Programs & Examples On #Sql calc found rows

Postgresql: error "must be owner of relation" when changing a owner object

From the fine manual.

You must own the table to use ALTER TABLE.

Or be a database superuser.

ERROR: must be owner of relation contact

PostgreSQL error messages are usually spot on. This one is spot on.

MySQL SELECT query string matching

You can use regular expressions like this:

SELECT * FROM pet WHERE name REGEXP 'Bob|Smith'; 

How to list files inside a folder with SQL Server

You can use xp_dirtree

It takes three parameters:

Path of a Root Directory, Depth up to which you want to get files and folders and the last one is for showing folders only or both folders and files.

EXAMPLE: EXEC xp_dirtree 'C:\', 2, 1

How do I call a SQL Server stored procedure from PowerShell?

I include invoke-sqlcmd2.ps1 and write-datatable.ps1 from Calls to run SQL commands take the form:
Invoke-sqlcmd2 -ServerInstance "<sql-server>" -Database <DB> -Query "truncate table <table>"
An example of writing the contents of DataTable variables to a SQL table looks like:
$logs = (get-item SQLSERVER:\sql\<server_path>).ReadErrorLog() Write-DataTable -ServerInstance "<sql-server>" -Database "<DB>" -TableName "<table>" -Data $logs
I find these useful when doing SQL Server database-related PowerShell scripts as the resulting scripts are clean and readable.

dispatch_after - GCD in Swift?

Simplest solution in Swift 3.0 & Swift 4.0 & Swift 5.0

func delayWithSeconds(_ seconds: Double, completion: @escaping () -> ()) {
    DispatchQueue.main.asyncAfter(deadline: .now() + seconds) { 


delayWithSeconds(1) {
   //Do something

How to parse float with two decimal places in javascript?

Please use below function if you don't want to round off.

function ConvertToDecimal(num) {
    num = num.toString(); //If it's not already a String
    num = num.slice(0, (num.indexOf(".")) + 3); //With 3 exposing the hundredths place
   alert('M : ' +  Number(num)); //If you need it back as a Number    

What is a good pattern for using a Global Mutex in C#?

A global Mutex is not only to ensure to have only one instance of an application. I personally prefer using Microsoft.VisualBasic to ensure single instance application like described in What is the correct way to create a single-instance WPF application? (Dale Ragan answer)... I found that's easier to pass arguments received on new application startup to the initial single instance application.

But regarding some previous code in this thread, I would prefer to not create a Mutex each time I want to have a lock on it. It could be fine for a single instance application but in other usage it appears to me has overkill.

That's why I suggest this implementation instead:


static MutexGlobal _globalMutex = null;
static MutexGlobal GlobalMutexAccessEMTP
        if (_globalMutex == null)
            _globalMutex = new MutexGlobal();
        return _globalMutex;

using (GlobalMutexAccessEMTP.GetAwaiter())

Mutex Global Wrapper:

using System;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Security.AccessControl;
using System.Security.Principal;
using System.Threading;

namespace HQ.Util.General.Threading
    public class MutexGlobal : IDisposable
        // ************************************************************************
        public string Name { get; private set; }
        internal Mutex Mutex { get; private set; }
        public int DefaultTimeOut { get; set; }
        public Func<int, bool> FuncTimeOutRetry { get; set; }

        // ************************************************************************
        public static MutexGlobal GetApplicationMutex(int defaultTimeOut = Timeout.Infinite)
            return new MutexGlobal(defaultTimeOut, ((GuidAttribute)Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(GuidAttribute), false).GetValue(0)).Value);

        // ************************************************************************
        public MutexGlobal(int defaultTimeOut = Timeout.Infinite, string specificName = null)
                if (string.IsNullOrEmpty(specificName))
                    Name = Guid.NewGuid().ToString();
                    Name = specificName;

                Name = string.Format("Global\\{{{0}}}", Name);

                DefaultTimeOut = defaultTimeOut;

                FuncTimeOutRetry = DefaultFuncTimeOutRetry;

                var allowEveryoneRule = new MutexAccessRule(new SecurityIdentifier(WellKnownSidType.WorldSid, null), MutexRights.FullControl, AccessControlType.Allow);
                var securitySettings = new MutexSecurity();

                Mutex = new Mutex(false, Name, out bool createdNew, securitySettings);

                if (Mutex == null)
                    throw new Exception($"Unable to create mutex: {Name}");
            catch (Exception ex)
                Log.Log.Instance.AddEntry(Log.LogType.LogException, $"Unable to create Mutex: {Name}", ex);

        // ************************************************************************
        /// <summary>
        /// </summary>
        /// <param name="timeOut"></param>
        /// <returns></returns>
        public MutexGlobalAwaiter GetAwaiter(int timeOut)
            return new MutexGlobalAwaiter(this, timeOut);

        // ************************************************************************
        /// <summary>
        /// </summary>
        /// <param name="timeOut"></param>
        /// <returns></returns>
        public MutexGlobalAwaiter GetAwaiter()
            return new MutexGlobalAwaiter(this, DefaultTimeOut);

        // ************************************************************************
        /// <summary>
        /// This method could either throw any user specific exception or return 
        /// true to retry. Otherwise, retruning false will let the thread continue
        /// and you should verify the state of MutexGlobalAwaiter.HasTimedOut to 
        /// take proper action depending on timeout or not. 
        /// </summary>
        /// <param name="timeOutUsed"></param>
        /// <returns></returns>
        private bool DefaultFuncTimeOutRetry(int timeOutUsed)
            // throw new TimeoutException($"Mutex {Name} timed out {timeOutUsed}.");

            Log.Log.Instance.AddEntry(Log.LogType.LogWarning, $"Mutex {Name} timeout: {timeOutUsed}.");
            return true; // retry

        // ************************************************************************
        public void Dispose()
            if (Mutex != null)

        // ************************************************************************



using System;

namespace HQ.Util.General.Threading
    public class MutexGlobalAwaiter : IDisposable
        MutexGlobal _mutexGlobal = null;

        public bool HasTimedOut { get; set; } = false;

        internal MutexGlobalAwaiter(MutexGlobal mutexEx, int timeOut)
            _mutexGlobal = mutexEx;

                HasTimedOut = !_mutexGlobal.Mutex.WaitOne(timeOut, false);
                if (! HasTimedOut) // Signal received
            } while (_mutexGlobal.FuncTimeOutRetry(timeOut));

        #region IDisposable Support
        private bool disposedValue = false; // To detect redundant calls

        protected virtual void Dispose(bool disposing)
            if (!disposedValue)
                if (disposing)

                // TODO: free unmanaged resources (unmanaged objects) and override a finalizer below.
                // TODO: set large fields to null.

                disposedValue = true;
        // TODO: override a finalizer only if Dispose(bool disposing) above has code to free unmanaged resources.
        // ~MutexExAwaiter()
        // {
        //   // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
        //   Dispose(false);
        // }

        // This code added to correctly implement the disposable pattern.
        public void Dispose()
            // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
            // TODO: uncomment the following line if the finalizer is overridden above.
            // GC.SuppressFinalize(this);

How to move table from one tablespace to another in oracle 11g

I tried many scripts but they didn't work for all objects. You can't move clustered objects from one tablespace to another. For that you will have to use expdp, so I will suggest expdp is the best option to move all objects to a different tablespace.

Below is the command:

nohup expdp \"/ as sysdba\" DIRECTORY=test_dir DUMPFILE=users.dmp LOGFILE=users.log TABLESPACES=USERS &

You can check this link for details.

Serving favicon.ico in ASP.NET MVC

I agree with the answer from Chris, but seeing this is a specific ASP.NET MVC question it would be better to use either Razor syntax:

<link rel="icon" href="@Url.Content("~/content/favicon.ico")"/>

Or traditionally

<link rel="icon" href="<%= Url.Content("~/content/favicon.ico") %>"/>

rather than

<link rel="icon" href=""/>

What difference between the DATE, TIME, DATETIME, and TIMESTAMP Types

DATE: It is used for values with a date part but no time part. MySQL retrieves and displays DATE values in YYYY-MM-DD format. The supported range is 1000-01-01 to 9999-12-31.

DATETIME: It is used for values that contain both date and time parts. MySQL retrieves and displays DATETIME values in YYYY-MM-DD HH:MM:SS format. The supported range is 1000-01-01 00:00:00 to 9999-12-31 23:59:59.

TIMESTAMP: It is also used for values that contain both date and time parts, and includes the time zone. TIMESTAMP has a range of 1970-01-01 00:00:01 UTC to 2038-01-19 03:14:07 UTC.

TIME: Its values are in HH:MM:SS format (or HHH:MM:SS format for large hours values). TIME values may range from -838:59:59 to 838:59:59. The hours part may be so large because the TIME type can be used not only to represent a time of day (which must be less than 24 hours), but also elapsed time or a time interval between two events (which may be much greater than 24 hours, or even negative).

Vuex - Computed property "name" was assigned to but it has no setter

It should be like this.

In your Component

computed: {
                nameFromStore: 'name'
        name: {
             return this.nameFromStore
             return newName

In your store

export const store = new Vuex.Store({
             name : "Stackoverflow"
         getters: {
                 name: (state) => {

expected assignment or function call: no-unused-expressions ReactJS

In my case i never put return inside a arrow function so my code is follow

      return  <h1>{myvariable}</h1>
</ProductConsumer> `

Laravel - check if Ajax request

Maybe this helps. You have to refer the @param

         * Display a listing of the resource.
         * @param  Illuminate\Http\Request $request
         * @return Response
        public function index(Request $request)
                return "AJAX";
            return "HTTP";

D3.js: How to get the computed width and height for an arbitrary element?

For SVG elements

Using something like selection.node().getBBox() you get values like

    height: 5, 
    width: 5, 
    y: 50, 
    x: 20

For HTML elements

Use selection.node().getBoundingClientRect()

How to add favicon.ico in ASP.NET site

    <link rel="shortcut icon" href="@Url.Content("~/images/")favicon.ico" type="image/x-icon"/ >

This works for me in MVC4 application favicon image is placed in the images folder and it will traverse from root directory to images and find favicon.ico bingo!

How can I check the current status of the GPS receiver?

get into similar problem while working on my MSc project, it seems that Daye's answer mistakenly reported "no fix" while the device stays in a static location. I've modified the solution just a little bit which seems to work fine for me in a static location. I don't how would it affect the battery as it is not my main concern, but here's how i did it by re-requesting location updates when a fix has timed out.

private class MyGPSListener implements GpsStatus.Listener {
    public void onGpsStatusChanged(int event) {
        switch (event) {
        case GpsStatus.GPS_EVENT_SATELLITE_STATUS:
            if (Global.getInstance().currentGPSLocation != null)
                if((SystemClock.elapsedRealtime() - mLastLocationMillis) < 20000)
                    if (!hasGPSFix) 
                        Log.i("GPS","Fix Acquired");
                    hasGPSFix = true;
                    if (hasGPSFix) 
                        Log.i("GPS","Fix Lost (expired)");
                        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, locationListener);
                    hasGPSFix = false;
        case GpsStatus.GPS_EVENT_FIRST_FIX:
            Log.i("GPS", "First Fix/ Refix");
            hasGPSFix = true;
        case GpsStatus.GPS_EVENT_STARTED:
            Log.i("GPS", "Started!");
        case GpsStatus.GPS_EVENT_STOPPED:
            Log.i("GPS", "Stopped");

How do I remove a single file from the staging area (undo git add)?

If you make changes to many tracked files but only want to stage a few of them, doing a

git add .

isn't always favorable (or recommended)- as it stages all the tracked files (some cases where you want to keep changes only to yourself and don't want to stage them to the remote repository).

nor is it ideal doing a bunch of

git add path/to/file1 path/to/file2

if you have a lot of nested directories (which is the case in most projects) - gets annoying

That's when Git GUI is helpful (probably only time I use it). Just open Git GUI, it shows staged and unstaged file sections. Select the files from the staged section that you want to unstage and press

Ctrl+U (for windows)

to unstage them.

How can I exclude multiple folders using Get-ChildItem -exclude?

I'd do it like this:

Get-ChildItem -Path $folder -r  | 
          ? { $_.PsIsContainer -and $_.FullName -notmatch 'archive' }

How to make a PHP SOAP call using the SoapClient class

I don't know why my web service has the same structure with you but it doesn't need Class for parameter, just is array.

For example: - My WSDL:

<soapenv:Envelope xmlns:soapenv=""
        <ns:createOrder reference="260778">
                <from country="ES" node=””/>
                <to country="ES" node="0299"/>
                <description>Zoethout thee</description>
                <surname>Roldan de Moras</surname>
                    <line1>Calle General Oraá 26</line1>
                    <line2>(4º izda)</line2>
                <email>[email protected]</email>

I var_dump:


Here is result:

  0 => string 'OrderConfirmation createOrder(OrderRequest $createOrder)' (length=56)

  0 => string 'struct OrderRequest {
 Identification identification;
 Delivery delivery;
 Parcel parcel;
 Receiver receiver;
 string reference;
}' (length=130)
  1 => string 'struct Identification {
 string sender;
 string hash;
 string originator;
}' (length=75)
  2 => string 'struct Delivery {
 Node from;
 Node to;
}' (length=41)
  3 => string 'struct Node {
 string country;
 string node;
}' (length=46)
  4 => string 'struct Parcel {
 string description;
 decimal weight;
 string orderNumber;
 date orderDate;
}' (length=93)
  5 => string 'struct Receiver {
 string firstName;
 string surname;
 Address address;
 string email;
 string language;
}' (length=106)
  6 => string 'struct Address {
 string line1;
 string line2;
 string postalCode;
 string city;
 string country;
}' (length=99)
  7 => string 'struct OrderConfirmation {
 string trackingNumber;
 string reference;
}' (length=71)
  8 => string 'struct OrderServiceException {
 string code;
 OrderServiceException faultInfo;
 string message;
}' (length=97)

So in my code:

    $client  = new SoapClient('');

    $params = array(
        'reference' => $orderId,
        'identification' => array(
            'sender' => param('kiala', 'sender_id'),
            'hash' => hash('sha512', $orderId . param('kiala', 'sender_id') . param('kiala', 'password')),
            'originator' => null,
        'delivery' => array(
            'from' => array(
                'country' => 'es',
                'node' => '',
            'to' => array(
                'country' => 'es',
                'node' => '0299'
        'parcel' => array(
            'description' => 'Description',
            'weight' => 0.200,
            'orderNumber' => $orderId,
            'orderDate' => date('Y-m-d')
        'receiver' => array(
            'firstName' => 'Customer First Name',
            'surname' => 'Customer Sur Name',
            'address' => array(
                'line1' => 'Line 1 Adress',
                'line2' => 'Line 2 Adress',
                'postalCode' => 28006,
                'city' => 'Madrid',
                'country' => 'es',
            'email' => '[email protected]',
            'language' => 'es'
    $result = $client->createOrder($params);

but it successfully!

Android WebView style background-color:transparent ignored on android 2.2

At the bottom of this earlier mentioned issue there is an solution. It's a combination of 2 solutions.

webView.setLayerType(WebView.LAYER_TYPE_SOFTWARE, null);

When adding this code to the WebViewer after loading the url, it works (API 11+).

It even works when hardeware acceleration is ON

How to avoid soft keyboard pushing up my layout?

For future readers.

I wanted specific control over this issue, so this is what I did:

From a fragment or activity, hide your other views (that aren't needed while the keyboard is up), then restore them to solve this problem:

rootView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
     public void onGlobalLayout() {
        Rect r = new Rect();
        int heightDiff = rootView.getRootView().getHeight() - (r.bottom -;

        if (heightDiff > 100) { // if more than 100 pixels, its probably a keyboard...
           //ok now we know the keyboard is up...

        } else {
           //ok now we know the keyboard is down...

Maven error: Not authorized, ReasonPhrase:Unauthorized

The problem here was a typo error in the password used, which was not easily identified due to the characters / letters used in the password.

"RuntimeError: Make sure the Graphviz executables are on your system's path" after installing Graphviz 2.38

Using conda install graphviz and conda install python-graphviz to install GraphViz on Windows10 the path needed was C:/ProgramData/Anaconda3/Library/bin/graphviz/ for me. I.e. adding

import os
os.environ["PATH"] += os.pathsep + 'C:/ProgramData/Anaconda3/Library/bin/graphviz/'

solved the issue for me.

'git' is not recognized as an internal or external command

  1. Go to My Computer => Local Disk(C:) => Program Files(x86) => Git => cmd
  2. Right Click the git => Select Properties
  3. Under the location Copy the text eg - C:\Program Files (x86)\Git\cmd
  4. Come back to the Desktop
  5. Right-click My Computer
  6. Select property
  7. Open Advanced
  8. Click Environment Variables
  9. In the System variables Find the Variable call Path
  10. Click the variable
  11. Click the Edit Button
  12. Select the Variable value Text Box .
  13. Go to the edge of the text and put semicolon(;)
  14. Then Right-click and press Paste
  15. Press Ok

How to fill DataTable with SQL Table

The SqlDataReader is a valid data source for the DataTable. As such, all you need to do its this:

public DataTable GetData()
    SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["BarManConnectionString"].ConnectionString);
    string query = "SELECT * FROM [EventOne]";
    SqlCommand cmd = new SqlCommand(query, conn);

    DataTable dt = new DataTable();
    return dt;

Switch to another Git tag

As of Git v2.23.0 (August 2019), git switch is preferred over git checkout when you’re simply switching branches/tags. I’m guessing they did this since git checkout had two functions: for switching branches and for restoring files. So in v2.23.0, they added two new commands, git switch, and git restore, to separate those concerns. I would predict at some point in the future, git checkout will be deprecated.

To switch to a normal branch, use git switch <branch-name>. To switch to a commit-like object, including single commits and tags, use git switch --detach <commitish>, where <commitish> is the tag name or commit number.

The --detach option forces you to recognize that you’re in a mode of “inspection and discardable experiments”. To create a new branch from the commitish you’re switching to, use git switch -c <new-branch> <start-point>.

Move cursor to end of file in vim

I thought the question was "Move cursor to end of file in vim" ?

End-of-file: Esc + G
Begin-of-file Esc + g (or gg if you are already in the command area)

How can I strip HTML tags from a string in ASP.NET?

Go download HTMLAgilityPack, now! ;) Download LInk

This allows you to load and parse HTML. Then you can navigate the DOM and extract the inner values of all attributes. Seriously, it will take you about 10 lines of code at the maximum. It is one of the greatest free .net libraries out there.

Here is a sample:

            string htmlContents = new System.IO.StreamReader(resultsStream,Encoding.UTF8,true).ReadToEnd();

            HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
            if (doc == null) return null;

            string output = "";
            foreach (var node in doc.DocumentNode.ChildNodes)
                output += node.InnerText;

XPath:: Get following Sibling

You can go for identifying a list of elements with xPath:

//td[text() = ' Color Digest ']/following-sibling::td[1]

This will give you a list of two elements, than you can use the 2nd element as your intended one. For example:

List<WebElement> elements = driver.findElements(By.xpath("//td[text() = ' Color Digest ']/following-sibling::td[1]"))

Now, you can use the 2nd element as your intended element, which is elements.get(1)

How to check if mysql database exists

Rails Code:

ruby-1.9.2-p290 :099 > ActiveRecord::Base.connection.execute("USE INFORMATION_SCHEMA")

ruby-1.9.2-p290 :099 > ActiveRecord::Base.connection.execute("SELECT SCHEMA_NAME FROM         INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = 'entos_development'").to_a
=> [["entos_development"]] 
ruby-1.9.2-p290 :100 > ActiveRecord::Base.connection.execute("SELECT SCHEMA_NAME FROM              INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = 'entos_development1'").to_a
=> []

=> entos_development exist , entos_development1 not exist

How to Sort a List<T> by a property in the object

To do this without LINQ on .Net2.0:

List<Order> objListOrder = GetOrderList();
    delegate(Order p1, Order p2)
        return p1.OrderDate.CompareTo(p2.OrderDate);

If you're on .Net3.0, then LukeH's answer is what you're after.

To sort on multiple properties, you can still do it within a delegate. For example:

    delegate(Order p1, Order p2)
        int compareDate = p1.Date.CompareTo(p2.Date);
        if (compareDate == 0)
            return p2.OrderID.CompareTo(p1.OrderID);
        return compareDate;

This would give you ascending dates with descending orderIds.

However, I wouldn't recommend sticking delegates as it will mean lots of places without code re-use. You should implement an IComparer and just pass that through to your Sort method. See here.

public class MyOrderingClass : IComparer<Order>
    public int Compare(Order x, Order y)
        int compareDate = x.Date.CompareTo(y.Date);
        if (compareDate == 0)
            return x.OrderID.CompareTo(y.OrderID);
        return compareDate;

And then to use this IComparer class, just instantiate it and pass it to your Sort method:

IComparer<Order> comparer = new MyOrderingClass();

List<T> OrderBy Alphabetical Order

This is a generic sorter. Called with the switch below.

dvm.PagePermissions is a property on my ViewModel of type List T in this case T is a EF6 model class called page_permission.

dvm.UserNameSortDir is a string property on the viewmodel that holds the next sort direction. The one that is actaully used in the view.

switch (sortColumn)
    case "user_name":
        dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.user_name, ref sortDir);
        dvm.UserNameSortDir = sortDir;
    case "role_name":
        dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.role_name, ref sortDir);
        dvm.RoleNameSortDir = sortDir;
    case "page_name":
        dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.page_name, ref sortDir);
        dvm.PageNameSortDir = sortDir;

public List<T> Sort<T,TKey>(List<T> list, Func<T, TKey> sorter, ref string direction)
        if (direction == "asc")
            list = list.OrderBy(sorter).ToList();
            direction = "desc";
            list = list.OrderByDescending(sorter).ToList();
            direction = "asc";
        return list;

RequestDispatcher.forward() vs HttpServletResponse.sendRedirect()

requestDispatcher - forward() method

  1. When we use the forward method, the request is transferred to another resource within the same server for further processing.

  2. In the case of forward, the web container handles all processing internally and the client or browser is not involved.

  3. When forward is called on the requestDispatcherobject, we pass the request and response objects, so our old request object is present on the new resource which is going to process our request.

  4. Visually, we are not able to see the forwarded address, it is transparent.

  5. Using the forward() method is faster than sendRedirect.

  6. When we redirect using forward, and we want to use the same data in a new resource, we can use request.setAttribute() as we have a request object available.


  1. In case of sendRedirect, the request is transferred to another resource, to a different domain, or to a different server for further processing.

  2. When you use sendRedirect, the container transfers the request to the client or browser, so the URL given inside the sendRedirect method is visible as a new request to the client.

  3. In case of sendRedirect call, the old request and response objects are lost because it’s treated as new request by the browser.

  4. In the address bar, we are able to see the new redirected address. It’s not transparent.

  5. sendRedirect is slower because one extra round trip is required, because a completely new request is created and the old request object is lost. Two browser request are required.

  6. But in sendRedirect, if we want to use the same data for a new resource we have to store the data in session or pass along with the URL.

Which one is good?

Its depends upon the scenario for which method is more useful.

If you want control is transfer to new server or context, and it is treated as completely new task, then we go for sendRedirect. Generally, a forward should be used if the operation can be safely repeated upon a browser reload of the web page and will not affect the result.


Why is __init__() always called after __new__()?

Referring to this doc:

When subclassing immutable built-in types like numbers and strings, and occasionally in other situations, the static method new comes in handy. new is the first step in instance construction, invoked before init.

The new method is called with the class as its first argument; its responsibility is to return a new instance of that class.

Compare this to init: init is called with an instance as its first argument, and it doesn't return anything; its responsibility is to initialize the instance.

There are situations where a new instance is created without calling init (for example when the instance is loaded from a pickle). There is no way to create a new instance without calling new (although in some cases you can get away with calling a base class's new).

Regarding what you wish to achieve, there also in same doc info about Singleton pattern

class Singleton(object):
        def __new__(cls, *args, **kwds):
            it = cls.__dict__.get("__it__")
            if it is not None:
                return it
            cls.__it__ = it = object.__new__(cls)
            it.init(*args, **kwds)
            return it
        def init(self, *args, **kwds):

you may also use this implementation from PEP 318, using a decorator

def singleton(cls):
    instances = {}
    def getinstance():
        if cls not in instances:
            instances[cls] = cls()
        return instances[cls]
    return getinstance

class MyClass:

What is the difference between MacVim and regular Vim?

The one reason I have which made switching to MacVim worth it: Yank uses the system clipboard.

I can finally copy paste between MacVim on my terminal and the rest of my applications.

Display QImage with QtGui

Simple, but complete example showing how to display QImage might look like this:

#include <QtGui/QApplication>
#include <QLabel>

int main(int argc, char *argv[])
    QApplication a(argc, argv);

    QImage myImage;

    QLabel myLabel;

    return a.exec();

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(), 

How to get a reference to an iframe's window object inside iframe's onload handler created from parent window

You're declaring everything in the parent page. So the references to window and document are to the parent page's. If you want to do stuff to the iframe's, use iframe || iframe.contentWindow to access its window, and iframe.contentDocument || iframe.contentWindow.document to access its document.

There's a word for what's happening, possibly "lexical scope": What is lexical scope?

The only context of a scope is this. And in your example, the owner of the method is doc, which is the iframe's document. Other than that, anything that's accessed in this function that uses known objects are the parent's (if not declared in the function). It would be a different story if the function were declared in a different place, but it's declared in the parent page.

This is how I would write it:

(function () {
  var dom, win, doc, where, iframe;

  iframe = document.createElement('iframe');
  iframe.src = "javascript:false";

  where = document.getElementsByTagName('script')[0];
  where.parentNode.insertBefore(iframe, where);

  win = iframe.contentWindow || iframe;
  doc = iframe.contentDocument || iframe.contentWindow.document;;
  doc._l = (function (w, d) {
    return function () {
      w.vanishing_global = new Date().getTime();

      var js = d.createElement("script");
      js.src = 'test-vanishing-global.js?' + w.vanishing_global; = "foobar";
      d.foobar = "foobar:" + Math.random();
      d.foobar = "barfoo:" + Math.random();
  })(win, doc);
  doc.write('<body onload="document._l();"></body>');

The aliasing of win and doc as w and d aren't necessary, it just might make it less confusing because of the misunderstanding of scopes. This way, they are parameters and you have to reference them to access the iframe's stuff. If you want to access the parent's, you still use window and document.

I'm not sure what the implications are of adding methods to a document (doc in this case), but it might make more sense to set the _l method on win. That way, things can be run without a prefix...such as <body onload="_l();"></body>

How to create a DB for MongoDB container on start up?

The official mongo image has merged a PR to include the functionality to databases and admin users at startup.

The database initialisation will run scripts in /docker-entrypoint-initdb.d/ when there is nothing populated in the /data/db directory.

Database Initialisation

The mongo container image provides the /docker-entrypoint-initdb.d/ path to deploy custom .js or .sh setup scripts that will be run once on database initialisation. .js scripts will be run against test by default or MONGO_INITDB_DATABASE if defined in the environment.

COPY /docker-entrypoint-initdb.d/


COPY mysetup.js /docker-entrypoint-initdb.d/

A simple initialisation mongo shell javascript file that demonstrates setting up the container collection with data, logging and how to exit with an error (for result checking).

let error = true

let res = [
  db.container.createIndex({ myfield: 1 }, { unique: true }),
  db.container.createIndex({ thatfield: 1 }),
  db.container.createIndex({ thatfield: 1 }),
  db.container.insert({ myfield: 'hello', thatfield: 'testing' }),
  db.container.insert({ myfield: 'hello2', thatfield: 'testing' }),
  db.container.insert({ myfield: 'hello3', thatfield: 'testing' }),
  db.container.insert({ myfield: 'hello3', thatfield: 'testing' })


if (error) {
  print('Error, exiting')

Admin User Setup

The environment variables to control "root" user setup are



docker run -d \

or Dockerfile


You don't need to use --auth on the command line as the docker script adds this in when it detects the environment variables exist.

A keyboard shortcut to comment/uncomment the select text in Android Studio

To comment/uncomment one line, use: Ctrl + /.

To comment/uncomment a block, use: Ctrl + Shift + /.

Android: Quit application when press back button

Instead of finish() call super.onBackPressed()

How can I execute a PHP function in a form action?

require_once ( 'username.php' );

if (isset($_POST['textfield'])) {
    echo username();

echo '
<form name="form1" method="post" action="">
      <input type="text" name="textfield" id="textfield">
      <input type="submit" name="button" id="button" value="Submit">

You need to run the function in the page the form is sent to.

PHP Warning Permission denied (13) on session_start()

I have had this issue before, you need more than the standard 755 or 644 permission to store the $_SESSION information. You need to be able to write to that file as that is how it remembers.

Eclipse C++: Symbol 'std' could not be resolved

I was having this problem using Eclipse Neon on Kubuntu with a 16.04 kernel, I had to change my #include <stdlib.h> to #include <cstdlib> this made the std namespace "visible" to Eclipse and removed the error.

Changing Tint / Background color of UITabBar

for me its very simple to change the color of Tabbar like :-

[self.TabBarController.tabBar setTintColor:[UIColor colorWithRed:0.1294 green:0.5686 blue:0.8353 alpha:1.0]];

[self.TabBarController.tabBar setTintColor:[UIColor "YOUR COLOR"];

Try this!!!

Expanding a parent <div> to the height of its children

Using something like self-clearing div is perfect for a situation like this. Then you'll just use a class on the parent... like:

<div id="parent" class="clearfix">

What is .htaccess file?

.htaccess file create in directory /var/www/html/.htaccess

<IfModule mod_rewrite.c>

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [QSA,L]

What does a just-in-time (JIT) compiler do?

You have code that is compliled into some IL (intermediate language). When you run your program, the computer doesn't understand this code. It only understands native code. So the JIT compiler compiles your IL into native code on the fly. It does this at the method level.

What are the best use cases for Akka framework

I have used it so far in two real projects very successfully. both are in the near real-time traffic information field (traffic as in cars on highways), distributed over several nodes, integrating messages between several parties, reliable backend systems. I'm not at liberty to give specifics on clients yet, when I do get the OK maybe it can be added as a reference.

Akka has really pulled through on those projects, even though we started when it was on version 0.7. (we are using scala by the way)

One of the big advantages is the ease at which you can compose a system out of actors and messages with almost no boilerplating, it scales extremely well without all the complexities of hand-rolled threading and you get asynchronous message passing between objects almost for free.

It is very good in modeling any type of asynchronous message handling. I would prefer to write any type of (web) services system in this style than any other style. (Have you ever tried to write an asynchronous web service (server side) with JAX-WS? that's a lot of plumbing). So I would say any system that does not want to hang on one of its components because everything is implicitly called using synchronous methods, and that one component is locking on something. It is very stable and the let-it-crash + supervisor solution to failure really works well. Everything is easy to setup programmatically and not hard to unit test.

Then there are the excellent add-on modules. The Camel module really plugs in well into Akka and enables such easy development of asynchronous services with configurable endpoints.

I'm very happy with the framework and it is becoming a defacto standard for the connected systems that we build.

How do you programmatically set an attribute?

Usually, we define classes for this.

class XClass( object ):
   def __init__( self ):
       self.myAttr= None

x= XClass()
x.myAttr= 'magic'

However, you can, to an extent, do this with the setattr and getattr built-in functions. However, they don't work on instances of object directly.

>>> a= object()
>>> setattr( a, 'hi', 'mom' )
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'object' object has no attribute 'hi'

They do, however, work on all kinds of simple classes.

class YClass( object ):

y= YClass()
setattr( y, 'myAttr', 'magic' )

How to remove last n characters from a string in Bash?

You can do like this:


v="some string.rtf"


echo "$v --> $v2"

How to get current time and date in Android

For those who might rather prefer a customized format, you can use:

DateFormat df = new SimpleDateFormat("EEE, d MMM yyyy, HH:mm");
String date = df.format(Calendar.getInstance().getTime());

Whereas you can have DateFormat patterns such as:

"yyyy.MM.dd G 'at' HH:mm:ss z" ---- 2001.07.04 AD at 12:08:56 PDT
"hh 'o''clock' a, zzzz" ----------- 12 o'clock PM, Pacific Daylight Time
"EEE, d MMM yyyy HH:mm:ss Z"------- Wed, 4 Jul 2001 12:08:56 -0700
"yyyy-MM-dd'T'HH:mm:ss.SSSZ"------- 2001-07-04T12:08:56.235-0700
"yyMMddHHmmssZ"-------------------- 010704120856-0700
"K:mm a, z" ----------------------- 0:08 PM, PDT
"h:mm a" -------------------------- 12:08 PM
"EEE, MMM d, ''yy" ---------------- Wed, Jul 4, '01

Pass command parameter to method in ViewModel in WPF?

If you are that particular to pass elements to viewmodel You can use

 CommandParameter="{Binding ElementName=ManualParcelScanScreen}"

Understanding The Modulus Operator %

modulus is remainders system.

So 7 % 5 = 2.

5 % 7 = 5

3 % 7 = 3

2 % 7 = 2

1 % 7 = 1

When used inside a function to determine the array index. Is it safe programming ? That is a different question. I guess.

grep --ignore-case --only

I'd suggest that the -i means it does match "ABC", but the difference is in the output. -i doesn't manipulate the input, so it won't change "ABC" to "abc" because you specified "abc" as the pattern. -o says it only shows the part of the output that matches the pattern specified, it doesn't say about matching input.

The output of echo "ABC" | grep -i abc is ABC, the -o shows output matching "abc" so nothing shows:

Naos:~ mattlacey$ echo "ABC" | grep -i abc | grep -o abc
Naos:~ mattlacey$ echo "ABC" | grep -i abc | grep -o ABC

What is the maximum length of a valid email address?

The other answers muddy the water a bit. Simple answer: 254 total chars in our control for email 256 are for the ENTIRE email address, which includes implied "<" at the beginning, and ">" at the end. Therefore, 254 are left over for our use.

VNC viewer with multiple monitors

RealVNC 5.0.x now offers a VNCViewer that will do dual displays on Windows without having to buy a license. (Licensing now covers the SERVER portion of their tools).

HTML select drop-down with an input field

You can use input text with "list" attribute, which refers to the datalist of values.

<input type="text" name="city" list="cityname">_x000D_
    <datalist id="cityname">_x000D_
      <option value="Boston">_x000D_
      <option value="Cambridge">_x000D_

This creates a free text input field that also has a drop-down to select predefined choices. Attribution for example and more information:

How to get the row number from a datatable?


int i = Convert.ToInt32(dt.Rows.Count);

I think it's the shortest, thus the simplest way.

How to animate button in android?


Add it in your root build.gradle at the end of repositories:

allprojects {
repositories {
    maven { url "" }

and then add dependency dependencies { compile 'com.github.varunest:sparkbutton:1.0.5' }



        app:sparkbutton_secondaryColor="@color/secondary_color" />

Java (Optional)

SparkButton button  = new SparkButtonBuilder(context)
            .setPrimaryColor(ContextCompat.getColor(context, R.color.primary_color))
            .setSecondaryColor(ContextCompat.getColor(context, R.color.secondary_color))

Get a list of URLs from a site

Here is a list of sitemap generators (from which obviously you can get the list of URLs from a site):

Web Sitemap Generators

The following are links to tools that generate or maintain files in the XML Sitemaps format, an open standard defined on and supported by the search engines such as Ask, Google, Microsoft Live Search and Yahoo!. Sitemap files generally contain a collection of URLs on a website along with some meta-data for these URLs. The following tools generally generate "web-type" XML Sitemap and URL-list files (some may also support other formats).

Please Note: Google has not tested or verified the features or security of the third party software listed on this site. Please direct any questions regarding the software to the software's author. We hope you enjoy these tools!

Server-side Programs

  • Enarion phpSitemapsNG (PHP)
  • Google Sitemap Generator (Linux/Windows, 32/64bit, open-source)
  • Outil en PHP (French, PHP)
  • Perl Sitemap Generator (Perl)
  • Python Sitemap Generator (Python)
  • Simple Sitemaps (PHP)
  • SiteMap XML Dynamic Sitemap Generator (PHP) $
  • Sitemap generator for OS/2 (REXX-script)
  • XML Sitemap Generator (PHP) $

CMS and Other Plugins:

  • ASP.NET - Sitemaps.Net
  • DotClear (Spanish)
  • DotClear (2)
  • Drupal
  • ECommerce Templates (PHP) $
  • Ecommerce Templates (PHP or ASP) $
  • LifeType
  • MediaWiki Sitemap generator
  • mnoGoSearch
  • OS Commerce
  • phpWebSite
  • Plone
  • RapidWeaver
  • Textpattern
  • vBulletin
  • Wikka Wiki (PHP)
  • WordPress

Downloadable Tools

  • GSiteCrawler (Windows)
  • GWebCrawler & Sitemap Creator (Windows)
  • G-Mapper (Windows)
  • Inspyder Sitemap Creator (Windows) $
  • IntelliMapper (Windows) $
  • Microsys A1 Sitemap Generator (Windows) $
  • Rage Google Sitemap Automator $ (OS-X)
  • Screaming Frog SEO Spider and Sitemap generator (Windows/Mac) $
  • Site Map Pro (Windows) $
  • Sitemap Writer (Windows) $
  • Sitemap Generator by DevIntelligence (Windows)
  • Sorrowmans Sitemap Tools (Windows)
  • TheSiteMapper (Windows) $
  • Vigos Gsitemap (Windows)
  • Visual SEO Studio (Windows)
  • WebDesignPros Sitemap Generator (Java Webstart Application)
  • Weblight (Windows/Mac) $
  • WonderWebWare Sitemap Generator (Windows)

Online Generators/Services

  • Sitemap Generator
  • AutoMapIt
  • Autositemap $
  • Enarion phpSitemapsNG
  • Free Sitemap Generator
  • Sitemap Generator
  • ROR Sitemap Generator
  • ScriptSocket Sitemap Generator
  • SeoUtility Sitemap Generator (Italian)
  • SitemapDoc
  • Sitemapspal
  • SitemapSubmit
  • Smart-IT-Consulting Google Sitemaps XML Validator
  • XML Sitemap Generator
  • XML-Sitemaps Generator

CMS with integrated Sitemap generators

  • Concrete5

Google News Sitemap Generators The following plugins allow publishers to update Google News Sitemap files, a variant of the protocol that we describe in our Help Center. In addition to the normal properties of Sitemap files, Google News Sitemaps allow publishers to describe the types of content they publish, along with specifying levels of access for individual articles. More information about Google News can be found in our Help Center and Help Forums.

  • WordPress Google News plugin

Code Snippets / Libraries

  • ASP script
  • Emacs Lisp script
  • Java library
  • Perl script
  • PHP class
  • PHP generator script

If you believe that a tool should be added or removed for a legitimate reason, please leave a comment in the Webmaster Help Forum.

Using OpenGl with C#?

XNA 2.0 requires a minimum of a shader 1.1 card. While old tech, not everyone has one. Some newer laptops (in our experience Toshiba tablets with Intel graphics) have no shader 1.1 support. XNA simply wont run on these machines.

This is a significant issue for us and we have shifted to Tao and OpenGL. Plus with Tao we have bindings for audio & Lua support.

update one table with data from another

UPDATE table1
`ID` = (SELECT FROM table2 WHERE table1.`name`=table2.`name`)

Convert comma separated string of ints to int array

This has been asked before. .Net has a built-in ConvertAll function for converting between an array of one type to an array of another type. You can combine this with Split to separate the string to an array of strings

Example function:

 static int[] ToIntArray(this string value, char separator)
     return Array.ConvertAll(value.Split(separator), s=>int.Parse(s));

Taken from here

Font is not available to the JVM with Jasper Reports

If you are using maven in your project, you can just add the jasper-fonts dependency to pom.xml:


Installing the missing font on the system may be a working solution but not for me, I didn't want to have to install the missing fonts after each deployment in a new server, instead I opted for embedding the font with the application.


How do I enable the column selection mode in Eclipse?

As RichieHindle pointed out the shortcut for column (block) selection is Alt+Shift+A. The problem I ran into is that the Android SDK on Eclipse uses 3 shortcuts that all start with Alt+Shift+A, so if you type that, you'll be given a choice of continuing with D, S, or R.

To solve this I redefined the column selection as Alt+Shift+A,A (Alt, Shift, A pressed together and then followed by a subsequent A). To do this go to Windows > Preferences then type keys or navigate to General > Keys. Under the Keys enter the filter text of block selection to quickly find the shortcut listing for toggle block selection. Here you can adjust the shortcut for column selection as you wish.

Wait until an HTML5 video loads

You don't really need jQuery for this as there is a Media API that provides you with all you need.

var video = document.getElementById('myVideo');
video.src = 'my_video_' + value + '.ogg';

The Media API also contains a load() method which: "Causes the element to reset and start selecting and loading a new media resource from scratch."

(Ogg isn't the best format to use, as it's only supported by a limited number of browsers. I'd suggest using WebM and MP4 to cover all major browsers - you can use the canPlayType() function to decide on which one to play).

You can then wait for either the loadedmetadata or loadeddata (depending on what you want) events to fire:

video.addEventListener('loadeddata', function() {
   // Video is loaded and can be played
}, false);

pop/remove items out of a python tuple

The best solution is the tuple applied to a list comprehension, but to extract one item this could work:

def pop_tuple(tuple, n): return tuple[:n]+tuple[n+1:], tuple[n]

How to change text color of simple list item

you can use setTextColor(int) method or add style to change text color.

<style name="ReviewScreenKbbViewMoreStyle">
<item name="android:textColor">#2F2E86</item>
<item name="android:textStyle">bold</item>
<item name="android:textSize">10dip</item>

The multi-part identifier could not be bound

In my case the issue turned out to be the alias name I had given to the table. "oa" seems to be not acceptable for SQL Server.

Switch: Multiple values in one case?

There's no way to evaluate multiple values in one 'case'. You could either use an if statement (as others have suggested) or call a method which evaluates the range that the integer belongs to and returns a value which represents that range (such as "minor", "adult", etc.), then evaluate this returned value in the switch statement. Of course, you'd probably still be using an if statement in the custom method.

Does .NET provide an easy way convert bytes to KB, MB, GB, etc.?

As posted above, the recursion is the favorite way, with the help of logarithm.

The following function has 3 arguments : the input, the dimension constraint of the output, that is the third argument.

int ByteReDim(unsigned long ival, int constraint, unsigned long *oval)
    int base = 1 + (int) log10(ival);

    (*oval) = ival;
    if (base > constraint) {
        (*oval) = (*oval) >> 10;
        return(1 + ByteReDim((*oval), constraint, oval));
    } else

Now let's convert 12GB of RAM in several units:

int main(void)
    unsigned long RAM;
    int unit; // index of below symbols array
    char symbol[5] = {'B', 'K', 'M', 'G', 'T'};

    unit = ByteReDim(12884901888, 12, &RAM);
    printf("%lu%c\n", RAM, symbol[unit]); // output is 12884901888B

    unit = ByteReDim(12884901888, 9, &RAM);
    printf("%lu%c\n", RAM, symbol[unit]); // output is 12582912K

    unit = ByteReDim(12884901888, 6, &RAM);
    printf("%lu%c\n", RAM, symbol[unit]); // output is 12288M

    unit = ByteReDim(12884901888, 3, &RAM);
    printf("%lu%c\n", RAM, symbol[unit]); // output is 12G

DSO missing from command line

DSO here means Dynamic Shared Object; since the error message says it's missing from the command line, I guess you have to add it to the command line.

That is, try adding -lpthread to your command line.

Converting year and month ("yyyy-mm" format) to a date?

Since dates correspond to a numeric value and a starting date, you indeed need the day. If you really need your data to be in Date format, you can just fix the day to the first of each month manually by pasting it to the date:

month <- "2009-03"

The Web Application Project [...] is configured to use IIS. The Web server [...] could not be found.

For DNN users my issue was I needed a binding for at port 80. I have multiple installs that run on different ports and VS requires that that particular Url to exist on port 80 (not 86 like mine was).

module.exports vs. export default in Node.js and ES6

The issue is with

  • how ES6 modules are emulated in CommonJS
  • how you import the module

ES6 to CommonJS

At the time of writing this, no environment supports ES6 modules natively. When using them in Node.js you need to use something like Babel to convert the modules to CommonJS. But how exactly does that happen?

Many people consider module.exports = ... to be equivalent to export default ... and ... to be equivalent to export const foo = .... That's not quite true though, or at least not how Babel does it.

ES6 default exports are actually also named exports, except that default is a "reserved" name and there is special syntax support for it. Lets have a look how Babel compiles named and default exports:

// input
export const foo = 42;
export default 21;

// output
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
var foo = = 42;
exports.default = 21; 

Here we can see that the default export becomes a property on the exports object, just like foo.

Import the module

We can import the module in two ways: Either using CommonJS or using ES6 import syntax.

Your issue: I believe you are doing something like:

var bar = require('./input');
new bar();

expecting that bar is assigned the value of the default export. But as we can see in the example above, the default export is assigned to the default property!

So in order to access the default export we actually have to do

var bar = require('./input').default;

If we use ES6 module syntax, namely

import bar from './input';

Babel will transform it to

'use strict';

var _input = require('./input');

var _input2 = _interopRequireDefault(_input);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }


You can see that every access to bar is converted to access .default.

Develop Android app using C#

There are indeed C# compilers for Android available. Even though I prefer developing Android Apps in Java, I can recommend MonoForAndroid. You find more information on

How to deal with page breaks when printing a large HTML table

Expanding from Sinan Ünür solution:

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style type="text/css">
    table { page-break-inside:auto }
    div   { page-break-inside:avoid; } /* This is the key */
    thead { display:table-header-group }
    tfoot { display:table-footer-group }
            <td><div>Long<br />cell<br />should'nt<br />be<br />cut</div></td>
            <td><div>Long<br />cell<br />should'nt<br />be<br />cut</div></td>
        <!-- 500 more rows -->

It seems that page-break-inside:avoid in some browsers is only taken in consideration for block elements, not for cell, table, row neither inline-block.

If you try to display:block the TR tag, and use there page-break-inside:avoid, it works, but messes around with your table layout.

How to modify existing, unpushed commit messages?

If you are using the Git GUI, you can amend the last commit which hasn't been pushed with:

Commit/Amend Last Commit

Entity Framework and SQL Server View

We had the same problem and this is the solution:

To force entity framework to use a column as a primary key, use ISNULL.

To force entity framework not to use a column as a primary key, use NULLIF.

An easy way to apply this is to wrap the select statement of your view in another select.


  ISNULL(MyPrimaryID,-999) MyPrimaryID,
  NULLIF(AnotherProperty,'') AnotherProperty
  FROM ( ... ) AS temp

Passing arrays as url parameter

$array["a"] = "Thusitha";
$array["b"] = "Sumanadasa";
$array["c"] = "Lakmal";
$array["d"] = "Nanayakkara";

$str = serialize($array);
$strenc = urlencode($str);
print $str . "\n";
print $strenc . "\n";

print $str . "\n"; gives a:4:{s:1:"a";s:8:"Thusitha";s:1:"b";s:10:"Sumanadasa";s:1:"c";s:6:"Lakmal";s:1:"d";s:11:"Nanayakkara";} and

print $strenc . "\n"; gives


So if you want to pass this $array through URL to page_no_2.php,


$url ='http://page_no_2.php?data=".$strenc."';

To return back to the original array, it needs to be urldecode(), then unserialize(), like this in page_no_2.php:

    $strenc2= $_GET['data'];
    $arr = unserialize(urldecode($strenc2));


 array(4) {
  string(8) "Thusitha"
  string(10) "Sumanadasa"
  string(6) "Lakmal"
  string(11) "Nanayakkara"

again :D

How to add include path in Qt Creator?

If you are using qmake, the standard Qt build system, just add a line to the .pro file as documented in the qmake Variable Reference:

INCLUDEPATH += <your path>

If you are using your own build system, you create a project by selecting "Import of Makefile-based project". This will create some files in your project directory including a file named <your project name>.includes. In that file, simply list the paths you want to include, one per line. Really all this does is tell Qt Creator where to look for files to index for auto completion. Your own build system will have to handle the include paths in its own way.

As explained in the Qt Creator Manual, <your path> must be an absolute path, but you can avoid OS-, host- or user-specific entries in your .pro file by using $$PWD which refers to the folder that contains your .pro file, e.g.

INCLUDEPATH += $$PWD/code/include

How to set a Javascript object values dynamically?

When you create an object myObj as you have, think of it more like a dictionary. In this case, it has two keys, name, and age.

You can access these dictionaries in two ways:

  • Like an array (e.g. myObj[name]); or
  • Like a property (e.g.; do note that some properties are reserved, so the first method is preferred.

You should be able to access it as a property without any problems. However, to access it as an array, you'll need to treat the key like a string.


Otherwise, javascript will assume that name is a variable, and since you haven't created a variable called name, it won't be able to access the key you're expecting.

MySQL load NULL values from CSV data

(variable1, @variable2, ..) SET variable2 = nullif(@variable2, '' or ' ') >> you can put any condition

How to set input type date's default value to today?

Since Date type only accepts the format "yyyy-MM-dd", you need to format the date value accordingly.

Here is the solution for this,

var d = new Date();
var month = d.getMonth();
var month_actual = month + 1;

if (month_actual < 10) {
  month_actual = "0"+month_actual; 

var day_val = d.getDate();
if (day_val < 10) {
  day_val = "0"+day_val; 

document.getElementById("datepicker_id").value = d.getFullYear()+"-"+ month_actual +"-"+day_val;

How to convert a selection to lowercase or uppercase in Sublime Text

From the Sublime Text docs for Windows/Linux:

Keypress            Command
Ctrl + K, Ctrl + U  Transform to Uppercase
Ctrl + K, Ctrl + L  Transform to Lowercase

and for Mac:

Keypress    Command
cmd + KU    Transform to Uppercase
cmd + KL    Transform to Lowercase

Also note that Ctrl + Shift + p in Windows (? + Shift + p in a Mac) brings up the Command Palette where you can search for these and other commands. It looks like this:

enter image description here

What is Vim recording and how can it be disabled?

As others have said, it's macro recording, and you turn it off with q. Here's a nice article about how-to and why it's useful.

Missing maven .m2 folder

Check the configurations in {M2_HOME}\conf\setting.xml as mentioned in the following link.

Hope this helps.

System.Net.WebException: The remote name could not be resolved:

It's probably caused by a local network connectivity issue (but also a DNS error is possible). Unfortunately HResult is generic, however you can determine the exact issue catching HttpRequestException and then inspecting InnerException: if it's a WebException then you can check the WebException.Status property, for example WebExceptionStatus.NameResolutionFailure should indicate a DNS resolution problem.

It may happen, there isn't much you can do.

What I'd suggest to always wrap that (network related) code in a loop with a try/catch block (as also suggested here for other fallible operations). Handle known exceptions, wait a little (say 1000 msec) and try again (for say 3 times). Only if failed all times then you can quit/report an error to your users. Very raw example like this:

private const int NumberOfRetries = 3;
private const int DelayOnRetry = 1000;

public static async Task<HttpResponseMessage> GetFromUrlAsync(string url) {
    using (var client = new HttpClient()) {
        for (int i=1; i <= NumberOfRetries; ++i) {
            try {
                return await client.GetAsync(url); 
            catch (Exception e) when (i < NumberOfRetries) {
                await Task.Delay(DelayOnRetry);

downloading all the files in a directory with cURL

Oh, I have just the thing you need!

$host = "";
$savePath = "downloadedFiles";
if($check = isFtpUp($host)){

    echo $ip." -is alive<br />";

    $check = trim($check);
    $files = explode("\n",$check);

    foreach($files as $n=>$file){
        $file = trim($file);
        if($file !== "." || $file !== ".."){
            if(!saveFtpFile($file, $host.$file, $savePath)){
                // downloading failed. possible reason: $file is a folder name.
                // echo "Error downloading file.<br />";
                echo "File: ".$file." - saved!<br />";
            // do nothing
    echo $ip." - is down.<br />";

and functions isFtpUp and saveFtpFile are as follows:

function isFtpUp($host){
$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, $host);
curl_setopt($ch, CURLOPT_USERPWD, "anonymous:[email protected]");
curl_setopt($ch, CURLOPT_FTPLISTONLY, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 3);

$result = curl_exec($ch);

return $result;


function saveFtpFile( $targetFile = null, $sourceFile = null, $savePath){

// function settings
$timeout = 60;
$ftpuser = "anonymous";
$ftppassword = "[email protected]";
$savePath = "downloadedFiles"; // should exist!
$curl = curl_init();
$file = @fopen ($savePath.'/'.$targetFile, 'w');

    return false;

curl_setopt($curl, CURLOPT_URL, $sourceFile);
curl_setopt($curl, CURLOPT_USERPWD, $ftpuser.':'.$ftppassword);

// curl settings

// curl_setopt($curl, CURLOPT_FAILONERROR, 1);
// curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_TIMEOUT, $timeout);
curl_setopt($curl, CURLOPT_FILE, $file);

$result = curl_exec($curl);

    return false;


return $result;


it's a php script. save it as a .php file, put it on your webserver, change $ip to address(need not be ip) of ftp server you want to download files from, create a directory named downloadedFiles on the same directory as this file.

minimum double value in C/C++

In C, use

#include <float.h>

const double lowest_double = -DBL_MAX;

In C++pre-11, use

#include <limits>

const double lowest_double = -std::numeric_limits<double>::max();

In C++11 and onwards, use

#include <limits>

constexpr double lowest_double = std::numeric_limits<double>::lowest();

How can I get onclick event on webview in android?

I took a look at this and I found that a WebView doesn't seem to send click events to an OnClickListener. If anyone out there can prove me wrong or tell me why then I'd be interested to hear it.

What I did find is that a WebView will send touch events to an OnTouchListener. It does have its own onTouchEvent method but I only ever seemed to get MotionEvent.ACTION_MOVE using that method.

So given that we can get events on a registered touch event listener, the only problem that remains is how to circumvent whatever action you want to perform for a touch when the user clicks a URL.

This can be achieved with some fancy Handler footwork by sending a delayed message for the touch and then removing those touch messages if the touch was caused by the user clicking a URL.

Here's an example:

public class WebViewClicker extends Activity implements OnTouchListener, Handler.Callback {

private static final int CLICK_ON_WEBVIEW = 1;
private static final int CLICK_ON_URL = 2;

private final Handler handler = new Handler(this);

private WebView webView;
private WebViewClient client;

protected void onCreate(Bundle savedInstanceState) {

    webView = (WebView)findViewById(;

    client = new WebViewClient(){ 
        @Override public boolean shouldOverrideUrlLoading(WebView view, String url) { 
            return false;


public boolean onTouch(View v, MotionEvent event) {
    if (v.getId() == && event.getAction() == MotionEvent.ACTION_DOWN){
        handler.sendEmptyMessageDelayed(CLICK_ON_WEBVIEW, 500);
    return false;

public boolean handleMessage(Message msg) {
    if (msg.what == CLICK_ON_URL){
        return true;
    if (msg.what == CLICK_ON_WEBVIEW){
        Toast.makeText(this, "WebView clicked", Toast.LENGTH_SHORT).show();
        return true;
    return false;

Hope this helps.

How to prevent going back to the previous activity?

paulsm4's answer is the correct one. If in onBackPressed() you just return, it will disable the back button. However, I think a better approach given your use case is to flip the activity logic, i.e. make your home activity the main one, check if the user is signed in there, if not, start the sign in activity. The reason is that if you override the back button in your main activity, most users will be confused when they press back and your app does nothing.

Convert pem key to ssh-rsa format

The following script would obtain the public key certificate in base64-encoded DER format and convert it to an OpenSSH public key file. This code assumes that a 2048-bit RSA key is used and draws a lot from this Ian Boyd's answer. I've explained a bit more how it works in comments to this article in Jenkins wiki.

echo -n "ssh-rsa " >
curl -sfI | grep -i X-Instance-Identity | tr -d \\r | cut -d\  -f2 | base64 -d | dd bs=1 skip=32 count=257 status=none | xxd -p -c257 | sed s/^/00000007\ 7373682d727361\ 00000003\ 010001\ 00000101\ / | xxd -p -r | base64 -w0 >>
echo >>

What is the difference between Session.Abandon() and Session.Clear()

When you Abandon() a Session, you (or rather the user) will get a new SessionId (on the next request). When you Clear() a Session, all stored values are removed, but the SessionId stays intact.

Add querystring parameters to link_to

If you want to keep existing params and not expose yourself to XSS attacks, be sure to clean the params hash, leaving only the params that your app can be sending:

# inline
<%= link_to 'Link', params.slice(:sort).merge(per_page: 20) %>


If you use it in multiple places, clean the params in the controller:

# your_controller.rb
@params = params.slice(:sort, :per_page)

# view
<%= link_to 'Link', @params.merge(per_page: 20) %>

How do I concatenate two lists in Python?

You could simply use the + or += operator as follows:

a = [1, 2, 3]
b = [4, 5, 6]

c = a + b


c = []
a = [1, 2, 3]
b = [4, 5, 6]

c += (a + b)

Also, if you want the values in the merged list to be unique you can do:

c = list(set(a + b))

Using variables inside strings

This functionality is not built-in to C# 5 or below.
Update: C# 6 now supports string interpolation, see newer answers.

The recommended way to do this would be with String.Format:

string name = "Scott";
string output = String.Format("Hello {0}", name);

However, I wrote a small open-source library called SmartFormat that extends String.Format so that it can use named placeholders (via reflection). So, you could do:

string name = "Scott";
string output = Smart.Format("Hello {name}", new{name}); // Results in "Hello Scott".

Hope you like it!

ImageView in circular through xml

This is a relatively old question, but you can just make a circle border in the drawable folder (let's assume the xml file will be called circle_border)

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns=""

    <solid android:color="@android:color/transparent" />

    <!-- If you want a padding -->
    <padding android:top="4dp" android:left="4dp" android:right="4dp" android:bottom="4dp" />

    <!-- If you want the circle border to have a color -->
    <strong android:width="1dp" android:color="#FFFFFF" />


Then you can use it as the background of the ImageView

    <!-- other attributes here -->

Android: how to handle button click

Step 1:Create an XML File:

<?xml version="1.0" encoding="utf-8"?>

        android:text="Click Me" />

Step 2:Create MainActivity:

package com.scancode.acutesoft.telephonymanagerapp;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity implements View.OnClickListener {

    Button btnClickEvent;
    protected void onCreate(Bundle savedInstanceState) {

        btnClickEvent = (Button) findViewById(;


    public void onClick(View v) {
        //Your Logic


What causes a java.lang.StackOverflowError

What is java.lang.StackOverflowError

The error java.lang.StackOverflowError is thrown to indicate that the application’s stack was exhausted, due to deep recursion i.e your program/script recurses too deeply.


The StackOverflowError extends VirtualMachineError class which indicates that the JVM have been or have run out of resources and cannot operate further. The VirtualMachineError which extends the Error class is used to indicate those serious problems that an application should not catch. A method may not declare such errors in its throw clause because these errors are abnormal conditions that was never expected to occur.

An Example

Minimal, Complete, and Verifiable Example :

package demo;

public class StackOverflowErrorExample {

    public static void main(String[] args) 

    public static void recursivePrint(int num) {
        System.out.println("Number: " + num);

        if(num == 0)


Console Output

Number: 1
Number: 2
Number: 8645
Number: 8646
Number: 8647Exception in thread "main" java.lang.StackOverflowError
    at Source)
    at Source)
    at Source)
    at Source)
    at sun.nio.cs.StreamEncoder.writeBytes(Unknown Source)
    at sun.nio.cs.StreamEncoder.implFlushBuffer(Unknown Source)
    at sun.nio.cs.StreamEncoder.flushBuffer(Unknown Source)
    at Source)
    at Source)
    at Source)
    at demo.StackOverflowErrorExample.recursivePrint(
    at demo.StackOverflowErrorExample.recursivePrint(
    at demo.StackOverflowErrorExample.recursivePrint(


When a function call is invoked by a Java Application, a stack frame is allocated on the call stack. The stack frame contains the parameters of the invoked method, its local parameters, and the return address of the method. The return address denotes the execution point from which, the program execution shall continue after the invoked method returns. If there is no space for a new stack frame then, the StackOverflowError is thrown by the Java Virtual Machine (JVM).

The most common case that can possibly exhaust a Java application’s stack is recursion. In recursion, a method invokes itself during its execution. Recursion one of the most powerful general-purpose programming technique, but must be used with caution, in order for the StackOverflowError to be avoided.


how to remove empty strings from list, then remove duplicate values from a list

To simplify Amiram Korach's solution:

dtList.RemoveAll(s => string.IsNullOrWhiteSpace(s))

No need to use Distinct() or ToList()

Get Specific Columns Using “With()” Function in Laravel Eloquent

You can do it like this since Laravel 5.5:


Care for the id field and foreign keys as stated in the docs:

When using this feature, you should always include the id column and any relevant foreign key columns in the list of columns you wish to retrieve.

For example, if the user belongs to a team and has a team_id as a foreign key column, then $post->user->team is empty if you don't specifiy team_id


How to print an exception in Python?

Python 3: logging

Instead of using the basic print() function, the more flexible logging module can be used to log the exception. The logging module offers a lot extra functionality, e.g. logging messages into a given log file, logging messages with timestamps and additional information about where the logging happened. (For more information check out the official documentation.)

Logging an exception can be done with the module-level function logging.exception() like so:

import logging

except BaseException:
    logging.exception("An exception was thrown!")


ERROR:root:An exception was thrown!
Traceback (most recent call last):
  File ".../Desktop/", line 4, in <module>
ZeroDivisionError: division by zero 


  • the function logging.exception() should only be called from an exception handler

  • the logging module should not be used inside a logging handler to avoid a RecursionError (thanks @PrakharPandey)

Alternative log-levels

It's also possible to log the exception with another log-level by using the keyword argument exc_info=True like so:

logging.debug("An exception was thrown!", exc_info=True)"An exception was thrown!", exc_info=True)
logging.warning("An exception was thrown!", exc_info=True)

ITSAppUsesNonExemptEncryption export compliance while internal testing?

Add this key in plist file...Everything will be alright..


Just paste before </dict></plist>

Can you set a border opacity in CSS?

Other answers deal with the technical aspect of the border-opacity issue, while I'd like to present a hack(pure CSS and HTML only). Basically create a container div, having a border div and then the content div.

<div class="container">
  <div class="border-box"></div>
  <div class="content-box"></div>

And then the CSS:(set content border to none, take care of positioning such that border thickness is accounted for)

.container {
  width: 20vw;
  height: 20vw;
  position: relative;
.border-box {
  width: 100%;
  height: 100%;
  border: 5px solid black;
  position: absolute;
  opacity: 0.5;
.content-box {
  width: 100%;
  height: 100%;
  border: none;
  background: green;
  top: 5px;
  left: 5px;
  position: absolute;

Clicking HTML 5 Video element to play, pause video, breaks play button

The simplest form is to use the onclick listener:

<video height="auto" controls="controls" preload="none" onclick="">
 <source type="video/mp4" src="vid.mp4">

No jQuery or complicated Javascript code needed.

Play/Pause can be done with onclick="this.paused ? : this.pause();".

How can I extract substrings from a string in Perl?

You could do something like this:

my $data = <<END;
1) Scheme ID: abc-456-hu5t10 (High priority) *
2) Scheme ID: frt-78f-hj542w (Balanced)
3) Scheme ID: 23f-f974-nm54w (super formula run) *

foreach (split(/\n/,$data)) {
  $_ =~ /Scheme ID: ([a-z0-9-]+)\s+\(([^)]+)\)\s*(\*)?/ || next;
  my ($id,$word,$star) = ($1,$2,$3);
  print "$id $word $star\n";

The key thing is the Regular expression:

Scheme ID: ([a-z0-9-]+)\s+\(([^)]+)\)\s*(\*)?

Which breaks up as follows.

The fixed String "Scheme ID: ":

Scheme ID: 

Followed by one or more of the characters a-z, 0-9 or -. We use the brackets to capture it as $1:


Followed by one or more whitespace characters:


Followed by an opening bracket (which we escape) followed by any number of characters which aren't a close bracket, and then a closing bracket (escaped). We use unescaped brackets to capture the words as $2:


Followed by some spaces any maybe a *, captured as $3:


How to avoid HTTP error 429 (Too Many Requests) python

In many cases, continuing to scrape data from a website even when the server is requesting you not to is unethical. However, in the cases where it isn't, you can utilize a list of public proxies in order to scrape a website with many different IP addresses.

npm global path prefix

Spent a while on this issue, and the PATH switch wasn't helping. My problem was the Homebrew/node/npm bug found here -

If you've already installed node using Homebrew, try ****Note per comments that this might not be safe. It worked for me but could have unintended consequences. It also appears that latest version of Homebrew properly installs npm. So likely I would try brew update, brew doctor, brew upgrade node etc before trying****:

npm update -gf

Or, if you want to install node with Homebrew and have npm work, use:

brew install node --without-npm
curl -L | sh

How to symbolicate crash log Xcode?

Ok I realised that you can do this:

  1. In Xcode > Window > Devices, select a connected iPhone/iPad/etc top left.
  2. View Device Logs
  3. All Logs

You probably have a lot of logs there, and to make it easier to find your imported log later, you could just go ahead and delete all logs at this point... unless they mean money to you. Or unless you know the exact point of time the crash happened - it should be written in the file anyway... I'm lazy so I just delete all old logs (this actually took a while).

  1. Just drag and drop your file into that list. It worked for me.

Passing additional variables from command line to make

If you make a file called Makefile and add a variable like this $(unittest) then you will be able to use this variable inside the Makefile even with wildcards

example :

make unittest=*

I use BOOST_TEST and by giving a wildcard to parameter --run_test=$(unittest) then I will be able to use regular expression to filter out the test I want my Makefile to run

How to define servlet filter order of execution using annotations in WAR

You can indeed not define the filter execution order using @WebFilter annotation. However, to minimize the web.xml usage, it's sufficient to annotate all filters with just a filterName so that you don't need the <filter> definition, but just a <filter-mapping> definition in the desired order.

For example,

public class Filter1 implements Filter {}

public class Filter2 implements Filter {}

with in web.xml just this:


If you'd like to keep the URL pattern in @WebFilter, then you can just do like so,

@WebFilter(filterName="filter1", urlPatterns="/url1/*")
public class Filter1 implements Filter {}

@WebFilter(filterName="filter2", urlPatterns="/url2/*")
public class Filter2 implements Filter {}

but you should still keep the <url-pattern> in web.xml, because it's required as per XSD, although it can be empty:

    <url-pattern />
    <url-pattern />

Regardless of the approach, this all will fail in Tomcat until version 7.0.28 because it chokes on presence of <filter-mapping> without <filter>. See also Using Tomcat, @WebFilter doesn't work with <filter-mapping> inside web.xml

Django request.GET

def search(request):
if 'q' in request.GET.keys():
    message = 'You submitted: %r' % request.GET['q']
    message = 'You submitted nothing!'

return HttpResponse(message)

you can use if ... in too.

Find TODO tags in Eclipse

Is there an easy way to view all methods which contain this comment? Some sort of menu option?

Yes, choose one of the following:

  1. Go to Window ? Show View ? Tasks (Not TaskList). The new view will show up where the "Console" and "Problems" tabs are by default.

  2. As mentioned elsewhere, you can see them next to the scroll bar as little blue rectangles if you have the source file in question open.

  3. If you just want the // TODO Auto-generated method stub messages (rather than all // TODO messages) you should use the search function (Ctrl-F for ones in this file Search ? Java Search ? Search string for the ability to specify this workspace, that file, this project, etc.)

Reversing a string in C

You can actually do something like this:

#include <string.h>

void reverse(char *);

int main(void){
 char name[7] = "walter";
 printf("%s", name);

void reverse(char *s) {
  size_t len = strlen(s);
  char *a = s;
  char *b = &s[(int)len - 1];
  char tmp;
  for (; a < b; ++a, --b) {
    tmp = *a;
    *a = *b;
    *b = tmp;

How can I stop Chrome from going into debug mode?

For anyone that's searching why their chrome debugger is automatically jumping to sources tab on every page load, event though all of the breakpoints/pauses/etc have been disabled.

For me it was the "breakOnLoad": true line in VS Code launch.json config.

Unable to compile class for JSP: The type java.util.Map$Entry cannot be resolved. It is indirectly referenced from required .class files

Because we are running on Ubuntu 12.04 LTS and the latest official supported tomcat7 package is 7.0.26 we are not easily able to update the whole tomcat.

I order to test for with the jdk8, I was able to get resolve this issue by changing some jars against their latest 7.0.* version.

I switched jasper.jar, jasper-el and tomcat-util to the version 7.0.53 and added ecj-4.3.1.jar. That brings the application back online.

BUT... also i changed packaged content with this, so maybe it would be better to download the whole tomcat and use it self installed as messing up packages. So please see this only as a very dirty quickhack or workaround.

How to determine the IP address of a Solaris system

Try using ifconfig -a. Look for "inet", that is your IP address

Can't get value of input type="file"?

@BozidarS: FileAPI is supported quite well nowadays and provides a number of useful options.

var file = document.forms['formName']['inputName'].files[0];
// == "photo.png"
//file.type == "image/png"
//file.size == 300821

HTTP client timeout and server timeout

According to, the pref network.http.connection-retry-timeout controls the amount of time in ms (Milliseconds !) to wait for success on the initial connection before beginning the second one. Setting it to 0 disables the parallel connection.

How to Fill an array from user input C#?

It made a lot more sense to add this as an answer to arin's code than to keep doing it in comments...

1) Consider using decimal instead of double. It's more likely to give the answer the user expects. See and for reasons why. Basically decimal works a lot closer to how humans think about numbers than double does. Double works more like how computers "naturally" think about numbers, which is why it's faster - but that's not relevant here.

2) For user input, it's usually worth using a method which doesn't throw an exception on bad input - e.g. decimal.TryParse and int.TryParse. These return a Boolean value to say whether or not the parse succeeded, and use an out parameter to give the result. If you haven't started learning about out parameters yet, it might be worth ignoring this point for the moment.

3) It's only a little point, but I think it's wise to have braces round all "for"/"if" (etc) bodies, so I'd change this:

for (int counter = 0; counter < 6; counter++)
    Console.WriteLine("{0,5}{1,8}", counter, array[counter]);

to this:

for (int counter = 0; counter < 6; counter++)
    Console.WriteLine("{0,5}{1,8}", counter, array[counter]);

It makes the block clearer, and means you don't accidentally write:

for (int counter = 0; counter < 6; counter++)
    Console.WriteLine("{0,5}{1,8}", counter, array[counter]);
    Console.WriteLine("----"); // This isn't part of the for loop!

4) Your switch statement doesn't have a default case - so if the user types anything other than "yes" or "no" it will just ignore them and quit. You might want to have something like:

bool keepGoing = true;
while (keepGoing)
    switch (answer)
        case "yes":
            Console.WriteLine("please enter the array index you wish to get the value of it");
            int index = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("The Value of the selected index is:");
            keepGoing = false;

        case "no":
            Console.WriteLine("HAVE A NICE DAY SIR");
            keepGoing = false;

            Console.WriteLine("Sorry, I didn't understand that. Please enter yes or no");

5) When you've started learning about LINQ, you might want to come back to this and replace your for loop which sums the input as just:

// Or decimal, of course, if you've made the earlier selected change
double sum = input.Sum();

Again, this is fairly advanced - don't worry about it for now!

JavaScript calculate the day of the year (1 - 366)

A straightforward solution with complete explanation.

var dayOfYear = function(date) {
  const daysInMonth = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
  const [yyyy, mm, dd] = date.split('-').map(Number);

  // Checks if February has 29 days
  const isLeap = (year) => new Date(year, 1, 29).getDate() === 29;

  // If it's a leap year, changes 28 to 29
  if (isLeap(yyyy)) daysInMonth[1] = 29;

  let daysBeforeMonth = 0;
  // Slice the array and exclude the current Month
  for (const i of daysInMonth.slice(0, mm - 1)) {
    daysBeforeMonth += i;

  return daysBeforeMonth + dd;


can you add HTTPS functionality to a python flask web server?

For a quick n' dirty self-signed cert, you can also use flask run --cert adhoc or set the FLASK_RUN_CERT env var.

$ export FLASK_APP=""
$ export FLASK_ENV=development
$ export FLASK_RUN_CERT=adhoc

$ flask run
 * Serving Flask app "" (lazy loading)
 * Environment: development
 * Debug mode: on
 * Running on (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 329-665-000

The adhoc option isn't well documented (for good reason, never do this in production), but it's mentioned in the source code.

There's a thorough explanation of this by Miguel Grinberg at Running Your Flask Application Over HTTPS.

How to change dot size in gnuplot

Use the pointtype and pointsize options, e.g.

plot "./points.dat" using 1:2 pt 7 ps 10  

where pt 7 gives you a filled circle and ps 10 is the size.

See: Plotting data.

Predicate Delegates in C#

Just a delegate that returns a boolean. It is used a lot in filtering lists but can be used wherever you'd like.

List<DateRangeClass>  myList = new List<DateRangeClass<GetSomeDateRangeArrayToPopulate);
myList.FindAll(x => (x.StartTime <= minDateToReturn && x.EndTime >= maxDateToReturn):

Eslint: How to disable "unexpected console statement" in Node.js?

In package.json you will find an eslintConfig line. Your 'rules' line can go in there like this:

  "eslintConfig": {
    "extends": [
    "rules": {
      "no-console": "off"

How SID is different from Service name in Oracle tnsnames.ora

Quote by @DAC

In short: SID = the unique name of your DB, ServiceName = the alias used when connecting

Not strictly true. SID = unique name of the INSTANCE (eg the oracle process running on the machine). Oracle considers the "Database" to be the files.

Service Name = alias to an INSTANCE (or many instances). The main purpose of this is if you are running a cluster, the client can say "connect me to", the DBA can on the fly change the number of instances which are available to requests, or even move to a completely different database without the client needing to change any settings.

How do malloc() and free() work?

OK some answers about malloc were already posted.

The more interesting part is how free works (and in this direction, malloc too can be understood better).

In many malloc/free implementations, free does normally not return the memory to the operating system (or at least only in rare cases). The reason is that you will get gaps in your heap and thus it can happen, that you just finish off your 2 or 4 GB of virtual memory with gaps. This should be avoided, since as soon as the virtual memory is finished, you will be in really big trouble. The other reason is, that the OS can only handle memory chunks that are of a specific size and alignment. To be specific: Normally the OS can only handle blocks that the virtual memory manager can handle (most often multiples of 512 bytes e.g. 4KB).

So returning 40 Bytes to the OS will just not work. So what does free do?

Free will put the memory block in its own free block list. Normally it also tries to meld together adjacent blocks in the address space. The free block list is just a circular list of memory chunks which have some administrative data in the beginning. This is also the reason why managing very small memory elements with the standard malloc/free is not efficient. Every memory chunk needs additional data and with smaller sizes more fragmentation happens.

The free-list is also the first place that malloc looks at when a new chunk of memory is needed. It is scanned before it calls for new memory from the OS. When a chunk is found that is bigger than the needed memory, it is divided into two parts. One is returned to caller, the other is put back into the free list.

There are many different optimizations to this standard behaviour (for example for small chunks of memory). But since malloc and free must be so universal, the standard behaviour is always the fallback when alternatives are not usable. There are also optimizations in handling the free-list — for example storing the chunks in lists sorted by sizes. But all optimizations also have their own limitations.

Why does your code crash:

The reason is that by writing 9 chars (don't forget the trailing null byte) into an area sized for 4 chars, you will probably overwrite the administrative-data stored for another chunk of memory that resides "behind" your chunk of data (since this data is most often stored "in front" of the memory chunks). When free then tries to put your chunk into the free list, it can touch this administrative-data and therefore stumble over an overwritten pointer. This will crash the system.

This is a rather graceful behaviour. I have also seen situations where a runaway pointer somewhere has overwritten data in the memory-free-list and the system did not immediately crash but some subroutines later. Even in a system of medium complexity such problems can be really, really hard to debug! In the one case I was involved, it took us (a larger group of developers) several days to find the reason of the crash -- since it was in a totally different location than the one indicated by the memory dump. It is like a time-bomb. You know, your next "free" or "malloc" will crash, but you don't know why!

Those are some of the worst C/C++ problems, and one reason why pointers can be so problematic.

Multithreading in Bash

Sure, just add & after the command:

read_cfg cfgA &
read_cfg cfgB &
read_cfg cfgC &

all those jobs will then run in the background simultaneously. The optional wait command will then wait for all the jobs to finish.

Each command will run in a separate process, so it's technically not "multithreading", but I believe it solves your problem.

Open an image using URI in Android's default gallery image viewer

Accepted answer was not working for me,

What had worked:

Intent intent = new Intent();
intent.setDataAndType(Uri.parse("file://" + "/sdcard/test.jpg"), "image/*");

Regex to remove all special characters from string?

This should do it:


Basically it matches all non-alphanumeric characters.

How to solve time out in phpmyadmin?

I'm using version 4.0.3 of MAMP along with phpmyadmin. The top of /Applications/MAMP/bin/phpMyAdmin/libraries/config.default.php reads:


Changing the following line in /Applications/MAMP/bin/phpMyAdmin/ and restarting MAMP worked for me.

$cfg['ExecTimeLimit'] = 0;

How to create folder with PHP code?

Purely basic folder creation

<?php mkdir("testing"); ?> <= this, actually creates a folder called "testing".

Basic file creation

$file = fopen("test.txt","w");
echo fwrite($file,"Hello World. Testing!");

Use the a or a+ switch to add/append to file.


This version will create a file and folder at the same time and show it on screen after.


// change the name below for the folder you want
$dir = "new_folder_name";

$file_to_write = 'test.txt';
$content_to_write = "The content";

if( is_dir($dir) === false )

$file = fopen($dir . '/' . $file_to_write,"w");

// a different way to write content into
// fwrite($file,"Hello World.");

fwrite($file, $content_to_write);

// closes the file

// this will show the created file from the created folder on screen
include $dir . '/' . $file_to_write;


Convert double to BigDecimal and set BigDecimal Precision

BigDecimal b = new BigDecimal(c).setScale(2,BigDecimal.ROUND_HALF_UP);

How can I change default dialog button text color in android 5

Using styles.xml (value)

Very Easy solution , change colorPrimary as your choice and it will change color of button text of alert box.

<style name="MyAlertDialogStyle" parent="android:Theme.Material.Dialog.Alert">

        <!-- Used for the buttons -->
        <item name="colorAccent">@android:color/white</item>
        <!-- Used for the title and text -->
        <item name="android:textColorPrimary">@color/black</item>

        <!-- Used for the background -->
        <item name="android:background">#ffffff</item>
        <item name="android:colorPrimary">@color/white</item>
        <item name="android:colorAccent">@color/white</item>
        <item name="android:windowEnterAnimation">@anim/bottom_left_enter</item>

Alternative (Using Java)

            public boolean onJsAlert(WebView view, String url, String message, final JsResult result) {

                AlertDialog dialog = new AlertDialog.Builder(view.getContext(),

                        .setTitle("Royal Frolics")
                        .setPositiveButton("OK", (dialog1, which) -> {
                            //do nothing

                Objects.requireNonNull(dialog.getWindow()).getAttributes().windowAnimations =;
                return true;


How do I find out what version of WordPress is running?

From experience with WordPress 3.8.3:

(1) Login as admin (2) Click on the W menu in the upper left corner (3) Click on menu item "About WordPress".

This will take you to .../wp-admin/about.php

There it will say "Welcome to WordPress 3.8.3"

If statement within Where clause

You can't use IF like that. You can do what you want with AND and OR:

SELECT t.first_name,
  FROM employeetable t
 WHERE ((status_flag = STATUS_ACTIVE   AND t.status = 'A')
     OR (status_flag = STATUS_INACTIVE AND t.status = 'T')
     OR (source_flag = SOURCE_FUNCTION AND t.business_unit = 'production')
     OR (source_flag = SOURCE_USER     AND t.business_unit = 'users'))
   AND t.first_name LIKE firstname
   AND t.last_name  LIKE lastname
   AND t.employid   LIKE employeeid;

Troubleshooting "program does not contain a static 'Main' method" when it clearly does...?

I had this problem and its because I wasnt using the latest version of C# (C# 7.3 as of writing this) and I had to change the below internal access modifier to public.

internal class Program
    public static void Main(string[] args)
        //My Code

or ammend the .csproj to use the latest version of C# (this way meant I could still keep the above class as internal):


How to find length of dictionary values

Let dictionary be :

If you know the key :

else :
val=[len(i) for i in dict.values()]
# for printing length of 1st key value or length of values in keys if all keys have same amount of values.

Type List vs type ArrayList in Java

(3) Collection myCollection = new ArrayList<?>();

I am using this typically. And only if I need List methods, I will use List. Same with ArrayList. You always can switch to more "narrow" interface, but you can't switch to more "wide".

Understanding Bootstrap's clearfix class

When a clearfix is used in a parent container, it automatically wraps around all the child elements.

It is usually used after floating elements to clear the float layout.

When float layout is used, it will horizontally align the child elements. Clearfix clears this behaviour.

Example - Bootstrap Panels

In bootstrap, when the class panel is used, there are 3 child types: panel-header, panel-body, panel-footer. All of which have display:block layout but panel-body has a clearfix pre-applied. panel-body is a main container type whereas panel-header & panel-footer isn't intended to be a container, it is just intended to hold some basic text.

If floating elements are added, the parent container does not get wrapped around those elements because the height of floating elements is not inherited by the parent container.

So for panel-header & panel-footer, clearfix is needed to clear the float layout of elements: Clearfix class gives a visual appearance that the height of the parent container has been increased to accommodate all of its child elements.

 <div class="container">
    <div class="panel panel-default">
        <div class="panel-footer">
            <div class="col-xs-6">
                <input type="button" class="btn btn-primary"   value="Button1">
                <input type="button" class="btn btn-primary"   value="Button2">
                <input type="button" class="btn btn-primary"   value="Button3">

    <div class="panel panel-default">
        <div class="panel-footer">
            <div class="col-xs-6">
                <input type="button" class="btn btn-primary"   value="Button1">
                <input type="button" class="btn btn-primary"   value="Button2">
                <input type="button" class="btn btn-primary"   value="Button3">
            <div class="clearfix"/>

see an example photo here

error: invalid initialization of non-const reference of type ‘int&’ from an rvalue of type ‘int’

References are "hidden pointers" (non-null) to things which can change (lvalues). You cannot define them to a constant. It should be a "variable" thing.


I am thinking of

int &x = y;

as almost equivalent of

int* __px = &y;
#define x (*__px)

where __px is a fresh name, and the #define x works only inside the block containing the declaration of x reference.

When to throw an exception?

It is NOT an exception if the username is not valid or the password is not correct. Those are things you should expect in the normal flow of operation. Exceptions are things that are not part of the normal program operation and are rather rare.

EDIT: I do not like using exceptions because you can not tell if a method throws an exception just by looking at the call. Thats why exceptions should only be used if you can't handle the situation in a decent manner (think "out of memory" or "computer is on fire").

Get the last inserted row ID (with SQL statement)

Assuming a simple table:


We can capture IDENTITY values in a table variable for further consumption.


-- minor change to INSERT statement; add an OUTPUT clause:
  OUTPUT inserted.ID INTO @IDs(ID)


The nice thing about this method is (a) it handles multi-row inserts (SCOPE_IDENTITY() only returns the last value) and (b) it avoids this parallelism bug, which can lead to wrong results, but so far is only fixed in SQL Server 2008 R2 SP1 CU5.

JAXB: how to marshall map into <key>value</key>

Seems like this question is kind of duplicate with another one, where I've collect some marshal/unmarshal solutions into one post. You may check it here: Dynamic tag names with JAXB.

In short:

  1. A container class for @xmlAnyElement should be created
  2. An XmlAdapter can be used in pair with @XmlJavaTypeAdapter to convert between the container class and Map<>;

Create a zip file and download it

I just ran into this problem. For me the issue was with:


It was resulting in a out of memory error.

Allowed memory size of 134217728 bytes exhausted (tried to allocate 292982784 bytes)

I was able to correct the problem by replacing readfile() with the following:

    $handle = fopen($zipPath, "rb");
    while (!feof($handle)){
        echo fread($handle, 8192);

Not sure if this is your same issue or not seeing that your file is only 1.2 MB. Maybe this will help someone else with a similar problem.

What is a vertical tab?

A vertical tab was the opposite of a line feed i.e. it went upwards by one line. It had nothing to do with tab positions. If you want to prove this, try it on an RS232 terminal.

How can I count the occurrences of a list item?

I had this problem today and rolled my own solution before I thought to check SO. This:

dict((i,a.count(i)) for i in a)

is really, really slow for large lists. My solution

def occurDict(items):
    d = {}
    for i in items:
        if i in d:
            d[i] = d[i]+1
            d[i] = 1
return d

is actually a bit faster than the Counter solution, at least for Python 2.7.

What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?

Since 2^N is an integer with only the Nth bit set (1 << N), finding the position (N) of the highest set bit is the integer log base 2 of that integer.

unsigned int v;
unsigned r = 0;

while (v >>= 1) {

This "obvious" algorithm may not be transparent to everyone, but when you realize that the code shifts right by one bit repeatedly until the leftmost bit has been shifted off (note that C treats any non-zero value as true) and returns the number of shifts, it makes perfect sense. It also means that it works even when more than one bit is set — the result is always for the most significant bit.

If you scroll down on that page, there are faster, more complex variations. However, if you know you're dealing with numbers with a lot of leading zeroes, the naive approach may provide acceptable speed, since bit shifting is rather fast in C, and the simple algorithm doesn't require indexing an array.

NOTE: When using 64-bit values, be extremely cautious about using extra-clever algorithms; many of them only work correctly for 32-bit values.

HTTP status code for update and delete?

Here's some status code, which you should know for your kind of knowledge.

1XX Information Responses

  • 100 Continue
  • 101 Switching Protocols
  • 102 Processing
  • 103 Early Hints

2XX Success

  • 200 OK
  • 201 Created
  • 202 Accepted
  • 203 Non-Authoritative Information
  • 204 No Content
  • 205 Reset Content
  • 206 Partial Content
  • 207 Multi-Status
  • 208 Already Reported
  • 226 IM Used

3XX Redirection

  • 300 Multiple Choices
  • 301 Moved Permanently
  • 302 Found
  • 303 See Other
  • 304 Not Modified
  • 305 Use Proxy
  • 306 Switch Proxy
  • 307 Temporary Redirect
  • 308 Permanent Redirect

4XX Client errors

  • 400 Bad Request
  • 401 Unauthorized
  • 402 Payment Required
  • 403 Forbidden
  • 404 Not Found
  • 405 Method Not Allowed
  • 406 Not Acceptable
  • 407 Proxy Authentication Required
  • 408 Request Timeout
  • 409 Conflict
  • 410 Gone
  • 411 Length Required
  • 412 Precondition Failed
  • 413 Payload Too Large
  • 414 URI Too Long
  • 415 Unsupported Media Type
  • 416 Range Not Satisfiable
  • 417 Expectation Failed
  • 418 I'm a teapot
  • 420 Method Failure
  • 421 Misdirected Request
  • 422 Unprocessable Entity
  • 423 Locked
  • 424 Failed Dependency
  • 426 Upgrade Required
  • 428 Precondition Required
  • 429 Too Many Requests
  • 431 Request Header Fields Too Large
  • 451 Unavailable For Legal Reasons

5XX Server errors

  • 500 Internal Server error
  • 501 Not Implemented
  • 502 Bad Gateway
  • 503 Service Unavailable
  • 504 gateway Timeout
  • 505 Http version not supported
  • 506 Varient Also negotiate
  • 507 Insufficient Storage
  • 508 Loop Detected
  • 510 Not Extended
  • 511 Network Authentication Required

Get selected option text with JavaScript

I just copy all "select list", you can see demo from following image.gif link.

see demo now

I love "select/option" css style and javascript tricks...

try it now....

/***javascript code***/
  document.querySelector("#mySelect").addEventListener("click", () => {
    var x = document.querySelector("#mySelect").selectedIndex;
    let optionText = document.getElementsByTagName("option")[x].innerText;
    document.querySelector(".nav-search-label").innerText = optionText;
  .nav-left {
    display: -webkit-box;
    display: -moz-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
    position: static;
    float: none;
  .nav-search-scope {
    display: -webkit-box;
    display: -moz-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
    position: relative;
    float: none;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
  .nav-search-facade {
    position: relative;
    float: left;
    cursor: default;
    overflow: hidden;
    top: 3px;
  .nav-search-label {
    display: block;
    overflow: hidden;
    white-space: nowrap;
    text-overflow: ellipsis;
    color: #555;
    font-size: 12px;
    line-height: 33px;
    margin-right: 21px;
    margin-left: 5px;
    min-width: 19px;
  .nav-icon {
    position: absolute;
    top: 14px;
    right: 8px;
    border-style: solid;
    _border-style: dashed;
    border-width: 4px;
    border-color: transparent;
    border-top: 4px solid #666;
    border-bottom-width: 0;
    width: 0;
    height: 0;
    font-size: 0;
    line-height: 0;
  .nav-search-dropdown {
    position: absolute;
    display: block;
    top: -1px;
    left: 0;
    height: 35px;
    width: auto;
    font-family: inherit;
    outline: 0;
    margin: 0;
    padding: 0;
    cursor: pointer;
    opacity: 0;
    filter: alpha(opacity=0);
    visibility: visible;
    border: 0;
    line-height: 35px;
<!--html code-->
<div class="nav-left">
  <div id="nav-search-dropdown-card">
    <div class="nav-search-scope nav-sprite">
      <div class="nav-search-facade">
        <span class="nav-search-label" style="width: auto">All</span>
        <i class="nav-icon"></i>

        class="nav-search-dropdown searchSelect"
        style="display: block; top: 3px"
        title="Search in"
        <option>All Departments</option>
        <option>Arts &amp; Crafts</option>
        <option>Beauty &amp; Personal Care</option>
        <option>Digital Music</option>
        <option>Kindle Store</option>
        <option>Prime Video</option>
        <option>Women's Fashion</option>
        <option>Men's Fashion</option>
        <option>Girls' Fashion</option>
        <option>Boys' Fashion</option>
        <option>Health &amp; Household</option>
        <option>Home &amp; Kitchen</option>
        <option>Industrial &amp; Scientific</option>
        <option>Movies &amp; TV</option>
        <option>Music, CDs &amp; Vinyl</option>
        <option>Pet Supplies</option>
        <option>Sports &amp; Outdoors</option>
        <option>Tools &amp; Home Improvement</option>
        <option>Toys &amp; Games</option>
        <option>Video Games</option>

Mailto: Body formatting

Forget it; this might work with Outlook or maybe even GMail but you won't be able to get this working properly supporting most other E-mail clients out there (and there's a shitton of 'em).

You're better of using a simple PHP script (check out PHPMailer) or use a hosted solution (Google "email form hosted", "free email form hosting" or something similar)

By the way, you are looking for the term "Percent-encoding" (also called url-encoding and Javascript uses encodeUri/encodeUriComponent (make sure you understand the differences!)). You will need to encode a whole lot more than just newlines.

what's the correct way to send a file from REST web service to client?

Since youre using JSON, I would Base64 Encode it before sending it across the wire.

If the files are large, try to look at BSON, or some other format that is better with binary transfers.

You could also zip the files, if they compress well, before base64 encoding them.

Predicate in Java

You can view the java doc examples or the example of usage of Predicate here

Basically it is used to filter rows in the resultset based on any specific criteria that you may have and return true for those rows that are meeting your criteria:

 // the age column to be between 7 and 10
    AgeFilter filter = new AgeFilter(7, 10, 3);

    // set the filter.

SQL Group By with an Order By

You can get around this limit with the deprecated syntax: ORDER BY 1 DESC

This syntax is not deprecated at all, it's E121-03 from SQL99.

make *** no targets specified and no makefile found. stop

Delete your source tree that was gunzipped or gzipped and extracted to folder and reextract again. Supply your options again

./configure --with-option=/path/etc ...

Then if all libs are present, your make should succeed.

Select row and element in awk

Since awk and perl are closely related...

Perl equivalents of @Dennis's awk solutions:

To print the second line:
perl -ne 'print if $. == 2' file

To print the second field:
perl -lane 'print $F[1]' file

To print the third field of the fifth line:
perl -lane 'print $F[2] if $. == 5' file

Perl equivalent of @Glenn's solution:

Print the j'th field of the i'th line

perl -lanse 'print $F[$j-1] if $. == $i' -- -i=5 -j=3 file

Perl equivalents of @Hai's solutions:

if you are looking for second columns that contains abc:

perl -lane 'print if $F[1] =~ /abc/' foo

... and if you want to print only a particular column:

perl -lane 'print $F[2] if $F[1] =~ /abc/' foo

... and for a particular line number:

perl -lane 'print $F[2] if $F[1] =~ /abc/ && $. == 5' foo

-l removes newlines, and adds them back in when printing
-a autosplits the input line into array @F, using whitespace as the delimiter
-n loop over each line of the input file
-e execute the code within quotes
$F[1] is the second element of the array, since Perl starts at 0
$. is the line number

SQL Server JOIN missing NULL values

The only correct answer is not to join columns with null values. This can lead to unwanted behaviour very quickly.

e.g. isnull(b.colId,''): What happens if you have empty strings in your data? The join maybe duplicate rows which I guess is not intended in this case.

to_string is not a member of std, says g++ (mingw)

For me, ensuring that I had:

#include <iostream>  
using namespace std;

in my file made something like to_string(12345) work.

Set drawable size programmatically

Button button = new Button(this);
Button = (Button) findViewById(;

Use Button.setHeight() or Button.setWeight() and set a value.

How to use pagination on HTML tables?

As far as I can see it on the website of that paginations plugin, the plugin itself doesn't do the actual pagination. The only thing it does is display a row of numbers, and display the correct buttons depending on the page you're on.

However, to actually paginate, you have to write the appropriate Javascript yourself. This should be placed in stead of this Javascript:

function test(pageNumber)

  var page="#page-id-"+pageNumber;


Which is code I'm guessing you've copy-pasted from somewhere but at the moment doesn't really do anything. If you don't know Javascript, going with another library that actually does pagination of a table is something you probably want to do.

Advantages of std::for_each over for loop

You can have the iterator be a call to a function that is performed on each iteration through the loop.

See here:

How to deploy a React App on Apache web server

Ultimately was able to figure it out , i just hope it will help someone like me.
Following is how the web pack config file should look like check the dist dir and output file specified. I was missing the way to specify the path of dist directory

const webpack = require('webpack');
const path = require('path');
var config = {
    entry: './main.js',

    output: {
        path: path.join(__dirname, '/dist'),
        filename: 'index.js',

    devServer: {
        inline: true,
        port: 8080
    resolveLoader: {
        modules: [path.join(__dirname, 'node_modules')]
    module: {
        loaders: [
                test: /\.jsx?$/,
                exclude: /node_modules/,
                loader: 'babel-loader',

                query: {
                    presets: ['es2015', 'react']

module.exports = config;

Then the package json file

  "name": "reactapp",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "webpack --progress",
    "production": "webpack -p --progress"
  "author": "",
  "license": "ISC",
  "dependencies": {
    "react": "^15.4.2",
    "react-dom": "^15.4.2",
    "webpack": "^2.2.1"
  "devDependencies": {
    "babel-core": "^6.0.20",
    "babel-loader": "^6.0.1",
    "babel-preset-es2015": "^6.0.15",
    "babel-preset-react": "^6.0.15",
    "babel-preset-stage-0": "^6.0.15",
    "express": "^4.13.3",
    "webpack": "^1.9.6",
    "webpack-devserver": "0.0.6"

Notice the script section and production section, production section is what gives you the final deployable index.js file ( name can be anything )

Rest fot the things will depend upon your code and components

Execute following sequence of commands

npm install

this should get you all the dependency (node modules)


npm run production

this should get you the final index.js file which will contain all the code bundled

Once done place index.html and index.js files under www/html or the web app root directory and that's all.

Best way to integrate Python and JavaScript?

There's a bridge based on JavaScriptCore (from WebKit), but it's pretty incomplete:

Maven "build path specifies execution environment J2SE-1.5", even though I changed it to 1.7

I was facing the same issue. In pom.xml I have specified maven compiler plugin to pick 1.7 as source and target. Even then when I would import the git project in eclipse it would pick 1.5 as compile version for the project. To be noted that the eclipse has installed runtime set to JDK 1.8

I also checked that none of the .classpath .impl or .project file is checked in git repository.

Solution that worked for me: I simply deleted .classpath files and did a 'maven-update project'. .classpath file was regenerated and it picked up 1.7 as compile version from pom file.

Select the values of one property on all objects of an array in PowerShell

To complement the preexisting, helpful answers with guidance of when to use which approach and a performance comparison.

  • Outside of a pipeline[1], use (PSv3+):

    as demonstrated in rageandqq's answer, which is both syntactically simpler and much faster.

    • Accessing a property at the collection level to get its members' values as an array is called member enumeration and is a PSv3+ feature.

    • Alternatively, in PSv2, use the foreach statement, whose output you can also assign directly to a variable:

      $results = foreach ($obj in $objects) { $obj.Name }

    • If collecting all output from a (pipeline) command in memory first is feasible, you can also combine pipelines with member enumeration; e.g.:

       (Get-ChildItem -File | Where-Object Length -lt 1gb).Name
    • Tradeoffs:

      • Both the input collection and output array must fit into memory as a whole.
      • If the input collection is itself the result of a command (pipeline) (e.g., (Get-ChildItem).Name), that command must first run to completion before the resulting array's elements can be accessed.
  • In a pipeline, in case you must pass the results to another command, notably if the original input doesn't fit into memory as a whole, use:

    $objects | Select-Object -ExpandProperty Name

    • The need for -ExpandProperty is explained in Scott Saad's answer (you need it to get only the property value).
    • You get the usual pipeline benefits of the pipeline's streaming behavior, i.e. one-by-one object processing, which typically produces output right away and keeps memory use constant (unless you ultimately collect the results in memory anyway).
    • Tradeoff:
      • Use of the pipeline is comparatively slow.

For small input collections (arrays), you probably won't notice the difference, and, especially on the command line, sometimes being able to type the command easily is more important.

Here is an easy-to-type alternative, which, however is the slowest approach; it uses simplified ForEach-Object syntax called an operation statement (again, PSv3+): ; e.g., the following PSv3+ solution is easy to append to an existing command:

$objects | % Name      # short for: $objects | ForEach-Object -Process { $_.Name }

The PSv4+ .ForEach() array method, more comprehensively discussed in this article, is yet another, well-performing alternative, but note that it requires collecting all input in memory first, just like member enumeration:

# By property name (string):

# By script block (more flexibility; like ForEach-Object)
$objects.ForEach({ $_.Name })
  • This approach is similar to member enumeration, with the same tradeoffs, except that pipeline logic is not applied; it is marginally slower than member enumeration, though still noticeably faster than the pipeline.

  • For extracting a single property value by name (string argument), this solution is on par with member enumeration (though the latter is syntactically simpler).

  • The script-block variant ({ ... }) allows arbitrary transformations; it is a faster - all-in-memory-at-once - alternative to the pipeline-based ForEach-Object cmdlet (%).

Note: The .ForEach() array method, like its .Where() sibling (the in-memory equivalent of Where-Object), always returns a collection (an instance of [System.Collections.ObjectModel.Collection[psobject]]), even if only one output object is produced.
By contrast, member enumeration, Select-Object, ForEach-Object and Where-Object return a single output object as-is, without wrapping it in a collection (array).

Comparing the performance of the various approaches

Here are sample timings for the various approaches, based on an input collection of 10,000 objects, averaged across 10 runs; the absolute numbers aren't important and vary based on many factors, but it should give you a sense of relative performance (the timings come from a single-core Windows 10 VM:


  • The relative performance varies based on whether the input objects are instances of regular .NET Types (e.g., as output by Get-ChildItem) or [pscustomobject] instances (e.g., as output by Convert-FromCsv).
    The reason is that [pscustomobject] properties are dynamically managed by PowerShell, and it can access them more quickly than the regular properties of a (statically defined) regular .NET type. Both scenarios are covered below.

  • The tests use already-in-memory-in-full collections as input, so as to focus on the pure property extraction performance. With a streaming cmdlet / function call as the input, performance differences will generally be much less pronounced, as the time spent inside that call may account for the majority of the time spent.

  • For brevity, alias % is used for the ForEach-Object cmdlet.

General conclusions, applicable to both regular .NET type and [pscustomobject] input:

  • The member-enumeration ($collection.Name) and foreach ($obj in $collection) solutions are by far the fastest, by a factor of 10 or more faster than the fastest pipeline-based solution.

  • Surprisingly, % Name performs much worse than % { $_.Name } - see this GitHub issue.

  • PowerShell Core consistently outperforms Windows Powershell here.

Timings with regular .NET types:

  • PowerShell Core v7.0.0-preview.3
Factor Command                                       Secs (10-run avg.)
------ -------                                       ------------------
1.00   $objects.Name                                 0.005
1.06   foreach($o in $objects) { $o.Name }           0.005
6.25   $objects.ForEach('Name')                      0.028
10.22  $objects.ForEach({ $_.Name })                 0.046
17.52  $objects | % { $_.Name }                      0.079
30.97  $objects | Select-Object -ExpandProperty Name 0.140
32.76  $objects | % Name                             0.148
  • Windows PowerShell v5.1.18362.145
Factor Command                                       Secs (10-run avg.)
------ -------                                       ------------------
1.00   $objects.Name                                 0.012
1.32   foreach($o in $objects) { $o.Name }           0.015
9.07   $objects.ForEach({ $_.Name })                 0.105
10.30  $objects.ForEach('Name')                      0.119
12.70  $objects | % { $_.Name }                      0.147
27.04  $objects | % Name                             0.312
29.70  $objects | Select-Object -ExpandProperty Name 0.343


  • In PowerShell Core, .ForEach('Name') clearly outperforms .ForEach({ $_.Name }). In Windows PowerShell, curiously, the latter is faster, albeit only marginally so.

Timings with [pscustomobject] instances:

  • PowerShell Core v7.0.0-preview.3
Factor Command                                       Secs (10-run avg.)
------ -------                                       ------------------
1.00   $objects.Name                                 0.006
1.11   foreach($o in $objects) { $o.Name }           0.007
1.52   $objects.ForEach('Name')                      0.009
6.11   $objects.ForEach({ $_.Name })                 0.038
9.47   $objects | Select-Object -ExpandProperty Name 0.058
10.29  $objects | % { $_.Name }                      0.063
29.77  $objects | % Name                             0.184
  • Windows PowerShell v5.1.18362.145
Factor Command                                       Secs (10-run avg.)
------ -------                                       ------------------
1.00   $objects.Name                                 0.008
1.14   foreach($o in $objects) { $o.Name }           0.009
1.76   $objects.ForEach('Name')                      0.015
10.36  $objects | Select-Object -ExpandProperty Name 0.085
11.18  $objects.ForEach({ $_.Name })                 0.092
16.79  $objects | % { $_.Name }                      0.138
61.14  $objects | % Name                             0.503


  • Note how with [pscustomobject] input .ForEach('Name') by far outperforms the script-block based variant, .ForEach({ $_.Name }).

  • Similarly, [pscustomobject] input makes the pipeline-based Select-Object -ExpandProperty Name faster, in Windows PowerShell virtually on par with .ForEach({ $_.Name }), but in PowerShell Core still about 50% slower.

  • In short: With the odd exception of % Name, with [pscustomobject] the string-based methods of referencing the properties outperform the scriptblock-based ones.

Source code for the tests:


  • Download function Time-Command from this Gist to run these tests.

    • Assuming you have looked at the linked code to ensure that it is safe (which I can personally assure you of, but you should always check), you can install it directly as follows:

      irm | iex
  • Set $useCustomObjectInput to $true to measure with [pscustomobject] instances instead.

$count = 1e4 # max. input object count == 10,000
$runs  = 10  # number of runs to average 

# Note: Using [pscustomobject] instances rather than instances of 
#       regular .NET types changes the performance characteristics.
# Set this to $true to test with [pscustomobject] instances below.
$useCustomObjectInput = $false

# Create sample input objects.
if ($useCustomObjectInput) {
  # Use [pscustomobject] instances.
  $objects = 1..$count | % { [pscustomobject] @{ Name = "$foobar_$_"; Other1 = 1; Other2 = 2; Other3 = 3; Other4 = 4 } }
} else {
  # Use instances of a regular .NET type.
  # Note: The actual count of files and folders in your file-system
  #       may be less than $count
  $objects = Get-ChildItem / -Recurse -ErrorAction Ignore | Select-Object -First $count

Write-Host "Comparing property-value extraction methods with $($objects.Count) input objects, averaged over $runs runs..."

# An array of script blocks with the various approaches.
$approaches = { $objects | Select-Object -ExpandProperty Name },
              { $objects | % Name },
              { $objects | % { $_.Name } },
              { $objects.ForEach('Name') },
              { $objects.ForEach({ $_.Name }) },
              { $objects.Name },
              { foreach($o in $objects) { $o.Name } }

# Time the approaches and sort them by execution time (fastest first):
Time-Command $approaches -Count $runs | Select Factor, Command, Secs*

[1] Technically, even a command without |, the pipeline operator, uses a pipeline behind the scenes, but for the purpose of this discussion using the pipeline refers only to commands that do use | and therefore involve multiple commands connected by a pipeline.

What is the difference between @Inject and @Autowired in Spring Framework? Which one to use under what condition?

Here is a blog post that compares @Resource, @Inject, and @Autowired, and appears to do a pretty comprehensive job.

From the link:

With the exception of test 2 & 7 the configuration and outcomes were identical. When I looked under the hood I determined that the ‘@Autowired’ and ‘@Inject’ annotation behave identically. Both of these annotations use the ‘AutowiredAnnotationBeanPostProcessor’ to inject dependencies. ‘@Autowired’ and ‘@Inject’ can be used interchangeable to inject Spring beans. However the ‘@Resource’ annotation uses the ‘CommonAnnotationBeanPostProcessor’ to inject dependencies. Even though they use different post processor classes they all behave nearly identically. Below is a summary of their execution paths.

Tests 2 and 7 that the author references are 'injection by field name' and 'an attempt at resolving a bean using a bad qualifier', respectively.

The Conclusion should give you all the information you need.

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

It's funny how other answers ignore the fact that you can't write to that file...

There are a few workarounds that come to my mind which could help use an arbitrary C:\redirected\settings.xml and use the mvn command as usual happily ever after.

mvn alias

In a Unix shell (or on Cygwin) you can create

alias mvn='mvn --global-settings "C:\redirected\settings.xml"'

so when you're calling mvn blah blah from anywhere the config is "automatically" picked up.
See How to create alias in cmd? if you want this, but don't have a Unix shell.

mvn wrapper

Configure your environment so that mvn is resolved to a wrapper script when typed in the command line:

  • Remove your MVN_HOME/bin or M2_HOME/bin from your PATH so mvn is not resolved any more.
  • Add a folder to PATH (or use an existing one)
  • In that folder create an mvn.bat file with contents:

    call C:\your\path\to\maven\bin\mvn.bat --global-settings "C:\redirected\settings.xml" %*

Note: if you want some projects to behave differently you can just create mvn.bat in the same folder as pom.xml so when you run plain mvn it resolves to the local one.

Use where mvn at any time to check how it is resolved, the first one will be run when you type mvn.

mvn.bat hack

If you have write access to C:\your\path\to\maven\bin\mvn.bat, edit the file and add set MAVEN_CMD_LINE_ARG to the :runm2 part:

set MAVEN_CMD_LINE_ARGS=--global-settings "C:\redirected\settings.xml" %MAVEN_CMD_LINE_ARGS%

For completeness, you can change the C:\your\path\to\maven\bin\mvn shell script too by changing the exec "$JAVACMD" command's


part to

${CLASSWORLDS_LAUNCHER} --global-settings "C:\redirected\settings.xml" "$@"


As a person in IT it's funny that you don't have access to your own home folder, for me this constitutes as incompetence from the company you're working for: this is equivalent of hiring someone to do software development, but not providing even the possibility to use anything other than notepad.exe or Microsoft Word to edit the source files. I'd suggest to contact your help desk or administrator and request write access at least to that particular file so that you can change the path of the local repository.

Disclaimer: None of these are tested for this particular use case, but I successfully used all of them previously for various other software.

Microsoft Visual C++ 14.0 is required (Unable to find vcvarsall.bat)

I was facing the same problem. The following worked for me: Download the unoffical binaries file from Christoph Gohlke installers site as per the python version installed on your system. Navigate to the folder where you have installed the file and run

pip install filename

For me python_ldap-3.0.0-cp35-cp35m-win_amd64.whl worked as my machine is 64 bit and python version is 3.5. This successfully installed python-ldap on my windows machine. You can try the same for mysql-python

Python datetime to string without microsecond component

>>> from datetime import datetime
>>> dt ="%Y-%m-%d %X")
>>> print(dt)
'2021-02-05 04:10:24'

R: Select values from data table in range

Lots of options here, but one of the easiest to follow is subset. Consider:

> set.seed(43)
> df <- data.frame(name = sample(letters, 100, TRUE), date = sample(1:500, 100, TRUE))
> subset(df, date > 5 & date < 15)
   name date
11    k   10
67    y   12
86    e    8

You can also insert logic directly into the index for your data.frame. The comma separates the rows from columns. We just have to remember that R indexes rows first, then columns. So here we are saying rows with date > 5 & < 15 and then all columns:

df[df$date > 5 & df$date < 15 ,]

I'd also recommend checking out the help pages for subset, ?subset and the logical operators ?"&"

Regular expression for a hexadecimal number?

This one makes sure you have no more than three valid pairs:


Any more or less than three pairs of valid characters fail to match.

Using prepared statements with JDBCTemplate

class Main {
    public static void main(String args[]) throws Exception {
        ApplicationContext ac = new
          ClassPathXmlApplicationContext("context.xml", Main.class);
        DataSource dataSource = (DataSource) ac.getBean("dataSource");
// DataSource mysqlDataSource = (DataSource) ac.getBean("mysqlDataSource");

        JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);

        String prasobhName = 
           "select first_name from customer where last_name like ?",
            new PreparedStatementSetter() {
              public void setValues(PreparedStatement preparedStatement) throws
                SQLException {
                  preparedStatement.setString(1, "nair%");
            new ResultSetExtractor<Long>() {
              public Long extractData(ResultSet resultSet) throws SQLException,
                DataAccessException {
                  if ( {
                      return resultSet.getLong(1);
                  return null;

Java: get greatest common divisor

Unless I have Guava, I define like this:

int gcd(int a, int b) {
  return a == 0 ? b : gcd(b % a, a);

Using intents to pass data between activities

Main Activity

public class MainActivity extends Activity {

    EditText user, password;
    Button login;

    protected void onCreate(Bundle savedInstanceState) {

        user = (EditText) findViewById(;
        password = (EditText) findViewById(;
        login = (Button) findViewById(;
        login.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this,Second.class);

                String uservalue = user.getText().toString();
                String name_value = password.getText().toString();
                String password_value = password.getText().toString();

                intent.putExtra("username", uservalue);
                intent.putExtra("password", password_value);

Second Activity in which you want to receive Data

public class Second extends Activity{

    EditText name, pass;

    protected void onCreate(Bundle savedInstanceState) {


        name = (EditText) findViewById(;
        pass = (EditText) findViewById(;

        String value = getIntent().getStringExtra("username");
        String pass_val = getIntent().getStringExtra("password");

Strange Characters in database text: Ã, Ã, ¢, â‚ €,

This is surely an encoding problem. You have a different encoding in your database and in your website and this fact is the cause of the problem. Also if you ran that command you have to change the records that are already in your tables to convert those character in UTF-8.

Update: Based on your last comment, the core of the problem is that you have a database and a data source (the CSV file) which use different encoding. Hence you can convert your database in UTF-8 or, at least, when you get the data that are in the CSV, you have to convert them from UTF-8 to latin1.

You can do the convertion following this articles:

How to read a file in Groovy into a string?

String fileContents = new File('/path/to/file').text

If you need to specify the character encoding, use the following instead:

String fileContents = new File('/path/to/file').getText('UTF-8')

Is there a splice method for strings?

I solved my problem using this code, is a somewhat replacement for the missing splice.

let str = "I need to remove a character from this";
let pos = str.indexOf("character")

  let result = str.slice(0, pos-2) + str.slice(pos, str.length);
  console.log(result) //I need to remove character from this 

I needed to remove a character before/after a certain word, after you get the position the string is split in two and then recomposed by flexibly removing characters using an offset along pos

How do I split a string so I can access item x?

I don't believe SQL Server has a built-in split function, so other than a UDF, the only other answer I know is to hijack the PARSENAME function:

SELECT PARSENAME(REPLACE('Hello John Smith', ' ', '.'), 2) 

PARSENAME takes a string and splits it on the period character. It takes a number as its second argument, and that number specifies which segment of the string to return (working from back to front).

SELECT PARSENAME(REPLACE('Hello John Smith', ' ', '.'), 3)  --return Hello

Obvious problem is when the string already contains a period. I still think using a UDF is the best way...any other suggestions?

Difference between DTO, VO, POJO, JavaBeans?


A JavaBean is a class that follows the JavaBeans conventions as defined by Sun. Wikipedia has a pretty good summary of what JavaBeans are:

JavaBeans are reusable software components for Java that can be manipulated visually in a builder tool. Practically, they are classes written in the Java programming language conforming to a particular convention. They are used to encapsulate many objects into a single object (the bean), so that they can be passed around as a single bean object instead of as multiple individual objects. A JavaBean is a Java Object that is serializable, has a nullary constructor, and allows access to properties using getter and setter methods.

In order to function as a JavaBean class, an object class must obey certain conventions about method naming, construction, and behavior. These conventions make it possible to have tools that can use, reuse, replace, and connect JavaBeans.

The required conventions are:

  • The class must have a public default constructor. This allows easy instantiation within editing and activation frameworks.
  • The class properties must be accessible using get, set, and other methods (so-called accessor methods and mutator methods), following a standard naming convention. This allows easy automated inspection and updating of bean state within frameworks, many of which include custom editors for various types of properties.
  • The class should be serializable. This allows applications and frameworks to reliably save, store, and restore the bean's state in a fashion that is independent of the VM and platform.

Because these requirements are largely expressed as conventions rather than by implementing interfaces, some developers view JavaBeans as Plain Old Java Objects that follow specific naming conventions.


A Plain Old Java Object or POJO is a term initially introduced to designate a simple lightweight Java object, not implementing any javax.ejb interface, as opposed to heavyweight EJB 2.x (especially Entity Beans, Stateless Session Beans are not that bad IMO). Today, the term is used for any simple object with no extra stuff. Again, Wikipedia does a good job at defining POJO:

POJO is an acronym for Plain Old Java Object. The name is used to emphasize that the object in question is an ordinary Java Object, not a special object, and in particular not an Enterprise JavaBean (especially before EJB 3). The term was coined by Martin Fowler, Rebecca Parsons and Josh MacKenzie in September 2000:

"We wondered why people were so against using regular objects in their systems and concluded that it was because simple objects lacked a fancy name. So we gave them one, and it's caught on very nicely."

The term continues the pattern of older terms for technologies that do not use fancy new features, such as POTS (Plain Old Telephone Service) in telephony, and PODS (Plain Old Data Structures) that are defined in C++ but use only C language features, and POD (Plain Old Documentation) in Perl.

The term has most likely gained widespread acceptance because of the need for a common and easily understood term that contrasts with complicated object frameworks. A JavaBean is a POJO that is serializable, has a no-argument constructor, and allows access to properties using getter and setter methods. An Enterprise JavaBean is not a single class but an entire component model (again, EJB 3 reduces the complexity of Enterprise JavaBeans).

As designs using POJOs have become more commonly-used, systems have arisen that give POJOs some of the functionality used in frameworks and more choice about which areas of functionality are actually needed. Hibernate and Spring are examples.

Value Object

A Value Object or VO is an object such as java.lang.Integer that hold values (hence value objects). For a more formal definition, I often refer to Martin Fowler's description of Value Object:

In Patterns of Enterprise Application Architecture I described Value Object as a small object such as a Money or date range object. Their key property is that they follow value semantics rather than reference semantics.

You can usually tell them because their notion of equality isn't based on identity, instead two value objects are equal if all their fields are equal. Although all fields are equal, you don't need to compare all fields if a subset is unique - for example currency codes for currency objects are enough to test equality.

A general heuristic is that value objects should be entirely immutable. If you want to change a value object you should replace the object with a new one and not be allowed to update the values of the value object itself - updatable value objects lead to aliasing problems.

Early J2EE literature used the term value object to describe a different notion, what I call a Data Transfer Object. They have since changed their usage and use the term Transfer Object instead.

You can find some more good material on value objects on the wiki and by Dirk Riehle.

Data Transfer Object

Data Transfer Object or DTO is a (anti) pattern introduced with EJB. Instead of performing many remote calls on EJBs, the idea was to encapsulate data in a value object that could be transfered over the network: a Data Transfer Object. Wikipedia has a decent definition of Data Transfer Object:

Data transfer object (DTO), formerly known as value objects or VO, is a design pattern used to transfer data between software application subsystems. DTOs are often used in conjunction with data access objects to retrieve data from a database.

The difference between data transfer objects and business objects or data access objects is that a DTO does not have any behaviour except for storage and retrieval of its own data (accessors and mutators).

In a traditional EJB architecture, DTOs serve dual purposes: first, they work around the problem that entity beans are not serializable; second, they implicitly define an assembly phase where all data to be used by the view is fetched and marshalled into the DTOs before returning control to the presentation tier.

So, for many people, DTOs and VOs are the same thing (but Fowler uses VOs to mean something else as we saw). Most of time, they follow the JavaBeans conventions and are thus JavaBeans too. And all are POJOs.

Pip error: Microsoft Visual C++ 14.0 is required

I got this error when I tried to install pymssql even though Visual C++ 2015 (14.0) is installed in my system.

I resolved this error by downloading the .whl file of pymssql from here.

Once downloaded, it can be installed by the following command :

pip install python_package.whl

Hope this helps

How to split a string by spaces in a Windows batch file?

If someone need to split a string with any delimiter and store values in separate variables, here is the script I built,

FOR /F "tokens=1,2 delims=x" %i in ("1920x1080") do (
  set w=%i
  set h=%j
echo %w%
echo %h%

Explanation: 'tokens' defines what elements you need to pass to the body of FOR, with token delimited by character 'x'. So after delimiting, the first and second token are passed to the body. In the body %i refers to first token and %j refers to second token. We can take %k to refer to 3rd token and so on..

Please also type HELP FOR in cmd to get a detailed explanation.

Facebook Graph API v2.0+ - /me/friends returns empty, or only friends who also use my application

In Swift 4.2 and Xcode 10.1:

If you want to get the friends list from Facebook, you need to submit your app for review in Facebook. See some of the Login Permissions:

Login Permissions

Here are the two steps:

1) First your app status is must be in Live

2) Get required permissions form Facebook.

1) Enable our app status live:

  1. Go to the apps page and select your app

  2. Select status in the top right in Dashboard.

    Enter image description here

  3. Submit privacy policy URL

    Enter image description here

  4. Select category

    Enter image description here

  5. Now our app is in Live status.

    Enter image description here

One step is completed.

2) Submit our app for review:

  1. First send required requests.

    Example: user_friends, user_videos, user_posts, etc.

    Enter image description here

  2. Second, go to the Current Request page

    Enter image description here

    Example: user_events

  3. Submit all details

    Enter image description here

  4. Like this submit for all requests (user_friends , user_events, user_videos, user_posts, etc.).

  5. Finally submit your app for review.

    If your review is accepted from Facebook's side, you are now eligible to read contacts, etc.

Python one-line "for" expression

If you really only need to add the items in one array to another, the '+' operator is already overloaded to do that, incidentally:

a1 = [1,2,3,4,5]
a2 = [6,7,8,9]
a1 + a2
--> [1, 2, 3, 4, 5, 6, 7, 8, 9]

Migration: Cannot add foreign key constraint

Question already answered, but hope this might help someone else.

This error occurred for me because I created the migration table with the foreign key in it firstly before the key existed as a primary key in it's original table. Migrations get executed in the order they were created as indicated by the file name generated after running migrate:make. E.g. 2014_05_10_165709_create_student_table.php.

The solution was to rename the file with the foreign key to an earlier time than the file with the primary key as recommended here:

I think I also had to add in $table->engine = 'InnoDB';

package R does not exist

If this error appeared after resolving merge conflicts, simple Build -> Clean project could help.

How to run C program on Mac OS X using Terminal?

Working in 2019 By default, you can compile your name.c using the terminal

 cc name.c

and if you need to run just write


Including an anchor tag in an ASP.NET MVC Html.ActionLink

I would probably build the link manually, like this:

<a href="<%=Url.Action("Subcategory", "Category", new { categoryID = parent.ID }) %>#section12">link text</a>

Cannot install Aptana Studio 3.6 on Windows

It seems having msysgit (Git for Windows) installed is causing the problem.

In most cases you'll have a pretty recent version of Git for Windows installed. Cited from

There was a security issue in Git, see here. Git for Windows < 1.9.5 is affected - so you should update, TortoiseGit itself is not affected (using the default configuration; only if libgit2 is manually enabled for checkout/fetching). TortoiseGit includes all fixes.

But it seems Aptana Studio Installer won't accept any pre-installed version of Git for Windows!

What you need to do:

  1. Uninstall Git for Windows.
  2. Install Aptana Studio.
    Apanta Studio 3.6.1 will install Git for Windows 1.8.4-preview20130916.
  3. Download latest version of Git for Windows from
  4. Install latest version of Git for Windows.
    The outdated Git for Windows 1.8.4-preview20130916 will be updated to recent version.

That's it !!!

How can I use the python HTMLParser library to extract data from a specific div tag?

This works perfectly:

print (soup.find('the tag').text)

How to set time to 24 hour format in Calendar

I am using fullcalendar on my project recently, I don't know what exact view effect you want to achieve, in my project I want to change the event time view from 12h format from

enter image description here

to 24h format.

enter image description here

If this is the effect you want to achieve, the solution below might help:

set timeFormat: 'H:mm'

Simple VBA selection: Selecting 5 cells to the right of the active cell

This copies the 5 cells to the right of the activecell. If you have a range selected, the active cell is the top left cell in the range.

Sub Copy5CellsToRight()
    ActiveCell.Offset(, 1).Resize(1, 5).Copy
End Sub

If you want to include the activecell in the range that gets copied, you don't need the offset:

Sub ExtendAndCopy5CellsToRight()
    ActiveCell.Resize(1, 6).Copy
End Sub

Note that you don't need to select before copying.

How do I return an int from EditText? (Android)

For now, use an EditText. Use android:inputType="number" to force it to be numeric. Convert the resulting string into an integer (e.g., Integer.parseInt(myEditText.getText().toString())).

In the future, you might consider a NumberPicker widget, once that becomes available (slated to be in Honeycomb).

AngularJS. How to call controller function from outside of controller component

I've found an example on the internet.

Some guy wrote this code and worked perfectly


<div ng-cloak ng-app="ManagerApp">
    <div id="MainWrap" class="container" ng-controller="ManagerCtrl">
       <span class="label label-info label-ext">Exposing Controller Function outside the module via onClick function call</span>
       <button onClick='ajaxResultPost("Update:Name:With:JOHN","accept",true);'>click me</button>
       <br/> <span class="label label-warning label-ext" ng-bind=""></span>
       <br/> <span class="label label-warning label-ext" ng-bind="customParams.type"></span>
       <br/> <span class="label label-warning label-ext" ng-bind="customParams.res"></span>
       <input type="text" ng-model="sampletext" size="60">


var angularApp = angular.module('ManagerApp', []);
angularApp.controller('ManagerCtrl', ['$scope', function ($scope) {

$scope.customParams = {};

$scope.updateCustomRequest = function (data, type, res) {
    $ = data;
    $scope.customParams.type = type;
    $scope.customParams.res = res;
    $scope.sampletext = "input text: " + data;


function ajaxResultPost(data, type, res) {
    var scope = angular.element(document.getElementById("MainWrap")).scope();
    scope.$apply(function () {
    scope.updateCustomRequest(data, type, res);


*I did some modifications, see original: font JSfiddle

Private class declaration

You can't have private class but you can have second class:

public class App14692708 {
    public static void main(String[] args) {
        PC pc = new PC();

class PC {
    public String toString() {
        return "I am PC instance " + super.toString();

Also remember that static inner class is indistinguishable of separate class except it's name is OuterClass.InnerClass. So if you don't want to use "closures", use static inner class.

WCF timeout exception detailed investigation

I'm having a very similar problem. In the past, this has been related to serialization problems. If you are still having this problem, can you verify that you can correctly serialize the objects you are returning. Specifically, if you are using Linq-To-Sql objects that have relationships, there are known serialization problems if you put a back reference on a child object to the parent object and mark that back reference as a DataMember.

You can verify serialization by writing a console app that serializes and deserializes your objects using the DataContractSerializer on the server side and whatever serialization methods your client uses. For example, in our current application, we have both WPF and Compact Framework clients. I wrote a console app to verify that I can serialize using a DataContractSerializer and deserialize using an XmlDesserializer. You might try that.

Also, if you are returning Linq-To-Sql objects that have child collections, you might try to ensure that you have eagerly loaded them on the server side. Sometimes, because of lazy loading, the objects being returned are not populated and may cause the behavior you are seeing where the request is sent to the service method multiple times.

If you have solved this problem, I'd love to hear how because I'm stuck with it too. I have verified that my issue is not serialization so I'm at a loss.

UPDATE: I'm not sure if it will help you any but the Service Trace Viewer Tool just solved my problem after 5 days of very similar experience to yours. By setting up tracing and then looking at the raw XML, I found the exceptions that were causing my serialization problems. It was related to Linq-to-SQL objects that occasionally had more child objects than could be successfully serialized. Adding the following to your web.config file should enable tracing:

    <add name="sharedListener"
         initializeData="c:\Temp\servicetrace.svclog" />
    <source name="System.ServiceModel" switchValue="Verbose, ActivityTracing" >
        <add name="sharedListener" />
    <source name="System.ServiceModel.MessageLogging" switchValue="Verbose">
        <add name="sharedListener" />

The resulting file can be opened with the Service Trace Viewer Tool or just in IE to examine the results.

How to deserialize a JObject to .NET object

Too late, just in case some one is looking for another way:

void Main()
    string jsonString = @"{
  'Stores': [
    'Lambton Quay',
    'Willis Street'
  'Manufacturers': [
      'Name': 'Acme Co',
      'Products': [
          'Name': 'Anvil',
          'Price': 50
      'Name': 'Contoso',
      'Products': [
          'Name': 'Elbow Grease',
          'Price': 99.95
          'Name': 'Headlight Fluid',
          'Price': 4

    Product product = new Product();
    //Serializing to Object
    Product obj = JObject.Parse(jsonString).SelectToken("$.Manufacturers[?(@.Name == 'Acme Co' && @.Name != 'Contoso')]").ToObject<Product>();


public class Product
    public string Name { get; set; }
    public decimal Price { get; set; }