difference in this case is that the test file is a file that is written by the script. Do not point this command at an existing file or the existing file will be overwritten with zeroes!

For my particular hardware I found that 128K was the most optimal input block size on a HDD and 32K was most optimal on a SSD.

Though this answer covers most of my findings, I've run into this situation enough times that I wrote a blog post about it: You can find more specifics on the tests I performed there.

No visible cause for "Unexpected token ILLEGAL"

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

  1. In nginx.conf sendfile off

  2. uwsgi application / config --disable-sendfile

Select All checkboxes using jQuery

Use prop

$(".checkBoxClass").prop('checked', true);

or to uncheck:

$(".checkBoxClass").prop('checked', false);

$("#ckbCheckAll").click(function () {
    $(".checkBoxClass").prop('checked', $(this).prop('checked'));

Updated JSFiddle Link:

Using SELECT result in another SELECT

What you are looking for is a query with WITH clause, if your dbms supports it. Then

WITH NewScores AS (
    SELECT * 
    FROM Score  
    WHERE InsertedDate >= DATEADD(mm, -3, GETDATE())
<and the rest of your query>

Note that there is no ; in the first half. HTH.

How to pass form input value to php function

This is pretty basic, just put in the php file you want to use for processing in the element.

For example

<form action="process.php" method="post">

Then in process.php you would get the form values using $_POST['name of the variable]

How to specify a min but no max decimal using the range data annotation attribute?

If you're working with prices, I'm sure you can safely assume nothing will cost more than 1 trillion dollars.

I'd use:

[Range(0.0, 1000000000000)]

Or if you really need it, just paste in the value of Decimal.MaxValue (without the commas): 79,228,162,514,264,337,593,543,950,335

Either one of these will work well if you're not from Zimbabwe.

Cross field validation with Hibernate Validator (JSR 303)

I'm surprised this isn't available out of the box. Anyway, here is a possible solution.

I've created a class level validator, not the field level as described in the original question.

Here is the annotation code:

package com.moa.podium.util.constraints;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import javax.validation.Constraint;
import javax.validation.Payload;

@Constraint(validatedBy = MatchesValidator.class)
public @interface Matches {

  String message() default "{com.moa.podium.util.constraints.matches}";

  Class<?>[] groups() default {};

  Class<? extends Payload>[] payload() default {};

  String field();

  String verifyField();

And the validator itself:

package com.moa.podium.util.constraints;

import org.mvel2.MVEL;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class MatchesValidator implements ConstraintValidator<Matches, Object> {

  private String field;
  private String verifyField;

  public void initialize(Matches constraintAnnotation) {
    this.field = constraintAnnotation.field();
    this.verifyField = constraintAnnotation.verifyField();

  public boolean isValid(Object value, ConstraintValidatorContext context) {
    Object fieldObj = MVEL.getProperty(field, value);
    Object verifyFieldObj = MVEL.getProperty(verifyField, value);

    boolean neitherSet = (fieldObj == null) && (verifyFieldObj == null);

    if (neitherSet) {
      return true;

    boolean matches = (fieldObj != null) && fieldObj.equals(verifyFieldObj);

    if (!matches) {

    return matches;

Note that I've used MVEL to inspect the properties of the object being validated. This could be replaced with the standard reflection APIs or if it is a specific class you are validating, the accessor methods themselves.

The @Matches annotation can then be used used on a bean as follows:

@Matches(field="pass", verifyField="passRepeat")
public class AccountCreateForm {

  @Size(min=6, max=50)
  private String pass;
  private String passRepeat;


As a disclaimer, I wrote this in the last 5 minutes, so I probably haven't ironed out all the bugs yet. I'll update the answer if anything goes wrong.

Check whether a request is GET or POST


    // …

Uncaught ReferenceError: function is not defined with onclick

Make sure you are using Javascript module or not?! if using js6 modules your html events attributes won't work. in that case you must bring your function from global scope to module scope. Just add this to your javascript file: window.functionName= functionName;


<h1 onClick="functionName">some thing</h1>

Get specific object by id from array of objects in AngularJS

use $timeout and run a function to search in "results" array

app.controller("Search", function ($scope, $timeout) {
        var foo = { "results": [
             "id": 12,
             "name": "Test"
             "id": 2,
             "name": "Beispiel"
             "id": 3,
            "name": "Sample"
        ] };
        $timeout(function () {
            for (var i = 0; i < foo.results.length; i++) {
                if (foo.results[i].id=== 2) {
                    $ = foo.results[i].name;
        }, 10);


Handling 'Sequence has no elements' Exception

The value is null, you have to check why... (in addition to the implementation of the solutions proposed here)

Check the hardware Connections.

What is the difference between range and xrange functions in Python 2.X?

The difference decreases for smaller arguments to range(..) / xrange(..):

$ python -m timeit "for i in xrange(10111):" " for k in range(100):" "  pass"
10 loops, best of 3: 59.4 msec per loop

$ python -m timeit "for i in xrange(10111):" " for k in xrange(100):" "  pass"
10 loops, best of 3: 46.9 msec per loop

In this case xrange(100) is only about 20% more efficient.

Access Control Origin Header error using Axios in React Web throwing error in Chrome

$ npm install cors

After installing cors from npm add the code below to your node app file. It solved my problem.

var express = require('express')
var cors = require('cors')
var app = express()


How to get AM/PM from a datetime in PHP

Use strtotime() to make the date a UNIX timestamp.

For output, check out the various options of date().

$timestamp = strtotime("08/04/2010 22:15:00");
date("h.i A", $timestamp);

Necessary to add link tag for favicon.ico?

We can add for all devices with platform specific size

<link rel="apple-touch-icon" sizes="57x57" href="fav_icons/apple-icon-57x57.png">
<link rel="apple-touch-icon" sizes="60x60" href="fav_icons/apple-icon-60x60.png">
<link rel="apple-touch-icon" sizes="72x72" href="fav_icons/apple-icon-72x72.png">
<link rel="apple-touch-icon" sizes="76x76" href="fav_icons/apple-icon-76x76.png">
<link rel="apple-touch-icon" sizes="114x114" href="fav_icons/apple-icon-114x114.png">
<link rel="apple-touch-icon" sizes="120x120" href="fav_icons/apple-icon-120x120.png">
<link rel="apple-touch-icon" sizes="144x144" href="fav_icons/apple-icon-144x144.png">
<link rel="apple-touch-icon" sizes="152x152" href="fav_icons/apple-icon-152x152.png">
<link rel="apple-touch-icon" sizes="180x180" href="fav_icons/apple-icon-180x180.png">

<link rel="icon" type="image/png" sizes="192x192"  href="fav_icons/">
<link rel="icon" type="image/png" sizes="32x32" href="fav_icons/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="96x96" href="fav_icons/favicon-96x96.png">
<link rel="icon" type="image/png" sizes="16x16" href="fav_icons/favicon-16x16.png">

What is the alternative for ~ (user's home directory) on Windows command prompt?

You can do almost the same yourself. Open Environment Variables and click "New" Button in the "User Variables for ..." .
Variable Name: ~
Variable Value: Click "Browse Directory..." button and choose a directory which you want.

And after this, open cmd and type this:
cd %~%
. It works.

How to open CSV file in R when R says "no such file or directory"?

this work for me, accesing data from root. use double slash to access address.

dataset = read.csv('C:\\Users\\Desktop\\Machine Learning\\Data.csv')

Javascript : Send JSON Object with Ajax?

I struggled for a couple of days to find anything that would work for me as was passing multiple arrays of ids and returning a blob. Turns out if using .NET CORE I'm using 2.1, you need to use [FromBody] and as can only use once you need to create a viewmodel to hold the data.

Wrap up content like below,

var params = {
            "IDs": IDs,
            "ID2s": IDs2,
            "id": 1

In my case I had already json'd the arrays and passed the result to the function

var IDs = JsonConvert.SerializeObject(Model.Select(s => s.ID).ToArray());

Then call the XMLHttpRequest POST and stringify the object

var ajax = new XMLHttpRequest();"POST", '@Url.Action("MyAction", "MyController")', true);
ajax.responseType = "blob";
ajax.setRequestHeader("Content-Type", "application/json;charset=UTF-8");           
ajax.onreadystatechange = function () {
    if (this.readyState == 4) {
       var blob = new Blob([this.response], { type: "application/octet-stream" });
       saveAs(blob, "");


Then have a model like this

public class MyModel
    public int[] IDs { get; set; }
    public int[] ID2s { get; set; }
    public int id { get; set; }

Then pass in Action like

public async Task<IActionResult> MyAction([FromBody] MyModel model)

Use this add-on if your returning a file

<script src=""></script>

How do you detect/avoid Memory leaks in your (Unmanaged) code?

If you're using Visual Studio it might be worth looking at Bounds Checker. It's not free, but it's been incredibly helpful in finding leaks in my code. It doesn't just do memory leaks either, but also GDI resource leaks, WinAPI usage errors, and other stuff. It'll even show you where the leaked memory was initialized, making it much easier to track down the leak.

C++ int to byte array

I hope mine helps

template <typename t_int>
std::array<uint8_t, sizeof (t_int)> int2array(t_int p_value) {
    static const uint8_t _size_of (static_cast<uint8_t>(sizeof (t_int)));
    typedef std::array<uint8_t, _size_of> buffer;
    static const std::array<uint8_t, 8> _shifters = {8*0, 8*1, 8*2, 8*3, 8*4, 8*5, 8*6, 8*7};

    buffer _res;
    for (uint8_t _i=0; _i < _size_of; ++_i) {
        _res[_i] = static_cast<uint8_t>((p_value >> _shifters[_i]));
    return _res;

How to hide/show more text within a certain length (like youtube)

So much answers and all them good, but I will suggest my own, maybe it will be usefull for somebody.

We have HTML in the template:

<div class="listing-item-excerpt" id="listing-item-excerpt-<?= $task['id'] ?>">
    <?= mb_substr($txt, 0, 150) ?><span class="complete_txt"><?= mb_substr($txt, 150) ?></span>
    <a href="javascript: show_more_less(<?= $task['id'] ?>);void(0);" class="more_less_btn" data-more-txt="<?= __('... show more') ?>" data-less-txt="&nbsp;<?= __('show less') ?>" data-state="0"><?= __('... show more') ?></a>

JS function for toggling which:

function show_more_less(task_id) {

    var btn = jQuery('#listing-item-excerpt-' + task_id).find('.more_less_btn');
    var txt_container = jQuery('#listing-item-excerpt-' + task_id).find('.complete_txt');
    var state = parseInt(jQuery(btn).data('state'), 10);
    if (state === 0) {
        jQuery(btn).data('state', 1);
    } else {
        jQuery(btn).data('state', 0);

How to refresh materialized view in oracle

Best option is to use the '?' argument for the method. This way DBMS_MVIEW will choose the best way to refresh, so it'll do the fastest refresh it can for you. , and won't fail if you try something like method=>'f' when you actually need a complete refresh. :-)

from the SQL*Plus prompt:

EXEC DBMS_MVIEW.REFRESH('my_schema.my_mview', method => '?');

Escaping single quote in PHP when inserting into MySQL

For anyone finding this solution in 2015 and moving forward...

The mysql_real_escape_string() function is deprecated as of PHP 5.5.0.



This extension is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:



Failing to run jar file from command line: “no main manifest attribute”

In Eclipse: right-click on your project -> Export -> JAR file

At last page with options (when there will be no Next button active) you will see settings for Main class:. You need to set here class with main method which should be executed by default (like when JAR file will be double-clicked).

Using CMake to generate Visual Studio C++ project files

We moved our department's build chain to CMake, and we had a few internal roadbumps since other departments where using our project files and where accustomed to just importing them into their solutions. We also had some complaints about CMake not being fully integrated into the Visual Studio project/solution manager, so files had to be added manually to CMakeLists.txt; this was a major break in the workflow people were used to.

But in general, it was a quite smooth transition. We're very happy since we don't have to deal with project files anymore.

The concrete workflow for adding a new file to a project is really simple:

  1. Create the file, make sure it is in the correct place.
  2. Add the file to CMakeLists.txt.
  3. Build.

CMake 2.6 automatically reruns itself if any CMakeLists.txt files have changed (and (semi-)automatically reloads the solution/projects).

Remember that if you're doing out-of-source builds, you need to be careful not to create the source file in the build directory (since Visual Studio only knows about the build directory).

How to add a char/int to an char array in C?

Suggest replacing this:

char str[1024];
char tmp = '.';

strcat(str, tmp);

with this:

char str[1024] = {'\0'}; // set array to initial all NUL bytes
char tmp[] = "."; // create a string for the call to strcat()

strcat(str, tmp); // 

jQuery animate margin top

MarginTop should be marginTop.

How to get an array of unique values from an array containing duplicates in JavaScript?

There you go! You are welcome!

Array.prototype.unique = function()
    var tmp = {}, out = [];
    for(var i = 0, n = this.length; i < n; ++i)
        if(!tmp[this[i]]) { tmp[this[i]] = true; out.push(this[i]); }
    return out;

var a = [1,2,2,7,4,1,'a',0,6,9,'a'];
var b = a.unique();

Return multiple values from a SQL Server function

Here's the Query Analyzer template for an in-line function - it returns 2 values by default:

-- =============================================  
-- Create inline function (IF)  
-- =============================================  
   FROM   sysobjects   
   WHERE  name = N'<inline_function_name, sysname, test_function>')  
DROP FUNCTION <inline_function_name, sysname, test_function>  

CREATE FUNCTION <inline_function_name, sysname, test_function>   
(<@param1, sysname, @p1> <data_type_for_param1, , int>,   
 <@param2, sysname, @p2> <data_type_for_param2, , char>)  
RETURN SELECT   @p1 AS c1,   
        @p2 AS c2  

-- =============================================  
-- Example to execute function  
-- =============================================  
FROM <owner, , dbo>.<inline_function_name, sysname, test_function>   
    (<value_for_@param1, , 1>,   
     <value_for_@param2, , 'a'>)  

Uses for the '&quot;' entity in HTML

It is impossible, and unnecessary, to know the motivation for using &quot; in element content, but possible motives include: misunderstanding of HTML rules; use of software that generates such code (probably because its author thought it was “safer”); and misunderstanding of the meaning of &quot;: many people seem to think it produces “smart quotes” (they apparently never looked at the actual results).

Anyway, there is never any need to use &quot; in element content in HTML (XHTML or any other HTML version). There is nothing in any HTML specification that would assign any special meaning to the plain character " there.

As the question says, it has its role in attribute values, but even in them, it is mostly simpler to just use single quotes as delimiters if the value contains a double quote, e.g. alt='Greeting: "Hello, World!"' or, if you are allowed to correct errors in natural language texts, to use proper quotation marks, e.g. alt="Greeting: “Hello, World!”"

How can I use the MS JDBC driver with MS SQL Server 2008 Express?

The latest JDBC MSSQL connectivity driver can be found on JDBC 4.0

The class file should be in the classpath. If you are using eclipse you can easily do the same by doing the following -->

Right Click Project Name --> Properties --> Java Build Path --> Libraries --> Add External Jars

Also as already been pointed out by @Cheeso the correct way to access is jdbc:sqlserver://server:port;DatabaseName=dbname

Meanwhile please find a sample class for accessing MSSQL DB (2008 in my case).

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class ConnectMSSQLServer
   public void dbConnect(String db_connect_string,
            String db_userid,
            String db_password)
      try {
         Connection conn = DriverManager.getConnection(db_connect_string,
                  db_userid, db_password);
         Statement statement = conn.createStatement();
         String queryString = "select * from SampleTable";
         ResultSet rs = statement.executeQuery(queryString);
         while ( {
      } catch (Exception e) {

   public static void main(String[] args)
      ConnectMSSQLServer connServer = new ConnectMSSQLServer();
      connServer.dbConnect("jdbc:sqlserver://xx.xx.xx.xxxx:1433;databaseName=MyDBName", "DB_USER","DB_PASSWORD");

Hope this helps.

Insert node at a certain position in a linked list C++

Insert an element at very beginning position. case-1 when the list is empty. case-2 When the list is not empty.


using namespace std;

struct Node{
int data;
Node* next; //link == head =stored the address of the next node

Node* head;  //pointer to Head node with empty list

void Insert(int y);
void print();

int main(){
    head = nullptr; //empty list
    int n,y;
    cout<<"how many number do you want to enter?"<<endl;
    for (int i=0;i<n;i++){
        cout<<"Enter the number "<<i+1<<endl;

void Insert(int y){
    Node* temp = new Node(); //create dynamic memory allocation
    temp->data = y;
    temp->next = head; // temp->next = null; when list is empty
    head = temp;

void print(){
    Node* temp = head;
    cout<<"List is: "<<endl;
    while(temp!= nullptr){
        cout<<temp->data<<" ";
        temp = temp->next;

What is the .idea folder?

There is no problem in deleting this. It's not only the WebStorm IDE creating this file, but also PhpStorm and all other of JetBrains' IDEs.

It is safe to delete it but if your project is from GitLab or GitHub then you will see a warning.

Getting specified Node values from XML document

Just like you do for getting something from the CNode you also need to do for the ANode

XmlNodeList xnList = xml.SelectNodes("/Element[@*]");
foreach (XmlNode xn in xnList)
  XmlNode anode = xn.SelectSingleNode("ANode");
    if (anode!= null)
        string id = anode["ID"].InnerText;
        string date = anode["Date"].InnerText;
        XmlNodeList CNodes = xn.SelectNodes("ANode/BNode/CNode");
        foreach (XmlNode node in CNodes)
         XmlNode example = node.SelectSingleNode("Example");
         if (example != null)
            string na = example["Name"].InnerText;
            string no = example["NO"].InnerText;

How can I convert the "arguments" object to an array in JavaScript?

 function x(){
   var rest = [...arguments]; console.log(rest);return     

I tried simple destructing technique

Fastest Convert from Collection to List<T>

Since 3.5, anything inherited from System.Collection.IEnumerable has the convenient extension method OfType available.

If your collection is from ICollection or IEnumerable, you can just do this:

List<ManagementObject> managementList = ManagementObjectCollection.OfType<ManagementObject>().ToList();

Can't find any way simpler. : )

How do I make a <div> move up and down when I'm scrolling the page?

You want to apply the fixed property to the position style of the element.

position: fixed;

What browser are you working with? Not all browsers support the fixed property. Read more about who supports it, who doesn't and some work around here

Print: Entry, ":CFBundleIdentifier", Does Not Exist

I found how to solve the issue: do NOT use space in your project path!

How to uninstall / completely remove Oracle 11g (client)?

There are some more actions you should consider:

  • Remove Registry Entries for MS Distributed Transaction Coordinator (MSDTC)

    Note: on the Internet I found this step only at a single (private) page. I don't know if it is required/working or if it breaks anything on your PC.

    • Open Regedit
    • Navigate to HKEY_LOCAL_MACHINE\Software\Microsoft\MSDTC\MTxOCI
    • Add an x before each string for OracleOciLib, OracleSqlLib, and OracleXaLib
    • Navigate to HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\MSDTC\MTxOCI
    • Add an x before each string for OracleOciLib, OracleSqlLib, and OracleXaLib

    Otherwise these files, if they exist, will still be in use next time you reboot, and unable to be deleted.

  • Remove environment variable ORACLE_HOME, ORACLE_BASE, TNS_ADMIN, NLS_LANG if exist

    Check also Oracle doc to find all Oracle related environment variables, however apart from variables listed above they are very rarely used on Windows Client: Oracle Environment Variables

  • Unregister oci.dll

    • Open a command line window (Start Menu -> Run... -> cmd)
    • Enter regsvr32 /u oci.dll, resp. %windir%\SysWOW64\regsvr32 /u oci.dll

    • In some cases the file %ORACLE_HOME%\bin\oci.dll is locked and you cannot delete it. In such case rename the file (e.g. to oci.dll.x) and reboot the PC, afterwards you can delete it.

  • Remove Oracle .NET assemblies from Global Assembly Cache (GAC). You do this typically with the gacutil utility, if available on your system. Would be like this:

    gacutil /u Policy.10.1.Oracle.DataAccess
    gacutil /u Policy.10.2.Oracle.DataAccess
    gacutil /u Policy.1.102.Oracle.DataAccess
    gacutil /u Policy.1.111.Oracle.DataAccess
    gacutil /u Policy.2.102.Oracle.DataAccess
    gacutil /u Policy.2.111.Oracle.DataAccess
    gacutil /u Policy.2.112.Oracle.DataAccess
    gacutil /u Policy.2.121.Oracle.DataAccess
    gacutil /u Policy.2.122.Oracle.DataAccess
    gacutil /u Policy.4.112.Oracle.DataAccess
    gacutil /u Policy.4.121.Oracle.DataAccess
    gacutil /u Policy.4.122.Oracle.DataAccess
    gacutil /u Oracle.DataAccess
    gacutil /u Oracle.DataAccess.resources
    gacutil /u Policy.4.121.Oracle.ManagedDataAccess
    gacutil /u Policy.4.122.Oracle.ManagedDataAccess
    gacutil /u Oracle.ManagedDataAccess
    gacutil /u Oracle.ManagedDataAccess.resources
    gacutil /u Oracle.ManagedDataAccessDTC
    gacutil /u Oracle.ManagedDataAccessIOP
    gacutil /u Oracle.ManagedDataAccess.EntityFramework
    • Entry System.Data.OracleClient should not be removed, this one is installed by Microsoft - not an Oracle component!

    • Instead of gacutil /u ... you can also use OraProvCfg /action:ungac /providerpath:... if OraProvCfg is still available on your system. You may find it at %ORACLE_HOME%\\managed\x64\OraProvCfg.exe.

  • With a text editor, open XML Config file %SYSTEMROOT%\Microsoft.NET\Framework64\v4.0.30319\Config\machine.config and delete branch <oracle.manageddataaccess.client>, if existing.

    • Do the same with:


    Instead of editing the XML Config file manually you can also run (if OraProvCfg.exe is still available on your system):

    %ORACLE_HOME%\\managed\x64\OraProvCfg.exe /action:unconfig /product:odpm /frameworkversion:v4.0.30319 
    %ORACLE_HOME%\\managed\x86\OraProvCfg.exe /action:unconfig /product:odpm /frameworkversion:v4.0.30319
    %ORACLE_HOME%\\managed\x64\OraProvCfg.exe /action:unconfig /product:odp /frameworkversion:v4.0.30319 
    %ORACLE_HOME%\\managed\x86\OraProvCfg.exe /action:unconfig /product:odp /frameworkversion:v4.0.30319
  • Check following Registry Keys and delete them if existing

    HKLM\SYSTEM\CurrentControlSet\Services\EventLog\Application\Oracle Data Provider for .NET, Managed Driver
    HKLM\SYSTEM\CurrentControlSet\Services\EventLog\Application\Oracle Data Provider for .NET, Unmanaged Driver
    HKLM\SYSTEM\CurrentControlSet\Services\EventLog\Application\Oracle Provider for OLE DB
  • Delete the Inventory folder, typically C:\Program Files\Oracle\Inventory and C:\Program Files (x86)\Oracle\Inventory

  • Delete temp folders %TEMP%\deinstall\, %TEMP%\OraInstall\ and %TEMP%\CVU* (e.g %TEMP%\CVU_11. if existing.

Error:(1, 0) Plugin with id '' not found

I found the problem after one hour struggling with this error message:

I accidentally renamed the root build.gradle to filename in builde.gradle, so Android Studio didn't recognize it anymore.

Renaming it to build.gradle resolved the issue!

Download a specific tag with Git

Checking out Tags

If you want to view the versions of files a tag is pointing to, you can do a git checkout, though this puts your repository in “detached HEAD” state, which has some ill side effects:

$ git checkout 2.0.0
Note: checking out '2.0.0'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b <new-branch-name>

HEAD is now at 99ada87... Merge pull request #89 from schacon/appendix-final

$ git checkout 2.0-beta-0.1
Previous HEAD position was 99ada87... Merge pull request #89 from schacon/appendix-final
HEAD is now at df3f601... add atlas.json and cover image

In “detached HEAD” state, if you make changes and then create a commit, the tag will stay the same, but your new commit won’t belong to any branch and will be unreachable, except for by the exact commit hash. Thus, if you need to make changes—say you’re fixing a bug on an older version, for instance—you will generally want to create a branch:

$ git checkout -b version2 v2.0.0
Switched to a new branch 'version2'

If you do this and make a commit, your version2 branch will be slightly different than your v2.0.0 tag since it will move forward with your new changes, so do be careful.

Rails: Using greater than/less than with a where statement

I often have this problem with date fields (where comparison operators are very common).

To elaborate further on Mihai's answer, which I believe is a solid approach.

To the models you can add scopes like this:

scope :updated_at_less_than, -> (date_param) { 
  where(arel_table[:updated_at].lt(date_param)) }

... and then in your controller, or wherever you are using your model:

result = MyModel.updated_at_less_than('01/01/2017')

... a more complex example with joins looks like this:

result = MyParentModel.joins(:my_model).

A huge advantage of this approach is (a) it lets you compose your queries from different scopes and (b) avoids alias collisions when you join to the same table twice since arel_table will handle that part of the query generation.

Google Map API v3 — set bounds and center

The setCenter() method is still applicable for latest version of Maps API for Flash where fitBounds() does not exist.

jQuery scroll to element

For what it's worth, this is how I managed to achieve such behavior for a general element which can be inside a DIV with scrolling. In our case we don't scroll the full body, but just particular elements with overflow: auto; within a larger layout.

It creates a fake input of the height of the target element, and then puts a focus to it, and the browser will take care about the rest no matter how deep within the scrollable hierarchy you are. Works like a charm.

var $scrollTo = $('#someId'),
inputElem = $('<input type="text"></input>');

  position: 'absolute',
  width: '1px',
  height: $scrollTo.height()

How can I add NSAppTransportSecurity to my info.plist file?

XCODE 8, Swift 3: You need to add a row: **

"App transport Security Setting"

** in the info.plist inside information Property list.

Create a basic matrix in C (input by user !)

How about the following?

First ask the user for the number of rows and columns, store that in say, nrows and ncols (i.e. scanf("%d", &nrows);) and then allocate memory for a 2D array of size nrows x ncols. Thus you can have a matrix of a size specified by the user, and not fixed at some dimension you've hardcoded!

Then store the elements with for(i = 0;i < nrows; ++i) ... and display the elements in the same way except you throw in newlines after every row, i.e.

for(i = 0; i < nrows; ++i)
   for(j = 0; j < ncols ; ++j) 

Make xargs execute the command once for each line of input

@Draemon answers seems to be right with "-0" even with space in the file.

I was trying the xargs command and I found that "-0" works perfectly with "-L". even the spaces are treated (if input was null terminated ). the following is an example :

#touch "file with space"
#touch "file1"
#touch "file2"

The following will split the nulls and execute the command on each argument in the list :

 #find . -name 'file*' -print0 | xargs -0 -L1
./file with space

so -L1 will execute the argument on each null terminated character if used with "-0". To see the difference try :

 #find . -name 'file*' -print0 | xargs -0 | xargs -L1
 ./file with space ./file1 ./file2

even this will execute once :

 #find . -name 'file*' -print0  | xargs -0  | xargs -0 -L1
./file with space ./file1 ./file2

The command will execute once as the "-L" now doesn't split on null byte. you need to provide both "-0" and "-L" to work.

Can we overload the main method in Java?

Yes, main method can be overloaded. Overloaded main method has to be called from inside the "public static void main(String args[])" as this is the entry point when the class is launched by the JVM. Also overloaded main method can have any qualifier as a normal method have.

How to get all Windows service names starting with a common word?

sc queryex type= service state= all | find /i "NATION"
  • use /i for case insensitive search
  • the white space after type=is deliberate and required

Accessing clicked element in angularjs

While AngularJS allows you to get a hand on a click event (and thus a target of it) with the following syntax (note the $event argument to the setMaster function; documentation here:

function AdminController($scope) {    
  $scope.setMaster = function(obj, $event){

this is not very angular-way of solving this problem. With AngularJS the focus is on the model manipulation. One would mutate a model and let AngularJS figure out rendering.

The AngularJS-way of solving this problem (without using jQuery and without the need to pass the $event argument) would be:

<div ng-controller="AdminController">
    <ul class="list-holder">
        <li ng-repeat="section in sections" ng-class="{active : isSelected(section)}">
            <a ng-click="setMaster(section)">{{}}</a>
    {{selected | json}}

where methods in the controller would look like this:

$scope.setMaster = function(section) {
    $scope.selected = section;

$scope.isSelected = function(section) {
    return $scope.selected === section;

Here is the complete jsFiddle:

How do I connect to this localhost from another computer on the same network?

Provided both machines are in the same workgroup, open cmd.exe on the machine you want to connect to, type ipconfig and note the IP at the IPv4 Address line.

Then, on the machine you want to connect with, use http:// + the IP of the target machine.

That should do it.

Set size on background image with CSS?


If you need to make the image bigger, you must edit the image itself in an image editor.

If you use the img tag, you can change the size, but that would not give you the desired result if you need the image to be background for some other content (and it will not repeat itself like you seems to want)...

CSS3 unleash the powers

This is possible to do in CSS3 with background-size.

All modern browsers support this, so unless you need to support old browsers, this is the way to do it.
Supported browsers:
Mozilla Firefox 4.0+ (Gecko 2.0+), Microsoft Internet Explorer 9.0+, Opera 10.0+, Safari 4.1+ (webkit 532) and Chrome 3.0+.

/* Will stretch to specified width/height */
  background-size: 200px 150px;
/* Will stretch to width/height of element */
  background-size: 100% 100%;

/* width: 150px, height: auto to retain aspect ratio */
  background-size: 150px Auto;
/* height: 150px, width: auto to retain aspect ratio */
  background-size: Auto 150px;
  /* Resize to fill and retain aspect ratio.
     Will cause clipping if aspect ratio of box is different from image. */ 
  background-size: cover;
/* Resize to best fit and retain aspect ratio.
   Will cause gap if aspect ratio of box is different from image. */ 
  background-size: contain;

In particular, I like the cover and contain values that gives us new power of control that we didn't have before.


You can also use background-size: round that have a meaning in combination with repeat:

/* Resize to best fit in a whole number of times in x-direction */ 
  background-size: round auto; /* Height: auto is to keep aspect ratio */
  background-repeat: repeat;

This will adjust the image width so it fits a whole number of times in the background positioning area.

Additional note
If the size you need is static pixel size, it is still smart to physically resize the actual image. This is both to improve quality of the resize (given that your image software does a better job than the browsers), and to save bandwidth if the original image is larger than what to display.

c# search string in txt file

I worked a little bit the method that Rawling posted here to find more than one line in the same file until the end. This is what worked for me:

                foreach (var line in File.ReadLines(pathToFile))
                    if (line.Contains("CustomerEN") && current == null)
                        current = new List<string>();
                    else if (line.Contains("CustomerEN") && current != null)
                string s = String.Join(",", current);

How to count lines in a document?

wc -l <file.txt>


command | wc -l

How does System.out.print() work?

System.out is just an instance of PrintStream. You can check its JavaDoc. Its variability is based on method overloading (multiple methods with the same name, but with different parameters).

This print stream is sending its output to so called standard output.

In your question you mention a technique called variadic functions (or varargs). Unfortunately that is not supported by PrintStream#print, so you must be mistaking this with something else. However it is very easy to implement these in Java. Just check the documentation.

And if you are curious how Java knows how to concatenate non-string variables "foo" + 1 + true + myObj, it is mainly responsibility of a Java compiler.

When there is no variable involved in the concatenation, the compiler simply concatenates the string. When there is a variable involved, the concatenation is translated into StringBuilder#append chain. There is no concatenation instruction in the resulting byte code; i.e. the + operator (when talking about string concatenation) is resolved during the compilation.

All types in Java can be converted to string (int via methods in Integer class, boolean via methods in Boolean class, objects via their own #toString, ...). You can check StringBuilder's source code if you are interested.

UPDATE: I was curious myself and checked (using javap) what my example System.out.println("foo" + 1 + true + myObj) compiles into. The result:

System.out.println(new StringBuilder("foo1true").append(myObj).toString());

What are the Android SDK build-tools, platform-tools and tools? And which version should be used?

You can find details about these in this Android - Command Line Tools


SDK Tools:

  1. Android SDK Manager (sdkmanager)
  2. AVD Manager (avdmanager)
  3. Dalvik Debug Monitor Server (ddms)

Build Tools:

  1. signer
  2. proGuard
  3. zipalign
  4. jobb

Platform Tools:

  1. adb
  2. aidl, aapt, dexdump, and dx
  3. bmgr
  4. logcat