Programs & Examples On #Failed to load viewstate

The failed to load viewstate error is a frequent problem encountered when creating dynamic pages when you fail to create the controls exactly the same way each postback.

How to get a List<string> collection of values from app.config in WPF?

Thank for the question. But I have found my own solution to this problem. At first, I created a method

    public T GetSettingsWithDictionary<T>() where T:new()
        IConfigurationRoot _configurationRoot = new ConfigurationBuilder()
        .AddXmlFile($"{Assembly.GetExecutingAssembly().Location}.config", false, true).Build();

        var instance = new T();
        foreach (var property in typeof(T).GetProperties())
            if (property.PropertyType == typeof(Dictionary<string, string>))
                property.SetValue(instance, _configurationRoot.GetSection(typeof(T).Name).Get<Dictionary<string, string>>());

        return instance;

Then I used this method to produce an instance of a class

var connStrs = GetSettingsWithDictionary<AuthMongoConnectionStrings>();

I have the next declaration of class

public class AuthMongoConnectionStrings
    public Dictionary<string, string> ConnectionStrings { get; set; }

and I store my setting in App.config

  Third="33" />

How can I read pdf in python?

You can USE PyPDF2 package

#install pyDF2
pip install PyPDF2

# importing all the required modules
import PyPDF2

# creating an object 
file = open('example.pdf', 'rb')

# creating a pdf reader object
fileReader = PyPDF2.PdfFileReader(file)

# print the number of pages in pdf file

Follow this Documentation

What is the SSIS package and what does it do?

SSIS (SQL Server Integration Services) is an upgrade of DTS (Data Transformation Services), which is a feature of the previous version of SQL Server. SSIS packages can be created in BIDS (Business Intelligence Development Studio). These can be used to merge data from heterogeneous data sources into SQL Server. They can also be used to populate data warehouses, to clean and standardize data, and to automate administrative tasks.

SQL Server Integration Services (SSIS) is a component of Microsoft SQL Server 2005. It replaces Data Transformation Services, which has been a feature of SQL Server since Version 7.0. Unlike DTS, which was included in all versions, SSIS is only available in the "Standard" and "Enterprise" editions. Integration Services provides a platform to build data integration and workflow applications. The primary use for SSIS is data warehousing as the product features a fast and flexible tool for data extraction, transformation, and loading (ETL).). The tool may also be used to automate maintenance of SQL Server databases, update multidimensional cube data, and perform other functions.

Which command do I use to generate the build of a Vue app?

if you used vue-cli and webpack when you created your project.

you can use just

npm run build command in command line, and it will create dist folder in your project. Just upload content of this folder to your ftp and done.

Clear text in EditText when entered

If the use of EditText is not mandatory, you can implement this behavior easily with the new material components:


                android:text="@{itemModel.value}" />


You only have to specify the drawable you want for the button that will clear the text and the action that it will execute. To clear the text, you can use iconMode="clear_text", but also "password_toggle" is available.

Google Map API v3 — set bounds and center

Use below one,

map.setCenter(bounds.getCenter(), map.getBoundsZoomLevel(bounds));

Rails: Default sort order for a rails model?


This works for Rails 4+:

class Book < ActiveRecord::Base
  default_scope { order(created_at: :desc) }

For Rails 2.3, 3, you need this instead:

default_scope order('created_at DESC')

For Rails 2.x:

default_scope :order => 'created_at DESC'

Where created_at is the field you want the default sorting to be done on.

Note: ASC is the code to use for Ascending and DESC is for descending (desc, NOT dsc !).


Once you're used to that you can also use scope:

class Book < ActiveRecord::Base
  scope :confirmed, :conditions => { :confirmed => true }
  scope :published, :conditions => { :published => true }

For Rails 2 you need named_scope.

:published scope gives you Book.published instead of Book.find(:published => true).

Since Rails 3 you can 'chain' those methods together by concatenating them with periods between them, so with the above scopes you can now use Book.published.confirmed.

With this method, the query is not actually executed until actual results are needed (lazy evaluation), so 7 scopes could be chained together but only resulting in 1 actual database query, to avoid performance problems from executing 7 separate queries.

You can use a passed in parameter such as a date or a user_id (something that will change at run-time and so will need that 'lazy evaluation', with a lambda, like this:

scope :recent_books, lambda 
  { |since_when| where("created_at >= ?", since_when) }
  # Note the `where` is making use of AREL syntax added in Rails 3.

Finally you can disable default scope with:

Book.with_exclusive_scope { find(:all) } 

or even better:


which will disable any filter (conditions) or sort (order by).

Note that the first version works in Rails2+ whereas the second (unscoped) is only for Rails3+

So ... if you're thinking, hmm, so these are just like methods then..., yup, that's exactly what these scopes are!
They are like having def self.method_name ...code... end but as always with ruby they are nice little syntactical shortcuts (or 'sugar') to make things easier for you!

In fact they are Class level methods as they operate on the 1 set of 'all' records.

Their format is changing however, with rails 4 there are deprecation warning when using #scope without passing a callable object. For example scope :red, where(color: 'red') should be changed to scope :red, -> { where(color: 'red') }.

As a side note, when used incorrectly, default_scope can be misused/abused.
This is mainly about when it gets used for actions like where's limiting (filtering) the default selection (a bad idea for a default) rather than just being used for ordering results.
For where selections, just use the regular named scopes. and add that scope on in the query, e.g. Book.all.published where published is a named scope.

In conclusion, scopes are really great and help you to push things up into the model for a 'fat model thin controller' DRYer approach.

Get index of array element faster than O(n)

Is there a good reason not to use a hash? Lookups are O(1) vs. O(n) for the array.

How to get the mobile number of current sim card in real device?

Sometimes you can retreive the phonenumber with a USSD request to your operator. For example I can get my phonenumber by dialing *116# This can probably be done within an app, I guess, if the USSD responce somehow could be catched. Offcourse this is not a method I would recommend to use within an app that is to be distributed, the code may even differ between operators.

How to get a value inside an ArrayList java

The list may contain several elements, so the get method takes an argument : the index of the element you want to retrieve. If you want the first one, then it's 0.

The list contains Car instances, so you just have to do

Car firstCar = car.get(0);
String price = firstCar.getPrice();

or just

String price = car.get(0).getPrice();

The car variable should be named cars, since it's a list and thus contains several cars.

Read the tutorial about collections. And learn to use the javadoc: all the classes and methods are documented.

Iterate through a C array

If the size of the array is known at compile time, you can use the structure size to determine the number of elements.

struct foo fooarr[10];

for(i = 0; i < sizeof(fooarr) / sizeof(struct foo); i++)

If it is not known at compile time, you will need to store a size somewhere or create a special terminator value at the end of the array.

Simpler way to create dictionary of separate variables?

Well, I encountered the very same need a few days ago and had to get a variable's name which was pointing to the object itself.

And why was it so necessary?

In short I was building a plug-in for Maya. The core plug-in was built using C++ but the GUI is drawn through Python(as its not processor intensive). Since I, as yet, don't know how to return multiple values from the plug-in except the default MStatus, therefore to update a dictionary in Python I had to pass the the name of the variable, pointing to the object implementing the GUI and which contained the dictionary itself, to the plug-in and then use the MGlobal::executePythonCommand() to update the dictionary from the global scope of Maya.

To do that what I did was something like:

import time

class foo(bar):

    def __init__(self):
        super(foo, self).__init__()
        self.time = time.time() #almost guaranteed to be unique on a single computer

    def name(self):
        g = globals()
        for x in g:
            if isinstance(g[x], type(self)):
                if g[x].time == self.time:
                    return x
                    #or you could:
                    #return filter(None,[x if g[x].time == self.time else None for x in g if isinstance(g[x], type(self))])
                    #and return all keys pointing to object itself

I know that it is not the perfect solution in in the globals many keys could be pointing to the same object e.g.:

a = foo()
b = a

and that the approach isn't thread-safe. Correct me if I am wrong.

At least this approach solved my problem by getting the name of any variable in the global scope which pointed to the object itself and pass it over to the plug-in, as argument, for it use internally.

I tried this on int (the primitive integer class) but the problem is that these primitive classes don't get bypassed (please correct the technical terminology used if its wrong). You could re-implement int and then do int = foo but a = 3 will never be an object of foo but of the primitive. To overcome that you have to a = foo(3) to get to work.

Detect backspace and del on "input" event?

It's an old question, but if you wanted to catch a backspace event on input, and not keydown, keypress, or keyup—as I've noticed any one of these break certain functions I've written and cause awkward delays with automated text formatting—you can catch a backspace using inputType:

document.getElementsByTagName('input')[0].addEventListener('input', function(e) {
    if (e.inputType == "deleteContentBackward") {
        // your code here

Create a Bitmap/Drawable from file path

Well, using the static Drawable.createFromPath(String pathName) seems a bit more straightforward to me than decoding it yourself... :-)

If your mImg is a simple ImageView, you don't even need it, use mImg.setImageUri(Uri uri) directly.

What exactly does an #if 0 ..... #endif block do?

Not quite

int main(void)
   #if 0
     the apostrophe ' causes a warning
   return 0;

It shows "t.c:4:19: warning: missing terminating ' character" with gcc 4.2.4

How to specify an alternate location for the .m2 folder or settings.xml permanently?

Below is the configuration in Maven software by default in MAVEN_HOME\conf\settings.xml.

  <!-- localRepository
   | The path to the local repository maven will use to store artifacts.
   | Default: ~/.m2/repository

Add the below line under this configuration, will fulfill the requirement.


Ex: <localRepository>D:/MYNAME/settings/.m2/repository</localRepository>

Best way to serialize/unserialize objects in JavaScript?

JSON has no functions as data types. You can only serialize strings, numbers, objects, arrays, and booleans (and null)

You could create your own toJson method, only passing the data that really has to be serialized:

Person.prototype.toJson = function() {
    return JSON.stringify({age: this.age});

Similar for deserializing:

Person.fromJson = function(json) {
    var data = JSON.parse(json); // Parsing the json string.
    return new Person(data.age);

The usage would be:

var serialize = p1.toJson();
var _p1 = Person.fromJson(serialize);
alert("Is old: " + _p1.isOld());

To reduce the amount of work, you could consider to store all the data that needs to be serialized in a special "data" property for each Person instance. For example:

function Person(age) { = {
        age: age
    this.isOld = function (){
        return > 60 ? true : false;

then serializing and deserializing is merely calling JSON.stringify( and setting the data of an instance would be = JSON.parse(json).

This would keep the toJson and fromJson methods simple but you'd have to adjust your other functions.

Side note:

You should add the isOld method to the prototype of the function:

Person.prototype.isOld = function() {}

Otherwise, every instance has it's own instance of that function which also increases memory.

What is the most effective way for float and double comparison?

The portable way to get epsilon in C++ is

#include <limits>

Then the comparison function becomes

#include <cmath>
#include <limits>

bool AreSame(double a, double b) {
    return std::fabs(a - b) < std::numeric_limits<double>::epsilon();

A valid provisioning profile for this executable was not found for debug mode

Had the same problem. My solution was very easy. I checked If I have my device's UDID in and it was absent. After I added it, it starts working. It is very annoying that Apple developers give error "A valid provisioning profile for this executable was not found" instead of "UDID is not found". Actually I mentioned it first in XCode 6...

How do I convert a string to enum in TypeScript?

Enums in TypeScript 0.9 are string+number based. You should not need type assertion for simple conversions:

enum Color{
    Red, Green

// To String
 var green: string = Color[Color.Green];

// To Enum / number
var color : Color = Color[green];

Try it online

I have documention about this and other Enum patterns in my OSS book :

Case insensitive regular expression without re.compile?

You can also define case insensitive during the pattern compile:

pattern = re.compile('FIle:/+(.*)', re.IGNORECASE)

What is for Python what 'explode' is for PHP?

The alternative for explode in php is split.

The first parameter is the delimiter, the second parameter the maximum number splits. The parts are returned without the delimiter present (except possibly the last part). When the delimiter is None, all whitespace is matched. This is the default.

>>> "Rajasekar SP".split()
['Rajasekar', 'SP']

>>> "Rajasekar SP".split('a',2)
['R','j','sekar SP']

jQuery ID starts with


$("td[id^=" + value + "]")

how to get yesterday's date in C#

var yesterday = DateTime.Now.AddDays(-1);

Invalid postback or callback argument. Event validation is enabled using '<pages enableEventValidation="true"/>'

In this case add id to the button in RowDataBound of the grid. It will solve your problem.

Print time in a batch file (milliseconds)

%TIME% is in the format H:MM:SS,CS after midnight and hence conversion to centiseconds >doesn't work. Seeing Patrick Cuff's post with 6:46am it seems that it is not only me.

But with this lines bevor you should will fix that problem easy:

if " "=="%StartZeit:~0,1%" set StartZeit=0%StartZeit:~-10%
if " "=="%EndZeit:~0,1%" set EndZeit=0%EndZeit:~-10%

Thanks for your nice inspiration! I like to use it in my mplayer, ffmpeg, sox Scripts to pimp my mediafiles for old PocketPlayers just for fun.

How to check if an object is defined?

If a class type is not defined, you'll get a compiler error if you try to use the class, so in that sense you should have to check.

If you have an instance, and you want to ensure it's not null, simply check for null:

if (value != null)
    // it's not null. 

Ascii/Hex convert in bash

for letter in $(echo "$Text2Conv" | sed "s/\(.\)/'\1 /g");do printf '%x' "$letter";done


The trick is using sed to parse the Text2Conv to format we can then seperate anf loop using for.

ASP.NET Core configuration for .NET Core console application

On .Net Core 3.1 we just need to do these:

static void Main(string[] args)
  var configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();

Using SeriLog will look like:

using Microsoft.Extensions.Configuration;
using Serilog;
using System;

namespace yournamespace
    class Program

        static void Main(string[] args)
            var configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();
            Log.Logger = new LoggerConfiguration().ReadFrom.Configuration(configuration).CreateLogger();

                Log.Information("Starting Program.");
            catch (Exception ex)
                Log.Fatal(ex, "Program terminated unexpectedly.");

And the Serilog appsetings.json section for generating one file daily will look like:

  "Serilog": {
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft": "Warning",
        "System": "Warning"
    "Using": [ "Serilog.Sinks.Console", "Serilog.Sinks.File" ],
    "WriteTo": [
        "Name": "File",
        "Args": {
          "path": "C:\\Logs\\Program.json",
          "rollingInterval": "Day",
          "formatter": "Serilog.Formatting.Compact.CompactJsonFormatter, Serilog.Formatting.Compact"

How does collections.defaultdict work?

Usually, a Python dictionary throws a KeyError if you try to get an item with a key that is not currently in the dictionary. The defaultdict in contrast will simply create any items that you try to access (provided of course they do not exist yet). To create such a "default" item, it calls the function object that you pass to the constructor (more precisely, it's an arbitrary "callable" object, which includes function and type objects). For the first example, default items are created using int(), which will return the integer object 0. For the second example, default items are created using list(), which returns a new empty list object.

create table with sequence.nextval in oracle

In Oracle 12c, you can now specify the CURRVAL and NEXTVAL sequence pseudocolumns as default values for a column. Alternatively, you can use Identity columns; see:


  id          NUMBER DEFAULT t1_seq.NEXTVAL,
  description VARCHAR2(30)

Proper way to exit command line program?

if you do ctrl-z and then type exit it will close background applications.

Ctrl+Q is another good way to kill the application.

Mongoose (mongodb) batch insert?

Mongoose 4.4.0 now supports bulk insert

Mongoose 4.4.0 introduces --true-- bulk insert with the model method .insertMany(). It is way faster than looping on .create() or providing it with an array.


var rawDocuments = [/* ... */];

    .then(function(mongooseDocuments) {
         /* ... */
    .catch(function(err) {
        /* Error handling */


Book.insertMany(rawDocuments, function (err, mongooseDocuments) { /* Your callback function... */ });

You can track it on:

Android Eclipse - Could not find *.apk

I tried all the above solutions. but it didn't work.

The solution was to restart eclipse !!!!!!!

hope this will help someone :)

Android studio, gradle and NDK

While I believe SJoshi (oracle guy) has the most complete answer, the SWIG project is a special case, interesting and useful one, at that, but not generalized for the majority of projects that have done well with the standard SDK ant based projects + NDK. We all would like to be using Android studio now most likely, or want a more CI friendly build toolchain for mobile, which gradle theoretically offers.

I've posted my approach, borrowed from somewhere (I found this on SO, but posted a gist for the app build.gradle: ). In a nutshell, I recommend the following:

  • Don't upgrade your project to the latest gradle build
  • Use in your Project root
  • Use in your app project
  • Make sure has: android.useDeprecatedNdk=true (in case it's complaining)
  • Use the above approach to ensure that your hours and hours of effort creating files won't be tossed away. You control which targets arch(s) to build. And these instructions are kind to Windows users, who should theoretically be able to build on windows without special issues.

Gradle for Android has been a mess in my opinion, much as I like the maven concepts borrowed and the opinionated structure of directories for a project. This NDK feature has been "coming soon" for almost 3+ years.

C# removing items from listbox

You can't modify the references in an enumerator whilst you enumerate over it; you must keep track of the ones to remove then remove them.

This is an example of the work around:

List<string> listbox = new List<string>();
List<object> toRemove = new List<object>();

foreach (string item in listbox)
    string removelistitem = "OBJECT";
    if (item.Contains(removelistitem))

foreach (string item in toRemove)

But if you're using c#3.5, you could say something like this.

listbox.Items = listbox.Items.Select(n => !n.Contains("OBJECT"));

Postgres "psql not recognized as an internal or external command"

Simple solution that hasn't been mentioned on this question: restart your computer after you declare the path variable.

I always have to restart - the path never updates until I do. And when I do restart, the path always is updated.

How to change default JRE for all Eclipse workspaces?

try to change the order: right click on you project-> BuildPath->Configure...->Order and Export tab -> move jre7 UP.

How to make return key on iPhone make keyboard disappear?

After quite a bit of time hunting down something that makes sense, this is what I put together and it worked like a charm.


//  ViewController.h
//  demoKeyboardScrolling
//  Created by Chris Cantley on 11/14/13.
//  Copyright (c) 2013 Chris Cantley. All rights reserved.

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <UITextFieldDelegate>

// Connect your text field to this the below property.
@property (weak, nonatomic) IBOutlet UITextField *theTextField;



//  ViewController.m
//  demoKeyboardScrolling
//  Created by Chris Cantley on 11/14/13.
//  Copyright (c) 2013 Chris Cantley. All rights reserved.

#import "ViewController.h"

@interface ViewController ()


@implementation ViewController

- (void)viewDidLoad
    [super viewDidLoad];
    // _theTextField is the name of the parameter designated in the .h file. 
    _theTextField.returnKeyType = UIReturnKeyDone;
    [_theTextField setDelegate:self];


// This part is more dynamic as it closes the keyboard regardless of what text field 
// is being used when pressing return.  
// You might want to control every single text field separately but that isn't 
// what this code do.
-(void)textFieldShouldReturn:(UITextField *)textField
    [textField resignFirstResponder];


Hope this helps!

Razor View Without Layout

You (and KMulligan) are misunderstanding _ViewStart pages.

_ViewStart will always execute, before your page starts.
It is intended to be used to initialize properties (such as Layout); it generally should not contain markup. (Since there is no way to override it).

The correct pattern is to make a separate layout page which calls RenderBody, and set the Layout property to point to this page in _ViewStart.

You can then change Layout in your content pages, and the changes will take effect.

How can I know when an EditText loses focus?

Have your Activity implement OnFocusChangeListener() if you want a factorized use of this interface, example:

public class Shops extends AppCompatActivity implements View.OnFocusChangeListener{

In your OnCreate you can add a listener for example:


then android studio will prompt you to add the method from the interface, accept it... it will be like:

public void onFocusChange(View v, boolean hasFocus) {
// todo your code here...

and as you've got a factorized code, you'll just have to do that:

public void onFocusChange(View v, boolean hasFocus) {
   if (hasFocus) {
    if (!hasFocus){
        editTextMyWords.setText(" One Two Tree!");
        editTextPhone.setText("\"your phone here:\"");

anything you code in the !hasFocus is for the behavior of the item that loses focus, that should do the trick! But beware that in such state, the change of focus might overwrite the user's entries!

JavaScript inside an <img title="<a href='#' onClick='alert('Hello World!')>The Link</a>" /> possible?

Im my browser, this doesn't work at all. The tooltip field doesn't show a link, but <a href='#' onClick='alert('Hello World!')>The Link</a>. I'm using FF 3.6.12.

You'll have to do this by hand with JS and CSS. Begin here

Finding longest string in array

In case you expect more than one maximum this will work:

_.maxBy(Object.entries(_.groupBy(x, y => y.length)), y => parseInt(y[0]))[1]

It uses lodash and returns an array.

Simulating a click in jQuery/JavaScript on a link

Why not just the good ol' javascript?


xcode-select active developer directory error

I had to run this first

sudo xcode-select --reset


sudo xcode-select -switch /Library/Developer/CommandLineTools

and then it worked.

What is the difference between "Form Controls" and "ActiveX Control" in Excel 2010?

Google is full of information on this. As Hans Passant said, Form controls are built in to Excel whereas ActiveX controls are loaded separately.

Generally you'll use Forms controls, they're simpler. ActiveX controls allow for more flexible design and should be used when the job just can't be done with a basic Forms control.

Many user's computers by default won't trust ActiveX, and it will be disabled; this sometimes needs to be manually added to the trust center. ActiveX is a microsoft-based technology and, as far as I'm aware, is not supported on the Mac. This is something you'll have to also consider, should you (or anyone you provide a workbook to) decide to use it on a Mac.

Find files in created between a date range

Some good solutions on here. Wanted to share mine as well as it is short and simple.

I'm using find (GNU findutils) 4.5.11

$ find search/path/ -newermt 20130801 \! -newermt 20130831

Javascript Drag and drop for touch devices

Thanks for the above codes! - I tried several options and this was the ticket. I had problems in that preventDefault was preventing scrolling on the ipad - I am now testing for draggable items and it works great so far.

if ( == 'draggable_item' ) {

How to use PHP to connect to sql server

MS SQL connect to php

  1. Install the drive from microsoft link

  2. After install you will get some files. Store it in your system temp folder

  3. Check your php version , thread or non thread , and window bit - 32 or 64 (Thread or non thread , this is get you by phpinfo() )

  4. According to your system & xampp configration (php version and all ) copy 2 files (php_sqlsrv & php_pdo_sqlsrv) to xampp/php/ext folder .

  5. Add to php.ini file extension=php_sqlsrv_72_ts_x64 (php_sqlsrv_72_ts_x64.dll is your file which your copy in 4th step ) extension=php_pdo_sqlsrv_72_ts_x64 (php_pdo_sqlsrv_72_ts_x64.dll is your file which your copy in 4th step )

  6. Next Php Code

    $serverName ="DESKTOP-me\MSSQLSERVER01"; (servername\instanceName)

    // Since UID and PWD are not specified in the $connectionInfo array, // The connection will be attempted using Windows Authentication.

    $connectionInfo = array("Database"=>"testdb","CharacterSet"=>"UTF-8");

    $conn = sqlsrv_connect( $serverName, $connectionInfo);

    if( $conn ) { //echo "Connection established.
    "; }else{ echo "Connection could not be established.
    "; die( print_r( sqlsrv_errors(), true)); }

    //$sql = "INSERT INTO dbo.master ('name') VALUES ('test')"; $sql = "SELECT * FROM dbo.master"; $stmt = sqlsrv_query( $conn, $sql );

    while( $row = sqlsrv_fetch_array( $stmt, SQLSRV_FETCH_ASSOC) ) { echo $row['id'].", ".$row['name']."
    "; }

    sqlsrv_free_stmt( $stmt);


Joins can only be used when there is an association between entities. Your Employee entity should not have a field named id_team, of type int, mapped to a column. It should have a ManyToOne association with the Team entity, mapped as a JoinColumn:

private Team team;

Then, the following query will work flawlessly:

select e from Employee e inner join

Which will load all the employees, except those that aren't associated to any team.

The same goes for all the other fields which are a foreign key to some other table mapped as an entity, of course (id_boss, id_profession).

It's time for you to read the Hibernate documentation, because you missed an extremely important part of what it is and how it works.

Use of symbols '@', '&', '=' and '>' in custom directive's scope binding: AngularJS

In an AngularJS directive the scope allows you to access the data in the attributes of the element to which the directive is applied.

This is illustrated best with an example:

<div my-customer name="Customer XYZ"></div>

and the directive definition:

angular.module('myModule', [])
.directive('myCustomer', function() {
  return {
    restrict: 'E',
    scope: {
      customerName: '@name'
    controllerAs: 'vm',
    bindToController: true,
    controller: ['$http', function($http) {
      var vm = this;

      vm.doStuff = function(pane) {
    link: function(scope, element, attrs) {

When the scope property is used the directive is in the so called "isolated scope" mode, meaning it can not directly access the scope of the parent controller.

In very simple terms, the meaning of the binding symbols is:

someObject: '=' (two-way data binding)

someString: '@' (passed directly or through interpolation with double curly braces notation {{}})

someExpression: '&' (e.g. hideDialog())

This information is present in the AngularJS directive documentation page, although somewhat spread throughout the page.

The symbol > is not part of the syntax.

However, < does exist as part of the AngularJS component bindings and means one way binding.

How to write a stored procedure using phpmyadmin and how to use it through php?

  1. delimiter ;;
  2. CREATE PROCEDURE sp_number_example_records()
  3. BEGIN
    SELECT count(id) from customer; END
  4. ;;

round() for float in C++

Boost offers a simple set of rounding functions.

#include <boost/math/special_functions/round.hpp>

double a = boost::math::round(1.5); // Yields 2.0
int b = boost::math::iround(1.5); // Yields 2 as an integer

For more information, see the Boost documentation.

Edit: Since C++11, there are std::round, std::lround, and std::llround.

findAll() in yii

$id = 101;

$sql = 'SELECT * FROM ur_tbl t WHERE t.email_id = '. $id;
$email = Yii::app()->db->createCommand($sql)->queryAll();


How can I check for an empty/undefined/null string in JavaScript?


if (str && str.trim().length) {  

How do I read and parse an XML file in C#?

You could use a DataSet to read XML strings.

var xmlString = File.ReadAllText(FILE_PATH);
var stringReader = new StringReader(xmlString);
var dsSet = new DataSet();

Posting this for the sake of information.

Show/hide widgets in Flutter programmatically

Flutter now contains a Visibility Widget that you should use to show/hide widgets. The widget can also be used to switch between 2 widgets by changing the replacement.

This widget can achieve any of the states visible, invisible, gone and a lot more.

      visible: true //Default is true,
      child: Text('Ndini uya uya'),
      //maintainSize: bool. When true this is equivalent to invisible;
      //replacement: Widget. Defaults to Sizedbox.shrink, 0x0

How to append a char to a std::string?

I found a simple way... I needed to tack a char on to a string that was being built on the fly. I needed a char list; because I was giving the user a choice and using that choice in a switch() statement.

I simply added another std::string Slist; and set the new string equal to the character, "list" - a, b, c or whatever the end user chooses like this:

char list;
std::string cmd, state[], Slist;
Slist = list; //set this string to the chosen char;
cmd = Slist + state[x] + "whatever";

Complexity may be cool but simplicity is cooler. IMHO

MYSQL order by both Ascending and Descending sorting

I don't understand what the meaning of ordering with the same column ASC and DESC in the same ORDER BY, but this how you can do it: naam DESC, naam ASC like so:

ORDER BY `product_category_id` DESC,`naam` DESC, `naam` ASC

Getting the object's property name

As of 2018 , You can make use of Object.getOwnPropertyNames() as described in Developer Mozilla Documentation

const object1 = {
  a: 1,
  b: 2,
  c: 3

// expected output: Array ["a", "b", "c"]

jQuery append() vs appendChild()

No longer

now append is a method in JavaScript

MDN documentation on append method

Quoting MDN

The ParentNode.append method inserts a set of Node objects or DOMString objects after the last child of the ParentNode. DOMString objects are inserted as equivalent Text nodes.

This is not supported by IE and Edge but supported by Chrome(54+), Firefox(49+) and Opera(39+).

The JavaScript's append is similar to jQuery's append.

You can pass multiple arguments.

var elm = document.getElementById('div1');
<div id="div1"></div>

Why do we need boxing and unboxing in C#?


To have a unified type system and allow value types to have a completely different representation of their underlying data from the way that reference types represent their underlying data (e.g., an int is just a bucket of thirty-two bits which is completely different than a reference type).

Think of it like this. You have a variable o of type object. And now you have an int and you want to put it into o. o is a reference to something somewhere, and the int is emphatically not a reference to something somewhere (after all, it's just a number). So, what you do is this: you make a new object that can store the int and then you assign a reference to that object to o. We call this process "boxing."

So, if you don't care about having a unified type system (i.e., reference types and value types have very different representations and you don't want a common way to "represent" the two) then you don't need boxing. If you don't care about having int represent their underlying value (i.e., instead have int be reference types too and just store a reference to their underlying value) then you don't need boxing.

where should I use it.

For example, the old collection type ArrayList only eats objects. That is, it only stores references to somethings that live somewhere. Without boxing you cannot put an int into such a collection. But with boxing, you can.

Now, in the days of generics you don't really need this and can generally go merrily along without thinking about the issue. But there are a few caveats to be aware of:

This is correct:

double e = 2.718281828459045;
int ee = (int)e;

This is not:

double e = 2.718281828459045;
object o = e; // box
int ee = (int)o; // runtime exception

Instead you must do this:

double e = 2.718281828459045;
object o = e; // box
int ee = (int)(double)o;

First we have to explicitly unbox the double ((double)o) and then cast that to an int.

What is the result of the following:

double e = 2.718281828459045;
double d = e;
object o1 = d;
object o2 = e;
Console.WriteLine(d == e);
Console.WriteLine(o1 == o2);

Think about it for a second before going on to the next sentence.

If you said True and False great! Wait, what? That's because == on reference types uses reference-equality which checks if the references are equal, not if the underlying values are equal. This is a dangerously easy mistake to make. Perhaps even more subtle

double e = 2.718281828459045;
object o1 = e;
object o2 = e;
Console.WriteLine(o1 == o2);

will also print False!

Better to say:


which will then, thankfully, print True.

One last subtlety:

[struct|class] Point {
    public int x, y;

    public Point(int x, int y) {
        this.x = x;
        this.y = y;

Point p = new Point(1, 1);
object o = p;
p.x = 2;

What is the output? It depends! If Point is a struct then the output is 1 but if Point is a class then the output is 2! A boxing conversion makes a copy of the value being boxed explaining the difference in behavior.

Disabling Warnings generated via _CRT_SECURE_NO_DEPRECATE

Another late answer... Here's how Microsoft uses it in their wchar.h. Notice they also disable Warning C6386:

__inline _CRT_INSECURE_DEPRECATE_MEMORY(wmemcpy_s) wchar_t * __CRTDECL
wmemcpy(_Out_opt_cap_(_N) wchar_t *_S1, _In_opt_count_(_N) const wchar_t *_S2, _In_ size_t _N)
    #pragma warning( push )
    #pragma warning( disable : 4996 6386 )
        return (wchar_t *)memcpy(_S1, _S2, _N*sizeof(wchar_t));
    #pragma warning( pop )

C# DateTime to "YYYYMMDDHHMMSS" format

It is not a big deal. you can simply put like this


Excuse here for I used $ which is for string Interpolation .

LINQ equivalent of foreach for IEnumerable<T>

ForEach can also be Chained, just put back to the pileline after the action. remain fluent


Orders  //just for demo
    .ForEach(o=> o.EmailBuyer() )
    .ForEach(o=> o.ProcessBilling() )
    .ForEach(o=> o.ProcessShipping());

    .ForEach(e=> {  if(e.Salary<1000) e.Raise(0.10);})
    .ForEach(e=> {  if(e.Age   >70  ) e.Retire();});

An Eager version of implementation.

public static IEnumerable<T> ForEach<T>(this IEnumerable<T> enu, Action<T> action)
    foreach (T item in enu) action(item);
    return enu; // make action Chainable/Fluent

Edit: a Lazy version is using yield return, like this.

public static IEnumerable<T> ForEachLazy<T>(this IEnumerable<T> enu, Action<T> action)
    foreach (var item in enu)
        yield return item;

The Lazy version NEEDs to be materialized, ToList() for example, otherwise, nothing happens. see below great comments from ToolmakerSteve.

IQueryable<Product> query = Products.Where(...);
query.ForEachLazy(t => t.Price = t.Price + 1.00)
    .ToList(); //without this line, below SubmitChanges() does nothing.

I keep both ForEach() and ForEachLazy() in my library.

Angular window resize event

On Angular2 (2.1.0) I use ngZone to capture the screen change event.

Take a look on the example:

import { Component, NgZone } from '@angular/core';//import ngZone library
//capture screen changed inside constructor
constructor(private ngZone: NgZone) {
    window.onresize = (e) =>
    { => {

I hope this help!

Why powershell does not run Angular commands?

open windows powershell, run as administrater and SetExecution policy as Unrestricted then it will work.

Deleting folders in python recursively

Try rmtree() in shutil from the Python standard library

What is the difference between VFAT and FAT32 file systems?

Copied from

What's FAT?

FAT may sound like a strange name for a file system, but it's actually an acronym for File Allocation Table. Introduced in 1981, FAT is ancient in computer terms. Because of its age, most operating systems, including Microsoft Windows NT®, Windows 98, the Macintosh OS, and some versions of UNIX, offer support for FAT.

The FAT file system limits filenames to the 8.3 naming convention, meaning that a filename can have no more than eight characters before the period and no more than three after. Filenames in a FAT file system must also begin with a letter or number, and they can't contain spaces. Filenames aren't case sensitive.

What About VFAT?

Perhaps you've also heard of a file system called VFAT. VFAT is an extension of the FAT file system and was introduced with Windows 95. VFAT maintains backward compatibility with FAT but relaxes the rules. For example, VFAT filenames can contain up to 255 characters, spaces, and multiple periods. Although VFAT preserves the case of filenames, it's not considered case sensitive.

When you create a long filename (longer than 8.3) with VFAT, the file system actually creates two different filenames. One is the actual long filename. This name is visible to Windows 95, Windows 98, and Windows NT (4.0 and later). The second filename is called an MS-DOS® alias. An MS-DOS alias is an abbreviated form of the long filename. The file system creates the MS-DOS alias by taking the first six characters of the long filename (not counting spaces), followed by the tilde [~] and a numeric trailer. For example, the filename Brien's Document.txt would have an alias of BRIEN'~1.txt.

An interesting side effect results from the way VFAT stores its long filenames. When you create a long filename with VFAT, it uses one directory entry for the MS-DOS alias and another entry for every 13 characters of the long filename. In theory, a single long filename could occupy up to 21 directory entries. The root directory has a limit of 512 files, but if you were to use the maximum length long filenames in the root directory, you could cut this limit to a mere 24 files. Therefore, you should use long filenames very sparingly in the root directory. Other directories aren't affected by this limit.

You may be wondering why we're discussing VFAT. The reason is it's becoming more common than FAT, but aside from the differences I mentioned above, VFAT has the same limitations. When you tell Windows NT to format a partition as FAT, it actually formats the partition as VFAT. The only time you'll have a true FAT partition under Windows NT 4.0 is when you use another operating system, such as MS-DOS, to format the partition.


FAT32 is actually an extension of FAT and VFAT, first introduced with Windows 95 OEM Service Release 2 (OSR2). FAT32 greatly enhances the VFAT file system but it does have its drawbacks.

The greatest advantage to FAT32 is that it dramatically increases the amount of free hard disk space. To illustrate this point, consider that a FAT partition (also known as a FAT16 partition) allows only a certain number of clusters per partition. Therefore, as your partition size increases, the cluster size must also increase. For example, a 512-MB FAT partition has a cluster size of 8K, while a 2-GB partition has a cluster size of 32K.

This may not sound like a big deal until you consider that the FAT file system only works in single cluster increments. For example, on a 2-GB partition, a 1-byte file will occupy the entire cluster, thereby consuming 32K, or roughly 32,000 times the amount of space that the file should consume. This rule applies to every file on your hard disk, so you can see how much space can be wasted.

Converting a partition to FAT32 reduces the cluster size (and overcomes the 2-GB partition size limit). For partitions 8 GB and smaller, the cluster size is reduced to a mere 4K. As you can imagine, it's not uncommon to gain back hundreds of megabytes by converting a partition to FAT32, especially if the partition contains a lot of small files.

Note: This section of the quote/ article (1999) is out of date. Updated info quote below.

As I mentioned, FAT32 does have limitations. Unfortunately, it isn't compatible with any operating system other than Windows 98 and the OSR2 version of Windows 95. However, Windows 2000 will be able to read FAT32 partitions.

The other disadvantage is that your disk utilities and antivirus software must be FAT32-aware. Otherwise, they could interpret the new file structure as an error and try to correct it, thus destroying data in the process.

Finally, I should mention that converting to FAT32 is a one-way process. Once you've converted to FAT32, you can't convert the partition back to FAT16. Therefore, before converting to FAT32, you need to consider whether the computer will ever be used in a dual-boot environment. I should also point out that although other operating systems such as Windows NT can't directly read a FAT32 partition, they can read it across the network. Therefore, it's no problem to share information stored on a FAT32 partition with other computers on a network that run older operating systems.

Updated mentioned in comment by Doktor-J (assimilated to update out of date answer in case comment is ever lost):

I'd just like to point out that most modern operating systems (WinXP/Vista/7/8, MacOS X, most if not all Linux variants) can read FAT32, contrary to what the second-to-last paragraph suggests.

The original article was written in 1999, and being posted on a Microsoft website, probably wasn't concerned with non-Microsoft operating systems anyways.

The operating systems "excluded" by that paragraph are probably the original Windows 95, Windows NT 4.0, Windows 3.1, DOS, etc.

Save bitmap to location

Create a video thumbnail for a video. It may return null if the video is corrupted or the format is not supported.

private void makeVideoPreview() {
    Bitmap thumbnail = ThumbnailUtils.createVideoThumbnail(videoAbsolutePath, MediaStore.Images.Thumbnails.MINI_KIND);

To Save your bitmap in sdcard use the following code

Store Image

private void storeImage(Bitmap image) {
    File pictureFile = getOutputMediaFile();
    if (pictureFile == null) {
                "Error creating media file, check storage permissions: ");// e.getMessage());
    try {
        FileOutputStream fos = new FileOutputStream(pictureFile);
        image.compress(Bitmap.CompressFormat.PNG, 90, fos);
    } catch (FileNotFoundException e) {
        Log.d(TAG, "File not found: " + e.getMessage());
    } catch (IOException e) {
        Log.d(TAG, "Error accessing file: " + e.getMessage());

To Get the Path for Image Storage

/** Create a File for saving an image or video */
private  File getOutputMediaFile(){
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this. 
    File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
            + "/Android/data/"
            + getApplicationContext().getPackageName()
            + "/Files"); 

    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            return null;
    // Create a media file name
    String timeStamp = new SimpleDateFormat("ddMMyyyy_HHmm").format(new Date());
    File mediaFile;
        String mImageName="MI_"+ timeStamp +".jpg";
        mediaFile = new File(mediaStorageDir.getPath() + File.separator + mImageName);  
    return mediaFile;

Powershell: How can I stop errors from being displayed in a script?

In some cases you can pipe after the command a Out-Null

command | Out-Null

Convert string to Date in java

You are wrong in the way you display the data I guess, because for me:

    String dateString = "03/26/2012 11:49:00 AM";
    SimpleDateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy hh:mm:ss aa");
    Date convertedDate = new Date();
    try {
        convertedDate = dateFormat.parse(dateString);
    } catch (ParseException e) {
        // TODO Auto-generated catch block


Mon Mar 26 11:49:00 EEST 2012

Putting a password to a user in PhpMyAdmin in Wamp

my file in the phpmyadmin folder. Change username and password to the one you have set for your database.

 * This is needed for cookie based authentication to encrypt password in
 * cookie
$cfg['blowfish_secret'] = 'xampp'; /* YOU SHOULD CHANGE THIS FOR A MORE SECURE COOKIE AUTH! */

 * Servers configuration
$i = 0;

 * First server

/* Authentication type and info */
$cfg['Servers'][$i]['auth_type'] = 'config';
$cfg['Servers'][$i]['user'] = 'enter_username_here';
$cfg['Servers'][$i]['password'] = 'enter_password_here';
$cfg['Servers'][$i]['AllowNoPasswordRoot'] = true;

/* User for advanced features */
$cfg['Servers'][$i]['controluser'] = 'pma';
$cfg['Servers'][$i]['controlpass'] = '';

/* Advanced phpMyAdmin features */
$cfg['Servers'][$i]['pmadb'] = 'phpmyadmin';
$cfg['Servers'][$i]['bookmarktable'] = 'pma_bookmark';
$cfg['Servers'][$i]['relation'] = 'pma_relation';
$cfg['Servers'][$i]['table_info'] = 'pma_table_info';
$cfg['Servers'][$i]['table_coords'] = 'pma_table_coords';
$cfg['Servers'][$i]['pdf_pages'] = 'pma_pdf_pages';
$cfg['Servers'][$i]['column_info'] = 'pma_column_info';
$cfg['Servers'][$i]['history'] = 'pma_history';
$cfg['Servers'][$i]['designer_coords'] = 'pma_designer_coords';

 * End of servers configuration


Is there a difference between `continue` and `pass` in a for loop in python?

Difference between pass and continue in a for loop:

So why pass in python?

If you want to create a empty class, method or block.


class MyException(Exception):


without 'pass' in the above examples will throw IndentationError.

What are ODEX files in Android?

This Blog article explains the internals of ODEX files:


In Android file system, applications come in packages with the extension .apk. These application packages, or APKs contain certain .odex files whose supposed function is to save space. These ‘odex’ files are actually collections of parts of an application that are optimized before booting. Doing so speeds up the boot process, as it preloads part of an application. On the other hand, it also makes hacking those applications difficult because a part of the coding has already been extracted to another location before execution.

jQuery get value of select onChange

I was under the impression that I could get the value of a select input by doing this $(this).val();

This works if you subscribe unobtrusively (which is the recommended approach):

$('#id_of_field').change(function() {
    // $(this).val() will work here

if you use onselect and mix markup with script you need to pass a reference to the current element:


and then:

function foo(element) {
    // $(element).val() will give you what you are looking for

Using TortoiseSVN via the command line

After some time, I used this workaround...

(at the .bat file)

SET "CHECKOUT=http://yoururl.url";
SET "PATH=your_folder_path"

start "C:\Program Files\TortoiseSVN\bin" svn.exe checkout %CHECKOUT% %PATH%

How to escape single quotes in MySQL

$var = mysqli_real_escape_string($conn, $_POST['varfield']);

Single Result from Database by using mySQLi

If you assume just one result you could do this as in Edwin suggested by using specific users id.

$someUserId = 'abc123';

$stmt = $mysqli->prepare("SELECT ssfullname, ssemail FROM userss WHERE user_id = ?");
$stmt->bind_param('s', $someUserId);


$stmt->bind_result($ssfullname, $ssemail);

ChromePhp::log($ssfullname, $ssemail); //log result in chrome if ChromePhp is used.

OR as "Your Common Sense" which selects just one user.

$stmt = $mysqli->prepare("SELECT ssfullname, ssemail FROM userss ORDER BY ssid LIMIT 1");

$stmt->bind_result($ssfullname, $ssemail);

Nothing really different from the above except for PHP v.5

Has Facebook sharer.php changed to no longer accept detailed parameters?

If you encode the & in your URL to %26 it works correctly. Just tested and verified.

Which characters make a URL invalid?

In your supplementary question you asked if[/].html is a valid URL.

That URL isn't valid because a URL is a type of URI and a valid URI must have a scheme like http: (see RFC 3986).

If you meant to ask if[/].html is a valid URL then the answer is still no because the square bracket characters aren't valid there.

The square bracket characters are reserved for URLs in this format: http://[2001:db8:85a3::8a2e:370:7334]/foo/bar (i.e. an IPv6 literal instead of a host name)

It's worth reading RFC 3986 carefully if you want to understand the issue fully.

How do I access properties of a javascript object if I don't know the names?

You can loop through keys like this:

for (var key in data) {

This logs "Name" and "Value".

If you have a more complex object type (not just a plain hash-like object, as in the original question), you'll want to only loop through keys that belong to the object itself, as opposed to keys on the object's prototype:

for (var key in data) {
  if (data.hasOwnProperty(key)) {

As you noted, keys are not guaranteed to be in any particular order. Note how this differs from the following:

for each (var value in data) {

This example loops through values, so it would log Property Name and 0. N.B.: The for each syntax is mostly only supported in Firefox, but not in other browsers.

If your target browsers support ES5, or your site includes es5-shim.js (recommended), you can also use Object.keys:

var data = { Name: 'Property Name', Value: '0' };
console.log(Object.keys(data)); // => ["Name", "Value"]

and loop with Array.prototype.forEach:

Object.keys(data).forEach(function (key) {
// => Logs "Property Name", 0

How to hide collapsible Bootstrap 4 navbar on click

With trying out above solutions, I was missing a solution for Dropdown toggles, so here you go! Also opens submenu items.

Maybe you have to tweak it a bit if your toggle class is different.

$('.navbar-nav li a').on('click', function(){
    if(!$( this ).hasClass('dropdown-toggle')){

Open a PDF using VBA in Excel

If it's a matter of just opening PDF to send some keys to it then why not try this

Sub Sample()
    ActiveWorkbook.FollowHyperlink "C:\MyFile.pdf"
End Sub

I am assuming that you have some pdf reader installed.

How to check if a String contains any letter from a to z?

You could use RegEx:

Regex.IsMatch(hello, @"^[a-zA-Z]+$");

If you don't like that, you can use LINQ:


Or, you can loop through the characters, and use isAlpha:


How to add element in Python to the end of list using list.insert?

You'll have to pass the new ordinal position to insert using len in this case:

In [62]:

[1, 2, 3, 4, 5]

Explain why constructor inject is better than other options

With examples? Here's a simple one:

public class TwoInjectionStyles {
    private Foo foo;

    // Constructor injection
    public TwoInjectionStyles(Foo f) { = f;

    // Setting injection
    public void setFoo(Foo f) { = f; }

Personally, I prefer constructor injection when I can.

In both cases, the bean factory instantiates the TwoInjectionStyles and Foo instances and gives the former its Foo dependency.

My docker container has no internet

On centos 8, My problem was that I did not install & start iptables before starting docker service. Make sure iptables service is up and running before you start docker service.

How to add a border to a widget in Flutter?

Best way is using BoxDecoration()


  • You can set border of widget
  • You can set border Color or Width
  • You can set Rounded corner of border
  • You can add Shadow of widget


  • BoxDecoration only use with Container widget so you want to wrap your widget in Container()


      margin: EdgeInsets.all(10),
      padding: EdgeInsets.all(10),
      decoration: BoxDecoration(
        border: Border.all(
            color:[800],// set border color
            width: 3.0),   // set border width
        borderRadius: BorderRadius.all(
            Radius.circular(10.0)), // set rounded corner radius
        boxShadow: [BoxShadow(blurRadius: 10,color:,offset: Offset(1,3))]// make rounded corner of border
      child: Text("My demo styling"),

enter image description here

How to convert Json array to list of objects in c#

Json Convert To C# Class =

after the schema comes out

        WebClient client = new WebClient();

        client.Encoding = Encoding.UTF8;

        string myJSON = client.DownloadString("http://xxx/xx/xx.json");

        var valueSet = JsonConvert.DeserializeObject<Root>(myJSON);

The biggest one of our mistakes is that we can't match the class structure with json.

This connection will do the process automatically. You will code it later ;) =

that's it.

Converting newline formatting from Mac to Windows

In Xcode 9 in the left panel open/choose your file in project navigator. If file is not there, drug-and-drop it into the project navigator.

On right panel find Text Settings and change Line Endings to Windows (CRLF) .

XCode screendumpscreendump from XCode

How to check for null in a single statement in scala?

Although I'm sure @Ben Jackson's asnwer with Option(getObject).foreach is the preferred way of doing it, I like to use an AnyRef pimp that allows me to write:

getObject ifNotNull ( QueueManager.add(_) )

I find it reads better.

And, in a more general way, I sometimes write

val returnVal = getObject ifNotNull { obj =>
} otherwise {

... replacing ifNotNull with ifSome if I'm dealing with an Option. I find it clearer than first wrapping in an option and then pattern-matching it.

(For the implementation, see Implementing ifTrue, ifFalse, ifSome, ifNone, etc. in Scala to avoid if(...) and simple pattern matching and the Otherwise0/Otherwise1 classes.)

How to get the wsdl file from a webservice's URL

By postfixing the URL with ?WSDL

If the URL is for example:


You use:


And the wsdl will be delivered.

How do you get a list of the names of all files present in a directory in Node.js?

Out of the box

In case you want an object with the directory structure out-of-the-box I highly reccomend you to check directory-tree.

Lets say you have this structure:

¦   june
¦   +-- windsurf.jpg
+-- january
    +-- ski.png
    +-- snowboard.jpg
const dirTree = require("directory-tree");
const tree = dirTree("/path/to/photos");

Will return:

  path: "photos",
  name: "photos",
  size: 600,
  type: "directory",
  children: [
      path: "photos/june",
      name: "june",
      size: 400,
      type: "directory",
      children: [
          path: "photos/june/windsurf.jpg",
          name: "windsurf.jpg",
          size: 400,
          type: "file",
          extension: ".jpg"
      path: "photos/january",
      name: "january",
      size: 200,
      type: "directory",
      children: [
          path: "photos/january/ski.png",
          name: "ski.png",
          size: 100,
          type: "file",
          extension: ".png"
          path: "photos/january/snowboard.jpg",
          name: "snowboard.jpg",
          size: 100,
          type: "file",
          extension: ".jpg"

Custom Object

Otherwise if you want to create an directory tree object with your custom settings have a look at the following snippet. A live example is visible on this codesandbox.

// my-script.js
const fs = require("fs");
const path = require("path");

const isDirectory = filePath => fs.statSync(filePath).isDirectory();
const isFile = filePath => fs.statSync(filePath).isFile();

const getDirectoryDetails = filePath => {
  const dirs = fs.readdirSync(filePath);
  return {
    dirs: dirs.filter(name => isDirectory(path.join(filePath, name))),
    files: dirs.filter(name => isFile(path.join(filePath, name)))

const getFilesRecursively = (parentPath, currentFolder) => {
  const currentFolderPath = path.join(parentPath, currentFolder);
  let currentDirectoryDetails = getDirectoryDetails(currentFolderPath);

  const final = {
    current_dir: currentFolder,
    dirs: =>
      getFilesRecursively(currentFolderPath, dir)
    files: currentDirectoryDetails.files

  return final;

const getAllFiles = relativePath => {
  const fullPath = path.join(__dirname, relativePath);
  const parentDirectoryPath = path.dirname(fullPath);
  const leafDirectory = path.basename(fullPath);

  const allFiles = getFilesRecursively(parentDirectoryPath, leafDirectory);
  return allFiles;

module.exports = { getAllFiles };

Then you can simply do:

// another-file.js 

const { getAllFiles } = require("path/to/my-script");

const allFiles = getAllFiles("/path/to/my-directory");

HTML 5 video or audio playlist

you could load next clip in the onend event like that

<script type="text/javascript">
var nextVideo = "path/of/next/video.mp4";
var videoPlayer = document.getElementById('videoPlayer');
videoPlayer.onended = function(){
    videoPlayer.src = nextVideo;
<video id="videoPlayer" src="path/of/current/video.mp4" autoplay autobuffer controls />

More information here

Xcode: failed to get the task for process

I had this issue when trying to debug an App on a device I hadn't used before. Developer profile was correctly set. The device was part of our teams account but wasn't included in my profile.

Simply had to open Organizer -> Select the Device -> Add to Member Center

Specifying number of decimal places in Python

To calculate tax, you could use round (after all, that's what the restaurant does):

def calc_tax(mealPrice):  
    tax = round(mealPrice*.06,2)
    return tax

To display the data, you could use a multi-line string, and the string format method:

def display_data(mealPrice, tax):
Your Meal Price is {m:=5.2f}
Tax                {x:=5.2f}
Total              {t:=5.2f}

Note the format method was introduced in Python 2.6, for earlier versions you'll need to use old-style string interpolation %:

Your Meal Price is %5.2f
Tax                %5.2f
Total              %5.2f




# Enter the meal subtotal: $43.45
# Your Meal Price is 43.45
# Tax                 2.61
# Total              46.06

How to use onClick() or onSelect() on option tag in a JSP page?

Change onClick() from with onChange() in the . You can send the option value to a javascript function.

<select id="selector" onChange="doSomething(document.getElementById(this).options[document.getElementById(this).selectedIndex].value);"> 
<option value="option1"> Option1 </option>
<option value="option2"> Option2 </option>
<option value="optionN"> OptionN </option>

Regex: matching up to the first occurrence of a character

Try /[^;]*/

Google regex character classes for details.

What are DDL and DML?

In layman terms suppose you want to build a house, what do you do.

DDL i.e Data Definition Language

  1. Build from scratch
  2. Rennovate it
  3. Destroy the older one and recreate it from scratch

that is

  2. ALTER

DML i.e. Data Manipulation Language

People come/go inside/from your house


DCL i.e. Data Control Language

You want to control the people what part of the house they are allowed to access and kind of access.


Are "while(true)" loops so bad?

I use something similar, but with opposite logic, in a lot of my functions.


    if ( (dwError = SomeFunction()) != ERROR_SUCCESS )
         /* handle error */

    if ( (dwError = SomeOtherFunction()) != ERROR_SUCCESS )
         /* handle error */
while ( 0 );

if ( dwError != ERROR_SUCCESS )
    /* resource cleanup */

Android on-screen keyboard auto popping up

Add this in parent layout of the XML.


It ensures the focus isn't on the editText when the Activity starts.

How to add style from code behind?


HyperLink hlRow = new HyperLink();
hlRow.Attributes.Add("Style", "color:#000000");

Check if a String is in an ArrayList of Strings

    List list1 = new ArrayList();

    List list2 = new ArrayList();
    list2.add("five"); x -> !list1.contains(x) ).forEach(x -> System.out.println(x));

The output is:


how to set font size based on container size?

I used Fittext on some of my projects and it looks like a good solution to a problem like this.

FitText makes font-sizes flexible. Use this plugin on your fluid or responsive layout to achieve scalable headlines that fill the width of a parent element.

AngularJS - Value attribute on an input text box is ignored when there is a ng-model used?

That's desired behavior, you should define the model in the controller, not in the view.

<div ng-controller="Main">
  <input type="text" ng-model="rootFolders">

function Main($scope) {
  $scope.rootFolders = 'bob';

Setting the Vim background colors

In a terminal emulator like konsole or gnome-terminal, you should to set a 256 color setting for vim.

:set  t_Co=256

After that you can to change your background.

Prevent screen rotation on Android

The following attribute on the ACTIVITY in AndroidManifest.xml is all you need:


So, the full activity node would be:

<activity android:name="Activity1"
          android:label="App Name"
        <action android:name="android.intent.action.MAIN"/>
        <category android:name="android.intent.category.LAUNCHER"/>

Use multiple css stylesheets in the same html page

Think of it as your stylesheet(s) referring to ("selecting") elements in your HTML page, not the other way around.

C++ wait for user input

You can try

#include <iostream>
#include <conio.h>

int main() {

    //some codes

    return 0;

Use of ~ (tilde) in R programming Language

The thing on the right of <- is a formula object. It is often used to denote a statistical model, where the thing on the left of the ~ is the response and the things on the right of the ~ are the explanatory variables. So in English you'd say something like "Species depends on Sepal Length, Sepal Width, Petal Length and Petal Width".

The myFormula <- part of that line stores the formula in an object called myFormula so you can use it in other parts of your R code.

Other common uses of formula objects in R

The lattice package uses them to specify the variables to plot.
The ggplot2 package uses them to specify panels for plotting.
The dplyr package uses them for non-standard evaulation.

Delete all items from a c++ std::vector

vector.clear() is effectively the same as vector.erase( vector.begin(), vector.end() ).

If your problem is about calling delete for each pointer contained in your vector, try this:

#include <algorithm>

template< typename T >
struct delete_pointer_element
    void operator()( T element ) const
        delete element;

// ...
std::for_each( vector.begin(), vector.end(), delete_pointer_element<int*>() );

Edit: Code rendered obsolete by C++11 range-for.

Why is the Visual Studio 2015/2017/2019 Test Runner not discovering my xUnit v2 tests

In my case, I created a new "Solution Configuration" like shown in the image. So when I select my custom one as "Prod", it doesnt recognize TestMehods for some reason. Changing back to "Debug" solves the problem

enter image description here

Why is using onClick() in HTML a bad practice?

If you are using jQuery then:


 <a id="openMap" href="/map/">link</a>


$(document).ready(function() {
        popup('/map/', 300, 300, 'map');
        return false;

This has the benefit of still working without JS, or if the user middle clicks the link.

It also means that I could handle generic popups by rewriting again to:


 <a class="popup" href="/map/">link</a>


$(document).ready(function() {
        popup($(this).attr("href"), 300, 300, 'map');
        return false;

This would let you add a popup to any link by just giving it the popup class.

This idea could be extended even further like so:


 <a class="popup" data-width="300" data-height="300" href="/map/">link</a>


$(document).ready(function() {
        popup($(this).attr("href"), $(this).data('width'), $(this).data('height'), 'map');
        return false;

I can now use the same bit of code for lots of popups on my whole site without having to write loads of onclick stuff! Yay for reusability!

It also means that if later on I decide that popups are bad practice, (which they are!) and that I want to replace them with a lightbox style modal window, I can change:

popup($(this).attr("href"), $(this).data('width'), $(this).data('height'), 'map');


myAmazingModalWindow($(this).attr("href"), $(this).data('width'), $(this).data('height'), 'map');

and all my popups on my whole site are now working totally differently. I could even do feature detection to decide what to do on a popup, or store a users preference to allow them or not. With the inline onclick, this requires a huge copy and pasting effort.

WCF timeout exception detailed investigation


To avoid this timeout error, we need to configure the OperationTimeout property for Proxy in the WCF client code. This configuration is something new unlike other configurations such as Send Timeout, Receive Timeout etc., which I discussed early in the article. To set this operation timeout property configuration, we have to cast our proxy to IContextChannel in WCF client application before calling the operation contract methods.

Android Studio - Unable to find valid certification path to requested target

I had the same issue and it was caused because cyberoam was blocking my following URL

Caused by: org.gradle.api.resources.ResourceException: Unable to load Maven meta-data from

Perform Segue programmatically and pass parameters to the destination view

In case if you use new swift version.

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "ChannelMoreSegue" {


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

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

# On sample data from @Aus_10

df %>%

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

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

To not include the grouping column:

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

Where does flask look for image files?

It took me a while to figure this out too. url_for in Flask looks for endpoints that you specified in the script.

So if you have a decorator in your file like @blah.route('/folder.subfolder') then Flask will recognize the command {{ url_for('folder.subfolder') , filename = "some_image.jpg" }} . The 'folder.subfolder' argument sends it to a Flask endpoint it recognizes.

However let us say that you stored your image file, some_image.jpg, in your subfolder, BUT did not specify this subfolder as a route endpoint in your flask, your route decorator looks like @blah.routes('/folder'). You then have to ask for your image file this way: {{ url_for('folder'), filename = 'subfolder/some_image.jpg' }}

I.E. you tell Flask to go to the endpoint it knows, "folder", then direct it from there by putting the subdirectory path in the filename argument.

SQL Server add auto increment primary key to existing table

No - you have to do it the other way around: add it right from the get go as INT IDENTITY - it will be filled with identity values when you do this:

ALTER TABLE dbo.YourTable

and then you can make it the primary key:

ALTER TABLE dbo.YourTable

or if you prefer to do all in one step:

ALTER TABLE dbo.YourTable

How to add new line in Markdown presentation?

I was using Markwon for markdown parsing in Android. The following worked great:

"My first line  \nMy second line  \nMy third line  \nMy last line"

...two spaces followed by \n at the end of each line.

PHP: How to handle <![CDATA[ with SimpleXMLElement?

When to use LIBXML_NOCDATA ?

I add the issue when transforming XML to JSON.

$xml = simplexml_load_string("<foo><content><![CDATA[Hello, world!]]></content></foo>");
echo json_encode($xml, true); 
/* prints
     "content": {}

When accessing the SimpleXMLElement object, It gets the CDATA :

$xml = simplexml_load_string("<foo><content><![CDATA[Hello, world!]]></content></foo>");
echo $xml->content; 
/* prints
   Hello, world!

I makes sense to use LIBXML_NOCDATA because json_encode don't access the SimpleXMLElement to trigger the string casting feature, I'm guessing a __toString() equivalent.

$xml = simplexml_load_string("<foo><content><![CDATA[Hello, world!]]></content></foo>", null, LIBXML_NOCDATA);
echo json_encode($xml);
   "content": "Hello, world!"

How to identify unused CSS definitions from multiple CSS files in a project

I have just found this site –

Looks good but I would need to thoroughly check its outputted 'clean' css before uploading it to any of my sites.

Also as with all these tools I would need to check it didn't strip id's and classes with no style but are used as JavaScript selectors.

The below content is taken from so credit to them for recommending other solutions:

Latish Sehgal has written a windows application to find and remove unused CSS classes. I haven't tested it but from the description, you have to provide the path of your html files and one CSS file. The program will then list the unused CSS selectors. From the screenshot, it looks like there is no way to export this list or download a new clean CSS file. It also looks like the service is limited to one CSS file. If you have multiple files you want to clean, you have to clean them one by one.

Dust-Me Selectors is a Firefox extension (for v1.5 or later) that finds unused CSS selectors. It extracts all the selectors from all the stylesheets on the page you're viewing, then analyzes that page to see which of those selectors are not used. The data is then stored so that when testing subsequent pages, selectors can be crossed off the list as they're encountered. This tool is supposed to be able to spider a whole website but I unfortunately could make it work. Also, I don't believe you can configure and download the CSS file with the styles removed.

Topstyle is a windows application including a bunch of tools to edit CSS. I haven't tested it much but it looks like it has the ability to removed unused CSS selectors. This software costs 80 USD.

Liquidcity CSS cleaner is a php script that uses regular expressions to check the styles of one page. It will tell you the classes that aren't available in the HTML code. I haven't tested this solution.

Deadweight is a CSS coverage tool. Given a set of stylesheets and a set of URLs, it determines which selectors are actually used and lists which can be "safely" deleted. This tool is a ruby module and will only work with rails website. The unused selectors have to be manually removed from the CSS file.

Helium CSS is a javascript tool for discovering unused CSS across many pages on a web site. You first have to install the javascript file to the page you want to test. Then, you have to call a helium function to start the cleaning. is web application with an easy to use interface. Type the url of a site and you will get a list of CSS selectors. For each selector, a number indicates how many times a selector is used. This service has a few limitations. The @import statement is not supported. You can't configure and download the new clean CSS file.

CSSESS is a bookmarklet that helps you find unused CSS selectors on any site. This tool is pretty easy to use but it won't let you configure and download clean CSS files. It will only list unused CSS files.

Bootstrap 3: Using img-circle, how to get circle from non-square image?

the problem mainly is because the width have to be == to the height, and in the case of bs, the height is set to auto so here is a fix for that in js instead

function img_circle() {
    $('.img-circle').each(function() {
        $w = $(this).width();

$(document).ready(function() {

$(window).resize(function() {

Bootstrap Element 100% Width

In bootstrap 4, you can use 'w-100' class (w as width, and 100 as 100%)

You can find documentation here:

JavaScript CSS how to add and remove multiple CSS classes to an element

In modern browsers, the classList API is supported.

This allows for a (vanilla) JavaScript function like this:

var addClasses;

addClasses = function (selector, classArray) {
    'use strict';

    var className, element, elements, i, j, lengthI, lengthJ;

    elements = document.querySelectorAll(selector);

    // Loop through the elements
    for (i = 0, lengthI = elements.length; i < lengthI; i += 1) {
        element = elements[i];

        // Loop through the array of classes to add one class at a time
        for (j = 0, lengthJ = classArray.length; j < lengthJ; j += 1) {
            className = classArray[j];


Modern browsers (not IE) support passing multiple arguments to the classList::add function, which would remove the need for the nested loop, simplifying the function a bit:

var addClasses;

addClasses = function (selector, classArray) {
    'use strict';

    var classList, className, element, elements, i, j, lengthI, lengthJ;

    elements = document.querySelectorAll(selector);

    // Loop through the elements
    for (i = 0, lengthI = elements.length; i < lengthI; i += 1) {
        element = elements[i];
        classList = element.classList;

        // Pass the array of classes as multiple arguments to classList::add
        classList.add.apply(classList, classArray);


addClasses('.button', ['large', 'primary']);

Functional version

var addClassesToElement, addClassesToSelection;

addClassesToElement = function (element, classArray) {
    'use strict';

    classArray.forEach(function (className) {

addClassesToSelection = function (selector, classArray) {
    'use strict';

    // Use Array::forEach on NodeList to iterate over results.
    // Okay, since we’re not trying to modify the NodeList., function (element) {
        addClassesToElement(element, classArray)

// Usage
addClassesToSelection('.button', ['button', 'button--primary', 'button--large'])

The classList::add function will prevent multiple instances of the same CSS class as opposed to some of the previous answers.

Resources on the classList API:

How to get commit history for just one branch?

The git merge-base command can be used to find a common ancestor. So if my_experiment has not been merged into master yet and my_experiment was created from master you could:

git log --oneline `git merge-base my_experiment master`..my_experiment

Execute multiple command lines with the same process using .NET

You could also tell MySQL to execute the commands in the given file, like so:

mysql --user=root --password=sa casemanager < CaseManager.sql

Set LIMIT with doctrine 2?

$limit=5; // for exemple

$query = $this->getDoctrine()->getEntityManager()->createQuery(
           '// your request')


 $results = $query->getResult();

// Done

org.hibernate.MappingException: Could not determine type for: java.util.List, at table: College, for columns: [org.hibernate.mapping.Column(students)]

In case anyone else lands here with the same issue I encountered. I was getting the same error as above:

Invocation of init method failed; nested exception is org.hibernate.MappingException: Could not determine type for: java.util.Collection, at table:

Hibernate uses reflection to determine which columns are in an entity. I had a private method that started with 'get' and returned an object that was also a hibernate entity. Even private getters that you want hibernate to ignore have to be annotated with @Transient. Once I added the @Transient annotation everything worked.

private List<AHibernateEntity> getHibernateEntities() {

How to execute an Oracle stored procedure via a database link

The syntax is

EXEC mySchema.myPackage.myProcedure@myRemoteDB( 'someParameter' );

When using Spring Security, what is the proper way to obtain current username (i.e. SecurityContext) information in a bean?

The only problem is that even after authenticating with Spring Security, the user/principal bean doesn't exist in the container, so dependency-injecting it will be difficult. Before we used Spring Security we would create a session-scoped bean that had the current Principal, inject that into an "AuthService" and then inject that Service into most of the other services in the Application. So those Services would simply call authService.getCurrentUser() to get the object. If you have a place in your code where you get a reference to the same Principal in the session, you can simply set it as a property on your session-scoped bean.

Could not load file or assembly System.Net.Http, Version= with ASP.NET (MVC 4) Web API OData Prerelease

Visual Studio 2013 has a new feature to take care of this. When you build the app, you should see warnings about different versions of an assembly being referenced. Double click the warning to add assembly binding redirects to the web.config.

See for more details.

jeff.eynon notes below that you need to have the web.config checked out (if using TFS source control) to get VS to edit the file automatically. Thanks for the tip!

jquery - Click event not working for dynamically created button

My guess is that the buttons you created are not yet on the page by the time you bind the button. Either bind each button in the $.getJSON function, or use a dynamic binding method like:

$('body').on('click', 'button', function() {

Note you probably don't want to do this on the 'body' tag, but instead wrap the buttons in another div or something and call on on it.

jQuery On Method

How do I correct this Illegal String Offset?

I get the same error in WP when I use php ver 7.1.6 - just take your php version back to 7.0.20 and the error will disappear.

How to Remove the last char of String in C#?

newString = yourString.Substring(0, yourString.length -1);

How can I calculate the difference between two ArrayLists?

EDIT: Original question did not specify language. My answer is in C#.

You should instead use HashSet for this purpose. If you must use ArrayList, you could use the following extension methods:

var a = arrayListA.Cast<DateTime>();
var b = arrayListB.Cast<DateTime>();    
var c = b.Except(a);

var arrayListC = new ArrayList(c.ToArray());

using HashSet...

var a = new HashSet<DateTime>(); // ...and fill it
var b = new HashSet<DateTime>(); // ...and fill it
b.ExceptWith(a); // removes from b items that are in a

How to programmatically send SMS on the iPhone?

One of the systems of inter-process communication in MacOS is XPC. This system layer has been developed for inter-process communication based on the transfer of plist structures using libSystem and launchd. In fact, it is an interface that allows managing processes via the exchange of such structures as dictionaries. Due to heredity, iOS 5 possesses this mechanism as well.

You might already understand what I mean by this introduction. Yep, there are system services in iOS that include tools for XPC communication. And I want to exemplify the work with a daemon for SMS sending. However, it should be mentioned that this ability is fixed in iOS 6, but is relevant for iOS 5.0—5.1.1. Jailbreak, Private Framework, and other illegal tools are not required for its exploitation. Only the set of header files from the directory /usr/include/xpc/* are needed.

One of the elements for SMS sending in iOS is the system service, the tasks of which include generation, management, and sending of short text messages. For the ease of control, it has the publicly available communication port Using the XPC subsystem, you can generate and send messages without user's approval.

Well, let's try to create a connection.

xpc_connection_t myConnection;

dispatch_queue_t queue = dispatch_queue_create("", DISPATCH_QUEUE_CONCURRENT);

myConnection = xpc_connection_create_mach_service("", queue, XPC_CONNECTION_MACH_SERVICE_PRIVILEGED);

Now we have the XPC connection myConnection set to the service of SMS sending. However, XPC configuration provides for creation of suspended connections —we need to take one more step for the activation.

xpc_connection_set_event_handler(myConnection, ^(xpc_object_t event){
xpc_type_t xtype = xpc_get_type(event);
if(XPC_TYPE_ERROR == xtype)
NSLog(@"XPC sandbox connection error: %s\n", xpc_dictionary_get_string(event, XPC_ERROR_KEY_DESCRIPTION));
// Always set an event handler. More on this later.

NSLog(@"Received a message event!");



The connection is activated. Right at this moment iOS 6 will display a message in the telephone log that this type of communication is forbidden. Now we need to generate a dictionary similar to xpc_dictionary with the data required for the message sending.

NSArray *recipient = [NSArray arrayWithObjects:@"+7 (90*) 000-00-00", nil];

NSData *ser_rec = [NSPropertyListSerialization dataWithPropertyList:recipient format:200 options:0 error:NULL];

xpc_object_t mydict = xpc_dictionary_create(0, 0, 0);
xpc_dictionary_set_int64(mydict, "message-type", 0);
xpc_dictionary_set_data(mydict, "recipients", [ser_rec bytes], [ser_rec length]);
xpc_dictionary_set_string(mydict, "text", "hello from your application!");

Little is left: send the message to the XPC port and make sure it is delivered.

xpc_connection_send_message(myConnection, mydict);
xpc_connection_send_barrier(myConnection, ^{
NSLog(@"The message has been successfully delivered");

That's all. SMS sent.

How to explicitly obtain post data in Spring MVC?

You can simply just pass the attribute you want without any annotations in your controller:

@RequestMapping(value = "/someUrl")
public String someMethod(String valueOne) {
 //do stuff with valueOne variable here

Works with GET and POST

Linux: Which process is causing "device busy" when doing umount?

If you still can not unmount or remount your device after stopping all services and processes with open files, then there may be a swap file or swap partition keeping your device busy. This will not show up with fuser or lsof. Turn off swapping with:

sudo swapoff -a

You could check beforehand and show a summary of any swap partitions or swap files with:

swapon -s


cat /proc/swaps

As an alternative to using the command sudo swapoff -a, you might also be able to disable the swap by stopping a service or systemd unit. For example:

sudo systemctl stop dphys-swapfile


sudo systemctl stop var-swap.swap

In my case, turning off swap was necessary, in addition to stopping any services and processes with files open for writing, so that I could remount my root partition as read only in order to run fsck on my root partition without rebooting. This was necessary on a Raspberry Pi running Raspbian Jessie.

What is the difference between an int and a long in C++?

It depends on your compiler. You are guaranteed that a long will be at least as large as an int, but you are not guaranteed that it will be any longer.

JSLint says "missing radix parameter"

I solved it with just using the +foo, to convert the string.

Keep in mind it's not great for readability (dirty fix).

console.log( +'1' )
// 1 (int)

PHP Configuration: It is not safe to rely on the system's timezone settings

Obviously I'm a little out of season on this question but for the benefit of the next sufferer: I just had this problem and in my case (in contrast to OP who tried the same without success) the fix was to revise php.ini, changing

date.timezone = America/New York


date.timezone = America/New_York

That is adding the underscore.

PHP str_replace replace spaces with underscores

Try this instead:

$journalName = preg_replace('/\s+/', '_', $journalName);

Explanation: you are most likely seeing whitespace, not just plain spaces (there is a difference).

Is there any "font smoothing" in Google Chrome?

Chrome doesn't render the fonts like Firefox or any other browser does. This is generally a problem in Chrome running on Windows only. If you want to make the fonts smooth, use the -webkit-font-smoothing property on yer h4 tags like this.

h4 {
    -webkit-font-smoothing: antialiased;

You can also use subpixel-antialiased, this will give you different type of smoothing (making the text a little blurry/shadowed). However, you will need a nightly version to see the effects. You can learn more about font smoothing here.

Creating columns in listView and add items

I didn't see anyone answer this correctly. So I'm posting it here. In order to get columns to show up you need to specify the following line.

lvRegAnimals.View = View.Details;

And then add your columns after that.

lvRegAnimals.Columns.Add("Id", -2, HorizontalAlignment.Left);
lvRegAnimals.Columns.Add("Name", -2, HorizontalAlignment.Left);
lvRegAnimals.Columns.Add("Age", -2, HorizontalAlignment.Left);

Hope this helps anyone else looking for this answer in the future.

How to transition to a new view controller with code only using Swift


Usually for normal transition we use,

let next:SecondViewController = SecondViewController()
self.presentViewController(next, animated: true, completion: nil)

But sometimes when using navigation controller, you might face a black screen. In that case, you need to use like,

let next:ThirdViewController = storyboard?.instantiateViewControllerWithIdentifier("ThirdViewController") as! ThirdViewController
self.navigationController?.pushViewController(next, animated: true)

Moreover none of the above solution preserves navigationbar when you call from storyboard or single xib to another xib. If you use nav bar and want to preserve it just like normal push, you have to use,

Let's say, "MyViewController" is identifier for MyViewController

let viewController = MyViewController(nibName: "MyViewController", bundle: nil)
self.navigationController?.pushViewController(viewController, animated: true)

Java Currency Number format

NumberFormat currency = NumberFormat.getCurrencyInstance();
String myCurrency = currency.format(123.5);



If you want to change the currency,

NumberFormat currency = NumberFormat.getCurrencyInstance(Locale.CHINA);
String myCurrency = currency.format(123.5);



Get JSON Data from URL Using Android?

If you get the server response as a String, without using a third party library you can do

JSONObject json = new JSONObject(response);
JSONObject jsonResponse = json.getJSONObject("response");
String team = jsonResponse.getString("Team");

Here is the documentation

Otherwise to parse json you can use Gson or Jackson

EDIT without libraries (not tested)

class retrievedata extends AsyncTask<Void, Void, String>{
    protected String doInBackground(Void... params) {

        HttpURLConnection urlConnection = null;
        BufferedReader reader = null;

        URL url;
        try {
            url = new URL("");
            urlConnection.setRequestMethod("GET"); //Your method here 

            InputStream inputStream = urlConnection.getInputStream();
            StringBuffer buffer = new StringBuffer();
            if (inputStream == null) {
                return null;
            reader = new BufferedReader(new InputStreamReader(inputStream));

            String line;
            while ((line = reader.readLine()) != null)
                buffer.append(line + "\n");

            if (buffer.length() == 0)
                return null;

            return buffer.toString();
        } catch (IOException e) {
            Log.e(TAG, "IO Exception", e);
            exception = e;
            return null;
        } finally {
            if (urlConnection != null) {
            if (reader != null) {
                try {
                } catch (final IOException e) {
                    exception = e;
                    Log.e(TAG, "Error closing stream", e);

    protected void onPostExecute(String response) {
        if(response != null) {
            JSONObject json = new JSONObject(response);
            JSONObject jsonResponse = json.getJSONObject("response");
            String team = jsonResponse.getString("Team");

How can I adjust DIV width to contents

You could try using float:left; or display:inline-block;.

Both of these will change the element's behaviour from defaulting to 100% width to defaulting to the natural width of its contents.

However, note that they'll also both have an impact on the layout of the surrounding elements as well. I would suggest that inline-block will have less of an impact though, so probably best to try that first.

Excel VBA date formats

To ensure that a cell will return a date value and not just a string that looks like a date, first you must set the NumberFormat property to a Date format, then put a real date into the cell's content.

Sub test_date_or_String()
 Set c = ActiveCell
 c.NumberFormat = "@"
 c.Value = CDate("03/04/2014")
   Debug.Print c.Value & " is a " & TypeName(c.Value) 'C is a String
 c.NumberFormat = "m/d/yyyy"
   Debug.Print c.Value & " is a " & TypeName(c.Value) 'C is still a String
 c.Value = CDate("03/04/2014")
   Debug.Print c.Value & " is a " & TypeName(c.Value) 'C is a date    
End Sub

Compare two files and write it to "match" and "nomatch" files

Though its really long back this question was posted, I wish to answer as it might help others. This can be done easily by means of JOINKEYS in a SINGLE step. Here goes the pseudo code:

  • Code JOINKEYS PAIRED(implicit) and get both the records via reformatting filed. If there is NO match from either of files then append/prefix some special character say '$'
  • Compare via IFTHEN for '$', if exists then it doesnt have a paired record, it'll be written into unpaired file and rest to paired file.

Please do get back incase of any questions.

Looping Over Result Sets in MySQL

Use cursors.

A cursor can be thought of like a buffered reader, when reading through a document. If you think of each row as a line in a document, then you would read the next line, perform your operations, and then advance the cursor.

Python constructor and default value

Mutable default arguments don't generally do what you want. Instead, try this:

class Node:
     def __init__(self, wordList=None, adjacencyList=None):
        if wordList is None:
            self.wordList = []
             self.wordList = wordList 
        if adjacencyList is None:
            self.adjacencyList = []
             self.adjacencyList = adjacencyList 

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

I was using IntelliJ IDEA 13.1.5 and faced with the same problem after I changed versions of Picasso and Retrofit in dependencies in build.gradle file. I tried use many solutions, but without result. Then I cloned my project from remote git (where I pushed it before changing versions of dependencies) and it worked! After that I just closed current project and imported old project from Gradle file to IntelliJ IDEA again and it worked too! So, I think it was strange bug in intersection of IDEA, Gradle and Android plugin. I hope this information can be useful for IDEA-users or anyone else.

LINQ query to return a Dictionary<string, string>

Use the ToDictionary method directly.

var result = 
  // as Jon Skeet pointed out, OrderBy is useless here, I just leave it 
  // show how to use OrderBy in a LINQ query
  myClassCollection.OrderBy(mc => mc.SomePropToSortOn)
                   .ToDictionary(mc => mc.KeyProp.ToString(), 
                                 mc => mc.ValueProp.ToString(), 

Static linking vs dynamic linking

1) is based on the fact that calling a DLL function is always using an extra indirect jump. Today, this is usually negligible. Inside the DLL there is some more overhead on i386 CPU's, because they can't generate position independent code. On amd64, jumps can be relative to the program counter, so this is a huge improvement.

2) This is correct. With optimizations guided by profiling you can usually win about 10-15 percent performance. Now that CPU speed has reached its limits it might be worth doing it.

I would add: (3) the linker can arrange functions in a more cache efficient grouping, so that expensive cache level misses are minimised. It also might especially effect the startup time of applications (based on results i have seen with the Sun C++ compiler)

And don't forget that with DLLs no dead code elimination can be performed. Depending on the language, the DLL code might not be optimal either. Virtual functions are always virtual because the compiler doesn't know whether a client is overwriting it.

For these reasons, in case there is no real need for DLLs, then just use static compilation.

EDIT (to answer the comment, by user underscore)

Here is a good resource about the position independent code problem

As explained x86 does not have them AFAIK for anything else then 15 bit jump ranges and not for unconditional jumps and calls. That's why functions (from generators) having more then 32K have always been a problem and needed embedded trampolines.

But on popular x86 OS like Linux you do not need to care if the .so/DLL file is not generated with the gcc switch -fpic (which enforces the use of the indirect jump tables). Because if you don't, the code is just fixed like a normal linker would relocate it. But while doing this it makes the code segment non shareable and it would need a full mapping of the code from disk into memory and touching it all before it can be used (emptying most of the caches, hitting TLBs) etc. There was a time when this was considered slow.

So you would not have any benefit anymore.

I do not recall what OS (Solaris or FreeBSD) gave me problems with my Unix build system because I just wasn't doing this and wondered why it crashed until I applied -fPIC to gcc.

window.onload vs <body onload=""/>

window.onload - Called after all DOM, JS files, Images, Iframes, Extensions and others completely loaded. This is equal to $(window).load(function() {});

body onload="" - Called once DOM loaded. This is equal to $(document).ready(function() {});

Illegal character in path at index 16

I had a similar problem for xml. Just passing the error and solution (edited Jonathon version).


HttpGet xmlGet = new HttpGet( xmlContent );

Xml format:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>


java.lang.IllegalArgumentException: Illegal character in path at index 0: <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    at org.apache.http.client.methods.HttpGet.<init>(
    at de.vogella.jersey.first.Hello.validate(

Not Exactly perfect Solution: ( error vanished for that instance )

String theXml = URLEncoder.encode( xmlContent, "UTF-8" );
HttpGet xmlGet = new HttpGet( theXml );

Any idea What i should be doing ? It just cleared passed but had problem while doing this

HttpResponse response = httpclient.execute( xmlGet );

'mvn' is not recognized as an internal or external command, operable program or batch file

Go to Environment Variable and paste the following:

Under System Variable: Step 1: New --> New User Variable 1. Variable name: MAVEN_HOME 2. Variable_value : D:\apache-maven-3.5.2

Step 2: 1. Go to the path --> and paste this - %MAVEN_HOME%\bin

How to prevent a dialog from closing when a button is clicked

Here's something if you are using DialogFragment - which is the recommended way to handle Dialogs anyway.

What happens with AlertDialog's setButton() method (and I imagine the same with AlertDialogBuilder's setPositiveButton() and setNegativeButton()) is that the button you set (e.g. AlertDialog.BUTTON_POSITIVE) with it will actually trigger TWO different OnClickListener objects when pressed.

The first being DialogInterface.OnClickListener, which is a parameter to setButton(), setPositiveButton(), and setNegativeButton().

The other is View.OnClickListener, which will be set to automatically dismiss your AlertDialog when any of its button is pressed - and is set by AlertDialog itself.

What you can do is to use setButton() with null as the DialogInterface.OnClickListener, to create the button, and then call your custom action method inside View.OnClickListener. For example,

public Dialog onCreateDialog(Bundle savedInstanceState)
    AlertDialog alertDialog = new AlertDialog(getActivity());
    // set more items...
    alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK", null);

    return alertDialog;

Then, you may override the default AlertDialog's buttons' View.OnClickListener (which would otherwise dismiss the dialog) in the DialogFragment's onResume() method:

public void onResume()
    AlertDialog alertDialog = (AlertDialog) getDialog();
    Button okButton = alertDialog.getButton(AlertDialog.BUTTON_POSITIVE);
    okButton.setOnClickListener(new View.OnClickListener() { 
        public void onClick(View v)

private void performOkButtonAction() {
    // Do your stuff here

You will need to set this in the onResume() method because getButton() will return null until after the dialog has been shown!

This should cause your custom action method to only be called once, and the dialog won't be dismissed by default.

convert iso date to milliseconds in javascript

Another solution could be to use Number object parser like this:

let result = Number(new Date("2012-02-10T13:19:11+0000"));_x000D_
let resultWithGetTime = (new Date("2012-02-10T13:19:11+0000")).getTime();_x000D_

This converts to milliseconds just like getTime() on Date object

How do I find out my root MySQL password?

MySQL 5.5 on Ubuntu 14.04 required slightly different commands as recommended here. In a nutshell:

sudo /etc/init.d/mysql stop
sudo /usr/sbin/mysqld --skip-grant-tables --skip-networking &
mysql -u root

And then from the MySQL prompt

SET PASSWORD FOR root@'localhost' = PASSWORD('password');
UPDATE mysql.user SET Password=PASSWORD('newpwd') WHERE User='root';

And the cited source offers an alternate method as well.

How can I verify if an AD account is locked?

I found also this list of property flags: How to use the UserAccountControl flags

SCRIPT  0x0001  1
LOCKOUT 0x0010  16
PASSWD_NOTREQD  0x0020  32
NORMAL_ACCOUNT  0x0200  512
SERVER_TRUST_ACCOUNT    0x2000  8192
DONT_EXPIRE_PASSWORD    0x10000 65536
MNS_LOGON_ACCOUNT   0x20000 131072
SMARTCARD_REQUIRED  0x40000 262144
NOT_DELEGATED   0x100000    1048576
USE_DES_KEY_ONLY    0x200000    2097152
DONT_REQ_PREAUTH    0x400000    4194304
PASSWORD_EXPIRED    0x800000    8388608
TRUSTED_TO_AUTH_FOR_DELEGATION  0x1000000   16777216
PARTIAL_SECRETS_ACCOUNT 0x04000000      67108864

You must make a binary-AND of property userAccountControl with 0x002. In order to get all locked (i.e. disabled) accounts you can filter on this:


For operator 1.2.840.113556.1.4.803 see LDAP Matching Rules

Visual Studio Copy Project

My solution is a little bit different - the computer that the package resided on died and so I was forced to recreate it on another computer.

What I did (in VS 2008) was to open the following files in my directory:

                  - <package name>.djproj
                  - <package name>.dtproj.user
                  - <package name>.dtxs
                  - <package name>.sln
                  - Package.dtsx

When I did this a popup window asked me if the sln file was going to be a new solution and when I clicked 'yes' everything worked perfectly.

Object Library Not Registered When Adding Windows Common Controls 6.0

...and on my 64 bit W7 machine, with VB6 installed... in DOS, as Admin, this worked to solve an OCX problem I was having with a VB6 App:

cd C:\Windows\SysWOW64
regsvr32 mscomctl.ocx
regtlib msdatsrc.tlb

YES! This solution solved the problem I had using MSCAL.OCX (The Microsoft Calendar Control) in VB6.

Thank you guys! :-)

How to get changes from another branch

  1. go to the master branch our-team

    • git checkout our-team
  2. pull all the new changes from our-team branch

    • git pull
  3. go to your branch featurex

    • git checkout featurex
  4. merge the changes of our-team branch into featurex branch

    • git merge our-team
    • or git cherry-pick {commit-hash} if you want to merge specific commits
  5. push your changes with the changes of our-team branch

    • git push

Note: probably you will have to fix conflicts after merging our-team branch into featurex branch before pushing

Get bytes from std::string in C++

If you just need read-only access, then c_str() will do it:

char const *c = myString.c_str();

If you need read/write access, then you can copy the string into a vector. vectors manage dynamic memory for you. You don't have to mess with allocation/deallocation then:

std::vector<char> bytes(myString.begin(), myString.end());
char *c = &bytes[0];

"Automatic" vs "Automatic (Delayed start)"

In short, services set to Automatic will start during the boot process, while services set to start as Delayed will start shortly after boot.

Starting your service Delayed improves the boot performance of your server and has security benefits which are outlined in the article Adriano linked to in the comments.

Update: "shortly after boot" is actually 2 minutes after the last "automatic" service has started, by default. This can be configured by a registry key, according to Windows Internals and other sources (3,4).

The registry keys of interest (At least in some versions of windows) are:

  • HKLM\SYSTEM\CurrentControlSet\services\<service name>\DelayedAutostart will have the value 1 if delayed, 0 if not.
  • HKLM\SYSTEM\CurrentControlSet\services\AutoStartDelay or HKLM\SYSTEM\CurrentControlSet\Control\AutoStartDelay (on Windows 10): decimal number of seconds to wait, may need to create this one. Applies globally to all Delayed services.

How can I convert byte size into a human-readable format in Java?

Fun fact: The original snippet posted here was the most copied Java snippet of all time on Stack Overflow, and it was flawed. It was fixed, but it got messy.

Full story in this article: The most copied Stack Overflow snippet of all time is flawed!

Source: Formatting byte size to human readable format | Programming.Guide

SI (1 k = 1,000)

public static String humanReadableByteCountSI(long bytes) {
    if (-1000 < bytes && bytes < 1000) {
        return bytes + " B";
    CharacterIterator ci = new StringCharacterIterator("kMGTPE");
    while (bytes <= -999_950 || bytes >= 999_950) {
        bytes /= 1000;;
    return String.format("%.1f %cB", bytes / 1000.0, ci.current());

Binary (1 Ki = 1,024)

public static String humanReadableByteCountBin(long bytes) {
    long absB = bytes == Long.MIN_VALUE ? Long.MAX_VALUE : Math.abs(bytes);
    if (absB < 1024) {
        return bytes + " B";
    long value = absB;
    CharacterIterator ci = new StringCharacterIterator("KMGTPE");
    for (int i = 40; i >= 0 && absB > 0xfffccccccccccccL >> i; i -= 10) {
        value >>= 10;;
    value *= Long.signum(bytes);
    return String.format("%.1f %ciB", value / 1024.0, ci.current());

Example output:

                              SI     BINARY

                   0:        0 B        0 B
                  27:       27 B       27 B
                 999:      999 B      999 B
                1000:     1.0 kB     1000 B
                1023:     1.0 kB     1023 B
                1024:     1.0 kB    1.0 KiB
                1728:     1.7 kB    1.7 KiB
              110592:   110.6 kB  108.0 KiB
             7077888:     7.1 MB    6.8 MiB
           452984832:   453.0 MB  432.0 MiB
         28991029248:    29.0 GB   27.0 GiB
       1855425871872:     1.9 TB    1.7 TiB
 9223372036854775807:     9.2 EB    8.0 EiB   (Long.MAX_VALUE)

Difference between numpy dot() and Python 3.5+ matrix multiplication @

My experience with MATMUL and DOT

I was constantly getting "ValueError: Shape of passed values is (200, 1), indices imply (200, 3)" when trying to use MATMUL. I wanted a quick workaround and found DOT to deliver the same functionality. I don't get any error using DOT. I get the correct answer


>>>(200, 3)




>>>array([0.37454012, 0.95071431, 0.73199394])

YY = np.matmul(X,w)

>>>  ValueError: Shape of passed values is (200, 1), indices imply (200, 3)"

with DOT

YY =,w)
# no error message
>>>array([ 2.59206877,  1.06842193,  2.18533396,  2.11366346,  0.28505879, …


>>> (200, )

How to simulate POST request?

Postman is the best application to test your APIs !

You can import or export your routes and let him remember all your body requests ! :)

EDIT : This comment is 5 yea's old and deprecated :D

Here's the new Postman App :

How to save RecyclerView's scroll position using RecyclerView.State?

In my case I was setting the RecyclerView's layoutManager both in XML and in onViewCreated. Removing the assignment in onViewCreated fixed it.

with(_binding.list) {
//  layoutManager =  LinearLayoutManager(context)
    adapter = MyAdapter().apply {,
            Observer {
                it?.let { setItems(it) }

How do I rename a local Git branch?

Here are the steps to rename the branch:

  1. Switch to the branch which needs to be renamed
  2. git branch -m <new_name>
  3. git push origin :<old_name>
  4. git push origin <new_name>:refs/heads/<new_name>

EDIT (12/01/2017): Make sure you run command git status and check that the newly created branch is pointing to its own ref and not the older one. If you find the reference to the older branch, you need to unset the upstream using:

git branch --unset-upstream

"fatal: Not a git repository (or any of the parent directories)" from git status

In my case, the original repository was a bare one.

So, I had to type (in windows):

mkdir   dest
cd dest
git init
git remote add origin a\valid\yet\bare\repository
git pull origin master

To check if a repository is a bare one:

git rev-parse --is-bare-repository 

How to install and run Typescript locally in npm?

You need to tell npm that "tsc" exists as a local project package (via the "scripts" property in your package.json) and then run it via npm run tsc. To do that (at least on Mac) I had to add the path for the actual compiler within the package, like this

  "name": "foo"
  "scripts": {
    "tsc": "./node_modules/typescript/bin/tsc"
  "dependencies": {
    "typescript": "^2.3.3",
    "typings": "^2.1.1"

After that you can run any TypeScript command like npm run tsc -- --init (the arguments come after the first --).

Reading a List from properties file and load with spring annotation @Value

If you are using latest Spring framework version(Spring 3.1+ I believe), you don't need to those string split stuff in SpringEL,

Simply add PropertySourcesPlaceholderConfigurer and DefaultConversionService in your Spring's Configuration class ( the one with annotated with Configuration ) e.g,

public class AppConfiguration {

    public static PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();

    @Bean public ConversionService conversionService() {
        return new DefaultConversionService();

and in your class

private List<String> list;

and in the properties file


Without DefaultConversionService, you can only take comma separated String into String array when you inject the value into your field, but DefaultConversionService does a few convenient magic for you and will add those into Collection, Array, etc. ( check the implementation if you'd like to know more about it )

With these two, it even handles all the redundant whitespaces including newline, so you don't need to add additional logics to trim them.

Where/How to getIntent().getExtras() in an Android Fragment?

What I tend to do, and I believe this is what Google intended for developers to do too, is to still get the extras from an Intent in an Activity and then pass any extra data to fragments by instantiating them with arguments.

There's actually an example on the Android dev blog that illustrates this concept, and you'll see this in several of the API demos too. Although this specific example is given for API 3.0+ fragments, the same flow applies when using FragmentActivity and Fragment from the support library.

You first retrieve the intent extras as usual in your activity and pass them on as arguments to the fragment:

public static class DetailsActivity extends FragmentActivity {

    protected void onCreate(Bundle savedInstanceState) {

        // (omitted some other stuff)

        if (savedInstanceState == null) {
            // During initial setup, plug in the details fragment.
            DetailsFragment details = new DetailsFragment();
          , details).commit();

In stead of directly invoking the constructor, it's probably easier to use a static method that plugs the arguments into the fragment for you. Such a method is often called newInstance in the examples given by Google. There actually is a newInstance method in DetailsFragment, so I'm unsure why it isn't used in the snippet above...

Anyways, all extras provided as argument upon creating the fragment, will be available by calling getArguments(). Since this returns a Bundle, its usage is similar to that of the extras in an Activity.

public static class DetailsFragment extends Fragment {
     * Create a new instance of DetailsFragment, initialized to
     * show the text at 'index'.
    public static DetailsFragment newInstance(int index) {
        DetailsFragment f = new DetailsFragment();

        // Supply index input as an argument.
        Bundle args = new Bundle();
        args.putInt("index", index);

        return f;

    public int getShownIndex() {
        return getArguments().getInt("index", 0);

    // (other stuff omitted)


How to convert FileInputStream to InputStream?

InputStream is;

try {
    is = new FileInputStream("c://filename");

} catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
} catch (IOException e) {
    // TODO Auto-generated catch block

return is;

htaccess redirect to https://www

I used the below code from this website, it works great

RewriteEngine On_x000D_
RewriteCond %{SERVER_PORT} 80_x000D_
RewriteRule ^(.*)$$1 [R,L]

Hope it helps

Making view resize to its parent when added with addSubview

Tested in Xcode 9.4, Swift 4 Another way to solve this issue is , You can add

override func layoutSubviews() {
        self.frame = (self.superview?.bounds)!

in subview class.

Angular.js directive dynamic templateURL

I have an example about this.

<!DOCTYPE html>
<html ng-app="app">

    <link rel="stylesheet" href="">

    <div class="container-fluid body-content" ng-controller="formView">
        <div class="row">
            <div class="col-md-12">
                <h4>Register Form</h4>
                <form class="form-horizontal" ng-submit="" name="f" novalidate>
                    <div ng-repeat="item in elements" class="form-group">
                        <element type="{{item.Type}}" model="item"></element>
                    <input ng-show="f.$valid" type="submit" id="submit" value="Submit" class="" />
    <script src=""></script>
    <script src=""></script>
    <script src=""></script>
    <script src="app.js"></script>


angular.module('app', [])
    .controller('formView', function ($scope) {
        $scope.elements = [{
            "PlaceHolder":"Place Holder Text",
            "PlaceHolder":"Place Holder Text",
    .directive('element', function () {
        return {
            restrict: 'E',
            link: function (scope, element, attrs) {
                scope.contentUrl = attrs.type + '.html';
                attrs.$observe("ver", function (v) {
                    scope.contentUrl = v + '.html';
            template: '<div ng-include="contentUrl"></div>'

Google Maps API Multiple Markers with Infowindows

function setMarkers(map,locations){

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

 var loan = locations[i][0];
 var lat = locations[i][1];
 var long = locations[i][2];
 var add =  locations[i][3];

 latlngset = new google.maps.LatLng(lat, long);

 var marker = new google.maps.Marker({  
          map: map, title: loan , position: latlngset  

 marker.content = "<h3>Loan Number: " + loan +  '</h3>' + "Address: " + add;,'click', function(map,marker){



Then move var infowindow = new google.maps.InfoWindow() to the initialize() function:

function initialize() {

    var myOptions = {
      center: new google.maps.LatLng(33.890542, 151.274856),
      zoom: 8,
      mapTypeId: google.maps.MapTypeId.ROADMAP

    var map = new google.maps.Map(document.getElementById("default"),
    map.infowindow = new google.maps.InfoWindow();



how to send an array in url request

Separate with commas:






Either way, your method signature needs to be:

@RequestMapping(value = "/GetJson", method = RequestMethod.GET) 
public void getJson(@RequestParam("name") String[] ticker, @RequestParam("startDate") String startDate, @RequestParam("endDate") String endDate) {
   //code to get results from db for those params.

Comparison of C++ unit test frameworks

See this question for some discussion.

They recommend the articles: Exploring the C++ Unit Testing Framework Jungle, By Noel Llopis. And the more recent: C++ Test Unit Frameworks

I have not found an article that compares googletest to the other frameworks yet.

Easy way to make a confirmation dialog in Angular?

You could use sweetalert:

npm install sweetalert --save

Then, simply import it into your application:

import swal from 'sweetalert';

If you pass two arguments, the first one will be the modal's title, and the second one its text.

swal("Here's the title!", "...and here's the text!");

How does Java handle integer underflows and overflows and how would you check for it?

Having just kinda run into this problem myself, here's my solution (for both multiplication and addition):

static boolean wouldOverflowOccurwhenMultiplying(int a, int b) {
    // If either a or b are Integer.MIN_VALUE, then multiplying by anything other than 0 or 1 will result in overflow
    if (a == 0 || b == 0) {
        return false;
    } else if (a > 0 && b > 0) { // both positive, non zero
        return a > Integer.MAX_VALUE / b;
    } else if (b < 0 && a < 0) { // both negative, non zero
        return a < Integer.MAX_VALUE / b;
    } else { // exactly one of a,b is negative and one is positive, neither are zero
        if (b > 0) { // this last if statements protects against Integer.MIN_VALUE / -1, which in itself causes overflow.
            return a < Integer.MIN_VALUE / b;
        } else { // a > 0
            return b < Integer.MIN_VALUE / a;

boolean wouldOverflowOccurWhenAdding(int a, int b) {
    if (a > 0 && b > 0) {
        return a > Integer.MAX_VALUE - b;
    } else if (a < 0 && b < 0) {
        return a < Integer.MIN_VALUE - b;
    return false;

feel free to correct if wrong or if can be simplified. I've done some testing with the multiplication method, mostly edge cases, but it could still be wrong.

How to center the elements in ConstraintLayout

you can use layout_constraintCircle for center view inside ConstraintLayout.


with constraintCircle to parent and zero radius you can make your view be center of parent.

How to declare a Fixed length Array in TypeScript

Actually, You can achieve this with current typescript:

type Grow<T, A extends Array<T>> = ((x: T, ...xs: A) => void) extends ((...a: infer X) => void) ? X : never;
type GrowToSize<T, A extends Array<T>, N extends number> = { 0: A, 1: GrowToSize<T, Grow<T, A>, N> }[A['length'] extends N ? 0 : 1];

export type FixedArray<T, N extends number> = GrowToSize<T, [], N>;


// OK
const fixedArr3: FixedArray<string, 3> = ['a', 'b', 'c'];

// Error:
// Type '[string, string, string]' is not assignable to type '[string, string]'.
//   Types of property 'length' are incompatible.
//     Type '3' is not assignable to type '2'.ts(2322)
const fixedArr2: FixedArray<string, 2> = ['a', 'b', 'c'];

// Error:
// Property '3' is missing in type '[string, string, string]' but required in type 
// '[string, string, string, string]'.ts(2741)
const fixedArr4: FixedArray<string, 4> = ['a', 'b', 'c'];

EDIT (after a long time)

This should handle bigger sizes (as basically it grows array exponentially until we get to closest power of two):

type Shift<A extends Array<any>> = ((...args: A) => void) extends ((...args: [A[0], ...infer R]) => void) ? R : never;

type GrowExpRev<A extends Array<any>, N extends number, P extends Array<Array<any>>> = A['length'] extends N ? A : {
  0: GrowExpRev<[...A, ...P[0]], N, P>,
  1: GrowExpRev<A, N, Shift<P>>
}[[...A, ...P[0]][N] extends undefined ? 0 : 1];

type GrowExp<A extends Array<any>, N extends number, P extends Array<Array<any>>> = A['length'] extends N ? A : {
  0: GrowExp<[...A, ...A], N, [A, ...P]>,
  1: GrowExpRev<A, N, P>
}[[...A, ...A][N] extends undefined ? 0 : 1];

export type FixedSizeArray<T, N extends number> = N extends 0 ? [] : N extends 1 ? [T] : GrowExp<[T, T], N, [[T]]>;

One-liner if statements, how to convert this if-else-statement

If expression returns a boolean, you can just return the result of it.


 return (a > b)

Why does Boolean.ToString output "True" and not "true"

I know the reason why it is the way it is has already been addressed, but when it comes to "custom" boolean formatting, I've got two extension methods that I can't live without anymore :-)

public static class BoolExtensions
    public static string ToString(this bool? v, string trueString, string falseString, string nullString="Undefined") {
        return v == null ? nullString : v.Value ? trueString : falseString;
    public static string ToString(this bool v, string trueString, string falseString) {
        return ToString(v, trueString, falseString, null);

Usage is trivial. The following converts various bool values to their Portuguese representations:

string verdadeiro = true.ToString("verdadeiro", "falso");
string falso = false.ToString("verdadeiro", "falso");
bool? v = null;
string nulo = v.ToString("verdadeiro", "falso", "nulo");

How to stop/shut down an elasticsearch node?

Stopping the service and killing the daemon are indeed the correct ways to shutdown a node. However, it's not recommended to do so directly if you want to take down a node for maintenance. In fact, if you don't have replicas you will lose data.

When you directly shutdown a node, Elasticsearch will wait for 1m (default time) for it to come back online. If it doesn't, then it will start to allocate the shards from that node to other nodes wasting lots of IO.

A typical approach would be to disable shard allocation temporarily by issuing:

PUT _cluster/settings
  "persistent": {
    "cluster.routing.allocation.enable": "none"

Now, when you take down a node, ES won't try to allocate shard from that node to other nodes and you can perform you maintenance activity and then once the node is up, you can enable shard allocation again:

PUT _cluster/settings
  "persistent": {
    "cluster.routing.allocation.enable": "all"


If you don't have replicas for all your indexes, then performing this type of activity will have downtime on some of the indexes. A cleaner way in this case would be to migrate all the shards to other nodes before taking the node down:

PUT _cluster/settings
  "transient" : {
    "cluster.routing.allocation.exclude._ip" : ""

This will move all shards from to other nodes (will take time depending on the data). Once everything is done, you can kill the node, perform maintenance and get it back online. This is a slower operation and is not required if you have replicas.

(Instead of _ip, _id, _name with wildcards will work just fine.)

More information:

Other answers have explained how to kill a process.

Generating 8-character only UUIDs

You can try RandomStringUtils class from apache.commons:

import org.apache.commons.lang3.RandomStringUtils;

final int SHORT_ID_LENGTH = 8;

// all possible unicode characters
String shortId = RandomStringUtils.random(SHORT_ID_LENGTH);

Please keep in mind, that it will contain all possible characters which is neither URL nor human friendly.

So check out other methods too:

// HEX: 0-9, a-f. For example: 6587fddb, c0f182c1
shortId = RandomStringUtils.random(8, "0123456789abcdef"); 

// a-z, A-Z. For example: eRkgbzeF, MFcWSksx
shortId = RandomStringUtils.randomAlphabetic(8); 

// 0-9. For example: 76091014, 03771122
shortId = RandomStringUtils.randomNumeric(8); 

// a-z, A-Z, 0-9. For example: WRMcpIk7, s57JwCVA
shortId = RandomStringUtils.randomAlphanumeric(8); 

As others said probability of id collision with smaller id can be significant. Check out how birthday problem applies to your case. You can find nice explanation how to calculate approximation in this answer.

Using ListView : How to add a header view?

You simply can't use View as a Header of ListView.

Because the view which is being passed in has to be inflated.

Look at my answer at Android ListView addHeaderView() nullPointerException for predefined Views for more info.


Look at this tutorial Android ListView and ListActivity - Tutorial .

EDIT 2: This link is broken Android ListActivity with a header or footer

Extract a page from a pdf as a jpeg

I use a (maybe) much simpler option of pdf2image:

cd $dir
for f in *.pdf
  if [ -f "${f}" ]; then
    n=$(echo "$f" | cut -f1 -d'.')
    pdftoppm -scale-to 1440 -png $f $conv/$n
    rm $f
    mv  $conv/*.png $dir

This is a small part of a bash script in a loop for the use of a narrow casting device. Checks every 5 seconds on added pdf files (all) and processes them. This is for a demo device, at the end converting will be done at a remote server. Converting to .PNG now, but .JPG is possible too.

This converting, together with transitions on A4 format, displaying a video, two smooth scrolling texts and a logo (with transition in three versions) sets the Pi3 to allmost 4x 100% cpu-load ;-)

Bootstrap Navbar toggle button not working

Your code looks great, the only thing i see is that you did not include the collapsed class in your button selector. Note: Requires JavaScript plugin If JavaScript is disabled and the viewport is narrow enough that the navbar collapses, it will be impossible to expand the navbar and view the content within the .navbar-collapse.

The responsive navbar requires the collapse plugin to be included in your version of Bootstrap.

<div class="navbar-wrapper">
      <div class="container">

        <nav class="navbar navbar-inverse navbar-static-top">
          <div class="container">
            <div class="navbar-header">
              <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
              <a class="navbar-brand" href="#">Project name</a>
            <div id="navbar" class="navbar-collapse collapse">
              <ul class="nav navbar-nav">
                    <li><a href="">Page 1</a>
                    <li><a href="">Page 2</a>
                    <li><a href="">Page 3</a>



Excel VBA Run-time error '424': Object Required when trying to copy TextBox

The issue is with this line

 xlo.Worksheets(1).Cells(2, 2) = TextBox1.Text

You have the textbox defined at some other location which you are not using here. Excel is unable to find the textbox object in the current sheet while this textbox was defined in xlw.

Hence replace this with

 xlo.Worksheets(1).Cells(2, 2) = worksheets("xlw").TextBox1.Text 

How to automate drag & drop functionality using Selenium WebDriver Java

I would do it like this in Perl using Selenium::Remote::Driver.

my $sel = <>;  #selenium handle
my $from_loc = <fromloc>;
my $to_loc   = <toloc>;

my $from_element = $sel->find_element($from_loc);
my $to_element = $sel->find_element($to_loc);

# Move mouse to from element, drag and drop
$sel->button_down(); # Holds the mouse button on the element
$sel->mouse_move_to_location(element=>$to); # Move mouse to the destination

This should do it!