Programs & Examples On #Nsarraycontroller

on Mac OS X, NSArrayController is a bindings compatible class that manages a collection of objects

Get record counts for all tables in MySQL database

 WHERE TABLE_SCHEMA = 'your_db' 

That's all you need.

How Do I Make Glyphicons Bigger? (Change Size?)

For ex .. add class:

btn-lg - LARGE

btn-sm - SMALL

btn-xs - Very small

<button type=button class="btn btn-default btn-lg">
<span class="glyphicon glyphicon-star" aria-hidden=true></span> Star

<button type=button class="btn btn-default">
<span class="glyphicon glyphicon-star" aria-hidden=true></span>Star

 <button type=button class="btn btn-default btn-sm">
<span class="glyphicon glyphicon-star" aria-hidden=true></span> Star

<button type=button class="btn btn-default btn-xs">
<span class="glyphicon glyphicon-star" aria-hidden=true></span> Star

Ref link Bootstrap : Glyphicons Bootstrap

PHP Composer behind http proxy

If you're on Linux or Unix (including OS X), you should put this somewhere that will affect your environment:

export HTTP_PROXY_REQUEST_FULLURI=0 # or false

You can put it in /etc/profile to globally affect all users on the machine, or your own ~/.bashrc or ~/.zshrc, depending on which shell you use.

If you're on Windows, open the Environment Variables control panel, and add either a system or user environment variables with both HTTP_PROXY_REQUEST_FULLURI and HTTPS_PROXY_REQUEST_FULLURI set to 0 or false.

For other people reading this (not you, since you said you have these set up), make sure HTTP_PROXY and HTTPS_PROXY are set to the correct proxy, using the same methods. If you're on Unix/Linux/OS X, setting both upper and lowercase versions of the variable name is the most complete approach, as some things use only the lowercase version, and IIRC some use the upper case. (I'm often using a sort of hybrid environment, Cygwin on Windows, and I know for me it was important to have both, but pure Unix/Linux environments might be able to get away with just lowercase.)

If you still can't get things working after you've done all this, and you're sure you have the correct proxy address set, then look into whether your company is using a Microsoft proxy server. If so, you probably need to install Cntlm as a child proxy to connect between Composer (etc.) and the Microsoft proxy server. Google CNTLM for more information and directions on how to set it up.

Where does forever store console.log output?

This worked for me :

forever -a -o out.log -e err.log app.js

Is Spring annotation @Controller same as @Service?

If you look at the definitions of @Controller, @Service annotations, then you'll find that these are special type of @Component annotation.

public @interface Service {


public @interface Controller {

So what's the difference?


The @Controller annotation indicates that a particular class serves the role of a controller. The @Controller annotation acts as a stereotype for the annotated class, indicating its role.

What’s special about @Controller?

You cannot switch this annotation with any other like @Service or @Repository, even though they look same. The dispatcher scans the classes annotated with @Controller and detects @RequestMapping annotations within them. You can only use @RequestMapping on @Controller annotated classes.


@Services hold business logic and call method in repository layer.

What’s special about @Service?

Apart from the fact that it is used to indicate that it's holding the business logic, there’s no noticeable specialty that this annotation provides, but who knows, spring may add some additional exceptional in future.

Linked answer: What's the difference between @Component, @Repository & @Service annotations in Spring?

unknown type name 'uint8_t', MinGW


To Be Clear: If the order of your #includes matters and it is not part of your design pattern (read: you don't know why), then you need to rethink your design. Most likely, this just means you need to add the #include to the header file causing problems.

At this point, I have little interest in discussing/defending the merits of the example but will leave it up as it illustrates some nuances in the compilation process and why they result in errors.


You need to #include the stdint.h BEFORE you #include any other library interfaces that need it.


My LCD library uses uint8_t types. I wrote my library with an interface (Display.h) and an implementation (Display.c)

In display.c, I have the following includes.

#include <stdint.h>
#include <string.h>
#include <avr/io.h>
#include <Display.h>
#include <GlobalTime.h>

And this works.

However, if I re-arrange them like so:

#include <string.h>
#include <avr/io.h>
#include <Display.h>
#include <GlobalTime.h>
#include <stdint.h>

I get the error you describe. This is because Display.h needs things from stdint.h but can't access it because that information is compiled AFTER Display.h is compiled.

So move stdint.h above any library that need it and you shouldn't get the error anymore.

Starting the week on Monday with isoWeekday()

try using begin.startOf('isoWeek'); instead of begin.startOf('week');

How to interpret "loss" and "accuracy" for a machine learning model

Just to clarify the Training/Validation/Test data sets: The training set is used to perform the initial training of the model, initializing the weights of the neural network.

The validation set is used after the neural network has been trained. It is used for tuning the network's hyperparameters, and comparing how changes to them affect the predictive accuracy of the model. Whereas the training set can be thought of as being used to build the neural network's gate weights, the validation set allows fine tuning of the parameters or architecture of the neural network model. It's useful as it allows repeatable comparison of these different parameters/architectures against the same data and networks weights, to observe how parameter/architecture changes affect the predictive power of the network.

Then the test set is used only to test the predictive accuracy of the trained neural network on previously unseen data, after training and parameter/architecture selection with the training and validation data sets.

return in for loop or outside loop

Now someone told me that this is not very good programming because I use the return statement inside a loop and this would cause garbage collection to malfunction.

That's a bunch of rubbish. Everything inside the method would be cleaned up unless there were other references to it in the class or elsewhere (a reason why encapsulation is important). As a rule of thumb, it's generally better to use one return statement simply because it is easier to figure out where the method will exit.

Personally, I would write:

Boolean retVal = false;
for(int i=0; i<array.length; ++i){
    if(array[i]==valueToFind) {
        retVal = true;
        break; //Break immediately helps if you are looking through a big array
return retVal;

How to represent empty char in Java Character class

You can only re-use an existing character. e.g. \0 If you put this in a String, you will have a String with one character in it.

Say you want a char such that when you do

String s = 
char ch = ?
String s2 = s + ch; // there is not char which does this.
assert s.equals(s2);

what you have to do instead is

String s = 
char ch = MY_NULL_CHAR;
String s2 = ch == MY_NULL_CHAR ? s : s + ch;
assert s.equals(s2);

How do I format a String in an email so Outlook will print the line breaks?

Adding "\t\r\n" ( \t for TAB) instead of "\r\n" worked for me on Outlook 2010 . Note : adding 3 spaces at end of each line also do same thing but that looks like a programming hack!

Why is JsonRequestBehavior needed?

MVC defaults to DenyGet to protect you against a very specific attack involving JSON requests to improve the liklihood that the implications of allowing HTTP GET exposure are considered in advance of allowing them to occur.

This is opposed to afterwards when it might be too late.

Note: If your action method does not return sensitive data, then it should be safe to allow the get.

Further reading from my Wrox ASP.NET MVC3 book

By default, the ASP.NET MVC framework does not allow you to respond to an HTTP GET request with a JSON payload. If you need to send JSON in response to a GET, you'll need to explicitly allow the behavior by using JsonRequestBehavior.AllowGet as the second parameter to the Json method. However, there is a chance a malicious user can gain access to the JSON payload through a process known as JSON Hijacking. You do not want to return sensitive information using JSON in a GET request. For more details, see Phil's post at or this SO post.

Haack, Phil (2011). Professional ASP.NET MVC 3 (Wrox Programmer to Programmer) (Kindle Locations 6014-6020). Wrox. Kindle Edition.

Related StackOverflow question

With most recents browsers (starting with Firefox 21, Chrome 27, or IE 10), this is no more a vulnerability.

200 PORT command successful. Consider using PASV. 425 Failed to establish connection

You are using the FTP in an active mode.

Setting up the FTP in the active mode can be cumbersome nowadays due to firewalls and NATs.

It's likely because of your local firewall or NAT that the server was not able to connect back to your client to establish data transfer connection.

Or your client is not aware of its external IP address and provides an internal address instead to the server (in PORT command), which the server is obviously not able to use. But it should not be the case, as vsftpd by default rejects data transfer address not identical to source address of FTP control connection (the port_promiscuous directive).

See my article Network Configuration for Active Mode.

If possible, you should use a passive mode as it typically requires no additional setup on a client-side. That's also what the server suggested you by "Consider using PASV". The PASV is an FTP command used to enter the passive mode.

Unfortunately Windows FTP command-line client (the ftp.exe) does not support passive mode at all. It makes it pretty useless nowadays.

Use any other 3rd party Windows FTP command-line client instead. Most other support the passive mode.

For example WinSCP FTP client defaults to the passive mode and there's a guide available for converting Windows FTP script to WinSCP script.

(I'm the author of WinSCP)

Using %f with strftime() in Python to get microseconds

You can use datetime's strftime function to get this. The problem is that time's strftime accepts a timetuple that does not carry microsecond information.

from datetime import datetime"%H:%M:%S.%f")

Should do the trick!

Debug assertion failed. C++ vector subscript out of range

Regardless of how do you index the pushbacks your vector contains 10 elements indexed from 0 (0, 1, ..., 9). So in your second loop v[j] is invalid, when j is 10.

This will fix the error:

for(int j = 9;j >= 0;--j)
    cout << v[j];

In general it's better to think about indexes as 0 based, so I suggest you change also your first loop to this:

for(int i = 0;i < 10;++i)

Also, to access the elements of a container, the idiomatic approach is to use iterators (in this case: a reverse iterator):

for (vector<int>::reverse_iterator i = v.rbegin(); i != v.rend(); ++i)
    std::cout << *i << std::endl;

Count how many rows have the same value




Run an OLS regression with Pandas Data Frame

I think you can almost do exactly what you thought would be ideal, using the statsmodels package which was one of pandas' optional dependencies before pandas' version 0.20.0 (it was used for a few things in pandas.stats.)

>>> import pandas as pd
>>> import statsmodels.formula.api as sm
>>> df = pd.DataFrame({"A": [10,20,30,40,50], "B": [20, 30, 10, 40, 50], "C": [32, 234, 23, 23, 42523]})
>>> result = sm.ols(formula="A ~ B + C", data=df).fit()
>>> print(result.params)
Intercept    14.952480
B             0.401182
C             0.000352
dtype: float64
>>> print(result.summary())
                            OLS Regression Results                            
Dep. Variable:                      A   R-squared:                       0.579
Model:                            OLS   Adj. R-squared:                  0.158
Method:                 Least Squares   F-statistic:                     1.375
Date:                Thu, 14 Nov 2013   Prob (F-statistic):              0.421
Time:                        20:04:30   Log-Likelihood:                -18.178
No. Observations:                   5   AIC:                             42.36
Df Residuals:                       2   BIC:                             41.19
Df Model:                           2                                         
                 coef    std err          t      P>|t|      [95.0% Conf. Int.]
Intercept     14.9525     17.764      0.842      0.489       -61.481    91.386
B              0.4012      0.650      0.617      0.600        -2.394     3.197
C              0.0004      0.001      0.650      0.583        -0.002     0.003
Omnibus:                          nan   Durbin-Watson:                   1.061
Prob(Omnibus):                    nan   Jarque-Bera (JB):                0.498
Skew:                          -0.123   Prob(JB):                        0.780
Kurtosis:                       1.474   Cond. No.                     5.21e+04

[1] The condition number is large, 5.21e+04. This might indicate that there are
strong multicollinearity or other numerical problems.

Type List vs type ArrayList in Java

It is considered good style to store a reference to a HashSet or TreeSet in a variable of type Set.

Set<String> names = new HashSet<String>();

This way, you have to change only one line if you decide to use a TreeSet instead.

Also, methods that operate on sets should specify parameters of type Set:

public static void print(Set<String> s)

Then the method can be used for all set implementations.

In theory, we should make the same recommendation for linked lists, namely to save LinkedList references in variables of type List. However, in the Java library, the List interface is common to both the ArrayList and the LinkedList class. In particular, it has get and set methods for random access, even though these methods are very inefficient for linked lists.

You can’t write efficient code if you don’t know whether random access is efficient or not.

This is plainly a serious design error in the standard library, and I cannot recommend using the List interface for that reason.

To see just how embarrassing that error is, have a look at the source code for the binarySearch method of the Collections class. That method takes a List parameter, but binary search makes no sense for a linked list. The code then clumsily tries to discover whether the list is a linked list, and then switches to a linear search!

The Set interface and the Map interface, are well designed, and you should use them.

Java function for arrays like PHP's join()?

If you are using the Spring Framework then you have the StringUtils class:

import static org.springframework.util.StringUtils.arrayToDelimitedString;

arrayToDelimitedString(new String[] {"A", "B", "C"}, "\n");

ClassNotFoundException com.mysql.jdbc.Driver

this ans is for eclipse user......

first u check the jdbc jar file is add in Ear libraries....

if yes...then web Content->web Inf folder->lib

and past here jdbc jar file in lib folder.....

How to format numbers as currency string?

Patrick Desjardins' answer looks good, but I prefer my javascript simple. Here's a function I just wrote to take a number in and return it in currency format (minus the dollar sign)

// Format numbers to two decimals with commas
function formatDollar(num) {
    var p = num.toFixed(2).split(".");
    var chars = p[0].split("").reverse();
    var newstr = '';
    var count = 0;
    for (x in chars) {
        if(count%3 == 1 && count != 1) {
            newstr = chars[x] + ',' + newstr;
        } else {
            newstr = chars[x] + newstr;
    return newstr + "." + p[1];

How to check in Javascript if one element is contained within another

Another solution that wasn't mentioned:

Example Here

var parent = document.querySelector('.parent');

if (parent.querySelector('.child') !== null) {
    // .. it's a child

It doesn't matter whether the element is a direct child, it will work at any depth.

Alternatively, using the .contains() method:

Example Here

var parent = document.querySelector('.parent'),
    child = document.querySelector('.child');

if (parent.contains(child)) {
    // .. it's a child

Javascript : get <img> src and set as variable?

If you don't have an id on the image but have a parent div this is also a technique you can use.

<div id="myDiv"><img src=""></div>

var myVar = document.querySelectorAll('#myDiv img')[0].src

Disable Rails SQL logging in console

In case someone wants to actually knock out SQL statement logging (without changing logging level, and while keeping the logging from their AR models):

The line that writes to the log (in Rails 3.2.16, anyway) is the call to debug in lib/active_record/log_subscriber.rb:50.

That debug method is defined by ActiveSupport::LogSubscriber.

So we can knock out the logging by overwriting it like so:

module ActiveSupport
  class LogSubscriber
    def debug(*args, &block)

How do I call one constructor from another in Java?

Calling constructor from another constructor

class MyConstructorDemo extends ConstructorDemo
        this("calling another constructor");
    MyConstructorDemo(String arg)
        System.out.print("This is passed String by another constructor :"+arg);

Also you can call parent constructor by using super() call

How to unlock android phone through ADB

I had found a particular case where swiping (ADB shell input touchscreen swipe ... ) to unlock the home screen doesn't work. More exactly for Acer Z160 and Acer S57. The phones are history but still, they need to be taken into consideration by us developers. Here is the code source that solved my problem. I had made my app to start with the device. and in the "onCreate" function I had changed temporarily the lock type.

Also, just in case google drive does something to the zip file I will post fragments of that code below.


    <manifest xmlns:android=""
        <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
        <uses-permission android:name="android.permission.DISABLE_KEYGUARD" />
            <activity android:name=".MainActivity">
                    <action android:name="android.intent.action.MAIN" />
                    <category android:name="android.intent.category.LAUNCHER" />
            <receiver android:name=".ServiceStarter" android:enabled="true" android:exported="false" android:permission="android.permission.RECEIVE_BOOT_COMPLETED"
                android:directBootAware="true" tools:targetApi="n">
                    <action android:name="android.intent.action.BOOT_COMPLETED"/>
                    <category android:name="android.intent.category.DEFAULT" />

    class ServiceStarter: BroadcastReceiver() {
        override fun onReceive(context: Context?, intent: Intent?) {
            Log.d("EMY_","Calling onReceive")
             context?.let {
                 Log.i("EMY_", "Received action: ${intent!!.getAction()}, user unlocked: " + UserManagerCompat.isUserUnlocked(context))

                 val sp =it.getSharedPreferences("EMY_", Context.MODE_PRIVATE)
                 sp.edit().putString(MainActivity.MY_KEY, "M-am activat asa cum trebuie!")

                 if (intent!!.getAction().equals(Intent.ACTION_BOOT_COMPLETED)) {
                     val i = Intent(it,

class MainActivity : AppCompatActivity() {

    companion object {
        const val MY_KEY="MY_KEY"

    override fun onCreate(savedInstanceState: Bundle?) {

        val kgm = getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
        val kgl = kgm.newKeyguardLock(
        if (kgm.inKeyguardRestrictedInputMode()) {

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            requestPermissions(arrayOf(Manifest.permission.RECEIVE_BOOT_COMPLETED), 1234)

    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {

        if(1234 == requestCode )

        super.onRequestPermissionsResult(requestCode, permissions, grantResults)

    private fun afisareRezultat() {
        Log.d("EMY_","Calling afisareRezultat")
        val sp = getSharedPreferences("EMY_", Context.MODE_PRIVATE);
        val raspuns = sp.getString(MY_KEY, "Doesn't exists")
        Log.d("EMY_", "AM primit: ${raspuns}")

Can you delete multiple branches in one command with Git?

git branch  | cut -c3- | egrep "^3.2" | xargs git branch -D
  ^                ^                ^         ^ 
  |                |                |         |--- create arguments
  |                |                |              from standard input
  |                |                |
  |                |                |---your regexp 
  |                |
  |                |--- skip asterisk 
  |--- list all 


A safer version (suggested by Jakub Narebski and Jefromi), as git branch output is not meant to be used in scripting:

git for-each-ref --format="%(refname:short)" refs/heads/3.2\* | xargs git branch -D

... or the xargs-free:

git branch -D `git for-each-ref --format="%(refname:short)" refs/heads/3.2\*`

How to create NSIndexPath for TableView

Obligatory answer in Swift : NSIndexPath(forRow:row, inSection: section)

You will notice that NSIndexPath.indexPathForRow(row, inSection: section) is not available in swift and you must use the first method to construct the indexPath. Invalid postback or callback argument

My solution was to add:


after binding control after postback. it was in updatepanel with UpdateMode="Conditional" attribute.

Reading and writing to serial port in C on Linux

1) I'd add a /n after init. i.e. write( USB, "init\n", 5);

2) Double check the serial port configuration. Odds are something is incorrect in there. Just because you don't use ^Q/^S or hardware flow control doesn't mean the other side isn't expecting it.

3) Most likely: Add a "usleep(100000); after the write(). The file-descriptor is set not to block or wait, right? How long does it take to get a response back before you can call read? (It has to be received and buffered by the kernel, through system hardware interrupts, before you can read() it.) Have you considered using select() to wait for something to read()? Perhaps with a timeout?

Edited to Add:

Do you need the DTR/RTS lines? Hardware flow control that tells the other side to send the computer data? e.g.

int tmp, serialLines;

cout << "Dropping Reading DTR and RTS\n";
ioctl ( readFd, TIOCMGET, & serialLines );
serialLines &= ~TIOCM_DTR;
serialLines &= ~TIOCM_RTS;
ioctl ( readFd, TIOCMSET, & serialLines );
ioctl ( readFd, TIOCMGET, & tmp );
cout << "Reading DTR status: " << (tmp & TIOCM_DTR) << endl;
sleep (2);

cout << "Setting Reading DTR and RTS\n";
serialLines |= TIOCM_DTR;
serialLines |= TIOCM_RTS;
ioctl ( readFd, TIOCMSET, & serialLines );
ioctl ( readFd, TIOCMGET, & tmp );
cout << "Reading DTR status: " << (tmp & TIOCM_DTR) << endl;

How to create full compressed tar file using Python?

In this tar.gz file compress in open view directory In solve use os.path.basename(file_directory)

      for file in ["a.txt","b.log","c.png"]:

its use in tar.gz file compress in directory

Listing files in a specific "folder" of a AWS S3 bucket

Based on @davioooh answer. This code is worked for me.

ListObjectsRequest listObjectsRequest = new ListObjectsRequest().withBucketName("your-bucket")

mvn command not found in OSX Mavrerick

I followed brain storm's instructions and still wasn't getting different results - any new terminal windows would not recognize the mvn command. I don't know why, but breaking out the declarations in smaller chunks .bash_profile worked. As far as I can tell, I'm essentially doing the same thing he did. Here's what looks different in my .bash_profile:

export PATH J2
export PATH M2_HOME
export PATH M2

How to view file diff in git before commit

Did you try -v (or --verbose) option for git commit? It adds the diff of the commit in the message editor.

How can I switch my signed in user in Visual Studio 2013?

Start Visual Studio Tools -> Import and Export Settings -> Export selected environment settings You need to be really quick to navigate the menu before Licensing pop-up appears, (this step is optional: worst case scenario you would have to restore all the settings manually). Once in "Import and Export Settings" dialogue you can relax.

Exit Visual Studio.

From the command prompt run: devenv /resetuserdata for the particular Visual Studio version.

Safest way is to right-click on the shortcut -> Properties -> Shortcut -> Target -> copy. Final command should look something like:

"C:\Program Files (x86)\Microsoft Visual Studio NN.N\Common7\IDE\devenv.exe" /resetuserdata

Go through log-in and initial settings.

Tools -> Import and Export Settings -> Import selected environment settings to restore your original settings.

This worked when the error:

We were unable to establish the connection because it is configured for user email@address but you attempted to connect using user email@address. To connect as a different user perform a switch user operation. To connect with the configured identity just attempt the last operation again.

...has both instances of email@address identical.

When should I use Async Controllers in ASP.NET MVC?

My 5 cents:

  1. Use async/await if and only if you do an IO operation, like DB or external service webservice.
  2. Always prefer async calls to DB.
  3. Each time you query the DB.

P.S. There are exceptional cases for point 1, but you need to have a good understanding of async internals for this.

As an additional advantage, you can do few IO calls in parallel if needed:

Task task1 = FooAsync(); // launch it, but don't wait for result
Task task2 = BarAsync(); // launch bar; now both foo and bar are running
await Task.WhenAll(task1, task2); // this is better in regard to exception handling
// use task1.Result, task2.Result

col align right

Use float-right for block elements, or text-right for inline elements:

<div class="row">
     <div class="col">left</div>
     <div class="col text-right">inline content needs to be right aligned</div>
<div class="row">
      <div class="col">left</div>
      <div class="col">
          <div class="float-right">element needs to be right aligned</div>

If float-right is not working, remember that Bootstrap 4 is now flexbox, and many elements are display:flex which can prevent float-right from working.

In some cases, the utility classes like align-self-end or ml-auto work to right align elements that are inside a flexbox container like the Bootstrap 4 .row, Card or Nav. The ml-auto (margin-left:auto) is used in a flexbox element to push elements to the right.

Bootstrap 4 align right examples

How to import .py file from another directory?


import importlib.machinery

loader = importlib.machinery.SourceFileLoader('report', '/full/path/report/')
handle = loader.load_module('report')


This method can be used to import whichever way you want in a folder structure (backwards, forwards doesn't really matter, i use absolute paths just to be sure).

There's also the more normal way of importing a python module in Python3,

import importlib
module = importlib.load_module('folder.filename')

Kudos to Sebastian for spplying a similar answer for Python2:

import imp

foo = imp.load_source('', '/path/to/')

Looping through all rows in a table column, Excel-VBA

If this is in fact a ListObject table (Insert Table from the ribbon) then you can use the table's .DataBodyRange object to get the number of rows and columns. This ignores the header row.

Sub TableTest()

Dim tbl As ListObject
Dim tRows As Long
Dim tCols As Long

Set tbl = ActiveSheet.ListObjects("Table1")  '## modify to your table name.

With tbl.DataBodyRange
    tRows = .Rows.Count
    tCols = .Columns.Count
End With

MsgBox tbl.Name & " contains " & tRows & " rows and " & tCols & " columns.", vbInformation

End Sub

If you need to use the header row, instead of using tbl.DataBodyRange just use tbl.Range.

Python 3 ImportError: No module named 'ConfigParser'

For me the following command worked:

sudo python3 -m pip install mysql-connector

What is "X-Content-Type-Options=nosniff"?

Prevent content sniffing where no mimetype is sent

Configuration on Ubuntu 20.04 - apache 2.4.41:

Enable the headers module $ sudo a2enmod headers

Edit file /etc/apache2/conf-available/security.conf and add:

Header always set X-Content-Type-Options: nosniff

Restart Apache $ sudo systemctl restart apache2

$ culr -I localhost

HTTP/1.1 200 OK
Date: Fri, 23 Oct 2020 06:12:16 GMT
X-Content-Type-Options: nosniff
Last-Modified: Thu, 22 Oct 2020 08:06:06 GMT

phpmyadmin "Not Found" after install on Apache, Ubuntu

First check PhpMyAdmin is install or not. If it is installed then search PhpMyadmin folder. After search cut and paste that folder in location Computer->var->www->html->paste folder. Open browser and type localhost/phpMyAdmin and login using username and password.

Foreign keys in mongo?

How to design table like this in mongodb?

First, to clarify some naming conventions. MongoDB uses collections instead of tables.

I think there are no foreign keys!

Take the following model:

  _id: ObjectId(...),
  name: 'Jane',
  courses: [
    { course: 'bio101', mark: 85 },
    { course: 'chem101', mark: 89 }

  _id: 'bio101',
  name: 'Biology 101',
  description: 'Introduction to biology'

Clearly Jane's course list points to some specific courses. The database does not apply any constraints to the system (i.e.: foreign key constraints), so there are no "cascading deletes" or "cascading updates". However, the database does contain the correct information.

In addition, MongoDB has a DBRef standard that helps standardize the creation of these references. In fact, if you take a look at that link, it has a similar example.

How can I solve this task?

To be clear, MongoDB is not relational. There is no standard "normal form". You should model your database appropriate to the data you store and the queries you intend to run.

Confirm password validation in Angular 6

You can use this way to fulfill this requirement. I use the below method to validate the Password and Confirm Password.

To use this method you have to import FormGroup from @angular/forms library.

import { FormBuilder, Validators, FormGroup } from '@angular/forms';

FormBuilder Group:

  password    : ['', Validators.compose([Validators.required])],
  confirmPassword    : ['',  Validators.compose([Validators.required])],
{validator: this.checkPassword('password', 'confirmPassword') }

Method to Validate two fields:

 checkPassword(controlName: string, matchingControlName: string) {
    return (formGroup: FormGroup) => {
        const control = formGroup.controls[controlName];
        const matchingControl = formGroup.controls[matchingControlName];
        if (matchingControl.errors && !matchingControl.errors.mustMatch) {
            // return if another validator has already found an error on the matchingControl
        // set error on matchingControl if validation fails
        if (control.value !== matchingControl.value) {
            matchingControl.setErrors({ mustMatch: true });
            this.isPasswordSame = (matchingControl.status == 'VALID') ? true : false;
        } else {
            this.isPasswordSame = (matchingControl.status == 'VALID') ? true : false;

HTML: Here I am use personalized isPasswordSame variable you can use the inbuilt hasError or any other.

<form [formGroup]="myForm">
    <ion-label position="floating">Password</ion-label>
    <ion-input required type="text" formControlName="password" placeholder="Enter Password"></ion-input>
  <ion-label *ngIf="myForm.controls.password.valid">
      <p class="error">Please enter password!!</p>
    <ion-label position="floating">Confirm Password</ion-label>
    <ion-input required type="text" formControlName="confirmPassword" placeholder="Enter Confirm Password"></ion-input>
  <ion-label *ngIf="isPasswordSame">
      <p class="error">Password and Confrim Password must be same!!</p>

Padding a table row

You could simply add this style to the table.

table {
    border-spacing: 15px;

Regex allow digits and a single dot



\d* - any number of digits

\. - a dot

\d* - more digits.

This will match 123.456, .123, 123., but not 123

If you want the dot to be optional, in most languages (don't know about jquery) you can use


How to convert a string variable containing time to time_t type in c++?

This should work:

int hh, mm, ss;
struct tm when = {0};

sscanf_s(date, "%d:%d:%d", &hh, &mm, &ss);

when.tm_hour = hh;
when.tm_min = mm;
when.tm_sec = ss;

time_t converted;
converted = mktime(&when);

Modify as needed.

Count number of 1's in binary representation

The below method can count the number of 1s in negative numbers as well.

private static int countBits(int number)    {
    int result = 0;
    while(number != 0)  {
        result += number & 1;
        number = number >>> 1;
    return result;

However, a number like -1 is represented in binary as 11111111111111111111111111111111 and so will require a lot of shifting. If you don't want to do so many shifts for small negative numbers, another way could be as follows:

private static int countBits(int number)    {
    boolean negFlag = false;
    if(number < 0)  { 
        negFlag = true;
        number = ~number;

    int result = 0;
    while(number != 0)  {
        result += number & 1;
        number = number >> 1;
    return negFlag? (32-result): result;

What is token-based authentication?

I think it's well explained here -- quoting just the key sentences of the long article:

The general concept behind a token-based authentication system is simple. Allow users to enter their username and password in order to obtain a token which allows them to fetch a specific resource - without using their username and password. Once their token has been obtained, the user can offer the token - which offers access to a specific resource for a time period - to the remote site.

In other words: add one level of indirection for authentication -- instead of having to authenticate with username and password for each protected resource, the user authenticates that way once (within a session of limited duration), obtains a time-limited token in return, and uses that token for further authentication during the session.

Advantages are many -- e.g., the user could pass the token, once they've obtained it, on to some other automated system which they're willing to trust for a limited time and a limited set of resources, but would not be willing to trust with their username and password (i.e., with every resource they're allowed to access, forevermore or at least until they change their password).

If anything is still unclear, please edit your question to clarify WHAT isn't 100% clear to you, and I'm sure we can help you further.

Getting the last element of a list

If you do my_list[-1] this returns the last element of the list. Negative sequence indexes represent positions from the end of the array. Negative indexing means beginning from the end, -1 refers to the last item, -2 refers to the second-last item, etc.

python tuple to dict

Even more concise if you are on python 2.7:

>>> t = ((1,'a'),(2,'b'))
>>> {y:x for x,y in t}
{'a':1, 'b':2}

how to access master page control from content page

I have a helper method for this in my System.Web.UI.Page class

protected T FindControlFromMaster<T>(string name) where T : Control
     MasterPage master = this.Master;
     while (master != null)
         T control = master.FindControl(name) as T;
         if (control != null)
             return control;

         master = master.Master;
     return null;

then you can access using below code.

Label lblStatus = FindControlFromMaster<Label>("lblStatus");
    lblStatus.Text = "something";

Java: Static Class?

According to the great book "Effective Java":

Item 4: Enforce noninstantiability with a private constructor

- Attempting to enforce noninstantiability by making a class abstract does not work.

- A default constructor is generated only if a class contains no explicit constructors, so a class can be made noninstantiable by including a private constructor:

// Noninstantiable utility class
public class UtilityClass
    // Suppress default constructor for noninstantiability
    private UtilityClass() {
        throw new AssertionError();

Because the explicit constructor is private, it is inaccessible outside of the class. The AssertionError isn’t strictly required, but it provides insurance in case the constructor is accidentally invoked from within the class. It guarantees that the class will never be instantiated under any circumstances. This idiom is mildly counterintuitive, as the constructor is provided expressly so that it cannot be invoked. It is therefore wise to include a comment, as shown above.

As a side effect, this idiom also prevents the class from being subclassed. All constructors must invoke a superclass constructor, explicitly or implicitly, and a subclass would have no accessible superclass constructor to invoke.

How to convert NUM to INT in R?

Use as.integer:

x <- runif(5, 0, 100)
[1] 26.55087 37.21239 57.28534 90.82078 20.16819

[1] 26 37 57 90 20

Test for class:

xx <- as.integer(x)
 int [1:5] 26 37 57 90 20

PHP: Split string

$array = explode('.',$string);

Returns an array of split elements.

Declaring an HTMLElement Typescript

In JavaScript you declare variables or functions by using the keywords var, let or function. In TypeScript classes you declare class members or methods without these keywords followed by a colon and the type or interface of that class member.

It’s just syntax sugar, there is no difference between:

var el: HTMLElement = document.getElementById('content');


var el = document.getElementById('content');

On the other hand, because you specify the type you get all the information of your HTMLElement object.

How to store printStackTrace into a string

StackTraceElement[] stack = new Exception().getStackTrace();
String theTrace = "";
for(StackTraceElement line : stack)
   theTrace += line.toString();

How to embed image or picture in jupyter notebook, either from a local machine or from a web resource?

You mustn't use quotation marks around the name of the image files in markdown!

If you carefully read your error message, you will see the two %22 parts in the link. That is the html encoded quotation mark.

You have to change the line





It is assumed, that you have the following file structure and that you run the jupyter notebook command in the directory where the file example.ipynb (<-- contains the markdown for the image) is stored:

+-- example.ipynb
+-- img
    +-- picture.png

jQuery changing font family and font size

In my opinion, it would be a cleaner and easier solution to just set a class on the body and set the font-family in css according to that class.
don't know if that's an option in your case though.

Convert int to ASCII and back in Python

If multiple characters are bound inside a single integer/long, as was my issue:

s = '0123456789'
nchars = len(s)
# string to int or long. Type depends on nchars
x = sum(ord(s[byte])<<8*(nchars-byte-1) for byte in range(nchars))
# int or long to string
''.join(chr((x>>8*(nchars-byte-1))&0xFF) for byte in range(nchars))

Yields '0123456789' and x = 227581098929683594426425L

JavaScript: How to get parent element by selector?

Here is simple way to access parent id


will do the magic for you to access the parent div.

<body id="body">
function alertAncestorsUntilID() {
var a = document.getElementById("child").parentNode;
<div id="master">
<div id="child">Child</div>

Take the content of a list and append it to another list

You probably want


instead of


Here's the difference:

>>> a = range(5)
>>> b = range(3)
>>> c = range(2)
>>> b.append(a)
>>> b
[0, 1, 2, [0, 1, 2, 3, 4]]
>>> c.extend(a)
>>> c
[0, 1, 0, 1, 2, 3, 4]

Since list.extend() accepts an arbitrary iterable, you can also replace

for line in mylog:



How to get EditText value and display it on screen through TextView?

I didn't get the second question, maybe you can elaborate...but for your first query.

String content = edtEditText.getText().toString(); //gets you the contents of edit text
tvTextView.setText(content); //displays it in a textview..

only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices

put a int infront of the all the voxelCoord's...Like this below :

patch = numpyImage [int(voxelCoord[0]),int(voxelCoord[1])- int(voxelWidth/2):int(voxelCoord[1])+int(voxelWidth/2),int(voxelCoord[2])-int(voxelWidth/2):int(voxelCoord[2])+int(voxelWidth/2)]

Vertical Align Center in Bootstrap 4

Following bootstrap 4 classes helped me solve this

<div class="col text-center justify-content-center align-self-center">
    <img width=3rem src=".." alt="...">

If table exists drop table then create it, if it does not exist just create it


CREATE TABLE `foo` ( ... );

Try searching the MySQL documentation first if you have any other problems.

Handler "ExtensionlessUrlHandler-Integrated-4.0" has a bad module "ManagedPipelineHandler" in its module list

This error started happening to me out of nowhere last week, affecting the existing web sites on my machine. I had no luck with it trying any of the suggestions here. Eventually I removed WebDAV from IIS completely (Windows Features -> Internet Information Services -> World Wide Web Services -> Common HTTP Features -> WebDAV Publishing). I did an IIS reset after this for good measure, and my error was finally resolved.

I can only guess that a Windows update started the issue, but I can't be sure.

milliseconds to days

int days = (int) (milliseconds / 86 400 000 )

Getting Date or Time only from a DateTime Object

var currentDateTime = dateTime.Now();
var date=currentDateTime.Date;

IntelliJ IDEA "cannot resolve symbol" and "cannot resolve method"

Most likely JDK configuration is not valid, try to remove and add the JDK again as I've described in the related question here.

Increase JVM max heap size for Eclipse



Try to bump that value up!

Android ListView with onClick items

for what kind of Hell implementing Parcelable ?

he is passing to adapter String[] so

  • get item(String) at position
  • create intent
  • put it as extra
  • start activity
  • in activity get extra

to store product list you can use here HashMap (for example as STATIC object)

example class describing product:

public class Product {
    private String _name;
    private String _description;
    private int _id

    public Product(String name, String description,int id) {
        _name = name;
        _desctription = description;
        _id = id;

    public String getName() {
        return _name;

    public String getDescription() {
        return _description;

Product dell = new Product("dell","this is dell",1);

HashMap<String,Product> _hashMap = new HashMap<>();

then u pass to adapter set of keys as:

String[] productNames =  _hashMap.keySet().toArray(new String[_hashMap.size()]);

when in adapter u return view u set listener like this for example:

 public View getView(int position, View convertView, ViewGroup parent) {

     Context context = parent.getContext(); 

     String itemName = getItem(position)

     someView.setOnClikListener(new MyOnClickListener(context, itemName));


 private class MyOnClickListener implements View.OnClickListener { 

     private  String _itemName; 
     private  Context _context

     public MyOnClickListener(Context context, String itemName) {
         _context = context;
         _itemName = itemName; 

     public void onClick(View view) {
         //------listener onClick example method body ------
         Intent intent = new Intent(_context, SomeClassToHandleData.class);

then in other activity:

public void onCreate(Bundle) {

    String productName = getIntent().getExtra(key_to_product_name);
    Product product = _hashMap.get(productName);


*key_to_product_name is a public static String to serve as key for extra

ps. sorry for typo i was in hurry :) ps2. this shoud give you a idea how to do it ps3. when i will have more time i I'll add a detailed description



HTML5 : Iframe No scrolling?

In HTML5 there is no scrolling attribute because "its function is better handled by CSS" see for other changes. Well and the CSS solution:

CSS solution:

HTML4's scrolling="no" is kind of an alias of the CSS's overflow: hidden, to do so it is important to set size attributes width/height:

  width: 250px; /*or any other size*/
  height: 300px; /*or any other size*/
  overflow: hidden;

Add this class to your iframe and you're done:

<iframe src="" class="noScrolling"></iframe>

! IMPORTANT NOTE ! : overflow: hidden for <iframe> is not fully supported by all modern browsers yet(even chrome doesn't support it yet) so for now (2013) it's still better to use Transitional version and use scrolling="no" and overflow:hidden at the same time :)

UPDATE 2020: the above is still true, oveflow for iframes is still not supported by all majors

fastest way to export blobs from table into individual files

I came here looking for exporting blob into file with least effort. CLR functions is not something what I'd call least effort. Here described lazier one, using OLE Automation:

declare @init int
declare @file varbinary(max) = CONVERT(varbinary(max), N'your blob here')
declare @filepath nvarchar(4000) = N'c:\temp\you file name here.txt'

EXEC sp_OACreate 'ADODB.Stream', @init OUTPUT; -- An instace created
EXEC sp_OASetProperty @init, 'Type', 1; 
EXEC sp_OAMethod @init, 'Open'; -- Calling a method
EXEC sp_OAMethod @init, 'Write', NULL, @file; -- Calling a method
EXEC sp_OAMethod @init, 'SaveToFile', NULL, @filepath, 2; -- Calling a method
EXEC sp_OAMethod @init, 'Close'; -- Calling a method
EXEC sp_OADestroy @init; -- Closed the resources

You'll potentially need to allow to run OA stored procedures on server (and then turn it off, when you're done):

sp_configure 'show advanced options', 1;  
sp_configure 'Ole Automation Procedures', 1;  

Sending Multipart File as POST parameters with RestTemplate requests

One of our guys does something similar with the filesystemresource. try

mvm.add("file", new FileSystemResource(pUploadDTO.getFile())); 

assuming the output of your .getFile is a java File object, that should work the same as ours, which just has a File parameter.

List all employee's names and their managers by manager name using an inner join

There are three tables- Equities(coulmns: ID,ISIN) and Bond(coulmns: ID,ISIN). Third table Securities(coulmns: ID,ISIN) contains all data from Equities and Bond tables. Write SQL queries to validate below: (1) Securities table should contain all the data from Equities and Bonds tables. (2) Securities table should not contain any data other than present in Equities and Bonds tables

Remove rows not .isin('X')

You can use the method:

In [1]: df = pd.DataFrame([[1,2],[3,4]], index=['A','B'])

In [2]: df
   0  1
A  1  2
B  3  4

In [3]: L = ['A']

In [4]: x: x in L)
   0  1
A  1  2

Passing data between view controllers

Delegation is the only one solution to perform such operations when you are using .xib files. However, all previous answers are for storyboard for .xibs files. You need to use delegation. That's the only solution you can use.

Another solution is use the singleton class pattern. Initialize it once and use it in your entire app.

Setting up Gradle for api 26 (Android)

You could add google() to repositories block

allprojects {
    repositories {
        maven {
            url ''

        maven {
            url ""

get list of packages installed in Anaconda

For more conda list usage details:

usage: list [-h][-n ENVIRONMENT | -p PATH][--json] [-v] [-q]
[--show-channel-urls] [-c] [-f] [--explicit][--md5] [-e] [-r] [--no-pip][regex]

Rails Model find where not equal

In Rails 4.x (See

GroupUser.where.not(user_id: me)

In Rails 3.x


To shorten the length, you could store GroupUser.arel_table in a variable or if using inside the model GroupUser itself e.g., in a scope, you can use arel_table[:user_id] instead of GroupUser.arel_table[:user_id]

Rails 4.0 syntax credit to @jbearden's answer

How to run python script with elevated privilege on windows

I can confirm that the solution by delphifirst works and is the easiest, simplest solution to the problem of running a python script with elevated privileges.

I created a shortcut to the python executable (python.exe) and then modified the shortcut by adding my script's name after the call to python.exe. Next I checked "run as administrator" on the "compatibility tab" of the shortcut. When the shortcut is executed, you get a prompt asking permission to run the script as an administrator.

My particular python application was an installer program. The program allows installing and uninstalling another python app. In my case I created two shortcuts, one named "appname install" and the other named "appname uninstall". The only difference between the two shortcuts is the argument following the python script name. In the installer version the argument is "install". In the uninstall version the argument is "uninstall". Code in the installer script evaluates the argument supplied and calls the appropriate function (install or uninstall) as needed.

I hope my explanation helps others more quickly figure out how to run a python script with elevated privileges.

Filtering Pandas DataFrames on dates

So when loading the csv data file, we'll need to set the date column as index now as below, in order to filter data based on a range of dates. This was not needed for the now deprecated method: pd.DataFrame.from_csv().

If you just want to show the data for two months from Jan to Feb, e.g. 2020-01-01 to 2020-02-29, you can do so:

import pandas as pd
mydata = pd.read_csv('mydata.csv',index_col='date') # or its index number, e.g. index_col=[0]
mydata['2020-01-01':'2020-02-29'] # will pull all the columns
#if just need one column, e.g. Cost, can be done:

This has been tested working for Python 3.7. Hope you will find this useful.

'pip install' fails for every package ("Could not find a version that satisfies the requirement")

Support for TLS 1.0 and 1.1 was dropped for PyPI. If your system does not use a more recent version, it could explain your error.

Could you try reinstalling pip system-wide, to update your system dependencies to a newer version of TLS?

This seems to be related to Unable to install Python libraries

See Dominique Barton's answer:

Apparently pip is trying to access PyPI via HTTPS (which is encrypted and fine), but with an old (insecure) SSL version. Your system seems to be out of date. It might help if you update your packages.

On Debian-based systems I'd try:

apt-get update && apt-get upgrade python-pip

On Red Hat Linux-based systems:

yum update python-pip # (or python2-pip, at least on Red Hat Linux 7)

On Mac:

sudo easy_install -U pip

You can also try to update openssl separately.

How to add image for button in android?

Rather humorously, considering your tags, just use the ImageButton widget.

Why an interface can not implement another interface?

Interface is the class that contains an abstract method that cannot create any object.Since Interface cannot create the object and its not a pure class, Its no worth implementing it.

error: passing xxx as 'this' argument of xxx discards qualifiers

Actually the C++ standard (i.e. C++ 0x draft) says (tnx to @Xeo & @Ben Voigt for pointing that out to me):

23.2.4 Associative containers
5 For set and multiset the value type is the same as the key type. For map and multimap it is equal to pair. Keys in an associative container are immutable.
6 iterator of an associative container is of the bidirectional iterator category. For associative containers where the value type is the same as the key type, both iterator and const_iterator are constant iterators. It is unspecified whether or not iterator and const_iterator are the same type.

So VC++ 2008 Dinkumware implementation is faulty.

Old answer:

You got that error because in certain implementations of the std lib the set::iterator is the same as set::const_iterator.

For example libstdc++ (shipped with g++) has it (see here for the entire source code):

typedef typename _Rep_type::const_iterator            iterator;
typedef typename _Rep_type::const_iterator            const_iterator;

And in SGI's docs it states:

iterator       Container  Iterator used to iterate through a set.
const_iterator Container  Const iterator used to iterate through a set. (Iterator and const_iterator are the same type.)

On the other hand VC++ 2008 Express compiles your code without complaining that you're calling non const methods on set::iterators.

linux/videodev.h : no such file or directory - OpenCV on ubuntu 11.04

sudo apt-get install libv4l-dev

Editing for RH based systems :

On a Fedora 16 to install pygame 1.9.1 (in a virtualenv):

sudo yum install libv4l-devel
sudo ln -s /usr/include/libv4l1-videodev.h   /usr/include/linux/videodev.h 

How can I flush GPU memory using CUDA (physical reset is unavailable)

First type


then select the PID that you want to kill

sudo kill -9 PID

Accessing last x characters of a string in Bash

1. Generalized Substring

To generalise the question and the answer of gniourf_gniourf (as this is what I was searching for), if you want to cut a range of characters from, say, 7th from the end to 3rd from the end, you can use this syntax:

${string: -7:4}

Where 4 is the length of course (7-3).

2. Alternative using cut

In addition, while the solution of gniourf_gniourf is obviously the best and neatest, I just wanted to add an alternative solution using cut:

echo $string | cut -c $((${#string}-2))-

Here, ${#string} is the length of the string, and the "-" means cut to the end.

3. Alternative using awk

This solution instead uses the substring function of awk to select a substring which has the syntax substr(string, start, length) going to the end if the length is omitted. length($string)-2) thus picks up the last three characters.

echo $string | awk '{print substr($1,length($1)-2) }'

Angular get object from array by Id

// Used In TypeScript For Angular 4+        
const viewArray = [
          {id: 1, question: "Do you feel a connection to a higher source and have a sense of comfort knowing that you are part of something greater than yourself?", category: "Spiritual", subs: []},
          {id: 2, question: "Do you feel you are free of unhealthy behavior that impacts your overall well-being?", category: "Habits", subs: []},
          {id: 3, question: "Do you feel you have healthy and fulfilling relationships?", category: "Relationships", subs: []},
          {id: 4, question: "Do you feel you have a sense of purpose and that you have a positive outlook about yourself and life?", category: "Emotional Well-being", subs: []},
          {id: 5, question: "Do you feel you have a healthy diet and that you are fueling your body for optimal health? ", category: "Eating Habits ", subs: []},
          {id: 6, question: "Do you feel that you get enough rest and that your stress level is healthy?", category: "Relaxation ", subs: []},
          {id: 7, question: "Do you feel you get enough physical activity for optimal health?", category: "Exercise ", subs: []},
          {id: 8, question: "Do you feel you practice self-care and go to the doctor regularly?", category: "Medical Maintenance", subs: []},
          {id: 9, question: "Do you feel satisfied with your income and economic stability?", category: "Financial", subs: []},
          {id: 10, question: "Do you feel you do fun things and laugh enough in your life?", category: "Play", subs: []},
          {id: 11, question: "Do you feel you have a healthy sense of balance in this area of your life?", category: "Work-life Balance", subs: []},
          {id: 12, question: "Do you feel a sense of peace and contentment  in your home? ", category: "Home Environment", subs: []},
          {id: 13, question: "Do you feel that you are challenged and growing as a person?", category: "Intellectual Wellbeing", subs: []},
          {id: 14, question: "Do you feel content with what you see when you look in the mirror?", category: "Self-image", subs: []},
          {id: 15, question: "Do you feel engaged at work and a sense of fulfillment with your job?", category: "Work Satisfaction", subs: []}

         const arrayObj = any;
         const objectData = any;

          for (let index = 0; index < this.viewArray.length; index++) {
              this.arrayObj = this.viewArray[index];
              this.arrayObj.filter((x) => {
                if ( === id) {
                  this.objectData = x;
              console.log('Json Object Data by ID ==> ', this.objectData);

MySQL Error: #1142 - SELECT command denied to user

So the issue I ran into was this... the application I used to grant the permissions converted the Schema.TableName into a single DB statement in the wrong table, so the grant was indeed wrong, but looked correct when we did a SHOW GRANTS FOR UserName if you weren't paying very close attention to GRANT SELECT vs GRANT TABLE SELECT. Manually correcting the Grant Select on Table w/ proper escaping of Schema.Table solved my issue.

May be unrelated, but I can imagine if one client does this wrong, another might too.

Hope that's helpful.

JavaScript naming conventions

As Geoff says, what Crockford says is good.

The only exception I follow (and have seen widely used) is to use $varname to indicate a jQuery (or whatever library) object. E.g.

var footer = document.getElementById('footer');

var $footer = $('#footer');

MySQL Sum() multiple columns

SELECT student, (SUM(mark1)+SUM(mark2)+SUM(mark3)....+SUM(markn)) AS Total
 FROM your_table
 GROUP BY student

How do I truncate a .NET string?

Why not:

string NormalizeLength(string value, int maxLength)
    //check String.IsNullOrEmpty(value) and act on it. 
    return value.PadRight(maxLength).Substring(0, maxLength);

i.e. in the event value.Length < maxLength pad spaces to the end or truncate the excess.

switch case statement error: case expressions must be constant expression

It was throwing me this error when I using switch in a function with variables declared in my class:

private void ShowCalendar(final Activity context, Point p, int type) 
    switch (type) {
        case type_cat:

        case type_region:

        case type_city:


The problem was solved when I declared final to the variables in the start of the class:

final int type_cat=1, type_region=2, type_city=3;

Create an ISO date object in javascript

I solved this problem instantiating a new Date object in node.js:...

In Javascript, send the Date().toISOString() to nodejs:...

var start_date = new Date(2012, 01, 03, 8, 30);

    type: 'POST',
    data: { start_date: start_date.toISOString() },
    url: '/queryScheduleCollection',
    dataType: 'JSON'
}).done(function( response ) { ... });

Then use the ISOString to create a new Date object in nodejs:..

exports.queryScheduleCollection = function(db){
    return function(req, res){

        var start_date = new Date(req.body.start_date);

            { start_date: { $gte: start_date } }
        ).toArray( function (err,d){

Note: I'm using Express and Mongoskin.

Simulate a click on 'a' element using javascript/jquery

Code snippet underneath!

Please take a look at these documentations and examples at MDN, and you will find your answer. This is the propper way to do it I would say.

Creating and triggering events

Dispatch Event (example)

Taken from the 'Dispatch Event (example)'-HTML-link (simulate click):

function simulateClick() {

  var evt = document.createEvent("MouseEvents");

  evt.initMouseEvent("click", true, true, window,
    0, 0, 0, 0, 0, false, false, false, false, 0, null);

  var cb = document.getElementById("checkbox"); 
  var canceled = !cb.dispatchEvent(evt);

  if(canceled) {
    // A handler called preventDefault
  } else {
    // None of the handlers called preventDefault
    alert("not canceled");

This is how I would do it (2017 ..) :

Simply using MouseEvent.

function simulateClick() {

    var evt = new MouseEvent("click");

    var cb = document.getElementById("checkbox");
    var canceled = !cb.dispatchEvent(evt);

    if (canceled) {
        // A handler called preventDefault
    } else {
        // None of the handlers called preventDefault
        console.log("not canceled");

document.getElementById("button").onclick = evt => {_x000D_
function simulateClick() {_x000D_
    var evt = new MouseEvent("click");_x000D_
    var cb = document.getElementById("checkbox");_x000D_
    var canceled = !cb.dispatchEvent(evt);_x000D_
    if (canceled) {_x000D_
        // A handler called preventDefault_x000D_
    } else {_x000D_
        // None of the handlers called preventDefault_x000D_
        console.log("not canceled");_x000D_
<input type="checkbox" id="checkbox">_x000D_
<button id="button">Check it out, or not</button>

Can you do a For Each Row loop using MySQL?

In the link you provided, thats not a loop in sql...

thats a loop in programming language

they are first getting list of all distinct districts, and then for each district executing query again.

Floating divs in Bootstrap layout

From all I have read you cannot do exactly what you want without javascript. If you float left before text

<div style="float:left;">widget</div> here is some CONTENT, etc.

Your content wraps as expected. But your widget is in the top left. If you instead put the float after the content

here is some CONTENT, etc. <div style="float:left;">widget</div>

Then your content will wrap the last line to the right of the widget if the last line of content can fit to the right of the widget, otherwise no wrapping is done. To make borders and backgrounds actually include the floated area in the previous example, most people add:

here is some CONTENT, etc. <div style="float:left;">widget</div><div style="clear:both;"></div>

In your question you are using bootstrap which just adds row-fluid::after { content: ""} which resolves the border/background issue.

Moving your content up will give you the one line wrap :

  <div class="container-fluid">
  <div class="row-fluid">
    <div class="offset1 span8 pull-right">
    ... Widget 1...
    .... a lot of content ....
    <div class="span8" style="margin-left: 0;">
    ... Widget 2...



Prevent Bootstrap Modal from disappearing when clicking outside or pressing escape?

<button class='btn btn-danger fa fa-trash' data-toggle='modal' data-target='#deleteModal' data-backdrop='static' data-keyboard='false'></button>

simply add data-backdrop and data-keyboard attribute to your button on which model is open.

How can I read and parse CSV files in C++?

The first thing you need to do is make sure the file exists. To accomplish this you just need to try and open the file stream at the path. After you have opened the file stream use to see if it worked as expected, or not.

bool fileExists(string fileName)

ifstream test;;

if (
    return false;
    return true;

You must also verify that the file provided is the correct type of file. To accomplish this you need to look through the file path provided until you find the file extension. Once you have the file extension make sure that it is a .csv file.

bool verifyExtension(string filename)
int period = 0;

for (unsigned int i = 0; i < filename.length(); i++)
    if (filename[i] == '.')
        period = i;

string extension;

for (unsigned int i = period; i < filename.length(); i++)
    extension += filename[i];

if (extension == ".csv")
    return true;
    return false;

This function will return the file extension which is used later in an error message.

string getExtension(string filename)
int period = 0;

for (unsigned int i = 0; i < filename.length(); i++)
    if (filename[i] == '.')
        period = i;

string extension;

if (period != 0)
    for (unsigned int i = period; i < filename.length(); i++)
        extension += filename[i];
    extension = "NO FILE";

return extension;

This function will actually call the error checks created above and then parse through the file.

void parseFile(string fileName)
    if (fileExists(fileName) && verifyExtension(fileName))
        ifstream fs;;
        string fileCommand;

        while (fs.good())
            string temp;

            getline(fs, fileCommand, '\n');

            for (unsigned int i = 0; i < fileCommand.length(); i++)
                if (fileCommand[i] != ',')
                    temp += fileCommand[i];
                    temp += " ";

            if (temp != "\0")
                // Place your code here to run the file.
    else if (!fileExists(fileName))
        cout << "Error: The provided file does not exist: " << fileName << endl;

        if (!verifyExtension(fileName))
            if (getExtension(fileName) != "NO FILE")
                cout << "\tCheck the file extension." << endl;
                cout << "\tThere is no file in the provided path." << endl;
    else if (!verifyExtension(fileName)) 
        if (getExtension(fileName) != "NO FILE")
            cout << "Incorrect file extension provided: " << getExtension(fileName) << endl;
            cout << "There is no file in the following path: " << fileName << endl;

How to implement and do OCR in a C# project?

Here's one: (check out or for more info)

using MODI;
static void Main(string[] args)
    DocumentClass myDoc = new DocumentClass();
    myDoc.Create(@"theDocumentName.tiff"); //we work with the .tiff extension
    myDoc.OCR(MiLANGUAGES.miLANG_ENGLISH, true, true);

    foreach (Image anImage in myDoc.Images)
        Console.WriteLine(anImage.Layout.Text); //here we cout to the console.

How to convert an int array to String with toString method in Java

The toString method on an array only prints out the memory address, which you are getting. You have to loop though the array and print out each item by itself

for(int i : array) {

Get Client Machine Name in PHP

What's this "other information"? An IP address?

In PHP, you use $_SERVER['REMOTE_ADDR'] to get the IP address of the remote client, then you can use gethostbyaddr() to try and conver that IP into a hostname - but not all IPs have a reverse mapping configured.

Creating a UICollectionView programmatically

    #pragma mark -
    #pragma mark - UICollectionView Datasource and Delegates

    -(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
        return 1;

    -(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
        return Arr_AllCulturalButtler.count;

    -(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
        static NSString *coll=@"FromCulturalbutlerCollectionViewCell";
        FromCulturalbutlerCollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:coll forIndexPath:indexPath];
        cell.lbl_categoryname.text=[[Arr_AllCulturalButtler objectAtIndex:indexPath.row] Category_name];
        cell.lbl_date.text=[[Arr_AllCulturalButtler objectAtIndex:indexPath.row] event_Start_date];
        cell.lbl_location.text=[[Arr_AllCulturalButtler objectAtIndex:indexPath.row] Location_name];
        [cell.Img_Event setImageWithURL:[APPDELEGATE getURLForMediumSizeImage:[(EventObj *)[Arr_AllCulturalButtler objectAtIndex:indexPath.row] Event_image_name]] placeholderImage:nil usingActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
        cell.button_Bookmark.selected=[[Arr_AllCulturalButtler objectAtIndex:indexPath.row] Event_is_bookmarked];
        [cell.button_Bookmark addTarget:self action:@selector(btn_bookmarkClicked:) forControlEvents:UIControlEventTouchUpInside];

        return cell;
    - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath

        [self performSegueWithIdentifier:SEGUE_CULTURALBUTLER_KULTURELLIS_DETAIL sender:self];

// stroy board navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
    if ([segue.identifier isEqualToString:@"Overview_Register"])
        WDRegisterViewController *obj=(WDRegisterViewController *)[segue destinationViewController];
        obj.str_Title=@"Edit Profile";

            [self performSegueWithIdentifier:@"Overview_Measure" sender:nil];

    UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    WDPeekViewController *Peek = (WDPeekViewController *)[sb instantiateViewControllerWithIdentifier:@"WDPeekViewController"];
 [self.navigationController pushViewController:tabBarController animated:YES];

Correct way to populate an Array with a Range in Ruby

This is another way:

irb> [*1..10]

=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Python: Converting string into decimal number

If you want the result as the nearest binary floating point number use float:

result = [float(x.strip(' "')) for x in A1]

If you want the result stored exactly use Decimal instead of float:

from decimal import Decimal
result = [Decimal(x.strip(' "')) for x in A1]

Error Importing SSL certificate : Not an X.509 Certificate

Does your cacerts.pem file hold a single certificate? Since it is a PEM, have a look at it (with a text editor), it should start with


and end with


Finally, to check it is not corrupted, get hold of openssl and print its details using

openssl x509 -in cacerts.pem -text

Difference between binary tree and binary search tree

A binary tree is made of nodes, where each node contains a "left" pointer, a "right" pointer, and a data element. The "root" pointer points to the topmost node in the tree. The left and right pointers recursively point to smaller "subtrees" on either side. A null pointer represents a binary tree with no elements -- the empty tree. The formal recursive definition is: a binary tree is either empty (represented by a null pointer), or is made of a single node, where the left and right pointers (recursive definition ahead) each point to a binary tree.

A binary search tree (BST) or "ordered binary tree" is a type of binary tree where the nodes are arranged in order: for each node, all elements in its left subtree are less to the node (<), and all the elements in its right subtree are greater than the node (>).

   / \
  3   6 
 / \   \
1   4   9    

The tree shown above is a binary search tree -- the "root" node is a 5, and its left subtree nodes (1, 3, 4) are < 5, and its right subtree nodes (6, 9) are > 5. Recursively, each of the subtrees must also obey the binary search tree constraint: in the (1, 3, 4) subtree, the 3 is the root, the 1 < 3 and 4 > 3.

Watch out for the exact wording in the problems -- a "binary search tree" is different from a "binary tree".

How can I test that a variable is more than eight characters in PowerShell?

Use the length property of the [String] type:

if ($dbUserName.length -gt 8) {
    Write-Output "Please enter more than 8 characters."
    $dbUserName = Read-Host "Re-enter database username"

Please note that you have to use -gt instead of > in your if condition. PowerShell uses the following comparison operators to compare values and test conditions:

  • -eq = equals
  • -ne = not equals
  • -lt = less than
  • -gt = greater than
  • -le = less than or equals
  • -ge = greater than or equals

Copying files using rsync from remote server to local machine

From your local machine:

rsync -chavzP --stats [email protected]:/path/to/copy /path/to/local/storage

From your local machine with a non standard ssh port:

rsync -chavzP -e "ssh -p $portNumber" [email protected]:/path/to/copy /local/path

Or from the remote host, assuming you really want to work this way and your local machine is listening on SSH:

rsync -chavzP --stats /path/to/copy [email protected]:/path/to/local/storage

See man rsync for an explanation of my usual switches.

Hide options in a select list using jQuery

The problem is that Internet Explorer does not seem to support the hide and show methods for select options. I wanted to hide all options of my ddlReasonCode select which did not have the currently selected type as the value of the attribute "attType".

While the lovely Chrome was quite satisfied with:

//Hiding all options
            //Showing only the relevant options
            $("#ddlReasonCode").children("option[atttype=\"" + CurrentType + "\"]").show();

This is what IE required (kids, don't try this at CHROME :-)):

//Hiding all options
            $("#ddlReasonCode option").each(function (index, val) {
                if ($(this).is('option') && (!$(this).parent().is('span')) && ($(this).atttype != CurrentType))
            //Showing only the relevant options
            $("#ddlReasonCode option").each(function (index, val) {
                if (this.nodeName.toUpperCase() === 'OPTION') {
                    var span = $(this).parent();
                    var opt = this;
                    if ($(this).parent().is('span') && ((this).atttype == CurrentType)) {

I found that wrapping idea at

Html.Partial vs Html.RenderPartial & Html.Action vs Html.RenderAction

@Html.Partial returns view in HTML-encoded string and use same view TextWriter object. @Html.RenderPartial this method return void. @Html.RenderPartial is faster than @Html.Partial

The syntax for PartialView:

 public ActionResult AnyActionMethod
     return PartialView();

Replace one character with another in Bash

Use inline shell string replacement. Example:

foo="  "

# replace first blank only
bar=${foo/ /.}

# replace all blanks
bar=${foo// /.}

See for more details.

ios app maximum memory budget

- (float)__getMemoryUsedPer1
    struct mach_task_basic_info info;
    mach_msg_type_number_t size = MACH_TASK_BASIC_INFO;
    kern_return_t kerr = task_info(mach_task_self(), MACH_TASK_BASIC_INFO, (task_info_t)&info, &size);
    if (kerr == KERN_SUCCESS)
        float used_bytes = info.resident_size;
        float total_bytes = [NSProcessInfo processInfo].physicalMemory;
        //NSLog(@"Used: %f MB out of %f MB (%f%%)", used_bytes / 1024.0f / 1024.0f, total_bytes / 1024.0f / 1024.0f, used_bytes * 100.0f / total_bytes);
        return used_bytes / total_bytes;
    return 1;

If one will use TASK_BASIC_INFO_COUNT instead of MACH_TASK_BASIC_INFO, you will get


Page vs Window in WPF?

Pages are intended for use in Navigation applications (usually with Back and Forward buttons, e.g. Internet Explorer). Pages must be hosted in a NavigationWindow or a Frame

Windows are just normal WPF application Windows, but can host Pages via a Frame container

How to filter by IP address in Wireshark?

in our use we have to capture with host x.x.x.x. or (vlan and host x.x.x.x)

anything less will not capture? I am not sure why but that is the way it works!

Shell equality operators (=, ==, -eq)

== is a bash-specific alias for = and it performs a string (lexical) comparison instead of a numeric comparison. eq being a numeric comparison of course.

Finally, I usually prefer to use the form if [ "$a" == "$b" ]

How to get streaming url from online streaming radio station

When you go to a stream url, you get offered a file. feed this file to a parser to extract the contents out of it. the file is (usually) plain text and contains the url to play.

How to run Java program in terminal with external library JAR

  1. you can set your classpath in the in the environment variabl CLASSPATH. in linux, you can add like CLASSPATH=.:/full/path/to/the/Jars, for example ..........src/external and just run in side ......src/Report/


java Reporter

Similarily, you can set it in windows environment variables. for example, in Win7

Right click Start-->Computer then Properties-->Advanced System Setting --> Advanced -->Environment Variables in the user variables, click classPath, and Edit and add the full path of jars at the end. voila

How do you parse and process HTML/XML in PHP?

Simple HTML DOM is a great open-source parser:


It treats DOM elements in an object-oriented way, and the new iteration has a lot of coverage for non-compliant code. There are also some great functions like you'd see in JavaScript, such as the "find" function, which will return all instances of elements of that tag name.

I've used this in a number of tools, testing it on many different types of web pages, and I think it works great.

How do I fix the error "Only one usage of each socket address (protocol/network address/port) is normally permitted"?

ListenForClients is getting invoked twice (on two different threads) - once from the constructor, once from the explicit method call in Main. When two instances of the TcpListener try to listen on the same port, you get that error.

Detect viewport orientation, if orientation is Portrait display alert message advising user of instructions

David Walsh has a better and to the point approach.

// Listen for orientation changes
window.addEventListener("orientationchange", function() {
  // Announce the new orientation number
}, false);

During these changes, the window.orientation property may change. A value of 0 means portrait view, -90 means a the device is landscape rotated to the right, and 90 means the device is landscape rotated to the left.

JAVA_HOME and PATH are set but java -version still shows the old one

Updating the ~/.profile or ~/.bash_profile does not work sometimes. I just deleted JDK 6 and sourced .bash_profile.

Try running this:

sudo rm -rd jdk1.6.0_* #it may not let you delete without sudo

Then, modify/add your JAVA_HOME and PATH variables.

source ~/.bash_profile #assuming you've updated $JAVA_HOME and $PATH

finding the type of an element using jQuery

The following will return true if the element is an input:


or you can use the following to get the name of the tag:


How can I regenerate ios folder in React Native project?

Remove the ios folder first

 react-native eject 
 cd ios/ 
 pod init 
 pod install 
 cd .. 
 react-native link 
 cd ios 
 open *.xcworkspace/

HTML: can I display button text in multiple lines?

Yes, you can have it on multiple lines using the white-space css property :)

input[type="submit"] {_x000D_
    white-space: normal;_x000D_
    width: 100px;_x000D_
<input type="submit" value="Some long text that won't fit." />

add this to your element

 white-space: normal;
 width: 100px;

composer laravel create project

No this step isn't equal to downloading the by using the command composer create-project laravel/laravel laravel you actually download the laravel project as well as dependent packages so its one step ahead.

If you are using windows environment you can solve the problem by deleting the composer environment variable you created to install the composer. And this command will run properly.

FontAwesome icons not showing. Why?

I was able to get Font Awesome to work by using the all.min.css file.

How to change RGB color to HSV?

There's a C implementation here:

Should be very straightforward to convert to C#, as almost no functions are called - just calculations.

found via Google

array of string with unknown size

I think you may be looking for the StringBuilder class. If not, then the generic List class in string form:

List<string> myStringList = new List<string();
myStringList.Add("Test 1");
myStringList.Add("Test 2");

Or, if you need to be absolutely sure that the strings remain in order:

Queue<string> myStringInOriginalOrder = new Queue<string();

Remember, with the List class, the order of the items is an implementation detail and you are not guaranteed that they will stay in the same order you put them in.

How do I include image files in Django templates?

Another way to do it:

MEDIA_ROOT = '/home/USER/Projects/REPO/src/PROJECT/APP/static/media/'
MEDIA_URL = '/static/media/'

This would require you to move your media folder to a sub directory of a static folder.

Then in your template you can use:

<img class="scale-with-grid" src="{{}}"/>

Extracting jar to specified directory

There is no such option available in jar command itself. Look into the documentation:

-C dir Temporarily changes directories (cd dir) during execution of the jar command while processing the following inputfiles argument. Its operation is intended to be similar to the -C option of the UNIX tar utility. For example: jar uf foo.jar -C classes bar.class changes to the classes directory and add the bar.class from that directory to foo.jar. The following command, jar uf foo.jar -C classes . -C bin xyz.class changes to the classes directory and adds to foo.jar all files within the classes directory (without creating a classes directory in the jar file), then changes back to the original directory before changing to the bin directory to add xyz.class to foo.jar. If classes holds files bar1 and bar2, then here's what the jar file contains using jar tf foo.jar: META-INF/





How can I stream webcam video with C#?

If you want a "capture/streamer in a box" component, there are several out there as others have mentioned.

If you want to get down to the low-level control over it all, you'll need to use DirectShow as thealliedhacker points out. The best way to use DirectShow in C# is through the DirectShow.Net library - it wraps all of the DirectShow COM APIs and includes many useful shortcut functions for you.

In addition to capturing and streaming, you can also do recording, audio and video format conversions, audio and video live filters, and a whole lot of stuff.

Microsoft claims DirectShow is going away, but they have yet to release a new library or API that does everything that DirectShow provides. I suspect many of the latest things they have released are still DirectShow under the hood. Because of its status at Microsoft, there aren't a whole lot of books or references on it other than MSDN and what you can find on forums. Last year when we started a project using it, the best book on the subject - Programming Microsoft DirectShow - was out of print and going for around $350 for a used copy!

With CSS, use "..." for overflowed block of multi-lines

I have hacked around until I've managed to achieve something close to this. It comes with a few caveats:

  1. It's not pure CSS; you have to add a few HTML elements. There's however no JavaScript required.
  2. The ellipsis is right-aligned on the last line. This means that if your text isn't right-aligned or justified, there may be a noticable gap between the last visible word and the ellipsis (depending on the length of the first hidden word).
  3. The space for the ellipsis is always reserved. This means that if the text fits in the box almost precisely, it may be unnecessarily truncated (the last word is hidden, although it technically wouldn't have to).
  4. Your text needs to have a fixed background color, since we're using colored rectangles to hide the ellipsis in cases where it's not needed.

I should also note that the text will be broken at a word boundary, not a character boundary. This was deliberate (since I consider that better for longer texts), but because it's different from what text-overflow: ellipsis does, I thought I should mention it.

If you can live with these caveats, the HTML looks like this:

<div class="ellipsify">
    <div class="pre-dots"></div>
    <div class="dots">&hellip;</div>
    <!-- your text here -->
    <span class="hidedots1"></span>
    <div class="hidedots2"></div>

And this is the corresponding CSS, using the example of a 150 pixel wide box with three lines of text on a white background. It assumes you have a CSS reset or similar that sets margins and paddings to zero where necessary.

/* the wrapper */
.ellipsify {
    height: 54px;       /* 3x line height */
    width: 150px;
    overflow: hidden;
    position: relative; /* so we're a positioning parent for the dot hiders */
    background: white;

/* Used to push down .dots. Can't use absolute positioning, since that
   would stop the floating. Can't use relative positioning, since that
   would cause floating in the wrong (namely: original) place. Can't 
   change height of #dots, since it would have the full width, and
   thus cause early wrapping on all lines. */
.pre-dots {
    float: right;
    height: 36px;  /* 2x line height (one less than visible lines) */

.dots {
    float: right; /* to make the text wrap around the dots */
    clear: right; /* to push us below (not next to) .pre-dots */

/* hides the dots if the text has *exactly* 3 lines */
.hidedots1 {
    background: white;
    width: 150px;
    height: 18px;       /* line height */
    position: absolute; /* otherwise, because of the width, it'll be wrapped */

/* hides the dots if the text has *less than* 3 lines */
.hidedots2 {
    background: white; 
    width: 150px;
    height: 54px;       /* 3x line height, to ensure hiding even if empty */
    position: absolute; /* ensures we're above the dots */

The result looks like this:

image of the rendered result with different text lengths

To clarify how it works, here's the same image, except that .hidedots1 is hightlighted in red, and .hidedots2 in cyan. These are the rectangles that hide the ellipsis when there's no invisible text:

the same image as above, except that the helper elements are highlighted in color

Tested in IE9, IE8 (emulated), Chrome, Firefox, Safari, and Opera. Does not work in IE7.

How Do I Convert an Integer to a String in Excel VBA?

CStr(45) is all you need (the Convert String function)

npm ERR! network getaddrinfo ENOTFOUND

First I check whether proxy is set for me or not using this :

npm config get proxy

It returned null then I run this command

npm config set strict-ssl=false

It disable strict-ssl for that cmd session.

You can see complete list of config using this

npm config list ls -l

Create Log File in Powershell

I believe this is the simplest way of putting all what it is on the screen into a file. It is a native PS CmdLet so you don't have to change anything in yout script

Start-Transcript -Path Computer.log

Write-Host "everything will end up in Computer.log"


How to set the title of UIButton as left alignment?

For Swift 2.0:

emailBtn.contentHorizontalAlignment = UIControlContentHorizontalAlignment.Left  

This can help if any one needed.

How to use a variable in the replacement side of the Perl substitution operator?


$sub = "\\1";
$str = "hi1234";
$res = $str;
$match = "hi(.*)";
$res =~ s/$match/$1/g;

print $res

This got me the '1234'.

What is an "index out of range" exception, and how do I fix it?

Why does this error occur?

Because you tried to access an element in a collection, using a numeric index that exceeds the collection's boundaries.

The first element in a collection is generally located at index 0. The last element is at index n-1, where n is the Size of the collection (the number of elements it contains). If you attempt to use a negative number as an index, or a number that is larger than Size-1, you're going to get an error.

How indexing arrays works

When you declare an array like this:

var array = new int[6]

The first and last elements in the array are

var firstElement = array[0];
var lastElement = array[5];

So when you write:

var element = array[5];

you are retrieving the sixth element in the array, not the fifth one.

Typically, you would loop over an array like this:

for (int index = 0; index < array.Length; index++)

This works, because the loop starts at zero, and ends at Length-1 because index is no longer less than Length.

This, however, will throw an exception:

for (int index = 0; index <= array.Length; index++)

Notice the <= there? index will now be out of range in the last loop iteration, because the loop thinks that Length is a valid index, but it is not.

How other collections work

Lists work the same way, except that you generally use Count instead of Length. They still start at zero, and end at Count - 1.

for (int index = 0; i < list.Count; index++)

However, you can also iterate through a list using foreach, avoiding the whole problem of indexing entirely:

foreach (var element in list)

You cannot index an element that hasn't been added to a collection yet.

var list = new List<string>();
Console.WriteLine(list[3]);  // Throws exception.

How to reload current page without losing any form data?

You can use localStorage ( ) to save values before refreshing the page.

boundingRectWithSize for NSAttributedString returning wrong size

One thing I was noticing is that the rect that would come back from (CGRect)boundingRectWithSize:(CGSize)size options:(NSStringDrawingOptions)options attributes:(NSDictionary *)attributes context:(NSStringDrawingContext *)context would have a larger width than what I passed in. When this happened my string would be truncated. I resolved it like this:

NSString *aLongString = ...
NSInteger width = //some width;            
UIFont *font = //your font;
CGRect rect = [aLongString boundingRectWithSize:CGSizeMake(width, CGFLOAT_MAX)
                                        options:(NSStringDrawingUsesFontLeading | NSStringDrawingUsesLineFragmentOrigin)
                                     attributes:@{ NSFontAttributeName : font,
                                                   NSForegroundColorAttributeName : [UIColor whiteColor]}

if(rect.size.width > width)
    return rect.size.height + font.lineHeight;
return rect.size.height;

For some more context; I had multi line text and I was trying to find the right height to display it in. boundRectWithSize was sometimes returning a width larger than what I would specify, thus when I used my past in width and the calculated height to display my text, it would truncate. From testing when boundingRectWithSize used the wrong width the amount it would make the height short by was 1 line. So I would check if the width was greater and if so add the font's lineHeight to provide enough space to avoid truncation.

How to drop all tables in a SQL Server database?

The fasted way is:

  1. New Database Diagrams
  2. Add all table
  3. Ctrl + A to select all
  4. Right Click "Remove from Database"
  5. Ctrl + S to save
  6. Enjoy

Declare a variable as Decimal

The best way is to declare the variable as a Single or a Double depending on the precision you need. The data type Single utilizes 4 Bytes and has the range of -3.402823E38 to 1.401298E45. Double uses 8 Bytes.

You can declare as follows:

Dim decAsdf as Single


Dim decAsdf as Double

Here is an example which displays a message box with the value of the variable after calculation. All you have to do is put it in a module and run it.

Sub doubleDataTypeExample()
Dim doubleTest As Double

doubleTest = 0.0000045 * 0.005 * 0.01

MsgBox "doubleTest = " & doubleTest
End Sub

How to make vim paste from (and copy to) system's clipboard?

Based on @lis2 answer, I use a simpler configuration that will not force Insert mode at the end:

" Copy and paste
if has('clipboard') && !has('gui_running')
  vnoremap <C-c> "+y
  vnoremap <C-x> "+d
  vnoremap <C-v> "+p
  inoremap <C-v> <C-r><C-o>+

Mind that all these override default Vim mappings:

  • v_CTRL-C: stop Visual mode
  • v_CTRL-X: subtract [count] from number
  • v_CTRL-V: blockwise Visual mode
  • i_CTRL-V: insert next non-digit literally, which is also mapped to i_CTRL-Q

As an alternative, one can use keys inspired in the "yank", "delete" and "put" Vim verbs: <C-y>, <C-d> and <C-p> respectively. These would only override one default mapping:

  • i_CTRL-P: backwards search keyword for completion

How to handle AccessViolationException

You can try using AppDomain.UnhandledException and see if that lets you catch it.


Here is some more information that might be useful (it's a long read).

Angular2 *ngIf check object array length in template

Maybe slight overkill but created library ngx-if-empty-or-has-items it checks if an object, set, map or array is not empty. Maybe it will help somebody. It has the same functionality as ngIf (then, else and 'as' syntax is supported).

arrayOrObjWithData = ['1'] || {id: 1}

<h1 *ngxIfNotEmpty="arrayOrObjWithData">
  You will see it

 // store the result of async pipe in variable
 <h1 *ngxIfNotEmpty="arrayOrObjWithData$ | async as obj">


noData = [] || {}
<h1 *ngxIfHasItems="noData">
   You will NOT see it

How to put an image in div with CSS?

This answer by Jaap :

<div class="image"></div>?

and in CSS :

div.image {

you can try it on this link :

this is a link about css content

This has been tested on Chrome, firefox and Safari. (I'm on a mac, so if someone has the result on IE, tell me to add it)

Cannot attach the file *.mdf as database

I didn't read all the responses, but if your .mdf file is NOT part of the SQL installation path, like C:\Temp, then the SQL Database Engine service account(s) will not have permission to create and write to the .ldf file or even read the .mdf file.

The solution is you have to give file system permissions to the SQL Server database engine service account that runs the SQL instance service. So for me, I gave permissions full control via Windows Explorer to my C:\Temp path that contained my .mdf file for the NT Service\MSSQL$SQLEXPRESS01 and NT Service\MSSQL$MSSQL2016 accounts.

Here is a Microsoft article that details this very issue.

Declare variable in SQLite and use it

Herman's solution worked for me, but the ... had me mixed up for a bit. I'm including the demo I worked up based on his answer. The additional features in my answer include foreign key support, auto incrementing keys, and use of the last_insert_rowid() function to get the last auto generated key in a transaction.

My need for this information came up when I hit a transaction that required three foreign keys but I could only get the last one with last_insert_rowid().

PRAGMA foreign_keys = ON;   -- sqlite foreign key support is off by default
PRAGMA temp_store = 2;      -- store temp table in memory, not on disk


    FOREIGN KEY(Thing2) REFERENCES Foo(Thing1)




INSERT INTO _Variables(Key, Value)
VALUES('FooThing', last_insert_rowid());

VALUES((SELECT Value FROM _Variables WHERE Key = 'FooThing'));

DROP TABLE _Variables;


Are strongly-typed functions as parameters possible in TypeScript?

If you define function type first then it would be looked like

type Callback = (n: number) => void;

class Foo {
    save(callback: Callback) : void {        

var foo = new Foo();
var stringCallback = (result: string) : void => {

var numberCallback = (result: number) : void => {
}; //--will be showing error;

Without function type by using plain property syntax it would be:

class Foo {
    save(callback: (n: number) => void) : void {        

var foo = new Foo();
var stringCallback = (result: string) : void => {

var numberCallback = (result: number) : void => {
}; //--will be showing error;

If you want by using an interface function like c# generic delegates it would be:

interface CallBackFunc<T, U>
    (input:T): U;

class Foo {
    save(callback: CallBackFunc<number,void>) : void {        

var foo = new Foo();
var stringCallback = (result: string) : void => {

var numberCallback = (result: number) : void => {

let strCBObj:CallBackFunc<string,void> = stringCallback;
let numberCBObj:CallBackFunc<number,void> = numberCallback;; //--will be showing error;

How do I verify/check/test/validate my SSH passphrase?

ssh-keygen -y

ssh-keygen -y will prompt you for the passphrase (if there is one).

    If you input the correct passphrase, it will show you the associated public key.
    If you input the wrong passphrase, it will display load failed.
    If the key has no passphrase, it will not prompt you for a passphrase and will immediately show you the associated public key.


Create a new public/private key pair, with or without a passphrase:

$ ssh-keygen -f /tmp/my_key

Now see if you can access the key pair:

$ ssh-keygen -y -f /tmp/my_key

Following is an extended example, showing output.

Create a new public/private key pair, with or without a passphrase:

$ ssh-keygen -f /tmp/my_key
Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /tmp/my_key.
Your public key has been saved in /tmp/
The key fingerprint is:
de:24:1b:64:06:43:ca:76:ba:81:e5:f2:59:3b:81:fe [email protected]
The key's randomart image is:
+--[ RSA 2048]----+
|     .+          |
|   . . o         |
|    = . +        |
|   = + +         |
|  o = o S .      |
|   + = + *       |
|    = o o .      |
|     . .         |
|      E          |

Attempt to access the key pair by inputting the correct passphrase. Note that the public key will be shown and the exit status ($?) will be 0 to indicate success:

$ ssh-keygen -y -f /tmp/my_key
Enter passphrase:
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDBJhVYDYxXOvcQw0iJTPY64anbwSyzI58hht6xCGJ2gzGUJDIsr1NDQsclka6s0J9TNhUEBBzKvh9nTAYibXwwhIqBwJ6UwWIfA3HY13WS161CUpuKv2A/PrfK0wLFBDBlwP6WjwJNfi4NwxA21GUS/Vcm/SuMwaFid9bM2Ap4wZIahx2fxyJhmHugGUFF9qYI4yRJchaVj7TxEmquCXgVf4RVWnOSs9/MTH8YvH+wHP4WmUzsDI+uaF1SpCyQ1DpazzPWAQPgZv9R8ihOrItLXC1W6TPJkt1CLr/YFpz6vapdola8cRw6g/jTYms00Yxf2hn0/o8ORpQ9qBpcAjJN
$ echo $?

Attempt to access the key pair by inputting an incorrect passphrase. Note that the "load failed" error message will be displayed (message may differ depending on OS) and the exit status ($?) will be 1 to indicate an error:

$ ssh-keygen -y -f /tmp/my_key
Enter passphrase:
load failed
$ echo $?

Attempt to access a key pair that has no passphrase. Note that there is no prompt for the passphrase, the public key will be displayed, and the exit status ($?) will be 0 to indicate success:

$ ssh-keygen -y -f /tmp/my_key_with_no_passphrase
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDLinxx9T4HE6Brw2CvFacvFrYcOSoQUmwL4Cld4enpg8vEiN8DB2ygrhFtKVo0qMAiGWyqz9gXweXhdmAIsVXqhOJIQvD8FqddA/SMgqM++2M7GxgH68N+0V+ih7EUqf8Hb2PIeubhkQJQGzB3FjYkvRLZqE/oC1Q5nL4B1L1zDQYPSnQKneaRNG/NGIaoVwsy6gcCZeqKHywsXBOHLF4F5nf/JKqfS6ojStvzajf0eyQcUMDVhdxTN/hIfEN/HdYbOxHtwDoerv+9f6h2OUxZny1vRNivZxTa+9Qzcet4tkZWibgLmqRyFeTcWh+nOJn7K3puFB2kKoJ10q31Tq19
$ echo $?

Note that the order of arguments is important. -y must come before -f input_keyfile, else you will get the error Too many arguments..

Center Oversized Image in Div

I found this to be a more elegant solution, without flex:

.wrapper {
    overflow: hidden;
.wrapper img {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    /* height: 100%; */ /* optional */


For MySQL, you can do it like this:

CREATE TABLE New_Users   SELECT * FROM Old_Users group by ID;

how to get GET and POST variables with JQuery?

With any server-side language, you will have to emit the POST variables into javascript.


var my_post_variable = '<%= Request("post_variable") %>';

Just be careful of empty values. If the variable you attempt to emit is actually empty, you will get a javascript syntax error. If you know it's a string, you should wrap it in quotes. If it's an integer, you may want to test to see if it actually exists before writing the line to javascript.

Convert dataframe column to 1 or 0 for "true"/"false" values and assign to dataframe

@chappers solution (in the comments) works as.integer(as.logical(data.frame$

Autowiring fails: Not an managed Type

After encountering this issue and tried different method of adding the entity packaname name to EntityScan, ComponentScan etc, none of it worked.

Added the package to packageScan config in the EntityManagerFactory of the repository config. The below code gives the code based configuration as opposed to XML based ones answered above.

@Bean(name = "entityManagerFactory")
public EntityManagerFactory entityManagerFactory() {
    LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
    return emf.getObject();

How to remove non UTF-8 characters from text file

This command:

iconv -f utf-8 -t utf-8 -c file.txt

will clean up your UTF-8 file, skipping all the invalid characters.

-f is the source format
-t the target format
-c skips any invalid sequence

Git Bash is extremely slow on Windows 7 x64

I was having the same problem, in both Git Bash and Git GUI. Both programs use to run nicely, but then they randomly slowed down to a crawl, and I couldn't figure out why.

As it turns out, it was Avast. Avast has caused odd things to happen to various programs (including programs I write), so I disabled it for a second, and sure enough, Bash now runs as fast as it does on Linux. I just added the Git program files folder (C:\Program Files\Git) to the Avast exclusion list, and now it runs as fast as it does on Linux.

And yes, I realize the antivirus software was not the issue in the original post, but I'll just put this here in case it's useful to someone.

How get all values in a column using PHP?

Note that this answer is outdated! The mysql extension is no longer available out of the box as of PHP7. If you want to use the old mysql functions in PHP7, you will have to compile ext/mysql from PECL. See the other answers for more current solutions.

This would work, see more documentation here :

$result = mysql_query("SELECT names FROM Customers");
$storeArray = Array();
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
    $storeArray[] =  $row['names'];  
// now $storeArray will have all the names.

getMinutes() 0-9 - How to display two digit numbers?

Yikes these answers aren't great, even the top post upticked. Here y'go, cross-browser and cleaner int/string conversion. Plus my advice is don't use a variable name 'date' with code like date = Date(...) where you're relying heavily on language case sensitivity (it works, but risky when you're working with server/browser code in different languages with different rules). So assuming the javascript Date in a var current_date:

mins = ('0'+current_date.getMinutes()).slice(-2);

The technique is take the rightmost 2 characters (slice(-2)) of "0" prepended onto the string value of getMinutes(). So:

"0"+"12" -> "012".slice(-2) -> "12"


"0"+"1" -> "01".slice(-2) -> "01"

Which characters make a URL invalid?

Most of the existing answers here are impractical because they totally ignore the real-world usage of addresses like:

First, a digression into terminology. What are these addresses? Are they valid URLs?

Historically, the answer was "no". According to RFC 3986, from 2005, such addresses are not URIs (and therefore not URLs, since URLs are a type of URIs). Per the terminology of 2005 IETF standards, we should properly call them IRIs (Internationalized Resource Identifiers), as defined in RFC 3987, which are technically not URIs but can be converted to URIs simply by percent-encoding all non-ASCII characters in the IRI.

Per modern spec, the answer is "yes". The WHATWG Living Standard simply classifies everything that would previously be called "URIs" or "IRIs" as "URLs". This aligns the specced terminology with how normal people who haven't read the spec use the word "URL", which was one of the spec's goals.

What characters are allowed under the WHATWG Living Standard?

Per this newer meaning of "URL", what characters are allowed? In many parts of the URL, such as the query string and path, we're allowed to use arbitrary "URL units", which are

URL code points and percent-encoded bytes.

What are "URL code points"?

The URL code points are ASCII alphanumeric, U+0021 (!), U+0024 ($), U+0026 (&), U+0027 ('), U+0028 LEFT PARENTHESIS, U+0029 RIGHT PARENTHESIS, U+002A (*), U+002B (+), U+002C (,), U+002D (-), U+002E (.), U+002F (/), U+003A (:), U+003B (;), U+003D (=), U+003F (?), U+0040 (@), U+005F (_), U+007E (~), and code points in the range U+00A0 to U+10FFFD, inclusive, excluding surrogates and noncharacters.

(Note that the list of "URL code points" doesn't include %, but that %s are allowed in "URL code units" if they're part of a percent-encoding sequence.)

The only place I can spot where the spec permits the use of any character that's not in this set is in the host, where IPv6 addresses are enclosed in [ and ] characters. Everywhere else in the URL, either URL units are allowed or some even more restrictive set of characters.

What characters were allowed under the old RFCs?

For the sake of history, and since it's not explored fully elsewhere in the answers here, let's examine was allowed under the older pair of specs.

First of all, we have two types of RFC 3986 reserved characters:

  • :/?#[]@, which are part of the generic syntax for a URI defined in RFC 3986
  • !$&'()*+,;=, which aren't part of the RFC's generic syntax, but are reserved for use as syntactic components of particular URI schemes. For instance, semicolons and commas are used as part of the syntax of data URIs, and & and = are used as part of the ubiquitous ?foo=bar&qux=baz format in query strings (which isn't specified by RFC 3986).

Any of the reserved characters above can be legally used in a URI without encoding, either to serve their syntactic purpose or just as literal characters in data in some places where such use could not be misinterpreted as the character serving its syntactic purpose. (For example, although / has syntactic meaning in a URL, you can use it unencoded in a query string, because it doesn't have meaning in a query string.)

RFC 3986 also specifies some unreserved characters, which can always be used simply to represent data without any encoding:

  • abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._~

Finally, the % character itself is allowed for percent-encodings.

That leaves only the following ASCII characters that are forbidden from appearing in a URL:

  • The control characters (chars 0-1F and 7F), including new line, tab, and carriage return.
  • "<>\^`{|}

Every other character from ASCII can legally feature in a URL.

Then RFC 3987 extends that set of unreserved characters with the following unicode character ranges:

  %xA0-D7FF / %xF900-FDCF / %xFDF0-FFEF
/ %x10000-1FFFD / %x20000-2FFFD / %x30000-3FFFD
/ %x40000-4FFFD / %x50000-5FFFD / %x60000-6FFFD
/ %x70000-7FFFD / %x80000-8FFFD / %x90000-9FFFD
/ %xA0000-AFFFD / %xB0000-BFFFD / %xC0000-CFFFD
/ %xD0000-DFFFD / %xE1000-EFFFD

These block choices from the old spec seem bizarre and arbitrary given the latest Unicode block definitions; this is probably because the blocks have been added to in the decade since RFC 3987 was written.

Finally, it's perhaps worth noting that simply knowing which characters can legally appear in a URL isn't sufficient to recognise whether some given string is a legal URL or not, since some characters are only legal in particular parts of the URL. For example, the reserved characters [ and ] are legal as part of an IPv6 literal host in a URL like http://[1080::8:800:200C:417A]/foo but aren't legal in any other context, so the OP's example of[/].html is illegal.

AngularJS : Initialize service with asynchronous data

Based on Martin Atkins' solution, here is a complete, concise pure-Angular solution:

(function() {
  var initInjector = angular.injector(['ng']);
  var $http = initInjector.get('$http');
    function (response) {
      angular.module('config', []).constant('CONFIG',;

      angular.element(document).ready(function() {
          angular.bootstrap(document, ['myApp']);

This solution uses a self-executing anonymous function to get the $http service, request the config, and inject it into a constant called CONFIG when it becomes available.

Once completely, we wait until the document is ready and then bootstrap the Angular app.

This is a slight enhancement over Martin's solution, which deferred fetching the config until after the document is ready. As far as I know, there is no reason to delay the $http call for that.

Unit Testing

Note: I have discovered this solution does not work well when unit-testing when the code is included in your app.js file. The reason for this is that the above code runs immediately when the JS file is loaded. This means the test framework (Jasmine in my case) doesn't have a chance to provide a mock implementation of $http.

My solution, which I'm not completely satisfied with, was to move this code to our index.html file, so the Grunt/Karma/Jasmine unit test infrastructure does not see it.

How to get the number of threads in a Java process

I have written a program to iterate all Threads created and printing getState() of each Thread

import java.util.Set;

public class ThreadStatus {
    public static void main(String args[]) throws Exception{
        for ( int i=0; i< 5; i++){
            Thread t = new Thread(new MyThread());
        int threadCount = 0;
        Set<Thread> threadSet = Thread.getAllStackTraces().keySet();
        for ( Thread t : threadSet){
            if ( t.getThreadGroup() == Thread.currentThread().getThreadGroup()){
                System.out.println("Thread :"+t+":"+"state:"+t.getState());
        System.out.println("Thread count started by Main thread:"+threadCount);

class MyThread implements Runnable{
    public void run(){
        }catch(Exception err){


java ThreadStatus

Thread :Thread[MyThread:0,5,main]:state:TIMED_WAITING
Thread :Thread[main,5,main]:state:RUNNABLE
Thread :Thread[MyThread:1,5,main]:state:TIMED_WAITING
Thread :Thread[MyThread:4,5,main]:state:TIMED_WAITING
Thread :Thread[MyThread:2,5,main]:state:TIMED_WAITING
Thread :Thread[MyThread:3,5,main]:state:TIMED_WAITING
Thread count started by Main thread:6

If you remove below condition

if ( t.getThreadGroup() == Thread.currentThread().getThreadGroup())

You will get below threads in output too, which have been started by system.

Reference Handler, Signal Dispatcher,Attach Listener and Finalizer.

What properties can I use with

If you were to inspect the with firebug or chrome's developer tools you would see for a span element (e.g. the following properties) it will have whatever properties any element has. It depends what the target element is: HTMLSpanElement

attributes: NamedNodeMap
baseURI: "file:///C:/Test.html"
childElementCount: 0
childNodes: NodeList[1]
children: HTMLCollection[0]
classList: DOMTokenList
className: ""
clientHeight: 36
clientLeft: 1
clientTop: 1
clientWidth: 1443
contentEditable: "inherit"
dataset: DOMStringMap
dir: ""
draggable: false
firstChild: Text
firstElementChild: null
hidden: false
id: ""
innerHTML: "click"
innerText: "click"
isContentEditable: false
lang: ""
lastChild: Text
lastElementChild: null
localName: "span"
namespaceURI: ""
nextElementSibling: null
nextSibling: null
nodeName: "SPAN"
nodeType: 1
nodeValue: null
offsetHeight: 38
offsetLeft: 26
offsetParent: HTMLBodyElement
offsetTop: 62
offsetWidth: 1445
onabort: null
onbeforecopy: null
onbeforecut: null
onbeforepaste: null
onblur: null
onchange: null
onclick: null
oncontextmenu: null
oncopy: null
oncut: null
ondblclick: null
ondrag: null
ondragend: null
ondragenter: null
ondragleave: null
ondragover: null
ondragstart: null
ondrop: null
onerror: null
onfocus: null
oninput: null
oninvalid: null
onkeydown: null
onkeypress: null
onkeyup: null
onload: null
onmousedown: null
onmousemove: null
onmouseout: null
onmouseover: null
onmouseup: null
onmousewheel: null
onpaste: null
onreset: null
onscroll: null
onsearch: null
onselect: null
onselectstart: null
onsubmit: null
onwebkitfullscreenchange: null
outerHTML: "<span>click</span>"
outerText: "click"
ownerDocument: HTMLDocument
parentElement: HTMLElement
parentNode: HTMLElement
prefix: null
previousElementSibling: null
previousSibling: null
scrollHeight: 36
scrollLeft: 0
scrollTop: 0
scrollWidth: 1443
spellcheck: true
style: CSSStyleDeclaration
tabIndex: -1
tagName: "SPAN"
textContent: "click"
title: ""
webkitdropzone: ""
__proto__: HTMLSpanElement

Removing page title and date when printing web page (with CSS?)

There's a facility to have a separate style sheet for print, using

 <link type="text/css" rel="stylesheet" media="print" href="print.css">

I don't know if it does what you want though.

Custom events in jQuery?

It is an old post, but I will try to update it with a new information.

To use custom events you need to bind it to some DOM element and to trigger it. So you need to use

.on() method takes an event type and an event handling function as arguments. Optionally, it can also receive event-related data as its second argument, pushing the event handling function to the third argument. Any data that is passed will be available to the event handling function in the data property of the event object. The event handling function always receives the event object as its first argument.


.trigger() method takes an event type as its argument. Optionally, it can also take an array of values. These values will be passed to the event handling function as arguments after the event object.

The code looks like this:

$(document).on("getMsg", {
    msg: "Hello to everyone",
    time: new Date()
}, function(e, param) {
    console.log( );
    console.log( );
    console.log( param );

$( document ).trigger("getMsg", [ "Hello guys"] );

Nice explanation can be found here and here. Why exactly this can be useful? I found how to use it in this excellent explanation from twitter engineer.

P.S. In plain javascript you can do this with new CustomEvent, but beware of IE and Safari problems.

File being used by another process after using File.Create()

Try this: It works in any case, if the file doesn't exists, it will create it and then write to it. And if already exists, no problem it will open and write to it :

using (FileStream fs= new FileStream(@"File.txt",FileMode.Create,FileAccess.ReadWrite))
using (StreamWriter sw = new StreamWriter(@"File.txt")) 
    sw.WriteLine("bla bla bla"); 

string in namespace std does not name a type

You need to add:

#include <string>

In your header file.

jQuery: serialize() form and other parameters

If you want to send data with form serialize you may try this

var form= $("#formId");
    type: form.attr('method'),
    url: form.attr('action'),
    data: form.serialize()+"&variable="+otherData,
    success: function (data) {
    var result=data;


sql query to return differences between two tables

Try this :

    [First Name], [Last Name]
    [Temp Test Data] AS td EXCEPTION JOIN [Data] AS d ON 
         (d.[First Name] = td.[First Name] OR d.[Last Name] = td.[Last Name])

Much simpler to read.

In HTML5, should the main navigation be inside or outside the <header> element?

It's a little unclear whether you're asking for opinions, eg. "it's common to do xxx" or an actual rule, so I'm going to lean in the direction of rules.

The examples you cite seem based upon the examples in the spec for the nav element. Remember that the spec keeps getting tweaked and the rules are sometimes convoluted, so I'd venture many people might tend to just do what's given rather than interpret. You're showing two separate examples with different behavior, so there's only so much you can read into it. Do either of those sites also have the opposing sub/nav situation, and if so how do they handle it?

Most importantly, though, there's nothing in the spec saying either is the way to do it. One of the goals with HTML5 was to be very clear[this for comparison] about semantics, requirements, etc. so the omission is worth noting. As far as I can see, the examples are independent of each other and equally valid within their own context of layout requirements, etc.

Having the nav's source position be conditional is kind of silly(another red flag). Just pick a method and go with it.

Ignore .pyc files in git repository

Put it in .gitignore. But from the gitignore(5) man page:

  ·   If the pattern does not contain a slash /, git treats it as a shell
       glob pattern and checks for a match against the pathname relative
       to the location of the .gitignore file (relative to the toplevel of
       the work tree if not from a .gitignore file).

  ·   Otherwise, git treats the pattern as a shell glob suitable for
       consumption by fnmatch(3) with the FNM_PATHNAME flag: wildcards in
       the pattern will not match a / in the pathname. For example,
       "Documentation/*.html" matches "Documentation/git.html" but not
       "Documentation/ppc/ppc.html" or

So, either specify the full path to the appropriate *.pyc entry, or put it in a .gitignore file in any of the directories leading from the repository root (inclusive).

Convert the first element of an array to a string in PHP

Use the inbuilt function in PHP, implode(array, separator):

    $ar = array("parth","raja","nikhar");
    echo implode($ar,"/");

Result: parth/raja/nikhar

How to split a number into individual digits in c#?

You can simply do:

"123456".Select(q => new string(q,1)).ToArray();

to have an enumerable of integers, as per comment request, you can:

"123456".Select(q => int.Parse(new string(q,1))).ToArray();

It is a little weak since it assumes the string actually contains numbers.

How can I extract audio from video with ffmpeg?

ffmpeg -i sample.avi will give you the audio/video format info for your file. Make sure you have the proper libraries configured to parse the input streams. Also, make sure that the file isn't corrupt.

Select All distinct values in a column using LINQ

Interestingly enough I tried both of these in LinqPad and the variant using group from Dmitry Gribkov by appears to be quicker. (also the final distinct is not required as the result is already distinct.

My (somewhat simple) code was:

public class Pair 
    public int id {get;set;}
    public string Arb {get;set;}

void Main()

    var theList = new List<Pair>();
    var randomiser = new Random();
    for (int count = 1; count < 10000; count++)
        theList.Add(new Pair 
            id = randomiser.Next(1, 50),
            Arb = "not used"

    var timer = new Stopwatch();
    var distinct = theList.GroupBy(c => => p.First().id);

    var otherDistinct = theList.Select(p =>;

Testing if value is a function

You could simply use the typeof operator along with a ternary operator for short:

onsubmit="return typeof valid =='function' ? valid() : true;"

If it is a function we call it and return it's return value, otherwise just return true


I'm not quite sure what you really want to do, but I'll try to explain what might be happening.

When you declare your onsubmit code within your html, it gets turned into a function and thus its callable from the JavaScript "world". That means that those two methods are equivalent:

HTML: <form onsubmit="return valid();" />
JavaScript: myForm.onsubmit = function() { return valid(); };

These two will be both functions and both will be callable. You can test any of those using the typeof operator which should yeld the same result: "function".

Now if you assign a string to the "onsubmit" property via JavaScript, it will remain a string, hence not callable. Notice that if you apply the typeof operator against it, you'll get "string" instead of "function".

I hope this might clarify a few things. Then again, if you want to know if such property (or any identifier for the matter) is a function and callable, the typeof operator should do the trick. Although I'm not sure if it works properly across multiple frames.


How to create JSON object Node.js

The JavaScript Object() constructor makes an Object that you can assign members to.

myObj = new Object()
myObj.key = value;
myObj[key2] = value2;   // Alternative

preg_match(); - Unknown modifier '+'

This happened to me because I put a variable in the regex and sometimes its string value included a slash. Solution: preg_quote.

Calculate Pandas DataFrame Time Difference Between Two Columns in Hours and Minutes

Pandas timestamp differences returns a datetime.timedelta object. This can easily be converted into hours by using the *as_type* method, like so

import pandas
df = pandas.DataFrame(columns=['to','fr','ans']) = [pandas.Timestamp('2014-01-24 13:03:12.050000'), pandas.Timestamp('2014-01-27 11:57:18.240000'), pandas.Timestamp('2014-01-23 10:07:47.660000')] = [pandas.Timestamp('2014-01-26 23:41:21.870000'), pandas.Timestamp('2014-01-27 15:38:22.540000'), pandas.Timestamp('2014-01-23 18:50:41.420000')]

to yield,

0    58
1     3
2     8
dtype: float64

Constants in Kotlin -- what's a recommended way to create them?

There are a few ways you can define constants in Kotlin,

Using companion object

    companion object {
        const val ITEM1 = "item1"
        const val ITEM2 = "item2"

you can use above companion object block inside any class and define all your fields inside this block itself. But there is a problem with this approach, the documentation says,

even though the members of companion objects look like static members in other languages, at runtime those are still instance members of real objects, and can, for example, implement interfaces.

When you create your constants using companion object, and see the decompiled bytecode, you'll something like below,

  ClassName.Companion Companion = ClassName.Companion.$$INSTANCE;
  String ITEM1 = "item1";
  String ITEM2 = "item2";

  public static final class Companion {
     private static final String ITEM1 = "item1";
     public static final String ITEM2 = "item2";

     // $FF: synthetic field
     static final ClassName.Companion $$INSTANCE;

     private Companion() {

     static {
        ClassName.Companion var0 = new ClassName.Companion();
        $$INSTANCE = var0;

From here you can easily see what the documentation said, even though the members of companion objects look like static members in other languages, at runtime those are still instance members of real objects It's doing extra work than required.

Now comes another way, where we don't need to use companion object like below,

object ApiConstants {
      val ITEM1: String = "item1"

Again if you see the decompiled version of the byte code of above snippet, you'll find something like this,

public final class ApiConstants {
     private static final String ITEM1 = "item1";

     public static final ApiConstants INSTANCE;

     public final String getITEM1() {
           return ITEM1;

     private ApiConstants() {

     static {
         ApiConstants var0 = new ApiConstants();
         INSTANCE = var0;
         CONNECT_TIMEOUT = "item1";

Now if you see the above decompiled code, it's creating get method for each variable. This get method is not required at all.

To get rid of these get methods, you should use const before val like below,

object ApiConstants {
     const val ITEM1: String = "item1"

Now if you see the decompiled code of above snippet, you'll find it easier to read as it does the least background conversion for your code.

public final class ApiConstants {
    public static final String ITEM1 = "item1";
    public static final ApiConstants INSTANCE;

    private ApiConstants() {

    static {
        ApiConstants var0 = new ApiConstants();
        INSTANCE = var0;

So this is the best way to create constants.

Converting between java.time.LocalDateTime and java.util.Date

I'm not sure if this is the simplest or best way, or if there are any pitfalls, but it works:

static public LocalDateTime toLdt(Date date) {
    GregorianCalendar cal = new GregorianCalendar();
    ZonedDateTime zdt = cal.toZonedDateTime();
    return zdt.toLocalDateTime();

static public Date fromLdt(LocalDateTime ldt) {
    ZonedDateTime zdt = ZonedDateTime.of(ldt, ZoneId.systemDefault());
    GregorianCalendar cal = GregorianCalendar.from(zdt);
    return cal.getTime();

int object is not iterable?

Take your input and make sure it's a string so that it's iterable.

Then perform a list comprehension and change each value back to a number.

Now, you can do the sum of all the numbers if you want:

inp = [int(i) for i in str(input("Enter a number:"))]
print sum(inp)

Or, if you really want to see the output while it's executing:

def printadd(x,y):
    print x+y
    return x+y

inp = [int(i) for i in str(input("Enter a number:"))]

Async await in linq select

I used this code:

public static async Task<IEnumerable<TResult>> SelectAsync<TSource,TResult>(this IEnumerable<TSource> source, Func<TSource, Task<TResult>> method)
      return await Task.WhenAll(source.Select(async s => await method(s)));

like this:

var result = await sourceEnumerable.SelectAsync(async s=>await someFunction(s,other params));

"unmappable character for encoding" warning in Java

If you use eclipse (Eclipse can put utf8 code for you even you write utf8 character. You will see normal utf8 character when you programming but background will be utf8 code) ;

  1. Select Project
  2. Right click and select Properties
  3. Select Resource on Resource Panel(Top of right menu which opened after 2.)
  4. You can see in Resource Panel, Text File Encoding, select other which you want

P.S : this will ok if you static value in code. For Example String test = "IIIIIiiiiiiççççç";

Difference between int32, int, int32_t, int8 and int8_t

Between int32 and int32_t, (and likewise between int8 and int8_t) the difference is pretty simple: the C standard defines int8_t and int32_t, but does not define anything named int8 or int32 -- the latter (if they exist at all) is probably from some other header or library (most likely predates the addition of int8_t and int32_t in C99).

Plain int is quite a bit different from the others. Where int8_t and int32_t each have a specified size, int can be any size >= 16 bits. At different times, both 16 bits and 32 bits have been reasonably common (and for a 64-bit implementation, it should probably be 64 bits).

On the other hand, int is guaranteed to be present in every implementation of C, where int8_t and int32_t are not. It's probably open to question whether this matters to you though. If you use C on small embedded systems and/or older compilers, it may be a problem. If you use it primarily with a modern compiler on desktop/server machines, it probably won't be.

Oops -- missed the part about char. You'd use int8_t instead of char if (and only if) you want an integer type guaranteed to be exactly 8 bits in size. If you want to store characters, you probably want to use char instead. Its size can vary (in terms of number of bits) but it's guaranteed to be exactly one byte. One slight oddity though: there's no guarantee about whether a plain char is signed or unsigned (and many compilers can make it either one, depending on a compile-time flag). If you need to ensure its being either signed or unsigned, you need to specify that explicitly.

How to make Git "forget" about a file that was tracked but is now in .gitignore?

In my case here, I had several .lock files in several directories that I needed to remove. I ran the following and it worked without having to go into each directory to remove them:

git rm -r --cached **/*.lock

Doing this went into each folder under the 'root' of where I was at and excluded all files that matched the pattern.

Hope this helps others!

How can I find the number of arguments of a Python function?

The previously accepted answer has been deprecated as of Python 3.0. Instead of using inspect.getargspec you should now opt for the Signature class which superseded it.

Creating a Signature for the function is easy via the signature function:

from inspect import signature

def someMethod(self, arg1, kwarg1=None):

sig = signature(someMethod)

Now, you can either view its parameters quickly by string it:

str(sig)  # returns: '(self, arg1, kwarg1=None)'

or you can also get a mapping of attribute names to parameter objects via sig.parameters.

params = sig.parameters 
print(params['kwarg1']) # prints: kwarg1=20

Additionally, you can call len on sig.parameters to also see the number of arguments this function requires:

print(len(params))  # 3

Each entry in the params mapping is actually a Parameter object that has further attributes making your life easier. For example, grabbing a parameter and viewing its default value is now easily performed with:

kwarg1 = params['kwarg1']
kwarg1.default # returns: None

similarly for the rest of the objects contained in parameters.

As for Python 2.x users, while inspect.getargspec isn't deprecated, the language will soon be :-). The Signature class isn't available in the 2.x series and won't be. So you still need to work with inspect.getargspec.

As for transitioning between Python 2 and 3, if you have code that relies on the interface of getargspec in Python 2 and switching to signature in 3 is too difficult, you do have the valuable option of using inspect.getfullargspec. It offers a similar interface to getargspec (a single callable argument) in order to grab the arguments of a function while also handling some additional cases that getargspec doesn't:

from inspect import getfullargspec

def someMethod(self, arg1, kwarg1=None):

args = getfullargspec(someMethod)

As with getargspec, getfullargspec returns a NamedTuple which contains the arguments.

FullArgSpec(args=['self', 'arg1', 'kwarg1'], varargs=None, varkw=None, defaults=(None,), kwonlyargs=[], kwonlydefaults=None, annotations={})

VBA for clear value in specific range of cell and protected cell from being wash away formula

Not sure its faster with VBA - the fastest way to do it in the normal Excel programm would be:

  1. Ctrl-G
  2. A1:X50 Enter
  3. Delete

Unless you have to do this very often, entering and then triggering the VBAcode is more effort.

And in case you only want to delete formulas or values, you can insert Ctrl-G, Alt-S to select Goto Special and here select Formulas or Values.

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

//R stands for ROW and C stands for COLUMN:

//i stands for ROW and j stands for COLUMN:


int main(){

    int M[100][100];

    int R,C,i,j;

    printf("Please enter how many rows you want:\n");

    scanf("%d",& R);

    printf("Please enter how column you want:\n");

    scanf("%d",& C);

    printf("Please enter your matrix:\n");

    for(i = 0; i < R; i++){

        for(j = 0; j < C; j++){

            scanf("%d", &M[i][j]);



    for(i = 0; i < R; i++){

        for(j = 0; j < C; j++){

            printf("%d\t", M[i][j]);




   return 0;

What does "if (" mean?

First thing, you don't need to write

ResultSet rs = stmt.executeQuery(sql);

just write

ResultSet rs = stmt.executeQuery();

The above mentioned syntax is used for Statements not for PreparedStatement.

Second thing, checks if the result set contains any values or not. It returns a boolean value as well as it moves the cursor to the first value in the result set because initially it is at BEFORE FIRST Position. So if you want to access first value in result set, you need to write

Get raw POST body in Python Flask regardless of Content-Type header is the stream of raw data passed to the application by the WSGI server. No parsing is done when reading it, although you usually want request.get_data() instead.

data =

The stream will be empty if it was previously read by or another attribute.

Receiving JSON data back from HTTP request

I think the shortest way is:

var client = new HttpClient();
string reqUrl = $"{ProdId}";
var prodResp = await client.GetAsync(reqUrl);
if (!prodResp.IsSuccessStatusCode){
var prods = await prodResp.Content.ReadAsAsync<Products>();

Is there an equivalent method to C's scanf in Java?

There is not a pure scanf replacement in standard Java, but you could use a java.util.Scanner for the same problems you would use scanf to solve.