Programs & Examples On #Swtbot

SWTBot is an open-source Java based UI/functional testing tool for testing SWT and Eclipse based applications.

Onclick CSS button effect

JS provides the tools to do this the right way. Try the demo snippet.

enter image description here

var doc = document;_x000D_
var buttons = doc.getElementsByTagName('button');_x000D_
var button = buttons[0];_x000D_
button.addEventListener("mouseover", function(){_x000D_
button.addEventListener("mouseout", function(){_x000D_
button.addEventListener("mousedown", function(){_x000D_
button.addEventListener("mouseup", function(){_x000D_
  alert('Button Clicked!');_x000D_
//this is unrelated to button styling.  It centers the button._x000D_
var box = doc.getElementById('box');_x000D_
var boxHeight = window.innerHeight;_x000D_ = boxHeight + 'px'; 
  text-transform: uppercase;_x000D_
  background-color:rgba(66, 66, 66,0.3);_x000D_
  -webkit-box-shadow: 0px 10px 5px -4px rgba(0,0,0,0.33);_x000D_
  -moz-box-shadow: 0px 10px 5px -4px rgba(0,0,0,0.33);_x000D_
  box-shadow: 0px 10px 5px -4px rgba(0,0,0,0.33);_x000D_
button:focus {_x000D_
  background-color:rgba(66, 66, 66,0.34);_x000D_
  -webkit-box-shadow: 0px 6px 5px -4px rgba(0,0,0,0.52);_x000D_
  -moz-box-shadow: 0px 6px 5px -4px rgba(0,0,0,0.52);_x000D_
  box-shadow: 0px 6px 5px -4px rgba(0,0,0,0.52);                 _x000D_
/* unrelated to button styling */_x000D_
#box {_x000D_
  display: flex;_x000D_
  flex-flow: row nowrap ;_x000D_
  justify-content: center;_x000D_
  align-content: center;_x000D_
  align-items: center;_x000D_
button {_x000D_
  flex: 0 1 auto;_x000D_
  align-self: auto;_x000D_
  min-width: 0;_x000D_
  min-height: auto;_x000D_
}            _x000D_
<!DOCTYPE html>_x000D_
<html lang="en">_x000D_
    <meta charset=utf-8 />_x000D_
    <meta name="description" content="3d Button Configuration" />_x000D_
    <section id="box">_x000D_

Read Excel File in Python

By using pandas we can read excel easily.

import pandas as pd 
from pandas import ExcelWriter
from pandas import ExcelFile 


print("Column headings:")

Test at : Reference:

Update Android SDK Tool to 22.0.4(Latest Version) from 22.0.1

I'm on OSX, I was using Android Studio instead of ADT and I had this issue, my problem was being behind a proxy with authentication, for what ever reason, In Android SDK Manager Window, under Preferences -> Others, I needed to uncheck the

"Force https://... sources to be fetched using http://..."

Also, there was no place to put the proxy credentials, but it will prompt you for them.

c++ array - expression must have a constant value

The standard requires the array length to be a value that is computable at compile time so that the compiler is able to allocate enough space on the stack. In your case, you are trying to set the array length to a value that is unknown at compile time. Yes, i know that it seems obvious that it should be known to the compiler, but this is not the case here. The compiler cannot make any assumptions about the contents of non-constant variables. So go with:

const int row = 8;
const int col= 8;
int a[row][col];

UPD: some compilers will actually allow you to pull this off. IIRC, g++ has this feature. However, never use it because your code will become un-portable across compilers.

Share link on Google+

Yes, you can.

Edit: It works only with

Edit: As of March 2012 it works on all sites.

Documentation for this sharing method is available on the Google Developers site.

clk'event vs rising_edge()

The linked comment is incorrect : 'L' to '1' will produce a rising edge.

In addition, if your clock signal transitions from 'H' to '1', rising_edge(clk) will (correctly) not trigger while (clk'event and clk = '1') (incorrectly) will.

Granted, that may look like a contrived example, but I have seen clock waveforms do that in real hardware, due to failures elsewhere.

Simple 3x3 matrix inverse code (C++)

//Function for inverse of the input square matrix 'J' of dimension 'dim':

vector<vector<double > > inverseVec33(vector<vector<double > > J, int dim)
//Matrix of Minors
 vector<vector<double > > invJ(dim,vector<double > (dim));
for(int i=0; i<dim; i++)
    for(int j=0; j<dim; j++)
        invJ[i][j] = (J[(i+1)%dim][(j+1)%dim]*J[(i+2)%dim][(j+2)%dim] -

//determinant of the matrix:
double detJ = 0.0;
for(int j=0; j<dim; j++)
{ detJ += J[0][j]*invJ[0][j];}

//Inverse of the given matrix.
 vector<vector<double > > invJT(dim,vector<double > (dim));
 for(int i=0; i<dim; i++)
    for(int j=0; j<dim; j++)
        invJT[i][j] = invJ[j][i]/detJ;

return invJT;

void main()
    //given matrix:
vector<vector<double > > Jac(3,vector<double > (3));
Jac[0][0] = 1; Jac[0][1] = 2;  Jac[0][2] = 6;
Jac[1][0] = -3; Jac[1][1] = 4;  Jac[1][2] = 3;
Jac[2][0] = 5; Jac[2][1] = 1;  Jac[2][2] = -4;`

//Inverse of the matrix Jac:
vector<vector<double > > JacI(3,vector<double > (3));
    //call function and store inverse of J as JacI:
JacI = inverseVec33(Jac,3);

How can I use the HTML5 canvas element in IE?

If you need to use IE8, you can try this JavaScript library for vector graphics. It is like solving the "canvas" and "SVG" incompatibilities of IE8 at the same time.


I have just try it in a fast example and it works correctly. I don't know how legible is the source code but I hope it helps you. As they said in its site, the library is compatible with very old explorers.

Raphaël currently supports Firefox 3.0+, Safari 3.0+, Chrome 5.0+, Opera 9.5+ and Internet Explorer 6.0+.

UILabel with text of two different colors

Swift 4

// An attributed string extension to achieve colors on text.
extension NSMutableAttributedString {

    func setColor(color: UIColor, forText stringValue: String) {
       let range: NSRange = self.mutableString.range(of: stringValue, options: .caseInsensitive)
       self.addAttribute(NSAttributedStringKey.foregroundColor, value: color, range: range)


// Try it with label
let label = UILabel()
label.frame = CGRect(x: 70, y: 100, width: 260, height: 30)
let stringValue = "There are 5 results."
let attributedString: NSMutableAttributedString = NSMutableAttributedString(string: stringValue)
attributedString.setColor(color:, forText: "5")
label.font = UIFont.systemFont(ofSize: 26)
label.attributedText = attributedString


enter image description here

Swift 3

func setColoredLabel() {
        var string: NSMutableAttributedString = NSMutableAttributedString(string: "redgreenblue")
        string.setColor(color: UIColor.redColor(), forText: "red")
        string.setColor(color: UIColor.greenColor(), forText: "green")
        string.setColor(color: UIColor.blueColor(, forText: "blue")
        mylabel.attributedText = string

func setColor(color: UIColor, forText stringValue: String) {
        var range: NSRange = self.mutableString.rangeOfString(stringValue, options: NSCaseInsensitiveSearch)
        if range != nil {
            self.addAttribute(NSForegroundColorAttributeName, value: color, range: range)


enter image description here

Java keytool easy way to add server cert from url/port

Was looking at how to trust a certificate while using jenkins cli, and found which has some recipe for that.

This will give you the certificate:

openssl s_client -connect ${HOST}:${PORT} </dev/null

if you are interested only in the certificate part, cut it out by piping it to:


and redirect to a file:

> ${HOST}.cert

Then import it using keytool:

keytool -import -noprompt -trustcacerts -alias ${HOST} -file ${HOST}.cert \
    -keystore ${KEYSTOREFILE} -storepass ${KEYSTOREPASS}

In one go:

# get the SSL certificate
openssl s_client -connect ${HOST}:${PORT} </dev/null \
    | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > ${HOST}.cert

# create a keystore and import certificate
keytool -import -noprompt -trustcacerts \
    -alias ${HOST} -file ${HOST}.cert \
    -keystore ${KEYSTOREFILE} -storepass ${KEYSTOREPASS}

# verify we've got it.
keytool -list -v -keystore ${KEYSTOREFILE} -storepass ${KEYSTOREPASS} -alias ${HOST}

How do I add a user when I'm using Alpine as a base image?

The commands are adduser and addgroup.

Here's a template for Docker you can use in busybox environments (alpine) as well as Debian-based environments (Ubuntu, etc.):

ENV USER=docker
ENV UID=12345
ENV GID=23456

RUN adduser \
    --disabled-password \
    --gecos "" \
    --home "$(pwd)" \
    --ingroup "$USER" \
    --no-create-home \
    --uid "$UID" \

Note the following:

  • --disabled-password prevents prompt for a password
  • --gecos "" circumvents the prompt for "Full Name" etc. on Debian-based systems
  • --home "$(pwd)" sets the user's home to the WORKDIR. You may not want this.
  • --no-create-home prevents cruft getting copied into the directory from /etc/skel

The usage description for these applications is missing the long flags present in the code for adduser and addgroup.

The following long-form flags should work both in alpine as well as debian-derivatives:


BusyBox v1.28.4 (2018-05-30 10:45:57 UTC) multi-call binary.

Usage: adduser [OPTIONS] USER [GROUP]

Create new user, or add USER to GROUP

        --home DIR           Home directory
        --gecos GECOS        GECOS field
        --shell SHELL        Login shell
        --ingroup GRP        Group (by name)
        --system             Create a system user
        --disabled-password  Don't assign a password
        --no-create-home     Don't create home directory
        --uid UID            User id

One thing to note is that if --ingroup isn't set then the GID is assigned to match the UID. If the GID corresponding to the provided UID already exists adduser will fail.


BusyBox v1.28.4 (2018-05-30 10:45:57 UTC) multi-call binary.

Usage: addgroup [-g GID] [-S] [USER] GROUP

Add a group or add a user to a group

        --gid GID  Group id
        --system   Create a system group

I discovered all of this while trying to write my own alternative to the fixuid project for running containers as the hosts UID/GID.

My entrypoint helper script can be found on GitHub.

The intent is to prepend that script as the first argument to ENTRYPOINT which should cause Docker to infer UID and GID from a relevant bind mount.

An environment variable "TEMPLATE" may be required to determine where the permissions should be inferred from.

(At the time of writing I don't have documentation for my script. It's still on the todo list!!)

Removing duplicate characters from a string

#Check code and apply in your Program:

#Input= 'pppmm'    
s = 'ppppmm'
s = ''.join(set(s))  
#Output: pm

Can I change the viewport meta tag in mobile safari on the fly?

in your <head>

<meta id="viewport"
      content="width=1024, height=768, initial-scale=0, minimum-scale=0.25" />

somewhere in your javascript

      "initial-scale=0.5; maximum-scale=1.0; user-scalable=0;");

... but good luck with tweaking it for your device, fiddling for hours... and i'm still not there!


Java - How to create a custom dialog box?

This lesson from the Java tutorial explains each Swing component in detail, with examples and API links.

How to close IPython Notebook properly?

I think accepted answer outdated and is not valid anymore.

You can terminate jupyter notebook from web interface on file menü item.

enter image description here

When you move Mouse cursor on "close and halt", you will see following explanation.

enter image description here

And when you click "close and halt", you will see following message on terminal screen.

enter image description here

Comparing object properties in c#

I ended up doing this:

    public static string ToStringNullSafe(this object obj)
        return obj != null ? obj.ToString() : String.Empty;
    public static bool Compare<T>(T a, T b)
        int count = a.GetType().GetProperties().Count();
        string aa, bb;
        for (int i = 0; i < count; i++)
            aa = a.GetType().GetProperties()[i].GetValue(a, null).ToStringNullSafe();
            bb = b.GetType().GetProperties()[i].GetValue(b, null).ToStringNullSafe();
            if (aa != bb)
                return false;
        return true;


    if (Compare<ObjectType>(a, b))


If you want to ignore some properties by name:

    public static string ToStringNullSafe(this object obj)
        return obj != null ? obj.ToString() : String.Empty;
    public static bool Compare<T>(T a, T b, params string[] ignore)
        int count = a.GetType().GetProperties().Count();
        string aa, bb;
        for (int i = 0; i < count; i++)
            aa = a.GetType().GetProperties()[i].GetValue(a, null).ToStringNullSafe();
            bb = b.GetType().GetProperties()[i].GetValue(b, null).ToStringNullSafe();
            if (aa != bb && ignore.Where(x => x == a.GetType().GetProperties()[i].Name).Count() == 0)
                return false;
        return true;


    if (MyFunction.Compare<ObjType>(a, b, "Id","AnotherProp"))

How do I force git to checkout the master branch and remove carriage returns after I've normalized files using the "text" attribute?

As others have pointed out one could just delete all the files in the repo and then check them out. I prefer this method and it can be done with the code below

git ls-files -z | xargs -0 rm
git checkout -- .

or one line

git ls-files -z | xargs -0 rm ; git checkout -- .

I use it all the time and haven't found any down sides yet!

For some further explanation, the -z appends a null character onto the end of each entry output by ls-files, and the -0 tells xargs to delimit the output it was receiving by those null characters.

What does the question mark in Java generics' type parameter mean?

In English:

It's a List of some type that extends the class HasWord, including HasWord

In general the ? in generics means any class. And the extends SomeClass specifies that that object must extend SomeClass (or be that class).

Correctly ignore all files recursively under a specific folder except for a specific file type

This might look stupid, but check if you haven't already added the folder/files you are trying to ignore to the index before. If you did, it does not matter what you put in your .gitignore file, the folders/files will still be staged.

Relational Database Design Patterns?

AskTom is probably the single most helpful resource on best practices on Oracle DBs. (I usually just type "asktom" as the first word of a google query on a particular topic)

I don't think it's really appropriate to speak of design patterns with relational databases. Relational databases are already the application of a "design pattern" to a problem (the problem being "how to represent, store and work with data while maintaining its integrity", and the design being the relational model). Other approches (generally considered obsolete) are the Navigational and Hierarchical models (and I'm nure many others exist).

Having said that, you might consider "Data Warehousing" as a somewhat separate "pattern" or approach in database design. In particular, you might be interested in reading about the Star schema.

SQL selecting rows by most recent date with two unique columns

SELECT chargeId, chargeType, MAX(serviceMonth) AS serviceMonth 
FROM invoice
GROUP BY chargeId, chargeType

How to redirect output of an entire shell script within the script itself?

Addressing the question as updated.

#...part of script without redirection...

    #...part of script with redirection...
} > file1 2>file2 # ...and others as appropriate...

#...residue of script without redirection...

The braces '{ ... }' provide a unit of I/O redirection. The braces must appear where a command could appear - simplistically, at the start of a line or after a semi-colon. (Yes, that can be made more precise; if you want to quibble, let me know.)

You are right that you can preserve the original stdout and stderr with the redirections you showed, but it is usually simpler for the people who have to maintain the script later to understand what's going on if you scope the redirected code as shown above.

The relevant sections of the Bash manual are Grouping Commands and I/O Redirection. The relevant sections of the POSIX shell specification are Compound Commands and I/O Redirection. Bash has some extra notations, but is otherwise similar to the POSIX shell specification.

Remove HTML tags from string including &nbsp in C#

If you can't use an HTML parser oriented solution to filter out the tags, here's a simple regex for it.

string noHTML = Regex.Replace(inputHTML, @"<[^>]+>|&nbsp;", "").Trim();

You should ideally make another pass through a regex filter that takes care of multiple spaces as

string noHTMLNormalised = Regex.Replace(noHTML, @"\s{2,}", " ");

How to parse JSON boolean value?

Try this:

    "ACCOUNT_EXIST": true,
    "MultipleContacts": false

boolean success ((Boolean) jsonObject.get("ACCOUNT_EXIST")).booleanValue()

How to get text from EditText?

If you are doing it before the setContentView() method call, then the values will be null.

This will result in null:


Button btn = (Button)findViewById(;
String text = (String) btn.getText();


while this will work fine:


Button btn = (Button)findViewById(;
String text = (String) btn.getText();

Soft Edges using CSS?

You can use CSS gradient - although there are not consistent across browsers so You would have to code it for every one

Like that: CSS3 Transparency + Gradient

Gradient should be more transparent on top or on top right corner (depending on capabilities)

How to execute a Python script from the Django shell?

came here with the same question as the OP, and I found my favourite answer precisely in the mistake within the question, which works also in Python 3:

./ shell <<EOF
import my_script

How to change the order of DataFrame columns?

I think this is a slightly neater solution:

df.insert(0, 'mean', df.pop("mean"))

This solution is somewhat similar to @JoeHeffer 's solution but this is one liner.

Here we remove the column "mean" from the dataframe and attach it to index 0 with the same column name.

Intermediate language used in scalac?

The nearest equivalents would be icode and bcode as used by scalac, view Miguel Garcia's site on the Scalac optimiser for more information, here:

You might also consider Java bytecode itself to be your intermediate representation, given that bytecode is the ultimate output of scalac.

Or perhaps the true intermediate is something that the JIT produces before it finally outputs native instructions?

Ultimately though... There's no single place that you can point at an claim "there's the intermediate!". Scalac works in phases that successively change the abstract syntax tree, every single phase produces a new intermediate. The whole thing is like an onion, and it's very hard to try and pick out one layer as somehow being more significant than any other.

How to get value of checked item from CheckedListBox?

Egypt Development Blog : Get value of checked item in CheckedListBox in

after bind CheckedListBox with data you can get value of checked items

For i As Integer = 0 To CheckedListBox1.CheckedItems.Count - 1
                    Dim XDRV As DataRowView = CType(CheckedListBox1.CheckedItems(i), DataRowView)
                    Dim XDR As DataRow = XDRV.Row
                    Dim XDisplayMember As String = XDR(CheckedListBox1.DisplayMember).ToString()
                    Dim XValueMember As String = XDR(CheckedListBox1.ValueMember).ToString()
                    MsgBox("DisplayMember : " & XDisplayMember & "   - ValueMember : " & XValueMember )

now you can use the value or Display of checked items in CheckedListBox from the 2 variable XDisplayMember And XValueMember in the loop

hope to be useful.

Regex for empty string or white space

The \ (backslash) in the .match call is not properly escaped. It would be easier to use a regex literal though. Either will work:

var regex = "^\\s+$";
var regex = /^\s+$/;

Also note that + will require at least one space. You may want to use *.

Regex Match all characters between two strings

In case anyone is looking for an example of this within a Jenkins context. It parses the build.log and if it finds a match it fails the build with the match.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

        def file = readFile 'build.log'

        def regex = ~"(?s)(firstStringToUse(.*)secondStringToUse)"
        Matcher match = regex.matcher(file)
        match.find() {
            capturedText =

Getting path relative to the current working directory?

There is also a way to do this with some restrictions. This is the code from the article:

public string RelativePath(string absPath, string relTo)
        string[] absDirs = absPath.Split('\\');
        string[] relDirs = relTo.Split('\\');
        // Get the shortest of the two paths 
        int len = absDirs.Length < relDirs.Length ? absDirs.Length : relDirs.Length;
        // Use to determine where in the loop we exited 
        int lastCommonRoot = -1; int index;
        // Find common root 
        for (index = 0; index < len; index++)
            if (absDirs[index] == relDirs[index])
                lastCommonRoot = index;
            else break;
        // If we didn't find a common prefix then throw 
        if (lastCommonRoot == -1)
            throw new ArgumentException("Paths do not have a common base");
        // Build up the relative path 
        StringBuilder relativePath = new StringBuilder();
        // Add on the .. 
        for (index = lastCommonRoot + 1; index < absDirs.Length; index++)
            if (absDirs[index].Length > 0) relativePath.Append("..\\");
        // Add on the folders 
        for (index = lastCommonRoot + 1; index < relDirs.Length - 1; index++)
            relativePath.Append(relDirs[index] + "\\");
        relativePath.Append(relDirs[relDirs.Length - 1]);
        return relativePath.ToString();

When executing this piece of code:

string path1 = @"C:\Inetpub\wwwroot\Project1\Master\Dev\SubDir1"; 
string path2 = @"C:\Inetpub\wwwroot\Project1\Master\Dev\SubDir2\SubDirIWant";

System.Console.WriteLine (RelativePath(path1, path2));
System.Console.WriteLine (RelativePath(path2, path1));

it prints out:


Looking to understand the iOS UIViewController lifecycle

iOS 10,11 (Swift 3.1,Swift 4.0)

According to UIViewController in UIKit developers,

1. loadView()

This is where subclasses should create their custom view hierarchy if they aren't using a nib. Should never be called directly.

2. loadViewIfNeeded()

Loads the view controller's view if it has not already been set.

3. viewDidLoad()

Called after the view has been loaded. For view controllers created in code, this is after -loadView. For view controllers unarchived from a nib, this is after the view is set.

4. viewWillAppear(_ animated: Bool)

Called when the view is about to made visible. Default does nothing

5. viewWillLayoutSubviews()

Called just before the view controller's view's layoutSubviews method is invoked. Subclasses can implement as necessary. Default does nothing.

6. viewDidLayoutSubviews()

Called just after the view controller's view's layoutSubviews method is invoked. Subclasses can implement as necessary. Default does nothing.

7. viewDidAppear(_ animated: Bool)

Called when the view has been fully transitioned onto the screen. Default does nothing

8. viewWillDisappear(_ animated: Bool)

Called when the view is dismissed, covered or otherwise hidden. Default does nothing

9. viewDidDisappear(_ animated: Bool)

Called after the view was dismissed, covered or otherwise hidden. Default does nothing

10. viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator)

Called when the view is Transitioning.

11. willMove(toParentViewController parent: UIViewController?)

12. didMove(toParentViewController parent: UIViewController?)

These two methods are public for container subclasses to call when transitioning between child controllers. If they are overridden, the overrides should ensure to call the super.

The parent argument in both of these methods is nil when a child is being removed from its parent; otherwise it is equal to the new parent view controller.

13. didReceiveMemoryWarning()

Called when the parent application receives a memory warning. On iOS 6.0 it will no longer clear the view by default.

How to draw circle by canvas in Android?

    private Paint green = new Paint();

    private int greenx , greeny;




How can I determine whether a specific file is open in Windows?

If you right-click on your "Computer" (or "My Computer") icon and select "Manage" from the pop-up menu, that'll take you to the Computer Management console.

In there, under System Tools\Shared Folders, you'll find "Open Files". This is probably close to what you want, but if the file is on a network share then you'd need to do the same thing on the server on which the file lives.

How to get history on react-router v4?

If you are using redux and redux-thunk the best solution will be using react-router-redux

// then, in redux actions for example
import { push } from 'react-router-redux'


It's important to see the docs to do some configurations.

How to pass arguments to a Button command in Tkinter?

One simple way would be to configure button with lambda like the following syntax:

button['command'] = lambda arg1 = local_var1, arg2 = local_var2 : function(arg1, arg2)

How do I change the data type for a column in MySQL?

You use the alter table ... change ... method, for example:

mysql> create table yar (id int);
Query OK, 0 rows affected (0.01 sec)

mysql> insert into yar values(5);
Query OK, 1 row affected (0.01 sec)

mysql> alter table yar change id id varchar(255);
Query OK, 1 row affected (0.03 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> desc yar;
| Field | Type         | Null | Key | Default | Extra |
| id    | varchar(255) | YES  |     | NULL    |       |
1 row in set (0.00 sec)

MySQL 'create schema' and 'create database' - Is there any difference

Database is a collection of schemas and schema is a collection of tables. But in MySQL they use it the same way.

Adding background image to div using CSS

Specify a height and a width:

    background-image: url('../images/header-shade.jpg');
    height: 10px;
    width: 10px;

Set height 100% on absolute div

Few answers have given a solution with height and width 100% but I recommend you to not use percentage in css, use top/bottom and left/right positionning.

This is a better approach that allow you to control margin.

Here is the code :

body {
    position: relative;
    height: 3000px;
body div {

    bottom: 0px;
    right: 0px;
    background-color: yellow;
    position: absolute;

Is there a MySQL option/feature to track history of changes to records?

Just my 2 cents. I would create a solution which records exactly what changed, very similar to transient's solution.

My ChangesTable would simple be:

DateTime | WhoChanged | TableName | Action | ID |FieldName | OldValue

1) When an entire row is changed in the main table, lots of entries will go into this table, BUT that is very unlikely, so not a big problem (people are usually only changing one thing) 2) OldVaue (and NewValue if you want) have to be some sort of epic "anytype" since it could be any data, there might be a way to do this with RAW types or just using JSON strings to convert in and out.

Minimum data usage, stores everything you need and can be used for all tables at once. I'm researching this myself right now, but this might end up being the way I go.

For Create and Delete, just the row ID, no fields needed. On delete a flag on the main table (active?) would be good.

error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup

If you are having this problem and are using Qt - you need to link qtmain.lib or qtmaind.lib

Get OS-level system information

Have a look at the APIs available in the package. For example:

  • OperatingSystemMXBean.getSystemLoadAverage()
  • ThreadMXBean.getCurrentThreadCpuTime()
  • ThreadMXBean.getCurrentThreadUserTime()

There are loads of other useful things in there as well.

Simulate string split function in Excel formula

The following returns the first word in cell A1 when separated by a space (works in Excel 2003):

=LEFT(A1, SEARCH(" ",A1,1))

Changing the resolution of a VNC session in linux

I have a simple idea, something like this:


echo `xrandr --current | grep current | awk '{print $8}'` >> RES1
echo `xrandr --current | grep current | awk '{print $10}'` >> RES2
cat RES2 | sed -i 's/,//g' RES2

P1RES=$(cat RES1)
P2RES=$(cat RES2)
rm RES1 RES2
echo "$P1RES"'x'"$P2RES" >> RES
RES=$(cat RES)

# Play The Game

# Finish The Game with Lower Resolution

xrandr -s $RES

Well, I need a better solution for all display devices under Linux and Similars S.O

Printing tuple with string formatting in Python

You can try this one as well;

tup = (1,2,3)
print("this is a tuple {something}".format(something=tup))

You can't use %something with (tup) just because of packing and unpacking concept with tuple.

How to set socket timeout in C when making multiple connections?

You can use the SO_RCVTIMEO and SO_SNDTIMEO socket options to set timeouts for any socket operations, like so:

    struct timeval timeout;      
    timeout.tv_sec = 10;
    timeout.tv_usec = 0;

    if (setsockopt (sockfd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout,
                sizeof(timeout)) < 0)
        error("setsockopt failed\n");

    if (setsockopt (sockfd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout,
                sizeof(timeout)) < 0)
        error("setsockopt failed\n");

Edit: from the setsockopt man page:

SO_SNDTIMEO is an option to set a timeout value for output operations. It accepts a struct timeval parameter with the number of seconds and microseconds used to limit waits for output operations to complete. If a send operation has blocked for this much time, it returns with a partial count or with the error EWOULDBLOCK if no data were sent. In the current implementation, this timer is restarted each time additional data are delivered to the protocol, implying that the limit applies to output portions ranging in size from the low-water mark to the high-water mark for output.

SO_RCVTIMEO is an option to set a timeout value for input operations. It accepts a struct timeval parameter with the number of seconds and microseconds used to limit waits for input operations to complete. In the current implementation, this timer is restarted each time additional data are received by the protocol, and thus the limit is in effect an inactivity timer. If a receive operation has been blocked for this much time without receiving additional data, it returns with a short count or with the error EWOULDBLOCK if no data were received. The struct timeval parameter must represent a positive time interval; otherwise, setsockopt() returns with the error EDOM.

Execute Stored Procedure from a Function

Here is another possible workaround:

if exists (select * from master..sysservers where srvname = 'loopback')
    exec sp_dropserver 'loopback'
exec sp_addlinkedserver @server = N'loopback', @srvproduct = N'', @provider = N'SQLOLEDB', @datasrc = @@servername

create function testit()
    returns int
    declare @res int;
    select @res=count(*) from openquery(loopback, 'exec sp_who');
    return @res

select dbo.testit()

It's not so scary as xp_cmdshell but also has too many implications for practical use.

How to delete all the rows in a table using Eloquent?

In a similar vein to Travis vignon's answer, I required data from the eloquent model, and if conditions were correct, I needed to either delete or update the model. I wound up getting the minimum and maximum I'd field returned by my query (in case another field was added to the table that would meet my selection criteria) along with the original selection criteria to update the fields via one raw SQL query (as opposed to one eloquent query per object in the collection).

I know the use of raw SQL violates laravels beautiful code philosophy, but itd be hard to stomach possibly hundreds of queries in place of one.

iptables LOG and DROP in one rule

At work, I needed to log and block SSLv3 connections on ports 993 (IMAPS) and 995 (POP3S) using iptables. So, I combined Gert van Dijk's How to take down SSLv3 in your network using iptables firewall? (POODLE) with Prevok's answer and came up with this:

iptables -N SSLv3
iptables -A SSLv3 -j LOG --log-prefix "SSLv3 Client Hello detected: "
iptables -A SSLv3 -j DROP
iptables -A INPUT \
  -p tcp \! -f -m multiport --dports 993,995 \
  -m state --state ESTABLISHED -m u32 --u32 \
  "0>>22&0x3C@ 12>>26&0x3C@ 0 & 0xFFFFFF00=0x16030000 && \
   0>>22&0x3C@ 12>>26&0x3C@ 2 & 0xFF=0x01 && \
   0>>22&0x3C@ 12>>26&0x3C@ 7 & 0xFFFF=0x0300" \
  -j SSLv3


  1. To LOG and DROP, create a custom chain (e.g. SSLv3):

    iptables -N SSLv3
    iptables -A SSLv3 -j LOG --log-prefix "SSLv3 Client Hello detected: "
    iptables -A SSLv3 -j DROP
  2. Then, redirect what you want to LOG and DROP to that chain (see -j SSLv3):

    iptables -A INPUT \
      -p tcp \! -f -m multiport --dports 993,995 \
      -m state --state ESTABLISHED -m u32 --u32 \
      "0>>22&0x3C@ 12>>26&0x3C@ 0 & 0xFFFFFF00=0x16030000 && \
       0>>22&0x3C@ 12>>26&0x3C@ 2 & 0xFF=0x01 && \
       0>>22&0x3C@ 12>>26&0x3C@ 7 & 0xFFFF=0x0300" \
      -j SSLv3

Note: mind the order of the rules. Those rules did not work for me until I put them above this one I had on my firewall script:

iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

Get current user id in ASP.NET Identity 2.0

In order to get CurrentUserId in Identity 2.0, at first import Microsoft.AspNet.Identity:


using Microsoft.AspNet.Identity;


Imports Microsoft.AspNet.Identity

And then call User.Identity.GetUserId() everywhere you want:

strCurrentUserId = User.Identity.GetUserId()

This method returns current user id as defined datatype for userid in database (the default is String).

How do I compare two hashes?

I developed this to compare if two hashes are equal

def hash_equal?(hash1, hash2)
  array1 = hash1.to_a
  array2 = hash2.to_a
  (array1 - array2 | array2 - array1) == []

The usage:

> hash_equal?({a: 4}, {a: 4})
=> true
> hash_equal?({a: 4}, {b: 4})
=> false

> hash_equal?({a: {b: 3}}, {a: {b: 3}})
=> true
> hash_equal?({a: {b: 3}}, {a: {b: 4}})
=> false

> hash_equal?({a: {b: {c: {d: {e: {f: {g: {h: 1}}}}}}}}, {a: {b: {c: {d: {e: {f: {g: {h: 1}}}}}}}})
=> true
> hash_equal?({a: {b: {c: {d: {e: {f: {g: {marino: 1}}}}}}}}, {a: {b: {c: {d: {e: {f: {g: {h: 2}}}}}}}})
=> false

How to remove all the null elements inside a generic list in one go?

There is another simple and elegant option:


This will remove all elements that are not of type EmailParameterClass which will obviously filter out any elements of type null.

Here's a test:

class Test { }
class Program
    static void Main(string[] args)
        var list = new List<Test>();
        Console.WriteLine(list.OfType<Test>().Count());// 0
        list.Add(new Test());
        Console.WriteLine(list.OfType<Test>().Count());// 1
        Test test = null;
        Console.WriteLine(list.OfType<Test>().Count());// 1

ASP.NET file download from server

Making changes as below and redeploying on server content type as

Response.ContentType = "application/octet-stream";

This worked for me.

Response.AddHeader("Content-Disposition", "attachment; filename=" + file.Name); 
Response.AddHeader("Content-Length", file.Length.ToString()); 
Response.ContentType = "application/octet-stream"; 
Response.End(); in javascript

There is Array.filter():

var numbers = [1, 2, 3, 4, 5];
var filtered = numbers.filter(function(x) { return x > 3; });

// As a JavaScript 1.8 expression closure
filtered = numbers.filter(function(x) x > 3);

Note that Array.filter() is not standard ECMAScript, and it does not appear in ECMAScript specs older than ES5 (thanks Yi Jiang and jAndy). As such, it may not be supported by other ECMAScript dialects like JScript (on MSIE).

Nov 2020 Update: Array.filter is now supported across all major browsers.

How to set full calendar to a specific start date when it's initialized for the 1st time?

You should use the options 'year', 'month', and 'date' when initializing to specify the initial date value used by fullcalendar:

 year: 2012,
 month: 4,
 date: 25
});  // This will initialize for May 25th, 2012.

See the function setYMD(date,y,m,d) in the fullcalendar.js file; note that the JavaScript setMonth, setDate, and setFullYear functions are used, so your month value needs to be 0-based (Jan is 0).

UPDATE: As others have noted in the comments, the correct way now (V3 as of writing this edit) is to initialize the defaultDate property to a value that is

anything the Moment constructor accepts, including an ISO8601 date string like "2014-02-01"

as it uses Moment.js. Documentation here.

Updated example:

    defaultDate: "2012-05-25"
});  // This will initialize for May 25th, 2012.

How to set a cookie to expire in 1 hour in Javascript?

Code :

var now = new Date();
var time = now.getTime();
time += 3600 * 1000;
document.cookie = 
'username=' + value + 
'; expires=' + now.toUTCString() + 
'; path=/';

Single Form Hide on Startup

Put this in your Program.cs:

FormName FormName = new FormName ();

FormName.ShowInTaskbar = false;
FormName.Opacity = 0;

Use this when you want to display the form:

var principalForm = Application.OpenForms.OfType<FormName>().Single();
principalForm.ShowInTaskbar = true;
principalForm.Opacity = 100;

What is the effect of extern "C" in C++?

In every C++ program, all non-static functions are represented in the binary file as symbols. These symbols are special text strings that uniquely identify a function in the program.

In C, the symbol name is the same as the function name. This is possible because in C no two non-static functions can have the same name.

Because C++ allows overloading and has many features that C does not — like classes, member functions, exception specifications - it is not possible to simply use the function name as the symbol name. To solve that, C++ uses so-called name mangling, which transforms the function name and all the necessary information (like the number and size of the arguments) into some weird-looking string processed only by the compiler and linker.

So if you specify a function to be extern C, the compiler doesn't performs name mangling with it and it can be directly accessed using its symbol name as the function name.

This comes handy while using dlsym() and dlopen() for calling such functions.

How do I fix "for loop initial declaration used outside C99 mode" GCC error?

I've gotten this error too.

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

is not valid in the C89/C90 standard. As OysterD says, you need to do:

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

Your original code is allowed in C99 and later standards of the C language.

How to automatically start a service when running a docker container?

Simple! Add at the end of dockerfile:

ENTRYPOINT service mysql start && /bin/bash

How to encode URL parameters?

Using new ES6 Object.entries(), it makes for a fun little nested map/join:

const encodeGetParams = p => _x000D_
  Object.entries(p).map(kv =>"=")).join("&");_x000D_
const params = {_x000D_
  user: "María Rodríguez",_x000D_
  awesome: true,_x000D_
  awesomeness: 64,_x000D_
  "ZOMG+&=*(": "*^%*GMOZ"_x000D_
console.log("" + encodeGetParams(params))

Split string with delimiters in C

String tokenizer this code should put you in the right direction.

int main(void) {
  char st[] ="Where there is will, there is a way.";
  char *ch;
  ch = strtok(st, " ");
  while (ch != NULL) {
  printf("%s\n", ch);
  ch = strtok(NULL, " ,");
  return 0;

How can I create a war file of my project in NetBeans?

Right click your project, hit "Clean and Build". Netbeans does the rest.

under the dist directory of your app, you should find a pretty looking .war all ready for deployment.

select2 changing items dynamically

I fix the lack of example's library here:

<link href="" rel="stylesheet"/>
<script src="">

Align an element to bottom with flexbox

The solution with align-self: flex-end; didn't work for me but this one did in case you want to use flex:


|heading 1          |
|heading 2          | 
|paragraph text     |
|                   |
|                   |
|                   | 
|link button        |


Note: When "running the code snippet" you have to scroll down to see the link at the bottom.

.content {_x000D_
  display: flex;_x000D_
  justify-content: space-between;_x000D_
  flex-direction: column;_x000D_
  height: 300px;_x000D_
.content .upper {_x000D_
  justify-content: normal;_x000D_
/* Just to show container boundaries */_x000D_
.content .upper, .content .bottom, .content .upper > * {_x000D_
  border: 1px solid #ccc;_x000D_
<div class="content">_x000D_
  <div class="upper">_x000D_
   <h1>heading 1</h1>_x000D_
   <h2>heading 2</h2>_x000D_
   <p>paragraph text</p>_x000D_
  <div class="bottom">_x000D_
   <a href="/" class="button">link button</a>_x000D_

How can I list (ls) the 5 last modified files in a directory?

By default ls -t sorts output from newest to oldest, so the combination of commands to use depends in which direction you want your output to be ordered.

For the newest 5 files ordered from newest to oldest, use head to take the first 5 lines of output:

ls -t | head -n 5

For the newest 5 files ordered from oldest to newest, use the -r switch to reverse ls's sort order, and use tail to take the last 5 lines of output:

ls -tr | tail -n 5

The entity cannot be constructed in a LINQ to Entities query

only add AsEnumerable() :

public IQueryable<Product> GetProducts(int categoryID)
    return from p in db.Products.AsEnumerable()
           where p.CategoryID== categoryID
           select new Product { Name = p.Name};

Where to install Android SDK on Mac OS X?

I have been toying with this as well. I initially had it in my documents folder, but decided that didn't make 'philosophical' sense. I decided to create an Android directory in my home folder and place Eclipse and the Android SKK in there.

How to turn off the Eclipse code formatter for certain sections of Java code?

Not so pretty but works with default settings and for the first line as well:

String query = "" +
    "  FROM ABC          " +
    " WHERE BAR > 4      ";

how to bypass Access-Control-Allow-Origin?

It's a really bad idea to use *, which leaves you wide open to cross site scripting. You basically want your own domain all of the time, scoped to your current SSL settings, and optionally additional domains. You also want them all to be sent as one header. The following will always authorize your own domain in the same SSL scope as the current page, and can optionally also include any number of additional domains. It will send them all as one header, and overwrite the previous one(s) if something else already sent them to avoid any chance of the browser grumbling about multiple access control headers being sent.

class CorsAccessControl
    private $allowed = array();

     * Always adds your own domain with the current ssl settings.
    public function __construct()
        // Add your own domain, with respect to the current SSL settings.
        $this->allowed[] = 'http'
            . ( ( array_key_exists( 'HTTPS', $_SERVER )
                && $_SERVER['HTTPS'] 
                && strtolower( $_SERVER['HTTPS'] ) !== 'off' ) 
                    ? 's' 
                    : null )
            . '://' . $_SERVER['HTTP_HOST'];

     * Optionally add additional domains. Each is only added one time.
    public function add($domain)
        if ( !in_array( $domain, $this->allowed )
            $this->allowed[] = $domain;
     * Send 'em all as one header so no browsers grumble about it.
    public function send()
        $domains = implode( ', ', $this->allowed );
        header( 'Access-Control-Allow-Origin: ' . $domains, true ); // We want to send them all as one shot, so replace should be true here.


$cors = new CorsAccessControl();

// If you are only authorizing your own domain:

// If you are authorizing multiple domains:
foreach ($domains as $domain)

You get the idea.

How to commit and rollback transaction in sql server?

Don't use @@ERROR, use BEGIN TRY/BEGIN CATCH instead. See this article: Exception handling and nested transactions for a sample procedure:

create procedure [usp_my_procedure_name]
    set nocount on;
    declare @trancount int;
    set @trancount = @@trancount;
    begin try
        if @trancount = 0
            begin transaction
            save transaction usp_my_procedure_name;

        -- Do the actual work here

        if @trancount = 0   
    end try
    begin catch
        declare @error int, @message varchar(4000), @xstate int;
        select @error = ERROR_NUMBER(), @message = ERROR_MESSAGE(), @xstate = XACT_STATE();
        if @xstate = -1
        if @xstate = 1 and @trancount = 0
        if @xstate = 1 and @trancount > 0
            rollback transaction usp_my_procedure_name;

        raiserror ('usp_my_procedure_name: %d: %s', 16, 1, @error, @message) ;
    end catch   

How to select last child element in jQuery?

By using the :last-child selector?

Do you have a specific scenario in mind you need assistance with?

Attach Authorization header for all axios requests

The point is to set the token on the interceptors for each request

import axios from "axios";
const httpClient = axios.create({
    baseURL: "http://youradress",
    // baseURL: process.env.APP_API_BASE_URL,

httpClient.interceptors.request.use(function (config) {
    const token = localStorage.getItem('token');
    config.headers.Authorization =  token ? `Bearer ${token}` : '';
    return config;

Check if element is visible on screen

Could you use jQuery, since it's cross-browser compatible?

function isOnScreen(element)
    var curPos = element.offset();
    var curTop =;
    var screenHeight = $(window).height();
    return (curTop > screenHeight) ? false : true;

And then call the function using something like:

if(isOnScreen($('#myDivId'))) { /* Code here... */ };

Get last 5 characters in a string

Checks for errors:

Dim result As String = str
If str.Length > 5 Then
    result = str.Substring(str.Length - 5)
End If

How to remove array element in mongodb?

Try the following query:

  { _id: id },
  { $pull: { '': { number: '+1786543589455' } } }

It will find document with the given _id and remove the phone +1786543589455 from its array.

You can use $unset to unset the value in the array (set it to null), but not to remove it completely.

What exactly is std::atomic?

Each instantiation and full specialization of std::atomic<> represents a type that different threads can simultaneously operate on (their instances), without raising undefined behavior:

Objects of atomic types are the only C++ objects that are free from data races; that is, if one thread writes to an atomic object while another thread reads from it, the behavior is well-defined.

In addition, accesses to atomic objects may establish inter-thread synchronization and order non-atomic memory accesses as specified by std::memory_order.

std::atomic<> wraps operations that, in pre-C++ 11 times, had to be performed using (for example) interlocked functions with MSVC or atomic bultins in case of GCC.

Also, std::atomic<> gives you more control by allowing various memory orders that specify synchronization and ordering constraints. If you want to read more about C++ 11 atomics and memory model, these links may be useful:

Note that, for typical use cases, you would probably use overloaded arithmetic operators or another set of them:

std::atomic<long> value(0);
value++; //This is an atomic op
value += 5; //And so is this

Because operator syntax does not allow you to specify the memory order, these operations will be performed with std::memory_order_seq_cst, as this is the default order for all atomic operations in C++ 11. It guarantees sequential consistency (total global ordering) between all atomic operations.

In some cases, however, this may not be required (and nothing comes for free), so you may want to use more explicit form:

std::atomic<long> value {0};
value.fetch_add(1, std::memory_order_relaxed); // Atomic, but there are no synchronization or ordering constraints
value.fetch_add(5, std::memory_order_release); // Atomic, performs 'release' operation

Now, your example:

a = a + 12;

will not evaluate to a single atomic op: it will result in a.load() (which is atomic itself), then addition between this value and 12 and (also atomic) of final result. As I noted earlier, std::memory_order_seq_cst will be used here.

However, if you write a += 12, it will be an atomic operation (as I noted before) and is roughly equivalent to a.fetch_add(12, std::memory_order_seq_cst).

As for your comment:

A regular int has atomic loads and stores. Whats the point of wrapping it with atomic<>?

Your statement is only true for architectures that provide such guarantee of atomicity for stores and/or loads. There are architectures that do not do this. Also, it is usually required that operations must be performed on word-/dword-aligned address to be atomic std::atomic<> is something that is guaranteed to be atomic on every platform, without additional requirements. Moreover, it allows you to write code like this:

void* sharedData = nullptr;
std::atomic<int> ready_flag = 0;

// Thread 1
void produce()
    sharedData = generateData();, std::memory_order_release);

// Thread 2
void consume()
    while (ready_flag.load(std::memory_order_acquire) == 0)

    assert(sharedData != nullptr); // will never trigger

Note that assertion condition will always be true (and thus, will never trigger), so you can always be sure that data is ready after while loop exits. That is because:

  • store() to the flag is performed after sharedData is set (we assume that generateData() always returns something useful, in particular, never returns NULL) and uses std::memory_order_release order:


A store operation with this memory order performs the release operation: no reads or writes in the current thread can be reordered after this store. All writes in the current thread are visible in other threads that acquire the same atomic variable

  • sharedData is used after while loop exits, and thus after load() from flag will return a non-zero value. load() uses std::memory_order_acquire order:


A load operation with this memory order performs the acquire operation on the affected memory location: no reads or writes in the current thread can be reordered before this load. All writes in other threads that release the same atomic variable are visible in the current thread.

This gives you precise control over the synchronization and allows you to explicitly specify how your code may/may not/will/will not behave. This would not be possible if only guarantee was the atomicity itself. Especially when it comes to very interesting sync models like the release-consume ordering.

vertical-align: middle doesn't work

The answer given by Matt K works perfectly fine.

However it is important to note one thing - If the div you are applying it to has absolute positioning, it wont work. For it to work, do this -

<div style="position:absolute; hei...">
   <div style="position:relative; display: table-cell; vertical-align:middle; hei..."> 
      <!-- here position MUST be relative, this div acts as a wrapper-->

Getting the source HTML of the current page from chrome extension

Here is my solution:

chrome.runtime.onMessage.addListener(function(request, sender) {
        if (request.action == "getSource") {
            this.pageSource = request.source;
            var title = this.pageSource.match(/<title[^>]*>([^<]+)<\/title>/)[1];

    chrome.tabs.query({ active: true, currentWindow: true }, tabs => {
            { code: 'var s = document.documentElement.outerHTML; chrome.runtime.sendMessage({action: "getSource", source: s});' }

How to Decode Json object in laravel and apply foreach loop on that in laravel

your string is NOT a valid json to start with.

a valid json will be,

    "area": [
            "area": "kothrud"
            "area": "katraj"

if you do a json_decode, it will yield,

stdClass Object
    [area] => Array
            [0] => stdClass Object
                    [area] => kothrud

            [1] => stdClass Object
                    [area] => katraj



Update: to use

$string = '

    "area": [
            "area": "kothrud"
            "area": "katraj"

            $area = json_decode($string, true);

            foreach($area['area'] as $i => $v)
                echo $v['area'].'<br/>';



Update #2:

for that true:

When TRUE, returned objects will be converted into associative arrays. for more information, click here

make iframe height dynamic based on content inside- JQUERY/Javascript

you could also add a repeating requestAnimationFrame to your resizeIframe (e.g. from @BlueFish's answer) which would always be called before the browser paints the layout and you could update the height of the iframe when its content have changed their heights. e.g. input forms, lazy loaded content etc.

<script type="text/javascript">
  function resizeIframe(iframe) {
    iframe.height = iframe.contentWindow.document.body.scrollHeight + "px";
    window.requestAnimationFrame(() => resizeIframe(iframe));

<iframe onload="resizeIframe(this)" ...

your callback should be fast enough to have no big impact on your overall performance

How to pass a PHP variable using the URL

I found this solution in "Super useful bits of PHP, Form and JavaScript code" at Skytopia.

Inside "page1.php" or "page1.html":

// Send the variables myNumber=1 and myFruit="orange" to the new PHP page...
<a href="page2c.php?myNumber=1&myFruit=orange">Send variables via URL!</a> 

    //or as I needed it.
    <a href='page2c.php?myNumber={$row[0]}&myFruit={$row[1]}'>Send variables</a>

Inside "page2c.php":

    // Retrieve the URL variables (using PHP).
    $num = $_GET['myNumber'];
    $fruit = $_GET['myFruit'];
    echo "Number: ".$num."  Fruit: ".$fruit;

Write Base64-encoded image to file

No need to use BufferedImage, as you already have the image file in a byte array

    byte dearr[] = Base64.decodeBase64(crntImage);
    FileOutputStream fos = new FileOutputStream(new File("c:/decode/abc.bmp")); 

Most Pythonic way to provide global configuration variables in

How about using classes?

class MYSQL:
    PORT = 3306
    DATABASE = 'mydb'
    DATABASE_TABLES = ['tb_users', 'tb_groups']

from config import MYSQL

print(MYSQL.PORT) # 3306

How do I wait for a promise to finish before returning the variable of a function?

You don't want to make the function wait, because JavaScript is intended to be non-blocking. Rather return the promise at the end of the function, then the calling function can use the promise to get the server response.

var promise = query.find(); 
return promise; 

//Or return query.find(); 

Cannot open include file: 'unistd.h': No such file or directory

If you're using ZLib in your project, then you need to find :

#if 1

in zconf.h and replace(uncomment) it with :

#if HAVE_UNISTD_H /* ...the rest of the line

If it isn't ZLib I guess you should find some alternative way to do this. GL.

Best Practice for Forcing Garbage Collection in C#

Look at it this way - is it more efficient to throw out the kitchen garbage when the garbage can is at 10% or let it fill up before taking it out?

By not letting it fill up, you are wasting your time walking to and from the garbage bin outside. This analogous to what happens when the GC thread runs - all the managed threads are suspended while it is running. And If I am not mistaken, the GC thread can be shared among multiple AppDomains, so garbage collection affects all of them.

Of course, you might encounter a situation where you won't be adding anything to the garbage can anytime soon - say, if you're going to take a vacation. Then, it would be a good idea to throw out the trash before going out.

This MIGHT be one time that forcing a GC can help - if your program idles, the memory in use is not garbage-collected because there are no allocations.

Change remote repository credentials (authentication) on Intellij IDEA 14

  1. Go to [project]/.git directory.
  2. Open for edit 'config' file.
  3. In '[remote "origin"]' section find 'url' property and replace your old password with new one.
  4. Press Ctrl+T in Intellij IDEA to update project.

BAT file to open CMD in current directory

you probably want to do this:

cd /d %~dp0

this will set your current directory to the directory you have the batch file in

Overriding fields or properties in subclasses

You could define something like this:

abstract class Father
    //Do you need it public?
    protected readonly int MyInt;

class Son : Father
    public Son()
        MyInt = 1;

By setting the value as readonly, it ensures that the value for that class remains unchanged for the lifetime of the object.

I suppose the next question is: why do you need it?

querySelector, wildcard element match?

[id^='someId'] will match all ids starting with someId.

[id$='someId'] will match all ids ending with someId.

[id*='someId'] will match all ids containing someId.

If you're looking for the name attribute just substitute id with name.

If you're talking about the tag name of the element I don't believe there is a way using querySelector

How to redirect verbose garbage collection output to a file?

To add to the above answers, there's a good article: Useful JVM Flags – Part 8 (GC Logging) by Patrick Peschlow.

A brief excerpt:

The flag -XX:+PrintGC (or the alias -verbose:gc) activates the “simple” GC logging mode

By default the GC log is written to stdout. With -Xloggc:<file> we may instead specify an output file. Note that this flag implicitly sets -XX:+PrintGC and -XX:+PrintGCTimeStamps as well.

If we use -XX:+PrintGCDetails instead of -XX:+PrintGC, we activate the “detailed” GC logging mode which differs depending on the GC algorithm used.

With -XX:+PrintGCTimeStamps a timestamp reflecting the real time passed in seconds since JVM start is added to every line.

If we specify -XX:+PrintGCDateStamps each line starts with the absolute date and time.

How to increase memory limit for PHP over 2GB?

Have you tried using the value in MB ?

php_value memory_limit 2048M

Also try editing this value in php.ini not Apache.

Null pointer Exception on .setOnClickListener

android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference

Because Submit button is inside login_modal so you need to use loginDialog view to access button:

Submit = (Button)loginDialog.findViewById(;

How to split (chunk) a Ruby array into parts of X elements?

If you're using rails you can also use in_groups_of:


MySQL foreach alternative for procedure

Here's the mysql reference for cursors. So I'm guessing it's something like this:

  DECLARE products_id INT;
  DECLARE result varchar(4000);
  DECLARE cur1 CURSOR FOR SELECT products_id FROM sets_products WHERE set_id = 1;

  OPEN cur1;

    FETCH cur1 INTO products_id;
    IF NOT done THEN
      CALL generate_parameter_list(@product_id, @result);
      SET param = param + "," + result; -- not sure on this syntax
    END IF;

  CLOSE cur1;

  -- now trim off the trailing , if desired

Import multiple csv files into pandas and concatenate into one DataFrame

The Dask library can read a dataframe from multiple files:

>>> import dask.dataframe as dd
>>> df = dd.read_csv('data*.csv')


The Dask dataframes implement a subset of the Pandas dataframe API. If all the data fits into memory, you can call df.compute() to convert the dataframe into a Pandas dataframe.

How can I print the contents of a hash in Perl?

If you want to be pedantic and keep it to one line (without use statements and shebang), then I'll sort of piggy back off of tetromino's answer and suggest:

print Dumper( { 'abc' => 123, 'def' => [4,5,6] } );

Not doing anything special other than using the anonymous hash to skip the temp variable ;)

variable is not declared it may be inaccessible due to its protection level

This error occurred for me when I mistakenly added a comment following a line continuation character in VB.Net. I removed the comment and the problem went away.

Excel "External table is not in the expected format."

the file might be locked by another process, you need to copy it then load it as it says in this post

How to POST request using RestSharp

I added this helper method to handle my POST requests that return an object I care about.

For REST purists, I know, POSTs should not return anything besides a status. However, I had a large collection of ids that was too big for a query string parameter.

Helper Method:

    public TResponse Post<TResponse>(string relativeUri, object postBody) where TResponse : new()
        //Note: Ideally the RestClient isn't created for each request. 
        var restClient = new RestClient("http://localhost:999");

        var restRequest = new RestRequest(relativeUri, Method.POST)
            RequestFormat = DataFormat.Json


        var result = restClient.Post<TResponse>(restRequest);

        if (!result.IsSuccessful)
            throw new HttpException($"Item not found: {result.ErrorMessage}");

        return result.Data;


    public List<WhateverReturnType> GetFromApi()
        var idsForLookup = new List<int> {1, 2, 3, 4, 5};

        var relativeUri = "/api/idLookup";

        var restResponse = Post<List<WhateverReturnType>>(relativeUri, idsForLookup);

        return restResponse;

How do I show the value of a #define at compile-time?

Are you looking for

#if BOOST_VERSION != "1.2"
#error "Bad version"

Not great if BOOST_VERSION is a string, like I've assumed, but there may also be individual integers defined for the major, minor and revision numbers.

How to convert string to boolean in typescript Angular 4

Define extension: String+Extension.ts

interface String {
  toBoolean(): boolean

String.prototype.toBoolean = function (): boolean {
  switch (this) {
    case 'true':
    case '1':
    case 'on':
    case 'yes':
      return true
      return false

And import in any file where you want to use it '@/path/to/String+Extension'

VBScript to send email without running Outlook

You can send email without Outlook in VBScript using the CDO.Message object. You will need to know the address of your SMTP server to use this:

Set MyEmail=CreateObject("CDO.Message")

MyEmail.From="[email protected]"
MyEmail.To="[email protected]"
MyEmail.TextBody="Testing one two three."

MyEmail.Configuration.Fields.Item ("")=2

'SMTP Server
MyEmail.Configuration.Fields.Item ("")=""

'SMTP Port
MyEmail.Configuration.Fields.Item ("")=25 


set MyEmail=nothing

If your SMTP server requires a username and password then paste these lines in above the MyEmail.Configuration.Fields.Update line:

'SMTP Auth (For Windows Auth set this to 2)
MyEmail.Configuration.Fields.Item ("")=1
MyEmail.Configuration.Fields.Item ("")="username" 
MyEmail.Configuration.Fields.Item ("")="password"

More information on using CDO to send email with VBScript can be found on the link below:

Which Android IDE is better - Android Studio or Eclipse?

From the Android Studio download page:

Caution: Android Studio is currently available as an early access preview. Several features are either incomplete or not yet implemented and you may encounter bugs. If you are not comfortable using an unfinished product, you may want to instead download (or continue to use) the ADT Bundle (Eclipse with the ADT Plugin).

How to change the text on the action bar

The Easiest way to change the action bar name is to go to the AndroidManifest.xml and type this code.

<activity android:name=".MainActivity"
    android:label="Your Label> </activity>

How to list npm user-installed packages?

As of 13 December 2015

npm list illustration

Whilst I found the accepted answer 100% correct, and useful, wished to expand upon it a little based on my own experiences, and hopefully for the benefit of others too. (Here I am using the terms package and module interchangeably)

In answer to the question, yes the accepted answer would be:

npm list -g --depth=0

You might wish to check for a particular module installed globally, on *nix systems / when grep available. This is particularly useful when checking what version of a module you are using (globally installed, just remove the -g flag if checking a local module):

npm list -g --depth=0 | grep <module_name>

If you'd like to see all available (remote) versions for a particular module, then do:

npm view <module_name> versions

Note, versions is plural. This will give you the full listing of versions to choose from.

For latest remote version:

npm view <module_name> version  

Note, version is singular.

To find out which packages need to be updated, you can use

npm outdated -g --depth=0

To update global packages, you can use

npm update -g <package>

To update all global packages, you can use:

npm update -g

(However, for npm versions less than 2.6.1, please also see this link as there is a special script that is recommended for globally updating all packages).

The above commands should work across NPM versions 1.3.x, 1.4.x, 2.x and 3.x

Exiting from python Command Line

In my python interpreter exit is actually a string and not a function -- 'Use Ctrl-D (i.e. EOF) to exit.'. You can check on your interpreter by entering type(exit)

In active python what is happening is that exit is a function. If you do not call the function it will print out the string representation of the object. This is the default behaviour for any object returned. It's just that the designers thought people might try to type exit to exit the interpreter, so they made the string representation of the exit function a helpful message. You can check this behaviour by typing str(exit) or even print exit.

How to add label in chart.js for pie chart

Use ChartNew.js instead of Chart.js


So, I have re-worked Chart.js. Most of the changes, are associated to requests in "GitHub" issues of Chart.js.

And here is a sample

var newopts = {
    inGraphDataShow: true,
    inGraphDataRadiusPosition: 2,
    inGraphDataFontColor: 'white'
var pieData = [
        value: 30,
        color: "#F38630",
       value: 30,
       color: "#F34353",
        value: 30,
        color: "#F34353",
var pieCtx = document.getElementById('pieChart').getContext('2d');
new Chart(pieCtx).Pie(pieData, newopts);

It even provides a GUI editor

So sweet.

jQuery date formatting

Though this question was asked a few years ago, a jQuery plugin isn't required anymore provided the date value in question is a string with format mm/dd/yyyy (like when using a date-picker);

var birthdateVal = $('#birthdate').val();
//birthdateVal: 11/8/2014

var birthdate = new Date(birthdateVal);
//birthdate: Sat Nov 08 2014 00:00:00 GMT-0500 (Eastern Standard Time)

How do I get the directory of the PowerShell script I execute?

PowerShell 3 has the $PSScriptRoot automatic variable:

Contains the directory from which a script is being run.

In Windows PowerShell 2.0, this variable is valid only in script modules (.psm1). Beginning in Windows PowerShell 3.0, it is valid in all scripts.

Don't be fooled by the poor wording. PSScriptRoot is the directory of the current file.

In PowerShell 2, you can calculate the value of $PSScriptRoot yourself:

# PowerShell v2
$PSScriptRoot = Split-Path -Parent -Path $MyInvocation.MyCommand.Definition

The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>)

For those using Telerik as mentioned by Ovar, make sure you wrap your javascript in

 <telerik:RadScriptBlock ID="radSript1" runat="server">
   <script type="text/javascript">
        //Your javascript

Since Telerik doesn't recognize <%# %> when looking for an element and <%= %> will give you an error if your javascript code isn't wrapped.

WPF chart controls

Sparrow Chart Toolkit a best opensource chart control for multiple platforms
-Windows phone
-Windows Forms

pip or pip3 to install packages for Python 3?

In my system, I use the update alternatives.

sudo update-alternatives --install /usr/bin/pip pip /usr/bin/pip3 1
sudo update-alternatives --install /usr/bin/pip pip /usr/bin/pip2 2

If I want to switch between them I use the following command.

sudo update-alternatives --config pip

Note: The 1st line is enough if you have only pip3 installed and not pip2.

Line break in SSRS expression

You should NOT quote your Environment.NewLine man. Try "Your Text" & Environment.NewLine.

Copy mysql database from remote server to local computer

Often our databases are really big and the take time to take dump directly from remote machine to other machine as our friends other have suggested above.

In such cases what you can do is to take the dump on remote machine using MYSQLDUMP Command

MYSQLDUMP -uuser -p --all-databases > file_name.sql

and than transfer that file from remote server to your machine using Linux SCP Command

scp user@remote_ip:~/mysql_dump_file_name.sql ./

How to center form in bootstrap 3

<div class="col-md-4 offset-md-4"> 
put your form here

In Java how does one turn a String into a char or a char into a String?

String someString = "" + c;
char c = someString.charAt(0);

How to remove all subviews of a view in Swift?

In xcodebeta6 this worked out.

    var subViews = self.parentView.subviews
    for subview in subViews as [UIView]   {

ArrayList or List declaration in Java

Possibly you can refer to this link

List is an interface.ArrayList,LinkedList etc are classes which implement list.Whenyou are using List Interface,you have to itearte elements using ListIterator and can move forward and backward,in the List where as in ArrayList Iterate using Iterator and its elements can be accessed unidirectional way.

Java, How to specify absolute value and square roots

int currentNum = 5;
double sqrRoot = 0.0;
int sqrRootInt = 0;

sqrRootInt= (int)sqrRoot;

Redirecting to a certain route based on condition

If you do not want to use angular-ui-router, but would like to have your controllers lazy loaded via RequireJS, there are couple of problems with event $routeChangeStart when using your controllers as RequireJS modules (lazy loaded).

You cannot be sure the controller will be loaded before $routeChangeStart gets triggered -- in fact it wont be loaded. That means you cannot access properties of next route like locals or $$route because they are not yet setup.

app.config(["$routeProvider", function($routeProvider) {
    $routeProvider.when("/foo", {
        controller: "Foo",
        resolve: {
            controller: ["$q", function($q) {
                var deferred = $q.defer();
                require(["path/to/controller/Foo"], function(Foo) {
                    // now controller is loaded
                return deferred.promise;
}]);["$rootScope", function($rootScope) {
    $rootScope.$on("$routeChangeStart", function(event, next, current) {
        console.log(next.$$route, next.locals); // undefined, undefined

This means you cannot check access rights in there.


As loading of controller is done via resolve, you can do the same with your access control check:

app.config(["$routeProvider", function($routeProvider) {
    $routeProvider.when("/foo", {
        controller: "Foo",
        resolve: {
            controller: ["$q", function($q) {
                var deferred = $q.defer();
                require(["path/to/controller/Foo"], function(Foo) {
                    // now controller is loaded
                return deferred.promise;
            access: ["$q", function($q) {
                var deferred = $q.defer();
                if (/* some logic to determine access is granted */) {
                } else {
                    deferred.reject("You have no access rights to go there");
                return deferred.promise;
}]);["$rootScope", function($rootScope) {
    $rootScope.$on("$routeChangeError", function(event, next, current, error) {
        console.log("Error: " + error); // "Error: You have no access rights to go there"

Note here that instead of using event $routeChangeStart I'm using $routeChangeError

JavaScript/JQuery: $(window).resize how to fire AFTER the resize is completed?

Many thanks to David Walsh, here is a vanilla version of underscore debounce.


// Returns a function, that, as long as it continues to be invoked, will not
// be triggered. The function will be called after it stops being called for
// N milliseconds. If `immediate` is passed, trigger the function on the
// leading edge, instead of the trailing.
function debounce(func, wait, immediate) {
    var timeout;
    return function() {
        var context = this, args = arguments;
        var later = function() {
            timeout = null;
            if (!immediate) func.apply(context, args);
        var callNow = immediate && !timeout;
        timeout = setTimeout(later, wait);
        if (callNow) func.apply(context, args);

Simple usage:

var myEfficientFn = debounce(function() {
    // All the taxing stuff you do
}, 250);

$(window).on('resize', myEfficientFn);


Where to find the complete definition of off_t type?

Since this answer still gets voted up, I want to point out that you should almost never need to look in the header files. If you want to write reliable code, you're much better served by looking in the standard. A better question than "how is off_t defined on my machine" is "how is off_t defined by the standard?". Following the standard means that your code will work today and tomorrow, on any machine.

In this case, off_t isn't defined by the C standard. It's part of the POSIX standard, which you can browse here.

Unfortunately, off_t isn't very rigorously defined. All I could find to define it is on the page on sys/types.h:

blkcnt_t and off_t shall be signed integer types.

This means that you can't be sure how big it is. If you're using GNU C, you can use the instructions in the answer below to ensure that it's 64 bits. Or better, you can convert to a standards defined size before putting it on the wire. This is how projects like Google's Protocol Buffers work (although that is a C++ project).

So, I think "where do I find the definition in my header files" isn't the best question. But, for completeness here's the answer:

On my machine (and most machines using glibc) you'll find the definition in bits/types.h (as a comment says at the top, never directly include this file), but it's obscured a bit in a bunch of macros. An alternative to trying to unravel them is to look at the preprocessor output:

#include <stdio.h>
#include <sys/types.h>

int main(void) {
  off_t blah;

  return 0;

And then:

$ gcc -E sizes.c  | grep __off_t
typedef long int __off_t;

However, if you want to know the size of something, you can always use the sizeof() operator.

Edit: Just saw the part of your question about the __. This answer has a good discussion. The key point is that names starting with __ are reserved for the implementation (so you shouldn't start your own definitions with __).

I ran into a merge conflict. How can I abort the merge?


Because you not commit your merge, then just double click on another branch (which mean checkout it) and when sourcetree ask you about discarding all changes then agree :)


I see many down-votes but any commet... I will left this answer which is addressed for those who use SourceTree as git client (as I - when I looking for solution for question asked by OP)

How do I jump to a closing bracket in Visual Studio Code?

i use End key, but. as you said you found a way to solve this problem in sublime text... right????

i will suggest you to install keymap of sublime text .. here and use that sortcut key to solve your same problem in vscode.

how to install
press -> ctrl + k then ctrl + M

or watch the bottom left corner there is a gear called setting click on theat you will found keymaps you will redirected to the extentions were you will have to choose your ex-editor..

Issue with background color and Google Chrome

Google Chrome and safari needs a tweak for body and background issues. We have use additional identifier as mentioned below.

body { background:#204960 url(../images/example.gif) repeat-x top; margin:0; padding:0; font-family:Tahoma; font-size:12px; }

#body{ background:#204960 url(../images/example.gif) repeat-x top; margin:0; padding:0; font-family:Tahoma; font-size:12px;}
<body id="body">

Use both body and #body identifier and enter same styles in both. Make the body tag with id attribute of body.

This works for me.

jQuery pass more parameters into callback

In today's world there is a another answer that is cleaner, and taken from another Stack Overflow answer:

function clicked()
    var myDiv = $( "#my-div" );

    $.post( "someurl.php", {"someData": someData}, $.proxy(doSomething, myDiv), "json" );

function doSomething( data )
    // this will be equal to myDiv now. Thanks to jQuery.proxy().
    var $myDiv = this;

    // doing stuff.

Here's the original question and answer: jQuery HOW TO?? pass additional parameters to success callback for $.ajax call?

How to set JAVA_HOME environment variable on Mac OS X 10.9?

In Mac OSX 10.5 or later, Apple recommends to set the $JAVA_HOME variable to /usr/libexec/java_home, just export $JAVA_HOME in file ~/. bash_profile or ~/.profile.

Open the terminal and run the below command.

$ vim .bash_profile

export JAVA_HOME=$(/usr/libexec/java_home)

save and exit from vim editor, then run the source command on .bash_profile

$ source .bash_profile

$ echo $JAVA_HOME


Can not get a simple bootstrap modal to work

I had an issue with Modals as well. I should have declare jquery.min.js before bootstrap.min.js (in my layout page). From official site : "all plugins depend on jQuery (this means jQuery must be included before the plugin files)"

Accessing a Dictionary.Keys Key through a numeric index

One alternative would be a KeyedCollection if the key is embedded in the value.

Just create a basic implementation in a sealed class to use.

So to replace Dictionary<string, int> (which isn't a very good example as there isn't a clear key for a int).

private sealed class IntDictionary : KeyedCollection<string, int>
    protected override string GetKeyForItem(int item)
        // The example works better when the value contains the key. It falls down a bit for a dictionary of ints.
        return item.ToString();

KeyedCollection<string, int> intCollection = new ClassThatContainsSealedImplementation.IntDictionary();


int valueByIndex = intCollection[0];

Redeploy alternatives to JRebel

DCEVM supports enhanced class redefinitions and is available for current JDK7 and JDK8.

HotswapAgent is an free JRebel alternative and supports DCEVM in various Frameworks.

Python strip() multiple characters?

I did a time test here, using each method 100000 times in a loop. The results surprised me. (The results still surprise me after editing them in response to valid criticism in the comments.)

Here's the script:

import timeit

bad_chars = '(){}<>'

setup = """import re
import string
s = 'Barack (of Washington)'
bad_chars = '(){}<>'
rgx = re.compile('[%s]' % bad_chars)"""

timer = timeit.Timer('o = "".join(c for c in s if c not in bad_chars)', setup=setup)
print "List comprehension: ",  timer.timeit(100000)

timer = timeit.Timer("o= rgx.sub('', s)", setup=setup)
print "Regular expression: ", timer.timeit(100000)

timer = timeit.Timer('for c in bad_chars: s = s.replace(c, "")', setup=setup)
print "Replace in loop: ", timer.timeit(100000)

timer = timeit.Timer('s.translate(string.maketrans("", "", ), bad_chars)', setup=setup)
print "string.translate: ", timer.timeit(100000)

Here are the results:

List comprehension:  0.631745100021
Regular expression:  0.155561923981
Replace in loop:  0.235936164856
string.translate:  0.0965719223022

Results on other runs follow a similar pattern. If speed is not the primary concern, however, I still think string.translate is not the most readable; the other three are more obvious, though slower to varying degrees.

Maven: How to include jars, which are not available in reps into a J2EE project?

you can install them in a private, local repository (e.g. .m2/repository under your home directory): more details here

Page Redirect after X seconds wait using JavaScript

setTimeout('Redirect()', 1000);
function Redirect() 

//document.write("You will be Redirect to a new page in 1000 -> 1 Seconds, 2000 -> 2 Seconds");

Comment out HTML and PHP together

Instead of using HTML comments (which have no effect on PHP code -- which will still be executed), you should use PHP comments:

<?php /*
      <td><?php echo $entry_keyword; ?></td>
      <td><input type="text" name="keyword" value="<?php echo $keyword; ?>" /></td>
      <td><?php echo $entry_sort_order; ?></td>
      <td><input name="sort_order" value="<?php echo $sort_order; ?>" size="1" /></td>
*/ ?>

With that, the PHP code inside the HTML will not be executed; and nothing (not the HTML, not the PHP, not the result of its non-execution) will be displayed.

Just one note: you cannot nest C-style comments... which means the comment will end at the first */ encountered.

Ruby on Rails generates model field:type - what are the options for field:type?

There are lots of data types you can mention while creating model, some examples are:

:primary_key, :string, :text, :integer, :float, :decimal, :datetime, :timestamp, :time, :date, :binary, :boolean, :references



Error:Execution failed for task ':app:dexDebug'.

For me I had multiple versions of the same library included in /app/libs. I was using Parse and I had both ParseFacebookUtilsV3-1.9.0.jar and ParseFacebookUtilsV4-1.9.0.jar.

Deleting the V3 jar solves the problem.

Nested or Inner Class in PHP

Put each class into separate files and "require" them.



    class User {

        public $userid;
        public $username;
        private $password;
        public $profile;
        public $history;            

        public function __construct() {


            $this->profile = new UserProfile();
            $this->history = new UserHistory();






    class UserProfile 
        // Some code here




    class UserHistory 
        // Some code here


How to check Elasticsearch cluster health?

The _cluster/health API can do far more than the typical output that most see with it:

 $ curl -XGET 'localhost:9200/_cluster/health?pretty'

Most APIs within Elasticsearch can take a variety of arguments to augment their output. This applies to Cluster Health API as well.


all the indices health
$ curl -XGET 'localhost:9200/_cluster/health?level=indices&pretty' | head -50
  "cluster_name" : "rdu-es-01",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 9,
  "number_of_data_nodes" : 6,
  "active_primary_shards" : 1106,
  "active_shards" : 2213,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 100.0,
  "indices" : {
    "filebeat-6.5.1-2019.06.10" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    "filebeat-6.5.1-2019.06.11" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    "filebeat-6.5.1-2019.06.12" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    "filebeat-6.5.1-2019.06.13" : {
      "status" : "green",
      "number_of_shards" : 3,
all shards health
$ curl -XGET 'localhost:9200/_cluster/health?level=shards&pretty' | head -50
  "cluster_name" : "rdu-es-01",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 9,
  "number_of_data_nodes" : 6,
  "active_primary_shards" : 1106,
  "active_shards" : 2213,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 100.0,
  "indices" : {
    "filebeat-6.5.1-2019.06.10" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0,
      "shards" : {
        "0" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0
        "1" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0
        "2" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0

The API also has a variety of wait_* options where it'll wait for various state changes before returning immediately or after some specified timeout.

How to serialize Object to JSON?

You make the http request

HttpResponse response = httpclient.execute(httpget);           
HttpEntity entity = response.getEntity();

inputStream = entity.getContent();

BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
            StringBuilder sb = new StringBuilder();

You read the Buffer

String line = null;
while ((line = reader.readLine()) != null)
sb.append(line + "\n");
Log.d("Result", sb.toString());
result = sb.toString();

Create a JSONObject and pass the result string to the constructor:

JSONObject json = new JSONObject(result);

Parse the json results to your desired variables:

String usuario= json.getString("usuario");
int idperon = json.getInt("idperson");
String nombre = json.getString("nombre");

Do not forget to import:

import org.json.JSONObject;

How do I center text horizontally and vertically in a TextView?

You can also set it up dynamically using:

textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.CENTER_HORIZONTAL);

Laravel 4 Eloquent Query Using WHERE with OR AND OR?

if you want to use parentheses in laravel 4 and don't forget return
In Laravel 4 (at least) you need to use $a, $b in parentheses as in the example

$a = 1;
$b = 1;
$c = 1;
$d = 1;
Model::where(function ($query) use ($a, $b) {
    return $query->where('a', '=', $a)
          ->orWhere('b', '=', $b);
})->where(function ($query) use ($c, $d) {
    return $query->where('c', '=', $c)
          ->orWhere('d', '=', $d);

This is my result: enter image description here

Command failed due to signal: Segmentation fault: 11

I had that code 11 when trying to build for release scheme. It pointed out one viewcontroller class (swift) that had this piece of code inside:

 required init(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)

The problem was that when I have added superclass to it, I forgot to also implement init. So that super.init caused compiler error Segmentation fault: 11 So if you have such problem it's good idea to check also any superclasses.

How do I put a clear button inside my HTML text input box like the iPhone does?

@Mahmoud Ali Kaseem

I have just changed some CSS to make it look different and added focus();

$('#clear').click(function() {_x000D_
  $('#input-outer input').val('');_x000D_
  $('#input-outer input').focus();_x000D_
body {_x000D_
  font-family: "Arial";_x000D_
  font-size: 14px;_x000D_
#input-outer {_x000D_
  height: 2em;_x000D_
  width: 15em;_x000D_
  border: 1px #777 solid;_x000D_
  position: relative;_x000D_
  padding: 0px;_x000D_
  border-radius: 4px;_x000D_
#input-outer input {_x000D_
  height: 100%;_x000D_
  width: 100%;_x000D_
  border: 0px;_x000D_
  outline: none;_x000D_
  margin: 0 0 0 0px;_x000D_
  color: #666;_x000D_
  box-sizing: border-box;_x000D_
  padding: 5px;_x000D_
  padding-right: 35px;_x000D_
  border-radius: 4px;_x000D_
#clear {_x000D_
  position: absolute;_x000D_
  float: right;_x000D_
  height: 2em;_x000D_
  width: 2em;_x000D_
  top: 0px;_x000D_
  right: 0px;_x000D_
  background: #aaa;_x000D_
  color: white;_x000D_
  text-align: center;_x000D_
  cursor: pointer;_x000D_
  border-radius: 0px 4px 4px 0px;_x000D_
#clear:after {_x000D_
  content: "\274c";_x000D_
  position: absolute;_x000D_
  top: 4px;_x000D_
  right: 7px;_x000D_
#clear:focus {_x000D_
  background: #888;_x000D_
#clear:active {_x000D_
  background: #666;_x000D_
<script src=""></script>_x000D_
<div id="input-outer">_x000D_
  <input type="text">_x000D_
  <div id="clear"></div>_x000D_

Regular expression for checking if capital letters are found consecutively in a string?

Whenever one writes [A-Z] or [a-z], one explicitly commits to processing nothing but 7-bit ASCII data from the 1960s. If that’s really ok, then fine. But if it’s not ok, then Unicode character properties exist to help you with handling modern character data.

There are three cases in Unicode, not two. Furthermore, you also have noncased letters. Letters in general are specified by the \pL property, and each of these also belongs to exactly one of five subcategories:

  1. uppercase letters, specified with \p{Lu}; eg: AÇ?ÞSSS??ST
  2. titlecase letters, specified with \p{Lt}; eg: ??Ss?St (actually Ss and St are an upper- and then a lowercase letter, but they are what you get if you ask for the titlecase of ß and ?, respectively)
  3. lowercase letters, specified with \p{Ll}; eg: aaç??sþß??
  4. modifier letters, specified with \p{Lm}; eg: ????"'???
  5. other letters, specified with \p{Lo}; eg: ?????

You can take the complement of any of these, but do be careful, because something like \P{Lu} does not mean a letter that isn’t uppercase! It means any character that isn’t an uppercase letter.

For a letter that’s either of uppercase or titlecase, use [\p{Lu}\p{Lt}]. So you could use for your pattern:


If you don’t mean to limit the letters following the first to the “casing” letters alone, then you might prefer:


If you’re trying to match so-called “CamelCase” identifiers, then the actual rules depend on the programming language, but usually include the underscore character and the decimal numbers (\p{Nd}), and may also include a literal dollar sign and other language-dependent characters. If so, you may wish to add some of these to one or the other of the two character classes provided above.

For example, you may wish to add underscore to both but digits only to the second, leaving you with:


If, though, you are dealing with certain “words” from various RFCs and ISO standards, these are often specified as containing ASCII only. If so, you can get by with the literal [A-Z] idea. It’s just not kind to impose that restriction if it doesn’t actually exist.

How do I wrap text in a pre tag?

Use white-space: pre-wrap and some prefixes for automatic line breaking inside pres.

Do not use word-wrap: break-word because this just, of course, breaks a word in half which is probably something you do not want.

How to get featured image of a product in woocommerce

This should do the trick:

    $product_meta = get_post_meta($post_id);
    echo wp_get_attachment_image( $product_meta['_thumbnail_id'][0], 'full' );

You can change the parameters according to your needs.

Android Layout Weight

android:Layout_weight can be used when you don't attach a fix value to your width already like fill_parent etc.

Do something like this :



-----other parameters

How to select all records from one table that do not exist in another table?

Watch out for pitfalls. If the field Name in Table1 contain Nulls you are in for surprises. Better is:

FROM table2
    (SELECT ISNULL(name ,'')
     FROM table1)

How to convert BigDecimal to Double in Java?

Use doubleValue method present in BigDecimal class :

double doubleValue()

Converts this BigDecimal to a double.

No resource found that matches the given name: attr 'android:keyboardNavigationCluster'. when updating to Support Library 26.0.0

I was able to resolve it by updating sdk version and tools in gradle compileSdkVersion 26 buildToolsVersion "26.0.1"

and support library 26.0.1

Delaying AngularJS route change until model loaded to prevent flicker

I see some people asking how to do this using the angular.controller method with minification friendly dependency injection. Since I just got this working I felt obliged to come back and help. Here's my solution (adopted from the original question and Misko's answer):

angular.module('phonecat', ['phonecatFilters', 'phonecatServices', 'phonecatDirectives']).
  config(['$routeProvider', function($routeProvider) {
      when('/phones', {
        templateUrl: 'partials/phone-list.html', 
        controller: PhoneListCtrl, 
        resolve: { 
            phones: ["Phone", "$q", function(Phone, $q) {
                var deferred = $q.defer();
                Phone.query(function(successData) {
                }, function(errorData) {
                  deferred.reject(); // you could optionally pass error data here
                return deferred.promise;
            delay: ["$q","$defer", function($q, $defer) {
               var delay = $q.defer();
               $defer(delay.resolve, 1000);
               return delay.promise;

      when('/phones/:phoneId', {
        templateUrl: 'partials/phone-detail.html', 
        controller: PhoneDetailCtrl, 
        resolve: PhoneDetailCtrl.resolve}).
      otherwise({redirectTo: '/phones'});

angular.controller("PhoneListCtrl", [ "$scope", "phones", ($scope, phones) {
  $scope.phones = phones;
  $scope.orderProp = 'age';

Since this code is derived from the question/most popular answer it is untested, but it should send you in the right direction if you already understand how to make minification friendly angular code. The one part that my own code didn't requires was an injection of "Phone" into the resolve function for 'phones', nor did I use any 'delay' object at all.

I also recommend this youtube video , which helped me quite a bit

Should it interest you I've decided to also paste my own code (Written in coffeescript) so you can see how I got it working.

FYI, in advance I use a generic controller that helps me do CRUD on several models:

appModule.config ['$routeProvider', ($routeProvider) ->
  genericControllers = ["boards","teachers","classrooms","students"]
  for controllerName in genericControllers
      .when "/#{controllerName}/",
        action: 'confirmLogin'
        controller: 'GenericController'
        controllerName: controllerName
        templateUrl: "/static/templates/#{controllerName}.html"
          items : ["$q", "$route", "$http", ($q, $route, $http) ->
             deferred = $q.defer()
             controllerName = $route.current.controllerName
               method: "GET"
               url: "/api/#{controllerName}/"
             .success (response) ->
             .error (response) ->

             return deferred.promise

      redirectTo: '/'
      action: 'checkStatus'

appModule.controller "GenericController", ["$scope", "$route", "$http", "$cookies", "items", ($scope, $route, $http, $cookies, items) ->

  $scope.items = items
      #etc ....

.ssh directory not being created

Is there a step missing?

Yes. You need to create the directory:

mkdir ${HOME}/.ssh

Additionally, SSH requires you to set the permissions so that only you (the owner) can access anything in ~/.ssh:

% chmod 700 ~/.ssh

Should the .ssh dir be generated when I use the ssh-keygen command?

No. This command generates an SSH key pair but will fail if it cannot write to the required directory:

% ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/xxx/.ssh/id_rsa): /Users/tmp/does_not_exist
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
open /Users/tmp/does_not_exist failed: No such file or directory.
Saving the key failed: /Users/tmp/does_not_exist.

Once you've created your keys, you should also restrict who can read those key files to just yourself:

% chmod -R go-wrx ~/.ssh/*

Optional query string parameters in ASP.NET Web API

It's possible to pass multiple parameters as a single model as vijay suggested. This works for GET when you use the FromUri parameter attribute. This tells WebAPI to fill the model from the query parameters.

The result is a cleaner controller action with just a single parameter. For more information see:

public class BooksController : ApiController
    // GET /api/books?author=tolk&title=lord&isbn=91&somethingelse=ABC&date=1970-01-01
    public string GetFindBooks([FromUri]BookQuery query)
      // ...

  public class BookQuery
    public string Author { get; set; }
    public string Title { get; set; }
    public string ISBN { get; set; }
    public string SomethingElse { get; set; }
    public DateTime? Date { get; set; }

It even supports multiple parameters, as long as the properties don't conflict.

// GET /api/books?author=tolk&title=lord&isbn=91&somethingelse=ABC&date=1970-01-01
public string GetFindBooks([FromUri]BookQuery query, [FromUri]Paging paging)
  // ...

public class Paging
  public string Sort { get; set; }
  public int Skip { get; set; }
  public int Take { get; set; }

In order to ensure the values are optional make sure to use reference types or nullables (ex. int?) for the models properties.

ruby LoadError: cannot load such file

For security & other reasons, ruby does not by default include the current directory in the load_path. You may want to check this for more details - Why does Ruby 1.9.2 remove "." from LOAD_PATH, and what's the alternative?

How to backup MySQL database in PHP?

Based on the good solution that provided by tazo todua, I've made some of changes since mysql_connect has deprecated and not supported in new php version. I've used mysqli_connect instead and increased the performance of inserting values to the database:


* Updated: Mohammad M. AlBanna
* Website:

//MySQL server and database
$dbhost = 'localhost';
$dbuser = 'my_user';
$dbpass = 'my_pwd';
$dbname = 'database_name';
$tables = '*';

//Call the core function
backup_tables($dbhost, $dbuser, $dbpass, $dbname, $tables);

//Core function
function backup_tables($host, $user, $pass, $dbname, $tables = '*') {
    $link = mysqli_connect($host,$user,$pass, $dbname);

    // Check connection
    if (mysqli_connect_errno())
        echo "Failed to connect to MySQL: " . mysqli_connect_error();

    mysqli_query($link, "SET NAMES 'utf8'");

    //get all of the tables
    if($tables == '*')
        $tables = array();
        $result = mysqli_query($link, 'SHOW TABLES');
        while($row = mysqli_fetch_row($result))
            $tables[] = $row[0];
        $tables = is_array($tables) ? $tables : explode(',',$tables);

    $return = '';
    //cycle through
    foreach($tables as $table)
        $result = mysqli_query($link, 'SELECT * FROM '.$table);
        $num_fields = mysqli_num_fields($result);
        $num_rows = mysqli_num_rows($result);

        $return.= 'DROP TABLE IF EXISTS '.$table.';';
        $row2 = mysqli_fetch_row(mysqli_query($link, 'SHOW CREATE TABLE '.$table));
        $return.= "\n\n".$row2[1].";\n\n";
        $counter = 1;

        //Over tables
        for ($i = 0; $i < $num_fields; $i++) 
        {   //Over rows
            while($row = mysqli_fetch_row($result))
                if($counter == 1){
                    $return.= 'INSERT INTO '.$table.' VALUES(';
                } else{
                    $return.= '(';

                //Over fields
                for($j=0; $j<$num_fields; $j++) 
                    $row[$j] = addslashes($row[$j]);
                    $row[$j] = str_replace("\n","\\n",$row[$j]);
                    if (isset($row[$j])) { $return.= '"'.$row[$j].'"' ; } else { $return.= '""'; }
                    if ($j<($num_fields-1)) { $return.= ','; }

                if($num_rows == $counter){
                    $return.= ");\n";
                } else{
                    $return.= "),\n";

    //save file
    $fileName = 'db-backup-'.time().'-'.(md5(implode(',',$tables))).'.sql';
    $handle = fopen($fileName,'w+');
        echo "Done, the file name is: ".$fileName;

could not extract ResultSet in hibernate

Another solution is add @JsonIgnore :

@OneToMany(mappedBy="catalog", fetch = FetchType.LAZY)
private Set<Product> products = new HashSet<Product>(0);

Select elements by attribute in CSS

    [data-value] {
  /* Attribute exists */

[data-value="foo"] {
  /* Attribute has this exact value */

[data-value*="foo"] {
  /* Attribute value contains this value somewhere in it */

[data-value~="foo"] {
  /* Attribute has this value in a space-separated list somewhere */

[data-value^="foo"] {
  /* Attribute value starts with this */

[data-value|="foo"] {
  /* Attribute value starts with this in a dash-separated list */

[data-value$="foo"] {
  /* Attribute value ends with this */

There is an error in XML document (1, 41)

In my case I had a float value expected where xml had a null value so be sure to search for float and int data type in your xsd map

How to revert a "git rm -r ."?

If you end up with none of the above working, you might be able to retrieve data using the suggestion from here:

git prune -n
git cat-file -p <blob #>

How to resolve "Server Error in '/' Application" error?

vs2017 just added in these lines to csproj.user file


with these lines in Web.config

<compilation debug="true" targetFramework="4.5" />
<httpRuntime targetFramework="4.5" maxRequestLength="1048576" />
<identity impersonate="false" />
<authentication mode="Windows" />
  <allow users="yourNTusername" />
  <deny users="?" />

And it worked

jQuery select child element by class with unknown path

Try this

$('#thisElement .classToSelect').each(function(i){
         // do stuff

Hope it will help

How to build splash screen in windows forms application?

First you should create a form with or without Border (border-less is preferred for these things)

public class SplashForm : Form
    Form _Parent;
    BackgroundWorker worker;
    public SplashForm(Form parent)
         BackgroundWorker worker = new BackgroundWorker();
         this.worker.DoWork += new System.ComponentModel.DoWorkEventHandler(this.worker _DoWork);
         _Parent = parent;
    private void worker _DoWork(object sender, DoWorkEventArgs e)

At Main you should use that

   static class Program
            static void Main()
                Application.Run(new SplashForm());

The remote certificate is invalid according to the validation procedure

.NET is seeing an invalid SSL certificate on the other end of the connection. There is a workaround for it, but obviously not recommended for production code:

// Put this somewhere that is only once - like an initialization method
ServicePointManager.ServerCertificateValidationCallback += new RemoteCertificateValidationCallback(ValidateCertificate);

static bool ValidateCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
   return true;

How to share data between different threads In C# using AOP?

Look at the following example code:

public class MyWorker
    public SharedData state;
    public void DoWork(SharedData someData)
        this.state = someData;
        while (true) ;


public class SharedData {
    X myX;
    public getX() { etc
    public setX(anX) { etc


public class Program
    public static void Main()
        SharedData data = new SharedDate()
        MyWorker work1 = new MyWorker(data);
        MyWorker work2 = new MyWorker(data);
        Thread thread = new Thread(new ThreadStart(work1.DoWork));
        Thread thread2 = new Thread(new ThreadStart(work2.DoWork));

In this case, the thread class MyWorker has a variable state. We initialise it with the same object. Now you can see that the two workers access the same SharedData object. Changes made by one worker are visible to the other.

You have quite a few remaining issues. How does worker 2 know when changes have been made by worker 1 and vice-versa? How do you prevent conflicting changes? Maybe read: this tutorial.

scrollTop animation without jquery


<button onclick="scrollToTop(1000);"></button>

1# JavaScript (linear):

function scrollToTop (duration) {
    // cancel if already on top
    if (document.scrollingElement.scrollTop === 0) return;

    const totalScrollDistance = document.scrollingElement.scrollTop;
    let scrollY = totalScrollDistance, oldTimestamp = null;

    function step (newTimestamp) {
        if (oldTimestamp !== null) {
            // if duration is 0 scrollY will be -Infinity
            scrollY -= totalScrollDistance * (newTimestamp - oldTimestamp) / duration;
            if (scrollY <= 0) return document.scrollingElement.scrollTop = 0;
            document.scrollingElement.scrollTop = scrollY;
        oldTimestamp = newTimestamp;

2# JavaScript (ease in and out):

function scrollToTop (duration) {
    // cancel if already on top
    if (document.scrollingElement.scrollTop === 0) return;

    const cosParameter = document.scrollingElement.scrollTop / 2;
    let scrollCount = 0, oldTimestamp = null;

    function step (newTimestamp) {
        if (oldTimestamp !== null) {
            // if duration is 0 scrollCount will be Infinity
            scrollCount += Math.PI * (newTimestamp - oldTimestamp) / duration;
            if (scrollCount >= Math.PI) return document.scrollingElement.scrollTop = 0;
            document.scrollingElement.scrollTop = cosParameter + cosParameter * Math.cos(scrollCount);
        oldTimestamp = newTimestamp;
  - pi is the length/end point of the cosinus intervall (see below)
  - newTimestamp indicates the current time when callbacks queued by requestAnimationFrame begin to fire.
    (for more information see
  - newTimestamp - oldTimestamp equals the delta time

    a * cos (bx + c) + d                        | c translates along the x axis = 0
  = a * cos (bx) + d                            | d translates along the y axis = 1 -> only positive y values
  = a * cos (bx) + 1                            | a stretches along the y axis = cosParameter = window.scrollY / 2
  = cosParameter + cosParameter * (cos bx)  | b stretches along the x axis = scrollCount = Math.PI / (scrollDuration / (newTimestamp - oldTimestamp))
  = cosParameter + cosParameter * (cos scrollCount * x)


  • Duration in milliseconds (1000ms = 1s)
  • Second script uses the cos function. Example curve:

enter image description here

3# Simple scrolling library on Github

Turning multiple lines into one comma separated line

sed -n 's/.*/&,/;H;$x;$s/,\n/,/g;$s/\n\(.*\)/\1/;$s/\(.*\),/\1/;$p'

Calling pylab.savefig without display in ipython

We don't need to plt.ioff() or (if we use %matplotlib inline). You can test above code without plt.ioff(). plt.close() has the essential role. Try this one:

%matplotlib inline
import pylab as plt

# It doesn't matter you add line below. You can even replace it by 'plt.ion()', but you will see no changes.
## plt.ioff()

# Create a new figure, plot into it, then close it so it never gets displayed
fig = plt.figure()

# Create a new figure, plot into it, then don't close it so it does get displayed
fig2 = plt.figure()

If you run this code in iPython, it will display a second plot, and if you add plt.close(fig2) to the end of it, you will see nothing.

In conclusion, if you close figure by plt.close(fig), it won't be displayed.

How to set the action for a UIBarButtonItem in Swift

Swift 5 & iOS 13+ Programmatic Example

  1. You must mark your function with @objc, see below example!
  2. No parenthesis following after the function name! Just use #selector(name).
  3. private or public doesn't matter; you can use private.

Code Example

override func viewWillAppear(_ animated: Bool) {
    let menuButtonImage = UIImage(systemName: "flame")
    let menuButton = UIBarButtonItem(image: menuButtonImage, style: .plain, target: self, action: #selector(didTapMenuButton))
    navigationItem.rightBarButtonItem = menuButton

@objc public func didTapMenuButton() {
    print("Hello World")

OpenCV Python rotate image by X degrees around specific point

You can simply use the imutils package to do the rotation. it has two methods

  1. rotate: Rotate the image at specified angle. however the drawback is image might get cropped if it is not a square image.
  2. Rotate_bound: it overcomes the problem happened with rotate. It adjusts the size of the image accordingly while rotating the image.

more info you can get on this blog:

How to customize listview using baseadapter

public class ListElementAdapter extends BaseAdapter{

    String[] data;
    Context context;
    LayoutInflater layoutInflater;

    public ListElementAdapter(String[] data, Context context) {
        super(); = data;
        this.context = context;
        layoutInflater = LayoutInflater.from(context);

    public int getCount() {

        return data.length;

    public Object getItem(int position) {

        return null;

    public long getItemId(int position) {

        return position;

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

        convertView= layoutInflater.inflate(R.layout.item, null);

        TextView txt=(TextView)convertView.findViewById(;


        return convertView;

Just call ListElementAdapter in your Main Activity and set Adapter to ListView.

HTML embed autoplay="false", but still plays automatically

Chrome doesn't seem to understand true and false. Use autostart="1" and autostart="0" instead.

Source: (Google Groups:!topic/chrome/LkA8FoBoleU)

How do I convert ticks to minutes?

You can do this way :

TimeSpan duration = new TimeSpan(tickCount)
double minutes = duration.TotalMinutes;

how concatenate two variables in batch script?

You can do it without setlocal, because of the setlocal command the variable won't survive an endlocal because it was created in setlocal. In this way the variable will be defined the right way.

To do that use this code:

set var1=A

set var2=B

set AB=hi

call set newvar=%%%var1%%var2%%%

echo %newvar% 

Note: You MUST use call before you set the variable or it won't work.

What generates the "text file busy" message in Unix?

This error means some other process or user is accessing your file. Use lsof to check what other processes are using it. You can use kill command to kill it if needed.

How do you create vectors with specific intervals in R?

Usually, we want to divide our vector into a number of intervals. In this case, you can use a function where (a) is a vector and (b) is the number of intervals. (Let's suppose you want 4 intervals)

a <- 1:10
b <- 4

FunctionIntervalM <- function(a,b) {
  seq(from=min(a), to = max(a), by = (max(a)-min(a))/b)

# 1.00  3.25  5.50  7.75 10.00

Therefore you have 4 intervals:

1.00 - 3.25 
3.25 - 5.50
5.50 - 7.75
7.75 - 10.00

You can also use a cut function

  cut(a, 4)

# (0.991,3.25] (0.991,3.25] (0.991,3.25] (3.25,5.5]   (3.25,5.5]   (5.5,7.75]  
# (5.5,7.75]   (7.75,10]    (7.75,10]    (7.75,10]   
#Levels: (0.991,3.25] (3.25,5.5] (5.5,7.75] (7.75,10]

HTML Drag And Drop On Mobile Devices

jQuery UI Touch Punch just solves it all.

It's a Touch Event Support for jQuery UI. Basically, it just wires touch event back to jQuery UI. Tested on iPad, iPhone, Android and other touch-enabled mobile devices. I used jQuery UI sortable and it works like a charm.

Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/JDBC_DBO]]

Windows -> Preferences -> Server -> Runtime Environment -> Delete all Apache servers available. Add the same. Now run your application on server. Its done :)

Could not find a version that satisfies the requirement <package>

After 2 hours of searching, I found a way to fix it with just one line of command. You need to know the version of the package (Just search up PACKAGE version).


python3 -m pip install --pre --upgrade PACKAGE==VERSION.VERSION.VERSION

How to 'restart' an android application programmatically

Checkout intent properties like no history , clear back stack etc ... Intent.setFlags

Intent mStartActivity = new Intent(HomeActivity.this, SplashScreen.class);
int mPendingIntentId = 123456;
PendingIntent mPendingIntent = PendingIntent.getActivity(HomeActivity.this, mPendingIntentId, mStartActivity,
AlarmManager mgr = (AlarmManager) HomeActivity.this.getSystemService(Context.ALARM_SERVICE);
mgr.set(AlarmManager.RTC, System.currentTimeMillis() + 100, mPendingIntent);

How to find where gem files are installed

I found it useful to get a location of the library file with:

gem which *gemname*

Round up to Second Decimal Place in Python

Note that the ceil(num * 100) / 100 trick will crash on some degenerate inputs, like 1e308. This may not come up often but I can tell you it just cost me a couple of days. To avoid this, "it would be nice if" ceil() and floor() took a decimal places argument, like round() does... Meanwhile, anyone know a clean alternative that won't crash on inputs like this? I had some hopes for the decimal package but it seems to die too:

>>> from math import ceil
>>> from decimal import Decimal, ROUND_DOWN, ROUND_UP
>>> num = 0.1111111111000
>>> ceil(num * 100) / 100
>>> float(Decimal(num).quantize(Decimal('.01'), rounding=ROUND_UP))
>>> num = 1e308
>>> ceil(num * 100) / 100
Traceback (most recent call last):
  File "<string>", line 301, in runcode
  File "<interactive input>", line 1, in <module>
OverflowError: cannot convert float infinity to integer
>>> float(Decimal(num).quantize(Decimal('.01'), rounding=ROUND_UP))
Traceback (most recent call last):
  File "<string>", line 301, in runcode
  File "<interactive input>", line 1, in <module>
decimal.InvalidOperation: [<class 'decimal.InvalidOperation'>]

Of course one might say that crashing is the only sane behavior on such inputs, but I would argue that it's not the rounding but the multiplication that's causing the problem (that's why, eg, 1e306 doesn't crash), and a cleaner implementation of the round-up-nth-place fn would avoid the multiplication hack.

document.getElementById().value doesn't set the value

The only case I could imagine is, that you run this on a webkit browser like Chrome or Safari and your return value in responseText, contains a string value.

In that constelation, the value cannot be displayed (it would get blank)


My point here is, that I expect a wrong/double encoded string value. Webkit browsers are more strict on the type = number. If there is "only" a white-space issue, you can try to implicitly call the Number() constructor, like

document.getElementById("points").value = +request.responseText;

Can't build create-react-app project with custom PUBLIC_URL

People like me who are looking for something like this in in build:

<script type="text/javascript" src="">

Then setting to homepage in package.json will not work.

1. Quick Solution

Build your project like this:

set PUBLIC_URL= run build


PUBLIC_URL= npm run build

And you will get

<script type="text/javascript" src="">

in your built index.html

2. Permanent & Recommended Solution

Create a file called .env at your project root(same place where package.json is located).
In this file write this(no quotes around the url):


Build your project as usual (npm run build)
This will also generate index.html with:

<script type="text/javascript" src="">

3. Weird Solution (Will do not work in latest react-scripts version)

Add this in your package.json
"homepage": "http://://",

Then index.html will be generated with:

<script type="text/javascript" src="//">

Which is basically the same as:

<script type="text/javascript" src="">

in my understanding.

Github Issue Github Comment

Proper usage of Optional.ifPresent()

Optional<User>.ifPresent() takes a Consumer<? super User> as argument. You're passing it an expression whose type is void. So that doesn't compile.

A Consumer is intended to be implemented as a lambda expression:

Optional<User> user = ...
user.ifPresent(theUser -> doSomethingWithUser(theUser));

Or even simpler, using a method reference:

Optional<User> user = ...

This is basically the same thing as

Optional<User> user = ...
user.ifPresent(new Consumer<User>() {
    public void accept(User theUser) {

The idea is that the doSomethingWithUser() method call will only be executed if the user is present. Your code executes the method call directly, and tries to pass its void result to ifPresent().

How can we run a test method with multiple parameters in MSTest?

I couldn't get The DataRowAttribute to work in Visual Studio 2015, and this is what I ended up with:

public class Tests
    private Foo _toTest;

    public void Setup()
        this._toTest = new Foo();

    public void ATest()
        this.Perform_ATest(1, 1, 2);

        this.Perform_ATest(100, 200, 300);

        this.Perform_ATest(817001, 212, 817213);

    private void Perform_ATest(int a, int b, int expected)
        // Obviously this would be way more complex...

        Assert.IsTrue(this._toTest.Add(a,b) == expected);

public class Foo
    public int Add(int a, int b)
        return a + b;

The real solution here is to just use NUnit (unless you're stuck in MSTest like I am in this particular instance).

@synthesize vs @dynamic, what are the differences?

As per the documentation:

@dynamic tells the compiler that the accessor methods are provided at runtime.

With a little bit of investigation I found out that providing accessor methods override the @dynamic directive.

@synthesize tells the compiler to create those accessors for you (getter and setter)

@property tells the compiler that the accessors will be created, and that can be accessed with the dot notation or [object message]

Using Gulp to Concatenate and Uglify files

var gulp = require('gulp');
var concat = require('gulp-concat');
var uglify = require('gulp-uglify');

gulp.task('create-vendor', function () {
var files = [

return gulp.src(files)

Your solution does not work because you need to save file after concat process and then uglify and save again. You do not need to rename file between concat and uglify.

Log record changes in SQL server in an audit table

Take a look at this article on by Pop Rivett. It walks you through creating a generic trigger that will log the OLDVALUE and the NEWVALUE for all updated columns. The code is very generic and you can apply it to any table you want to audit, also for any CRUD operation i.e. INSERT, UPDATE and DELETE. The only requirement is that your table to be audited should have a PRIMARY KEY (which most well designed tables should have anyway).

Here's the code relevant for your GUESTS Table.

  1. Create AUDIT Table.
          (SELECT * FROM sysobjects WHERE id = OBJECT_ID(N'[dbo].[Audit]') 
                   AND OBJECTPROPERTY(id, N'IsUserTable') = 1)
           CREATE TABLE Audit 
                   (Type CHAR(1), 
                   TableName VARCHAR(128), 
                   PK VARCHAR(1000), 
                   FieldName VARCHAR(128), 
                   OldValue VARCHAR(1000), 
                   NewValue VARCHAR(1000), 
                   UpdateDate datetime, 
                   UserName VARCHAR(128))
  1. CREATE an UPDATE Trigger on the GUESTS Table as follows.
    DECLARE @bit INT ,
           @field INT ,
           @maxfield INT ,
           @char INT ,
           @fieldname VARCHAR(128) ,
           @TableName VARCHAR(128) ,
           @PKCols VARCHAR(1000) ,
           @sql VARCHAR(2000), 
           @UpdateDate VARCHAR(21) ,
           @UserName VARCHAR(128) ,
           @Type CHAR(1) ,
           @PKSelect VARCHAR(1000)
    --You will need to change @TableName to match the table to be audited. 
    -- Here we made GUESTS for your example.
    SELECT @TableName = 'GUESTS'
    -- date and user
    SELECT         @UserName = SYSTEM_USER ,
           @UpdateDate = CONVERT (NVARCHAR(30),GETDATE(),126)
    -- Action
    IF EXISTS (SELECT * FROM inserted)
           IF EXISTS (SELECT * FROM deleted)
                   SELECT @Type = 'U'
                   SELECT @Type = 'I'
           SELECT @Type = 'D'
    -- get list of columns
    SELECT * INTO #ins FROM inserted
    SELECT * INTO #del FROM deleted
    -- Get primary key columns for full outer join
    SELECT @PKCols = COALESCE(@PKCols + ' and', ' on') 
                   + ' i.' + c.COLUMN_NAME + ' = d.' + c.COLUMN_NAME
           WHERE   pk.TABLE_NAME = @TableName
           AND     c.TABLE_NAME = pk.TABLE_NAME
    -- Get primary key select for insert
    SELECT @PKSelect = COALESCE(@PKSelect+'+','') 
           + '''<' + COLUMN_NAME 
           + '=''+convert(varchar(100),
    coalesce(i.' + COLUMN_NAME +',d.' + COLUMN_NAME + '))+''>''' 
           WHERE   pk.TABLE_NAME = @TableName
           AND     c.TABLE_NAME = pk.TABLE_NAME
    IF @PKCols IS NULL
           RAISERROR('no PK on table %s', 16, -1, @TableName)
    SELECT         @field = 0, 
           @maxfield = MAX(ORDINAL_POSITION) 
    WHILE @field < @maxfield
           SELECT @field = MIN(ORDINAL_POSITION) 
                   WHERE TABLE_NAME = @TableName 
                   AND ORDINAL_POSITION > @field
           SELECT @bit = (@field - 1 )% 8 + 1
           SELECT @bit = POWER(2,@bit - 1)
           SELECT @char = ((@field - 1) / 8) + 1
           IF SUBSTRING(COLUMNS_UPDATED(),@char, 1) & @bit > 0
                                           OR @Type IN ('I','D')
                   SELECT @fieldname = COLUMN_NAME 
                           FROM INFORMATION_SCHEMA.COLUMNS 
                           WHERE TABLE_NAME = @TableName 
                           AND ORDINAL_POSITION = @field
                   SELECT @sql = '
    insert Audit (    Type, 
    select ''' + @Type + ''',''' 
           + @TableName + ''',' + @PKSelect
           + ',''' + @fieldname + ''''
           + ',convert(varchar(1000),d.' + @fieldname + ')'
           + ',convert(varchar(1000),i.' + @fieldname + ')'
           + ',''' + @UpdateDate + ''''
           + ',''' + @UserName + ''''
           + ' from #ins i full outer join #del d'
           + @PKCols
           + ' where i.' + @fieldname + ' <> d.' + @fieldname 
           + ' or (i.' + @fieldname + ' is null and  d.'
                                    + @fieldname
                                    + ' is not null)' 
           + ' or (i.' + @fieldname + ' is not null and  d.' 
                                    + @fieldname
                                    + ' is null)' 
                   EXEC (@sql)