Programs & Examples On #System setting

How to create a listbox in HTML without allowing multiple selection?

Just use the size attribute:

<select name="sometext" size="5">

To clarify, adding the size attribute did not remove the multiple selection.

The single selection works because you removed the multiple="multiple" attribute.

Adding the size="5" attribute is still a good idea, it means that at least 5 lines must be displayed. See the full reference here

How to scanf only integer?

A possible solution is to think about it backwards: Accept a float as input and reject the input if the float is not an integer:

int n;
float f;
printf("Please enter an integer: ");
while(scanf("%f",&f)!=1 || (int)f != f)
n = f;

Though this does allow the user to enter something like 12.0, or 12e0, etc.

How to hide a mobile browser's address bar?

The easiest way to archive browser address bar hiding on page scroll is to add "display": "standalone", to manifest.json file.

Change a web.config programmatically with C# (.NET)

Since web.config file is xml file you can open web.config using xmldocument class. Get the node from that xml file that you want to update and then save xml file.

here is URL that explains in more detail how you can update web.config file programmatically.

Note: if you make any changes to web.config, ASP.NET detects that changes and it will reload your application(recycle application pool) and effect of that is data kept in Session, Application, and Cache will be lost (assuming session state is InProc and not using a state server or database).

Can I convert a C# string value to an escaped string literal

There's a method for this in Roslyn's Microsoft.CodeAnalysis.CSharp package on nuget :

    private static string ToLiteral(string valueTextForCompiler)
        return Microsoft.CodeAnalysis.CSharp.SymbolDisplay.FormatLiteral(valueTextForCompiler, false);

Obviously this didn't exist at the time of the original question, but might help people who end up here from Google.

Run ssh and immediately execute command

This isn't quite what you're looking for, but I've found it useful in similar circumstances.

I recently added the following to my $HOME/.bashrc (something similar should be possible with shells other than bash):

if [ -f $HOME/.add-screen-to-history ] ; then
    history -s 'screen -dr'

I keep a screen session running on one particular machine, and I've had problems with ssh connections to that machine being dropped, requiring me to re-run screen -dr every time I reconnect.

With that addition, and after creating that (empty) file in my home directory, I automatically have the screen -dr command in my history when my shell starts. After reconnecting, I can just type Control-P Enter and I'm back in my screen session -- or I can ignore it. It's flexible, but not quite automatic, and in your case it's easier than typing tmux list-sessions.

You might want to make the history -s command unconditional.

This does require updating your $HOME/.bashrc on each of the target systems, which might or might not make it unsuitable for your purposes.

How to compare two java objects

1) == evaluates reference equality in this case
2) im not too sure about the equals, but why not simply overriding the compare method and plant it inside MyClass?

How to use a Java8 lambda to sort a stream in reverse order?

This can easily be done using Java 8 and the use of a reversed Comparator.

I have created a list of files from a directory, which I display unsorted, sorted and reverse sorted using a simple Comparator for the sort and then calling reversed() on it to get the reversed version of that Comparator.

See code below:

package test;

import java.util.Arrays;
import java.util.Comparator;
import java.util.Date;
import java.util.List;

public class SortTest {
    public static void main(String... args) {
        File directory = new File("C:/Media");
        File[] files = directory.listFiles();
        List<File> filesList = Arrays.asList(files);

        Comparator<File> comparator = Comparator.comparingLong(File::lastModified);
        Comparator<File> reverseComparator = comparator.reversed();

        List<File> forwardOrder =;
        List<File> reverseOrder =;

        System.out.println("*** Unsorted ***");

        System.out.println("*** Sort ***");

        System.out.println("*** Reverse Sort ***");

    private static void processFile(File file) {
        try {
            if (file.isFile()) {
                System.out.println(file.getCanonicalPath() + " - " + new Date(file.lastModified()));
        } catch (Exception e) {

Emulate ggplot2 default color palette

This is the result from


Four color ggplot


Three color ggplot

"Cross origin requests are only supported for HTTP." error when loading a local file

It simply says that the application should be run on a web server. I had the same problem with chrome, I started tomcat and moved my application there, and it worked.

UICollectionView auto scroll to cell at IndexPath

New, Edited Answer:

Add this in viewDidLayoutSubviews


override func viewDidLayoutSubviews() {
    let indexPath = IndexPath(item: 12, section: 0)
    self.collectionView.scrollToItem(at: indexPath, at: [.centeredVertically, .centeredHorizontally], animated: true)

Normally, .centerVertically is the case


-(void)viewDidLayoutSubviews {
   [super viewDidLayoutSubviews];
    NSIndexPath *indexPath = [NSIndexPath indexPathForItem:12 inSection:0];
   [self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically | UICollectionViewScrollPositionCenteredHorizontally animated:NO];

Old answer working for older iOS

Add this in viewWillAppear:

[self.view layoutIfNeeded];
[self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically animated:NO];

How to print all session variables currently set?

You could use the following code.


Pan & Zoom Image

I also tried this answer but was not entirely happy with the result. I kept googling around and finally found a Nuget Package that helped me to manage the result I wanted, anno 2021. I would like to share it with the former developers of Stack Overflow.

I used this Nuget Package Gu.WPF.Geometry found via this Github Repository. All credits for develoment should go to Johan Larsson, the owner of this package.

How I used it? I wanted to have the commands as buttons below the zoombox, as shown here in MachineLayoutControl.xaml .

       <ResourceDictionary Source="Resources/ResourceDictionaries/AllResourceDictionariesCombined.xaml" />

   <Grid Margin="0">
           <RowDefinition Height="*" />
           <RowDefinition Height="Auto" />

           Style="{StaticResource Border_Head}"
               Visibility="{Binding Zoombox_Visibility}">
               <ContentControl Content="{Binding Viewing_Canvas}" />
                   CommandTarget="{Binding ElementName=ImageBox}"
                   Content="Zoom In"
                   Style="{StaticResource StyleForResizeButtons}" />

                   CommandTarget="{Binding ElementName=ImageBox}"
                   Content="Zoom Out"
                   Style="{StaticResource StyleForResizeButtons}" />

                   CommandTarget="{Binding ElementName=ImageBox}"
                   Content="See Full Machine"
                   Style="{StaticResource StyleForResizeButtons}" />

                   CommandTarget="{Binding ElementName=ImageBox}"
                   Content="Zoom To Machine Width"
                   Style="{StaticResource StyleForResizeButtons}" />


In the underlying Viewmodel, I had the following relevant code:

public Visibility Zoombox_Visibility { get => movZoombox_Visibility; set { movZoombox_Visibility = value; OnPropertyChanged(nameof(Zoombox_Visibility)); } }
public Canvas Viewing_Canvas { get => mdvViewing_Canvas; private set => mdvViewing_Canvas = value; }

Also, I wanted that immediately on loading, the Uniform to Fill Command was executed, this is something that I managed to do in the code-behind MachineLayoutControl.xaml.cs . You see that I only set the Zoombox to visible if the command is executed, to avoid "flickering" when the usercontrol is loading.

    public partial class MachineLayoutControl : UserControl
        #region Constructors

        public MachineLayoutControl()
            Loaded += MyWindow_Loaded;

        #endregion Constructors

        #region EventHandlers

        private void MyWindow_Loaded(object sender, RoutedEventArgs e)
               new Action(() =>
                   ZoomCommands.Uniform.Execute(null, ImageBox);
                   ((MachineLayoutControlViewModel)DataContext).Zoombox_Visibility = Visibility.Visible;

        #endregion EventHandlers


How can I delete derived data in Xcode 8?

The simplest and fastest way is the following (if you have not changed the defaults folder for DerivedData).

Open terminal and past the following:

rm -rf ~/Library/Developer/Xcode/DerivedData

VBA changing active workbook

Use ThisWorkbook which will refer to the original workbook which holds the code.

Alternatively at code start

Dim Wb As Workbook
Set Wb = ActiveWorkbook

sample code that activates all open books before returning to ThisWorkbook

Sub Test()
Dim Wb As Workbook
Dim Wb2 As Workbook
Set Wb = ThisWorkbook
For Each Wb2 In Application.Workbooks
End Sub

PowerShell script to return versions of .NET Framework on a machine?

Here's my take on this question following the msft documentation:

$gpParams = @{
    Path        = 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full'
    ErrorAction = 'SilentlyContinue'
$release = Get-ItemProperty @gpParams | Select-Object -ExpandProperty Release

".NET Framework$(
    switch ($release) {
        ({ $_ -ge 528040 }) { ' 4.8'; break }
        ({ $_ -ge 461808 }) { ' 4.7.2'; break }
        ({ $_ -ge 461308 }) { ' 4.7.1'; break }
        ({ $_ -ge 460798 }) { ' 4.7'; break }
        ({ $_ -ge 394802 }) { ' 4.6.2'; break }
        ({ $_ -ge 394254 }) { ' 4.6.1'; break }
        ({ $_ -ge 393295 }) { ' 4.6'; break }
        ({ $_ -ge 379893 }) { ' 4.5.2'; break }
        ({ $_ -ge 378675 }) { ' 4.5.1'; break }
        ({ $_ -ge 378389 }) { ' 4.5'; break }
        default { ': 4.5+ not installed.' }

This example works with all PowerShell versions and will work in perpetuity as 4.8 is the last .NET Framework version.

How to change progress bar's progress color in Android

simply use:

PorterDuff.Mode mode = PorterDuff.Mode.SRC_IN;
    mode = PorterDuff.Mode.MULTIPLY;

} else {
    Drawable progressDrawable;
    progressDrawable = (progressBar.isIndeterminate() ? progressBar.getIndeterminateDrawable() : progressBar.getProgressDrawable()).mutate();
    progressDrawable.setColorFilter(context.getResources().getColor(Color.RED), mode);

What is the { get; set; } syntax in C#?

A property is a like a layer that separates the private variable from other members of a class. From outside world it feels like a property is just a field, a property can be accessed using .Property

public class Person
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string FullName => $"{FirstName} {LastName}";

public class Person
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string FullName { get { return $"{FirstName} {LastName}"; } }

FullName is a Property. The one with arrow is a shortcut. From outside world, we can access FullName like this:

var person = new Person();

Callers do not care about how you implemented the FullName. But inside the class you can change FullName whatever you want.

Check out Microsoft Documentation for more detailed explanation:


Having run both queries on a SQL Server 2012 instance, I can confirm the first query was fastest in my case.

The query with the LIKE keyword showed a clustered index scan.

The CONTAINS also had a clustered index scan with additional operators for the full text match and a merge join.


Retrieve last 100 lines logs

I know this is very old, but, for whoever it may helps.

less +F my_log_file.log

that's just basic, with less you can do lot more powerful things. once you start seeing logs you can do search, go to line number, search for pattern, much more plus it is faster for large files.

its like vim for logs[totally my opinion]

original less's documentation :

less cheatsheet :

How to do a non-greedy match in grep?

Actualy the .*? only works in perl. I am not sure what the equivalent grep extended regexp syntax would be. Fortunately you can use perl syntax with grep so grep -P would work but grep -E which is same as egrep would not work (it would be greedy).

See also:

How to install both Python 2.x and Python 3.x in Windows

If you can't get anything else to work, open an interpreter in whichever version you choose (I prefer using iPython) and:

import subprocess'python -flags')

This uses whichever python version you are currently operating under. Works fine for a single script, but will quickly get out of hand if there are lots of scripts you run, in which case you can always make a batch file with all of these calls inside. Not the most elegant answer, but it works.

Is there a way to make aliases for different python version a la Linux?

#1214 - The used table type doesn't support FULLTEXT indexes

Before MySQL 5.6 Full-Text Search is supported only with MyISAM Engine.

Therefore either change the engine for your table to MyISAM

CREATE TABLE gamemech_chat (
  id bigint(20) unsigned NOT NULL auto_increment,
  from_userid varchar(50) NOT NULL default '0',
  to_userid varchar(50) NOT NULL default '0',
  text text NOT NULL,
  systemtext text NOT NULL,
  timestamp datetime NOT NULL default '0000-00-00 00:00:00',
  chatroom bigint(20) NOT NULL default '0',
  PRIMARY KEY  (id),
  KEY from_userid (from_userid),
  FULLTEXT KEY from_userid_2 (from_userid),
  KEY chatroom (chatroom),
  KEY timestamp (timestamp)

Here is SQLFiddle demo

or upgrade to 5.6 and use InnoDB Full-Text Search.

How to use LogonUser properly to impersonate domain user from workgroup client

this works for me, full working example (I wish more people would do this):

//logon impersonation
using System.Runtime.InteropServices; // DllImport
using System.Security.Principal; // WindowsImpersonationContext
using System.Security.Permissions; // PermissionSetAttribute


class Program {

    // obtains user token
    [DllImport("advapi32.dll", SetLastError = true)]
    public static extern bool LogonUser(string pszUsername, string pszDomain, string pszPassword,
        int dwLogonType, int dwLogonProvider, ref IntPtr phToken);

    // closes open handes returned by LogonUser
    [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
    public extern static bool CloseHandle(IntPtr handle);

    public void DoWorkUnderImpersonation() {
        //elevate privileges before doing file copy to handle domain security
        WindowsImpersonationContext impersonationContext = null;
        IntPtr userHandle = IntPtr.Zero;
        const int LOGON32_PROVIDER_DEFAULT = 0;
        const int LOGON32_LOGON_INTERACTIVE = 2;
        string domain = ConfigurationManager.AppSettings["ImpersonationDomain"];
        string user = ConfigurationManager.AppSettings["ImpersonationUser"];
        string password = ConfigurationManager.AppSettings["ImpersonationPassword"];

        try {
            Console.WriteLine("windows identify before impersonation: " + WindowsIdentity.GetCurrent().Name);

            // if domain name was blank, assume local machine
            if (domain == "")
                domain = System.Environment.MachineName;

            // Call LogonUser to get a token for the user
            bool loggedOn = LogonUser(user,
                                        ref userHandle);

            if (!loggedOn) {
                Console.WriteLine("Exception impersonating user, error code: " + Marshal.GetLastWin32Error());

            // Begin impersonating the user
            impersonationContext = WindowsIdentity.Impersonate(userHandle);

            Console.WriteLine("Main() windows identify after impersonation: " + WindowsIdentity.GetCurrent().Name);

            //run the program with elevated privileges (like file copying from a domain server)

        } catch (Exception ex) {
            Console.WriteLine("Exception impersonating user: " + ex.Message);
        } finally {
            // Clean up
            if (impersonationContext != null) {

            if (userHandle != IntPtr.Zero) {

    private void DoWork() {
        //everything in here has elevated privileges

        //example access files on a network share through e$ 
        string[] files = System.IO.Directory.GetFiles(@"\\domainserver\e$\images", "*.jpg");

What's the use of "enum" in Java?

1) enum is a keyword in Object oriented method.

2) It is used to write the code in a Single line, That's it not more than that.

     public class NAME
        public static final String THUNNE = "";
        public static final String SHAATA = ""; 
        public static final String THULLU = ""; 

-------This can be replaced by--------


3) Most of the developers do not use enum keyword, it is just a alternative method..

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

Re/installing .NET framework did not worked for me. Some less professional soft wares like tuneup utilities manipulate or constantly keep in use .NET framework files. like that .dll . I learned it while i was trying to uninstall .NET updates before re-installation.

  • Dont forget to uninstall wamp from control panel before reinstalling it.
  • Uninstalling .NET updates of windows. (controlPanel->uninstall a
  • program->view updates) Uninstalling soft wares that prevents
  • uninstalling .NETs . Finished successfully uninstalling .NET
  • framework updates. Check windows updates. Install updates that shows up AFTER check (.NET framework update. 3update for me under win7x64)
  • install wamp (finished flawlessly for me)

new DateTime() vs default(DateTime)

The simpliest way to understand it is that DateTime is a struct. When you initialize a struct it's initialize to it's minimum value : DateTime.Min

Therefore there is no difference between default(DateTime) and new DateTime() and DateTime.Min

Cannot open include file: 'stdio.h' - Visual Studio Community 2017 - C++ Error


Right Click on your project.

Go to Properties->CUDA and set "CUDA Toolkit Custom Dir" to your CUDA toolkit directory.

For me it was: C:\\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.0

enter image description here

How to search for an element in an stl list?

Besides using std::find (from algorithm), you can also use std::find_if (which is, IMO, better than std::find), or other find algorithm from this list

#include <list>
#include <algorithm>
#include <iostream>

int main()
    std::list<int> myList{ 5, 19, 34, 3, 33 };

    auto it = std::find_if( std::begin( myList ),
                            std::end( myList ),
                            [&]( const int v ){ return 0 == ( v % 17 ); } );
    if ( myList.end() == it )
        std::cout << "item not found" << std::endl;
        const int pos = std::distance( myList.begin(), it ) + 1;
        std::cout << "item divisible by 17 found at position " << pos << std::endl;

npm not working - "read ECONNRESET"

npm config rm proxy

npm config rm https-proxy

works for me!

Reset IntelliJ UI to Default

All above answers are correct, but you loose configuration settings.

But if your IDE's only themes or fonts are changed or some UI related issues and you want to restore to default theme, then just delete


file while IDE is not running, then after next restart IDE's theme will gets reset to default.

When should you use a class vs a struct in C++?

Structs by default have public access and classes by default have private access.

Personally I use structs for Data Transfer Objects or as Value Objects. When used as such I declare all members as const to prevent modification by other code.

How can I parse a YAML file from a Linux shell script?

Whenever you need a solution for "How to work with YAML/JSON/compatible data from a shell script" which works on just about every OS with Python (*nix, OSX, Windows), consider yamlpath, which provides several command-line tools for reading, writing, searching, and merging YAML, EYAML, JSON, and compatible files. Since just about every OS either comes with Python pre-installed or it is trivial to install, this makes yamlpath highly portable. Even more interesting: this project defines an intuitive path language with very powerful, command-line-friendly syntax that enables accessing one or more nodes.

To your specific question and after installing yamlpath using Python's native package manager or your OS's package manager (yamlpath is available via RPM to some OSes):

# Read values directly from YAML (or EYAML, JSON, etc) for use in this shell script:
myShellVar=$(yaml-get[matter%how].complex source-file.yaml)

# Use the value any way you need:
echo "Retrieved ${myShellVar}"

# Perhaps change the value and write it back:
myShellVar="New Value"
yaml-set --change=/any/path/no[matter%how]/complex --value="$myShellVar" source-file.yaml

You didn't specify that the data was a simple Scalar value though, so let's up the ante. What if the result you want is an Array? Even more challenging, what if it's an Array-of-Hashes and you only want one property of each result? Suppose further that your data is actually spread out across multiple YAML files and you need all the results in a single query. That's a much more interesting question to demonstrate with. So, suppose you have these two YAML files:

File: data1.yaml

  - name: Doohickey
    sku: 0-000-1
    price: 4.75
    weight: 2.7g
  - name: Doodad
    sku: 0-000-2
    price: 10.5
    weight: 5g
  - name: Oddball
    sku: 0-000-3
    price: 25.99
    weight: 25kg

File: data2.yaml

  - name: Fob
    sku: 0-000-4
    price: 0.99
    weight: 18mg
  - name: Doohickey
    price: 10.5
  - name: Oddball
    sku: 0-000-3
    description: This ball is odd

How would you report only the sku of every item in inventory after applying the changes from data2.yaml to data1.yaml, all from a shell script? Try this:

baubleSKUs=($(yaml-merge --aoh=deep data1.yaml data2.yaml | yaml-get --query=/baubles/sku -))

for sku in "${baubleSKUs[@]}"; do
    echo "Found bauble SKU:  ${sku}"

You get exactly what you need from only a few lines of code:

Found bauble SKU:  0-000-1
Found bauble SKU:  0-000-2
Found bauble SKU:  0-000-3
Found bauble SKU:  0-000-4

As you can see, yamlpath turns very complex problems into trivial solutions. Note that the entire query was handled as a stream; no YAML files were changed by the query and there were no temp files.

I realize this is "yet another tool to solve the same question" but after reading the other answers here, yamlpath appears more portable and robust than most alternatives. It also fully understands YAML/JSON/compatible files and it does not need to convert YAML to JSON to perform requested operations. As such, comments within the original YAML file are preserved whenever you need to change data in the source YAML file. Like some alternatives, yamlpath is also portable across OSes. More importantly, yamlpath defines a query language that is extremely powerful, enabling very specialized/filtered data queries. It can even operate against results from disparate parts of the file in a single query.

If you want to get or set many values in the data at once -- including complex data like hashes/arrays/maps/lists -- yamlpath can do that. Want a value but don't know precisely where it is in the document? yamlpath can find it and give you the exact path(s). Need to merge multiple data file together, including from STDIN? yamlpath does that, too. Further, yamlpath fully comprehends YAML anchors and their aliases, always giving or changing exactly the data you expect whether it is a concrete or referenced value.

Disclaimer: I wrote and maintain yamlpath, which is based on ruamel.yaml, which is in turn based on PyYAML. As such, yamlpath is fully standards-compliant.

Turning off eslint rule for a specific file

To disable a specific rule for the file:

/* eslint-disable no-use-before-define */

Note there is a bug in eslint where single line comment will not work -

// eslint-disable max-classes-per-file
// This fails!

Check this post

Bootstrap Navbar toggle button not working

Wasted several hours only to realize that viewport meta was missing from my code. Adding here just in case some one else misses it out.

As soon as I added this, the toggle started working fine.

<meta name="viewport" content="width=device-width, initial-scale=1">

Empty an array in Java / processing

array = new String[array.length];

WooCommerce return product object by id

Alright, I deserve to be throttled. definitely an RTM but not for WooCommerce, for Wordpress. Solution found due to a JOLT cola (all hail JOLT cola).

TASK: Field named 'related_product_ids' added to a custom post type. So when that post is displayed mini product displays can be displayed with it.

PROBLEM: Was having a problem getting the multiple ids returned via WP_Query.


$related_id_list          = get_post_custom_values('related_product_ids');
    // Get comma delimited list from current post
$related_product_ids      = explode(",", trim($related_id_list[0],','));
    // Return an array of the IDs ensure no empty array elements from extra commas
$related_product_post_ids = array( 'post_type' => 'product', 
                                   'post__in'  => $related_product_ids,
                                   'meta_query'=> array( 
                                        array( 'key'    => '_visibility',
                                               'value'  => array('catalog', 'visible'),'compare' => 'IN'
    // Query to get all product posts matching given IDs provided it is a published post
$loop = new WP_Query( $related_posts );
    // Execute query
while ( $loop->have_posts() ) : $loop->the_post(); $_product = get_product( $loop->post->ID );
    // Do stuff here to display your products 

Thank you for anyone who may have spent some time on this.


versionCode vs versionName in Android Manifest

Dont need to reverse your steps. As you increased your VersionCode, it means your application has upgraded already. The VersionName is just a string which is presented to user for user readability. Google play does not take any action depending on VersionName.

Stop a gif animation onload, on mouseover start the activation

I think the jQuery plugin freezeframe.js might come in handy for you. freezeframe.js is a jQuery Plugin To Automatically Pause GIFs And Restart Animating On Mouse Hover.

I guess you can easily adapt it to make it work on page load instead.

How do I use a char as the case in a switch-case?

Here's an example:

public class Main {

    public static void main(String[] args) {

        double val1 = 100;
        double val2 = 10;
        char operation = 'd';
        double result = 0;

        switch (operation) {

            case 'a':
                result = val1 + val2; break;

            case 's':
                result = val1 - val2; break;
            case 'd':
                if (val2 != 0)
                    result = val1 / val2; break;
            case 'm':
                result = val1 * val2; break;

            default: System.out.println("Not a defined operation");



laravel foreach loop in controller

Hi, this will throw an error:

foreach ($product->sku as $sku){ 
// Code Here

because you cannot loop a model with a specific column ($product->sku) from the table.
So you must loop on the whole model:

foreach ($product as $p) {
// code

Inside the loop you can retrieve whatever column you want just adding "->[column_name]"

foreach ($product as $p) {
echo $p->sku;

Have a great day

How to change date format (MM/DD/YY) to (YYYY-MM-DD) in date picker

This work for me:

          singleDatePicker: true,
          locale: {
           format: 'DD/MM/YYYY'
         calender_style: "picker_4", }, 
function(start, end, label) {
          console.log(start.toISOString(), end.toISOString(), label); 

Send password when using scp to copy files from one server to another

Here is how I resolved it.

It is not the most secure way however it solved my problem as security was not an issue on internal servers.

Create a new file say password.txt and store the password for the server where the file will be pasted. Save this to a location on the host server.

scp -W location/password.txt copy_file_location paste_file_location


How to subtract one month using moment.js?

For substracting in moment.js:

moment().subtract(1, 'months').format('MMM YYYY');


Before version 2.8.0, the moment#subtract(String, Number) syntax was also supported. It has been deprecated in favor of moment#subtract(Number, String).

  moment().subtract('seconds', 1); // Deprecated in 2.8.0
  moment().subtract(1, 'seconds');

As of 2.12.0 when decimal values are passed for days and months, they are rounded to the nearest integer. Weeks, quarters, and years are converted to days or months, and then rounded to the nearest integer.

  moment().subtract(1.5, 'months') == moment().subtract(2, 'months')
  moment().subtract(.7, 'years') == moment().subtract(8, 'months') //.7*12 = 8.4, rounded to 8

Format a JavaScript string using placeholders and an object of substitutions?

Currently there is still no native solution in Javascript for this behavior. Tagged templates are something related, but don't solve it.

Here there is a refactor of alex's solution with an object for replacements.

The solution uses arrow functions and a similar syntax for the placeholders as the native Javascript interpolation in template literals ({} instead of %%). Also there is no need to include delimiters (%) in the names of the replacements.

There are two flavors (three with the update): descriptive, reduced, elegant reduced with groups.

Descriptive solution:

const stringWithPlaceholders = 'My Name is {name} and my age is {age}.';

const replacements = {
  name: 'Mike',
  age: '26',

const string = stringWithPlaceholders.replace(
  placeholderWithDelimiters => {
    const placeholderWithoutDelimiters = placeholderWithDelimiters.substring(
      placeholderWithDelimiters.length - 1,
    const stringReplacement = replacements[placeholderWithoutDelimiters] || placeholderWithDelimiters;
    return stringReplacement;


Reduced solution:

const stringWithPlaceholders = 'My Name is {name} and my age is {age}.';

const replacements = {
  name: 'Mike',
  age: '26',

const string = stringWithPlaceholders.replace(/{\w+}/g, placeholder =>
  replacements[placeholder.substring(1, placeholder.length - 1)] || placeholder


UPDATE 2020-12-10

Elegant reduced solution with groups, as suggested by @Kade in the comments:

const stringWithPlaceholders = 'My Name is {name} and my age is {age}.';

const replacements = {
  name: 'Mike',
  age: '26',

const string = stringWithPlaceholders.replace(
  (placeholderWithDelimiters, placeholderWithoutDelimiters) =>
    replacements[placeholderWithoutDelimiters] || placeholderWithDelimiters


UPDATE 2021-01-21

Support empty string as a replacement, as suggested by @Jesper in the comments:

const stringWithPlaceholders = 'My Name is {name} and my age is {age}.';

const replacements = {
  name: 'Mike',
  age: '',

const string = stringWithPlaceholders.replace(
  (placeholderWithDelimiters, placeholderWithoutDelimiters) =>
  replacements.hasOwnProperty(placeholderWithoutDelimiters) ? 
    replacements[placeholderWithoutDelimiters] : placeholderWithDelimiters


Learning Ruby on Rails

My company has been developing, a knowledge management and decision support platform for three years. Over the past few years we've learned a lot about rails and here are some of my recommendations.

  1. Switch to Mac! The tools that are available to you and the development environment on Mac allows you to be far more productive than on Windows.

  2. has a wealth of informative screencasts from beginner to expert. You can always find new and more efficient ways of doing things from Ryan's posts.

  3. Scaling Rails screencasts coupled with NewRelic has provided powerful insight into the performance of our application and allows us to develop effectively while keeping our eyes open for future scalability issues.

What is the difference between using constructor vs getInitialState in React / React Native?

Constructor The constructor is a method that's automatically called during the creation of an object from a class. ... Simply put, the constructor aids in constructing things. In React, the constructor is no different. It can be used to bind event handlers to the component and/or initializing the local state of the component.Jan 23, 2019

getInitialState In ES6 classes, you can define the initial state by assigning this.state in the constructor:

Look at this example

var Counter = createReactClass({
  getInitialState: function() {
    return {count: this.props.initialCount};
  // ...

With createReactClass(), you have to provide a separate getInitialState method that returns the initial state:

How to get the last character of a string in a shell?

I know this is a very old thread, but no one mentioned which to me is the cleanest answer:

echo -n $str | tail -c 1

Note the -n is just so the echo doesn't include a newline at the end.

How do I shut down a python simpleHTTPserver?

It seems like overkill but you can use supervisor to start and stop your simpleHttpserver, and completely manage it as a service.

Or just run it in the foreground as suggested and kill it with control c

Download history stock prices automatically from yahoo finance in python

Extending @Def_Os's answer with an actual demo...

As @Def_Os has already said - using Pandas Datareader makes this task a real fun

In [12]: from pandas_datareader import data

pulling all available historical data for AAPL starting from 1980-01-01

#In [13]: aapl = data.DataReader('AAPL', 'yahoo', '1980-01-01')

# yahoo api is inconsistent for getting historical data, please use google instead.
In [13]: aapl = data.DataReader('AAPL', 'google', '1980-01-01')

first 5 rows

In [14]: aapl.head()
                 Open       High     Low   Close     Volume  Adj Close
1980-12-12  28.750000  28.875000  28.750  28.750  117258400   0.431358
1980-12-15  27.375001  27.375001  27.250  27.250   43971200   0.408852
1980-12-16  25.375000  25.375000  25.250  25.250   26432000   0.378845
1980-12-17  25.875000  25.999999  25.875  25.875   21610400   0.388222
1980-12-18  26.625000  26.750000  26.625  26.625   18362400   0.399475

last 5 rows

In [15]: aapl.tail()
                 Open       High        Low      Close    Volume  Adj Close
2016-06-07  99.250000  99.870003  98.959999  99.029999  22366400  99.029999
2016-06-08  99.019997  99.559998  98.680000  98.940002  20812700  98.940002
2016-06-09  98.500000  99.989998  98.459999  99.650002  26419600  99.650002
2016-06-10  98.529999  99.349998  98.480003  98.830002  31462100  98.830002
2016-06-13  98.690002  99.120003  97.099998  97.339996  37612900  97.339996

save all data as CSV file

In [16]: aapl.to_csv('d:/temp/aapl_data.csv')

d:/temp/aapl_data.csv - 5 first rows

Date,Open,High,Low,Close,Volume,Adj Close

qmake: could not find a Qt installation of ''

I have qt4 installed. I found that using the following path worked for me, despite 'which qmake' returning /usr/bin/qmake, which is just a link to qtchooser anyway.

The following path works for me, on a 64 bit system. Running from the full path of:


ASP.NET set hiddenfield a value in Javascript


The id you set in server is the server id which is different from client id.

Get enum values as List of String in Java 8

You could also do something as follow

public enum DAY {MON, TUES, WED, THU, FRI, SAT, SUN};
EnumSet.allOf(DAY.class).stream().map(e ->



The main reason why I stumbled across this question is that I wanted to write a generic validator that validates whether a given string enum name is valid for a given enum type (Sharing in case anyone finds useful).

For the validation, I had to use Apache's EnumUtils library since the type of enum is not known at compile time.

@SuppressWarnings({ "unchecked", "rawtypes" })
public static void isValidEnumsValid(Class clazz, Set<String> enumNames) {
    Set<String> notAllowedNames =
            .filter(enumName -> !EnumUtils.isValidEnum(clazz, enumName))

    if (notAllowedNames.size() > 0) {
        String validEnumNames = (String) EnumUtils.getEnumMap(clazz).keySet().stream()
            .collect(Collectors.joining(", "));

        throw new IllegalArgumentException("The requested values '" +
                .collect(Collectors.joining(",")) + "' are not valid. Please select one more (case-sensitive) "
                + "of the following : " + validEnumNames);

I was too lazy to write an enum annotation validator as shown in here

How do I output an ISO 8601 formatted string in JavaScript?

The question asked was ISO format with reduced precision. Voila:

 new Date().toISOString().slice(0, 19) + 'Z'
 // '2014-10-23T13:18:06Z'

Assuming the trailing Z is wanted, otherwise just omit.

{"<user xmlns=''> was not expected.} Deserializing Twitter XML

Even easier is just to add the following annotations to the top of your class:

[Serializable, XmlRoot("user")]
public partial class User

SEVERE: ContainerBase.addChild: start:org.apache.catalina.LifecycleException: Failed to start error

I had the same error statement following a "Failed to access resource" error message:


#cat callflow-java-logger-1.log.0


Dec 09, 2015 8:09:03 AM org.apache.catalina.loader.WebappLoader startInternal
SEVERE: LifecycleException Failed to access resource /WEB-INF/lib/ojdbc14.jar

In my case the solution was changing the connector permissions

-rw------- 1 owner creator size date ojdbc14.jar

This file in question wasn't initially located at /WEB-INF/lib, which was probably due to how BIRT works. It can be tricky if you are dealing with a higher number of files.

I need a Nodejs scheduler that allows for tasks at different intervals

I think the best ranking is




and the sample of node-schedule is below:

var schedule = require("node-schedule");
var rule = new schedule.RecurrenceRule();
//rule.minute = 40;
rule.second = 10;
var jj = schedule.scheduleJob(rule, function(){
    console.log("execute jj");

Maybe you can find the answer from node modules.

How do I remove all non alphanumeric characters from a string except dash?

Here's an extension method using @ata answer as inspiration.

"hello-world123, 456".MakeAlphaNumeric(new char[]{'-'});// yields "hello-world123456"

or if you require additional characters other than hyphen...

"hello-world123, 456!?".MakeAlphaNumeric(new char[]{'-','!'});// yields "hello-world123456!"

public static class StringExtensions
    public static string MakeAlphaNumeric(this string input, params char[] exceptions)
        var charArray = input.ToCharArray();
        var alphaNumeric = Array.FindAll<char>(charArray, (c => char.IsLetterOrDigit(c)|| exceptions?.Contains(c) == true));
        return new string(alphaNumeric);

Get current category ID of the active page

You can try using get_the_category():

$categories = get_the_category();
$category_id = $categories[0]->cat_ID;

Can you have if-then-else logic in SQL?

With SQL server you can just use a CTE instead of IF/THEN logic to make it easy to map from your existing queries and change the number of involved queries;

WITH cte AS (
    SELECT product,price,1 a FROM table1 WHERE project=1   UNION ALL
    SELECT product,price,2 a FROM table1 WHERE customer=2  UNION ALL
    SELECT product,price,3 a FROM table1 WHERE company=3
SELECT TOP 1 WITH TIES product,price FROM cte ORDER BY a;

An SQLfiddle to test with.

Alternately, you can combine it all into one SELECT to simplify it for the optimizer;

SELECT TOP 1 WITH TIES product,price FROM table1 
WHERE project=1 OR customer=2 OR company=3
              WHEN customer=2 THEN 2
              WHEN company=3  THEN 3 END;

Another SQLfiddle.

How to run multiple SQL commands in a single SQL connection?

Here you can find Postgre example, this code run multiple sql commands (update 2 columns) within single SQL connection

public static class SQLTest
        public static void NpgsqlCommand()
            using (NpgsqlConnection connection = new NpgsqlConnection("Server = ; Port = ; User Id = ; " + "Password = ; Database = ;"))
                NpgsqlCommand command1 = new NpgsqlCommand("update xy set xw = 'a' WHERE aa='bb'", connection);
                NpgsqlCommand command2 = new NpgsqlCommand("update xy set xw = 'b' where bb = 'cc'", connection);

How to escape indicator characters (i.e. : or - ) in YAML

If you're using @ConfigurationProperties with Spring Boot 2 to inject maps with keys that contain colons then you need an additional level of escaping using square brackets inside the quotes because spring only allows alphanumeric and '-' characters, stripping out the rest. Your new key would look like this:

"[]": GoogleMapsKeyforThisDomain

See this github issue for reference.

How to colorize diff on the command line?

And for those occasions when a yum install colordiff or an apt-get install colordiff is not an option due to some insane constraint beyond your immediate control, or you're just feeling crazy, you can re-invent the wheel with a line of sed:

sed 's/^-/\x1b[41m-/;s/^+/\x1b[42m+/;s/^@/\x1b[34m@/;s/$/\x1b[0m/'

Throw that in a shell script and pipe unified diff output through it.

It makes hunk markers blue and highlights new/old filenames and added/removed lines in green and red background, respectively.1 And it will make trailing space2 changes more readily apparent than colordiff can.

1 Incidentally, the reason for highlighting the filenames the same as the modified lines is that to correctly differentiate between the filenames and the modified lines requires properly parsing the diff format, which is not something to tackle with a regex. Highlighting them the same works "well enough" visually and makes the problem trivial. That said, there are some interesting subtleties.

2 But not trailing tabs. Apparently tabs don't get their background set, at least in my xterm. It does make tab vs space changes stand out a bit though.

Yum fails with - There are no enabled repos.

ok, so my problem was that I tried to install the package with yum which is the primary tool for getting, installing, deleting, querying, and managing Red Hat Enterprise Linux RPM software packages from official Red Hat software repositories, as well as other third-party repositories.

But I'm using ubuntu and The usual way to install packages on the command line in Ubuntu is with apt-get. so the right command was:

sudo apt-get install libstdc++.i686

Xcode build failure "Undefined symbols for architecture x86_64"

I have found this can also occur if you drag a folder with Objective-C files into your project. If that folder appears blue I think it indicates its not properly linked. You can verify this (if you use version control) because whenever you add new files the pbxproj file should update with links to those new files. However you may find that after you added a folder that the pbxproj file did not change (and hence there is a linking error). So you will get auto-complete working and it will find the classes you imported, but when it goes to actually build the image it fails with this error code.

The solution is to not add the folder but rather add the files. Do this and you should see the pbxproj file update and it should fix this error.

This also assumes you've done what was suggested above and have properly linked all the right frameworks.

git pull fails "unable to resolve reference" "unable to update local ref"

To Answer this in very short, this issue comes when your local has some information about the remote and someone changes something which makes remote and your changes unsync.

I was getting this issue because someone has deleted remote branch and again created with the same name.

For dealing with such issues, do a pull or fetch from remote.

git remote prune origin

or if you are using any GUI, do a fetch from remote.

enter image description here

SQL Server datetime LIKE select?

Try this

SELECT top 10 * from record WHERE  IsActive = 1 and CONVERT(VARCHAR, register_date, 120) LIKE '2020-01%'

How to convert a private key to an RSA private key?

This may be of some help (do not literally write out the backslashes '\' in the commands, they are meant to indicate that "everything has to be on one line"):

Which Command to Apply When

It seems that all the commands (in grey) take any type of key file (in green) as "in" argument. Which is nice.

Here are the commands again for easier copy-pasting:

openssl rsa                                                -in $FF -out $TF
openssl rsa -aes256                                        -in $FF -out $TF
openssl pkcs8 -topk8 -nocrypt                              -in $FF -out $TF
openssl pkcs8 -topk8 -v2 aes-256-cbc -v2prf hmacWithSHA256 -in $FF -out $TF


openssl rsa -check -in $FF
openssl rsa -text  -in $FF

Does a VPN Hide my Location on Android?

Your question can be conveniently divided into several parts:

Does a VPN hide location? Yes, he is capable of this. This is not about GPS determining your location. If you try to change the region via VPN in an application that requires GPS access, nothing will work. However, sites define your region differently. They get an IP address and see what country or region it belongs to. If you can change your IP address, you can change your region. This is exactly what VPNs can do.

How to hide location on Android? There is nothing difficult in figuring out how to set up a VPN on Android, but a couple of nuances still need to be highlighted. Let's start with the fact that not all Android VPNs are created equal. For example, VeePN outperforms many other services in terms of efficiency in circumventing restrictions. It has 2500+ VPN servers and a powerful IP and DNS leak protection system.

You can easily change the location of your Android device by using a VPN. Follow these steps for any device model (Samsung, Sony, Huawei, etc.):

  1. Download and install a trusted VPN.

  2. Install the VPN on your Android device.

  3. Open the application and connect to a server in a different country.

  4. Your Android location will now be successfully changed!

Is it legal? Yes, changing your location on Android is legal. Likewise, you can change VPN settings in Microsoft Edge on your PC, and all this is within the law. VPN allows you to change your IP address, safeguarding your privacy and protecting your actual location from being exposed. However, VPN laws may vary from country to country. There are restrictions in some regions.

Brief summary: Yes, you can change your region on Android and a VPN is a necessary assistant for this. It's simple, safe and legal. Today, VPN is the best way to change the region and unblock sites with regional restrictions.

Plotting 4 curves in a single plot, with 3 y-axes

I know of plotyy that allows you to have two y-axes, but no "plotyyy"!

Perhaps you can normalize the y values to have the same scale (min/max normalization, zscore standardization, etc..), then you can just easily plot them using normal plot, hold sequence.

Here's an example:

%# random data
y = [randn(20,1)*1 + 0 , randn(20,1)*5 + 10 , randn(20,1)*0.3 + 50];

%# plotyy
plotyy(x,y(:,1), x,y(:,3))

%# orginial
subplot(221), plot(x,y(:,1), x,y(:,2), x,y(:,3))
title('original'), legend({'y1' 'y2' 'y3'})

%# normalize: (y-min)/(max-min) ==> [0,1]
yy = bsxfun(@times, bsxfun(@minus,y,min(y)), 1./range(y));
subplot(222), plot(x,yy(:,1), x,yy(:,2), x,yy(:,3))

%# standarize: (y - mean) / std ==> N(0,1)
yy = zscore(y);
subplot(223), plot(x,yy(:,1), x,yy(:,2), x,yy(:,3))

%# softmax normalization with logistic sigmoid ==> [0,1]
yy = 1 ./ ( 1 + exp( -zscore(y) ) );
subplot(224), plot(x,yy(:,1), x,yy(:,2), x,yy(:,3))

plotyy normalization

How to simplify a null-safe compareTo() implementation?

You could design your class to be immutable (Effective Java 2nd Ed. has a great section on this, Item 15: Minimize mutability) and make sure upon construction that no nulls are possible (and use the null object pattern if needed). Then you can skip all those checks and safely assume the values are not null.

Getting an Embedded YouTube Video to Auto Play and Loop

All of the answers didn't work for me, I checked the playlist URL and seen that playlist parameter changed to list! So it should be:


So here is the full code I use make a clean, looping, autoplay video:

<iframe width="100%" height="425" src="" frameborder="0" allowfullscreen></iframe>

How does BitLocker affect performance?

My current work machine came with bitlocker, and being an upgrade from the prior model. It only seemed faster to me. What I have found, however, is that bitlocker is more bullet proof than truecrypt, when it comes to accurately laying down the data. I do a lot of work in SAS which constantly writes backup copies to disk as it moves along and shoots a variety of output types to disk at the end. SAS works fine writing output from multithreaded processes back to bitlocker and doesn't seem to know it's there. This has not been the case for me with truecrypt. I'm not sure what happens or how, but I found that processes got out of synch when working with source/output data in a truecrypt container, which is what I installed on my second work computer since it had no bitlocker. The constant backups were shooting to an SSD while the truecrypt results were on a regular HD. Maybe that speed difference helped trip it up. Whatever the cause, I had to quit using truecrypt on that second computer because it made my SAS results out of synch with respect to processing order and it screwed up some of my processes and data. Scary stuff in my world.

I work with people who have successfully used Truecrypt on the exact same computer, but they weren't using a disk intensive app. like SAS.

Bitlocker to Go, the encryption which bitlocker applies to thumb-drives, does slow things down quite a bit when it comes to read/write times. It's not too hard to use as long as you remember your password on the thumbdrive, and are willing to wait for it to format/initialize the drive, but in my experience it made access to the flash drive about 4 times as slow. Don't know why it would slow down a thumb drive and not a disk but that's how it was for me and my coworker.

Based on my success with bitlocker at work, I bought Windows Pro for my home computer to get bitlocker and plan to encrypt some directories with it for things like financials.

regular expression to validate datetime format (MM/DD/YYYY)

In this case, to validate Date (DD-MM-YYYY) or (DD/MM/YYYY), with a year between 1900 and 2099,like this with month and Days validation

if (!Regex.Match(txtDob.Text, @"^(0[1-9]|1[0-9]|2[0-9]|3[0,1])([/+-])(0[1-9]|1[0-2])([/+-])(19|20)[0-9]{2}$").Success)                  
   MessageBox.Show("InValid Date of Birth");

How to add MVC5 to Visual Studio 2013?

With respect to other answers, it's not always there. Sometimes on setup process people forget to select the Web Developer Tools.

In order to fix that, one should:

  1. Open Programs and Features find Visual Studios related version there, click on it,
  2. Click to Change. Then the setup window will appear,
  3. Select Web Developer Tools there and continue to setup.

It will download or use the setup media if exist. After the setup windows may restart, and you are ready to have fun with your Web Developer Tools now.

How to find the type of an object in Go?

You can check the type of any variable/instance at runtime either using the "reflect" packages TypeOf function or by using fmt.Printf():

package main

import (

func main() {
    value1 := "Have a Good Day"
    value2 := 50
    value3 := 50.78

    fmt.Println(reflect.TypeOf(value1 ))

Java Replace Character At Specific Position Of String?

To replace a character at a specified position :

public static String replaceCharAt(String s, int pos, char c) {
   return s.substring(0,pos) + c + s.substring(pos+1);

jQuery function after .append

Well I've got exactly the same problem with size recalculation and after hours of headache I have to disagree with .append() behaving strictly synchronous. Well at least in Google Chrome. See following code.

var input = $( '<input />' );
input.append( arbitraryElement );
input.css( 'padding-left' );

The padding-left property is correctly retrieved in Firefox but it is empty in Chrome. Like all other CSS properties I suppose. After some experiments I had to settle for wrapping the CSS 'getter' into setTimeout() with 10 ms delay which I know is UGLY as hell but the only one working in Chrome. If any of you had an idea how to solve this issue better way I'd be very grateful.

How can I check if a URL exists via PHP?

to check if url is online or offline ---

function get_http_response_code($theURL) {
    $headers = @get_headers($theURL);
    return substr($headers[0], 9, 3);

Facebook Open Graph not clearing cache

I had a different, but similar problem with Facebook recently, and found that the scraper/debug page mentioned, simply does not appear to read any page in its entirety. My meta properties for Open Graph were further down in the head section, and the scraper would constantly inform me that the image specification was not correct, and would use a cached version regardless. I moved the Open Graph tags further up in the code, near the very top of the page, and then everything worked perfectly, every time.

jQuery to retrieve and set selected option value of html select element

Try this


How do you count the lines of code in a Visual Studio solution?

You can use free tool SourceMonitor

Gives a lot of measures: Lines of Code, Statement Count, Complexity, Block Depth

Has graphical outputs via charts

How to compare strings in sql ignoring case?

If you are matching the full value of the field use

WHERE UPPER(fieldName) = 'ANGEL'

EDIT: From your comment you want to use:

    RPAD(, 10,'=') "Nombre del Cliente"
    , RPAD(, 12,'*') "Nombre del Consumidor" 
    s_customer a, 
    s_region b 
    a.region_id = 

Using HTML5/JavaScript to generate and save a file

You can generate a data URI. However, there are browser-specific limitations.

Sorting a list using Lambda/Linq to objects

This can be done as

list.Sort( (emp1,emp2)=>emp1.FirstName.CompareTo(emp2.FirstName) );

The .NET framework is casting the lambda (emp1,emp2)=>int as a Comparer<Employee>.

This has the advantage of being strongly typed.

How to run a .jar in mac?

You don't need JDK to run Java based programs. JDK is for development which stands for Java Development Kit.

You need JRE which should be there in Mac.

Try: java -jar Myjar_file.jar

EDIT: According to this article, for Mac OS 10

The Java runtime is no longer installed automatically as part of the OS installation.

Then, you need to install JRE to your machine.

How to make graphics with transparent background in R using ggplot2?

Updated with the theme() function, ggsave() and the code for the legend background:

df <- data.frame(y = d, x = 1, group = rep(c("gr1", "gr2"), 50))
p <- ggplot(df) +
  stat_boxplot(aes(x = x, y = y, color = group), 
               fill = "transparent" # for the inside of the boxplot

Fastest way is using using rect, as all the rectangle elements inherit from rect:

p <- p +
        rect = element_rect(fill = "transparent") # all rectangles

More controlled way is to use options of theme:

p <- p +
    panel.background = element_rect(fill = "transparent"), # bg of the panel
    plot.background = element_rect(fill = "transparent", color = NA), # bg of the plot
    panel.grid.major = element_blank(), # get rid of major grid
    panel.grid.minor = element_blank(), # get rid of minor grid
    legend.background = element_rect(fill = "transparent"), # get rid of legend bg = element_rect(fill = "transparent") # get rid of legend panel bg

To save (this last step is important):

ggsave(p, filename = "tr_tst2.png",  bg = "transparent")

Reading string by char till end of line C/C++

The answer to your original question

How to read a string one char at the time, and stop when you reach end of line?

is, in C++, very simply, namely: use getline. The link shows a simple example:

#include <iostream>
#include <string>
int main () {
  std::string name;
  std::cout << "Please, enter your full name: ";
  std::getline (std::cin,name);
  std::cout << "Hello, " << name << "!\n";
  return 0;

Do you really want to do this in C? I wouldn't! The thing is, in C, you have to allocate the memory in which to place the characters you read in? How many characters? You don't know ahead of time. If you allocate too few characters, you will have to allocate a new buffer every time to realize you reading more characters than you made room for. If you over-allocate, you are wasting space.

C is a language for low-level programming. If you are new to programming and writing simple applications for reading files line-by-line, just use C++. It does all that memory allocation for you.

Your later questions regarding "\0" and end-of-lines in general were answered by others and do apply to C as well as C++. But if you are using C, please remember that it's not just the end-of-line that matters, but memory allocation as well. And you will have to be careful not to overrun your buffer.

Watermark / hint text / placeholder TextBox


    <Style x:Key="TextBoxUserStyle" BasedOn="{x:Null}" TargetType="{x:Type TextBox}">
      <Setter Property="Foreground" Value="Black"/>
      <Setter Property="HorizontalAlignment" Value="Center"/>
      <Setter Property="VerticalContentAlignment" Value="Center"/>
      <Setter Property="Width" Value="225"/>
      <Setter Property="Height" Value="25"/>
      <Setter Property="FontSize" Value="12"/>
      <Setter Property="Padding" Value="1"/>
      <Setter Property="Margin" Value="5"/>
      <Setter Property="AllowDrop" Value="true"/>
      <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
      <Setter Property="Template">
          <ControlTemplate TargetType="{x:Type TextBox}">
            <Border x:Name="OuterBorder" BorderBrush="#5AFFFFFF" BorderThickness="1,1,1,1" CornerRadius="4,4,4,4">
              <Border x:Name="InnerBorder" Background="#FFFFFFFF" BorderBrush="#33000000" BorderThickness="1,1,1,1" CornerRadius="3,3,3,3">
                <ScrollViewer SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" x:Name="PART_ContentHost"/>

    <Style x:Key="PasswordBoxVistaStyle" BasedOn="{x:Null}" TargetType="{x:Type PasswordBox}">
      <Setter Property="Foreground" Value="Black"/>
      <Setter Property="HorizontalAlignment" Value="Center"/>
      <Setter Property="VerticalContentAlignment" Value="Center"/>
      <Setter Property="Width" Value="225"/>
      <Setter Property="Height" Value="25"/>
      <Setter Property="FontSize" Value="12"/>
      <Setter Property="Padding" Value="1"/>
      <Setter Property="Margin" Value="5"/>
      <Setter Property="AllowDrop" Value="true"/>
      <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
      <Setter Property="Template">
          <ControlTemplate TargetType="{x:Type PasswordBox}">
            <Border x:Name="OuterBorder" BorderBrush="#5AFFFFFF" BorderThickness="1,1,1,1" CornerRadius="4,4,4,4">
              <Border x:Name="InnerBorder" Background="#FFFFFFFF" BorderBrush="#33000000" BorderThickness="1,1,1,1" CornerRadius="3,3,3,3">
                  <Label x:Name="lblPwd" Content="Password" FontSize="11" VerticalAlignment="Center" Margin="2,0,0,0" FontFamily="Verdana" Foreground="#828385" Padding="0"/>
                  <ScrollViewer SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" x:Name="PART_ContentHost"/>
              <Trigger Property="IsFocused" Value="True">
                <Setter Property="Visibility" TargetName="lblPwd" Value="Hidden"/>

        <PasswordBox Style="{StaticResource PasswordBoxVistaStyle}" Margin="169,143,22,0" Name="txtPassword" FontSize="14" TabIndex="2" Height="31" VerticalAlignment="Top" />

This can help check it with your code.When applied to password box,it will show Password,which will disappear when usertypes.

How to return a custom object from a Spring Data JPA GROUP BY query

define a custom pojo class say sureveyQueryAnalytics and store the query returned value in your custom pojo class

@Query(value = "select new, count(sv)) from Survey s group by s.answer")
List<SureveyQueryAnalytics> calculateSurveyCount();

How to get the file path from URI?

Here is the answer to the question here

Actually we have to get it from the sharable ContentProvider of Camera Application.

EDIT . Copying answer that worked for me

private String getRealPathFromURI(Uri contentUri) {
String[] proj = { MediaStore.Images.Media.DATA };
CursorLoader loader = new CursorLoader(mContext, contentUri, proj, null, null, null);
Cursor cursor = loader.loadInBackground();
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
String result = cursor.getString(column_index);
return result;


Delete specific line number(s) from a text file using sed?

You can delete a particular single line with its line number by

sed -i '33d' file

This will delete the line on 33 line number and save the updated file.

How do I detect if software keyboard is visible on Android Device or not?

There is a direct method to find this out. And, it does not require the layout changes.
So it works in immersive fullscreen mode, too.
But, unfortunately, it does not work on all devices. So you have to test it with your device(s).

The trick is that you try to hide or show the soft keyboard and capture the result of that try.
If it works correct then the keyboard is not really shown or hidden. We just ask for the state.

To stay up-to-date, you simply repeat this operation, e.g. every 200 milliseconds, using a Handler.

The implementation below does just a single check.
If you do multiple checks, then you should enable all the (_keyboardVisible) tests.

public interface OnKeyboardShowHide
    void    onShowKeyboard( Object param );
    void    onHideKeyboard( Object param );

private static Handler      _keyboardHandler    = new Handler();
private boolean             _keyboardVisible    = false;
private OnKeyboardShowHide  _keyboardCallback;
private Object              _keyboardCallbackParam;

public void start( OnKeyboardShowHide callback, Object callbackParam )
    _keyboardCallback      = callback;
    _keyboardCallbackParam = callbackParam;
    View view = getCurrentFocus();
    if (view != null)
        InputMethodManager imm = (InputMethodManager) getSystemService( Activity.INPUT_METHOD_SERVICE );
        imm.hideSoftInputFromWindow( view.getWindowToken(), InputMethodManager.HIDE_IMPLICIT_ONLY, _keyboardResultReceiver );
        imm.showSoftInput( view, InputMethodManager.SHOW_IMPLICIT, _keyboardResultReceiver );
    else // if (_keyboardVisible)
        _keyboardVisible = false;
        _keyboardCallback.onHideKeyboard( _keyboardCallbackParam );

private ResultReceiver      _keyboardResultReceiver = new ResultReceiver( _keyboardHandler )
    protected void onReceiveResult( int resultCode, Bundle resultData )
        switch (resultCode)
            case InputMethodManager.RESULT_SHOWN :
            case InputMethodManager.RESULT_UNCHANGED_SHOWN :
                // if (!_keyboardVisible)
                    _keyboardVisible = true;
                    _keyboardCallback.onShowKeyboard( _keyboardCallbackParam );
            case InputMethodManager.RESULT_HIDDEN :
            case InputMethodManager.RESULT_UNCHANGED_HIDDEN :
                // if (_keyboardVisible)
                    _keyboardVisible = false;
                    _keyboardCallback.onHideKeyboard( _keyboardCallbackParam );

How to include js and CSS in JSP with spring MVC

If you using java-based annotation you can do this:

    public void addResourceHandlers(ResourceHandlerRegistry registry) {

Where static folder


How to check if $? is not equal to zero in unix shell scripting?

function assert_exit_code {
    rc=$?; if [[ $rc != 0 ]]; then echo "$1" 1>&2; fi


assert_exit_code " has failed"

Eclipse will not open due to environment variables

Copy jre folder present in "C:\Program Files\Java\" directory into eclipse folder.. i.e, C:\eclipse\

Script Tag - async & defer

Both async and defer scripts begin to download immediately without pausing the parser and both support an optional onload handler to address the common need to perform initialization which depends on the script.

The difference between async and defer centers around when the script is executed. Each async script executes at the first opportunity after it is finished downloading and before the window’s load event. This means it’s possible (and likely) that async scripts are not executed in the order in which they occur in the page. Whereas the defer scripts, on the other hand, are guaranteed to be executed in the order they occur in the page. That execution starts after parsing is completely finished, but before the document’s DOMContentLoaded event.

Source & further details: here.

How to send FormData objects with Ajax-requests in jQuery?


function submitForm() {
    var data1 = new FormData($('input[name^="file"]'));
    $.each($('input[name^="file"]')[0].files, function(i, file) {
        data1.append(i, file);

        url: "<?php echo base_url() ?>employee/dashboard2/test2",
        type: "POST",
        data: data1,
        enctype: 'multipart/form-data',
        processData: false, // tell jQuery not to process the data
        contentType: false // tell jQuery not to set contentType
    }).done(function(data) {
        console.log("PHP Output:");
    return false;


public function upload_file() {
    foreach($_FILES as $key) {
        $name = time().$key['name'];
        $path = 'upload/'.$name;
        @move_uploaded_file($key['tmp_name'], $path);

Escape curly brace '{' in String.Format

Use double braces {{ or }} so your code becomes:

sb.AppendLine(String.Format("public {0} {1} {{ get; private set; }}", 
prop.Type, prop.Name));

// For prop.Type of "Foo" and prop.Name of "Bar", the result would be:
// public Foo Bar { get; private set; }

PHPUnit assert that an exception was thrown?

require_once 'PHPUnit/Framework.php';

class ExceptionTest extends PHPUnit_Framework_TestCase
    public function testException()
        // or for PHPUnit < 5.2
        // $this->setExpectedException(InvalidArgumentException::class);

        //...and then add your test code that generates the exception 

expectException() PHPUnit documentation

PHPUnit author article provides detailed explanation on testing exceptions best practices.

An error occurred while collecting items to be installed (Access is denied)

In my case I entered:

Error Log - found "An error occurred while collecting items to be installed" - right click and select "Open Log". From there I know what goues wrong(in my case PMD). I solve the problem in one project and all works ok.

How to get the title of HTML page with JavaScript?

Can use getElementsByTagName

var x = document.getElementsByTagName("title")[0];


// or


// or


Edits as suggested by Paul

How to pass data using NotificationCenter in swift 3.0 and NSNotificationCenter in swift 2.0?

this is how I implement it .

let dictionary = self.convertStringToDictionary(responceString)         NSNotification.Name(rawValue: "SOCKET_UPDATE"), object: dictionary)

Make a bucket public in Amazon S3

Amazon provides a policy generator tool:

After that, you can enter the policy requirements for the bucket on the AWS console:

Pass by Reference / Value in C++

I'm not sure if I understand your question correctly. It is a bit unclear. However, what might be confusing you is the following:

  1. When passing by reference, a reference to the same object is passed to the function being called. Any changes to the object will be reflected in the original object and hence the caller will see it.

  2. When passing by value, the copy constructor will be called. The default copy constructor will only do a shallow copy, hence, if the called function modifies an integer in the object, this will not be seen by the calling function, but if the function changes a data structure pointed to by a pointer within the object, then this will be seen by the caller due to the shallow copy.

I might have mis-understood your question, but I thought I would give it a stab anyway.

How to convert int[] into List<Integer> in Java?

In Java 8 with stream:

int[] ints = {1, 2, 3};
List<Integer> list = new ArrayList<Integer>();

or with Collectors

List<Integer> list =;

Writing a dictionary to a csv file with one line for every 'key: value'

Have you tried to add the "s" on: w.writerow(mydict) like this: w.writerows(mydict)? This issue happened to me but with lists, I was using singular instead of plural.

How to get all files under a specific directory in MATLAB?

You're looking for dir to return the directory contents.

To loop over the results, you can simply do the following:

dirlist = dir('.');
for i = 1:length(dirlist)

This should give you output in the following format, e.g.:

name: 'my_file'
date: '01-Jan-2010 12:00:00'
bytes: 56
isdir: 0
datenum: []

What are and is a programmer-defined file and is used by automake to generate the file (the .am stands for automake). The configure script typically seen in source tarballs will use the to generate a Makefile.

The configure script itself is generated from a programmer-defined file named either or (deprecated). I prefer .ac (for autoconf) since it differentiates it from the generated files and that way I can have rules such as make dist-clean which runs rm -f *.in. Since it is a generated file, it is not typically stored in a revision system such as Git, SVN, Mercurial or CVS, rather the .ac file would be.

Read more on GNU Autotools. Read about make and Makefile first, then learn about automake, autoconf, libtool, etc.

How to redirect stderr to null in cmd.exe

Your DOS command 2> nul

Read page Using command redirection operators. Besides the "2>" construct mentioned by Tanuki Software, it lists some other useful combinations.

Show "loading" animation on button click

        beforeSend : function(xhr, opts){
            //show loading gif
        success: function(){

        complete : function() {
           //remove loading gif

EF Core add-migration Build Failed

It's because of other projects in your solutions. e.g If you have two projects in your solution as Project A and Project B. If Project A is not successful build and then Project B data migration will fail. So you should unload Project A and add the migration to Project B again.

I think this is not a good answer but hope this help.

How to run Gulp tasks sequentially one after the other

I was searching for this answer for a while. Now I got it in the official gulp documentation.

If you want to perform a gulp task when the last one is complete, you have to return a stream:

gulp.task('wiredep', ['dev-jade'], function () {_x000D_
    var stream = gulp.src(paths.output + '*.html')_x000D_
    return stream; // execute next task when this is completed_x000D_
// First will execute and complete wiredep task_x000D_
gulp.task('prod-jade', ['wiredep'], function() {_x000D_
    gulp.src(paths.output + '**/*.html')_x000D_

Allow anonymous authentication for a single folder in web.config?

To make it work I build my directory like this:

Project Public Restrict

So I edited my webconfig for my public folder:

<location path="Project/Public">
        <allow users="?"/>

And for my Restricted folder:

 <location path="Project/Restricted">
        <allow users="*"/>

See here for the spec of * and ?:

I hope I have helped.

Firing events on CSS class changes in jQuery

I would suggest you override the addClass function. You can do it this way:

// Create a closure
    // Your base, I'm in it!
    var originalAddClassMethod = jQuery.fn.addClass;

    jQuery.fn.addClass = function(){
        // Execute the original method.
        var result = originalAddClassMethod.apply( this, arguments );

        // call your function
        // this gets called everytime you use the addClass method

        // return the original result
        return result;

// document ready function
    // do stuff

IE9 jQuery AJAX with CORS returns "Access is denied"

To solve this problem, also check if you have some included .js into your ajax file called: I received Access denied error while including shadowbox.js in my ajax.php

How to re-enable right click so that I can inspect HTML elements in Chrome?

You could use javascript:void(document.oncontextmenu=null); open Browser console and run the code above. It will turn off blockin' of mouse right button

Copy data into another table

Insert Selected column with condition

INSERT INTO where_to_insert (col_1,col_2) SELECT col1, col2 FROM from_table WHERE condition;

Copy all data from one table to another with the same column name.

INSERT INTO where_to_insert 
SELECT * FROM from_table WHERE condition;

py2exe - generate single executable file

As the other poster mention, py2exe, will generate an executable + some libraries to load. You can also have some data to add to your program.

Next step is to use an installer, to package all this into one easy-to-use installable/unistallable program.

I have used InnoSetup with delight for several years and for commercial programs, so I heartily recommend it.

Saving binary data as file using JavaScript from a browser


let bytes = [65,108,105,99,101,39,115,32,65,100,118,101,110,116,117,114,101];_x000D_
let base64data = btoa(String.fromCharCode.apply(null, bytes));_x000D_
let a = document.createElement('a');_x000D_
a.href = 'data:;base64,' + base64data;_x000D_ = 'binFile.txt'; _x000D_;

I convert here binary data to base64 (for bigger data conversion use this) - during downloading browser decode it automatically and save raw data in file. 2020.06.14 I upgrade Chrome to 83.0 and above SO snippet stop working (probably due to sandbox security restrictions) - but JSFiddle version works - here

ggplot geom_text font size control

Here are a few options for changing text / label sizes


# Example data using mtcars

a <- aggregate(mpg ~ vs + am , mtcars, function(i) round(mean(i)))

p <- ggplot(mtcars, aes(factor(vs), y=mpg, fill=factor(am))) + 
            geom_bar(stat="identity",position="dodge") + 
            geom_text(data = a, aes(label = mpg), 
                            position = position_dodge(width=0.9),  size=20)

The size in the geom_text changes the size of the geom_text labels.

p <- p + theme(axis.text = element_text(size = 15)) # changes axis labels

p <- p + theme(axis.title = element_text(size = 25)) # change axis titles

p <- p + theme(text = element_text(size = 10)) # this will change all text size 
                                                             # (except geom_text)

For this And why size of 10 in geom_text() is different from that in theme(text=element_text()) ?

Yes, they are different. I did a quick manual check and they appear to be in the ratio of ~ (14/5) for geom_text sizes to theme sizes.

So a horrible fix for uniform sizes is to scale by this ratio

geom.text.size = 7
theme.size = (14/5) * geom.text.size

ggplot(mtcars, aes(factor(vs), y=mpg, fill=factor(am))) + 
  geom_bar(stat="identity",position="dodge") + 
  geom_text(data = a, aes(label = mpg), 
            position = position_dodge(width=0.9),  size=geom.text.size) + 
  theme(axis.text = element_text(size = theme.size, colour="black")) 

This of course doesn't explain why? and is a pita (and i assume there is a more sensible way to do this)

GridView VS GridLayout in Android Apps

A GridView is a ViewGroup that displays items in two-dimensional scrolling grid. The items in the grid come from the ListAdapter associated with this view.

This is what you'd want to use (keep using). Because a GridView gets its data from a ListAdapter, the only data loaded in memory will be the one displayed on screen. GridViews, much like ListViews reuse and recycle their views for better performance.

Whereas a GridLayout is a layout that places its children in a rectangular grid.

It was introduced in API level 14, and was recently backported in the Support Library. Its main purpose is to solve alignment and performance problems in other layouts. Check out this tutorial if you want to learn more about GridLayout.

JRE installation directory in Windows

In the command line you can type java -version

using href links inside <option> tag

    <select name="career" id="career" onchange="location = this.value;">
        <option value="resume" selected> All Applications </option>
        <option value="resume&j=14">Seo Expert</option>
        <option value="resume&j=21">Project Manager</option>
        <option value="resume&j=33">Php Developer</option>

C# List<string> to string with delimiter

You can also do this with linq if you'd like

var names = new List<string>() { "John", "Anna", "Monica" };
var joinedNames = names.Aggregate((a, b) => a + ", " + b);

Although I prefer the non-linq syntax in Quartermeister's answer and I think Aggregate might perform slower (probably more string concatenation operations).

How do you cast a List of supertypes to a List of subtypes?

class MyClass {
  String field;

  MyClass(String field) {
    this.field = field;

public void testTypeCast() {
  List<Object> objectList = Arrays.asList(new MyClass("1"), new MyClass("2"));

  Class<MyClass> clazz = MyClass.class;
  List<MyClass> myClassList =

  assertEquals(objectList.size(), myClassList.size());
  assertEquals(objectList, myClassList);

This test shows how to cast List<Object> to List<MyClass>. But you need to take an attention to that objectList must contain instances of the same type as MyClass. And this example can be considered when List<T> is used. For this purpose get field Class<T> clazz in constructor and use it instead of MyClass.class.

How can I get the domain name of my site within a Django template?

If you use the "request" context processor, and are using the Django sites framework, and have the Site middleware installed (i.e. your settings include these):



... then you will have the request object available in templates, and it will contain a reference to the current Site for the request as You can then retrieve the domain in a template with:


and the site name with:


How to search if dictionary value contains certain string with Python

Following is one liner for accepted answer ... (for one line lovers ..)

def search_dict(my_dict,searchFor):
    s_val = [[ k if searchFor in v else None for v in my_dict[k]] for k in my_dict]    
    return s_val

How to determine an object's class?

if (obj instanceof C) {
//your code

Make div 100% Width of Browser Window

Try to give it a postion: absolute;

How to do "If Clicked Else .."

This is all you need:

Having an "else" doesn't apply in this scenario, else would mean "did not click", in which case you just wouldn't do anything.

What is the default encoding of the JVM?

It's going to be locale-dependent. Different locale, different default encoding.

What is difference between cacerts and keystore?

'cacerts' is a truststore. A trust store is used to authenticate peers. A keystore is used to authenticate yourself.

How to read a string one letter at a time in python

# Retain a map of the Morse code
conversion = {}

# Read map from file, add it to the datastructure
morseCodeFile = file('morseCode.txt')
for line in moreCodeFile:
    conversion[line[0]] = line[2:]

# Ask for input from the user
s = raw_input("Please enter string to translate")
# Go over each character, and print it the translation.
# Defensive programming: do something sane if the user 
# inputs non-Morse compatible strings.    
for c in s:
    print conversion.get(c, "No translation for "+c)

Is Django for the frontend or backend?


Django is a framework, not a language. Python is the language in which Django is written.

Django is a collection of Python libs allowing you to quickly and efficiently create a quality Web application, and is suitable for both frontend and backend.

However, Django is pretty famous for its "Django admin", an auto generated backend that allows you to manage your website in a blink for a lot of simple use cases without having to code much.

More precisely, for the front end, Django helps you with data selection, formatting, and display. It features URL management, a templating language, authentication mechanisms, cache hooks, and various navigation tools such as paginators.

For the backend, Django comes with an ORM that lets you manipulate your data source with ease, forms (an HTML independent implementation) to process user input and validate data and signals, and an implementation of the observer pattern. Plus a tons of use-case specific nifty little tools.

For the rest of the backend work Django doesn't help with, you just use regular Python. Business logic is a pretty broad term.

You probably want to know as well that Django comes with the concept of apps, a self contained pluggable Django library that solves a problem. The Django community is huge, and so there are numerous apps that do specific business logic that vanilla Django doesn't.

How do I select between the 1st day of the current month and current day in MySQL?

select * from table
where date between 
(date_add (CURRENT_DATE, INTERVAL(1 - DAYOFMonth(CURRENT_DATE)) day)) and current_date;

"Could not find acceptable representation" using spring-boot-starter-web

I had to explicitly call out the dependency for my json library in my POM.

Once I added the below dependency, it all worked.


Getting Class type from String

Not sure what you are asking, but... Class.forname, maybe?

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

Do this:

date('Y-m-d', strtotime('dd/mm/yyyy'));

But make sure 'dd/mm/yyyy' is the actual date.

How to change Label Value using javascript

very simple

$('#label-ID').text("label value which you want to set");

How do I add more members to my ENUM-type column in MySQL?

FYI: A useful simulation tool - phpMyAdmin with Wampserver 3.0.6 - Preview SQL: I use 'Preview SQL' to see the SQL code that would be generated before you save the column with the change to ENUM. Preview SQL

Above you see that I have entered 'Ford','Toyota' into the ENUM but I am getting syntax ENUM(0) which is generating syntax error Query error 1064#

I then copy and paste and alter the SQL and run it through SQL with a positive result.

SQL changed

This is a quickfix that I use often and can also be used on existing ENUM values that need to be altered. Thought this might be useful.

Node.js for() loop returning the same values at each loop

  for(var i = 0; i < BoardMessages.length;i++){
            console.log("Loading message %d".green, j);
            htmlMessageboardString += MessageToHTMLString(BoardMessages[j]);

That should work; however, you should never create a function in a loop. Therefore,

  for(var i = 0; i < BoardMessages.length;i++){

  function composeMessage(message){
      console.log("Loading message %d".green, message);
      htmlMessageboardString += MessageToHTMLString(message);

How can I access Oracle from Python?

Here's what worked for me. My Python and Oracle versions are slightly different from yours, but the same approach should apply. Just make sure the cx_Oracle binary installer version matches your Oracle client and Python versions.

My versions:

  • Python 2.7
  • Oracle Instant Client 11G R2
  • cx_Oracle 5.0.4 (Unicode, Python 2.7, Oracle 11G)
  • Windows XP SP3


  1. Download the Oracle Instant Client package. I used Unzip it to C:\your\path\to\instantclient_11_2
  2. Download and run the cx_Oracle binary installer. I used cx_Oracle-5.0.4-11g-unicode.win32-py2.7.msi. I installed it for all users and pointed it to the Python 2.7 location it found in the registry.
  3. Set the ORACLE_HOME and PATH environment variables via a batch script or whatever mechanism makes sense in your app context, so that they point to the Oracle Instant Client directory. See oracle_python.bat source below. I'm sure there must be a more elegant solution for this, but I wanted to limit my system-wide changes as much as possible. Make sure you put the targeted Oracle Instant Client directory at the beginning of the PATH (or at least ahead of any other Oracle client directories). Right now, I'm only doing command-line stuff so I just run oracle_python.bat in the shell before running any programs that require cx_Oracle.
  4. Run regedit and check to see if there's an NLS_LANG key set at \HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE. If so, rename the key (I changed it to NLS_LANG_OLD) or unset it. This key should only be used as the default NLS_LANG value for Oracle 7 client, so it's safe to remove it unless you happen to be using Oracle 7 client somewhere else. As always, be sure to backup your registry before making changes.
  5. Now, you should be able to import cx_Oracle in your Python program. See the source below. Note that I had to set the connection and SQL strings to Unicode for my version of cx_Oracle.

Source: oracle_python.bat

@echo off
set ORACLE_HOME=C:\your\path\to\instantclient_11_2


import cx_Oracle

conn_str = u'user/password@host:port/service'
conn = cx_Oracle.connect(conn_str)
c = conn.cursor()
c.execute(u'select your_col_1, your_col_2 from your_table')
for row in c:
    print row[0], "-", row[1]

Possible Issues:

  • "ORA-12705: Cannot access NLS data files or invalid environment specified" - I ran into this before I made the NLS_LANG registry change.
  • "TypeError: argument 1 must be unicode, not str" - if you need to set the connection string to Unicode.
  • "TypeError: expecting None or a string" - if you need to set the SQL string to Unicode.
  • "ImportError: DLL load failed: The specified procedure could not be found." - may indicate that cx_Oracle can't find the appropriate Oracle client DLL.

Open Source Alternatives to Reflector?

I am currently working on an open-source disassembler / decompiler called Assembly Analyzer. It generates source code for methods, displays assembly metadata and resources, and allows you to walk through dependencies.

The project is hosted on CodePlex =>

Postgresql Windows, is there a default password?

Try this:

Open PgAdmin -> Files -> Open pgpass.conf

You would get the path of pgpass.conf at the bottom of the window. Go to that location and open this file, you can find your password there.


If the above does not work, you may consider trying this:

 1. edit pg_hba.conf to allow trust authorization temporarily
 2. Reload the config file (pg_ctl reload)
 3. Connect and issue ALTER ROLE / PASSWORD to set the new password
 4. edit pg_hba.conf again and restore the previous settings
 5. Reload the config file again

How (and why) to use display: table-cell (CSS)

How (and why) to use display: table-cell (CSS)

I just wanted to mention, since I don't think any of the other answers did directly, that the answer to "why" is: there is no good reason, and you should probably never do this.

In my over a decade of experience in web development, I can't think of a single time I would have been better served to have a bunch of <div>s with display styles than to just have table elements.

The only hypothetical I could come up with is if you have tabular data stored in some sort of non-HTML-table format (eg. a CSV file). In a very specific version of this case it might be easier to just add <div> tags around everything and then add descendent-based styles, instead of adding actual table tags.

But that's an extremely contrived example, and in all real cases I know of simply using table tags would be better.

Already defined in .obj - no double inclusions

You probably don't want to do this:

#include "client.cpp"

A *.cpp file will have been compiled by the compiler as part of your build. By including it in other files, it will be compiled again (and again!) in every file in which you include it.

Now here's the thing: You are guarding it with #ifndef SOCKET_CLIENT_CLASS, however, each file that has #include "client.cpp" is built independently and as such will find SOCKET_CLIENT_CLASS not yet defined. Therefore it's contents will be included, not #ifdef'd out.

If it contains any definitions at all (rather than just declarations) then these definitions will be repeated in every file where it's included.

Excel VBA code to copy a specific string to clipboard

This macro uses late binding to copy text to the clipboard without requiring you to set references. You should be able to just paste and go:

Sub CopyText(Text As String)
    'VBA Macro using late binding to copy text to clipboard.
    'By Justin Kay, 8/15/2014
    Dim MSForms_DataObject As Object
    Set MSForms_DataObject = CreateObject("new:{1C3B4210-F441-11CE-B9EA-00AA006B1A69}")
    MSForms_DataObject.SetText Text
    Set MSForms_DataObject = Nothing
End Sub


Sub CopySelection()
    CopyText Selection.Text
End Sub

Using the rJava package on Win7 64 bit with R

Getting rJava to work depends heavily on your computers configuration:

  1. You have to use the same 32bit or 64bit version for both: R and JDK/JRE. A mixture of this will never work (at least for me).
  2. If you use 64bit version make sure, that you do not set JAVA_HOME as a enviorment variable. If this variable is set, rJava will not work for whatever reason (at least for me). You can check easily within R is JAVA_HOME is set with


If you need to have JAVA_HOME set (e.g. you need it for maven or something else), you could deactivate it within your R-session with the following code before loading rJava:

if (Sys.getenv("JAVA_HOME")!="")

This should do the trick in most cases. Furthermore this will fix issue Using the rJava package on Win7 64 bit with R, too. I borrowed the idea of unsetting the enviorment variable from R: rJava package install failing.

Passing a string array as a parameter to a function java

I believe this should be the way this is done...

public void function(String [] array){

And the calling will be done like...

public void test(){
    String[] stringArray = {"a","b","c","d","e","f","g","h","t","k","k","k","l","k"};

Python check if website exists

It's better to check that status code is < 400, like it was done here. Here is what do status codes mean (taken from wikipedia):

  • 1xx - informational
  • 2xx - success
  • 3xx - redirection
  • 4xx - client error
  • 5xx - server error

If you want to check if page exists and don't want to download the whole page, you should use Head Request:

import httplib2
h = httplib2.Http()
resp = h.request("", 'HEAD')
assert int(resp[0]['status']) < 400

taken from this answer.

If you want to download the whole page, just make a normal request and check the status code. Example using requests:

import requests

response = requests.get('')
assert response.status_code < 400

See also similar topics:

Hope that helps.

Notepad++ add to every line

Well, I am posting this after such a long time but this will the easiest of all.

  1. To add text at the beginning/a-certain-place-from-start for all lines, just click there and do ALT+C and you will get the below box. Type in your text and click OK and it's done.

    enter image description here

  2. To add a certain text at end of all lines, do CTRL+F, and choose REPLACE. You will get the below box. Put in '$' in 'find what' and in 'replace with' type in your text.Make sure you choose 'regular expression' in the search mode (left down). Finally click 'replace all' and you are done.

enter image description here

How to get a DOM Element from a JQuery Selector

I needed to get the element as a string.


Which will give you something like:

<input type="text" id="bob" value="hello world" /> a string rather than a DOM element.

JavaScript closures vs. anonymous functions

After inspecting closely, looks like both of you are using closure.

In your friends case, i is accessed inside anonymous function 1 and i2 is accessed in anonymous function 2 where the console.log is present.

In your case you are accessing i2 inside anonymous function where console.log is present. Add a debugger; statement before console.log and in chrome developer tools under "Scope variables" it will tell under what scope the variable is.

How do you enable mod_rewrite on any OS?

if it related to hosting site then ask to your hosting or if you want to enable it in local machine then check this youtube step by step tutorial related to enabling rewrite module in wamp apache
Wamp server icon -> Apache -> Apache Modules and check the rewrite module option it should be checked but after that wamp require restart all services

Use of String.Format in JavaScript?

//Add "format" method to the string class
//supports:  "Welcome {0}. You are the first person named {0}".format("David");
//       and "First Name:{} Last name:{}".format("David","Wazy");
//       and "Value:{} size:{0} shape:{1} weight:{}".format(value, size, shape, weight)
String.prototype.format = function () {
    var content = this;
    for (var i = 0; i < arguments.length; i++) {
        var target = '{' + i + '}';
        content = content.replace("{}", String(arguments[i]));
    return content;
alert("I {} this is what {2} want and {} works for {2}!".format("hope","it","you"))

You can mix and match using positional and "named" replacement locations using this function.

How to send PUT, DELETE HTTP request in HttpURLConnection?

UrlConnection is an awkward API to work with. HttpClient is by far the better API and it'll spare you from loosing time searching how to achieve certain things like this stackoverflow question illustrates perfectly. I write this after having used the jdk HttpUrlConnection in several REST clients. Furthermore when it comes to scalability features (like threadpools, connection pools etc.) HttpClient is superior

org.xml.sax.SAXParseException: Premature end of file for *VALID* XML

If input stream is not closed properly then this exception may happen. make sure : If inputstream used is not used "Before" in some way then where you are intended to read. i.e if read 2nd time from same input stream in single operation then 2nd call will get this exception. Also make sure to close input stream in finally block or something like that.

eslint: error Parsing error: The keyword 'const' is reserved

In my case, it was unable to find the .eslintrc file so I copied from node_modules/.bin to root.

Get key and value of object in JavaScript?

If this is all the object is going to store, then best literal would be

var top_brands = {
    'Adidas' : 100,
    'Nike'   : 50

Then all you need is a loop.

for (var key in top_brands){
    console.log(key, top_brands[key]);

phpMyAdmin says no privilege to create database, despite logged in as root user

My problem was on my KSWEB app that I downloaded. I am having no privileges error, but when I opened my and changed

$cfg['Servers'][$i]['auth_type'] = 'cookie';


$cfg['Servers'][$i]['auth_type'] = 'config';

It worked and I now have privileges to create a database.

How to read the content of a file to a string in C?

Note: This is a modification of the accepted answer above.

Here's a way to do it, complete with error checking.

I've added a size checker to quit when file was bigger than 1 GiB. I did this because the program puts the whole file into a string which may use too much ram and crash a computer. However, if you don't care about that you could just remove it from the code.

#include <stdio.h>
#include <stdlib.h>

#define FILE_OK 0
#define FILE_NOT_EXIST 1
#define FILE_TO_LARGE 2

char * c_read_file(const char * f_name, int * err, size_t * f_size) {
    char * buffer;
    size_t length;
    FILE * f = fopen(f_name, "rb");
    size_t read_length;
    if (f) {
        fseek(f, 0, SEEK_END);
        length = ftell(f);
        fseek(f, 0, SEEK_SET);
        // 1 GiB; best not to load a whole large file in one string
        if (length > 1073741824) {
            *err = FILE_TO_LARGE;
            return NULL;
        buffer = (char *)malloc(length + 1);
        if (length) {
            read_length = fread(buffer, 1, length, f);
            if (length != read_length) {
                 *err = FILE_READ_ERROR;

                 return NULL;
        *err = FILE_OK;
        buffer[length] = '\0';
        *f_size = length;
    else {
        *err = FILE_NOT_EXIST;
        return NULL;
    return buffer;

And to check for errors:

int err;
size_t f_size;
char * f_data;

f_data = c_read_file("test.txt", &err, &f_size);

if (err) {
    // process error
else {
    // process data

How to enable CORS in flask

If you want to enable CORS for all routes, then just install flask_cors extension (pip3 install -U flask_cors) and wrap app like this: CORS(app).

That is enough to do it (I tested this with a POST request to upload an image, and it worked for me):

from flask import Flask
from flask_cors import CORS
app = Flask(__name__)
CORS(app) # This will enable CORS for all routes

Important note: if there is an error in your route, let us say you try to print a variable that does not exist, you will get a CORS error related message which, in fact, has nothing to do with CORS.

How to verify an XPath expression in Chrome Developers tool or Firefox's Firebug?

By using Chrome or Opera

without any plugins, without writing any single XPath syntax character

  1. right click the required element, then "inspect"
  2. right click on highlighted element tag, choose Copy ? Copy XPath.


Enter image description here

Default value in an mvc view model

In case you need to post the same model to server the solution with having default bool value in constructor would not be viable for you. Let's imagine that you have following model:

public class SearchModel
    public bool IsMale { get; set; }

    public SearchModel()
        IsMale = true;

On view you would have something like this:

@Html.CheckBoxFor(n => n.IsMale)

The problem is when user uncheck this checkbox and post it to the server - you would end up with default value set up in constructor (which in this case is true).

So in this case I would end up with just specifying default value on view:

@Html.CheckBoxFor(n => n.IsMale, new { @checked = "checked" })

Define variable to use with IN operator (T-SQL)

DECLARE @myList TABLE (Id BIGINT) INSERT INTO @myList(Id) VALUES (1),(2),(3),(4);
select * from myTable where myColumn in(select Id from @myList)

Please note that for long list or production systems it's not recommended to use this way as it may be much more slower than simple INoperator like someColumnName in (1,2,3,4) (tested using 8000+ items list)

Create a button programmatically and set a background image

SWIFT 3 Version of Alex Reynolds' Answer

let image = UIImage(named: "name") as UIImage?
let button = UIButton(type: UIButtonType.custom) as UIButton
button.frame = CGRect(x: 100, y: 100, width: 100, height: 100)
button.setImage(image, for: .normal)
button.addTarget(self, action: Selector("btnTouched:"), for:.touchUpInside)

How can I kill all sessions connecting to my oracle database?


startup force;

Brutal, yet elegant.

Is it possible to put a ConstraintLayout inside a ScrollView?

There was a bug with ConstraintLayout inside ScrollViews and it has been fixed. google has fixed the bug in Android Studio 2.2 Preview 2 (constraintlayout 1.0.0-alpha2).

Check this link for new update (Preview 2): works properly inside ScrollView and RecycleView

Solution 1:

The solution was to use android:fillViewport="true" on the ScrollView

Solution 2:

Use NestedScrollView instead of ScrollView with android:fillViewport="true"

Edit - 09/16/20:

Currently, it is more usual to use the ScrollView with the ConstraintLayout height set to wrap_content, it works very well, don't forget the fillViewPort and that both Scroll and Nested support only one direct child.

Get url parameters from a string in .NET

Here's another alternative if, for any reason, you can't or don't want to use HttpUtility.ParseQueryString().

This is built to be somewhat tolerant to "malformed" query strings, i.e. http://test/test.html?empty= becomes a parameter with an empty value. The caller can verify the parameters if needed.

public static class UriHelper
    public static Dictionary<string, string> DecodeQueryParameters(this Uri uri)
        if (uri == null)
            throw new ArgumentNullException("uri");

        if (uri.Query.Length == 0)
            return new Dictionary<string, string>();

        return uri.Query.TrimStart('?')
                        .Split(new[] { '&', ';' }, StringSplitOptions.RemoveEmptyEntries)
                        .Select(parameter => parameter.Split(new[] { '=' }, StringSplitOptions.RemoveEmptyEntries))
                        .GroupBy(parts => parts[0],
                                 parts => parts.Length > 2 ? string.Join("=", parts, 1, parts.Length - 1) : (parts.Length > 1 ? parts[1] : ""))
                        .ToDictionary(grouping => grouping.Key,
                                      grouping => string.Join(",", grouping));


public class UriHelperTest
    public void DecodeQueryParameters()
        DecodeQueryParametersTest("http://test/test.html", new Dictionary<string, string>());
        DecodeQueryParametersTest("http://test/test.html?", new Dictionary<string, string>());
        DecodeQueryParametersTest("http://test/test.html?key=bla/blub.xml", new Dictionary<string, string> { { "key", "bla/blub.xml" } });
        DecodeQueryParametersTest("http://test/test.html?eins=1&zwei=2", new Dictionary<string, string> { { "eins", "1" }, { "zwei", "2" } });
        DecodeQueryParametersTest("http://test/test.html?empty", new Dictionary<string, string> { { "empty", "" } });
        DecodeQueryParametersTest("http://test/test.html?empty=", new Dictionary<string, string> { { "empty", "" } });
        DecodeQueryParametersTest("http://test/test.html?key=1&", new Dictionary<string, string> { { "key", "1" } });
        DecodeQueryParametersTest("http://test/test.html?key=value?&b=c", new Dictionary<string, string> { { "key", "value?" }, { "b", "c" } });
        DecodeQueryParametersTest("http://test/test.html?key=value=what", new Dictionary<string, string> { { "key", "value=what" } });
            new Dictionary<string, string>
                { "q", "energy+edge" },
                { "rls", "" },
                { "ie", "UTF-8" },
                { "oe", "UTF-8" },
                { "startIndex", "" },
                { "startPage", "1%22" },
        DecodeQueryParametersTest("http://test/test.html?key=value;key=anotherValue", new Dictionary<string, string> { { "key", "value,anotherValue" } });

    private static void DecodeQueryParametersTest(string uri, Dictionary<string, string> expected)
        Dictionary<string, string> parameters = new Uri(uri).DecodeQueryParameters();
        Assert.AreEqual(expected.Count, parameters.Count, "Wrong parameter count. Uri: {0}", uri);
        foreach (var key in expected.Keys)
            Assert.IsTrue(parameters.ContainsKey(key), "Missing parameter key {0}. Uri: {1}", key, uri);
            Assert.AreEqual(expected[key], parameters[key], "Wrong parameter value for {0}. Uri: {1}", parameters[key], uri);

Python regex to match dates

Sometimes we need to get the date from a string. One example with grouping:

record = '1518-09-06 00:57 some-alphanumeric-charecter'
pattern_date_time = ([0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}) .+
match = re.match(pattern_date_time, record)
if match is not None:
  group =
  date = group[0]
  print(date) // outputs 1518-09-06 00:57

Key value pairs using JSON

I see what you are trying to ask and I think this is the simplest answer to what you are looking for, given you might not know how many key pairs your are being sent.

Simple Key Pair JSON structure

var data = {
    'XXXXXX' : '100.0',
    'YYYYYYY' : '200.0',
    'ZZZZZZZ' : '500.0',

Usage JavaScript code to access the key pairs

for (var key in data) 
  { if (!data.hasOwnProperty(key))
    { continue; } 
    console.log(key + ' -> ' +  data[key]);

Console output should look like this

XXXXXX -> 100.0 
YYYYYYY -> 200.0 
ZZZZZZZ -> 500.0

Here is a JSFiddle to show how it works.

How does delete[] know it's an array?

Yes, the OS keeps some things in the 'background.' For example, if you run

int* num = new int[5];

the OS can allocate 4 extra bytes, store the size of the allocation in the first 4 bytes of the allocated memory and return an offset pointer (ie, it allocates memory spaces 1000 to 1024 but the pointer returned points to 1004, with locations 1000-1003 storing the size of the allocation). Then, when delete is called, it can look at 4 bytes before the pointer passed to it to find the size of the allocation.

I am sure that there are other ways of tracking the size of an allocation, but that's one option.

What causes the error "undefined reference to (some function)"?

It's a linker error. ld is the linker, so if you get an error message ending with "ld returned 1 exit status", that tells you that it's a linker error.

The error message tells you that none of the object files you're linking against contains a definition for avergecolumns. The reason for that is that the function you've defined is called averagecolumns (in other words: you misspelled the function name when calling the function (and presumably in the header file as well - otherwise you'd have gotten a different error at compile time)).

How to create <input type=“text”/> dynamically

Using Javascript, all you need is document.createElement and setAttribute.

var input = document.createElement("input");
input.setAttribute('type', 'text');

Then you can use appendChild to append the created element to the desired parent element.

var parent = document.getElementById("parentDiv");

How do I give text or an image a transparent background using CSS?

For a simple semi-transparent background color, the above solutions (CSS3 or bg images) are the best options. However, if you want to do something fancier (e.g. animation, multiple backgrounds, etc.), or if you don't want to rely on CSS3, you can try the “pane technique”:

.pane, .pane > .back, .pane > .cont { display: block; }

.pane {
    position: relative;

.pane > .back {
    position: absolute;
    width: 100%; height: 100%;
    top: auto; bottom: auto; left: auto; right: auto;

.pane > .cont {
    position: relative;
    z-index: 10;
<p class="pane">
    <span class="back" style="background-color: green; opacity: 0.6;"></span>
    <span class="cont" style="color: white;">Hello world</span>

The technique works by using two “layers” inside of the outer pane element:

  • one (the “back”) that fits the size of the pane element without affecting the flow of content,
  • and one (the “cont”) that contains the content and helps determine the size of the pane.

The position: relative on pane is important; it tells back layer to fit to the pane's size. (If you need the <p> tag to be absolute, change the pane from a <p> to a <span> and wrap all that in a absolutely-position <p> tag.)

The main advantage this technique has over similar ones listed above is that the pane doesn't have to be a specified size; as coded above, it will fit full-width (normal block-element layout) and only as high as the content. The outer pane element can be sized any way you please, as long as it's rectangular (i.e. inline-block will work; plain-old inline will not).

Also, it gives you a lot of freedom for the background; you're free to put really anything in the back element and have it not affect the flow of content (if you want multiple full-size sub-layers, just make sure they also have position: absolute, width/height: 100%, and top/bottom/left/right: auto).

One variation to allow background inset adjustment (via top/bottom/left/right) and/or background pinning (via removing one of the left/right or top/bottom pairs) is to use the following CSS instead:

.pane > .back {
    position: absolute;
    width: auto; height: auto;
    top: 0px; bottom: 0px; left: 0px; right: 0px;

As written, this works in Firefox, Safari, Chrome, IE8+, and Opera, although IE7 and IE6 require extra CSS and expressions, IIRC, and last time I checked, the second CSS variation does not work in Opera.

Things to watch out for:

  • Floating elements inside of the cont layer will not be contained. You'll need to make sure they are cleared or otherwise contained, or they'll slip out of the bottom.
  • Margins go on the pane element and padding goes on the cont element. Don't do use the opposite (margins on the cont or padding on the pane) or you'll discover oddities such as the page always being slightly wider than the browser window.
  • As mentioned, the whole thing needs to be block or inline-block. Feel free to use <div>s instead of <span>s to simplify your CSS.

A fuller demo, showing off the flexiblity of this technique by using it in tandem with display: inline-block, and with both auto & specific widths/min-heights:

.pane, .pane > .back, .pane > .cont { display: block; }_x000D_
.pane {_x000D_
 position: relative;_x000D_
 width: 175px; min-height: 100px;_x000D_
 margin: 8px;_x000D_
.pane > .back {_x000D_
 position: absolute; z-index: 1;_x000D_
 width: auto; height: auto;_x000D_
 top: 8px; bottom: 8px; left: 8px; right: 8px;_x000D_
.pane > .cont {_x000D_
 position: relative; z-index: 10;_x000D_
.debug_red { background: rgba(255, 0, 0, 0.5); border: 1px solid rgba(255, 0, 0, 0.75); }_x000D_
.debug_green { background: rgba(0, 255, 0, 0.5); border: 1px solid rgba(0, 255, 0, 0.75); }_x000D_
.debug_blue { background: rgba(0, 0, 255, 0.5); border: 1px solid rgba(0, 0, 255, 0.75); }
<p class="pane debug_blue" style="float: left;">_x000D_
 <span class="back debug_green"></span>_x000D_
 <span class="cont debug_red">_x000D_
  Pane content.<br/>_x000D_
  Pane content._x000D_
<p class="pane debug_blue" style="float: left;">_x000D_
 <span class="back debug_green"></span>_x000D_
 <span class="cont debug_red">_x000D_
  Pane content.<br/>_x000D_
  Pane content.<br/>_x000D_
  Pane content.<br/>_x000D_
  Pane content.<br/>_x000D_
  Pane content.<br/>_x000D_
  Pane content.<br/>_x000D_
  Pane content.<br/>_x000D_
  Pane content.<br/>_x000D_
  Pane content._x000D_
<p class="pane debug_blue" style="float: left; display: inline-block; width: auto;">_x000D_
 <span class="back debug_green"></span>_x000D_
 <span class="cont debug_red">_x000D_
  Pane content.<br/>_x000D_
  Pane content._x000D_
<p class="pane debug_blue" style="float: left; display: inline-block; width: auto; min-height: auto;">_x000D_
 <span class="back debug_green"></span>_x000D_
 <span class="cont debug_red">_x000D_
  Pane content.<br/>_x000D_
  Pane content._x000D_

And here's a live demo of the technique being used extensively: screenshot

Append values to query string

Note you can add the Microsoft.AspNetCore.WebUtilities nuget package from Microsoft and then use this to append values to query string:

QueryHelpers.AddQueryString(longurl, "action", "login1")
QueryHelpers.AddQueryString(longurl, new Dictionary<string, string> { { "action", "login1" }, { "attempts", "11" } });

Proper way to handle multiple forms on one page in Django


class AddProductView(generic.TemplateView):
template_name = 'manager/add_product.html'

    def get(self, request, *args, **kwargs):
    form = ProductForm(self.request.GET or None, prefix="sch")
    sub_form = ImageForm(self.request.GET or None, prefix="loc")
    context = super(AddProductView, self).get_context_data(**kwargs)
    context['form'] = form
    context['sub_form'] = sub_form
    return self.render_to_response(context)

def post(self, request, *args, **kwargs):
    form = ProductForm(request.POST,  prefix="sch")
    sub_form = ImageForm(request.POST, prefix="loc")


{% block container %}
<div class="container">
    <form action="{% url 'manager:add_product' %}" method="post">
        {% csrf_token %}
        {{ form.as_p }}
        {{ sub_form.as_p }}
            <button type="submit">Submit</button>
{% endblock %}

Javascript how to split newline

The problem is that when you initialize ks, the value hasn't been set.

You need to fetch the value when user submits the form. So you need to initialize the ks inside the callback function

      //Here it will fetch the value of #keywords
         var ks = $('#keywords').val().split("\n");

How to open a workbook specifying its path

You can also open a required file through a prompt, This helps when you want to select file from different path and different file.

Sub openwb()
Dim wkbk As Workbook
Dim NewFile As Variant

NewFile = Application.GetOpenFilename("microsoft excel files (*.xlsm*), *.xlsm*")

If NewFile <> False Then
Set wkbk = Workbooks.Open(NewFile)
End If
End Sub

Editing in the Chrome debugger

here's a gentle introduction to the js debugger in chrome that i wrote. Maybe it will help others looking for info on this:

Combine two pandas Data Frames (join on a common column)

You can use merge to combine two dataframes into one:

import pandas as pd
pd.merge(restaurant_ids_dataframe, restaurant_review_frame, on='business_id', how='outer')

where on specifies field name that exists in both dataframes to join on, and how defines whether its inner/outer/left/right join, with outer using 'union of keys from both frames (SQL: full outer join).' Since you have 'star' column in both dataframes, this by default will create two columns star_x and star_y in the combined dataframe. As @DanAllan mentioned for the join method, you can modify the suffixes for merge by passing it as a kwarg. Default is suffixes=('_x', '_y'). if you wanted to do something like star_restaurant_id and star_restaurant_review, you can do:

 pd.merge(restaurant_ids_dataframe, restaurant_review_frame, on='business_id', how='outer', suffixes=('_restaurant_id', '_restaurant_review'))

The parameters are explained in detail in this link.

How to manage Angular2 "expression has changed after it was checked" exception when a component property depends on current datetime

I got that error because I declared a variable and later wanted to
changed it's value using ngAfterViewInit

export class SomeComponent {

    header: string;


to fix that I switched from

ngAfterViewInit() { 

    // change variable value here...


ngAfterContentInit() {

    // change variable value here...

Turn a number into star rating display using jQuery and CSS

using jquery without prototype, update the js code to

$( ".stars" ).each(function() { 
    // Get the value
    var val = $(this).data("rating");
    // Make sure that the value is in 0 - 5 range, multiply to get width
    var size = Math.max(0, (Math.min(5, val))) * 16;
    // Create stars holder
    var $span = $('<span />').width(size);
    // Replace the numerical value with stars

I also added a data attribute by the name of data-rating in the span.

<span class="stars" data-rating="4" ></span>

Angular 2 - Checking for server errors from subscribe

As stated in the relevant RxJS documentation, the .subscribe() method can take a third argument that is called on completion if there are no errors.

For reference:

  1. [onNext] (Function): Function to invoke for each element in the observable sequence.
  2. [onError] (Function): Function to invoke upon exceptional termination of the observable sequence.
  3. [onCompleted] (Function): Function to invoke upon graceful termination of the observable sequence.

Therefore you can handle your routing logic in the onCompleted callback since it will be called upon graceful termination (which implies that there won't be any errors when it is called).

      result => {
        // Handle result
      error => {
        this.errors = error;
      () => {
        // 'onCompleted' callback.
        // No errors, route to new page here

As a side note, there is also a .finally() method which is called on completion regardless of the success/failure of the call. This may be helpful in scenarios where you always want to execute certain logic after an HTTP request regardless of the result (i.e., for logging purposes or for some UI interaction such as showing a modal).


Invokes a specified action after the source observable sequence terminates gracefully or exceptionally.

For instance, here is a basic example:

import { Observable } from 'rxjs/Rx';
import 'rxjs/add/operator/finally';

// ...

    .finally(() => {
      // Execute after graceful or exceptionally termination
      console.log('Handle logging logic...');
    .subscribe (
      result => {
        // Handle result
      error => {
        this.errors = error;
      () => {
        // No errors, route to new page

How can I remove duplicate rows?

CREATE TABLE car(Id int identity(1,1), PersonId int, CarId int)

INSERT INTO car(PersonId,CarId)


SELECT ROW_NUMBER() over (PARTITION BY personid,carid order by personid,carid) as rn,Id,PersonID,CarId from car)


How to use the divide function in the query?

Assuming all of these columns are int, then the first thing to sort out is converting one or more of them to a better data type - int division performs truncation, so anything less than 100% would give you a result of 0:


Here, I've mutiplied one of the numbers by 100.0 which will force the result of the calculation to be done with floats rather than ints. By choosing 100, I'm also getting it ready to be treated as a %.

I was also a little confused by your bracketing - I think I've got it correct - but you had brackets around single values, and then in other places you had a mix of operators (- and /) at the same level, and so were relying on the precedence rules to define which operator applied first.

Performing a Stress Test on Web Application?

Try ZebraTester which is much easier to use than jMeter. I have used jMeter for a long time but the total setup time for a load test was always an issue. Although ZebraTester isn't open source, the time that I have saved in the last six months makes up for it. They also have a SaaS portal which can be used for quickly running tests using their load generators.

C# Lambda expressions: Why should I use them?

A lambda expression is like an anonymous method written in place of a delegate instance.

delegate int MyDelagate (int i);
MyDelagate delSquareFunction = x => x * x;

Consider the lambda expression x => x * x;

The input parameter value is x (on the left side of =>)

The function logic is x * x (on the right side of =>)

A lambda expression's code can be a statement block instead of an expression.

x => {return x * x;};


Note: Func is a predefined generic delegate.

    Console.WriteLine(MyMethod(x => "Hi " + x));

    public static string MyMethod(Func<string, string> strategy)
        return strategy("Lijo").ToString();


  1. How can a delegate & interface be used interchangeably?

How do I create a file at a specific path?

f = open("", "a") Will be created in whatever directory the python file is run from.

I'm not sure about the other error...I don't work in windows.

How to listen for 'props' changes

@JoeSchr has an answer. Here is another way to do if you don't want deep: true

 mounted() {
    // re-render any time a prop changes
    Object.keys(this.$options.props).forEach(key => {
      this.$watch(key, this.yourMethod);

How to get numeric position of alphabets in java?

String word = "blah blah";

for(int i =0;i<word.length;++i)

System.out.print((int)word.charAt(i) - (int)'a'+1);
System.out.print((int)word.charAt(i)-(int)'A' +1);

Wait on the Database Engine recovery handle failed. Check the SQL server error log for potential causes

In my case, setting SQL Server Database Engine service startup account to NT AUTHORITY\NETWORK SERVICE failed, but setting it to NT Authority\System allowed me to succesfully install my SQL Server 2016 STD instance.

Just check the following snapshot.

enter image description here

For further details, check @Shanky's answer at

Remember: you can avoid server rebooting using setup's SkipRules switch:

setup.exe /ACTION=INSTALL /SkipRules=RebootRequiredCheck

setup.exe /ACTION=UNINSTALL /SkipRules=RebootRequiredCheck

Angular ng-click with call to a controller function not working

You should probably use the ngHref directive along with the ngClick:

 <a ng-href='#here' ng-click='go()' >click me</a>

Here is an example:

<body ng-controller="MainCtrl">
    <p>Hello {{name}}!</p>
    <a ng-href='#here' ng-click='go()' >click me</a>
    <div style='height:1000px'>

      <a id='here'></a>


var app = angular.module('plunker', []);

app.controller('MainCtrl', function($scope) {
  $ = 'World';

  $scope.go = function() {

    $scope.msg = 'clicked';

I don't know if this will work with the library you are using but it will at least let you link and use the ngClick function.

** Update **

Here is a demo of the set and get working fine with a service.

var app = angular.module('plunker', []);

app.controller('MainCtrl', function($scope, sharedProperties) {
  $ = 'World';

  $scope.go = function(item) {


  $scope.getItem = function() {

    $scope.msg = sharedProperties.getListName();

app.service('sharedProperties', function () {
    var list_name = '';

    return {

        getListName: function() {
            return list_name;
        setListName: function(name) {
            list_name = name;


* Edit *

Please review which talks about how to use lungo and angular. Also note that if your page is completely reloading when browsing to another link, you will need to persist your shared properties into localstorage and/or a cookie.

Search in all files in a project in Sublime Text 3

You can put <project> in "Where:" box to search from the current Sublime project from the Find in Files menu.

This is more useful than searching from the root folder for when your project is including or excluding particular folders or file extensions.

Handle ModelState Validation in ASP.NET Web API

Here you can check to show the model state error one by one

 public HttpResponseMessage CertificateUpload(employeeModel emp)
        if (!ModelState.IsValid)
            string errordetails = "";
            var errors = new List<string>();
            foreach (var state in ModelState)
                foreach (var error in state.Value.Errors)
                    string p = error.ErrorMessage;
                    errordetails = errordetails + error.ErrorMessage;

            Dictionary<string, object> dict = new Dictionary<string, object>();

            dict.Add("error", errordetails);
            return Request.CreateResponse(HttpStatusCode.BadRequest, dict);

      //do something


Setting Access-Control-Allow-Origin in ASP.Net MVC - simplest possible method

WebAPI 2 now has a package for CORS which can be installed using : Install-Package Microsoft.AspNet.WebApi.Cors -pre -project WebServic

Once this is installed, follow this for the code :