Programs & Examples On #Text recognition

How to index an element of a list object in R

Indexing a list is done using double bracket, i.e. hypo_list[[1]] (e.g. have a look here: BTW: read.table does not return a table but a dataframe (see value section in ?read.table). So you will have a list of dataframes, rather than a list of table objects. The principal mechanism is identical for tables and dataframes though.

Note: In R, the index for the first entry is a 1 (not 0 like in some other languages).


l <- list(anscombe, iris)   # put dfs in list
l[[1]]             # returns anscombe dataframe

anscombe[1:2, 2]   # access first two rows and second column of dataset
[1] 10  8

l[[1]][1:2, 2]     # the same but selecting the dataframe from the list first
[1] 10  8

Table objects

tbl1 <- table(sample(1:5, 50, rep=T))
tbl2 <- table(sample(1:5, 50, rep=T))
l <- list(tbl1, tbl2)  # put tables in a list

tbl1[1:2]              # access first two elements of table 1 

Now with the list

l[[1]]                 # access first table from the list

1  2  3  4  5 
9 11 12  9  9 

l[[1]][1:2]            # access first two elements in first table

1  2 
9 11 

How do I see active SQL Server connections?

I threw this together so that you could do some querying on the results

Declare @dbName varchar(150)
set @dbName = '[YOURDATABASENAME]'

--Total machine connections
--SELECT  COUNT(dbid) as TotalConnections FROM sys.sysprocesses WHERE dbid > 0

--Available connections
DECLARE @SPWHO1 TABLE (DBName VARCHAR(1000) NULL, NoOfAvailableConnections VARCHAR(1000) NULL, LoginName VARCHAR(1000) NULL)
    SELECT db_name(dbid), count(dbid), loginame FROM sys.sysprocesses WHERE dbid > 0 GROUP BY dbid, loginame

--Running connections
DECLARE @SPWHO2 TABLE (SPID VARCHAR(1000), [Status] VARCHAR(1000) NULL, [Login] VARCHAR(1000) NULL, HostName VARCHAR(1000) NULL, BlkBy VARCHAR(1000) NULL, DBName VARCHAR(1000) NULL, Command VARCHAR(1000) NULL, CPUTime VARCHAR(1000) NULL, DiskIO VARCHAR(1000) NULL, LastBatch VARCHAR(1000) NULL, ProgramName VARCHAR(1000) NULL, SPID2 VARCHAR(1000) NULL, Request VARCHAR(1000) NULL)
    EXEC sp_who2 'Active'

Export specific rows from a PostgreSQL table as INSERT SQL script

have u tried in pgadmin executing query with " EXECUTE QUERY WRITE RESULT TO FILE " option

its only export the data, else try like

pg_dump -t view_name DB_name > db.sql

-t option used for ==> Dump only tables (or views or sequences) matching table, refer

How to update multiple columns in single update statement in DB2

I know it's an old question, but I just had to find solution for multiple rows update where multiple records had to updated with different values based on their IDs and I found that I can use a a scalar-subselect:

  WHERE RESPEMP='000030'

(with WHERE optional, of course)

Also, I found that it is critical to specify that no NULL values would not be used in this update (in case not all records in first table have corresponding record in the second one), this way:



How to retrieve inserted id after inserting row in SQLite using Python?

You could use cursor.lastrowid (see "Optional DB API Extensions"):

cursor.execute('''CREATE TABLE foo (id integer primary key autoincrement ,
                                    username varchar(50),
                                    password varchar(50))''')
cursor.execute('INSERT INTO foo (username,password) VALUES (?,?)',
# 1

If two people are inserting at the same time, as long as they are using different cursors, cursor.lastrowid will return the id for the last row that cursor inserted:

cursor.execute('INSERT INTO foo (username,password) VALUES (?,?)',

cursor2.execute('INSERT INTO foo (username,password) VALUES (?,?)',

# 3
# 2

cursor.execute('INSERT INTO foo (id,username,password) VALUES (?,?,?)',
# 100

Note that lastrowid returns None when you insert more than one row at a time with executemany:

cursor.executemany('INSERT INTO foo (username,password) VALUES (?,?)',
# None

How to avoid the "Windows Defender SmartScreen prevented an unrecognized app from starting warning"

After clicking on Properties of any installer(.exe) which block your application to install (Windows Defender SmartScreen prevented an unrecognized app ) for that issue i found one solution

  1. Right click on installer(.exe)
  2. Select properties option.
  3. Click on checkbox to check Unblock at the bottom of Properties.

This solution work for Heroku CLI (heroku-x64) installer(.exe)

How to uncheck a radio button?

You wouldn't need the each function

$("input:radio").attr("checked", false);



The same should also apply to your textbox:

$('#frm input[type="text"]').val("");

But you could improve this

$('#frm input:text').val("");

The transaction manager has disabled its support for remote/network transactions

I had a store procedure that call another store Procedure in "linked server".when I execute it in ssms it was ok,but when I call it in application(By Entity Framework),I got this error. This article helped me and I used this script:

EXEC sp_serveroption @server = 'LinkedServer IP or Name',@optname = 'remote proc transaction promotion', @optvalue = 'false' ;

for more detail look at this: Linked server : The partner transaction manager has disabled its support for remote/network transactions

Could not load file or assembly CrystalDecisions.ReportAppServer.ClientDoc

Regarding the 64-bit system wanting 32-bit support. I don't find it so bizarre:

Although deployed to a 64-bit system, this doesn't mean all the referenced assemblies are necessarily 64-bit Crystal Reports assemblies. Further to that, the Crystal Reports assemblies are largely just wrappers to a collection of legacy DLLs upon which they are based. Many 32-bit DLLs are required by the primarily referenced assembly. The error message "can not load the assembly" involves these DLLs as well. To see visually what those are, go to and run 'Depends' on the assembly in question, directly on that IIS server.

Reading a text file and splitting it into single words in python

Given this file:

$ cat words.txt
line1 word1 word2
line2 word3 word4
line3 word5 word6

If you just want one word at a time (ignoring the meaning of spaces vs line breaks in the file):

with open('words.txt','r') as f:
    for line in f:
        for word in line.split():



Similarly, if you want to flatten the file into a single flat list of words in the file, you might do something like this:

with open('words.txt') as f:
    flat_list=[word for line in f for word in line.split()]

>>> flat_list
['line1', 'word1', 'word2', 'line2', 'word3', 'word4', 'line3', 'word5', 'word6']

Which can create the same output as the first example with print '\n'.join(flat_list)...

Or, if you want a nested list of the words in each line of the file (for example, to create a matrix of rows and columns from a file):

with open('words.txt') as f:
    matrix=[line.split() for line in f]

>>> matrix
[['line1', 'word1', 'word2'], ['line2', 'word3', 'word4'], ['line3', 'word5', 'word6']]

If you want a regex solution, which would allow you to filter wordN vs lineN type words in the example file:

import re
with open("words.txt") as f:
    for line in f:
        for word in re.findall(r'\bword\d+', line):
            # wordN by wordN with no lineN

Or, if you want that to be a line by line generator with a regex:

 with open("words.txt") as f:
     (word for line in f for word in re.findall(r'\w+', line))

How do I bind a List<CustomObject> to a WPF DataGrid?

You dont need to give column names manually in xaml. Just set AutoGenerateColumns property to true and your list will be automatically binded to DataGrid. refer code. XAML Code:

    <DataGrid x:Name="MyDatagrid" AutoGenerateColumns="True" Height="447" HorizontalAlignment="Left" Margin="20,85,0,0" VerticalAlignment="Top" Width="799"  ItemsSource="{Binding Path=ListTest, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"  CanUserAddRows="False"> </Grid>


Public Class Test 
    public string m_field1_Test{get;set;}
    public string m_field2_Test { get; set; }
    public Test()
        m_field1_Test = "field1";
        m_field2_Test = "field2";
    public MainWindow()

        listTest = new List<Test>();

        for (int i = 0; i < 10; i++)
            obj = new Test();


        this.MyDatagrid.ItemsSource = ListTest;



How to write hello world in assembler under Windows?

These are Win32 and Win64 examples using Windows API calls. They are for MASM rather than NASM, but have a look at them. You can find more details in this article.

This uses MessageBox instead of printing to stdout.

Win32 MASM

;---ASM Hello World Win32 MessageBox

.model flat, stdcall
includelib kernel32.lib
includelib user32.lib

title db 'Win32', 0
msg db 'Hello World', 0


push 0            ; uType = MB_OK
push offset title ; LPCSTR lpCaption
push offset msg   ; LPCSTR lpText
push 0            ; hWnd = HWND_DESKTOP
call MessageBoxA
push eax          ; uExitCode = MessageBox(...)
call ExitProcess

End Main

Win64 MASM

;---ASM Hello World Win64 MessageBox

extrn MessageBoxA: PROC
extrn ExitProcess: PROC

title db 'Win64', 0
msg db 'Hello World!', 0

main proc
  sub rsp, 28h  
  mov rcx, 0       ; hWnd = HWND_DESKTOP
  lea rdx, msg     ; LPCSTR lpText
  lea r8,  title   ; LPCSTR lpCaption
  mov r9d, 0       ; uType = MB_OK
  call MessageBoxA
  add rsp, 28h  
  mov ecx, eax     ; uExitCode = MessageBox(...)
  call ExitProcess
main endp


To assemble and link these using MASM, use this for 32-bit executable:

ml.exe [filename] /link /subsystem:windows 
/defaultlib:kernel32.lib /defaultlib:user32.lib /entry:Main

or this for 64-bit executable:

ml64.exe [filename] /link /subsystem:windows 
/defaultlib:kernel32.lib /defaultlib:user32.lib /entry:main

Why does x64 Windows need to reserve 28h bytes of stack space before a call? That's 32 bytes (0x20) of shadow space aka home space, as required by the calling convention. And another 8 bytes to re-align the stack by 16, because the calling convention requires RSP be 16-byte aligned before a call. (Our main's caller (in the CRT startup code) did that. The 8-byte return address means that RSP is 8 bytes away from a 16-byte boundary on entry to a function.)

Shadow space can be used by a function to dump its register args next to where any stack args (if any) would be. A system call requires 30h (48 bytes) to also reserve space for r10 and r11 in addition to the previously mentioned 4 registers. But DLL calls are just function calls, even if they're wrappers around syscall instructions.

Fun fact: non-Windows, i.e. the x86-64 System V calling convention (e.g. on Linux) doesn't use shadow space at all, and uses up to 6 integer/pointer register args, and up to 8 FP args in XMM registers.

Using MASM's invoke directive (which knows the calling convention), you can use one ifdef to make a version of this which can be built as 32-bit or 64-bit.

ifdef rax
    extrn MessageBoxA: PROC
    extrn ExitProcess: PROC
    .model flat, stdcall
    includelib kernel32.lib
    includelib user32.lib
caption db 'WinAPI', 0
text    db 'Hello World', 0
main proc
    invoke MessageBoxA, 0, offset text, offset caption, 0
    invoke ExitProcess, eax
main endp

The macro variant is the same for both, but you won't learn assembly this way. You'll learn C-style asm instead. invoke is for stdcall or fastcall while cinvoke is for cdecl or variable argument fastcall. The assembler knows which to use.

You can disassemble the output to see how invoke expanded.

Getting "Cannot call a class as a function" in my React Project

Mostly these issues occur when you miss extending Component from react:

import React, {Component} from 'react'

export default class TimePicker extends Component {
    render() {

Angular2 module has no exported member

This error can also occur if your interface name is different than the file it is contained in. Read about ES6 modules for details. If the SignInComponent was an interface, as was in my case, then


should be in a file named SignInComponent.ts.

Fix CSS hover on iPhone/iPad/iPod

Here is a very slight improvement to user1387483's answer using an immediate function:

(function() {
  $("*").on( 'touchstart', function() {
    $(this).trigger('hover') ;
  } ).on('touchend', function() {
    $(this).trigger('hover') ;
  } ) ;
})() ;

Also, I agree with Boz that this appears to be the "neatest, most compliant solution".

Java ArrayList for integers

How about creating an ArrayList of a set amount of Integers?

The below method returns an ArrayList of a set amount of Integers.

public static ArrayList<Integer> createRandomList(int sizeParameter)
    // An ArrayList that method returns
    ArrayList<Integer> setIntegerList = new ArrayList<Integer>(sizeParameter);
    // Random Object helper
    Random randomHelper = new Random();
    for (int x = 0; x < sizeParameter; x++)
    }   // End of the for loop
    return setIntegerList;

Charts for Android

SciChart for Android is a relative newcomer, but brings extremely fast high performance real-time charting to the Android platform.

SciChart is a commercial control but available under royalty free distribution / per developer licensing. There is also free licensing available for educational use with some conditions.

Some useful links can be found below:

enter image description here

Disclosure: I am the tech lead on the SciChart project!

Bootstrap - dropdown menu not working?

you are missing the "btn btn-navbar" section. For example:

        <a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>

Take a look to navbar documentation in:

Twitter Bootstrap

What does += mean in Python?

a += b

is in this case the same as

a = a + b

In this case cnt += 1 means that cnt is increased by one.

Note that the code you pasted will loop indefinitely if cnt > 0 and len(aStr) > 1.

Edit: quote Carl Meyer: ``[..] the answer is misleadingly mostly correct. There is a subtle but very significant difference between + and +=, see Bastien's answer.''.

Hexadecimal string to byte array in C

    In main()
printf("enter string :\n");
    fgets(buf, 200, stdin);
unsigned char str_len = strlen(buf);
unsigned char bytearray[100];
        { bytearray[k++]=converttohex(&buffer[j]);   
                printf(" %02X",bytearray[k-1]);


    Use this 

    int converttohex(char * val)
        unsigned char temp = toupper(*val);
        unsigned char fin=0;



        temp = toupper(*(val+1));



        fin=fin|(temp & 0x0f);

           return fin;

Java - Search for files in a directory

public class searchingFile 
     static String path;//defining(not initializing) these variables outside main 
     static String filename;//so that recursive function can access them
     static int counter=0;//adding static so that can be accessed by static methods 

    public static void main(String[] args) //main methods begins
        Scanner sc=new Scanner(;
        System.out.println("Enter the path : ");
        path=sc.nextLine(); //storing path in path variable
        System.out.println("Enter file name : ");
        filename=sc.nextLine(); //storing filename in filename variable
        searchfile(path);//calling our recursive function and passing path as argument
        System.out.println("Number of locations file found at : "+counter);//Printing occurences


    public static String searchfile(String path)//declaring recursive function having return 
                                                //type and argument both strings

        File file=new File(path);//denoting the path
        File[] filelist=file.listFiles();//storing all the files and directories in array

    for (int i = 0; i < filelist.length; i++) //for loop for accessing all resources
        if(filelist[i].getName().equals(filename))//if loop is true if resource name=filename
            System.out.println("File is present at : "+filelist[i].getAbsolutePath());
            //if loop is true,this will print it's location
            counter++;//counter increments if file found
        if(filelist[i].isDirectory())// if resource is a directory,we want to inside that folder
            path=filelist[i].getAbsolutePath();//this is the path of the subfolder
            searchfile(path);//this path is again passed into the searchfile function 
                             //and this countinues untill we reach a file which has
                             //no sub directories

    return path;// returning path variable as it is the return type and also 
                // because function needs path as argument.


NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equalsIgnoreCase(java.lang.String)' on a null object reference

called_from must be null. Add a test against that condition like

if (called_from != null && called_from.equalsIgnoreCase("add")) {

or you could use Yoda conditions (per the Advantages in the linked Wikipedia article it can also solve some types of unsafe null behavior they can be described as placing the constant portion of the expression on the left side of the conditional statement)

if ("add".equalsIgnoreCase(called_from)) { // <-- safe if called_from is null

"git rebase origin" vs."git rebase origin/master"

Here's a better option:

git remote set-head -a origin

From the documentation:

With -a, the remote is queried to determine its HEAD, then $GIT_DIR/remotes//HEAD is set to the same branch. e.g., if the remote HEAD is pointed at next, "git remote set-head origin -a" will set $GIT_DIR/refs/remotes/origin/HEAD to refs/remotes/origin/next. This will only work if refs/remotes/origin/next already exists; if not it must be fetched first.

This has actually been around quite a while (since v1.6.3); not sure how I missed it!

You must add a reference to assembly 'netstandard, Version=

Manually editing the .csproj file and adding the reference below worked for me.

<Reference Include="netstandard" />

Thank you to Fahad Alshaya who suggested it here.

Transpose a range in VBA

Something like this should do it for you.

Sub CombineColumns1()
    Dim xRng As Range
    Dim i As Long, j As Integer
    Dim xNextRow As Long
    Dim xTxt As String
    On Error Resume Next
    With ActiveSheet
        xTxt = .RangeSelection.Address
        Set xRng = Application.InputBox("please select the data range", "Kutools for Excel", xTxt, , , , , 8)
        If xRng Is Nothing Then Exit Sub
        j = xRng.Columns(1).Column
        For i = 4 To xRng.Columns.Count Step 3
            'Need to recalculate the last row, as some of the final columns may not have data in all rows
            xNextRow = .Cells(.Rows.Count, j).End(xlUp).Row + 1

            .Range(xRng.Cells(1, i), xRng.Cells(xRng.Rows.Count, i + 2)).Copy .Cells(xNextRow, j)
            .Range(xRng.Cells(1, i), xRng.Cells(xRng.Rows.Count, i + 2)).Clear
    End With
End Sub

You could do this too.

Sub TransposeFormulas()
    Dim vFormulas As Variant
    Dim oSel As Range
    If TypeName(Selection) <> "Range" Then
        MsgBox "Please select a range of cells first.", _
                vbOKOnly + vbInformation, "Transpose formulas"
        Exit Sub
    End If
    Set oSel = Selection
    vFormulas = oSel.Formula
    vFormulas = Application.WorksheetFunction.Transpose(vFormulas)
    oSel.Offset(oSel.Rows.Count + 2).Resize(oSel.Columns.Count, oSel.Rows.Count).Formula = vFormulas
End Sub

See this for more info.

Laravel update model with unique validation rule for attribute

For a custom FormRequest and Laravel 5.7+ you can get the id of your updated model like this:

public function rules()
        return [
            'name' => 'required|min:5|max:255|unique:schools,name,'.\Request::instance()->id

Making a Sass mixin with optional arguments

I am new to css compilers, hope this helps,

        @mixin positionStyle($params...){

            @if $temp != null{

            @if $temp != null{

            @if $temp != null{

            @if $temp != null{

            @if $temp != null{

    @include positionStyle(absolute,30px,5px,null,null);


 top: 30px;
 right: 5px;

iPhone UITextField - Change placeholder text color

The following only with iOS6+ (as indicated in Alexander W's comment):

UIColor *color = [UIColor grayColor];
nameText.attributedPlaceholder =
   [[NSAttributedString alloc]
       initWithString:@"Full Name"

How to use select/option/NgFor on an array of objects in Angular2

I'm no expert with DOM or Javascript/Typescript but I think that the DOM-Tags can't handle real javascript object somehow. But putting the whole object in as a string and parsing it back to an Object/JSON worked for me:

interface TestObject {

  selector: 'app',
  template: `
      <h4>Select Object via 2-way binding</h4>

      <select [ngModel]="selectedObject | json" (ngModelChange)="updateSelectedValue($event)">
        <option *ngFor="#o of objArray" [value]="o | json" >{{}}</option>

      <h4>You selected:</h4> {{selectedObject }}
  directives: [FORM_DIRECTIVES]
export class App {
    this.objArray = [{name: 'foo', value: 1}, {name: 'bar', value: 1}];
    this.selectedObject = this.objArray[1];
  updateSelectedValue(event:string): void{
    this.selectedObject = JSON.parse(event);

How can I change the default credentials used to connect to Visual Studio Online (TFSPreview) when loading Visual Studio up?

I ran into this same issue. Someone had logged onto my computer and used their TFS credentials. I'm running VS2012, Windows 7, and the network admins have Credential Manager disabled.

Run this command from a command window with the same user your running visual studio as.

rundll32.exe keymgr.dll,KRShowKeyMgr

You'll see a popup with all your stored credentials. Remove the one for your TFS server.

Note: You will need to restart visual studio because it caches the tfs credentials.

Why doesn't CSS ellipsis work in table cell?

Leave your tables as they are. Just wrap the content inside the TD's with a span that has the truncation CSS applied.

/* CSS */
.truncate {
    width: 50px; /*your fixed width */
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    display: block; /* this fixes your issue */

<!-- HTML -->
                <span class="truncate">
                    Table data to be truncated if it's too long.

insert data from one table to another in mysql

If there is a primary key like "id" you have to exclude it for example my php table has: id, col2,col3,col4 columns. id is primary key so if I run this code:


I probably get this error:

#1062 - Duplicate entry '1' for key 'PRIMARY'

So here is the solution, I excluded "id" key:

INSERT INTO php ( col2,col3,col4)  (SELECT col2,col3,col4 FROM php2);

So my new php table has all php2 table rows anymore.

How to extract filename.tar.gz file

As far as I can tell, the command is correct, ASSUMING your input file is a valid gzipped tar file. Your output says that it isn't. If you downloaded the file from the internet, you probably didn't get the entire file, try again.

Without more knowledge of the source of your file, nobody here is going to be able to give you a concrete solution, just educated guesses.

Is it possible to set UIView border properties from interface builder?

Similar answer to iHulk's one, but in Swift

Add a file named UIView.swift in your project (or just paste this in any file) :

import UIKit

@IBDesignable extension UIView {
    @IBInspectable var borderColor: UIColor? {
        set {
            layer.borderColor = newValue?.cgColor
        get {
            guard let color = layer.borderColor else {
                return nil
            return UIColor(cgColor: color)
    @IBInspectable var borderWidth: CGFloat {
        set {
            layer.borderWidth = newValue
        get {
            return layer.borderWidth
    @IBInspectable var cornerRadius: CGFloat {
        set {
            layer.cornerRadius = newValue
            clipsToBounds = newValue > 0
        get {
            return layer.cornerRadius

Then this will be available in Interface Builder for every button, imageView, label, etc. in the Utilities Panel > Attributes Inspector :

Attributes Inspector

Note: the border will only appear at runtime.

'MOD' is not a recognized built-in function name

The MOD keyword only exists in the DAX language (tabular dimensional queries), not TSQL

Use % instead.

Ref: Modulo

What is the better API to Reading Excel sheets in java - JXL or Apache POI

I have used POI.

If you use that, keep on eye those cell formatters: create one and use it several times instead of creating each time for cell, it isa huge memory consumption difference or large data.

Check if a string has a certain piece of text

Here you go: ES5

var test = 'Hello World';
if( test.indexOf('World') >= 0){
  // Found world

With ES6 best way would be to use includes function to test if the string contains the looking work.

const test = 'Hello World';
if (test.includes('World')) { 
  // Found world

What is the difference between FragmentPagerAdapter and FragmentStatePagerAdapter?

Something that is not explicitly said in the documentation or in the answers on this page (even though implied by @Naruto), is that FragmentPagerAdapter will not update the Fragments if the data in the Fragment changes because it keeps the Fragment in memory.

So even if you have a limited number of Fragments to display, if you want to be able to refresh your fragments (say for example you re-run the query to update the listView in the Fragment), you need to use FragmentStatePagerAdapter.

My whole point here is that the number of Fragments and whether or not they are similar is not always the key aspect to consider. Whether or not your fragments are dynamic is also key.

Add data to JSONObject

The answer is to use a JSONArray as well, and to dive "deep" into the tree structure:

JSONArray arr = new JSONArray();
arr.put (...); // a new JSONObject()
arr.put (...); // a new JSONObject()

JSONObject json = new JSONObject();
json.put ("aoColumnDefs",arr);

bodyParser is deprecated express 4

In older versions of express, we had to use:


because body-parser was a middleware between node and express. Now we have to use it like:

app.use(bodyParser.urlencoded({ extended: false }));

C# - Substring: index and length must refer to a location within the string

Here is another suggestion. If you can prepend http:// to your url string you can do this

  string path = "";
  Uri uri = new Uri(path);            
  string expectedString = 

How to increment a JavaScript variable using a button press event

I needed to see the results of this script and was able to do so by incorporating the below:

var i=0;

function increase()
document.getElementById('boldstuff').innerHTML= +i;

<p>var = <b id="boldstuff">0</b></p>
<input type="button" onclick="increase();">

add the "script" tag above all and a closing script tag below the function end curly brace. Returning false caused firefox to hang when I tried it. All other solutions didn't show the result of the increment, in my experience.

Find control by name from Windows Forms controls

TextBox tbx = this.Controls.Find("textBox1", true).FirstOrDefault() as TextBox;
tbx.Text = "found!";

If Controls.Find is not found "textBox1" => error. You must add code.

If(tbx != null)


TextBox tbx = this.Controls.Find("textBox1", true).FirstOrDefault() as TextBox;
If(tbx != null)
   tbx.Text = "found!";

PHP - remove all non-numeric characters from a string

You can use preg_replace in this case;

$res = preg_replace("/[^0-9]/", "", "Every 6 Months" );

$res return 6 in this case.

If want also to include decimal separator or thousand separator check this example:

$res = preg_replace("/[^0-9.]/", "", "$ 123.099");

$res returns "123.099" in this case

Include period as decimal separator or thousand separator: "/[^0-9.]/"

Include coma as decimal separator or thousand separator: "/[^0-9,]/"

Include period and coma as decimal separator and thousand separator: "/[^0-9,.]/"

C++11 thread-safe queue

Adding to the accepted answer, I would say that implementing a correct multi producers / multi consumers queue is difficult (easier since C++11, though)

I would suggest you to try the (very good) lock free boost library, the "queue" structure will do what you want, with wait-free/lock-free guarantees and without the need for a C++11 compiler.

I am adding this answer now because the lock-free library is quite new to boost (since 1.53 I believe)

How do I find out what keystore my JVM is using?

We encountered this issue on a Tomcat running from a jre directory that was (almost fully) removed after an automatic jre update, so that the running jre could no longer find jre.../lib/security/cacerts because it no longer existed.

Restarting Tomcat (after changing the configuration to run from the different jre location) fixed the problem.

How to set css style to button?

You can use CssClass attribute and pass a value as a css class name

<asp:Button CssClass="button" Text="Submit" runat="server"></asp:Button>` 

     //write more styles

ORA-01036: illegal variable name/number when running query through C#

I was having the same problem in an application that I was maintaining, among all the adjustments to prepare the environment, I also spent almost an hour banging my head with this error "ORA-01036: illegal variable name / number" until I found out that the application connection was pointed to an outdated database, so the application passed two more parameters to the outdated database procedure causing the error.

Concatenating bits in VHDL

You are not allowed to use the concatenation operator with the case statement. One possible solution is to use a variable within the process:

   variable bcat : std_logic_vector(0 to 3);
   bcat := b0 & b1 & b2 & b3;
   case bcat is
      when "0000" => x <= 1;
      when others => x <= 2;
   end case;
end process;

Subset data.frame by date

The first thing you should do with date variables is confirm that R reads it as a Date. To do this, for the variable (i.e. vector/column) called Date, in the data frame called EPL2011_12, input


The output should read [1] "Date". If it doesn't, you should format it as a date by inputting

EPL2011_12$Date <- as.Date(EPL2011_12$Date, "%d-%m-%y")

Note that the hyphens in the date format ("%d-%m-%y") above can also be slashes ("%d/%m/%y"). Confirm that R sees it as a Date. If it doesn't, try a different formatting command

EPL2011_12$Date <- format(EPL2011_12$Date, format="%d/%m/%y")

Once you have it in Date format, you can use the subset command, or you can use brackets

WhateverYouWant <- EPL2011_12[EPL2011_12$Date > as.Date("2014-12-15"),]

Python display text with font & color?

Yes. It is possible to draw text in pygame:

# initialize font; must be called after 'pygame.init()' to avoid 'Font not Initialized' error
myfont = pygame.font.SysFont("monospace", 15)

# render text
label = myfont.render("Some text!", 1, (255,255,0))
screen.blit(label, (100, 100))

.htaccess redirect all pages to new domain

If the new domain you are redirecting your old site to is on a diffrent host, you can simply use a Redirect

Redirect 301 /

This will redirect all requests from olddomain to the newdomain .

Redirect directive will not work or may cause a Redirect loop if your newdomain and olddomain both are on same host, in that case you'll need to use mod-rewrite to redirect based on the requested host header.

RewriteEngine on

RewriteCond %{HTTP_HOST} ^(www\.)?olddomain\.com$
RewriteRule ^{REQUEST_URI} [NE,L,R] 

Download file using libcurl in C/C++

Just for those interested you can avoid writing custom function by passing NULL as last parameter (if you do not intend to do extra processing of returned data).
In this case default internal function is used.



#include <stdio.h>
#include <curl/curl.h>

int main(void)
    CURL *curl;
    FILE *fp;
    CURLcode res;
    char *url = "";
    char outfilename[FILENAME_MAX] = "page.html";
    curl = curl_easy_init();                                                                                                                                                                                                                                                           
    if (curl)
        fp = fopen(outfilename,"wb");
        curl_easy_setopt(curl, CURLOPT_URL, url);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, NULL);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
        res = curl_easy_perform(curl);
    return 0;

How to count instances of character in SQL Column

try this

declare @v varchar(250) = 'test.a,1  ;hheuw-20;'
-- LF   ;
select len(replace(@v,';','11'))-len(@v)

Python integer incrementing with ++

Simply put, the ++ and -- operators don't exist in Python because they wouldn't be operators, they would have to be statements. All namespace modification in Python is a statement, for simplicity and consistency. That's one of the design decisions. And because integers are immutable, the only way to 'change' a variable is by reassigning it.

Fortunately we have wonderful tools for the use-cases of ++ and -- in other languages, like enumerate() and itertools.count().

How to enter in a Docker container already running with a new TTY

nsenter does that. However I also needed to enter a container in a simple way and nsenter didn't suffice for my needs. It was buggy in some occasions (black screen plus -wd flag not working). Furthermore I wanted to login as a specific user and in a specific directory.

I ended up making my own tool to enter containers. You can find it at:

Its usage is as easy as

./docker-enter [-u <user>] [-d <directory>] <container ID>

How to use DbContext.Database.SqlQuery<TElement>(sql, params) with stored procedure? EF Code First CTP5

I use this method:

var results = this.Database.SqlQuery<yourEntity>("EXEC [ent].[GetNextExportJob] {0}", ProcessorID);

I like it because I just drop in Guids and Datetimes and SqlQuery performs all the formatting for me.

How to print Two-Dimensional Array like table


Sorry for that.

you code is work. but its had some problem with Array row and columns

here i correct your code this work correctly, you can try this ..

public static void printMatrix(int size, int row, int[][] matrix) {

    for (int i = 0; i < 7 * matrix[row].length; i++) {

    for (int i = 1; i <= matrix[row].length; i++) {
        System.out.printf("| %4d ", matrix[row][i - 1]);

    if (row == size - 1) {

        // when we reach the last row,
        // print bottom line "---------"

        for (int i = 0; i < 7 * matrix[row].length; i++) {


public static void length(int[][] matrix) {

    int rowsLength = matrix.length;

    for (int k = 0; k < rowsLength; k++) {

        printMatrix(rowsLength, k, matrix);



public static void main(String[] args) {

    int[][] matrix = { { 1, 2, 5 }, { 3, 4, 6 }, { 7, 8, 9 }




and out put look like

|    1 |    2 |    5 |
|    3 |    4 |    6 |
|    7 |    8 |    9 |

show more/Less text with just HTML and JavaScript

Try to toggle height.

function toggleTextArea()
  var limitedHeight = '40px';
  var targetEle = document.getElementById("textarea"); = ( === '') ? limitedHeight : '';

How to add multiple columns to pandas dataframe in one assignment?

use of list comprehension, pd.DataFrame and pd.concat

            [[np.nan, 'dogs', 3] for _ in range(df.shape[0])],
            df.index, ['column_new_1', 'column_new_2','column_new_3']
    ], axis=1)

enter image description here

How to make clang compile to llvm IR

Given some C/C++ file foo.c:

> clang -S -emit-llvm foo.c

Produces foo.ll which is an LLVM IR file.

The -emit-llvm option can also be passed to the compiler front-end directly, and not the driver by means of -cc1:

> clang -cc1 foo.c -emit-llvm

Produces foo.ll with the IR. -cc1 adds some cool options like -ast-print. Check out -cc1 --help for more details.

To compile LLVM IR further to assembly, use the llc tool:

> llc foo.ll

Produces foo.s with assembly (defaulting to the machine architecture you run it on). llc is one of the LLVM tools - here is its documentation.

Getting full JS autocompletion under Sublime Text

I developed a new plugin called JavaScript Enhancements, that you can find on Package Control. It uses Flow (javascript static type checker from Facebook) under the hood.

Furthermore, it offers smart javascript autocomplete (compared to my other plugin JavaScript Completions), real-time errors, code refactoring and also a lot of features about creating, developing and managing javascript projects.

See the Wiki to know all the features that it offers!

An introduction to this plugin could be found in this article: Turn Sublime Text 3 into a JavaScript IDE

Just some quick screenshots:

What is "with (nolock)" in SQL Server?

NOLOCK is equivalent to READ UNCOMMITTED, however Microsoft says you should not use it for UPDATE or DELETE statements:

For UPDATE or DELETE statements: This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.

This article applies to SQL Server 2005, so the support for NOLOCK exists if you are using that version. In order to future-proof you code (assuming you've decided to use dirty reads) you could use this in your stored procedures:


List all devices, partitions and volumes in Powershell

To get all of the file system drives, you can use the following command:

gdr -PSProvider 'FileSystem'

gdr is an alias for Get-PSDrive, which includes all of the "virtual drives" for the registry, etc.

How to get JSON data from the URL (REST API) to UI using jQuery or plain JavaScript?

Send a ajax request to your server like this in your js and get your result in success function.

            url: "/rest/abc",
            type: "GET",

            contentType: 'application/json; charset=utf-8',
            success: function(resultData) {
                //here is your json.
                  // process it

            error : function(jqXHR, textStatus, errorThrown) {

            timeout: 120000,

at server side send response as json type.

And you can use jQuery.getJSON for your application.

How is a CRC32 checksum calculated?

A CRC is pretty simple; you take a polynomial represented as bits and the data, and divide the polynomial into the data (or you represent the data as a polynomial and do the same thing). The remainder, which is between 0 and the polynomial is the CRC. Your code is a bit hard to understand, partly because it's incomplete: temp and testcrc are not declared, so it's unclear what's being indexed, and how much data is running through the algorithm.

The way to understand CRCs is to try to compute a few using a short piece of data (16 bits or so) with a short polynomial -- 4 bits, perhaps. If you practice this way, you'll really understand how you might go about coding it.

If you're doing it frequently, a CRC is quite slow to compute in software. Hardware computation is much more efficient, and requires just a few gates.

NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder

You have included the dependency for sflj's api, but not the dependency for the implementation of the api, that is a separate jar, you could try slf4j-simple-1.6.1.jar.

PHP Fatal error: Cannot access empty property

First, don't declare variables using var, but

public $my_value;

Then you can access it using


and not


Setting selected option in laravel form

Just Simply paste this code you will get the desired output that you needed.

 {{ Form::select ('myselect', ['1' => 'Item 1', '2' => 'Item 2'], 2 , ['id' =>'myselect']) }}` `

How to get week number in Python?

There are many systems for week numbering. The following are the most common systems simply put with code examples:

  • ISO: First week starts with Monday and must contain the January 4th. The ISO calendar is already implemented in Python:

    >>> from datetime import date
    >>> date(2014, 12, 29).isocalendar()[:2]
    (2015, 1)
  • North American: First week starts with Sunday and must contain the January 1st. The following code is my modified version of Python's ISO calendar implementation for the North American system:

    from datetime import date
    def week_from_date(date_object):
        date_ordinal = date_object.toordinal()
        year = date_object.year
        week = ((date_ordinal - _week1_start_ordinal(year)) // 7) + 1
        if week >= 52:
            if date_ordinal >= _week1_start_ordinal(year + 1):
                year += 1
                week = 1
        return year, week
    def _week1_start_ordinal(year):
        jan1 = date(year, 1, 1)
        jan1_ordinal = jan1.toordinal()
        jan1_weekday = jan1.weekday()
        week1_start_ordinal = jan1_ordinal - ((jan1_weekday + 1) % 7)
        return week1_start_ordinal
    >>> from datetime import date
    >>> week_from_date(date(2014, 12, 29))
    (2015, 1)
  • MMWR (CDC): First week starts with Sunday and must contain the January 4th. I created the epiweeks package specifically for this numbering system (also has support for the ISO system). Here is an example:
    >>> from datetime import date
    >>> from epiweeks import Week
    >>> Week.fromdate(date(2014, 12, 29))
    (2014, 53)

How to pass event as argument to an inline event handler in JavaScript?

You don't need to pass this, there already is the event object passed by default automatically, which contains which has the object it's coming from. You can lighten your syntax:


<p onclick="doSomething()">

Will work with this:

function doSomething(){

You don't need to instantiate the event object, it's already there. Try it out. And will contain the entire object calling it, which you were referencing as "this" before.

Now if you dynamically trigger doSomething() from somewhere in your code, you will notice that event is undefined. This is because it wasn't triggered from an event of clicking. So if you still want to artificially trigger the event, simply use dispatchEvent:

document.getElementById('element').dispatchEvent(new CustomEvent("click", {'bubbles': true}));

Then doSomething() will see event and as per usual!

No need to pass this everywhere, and you can keep your function signatures free from wiring information and simplify things.

Android M - check runtime permission - how to determine if the user checked "Never ask again"?

You can use




See the example below:

Check if it has permission when the user clicks the button:

public void onClick(View v) {
    if (v.getId() == {
        if (Build.VERSION.SDK_INT < 23) { // API < 23 don't need to ask permission
            navigateTo(MainActivity.class); // Navigate to activity to change photos
        } else {
            if (ContextCompat.checkSelfPermission(SettingsActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                    != PackageManager.PERMISSION_GRANTED) {
                // Permission is not granted yet. Ask for permission...
            } else {
                // Permission is already granted, good to go :)

When the user answer the permission dialog box we will go to onRequestPermissionResult:

public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        // Case 1. Permission is granted.  
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {  
            if (ContextCompat.checkSelfPermission(SettingsActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                    == PackageManager.PERMISSION_GRANTED) {
                // Before navigating, I still check one more time the permission for good practice.
        } else { // Case 2. Permission was refused
            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                // Case 2.1. shouldShowRequest... returns true because the
                // permission was denied before. If it is the first time the app is running we will 
                // end up in this part of the code. Because he need to deny at least once to get 
                // to onRequestPermissionsResult. 
                Snackbar snackbar = Snackbar.make(findViewById(, R.string.you_must_verify_permissions_to_send_media, Snackbar.LENGTH_LONG);
                snackbar.setAction("VERIFY", new View.OnClickListener() {
                    public void onClick(View v) {
                                , new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}
                                , WRITE_EXTERNAL_PERMISSION_REQUEST_CODE);
            } else {
                // Case 2.2. Permission was already denied and the user checked "Never ask again". 
                // Navigate user to settings if he choose to allow this time.
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                        .setPositiveButton(getString(R.string.settings), new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int which) {
                                Intent settingsIntent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
                                Uri uri = Uri.fromParts("package", getPackageName(), null);
                                startActivityForResult(settingsIntent, 7);
                        .setNegativeButton(getString(R.string.not_now), null);
                Dialog dialog = builder.create();


Flutter : Vertically center column



SQL recursive query on self referencing table (Oracle)

Do you want to do this?

SELECT id, parent_id, name, 
 (select Name from tbl where id = t.parent_id) parent_name
FROM tbl t start with id = 1 CONNECT BY PRIOR id = parent_id

Edit Another option based on OMG's one (but I think that will perform equally):

  AS parent_name,
  AS parent_id
    (select id, parent_id, name
    from tbl
    start with id = 1 
    connect by prior id = parent_id) t1
    left join
    tbl t2 on = t1.parent_id

Interface type check with Typescript

I would like to point out that TypeScript does not provide a direct mechanism for dynamically testing whether an object implements a particular interface.

Instead, TypeScript code can use the JavaScript technique of checking whether an appropriate set of members are present on the object. For example:

var obj : any = new Foo();

if (obj.someInterfaceMethod) {

How do I call ::CreateProcess in c++ to launch a Windows executable?

On a semi-related note, if you want to start a process that has more privileges than your current process (say, launching an admin app, which requires Administrator rights, from the main app running as a normal user), you can't do so using CreateProcess() on Vista since it won't trigger the UAC dialog (assuming it is enabled). The UAC dialog is triggered when using ShellExecute(), though.

How to replace text in a column of a Pandas dataframe?

Use the vectorised str method replace:

In [30]:

df['range'] = df['range'].str.replace(',','-')
0    (2-30)
1  (50-290)


So if we look at what you tried and why it didn't work:


from the docs we see this desc:

str or regex: str: string exactly matching to_replace will be replaced with value

So because the str values do not match, no replacement occurs, compare with the following:

In [43]:

df = pd.DataFrame({'range':['(2,30)',',']})
df['range'].replace(',','-', inplace=True)
0    (2,30)
1         -
Name: range, dtype: object

here we get an exact match on the second row and the replacement occurs.

HashMap - getting First Key value

Also a nice way of doing this :)

Map<Integer,JsonObject> requestOutput = getRequestOutput(client,post);
int statusCode = requestOutput.keySet().stream().findFirst().orElseThrow(() -> new RuntimeException("Empty"));

Parse JSON from JQuery.ajax success data

The data is coming back as the string representation of the JSON and you aren't converting it back to a JavaScript object. Set the dataType to just 'json' to have it converted automatically.

mkdir -p functionality in Python

import os
from os.path import join as join_paths

def mk_dir_recursive(dir_path):

    if os.path.isdir(dir_path):
    h, t = os.path.split(dir_path)  # head/tail
    if not os.path.isdir(h):

    new_path = join_paths(h, t)
    if not os.path.isdir(new_path):

based on @Dave C's answer but with a bug fixed where part of the tree already exists

Python SQLite: database is locked

Easy solution: check once if you have opened the database in another window or in another terminal. That also locks your database. In my case, I closed all the other terminals that were locking the database (a terminal tab in Pycharm). Check each tab of the terminals of your IDE as well if there is a terminal that left the database open. exit() all the terminals should work unlocking the database.

How to run certain task every day at a particular time using ScheduledExecutorService?

In Java 8:

scheduler = Executors.newScheduledThreadPool(1);

//Change here for the hour you want       
Long, ChronoUnit.MINUTES);
scheduler.scheduleAtFixedRate(this, midnight, 1440, TimeUnit.MINUTES);

The server encountered an internal error that prevented it from fulfilling this request - in servlet 3.0

I found solution. It works fine when I throw away next line from form:


And now it pass all parameters at request ok:

 <form action="/registration" method="post">
   <%-- error messages --%>
   <div class="form-group">
    <c:forEach items="${registrationErrors}" var="error">
    <p class="error">${error}</p>

How to enable C++11/C++0x support in Eclipse CDT?

I had several issues too (Ubuntu 13.04 64-bit, g++-4.8, eclipse Juno 3.8.1, CDT 6.0.0). A lot of things are mentioned above, sorry to repeat those, but additionally I had problems utilizing


as part of c++11 (adding -pthread for the linker solves that issue). Anyway, finally these settings worked fine:

Project -> Properties -> C/C++ Build -> Settings -> Miscellaneous. Add the


flag for the GCC and G++ compilers. Click Apply.

For the linker, same window, Miscellaneous, Linker flags, added the


flag. Shared library settings, Shared object name, add the


flag too. Click Apply.

C/C++ General -> Paths and symbols -> Symbols TAB, GNU C++ selected, Add the


(no value)

flag. Click Apply.

C/C++ General -> Preprocessor Include paths.. -> Providers tab : check

CDT GCC built-in Compiler Settings

and for "Command to get compiler specs", add the


flag. Uncheck Share. Click Apply.

CDT Managages Build Setting Entries, check this too. Uncheck the two others. Click Apply.

Going back to the Entries tab, GNU C++ CDT Managages Build Setting Entries, you should now see your added



That's it. When coding, typing


can now auto-complete the thread class for instance, builds should work fine and there should be no

std::system_error'what(): Enable multithreading to use std::thread: Operation not permitted

at runtime.

Can a variable number of arguments be passed to a function?

Adding to unwinds post:

You can send multiple key-value args too.

def myfunc(**kwargs):
    # kwargs is a dictionary.
    for k,v in kwargs.iteritems():
         print "%s = %s" % (k, v)

myfunc(abc=123, efh=456)
# abc = 123
# efh = 456

And you can mix the two:

def myfunc2(*args, **kwargs):
   for a in args:
       print a
   for k,v in kwargs.iteritems():
       print "%s = %s" % (k, v)

myfunc2(1, 2, 3, banan=123)
# 1
# 2
# 3
# banan = 123

They must be both declared and called in that order, that is the function signature needs to be *args, **kwargs, and called in that order.

Powershell: convert string to number

Simply divide the Variable containing Numbers as a string by 1. PowerShell automatically convert the result to an integer.

$a = 15; $b = 2; $a + $b --> 152

But if you divide it before:

$a/1 + $b/1 --> 17

Does C have a string type?

To note it in the languages you mentioned:


String str = new String("Hello");


str = "Hello"

Both Java and Python have the concept of a "string", C does not have the concept of a "string". C has character arrays which can come in "read only" or manipulatable.


char * str = "Hello";  // the string "Hello\0" is pointed to by the character pointer
                       // str. This "string" can not be modified (read only)


char str[] = "Hello";  // the characters: 'H''e''l''l''o''\0' have been copied to the 
                       // array str. You can change them via: str[x] = 't'

A character array is a sequence of contiguous characters with a unique sentinel character at the end (normally a NULL terminator '\0'). Note that the sentinel character is auto-magically appended for you in the cases above.

The SQL OVER() clause - when and why is it useful?

The OVER clause when combined with PARTITION BY state that the preceding function call must be done analytically by evaluating the returned rows of the query. Think of it as an inline GROUP BY statement.

OVER (PARTITION BY SalesOrderID) is stating that for SUM, AVG, etc... function, return the value OVER a subset of the returned records from the query, and PARTITION that subset BY the foreign key SalesOrderID.

So we will SUM every OrderQty record for EACH UNIQUE SalesOrderID, and that column name will be called 'Total'.

It is a MUCH more efficient means than using multiple inline views to find out the same information. You can put this query within an inline view and filter on Total then.

FROM (your query) inlineview
WHERE Total < 200

Can't install Scipy through pip

  1. Download SciPy from
  2. Go into the directory the downloaded file is in and pip install the file.
  3. Go to python shell, run import scipy; it worked for me with no errors.

How to apply !important using .css()?

The safest workaround to this is to add a class and then do the magic in CSS :-), addClass() and removeClass() should do the work.

How can I get the MAC and the IP address of a connected client in PHP?

For windows server I think u can use this:

echo exec('getmac');

Convert an enum to List<string>

I want to add another solution: In my case, I need to use a Enum group in a drop down button list items. So they might have space, i.e. more user friendly descriptions needed:

  public enum CancelReasonsEnum
    [Description("In rush")]
    [Description("Need more coffee")]
    [Description("Call me back in 5 minutes!")]

In a helper class (HelperMethods) I created the following method:

 public static List<string> GetListOfDescription<T>() where T : struct
        Type t = typeof(T);
        return !t.IsEnum ? null : Enum.GetValues(t).Cast<Enum>().Select(x => x.GetDescription()).ToList();

When you call this helper you will get the list of item descriptions.

 List<string> items = HelperMethods.GetListOfDescription<CancelReasonEnum>();

ADDITION: In any case, if you want to implement this method you need :GetDescription extension for enum. This is what I use.

 public static string GetDescription(this Enum value)
        Type type = value.GetType();
        string name = Enum.GetName(type, value);
        if (name != null)
            FieldInfo field = type.GetField(name);
            if (field != null)
                DescriptionAttribute attr =Attribute.GetCustomAttribute(field,typeof(DescriptionAttribute)) as DescriptionAttribute;
                if (attr != null)
                    return attr.Description;
        return null;
        /* how to use
            MyEnum x = MyEnum.NeedMoreCoffee;
            string description = x.GetDescription();


100% width in React Native Flexbox

Simply add alignSelf: "stretch" to your item's stylesheet.

line1: {
    backgroundColor: '#FDD7E4',
    alignSelf: 'stretch',
    textAlign: 'center',

Laravel-5 'LIKE' equivalent (Eloquent)

I think this is better, following the good practices of passing parameters to the query:

BookingDates::whereRaw('email = ? or name like ?', [$request->email,"%{$request->name}%"])->get();

You can see it in the documentation, Laravel 5.5.

You can also use the Laravel scout and make it easier with search. Here is the documentation.

Embed YouTube video - Refused to display in a frame because it set 'X-Frame-Options' to 'SAMEORIGIN'

The YouTube URL in src must have and use the embed endpoint instead of watch, so for instance let’s say you want to embed this YouTube video: (browser's URL).

You should use the embed endpoint, so the URL now should be something like Use this value as the URL in the src attribute inside the iframe tag in your HTML code, for example:

<iframe width="853" height="480" src="" frameborder="0" allowfullscreen ng-show="showvideo"></iframe>

So just replace with and of course check for your video's ID. In this sample, my video ID is P6N9782MzFQ.

How to get the file name from a full path using JavaScript?

I use:

var lastPart = path.replace(/\\$/,'').split('\\').pop();

It replaces the last \ so it also works with folders.

How to use Jackson to deserialise an array of objects

try {
    ObjectMapper mapper = new ObjectMapper();
    JsonFactory f = new JsonFactory();
    List<User> lstUser = null;
    JsonParser jp = f.createJsonParser(new File("C:\\maven\\user.json"));
    TypeReference<List<User>> tRef = new TypeReference<List<User>>() {};
    lstUser = mapper.readValue(jp, tRef);
    for (User user : lstUser) {

} catch (JsonGenerationException e) {
} catch (JsonMappingException e) {
} catch (IOException e) {

Getting user input

In python 3.x, use input() instead of raw_input()

How to return multiple values in one column (T-SQL)?

Well... I see that an answer was already accepted... but I think you should see another solutions anyway:

DECLARE @UserAliases TABLE(UserId INT , Alias VARCHAR(10))
INSERT INTO @UserAliases (UserId,Alias) SELECT 1,'MrX'

/* QUERY */
;WITH tmp AS ( SELECT DISTINCT UserId FROM @UserAliases )
    LEFT(tmp.UserId, 10) +
    '/ ' +
            (   SELECT ', '+Alias 
                FROM @UserAliases 
                WHERE UserId = tmp.UserId 
                FOR XML PATH('') 
            , 1, 2, ''
        ) AS [UserId/Alias]
FROM tmp

/* -- OUTPUT
  1/ MrX, MrY, MrA
  2/ Abc, Xyz    

Simple proof that GUID is not unique

The odds of a bug in the GUID generating code are much higher than the odds of the algorithm generating a collision. The odds of a bug in your code to test the GUIDs is even greater. Give up.

how to create dynamic two dimensional array in java?

One more example for 2 dimension String array:

public void arrayExam() {
    List<String[]> A = new ArrayList<String[]>();
    A.add(new String[] {"Jack","good"});
    A.add(new String[] {"Mary","better"});
    A.add(new String[] {"Kate","best"});
    for (String[] row : A) {
        Log.i(TAG,row[0] + "->" + row[1]);


17467 08-02 19:24:40.518  8456  8456 I MyExam  : Jack->good
17468 08-02 19:24:40.518  8456  8456 I MyExam  : Mary->better
17469 08-02 19:24:40.518  8456  8456 I MyExam  : Kate->best

Using Mockito to mock classes with generic parameters

As the other answers mentioned, there's not a great way to use the mock() & spy() methods directly without unsafe generics access and/or suppressing generics warnings.

There is currently an open issue in the Mockito project (#1531) to add support for using the mock() & spy() methods without generics warnings. The issue was opened in November 2018, but there aren't any indications whether it will be prioritized.

Check if the file exists using VBA

just get rid of those speech marks

Sub test()

Dim thesentence As String

thesentence = InputBox("Type the filename with full extension", "Raw Data File")

Range("A1").Value = thesentence

If Dir(thesentence) <> "" Then
    MsgBox "File exists."
    MsgBox "File doesn't exist."
End If

End Sub

This is the one I like:

Option Explicit

Enum IsFileOpenStatus
    ExistsAndClosedOrReadOnly = 0
    ExistsAndOpenSoBlocked = 1
    NotExists = 2
End Enum

Function IsFileReadOnlyOpen(FileName As String) As IsFileOpenStatus

With New FileSystemObject
    If Not .FileExists(FileName) Then
        IsFileReadOnlyOpen = 2  '  NotExists = 2
        Exit Function 'Or not - I don't know if you want to create the file or exit in that case.
    End If
End With

Dim iFilenum As Long
Dim iErr As Long
On Error Resume Next
    iFilenum = FreeFile()
    Open FileName For Input Lock Read As #iFilenum
    Close iFilenum
    iErr = Err
On Error GoTo 0

Select Case iErr
    Case 0: IsFileReadOnlyOpen = 0 'ExistsAndClosedOrReadOnly = 0
    Case 70: IsFileReadOnlyOpen = 1 'ExistsAndOpenSoBlocked = 1
    Case Else: IsFileReadOnlyOpen = 1 'Error iErr
End Select

End Function    'IsFileReadOnlyOpen

How to form tuple column from two columns in Pandas

Pandas has the itertuples method to do exactly this:

list(df[['lat', 'long']].itertuples(index=False, name=None))

TypeScript for ... of with index / key?

You can use the TypeScript operator to access the index when dealing with collections.

var test = [7,8,9];
for (var i in test) {
   console.log(i + ': ' + test[i]);


 0: 7
 1: 8
 2: 9

See Demo

How to join two sets in one line without using "|"

Suppose you have 2 lists

 A = [1,2,3,4]
 B = [3,4,5,6]

so you can find A Union B as follow

 union = set(A).union(set(B))

also if you want to find intersection and non-intersection you do that as follow

 intersection = set(A).intersection(set(B))
 non_intersection = union - intersection

How do I remove blank elements from an array?

Update with a strict with join & split

cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"]
cities.join(' ').split

Result will be:

["Kathmandu", "Pokhara", "Dharan", "Butwal"]

Note that: this doesn't work with a city with spaces

How to square all the values in a vector in R?

This will also work

newData <- data*data

Why does using an Underscore character in a LIKE filter give me all the results?

Underscore is a wildcard for something. for example 'A_%' will look for all match that Start whit 'A' and have minimum 1 extra character after that

Python list subtraction operation

if duplicate and ordering items are problem :

[i for i in a if not i in b or b.remove(i)]

a = [1,2,3,3,3,3,4]
b = [1,3]
result: [2, 3, 3, 3, 4]

How can I trim leading and trailing white space?

Ad 1) To see white spaces you could directly call with modified arguments:

print(head(iris), quote=TRUE)
#   Sepal.Length Sepal.Width Petal.Length Petal.Width  Species
# 1        "5.1"       "3.5"        "1.4"       "0.2" "setosa"
# 2        "4.9"       "3.0"        "1.4"       "0.2" "setosa"
# 3        "4.7"       "3.2"        "1.3"       "0.2" "setosa"
# 4        "4.6"       "3.1"        "1.5"       "0.2" "setosa"
# 5        "5.0"       "3.6"        "1.4"       "0.2" "setosa"
# 6        "5.4"       "3.9"        "1.7"       "0.4" "setosa"

See also ? for other options.

Python datetime to string without microsecond component

In Python 3.6:

from datetime import datetime' ', 'seconds')
'2017-01-11 14:41:33'

How do I set path while saving a cookie value in JavaScript?

For access cookie in whole app (use path=/):

function createCookie(name,value,days) {
    if (days) {
        var date = new Date();
        var expires = "; expires="+date.toGMTString();
    else var expires = "";
    document.cookie = name+"="+value+expires+"; path=/"; 


If you set path=/,
Now the cookie is available for whole application/domain. If you not specify the path then current cookie is save just for the current page you can't access it on another page(s).

For more info read- (Domain and path part)

If you use cookies in jquery by plugin jquery-cookie:

$.cookie('name', 'value', { expires: 7, path: '/' });
$.cookie('name', 'value', { path: '/' });

Run php function on button click

Do this:

<input type="button" name="test" id="test" value="RUN" /><br/>


function testfun()
   echo "Your test function on button click is working";

JavaScript equivalent to printf/String.Format

+1 Zippo with the exception that the function body needs to be as below or otherwise it appends the current string on every iteration:

String.prototype.format = function() {
    var formatted = this;
    for (var arg in arguments) {
        formatted = formatted.replace("{" + arg + "}", arguments[arg]);
    return formatted;

Git: Merge a Remote branch locally

Maybe you want to track the remote branch with a local branch:

  1. Create a new local branch: git branch new-local-branch
  2. Set this newly created branch to track the remote branch: git branch --set-upstream-to=origin/remote-branch new-local-branch
  3. Enter into this branch: git checkout new-local-branch
  4. Pull all the contents of the remote branch into the local branch: git pull

How can I repeat a character in Bash?

This is the longer version of what Eliah Kagan was espousing:

while [ $(( i-- )) -gt 0 ]; do echo -n "  "; done

Of course you can use printf for that as well, but not really to my liking:

printf "%$(( i*2 ))s"

This version is Dash compatible:

until [ $(( i=i-1 )) -lt 0 ]; do echo -n "  "; done

with i being the initial number.

How to link external javascript file onclick of button

I have to agree with the comments above, that you can't call a file, but you could load a JS file like this, I'm unsure if it answers your question but it may help... oh and I've used a link instead of a button in my example...

<a href='linkhref.html' id='mylink'>click me</a>

<script type="text/javascript">

var myLink = document.getElementById('mylink');

myLink.onclick = function(){

    var script = document.createElement("script");
    script.type = "text/javascript";
    script.src = "Public/Scripts/filename.js."; 
    return false;



What is the significance of #pragma marks? Why do we need #pragma marks?

#pragma mark directives show up in Xcode in the menus for direct access to methods. They have no impact on the program at all.

For example, using it with Xcode 4 will make those items appear directly in the Jump Bar.

There is a special pragma mark - which creates a line.

enter image description here

How to remove jar file from local maven repository which was added with install:install-file?

At least on the current maven version you need to add the switch -DreResolve=false if you intend to remove the dependencies from your local repo without re-downloading them.

mvn dependency:purge-local-repository -DreResolve=false

removes the dependencies without downloading them again.

escaping question mark in regex javascript

Whenever you have a known pattern (i.e. you do not use a variable to build a RegExp), use literal regex notation where you only need to use single backslashes to escape special regex metacharacters:

var re = /I like your Apartment\. Could we schedule a viewing\?/g;
                               ^^                            ^^

Whenever you need to build a RegExp dynamically, use RegExp constructor notation where you MUST double backslashes for them to denote a literal backslash:

var questionmark_block = "\\?"; // A literal ?
var initial_subpattern = "I like your Apartment\\. Could we schedule a viewing"; // Note the dot must also be escaped to match a literal dot
var re = new RegExp(initial_subpattern + questionmark_block, "g");

And if you use the String.raw string literal you may use \ as is (see an example of using a template string literal where you may put variables into the regex pattern):

const questionmark_block = String.raw`\?`; // A literal ?
const initial_subpattern = "I like your Apartment\\. Could we schedule a viewing";
const re = new RegExp(`${initial_subpattern}${questionmark_block}`, 'g'); // Building pattern from two variables
console.log(re); // => /I like your Apartment\. Could we schedule a viewing\?/g

A must-read: RegExp: Description at MDN.

java.lang.NoClassDefFoundError: Could not initialize class XXX

I encounter the same problem. I inited a bean object in static block like below:

static {
        mqttConfiguration = SpringBootBeanUtils.<MqttConfiguration>getBean(MqttConfiguration.class);
    }catch (Throwable e){

Just because the process the my bean obejct inition caused a NPE, I get trouble into it. So I think you should check you static code block carefully.

ggplot2 line chart gives "geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?"

I found this can also occur if the most of the data plotted is outside of the axis limits. In that case, adjust the axis scales accordingly.

How do I make CMake output into a 'bin' dir?

English is not my native language; please excuse typing errors.

use this line config :
place your any CMakeLists.txt project.
this ${PROJECT_SOURCE_DIR} is your current source directory where project place .
and if wander why is ${EXECUTABLE_OUTPUT_PATH}
check this file CMakeCache.txt then search the key word output path,
all the variables define here , it would give a full explanation of the project all setting·

How to download image using requests

I'm going to post an answer as I don't have enough rep to make a comment, but with wget as posted by Blairg23, you can also provide an out parameter for the path., out=path)

multiple packages in context:component-scan, spring config

For Example you have the package "" and you have multiple packages inside it, You can use like


What rules does software version numbering follow?

The usual method I have seen is X.Y.Z, which generally corresponds to major.minor.patch:

  • Major version numbers change whenever there is some significant change being introduced. For example, a large or potentially backward-incompatible change to a software package.
  • Minor version numbers change when a new, minor feature is introduced or when a set of smaller features is rolled out.
  • Patch numbers change when a new build of the software is released to customers. This is normally for small bug-fixes or the like.

Other variations use build numbers as an additional identifier. So you may have a large number for if you have many revisions that are tested between releases. I use a couple of packages that are identified by year/month or year/release. Thus, a release in the month of September of 2010 might be 2010.9 or 2010.3 for the 3rd release of this year.

There are many variants to versioning. It all boils down to personal preference.

For the "1.3v1.1", that may be two different internal products, something that would be a shared library / codebase that is rev'd differently from the main product; that may indicate version 1.3 for the main product, and version 1.1 of the internal library / package. Server returned HTTP response code: 500

I have encountered the same problem and found out the solution.

You may look within the first server response and see if the server sent you a cookie.

To check if the server sent you a cookie, you can use HttpURLConnection#getHeaderFields() and look for headers named "Set-Cookie".

If existing, here's the solution for your problem. 100% Working for this case!

+1 if it worked for you.

How can I schedule a daily backup with SQL Server Express?

The folks at MSSQLTips have some very helpful articles, the one most relevant for this is "Automating SQL Server 2005 Express Backups and Deletion of Older Backup Files"

The basic approach is to set up two tasks using the Windows Task Scheduler. One task runs a TSQL script that generates separate backup files for all MSSQL databases (except TEMPDB) with the database name and a date/time stamp in the file name into a specified directory. The second task runs a VBScript script that goes through that directory and deletes all files with a .BAK extension that are more than 3 days old.

Both scripts require minor editing for your environment (paths, how long to keep those database dumps) but are very close to drop-in-and-run.

Note that there are possible security implications if you're sloppy with these or with directory permissions, since they are plain text files that will need to run with some level of privilege. Don't be sloppy.

Format timedelta to string

timedelta to string, use for print running time info.

def strfdelta_round(tdelta, round_period='second'):
  """timedelta to string,  use for measure running time
  attend period from days downto smaller period, round to minimum period
  omit zero value period  
  period_names = ('day', 'hour', 'minute', 'second', 'millisecond')
  if round_period not in period_names:
    raise Exception(f'round_period "{round_period}" invalid, should be one of {",".join(period_names)}')
  period_seconds = (86400, 3600, 60, 1, 1/pow(10,3))
  period_desc = ('days', 'hours', 'mins', 'secs', 'msecs')
  round_i = period_names.index(round_period)
  s = ''
  remainder = tdelta.total_seconds()
  for i in range(len(period_names)):
    q, remainder = divmod(remainder, period_seconds[i])
    if int(q)>0:
      if not len(s)==0:
        s += ' '
      s += f'{q:.0f} {period_desc[i]}'
    if i==round_i:
    if i==round_i+1:
      s += f'{remainder} {period_desc[round_i]}'
  return s

e.g. auto omit zero leading period:

>>> td = timedelta(days=0, hours=2, minutes=5, seconds=8, microseconds=3549)
>>> strfdelta_round(td, 'second')
'2 hours 5 mins 8 secs'

or omit middle zero period:

>>> td = timedelta(days=2, hours=0, minutes=5, seconds=8, microseconds=3549)
>>> strfdelta_round(td, 'millisecond')
'2 days 5 mins 8 secs 3 msecs'

or round to minutes, omit below minutes:

>>> td = timedelta(days=1, hours=2, minutes=5, seconds=8, microseconds=3549)
>>> strfdelta_round(td, 'minute')
'1 days 2 hours 5 mins'

How to send email to multiple address using System.Net.Mail

MailAddress fromAddress = new MailAddress  (fromMail,fromName);
MailAddress toAddress = new MailAddress(toMail,toName);
MailMessage message = new MailMessage(fromAddress,toAddress);
message.Subject = subject;
message.Body = body;
SmtpClient smtp = new SmtpClient()
    Host = host, Port = port,
    enabHost = "",
    Port = 25,
    EnableSsl = true,
    UseDefaultCredentials = true,
    Credentials = new  NetworkCredentials (fromMail, password)

How do I convert uint to int in C#?

Assuming you want to simply lift the 32bits from one type and dump them as-is into the other type:

uint asUint = unchecked((uint)myInt);
int asInt = unchecked((int)myUint);

The destination type will blindly pick the 32 bits and reinterpret them.

Conversely if you're more interested in keeping the decimal/numerical values within the range of the destination type itself:

uint asUint = checked((uint)myInt);
int asInt = checked((int)myUint);

In this case, you'll get overflow exceptions if:

  • casting a negative int (eg: -1) to an uint
  • casting a positive uint between 2,147,483,648 and 4,294,967,295 to an int

In our case, we wanted the unchecked solution to preserve the 32bits as-is, so here are some examples:


int => uint

int....: 0000000000 (00-00-00-00)
asUint.: 0000000000 (00-00-00-00)
int....: 0000000001 (01-00-00-00)
asUint.: 0000000001 (01-00-00-00)
int....: -0000000001 (FF-FF-FF-FF)
asUint.: 4294967295 (FF-FF-FF-FF)
int....: 2147483647 (FF-FF-FF-7F)
asUint.: 2147483647 (FF-FF-FF-7F)
int....: -2147483648 (00-00-00-80)
asUint.: 2147483648 (00-00-00-80)

uint => int

uint...: 0000000000 (00-00-00-00)
asInt..: 0000000000 (00-00-00-00)
uint...: 0000000001 (01-00-00-00)
asInt..: 0000000001 (01-00-00-00)
uint...: 2147483647 (FF-FF-FF-7F)
asInt..: 2147483647 (FF-FF-FF-7F)
uint...: 4294967295 (FF-FF-FF-FF)
asInt..: -0000000001 (FF-FF-FF-FF)


int[] testInts = { 0, 1, -1, int.MaxValue, int.MinValue };
uint[] testUints = { uint.MinValue, 1, uint.MaxValue / 2, uint.MaxValue };

foreach (var Int in testInts)
    uint asUint = unchecked((uint)Int);
    Console.WriteLine("int....: {0:D10} ({1})", Int, BitConverter.ToString(BitConverter.GetBytes(Int)));
    Console.WriteLine("asUint.: {0:D10} ({1})", asUint, BitConverter.ToString(BitConverter.GetBytes(asUint)));
    Console.WriteLine(new string('-',30));
Console.WriteLine(new string('=', 30));
foreach (var Uint in testUints)
    int asInt = unchecked((int)Uint);
    Console.WriteLine("uint...: {0:D10} ({1})", Uint, BitConverter.ToString(BitConverter.GetBytes(Uint)));
    Console.WriteLine("asInt..: {0:D10} ({1})", asInt, BitConverter.ToString(BitConverter.GetBytes(asInt)));
    Console.WriteLine(new string('-', 30));

Can I access variables from another file?

This is quite an old question, but I'm going to provide a modern solution that's been available since ES6 - export and import:

In first.js:

let colorcodes = <whatever>;
export default colorcodes //or a different export statement

In second.js:

import colorcodes from <path-to-first.js> //or a matching import statement

PHPExcel - set cell type before writing a value in it

When the text is a number with leading zeros, then do: (Cuando el texto es un número que empieza por ceros, hacer)

$objPHPExcel->getActiveSheet()->setCellValueExplicit('A1', $val,PHPExcel_Cell_DataType::TYPE_STRING);

How to check if a String contains only ASCII?

try this:

for (char c: string.toCharArray()){
  if (((int)c)>127){
    return false;
return true;

WaitAll vs WhenAll

As an example of the difference -- if you have a task the does something with the UI thread (e.g. a task that represents an animation in a Storyboard) if you Task.WaitAll() then the UI thread is blocked and the UI is never updated. if you use await Task.WhenAll() then the UI thread is not blocked, and the UI will be updated.

Error: EACCES: permission denied, access '/usr/local/lib/node_modules'

Simply you can change the owner or just use sudo before you command like this

sudo chown -R [owner]:[owner] /usr/local/lib/node_modules (change owner)


sudo npm install -g json-server

that's it.

How does C#'s random number generator work?

I've been searching the internet for RNG for a while now. Everything I saw was either TOO complex or was just not what I was looking for. After reading a few articles I was able to come up with this simple code.

  Random rnd = new Random(DateTime.Now.Millisecond);
  int[] b = new int[10] { 5, 8, 1, 7, 3, 2, 9, 0, 4, 6 };
  textBox1.Text = Convert.ToString(b[rnd.Next(10)])

Simple explanation,

  1. create a 1 dimensional integer array.
  2. full up the array with unordered numbers.
  3. use the rnd.Next to get the position of the number that will be picked.

This works well.

To obtain a random number less than 100 use

  Random rnd = new Random(DateTime.Now.Millisecond);
  int[] b = new int[10] { 5, 8, 1, 7, 3, 2, 9, 0, 4, 6 };
  int[] d = new int[10] { 9, 4, 7, 2, 8, 0, 5, 1, 3, 4 };
  textBox1.Text = Convert.ToString(b[rnd.Next(10)]) + Convert.ToString(d[rnd.Next(10)]);

and so on for 3, 4, 5, and 6 ... digit random numbers.

Hope this assists someone positively.

How to test valid UUID/GUID?

If you want to check or validate a specific UUID version, here are the corresponding regexes.

Note that the only difference is the version number, which is explained in 4.1.3. Version chapter of UUID 4122 RFC.

The version number is the first character of the third group : [VERSION_NUMBER][0-9A-F]{3} :

  • UUID v1 :

  • UUID v2 :

  • UUID v3 :

  • UUID v4 :

  • UUID v5 :


Deserialize JSON into C# dynamic object?

There is a lightweight JSON library for C# called SimpleJson.

It supports .NET 3.5+, Silverlight and Windows Phone 7.

It supports dynamic for .NET 4.0

It can also be installed as a NuGet package

Install-Package SimpleJson

adb is not recognized as internal or external command on windows

You have two ways:

First go to the particular path of Android SDK:

1) Open your command prompt and traverse to the platform-tools directory through it such as

$ cd Frameworks\Android-Sdk\platform-tools

2) Run your adb commands now such as to know that your adb is working properly :

$ adb devices OR adb logcat OR simply adb

Second way is :

1) Right click on your My Computer.

2) Open Environment variables.

3) Add new variable to your System PATH variable(Add if not exist otherwise no need to add new variable if already exist).

4) Add path of platform-tools directory to as value of this variable such as C:\Program Files\android-sdk\platform-tools.

5) Restart your computer once.

6) Now run the above adb commands such adb devices or other adb commands from anywhere in command prompt.

Also on you can fire a command on terminal setx PATH "%PATH%;C:\Program Files\android-sdk\platform-tools"

C# Break out of foreach loop after X number of items

This should work.

int i = 1;
foreach (ListViewItem lvi in listView.Items) {
    if(++i == 50) break;

APT command line interface-like yes/no input?

I'd do it this way:

# raw_input returns the empty string for "enter"
yes = {'yes','y', 'ye', ''}
no = {'no','n'}

choice = raw_input().lower()
if choice in yes:
   return True
elif choice in no:
   return False
   sys.stdout.write("Please respond with 'yes' or 'no'")

unable to remove file that really exists - fatal: pathspec ... did not match any files

Your file .idea/workspace.xml is not under git version control. You have either not added it yet (check git status/Untracked files) or ignored it (using .gitignore or .git/info/exclude files)

You can verify it using following git command, that lists all ignored files:

git ls-files --others -i --exclude-standard

Remove values from select list based on condition

    var select = document.getElementsByName('val')[0];

RelativeLayout center vertical

This is working for me.

<RelativeLayout xmlns:android=""
    android:background="#096d74" > 

    android:contentDescription="@null" />


How can I get a list of all functions stored in the database of a particular schema in PostgreSQL?

\df <schema>.*

in psql gives the necessary information.

To see the query that's used internally connect to a database with psql and supply an extra "-E" (or "--echo-hidden") option and then execute the above command.

How can I debug javascript on Android?

No one mentioned liriliri/eruda which adds its own debugging tools meant for mobile websites/apps

Adding this to your page:

<script src="//"></script>

Will add a floating icon to your page which opens the console.

How do you round a number to two decimal places in C#?

string a = "10.65678";

decimal d = Math.Round(Convert.ToDouble(a.ToString()),2)

Converting a string to a date in JavaScript

Yet another way to do it:

String.prototype.toDate = function(format) {
    format = format || "dmy";
    var separator = this.match(/[^0-9]/)[0];
    var components = this.split(separator);
    var day, month, year;
    for (var key in format) {
        var fmt_value = format[key];
        var value = components[key];
        switch (fmt_value) {
            case "d":
                day = parseInt(value);
            case "m":
                month = parseInt(value)-1;
            case "y":
                year = parseInt(value);
    return new Date(year, month, day);
a = "3/2/2017";
// Date 2017-02-03T00:00:00.000Z

How to display a Windows Form in full screen on top of the taskbar?

I've tried so many solutions, some of them works on Windows XP and all of them did NOT work on Windows 7. After all I write a simple method to do so.

private void GoFullscreen(bool fullscreen)
        if (fullscreen)
            this.WindowState = FormWindowState.Normal;
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
            this.Bounds = Screen.PrimaryScreen.Bounds;
            this.WindowState = FormWindowState.Maximized;
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.Sizable;

the order of code is important and will not work if you change the place of WindwosState and FormBorderStyle.

One of the advantages of this method is leaving the TOPMOST on false that allow other forms to come over the main form.

It absolutely solved my problem.

How do I delete NuGet packages that are not referenced by any project in my solution?

If you want to delete/uninstall Nuget package which is applied to multiple projects in your solutions then go to:

  1. Tools-> Nuget Package Manager -> Manage Nuget Packages for Solution

  2. In the left column where is 'Installed packages' select 'All', so you'll see a list of installed packages and Manage button across them.

  3. Select Manage button and you'll get a pop out, deselect the checkbox across project name and Ok it

The rest of the work Package Manager will do it for you.

Warning comparison between pointer and integer

This: "\0" is a string, not a character. A character uses single quotes, like '\0'.

Passing an array by reference in C?

In C arrays are passed as a pointer to the first element. They are the only element that is not really passed by value (the pointer is passed by value, but the array is not copied). That allows the called function to modify the contents.

void reset( int *array, int size) {
   memset(array,0,size * sizeof(*array));
int main()
   int array[10];
   reset( array, 10 ); // sets all elements to 0

Now, if what you want is changing the array itself (number of elements...) you cannot do it with stack or global arrays, only with dynamically allocated memory in the heap. In that case, if you want to change the pointer you must pass a pointer to it:

void resize( int **p, int size ) {
   free( *p );
   *p = malloc( size * sizeof(int) );
int main() {
   int *p = malloc( 10 * sizeof(int) );
   resize( &p, 20 );

In the question edit you ask specifically about passing an array of structs. You have two solutions there: declare a typedef, or make explicit that you are passing an struct:

struct Coordinate {
   int x;
   int y;
void f( struct Coordinate coordinates[], int size );
typedef struct Coordinate Coordinate;  // generate a type alias 'Coordinate' that is equivalent to struct Coordinate
void g( Coordinate coordinates[], int size ); // uses typedef'ed Coordinate

You can typedef the type as you declare it (and it is a common idiom in C):

typedef struct Coordinate {
   int x;
   int y;
} Coordinate;

How do I work with a git repository within another repository?

The key is git submodules.

Start reading the Submodules chapter of the Git Community Book or of the Users Manual

Say you have repository PROJECT1, PROJECT2, and MEDIA...

cd /path/to/PROJECT1
git submodule add ssh://
git commit -m "Added Media submodule"

Repeat on the other repo...

Now, the cool thing is, that any time you commit changes to MEDIA, you can do this:

cd /path/to/PROJECT2/MEDIA
git pull
cd ..
git add MEDIA
git commit -m "Upgraded media to version XYZ"

This just recorded the fact that the MEDIA submodule WITHIN PROJECT2 is now at version XYZ.

It gives you 100% control over what version of MEDIA each project uses. git submodules are great, but you need to experiment and learn about them.

With great power comes the great chance to get bitten in the rump.

Detecting value change of input[type=text] in jQuery

you can also use textbox events -

<input id="txt1" type="text" onchange="SetDefault($(this).val());" onkeyup="this.onchange();" onpaste="this.onchange();" oninput="this.onchange();">

function SetDefault(Text){

Try This

How do you display a Toast from a background thread on Android?

You can do it by calling an Activity's runOnUiThread method from your thread:

activity.runOnUiThread(new Runnable() {
    public void run() {
        Toast.makeText(activity, "Hello", Toast.LENGTH_SHORT).show();

How to get AIC from Conway–Maxwell-Poisson regression via COM-poisson package in R?

I figured out myself.

cmp calls ComputeBetasAndNuHat which returns a list which has objective as minusloglik

So I can change the function cmp to get this value.

Oracle sqlldr TRAILING NULLCOLS required, but why?

Last column in your input file must have some data in it (be it space or char, but not null). I guess, 1st record contains null after last ',' which sqlldr won't recognize unless specifically asked to recognize nulls using TRAILING NULLCOLS option. Alternatively, if you don't want to use TRAILING NULLCOLS, you will have to take care of those NULLs before you pass the file to sqlldr. Hope this helps

Kotlin: How to get and set a text to TextView in Android using Kotlin?


class Mainactivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {

        txt.setText("hello Kotlin")



Using Django time/date widgets in custom form

The growing complexity of this answer over time, and the many hacks required, probably ought to caution you against doing this at all. It's relying on undocumented internal implementation details of the admin, is likely to break again in future versions of Django, and is no easier to implement than just finding another JS calendar widget and using that.

That said, here's what you have to do if you're determined to make this work:

  1. Define your own ModelForm subclass for your model (best to put it in in your app), and tell it to use the AdminDateWidget / AdminTimeWidget / AdminSplitDateTime (replace 'mydate' etc with the proper field names from your model):

    from django import forms
    from my_app.models import Product
    from django.contrib.admin import widgets                                       
    class ProductForm(forms.ModelForm):
        class Meta:
            model = Product
        def __init__(self, *args, **kwargs):
            super(ProductForm, self).__init__(*args, **kwargs)
            self.fields['mydate'].widget = widgets.AdminDateWidget()
            self.fields['mytime'].widget = widgets.AdminTimeWidget()
            self.fields['mydatetime'].widget = widgets.AdminSplitDateTime()
  2. Change your URLconf to pass 'form_class': ProductForm instead of 'model': Product to the generic create_object view (that'll mean "from my_app.forms import ProductForm" instead of "from my_app.models import Product", of course).

  3. In the head of your template, include {{ }} to output the links to the Javascript files.

  4. And the hacky part: the admin date/time widgets presume that the i18n JS stuff has been loaded, and also require core.js, but don't provide either one automatically. So in your template above {{ }} you'll need:

    <script type="text/javascript" src="/my_admin/jsi18n/"></script>
    <script type="text/javascript" src="/media/admin/js/core.js"></script>

    You may also wish to use the following admin CSS (thanks Alex for mentioning this):

    <link rel="stylesheet" type="text/css" href="/media/admin/css/forms.css"/>
    <link rel="stylesheet" type="text/css" href="/media/admin/css/base.css"/>
    <link rel="stylesheet" type="text/css" href="/media/admin/css/global.css"/>
    <link rel="stylesheet" type="text/css" href="/media/admin/css/widgets.css"/>

This implies that Django's admin media (ADMIN_MEDIA_PREFIX) is at /media/admin/ - you can change that for your setup. Ideally you'd use a context processor to pass this values to your template instead of hardcoding it, but that's beyond the scope of this question.

This also requires that the URL /my_admin/jsi18n/ be manually wired up to the django.views.i18n.javascript_catalog view (or null_javascript_catalog if you aren't using I18N). You have to do this yourself instead of going through the admin application so it's accessible regardless of whether you're logged into the admin (thanks Jeremy for pointing this out). Sample code for your URLconf:

(r'^my_admin/jsi18n', 'django.views.i18n.javascript_catalog'),

Lastly, if you are using Django 1.2 or later, you need some additional code in your template to help the widgets find their media:

{% load adminmedia %} /* At the top of the template. */

/* In the head section of the template. */
<script type="text/javascript">
window.__admin_media_prefix__ = "{% filter escapejs %}{% admin_media_prefix %}{% endfilter %}";

Thanks lupefiasco for this addition.

Pandas: how to change all the values of a column?

You can do a column transformation by using apply

Define a clean function to remove the dollar and commas and convert your data to float.

def clean(x):
    x = x.replace("$", "").replace(",", "").replace(" ", "")
    return float(x)

Next, call it on your column like this.

data['Revenue'] = data['Revenue'].apply(clean)

Removing MySQL 5.7 Completely

You need to remove the /var/lib/mysql folder. Also, purge when you remove the packages (I'm told this helps).

sudo apt-get remove --purge mysql-server mysql-client mysql-common

sudo rm -rf /var/lib/mysql

I was encountering similar issues. The second line got rid of my issues and allowed me to set up MySql from scratch. Hopefully it helps you too!

How can I use custom fonts on a website?

Yes, there is a way. Its called custom fonts in CSS.Your CSS needs to be modified, and you need to upload those fonts to your website.

The CSS required for this is:

@font-face {
     font-family: Thonburi-Bold;
     src: url('pathway/Thonburi-Bold.otf'); 

Convert String To date in PHP

Simple exploding should do the trick:

$monthNamesToInt = array('Jan'=>1,'Feb'=>2, 'Mar'=>3 /*, [...]*/ );
$datetime = '05/Feb/2010:14:00:01';
list($date,$hour,$minute,$second) = explode(':',$datetime);
list($day,$month,$year) = explode('/',$date);

$unixtime = mktime((int)$hour, (int)$minute, (int)$second, $monthNamesToInt[$month], (int)$day, (int)$year);

Android: failed to convert @drawable/picture into a drawable

file name must contain only 012...789 _ . in Resources folder.

for ex:

my-image.png is False!
MyImage.png is False!
my image.png is False!

my-xml.xml is False!
MyXml.xml is False!
my xml.xml is False!

Nuget connection attempt failed "Unable to load the service index for source"

I was trying to add an Azure Artifacts NuGet source.

I followed Microsoft's instructions here, with one critical oversight.

I forgot to replace /v3/index.json with /v2.

enter image description here

NumPy array initialization (fill with identical values)

Apparently, not only the absolute speeds but also the speed order (as reported by user1579844) are machine dependent; here's what I found:

a=np.empty(1e4); a.fill(5) is fastest;

In descending speed order:

timeit a=np.empty(1e4); a.fill(5) 
# 100000 loops, best of 3: 10.2 us per loop
timeit a=np.empty(1e4); a[:]=5
# 100000 loops, best of 3: 16.9 us per loop
timeit a=np.ones(1e4)*5
# 100000 loops, best of 3: 32.2 us per loop
timeit a=np.tile(5,[1e4])
# 10000 loops, best of 3: 90.9 us per loop
timeit a=np.repeat(5,(1e4))
# 10000 loops, best of 3: 98.3 us per loop
timeit a=np.array([5]*int(1e4))
# 1000 loops, best of 3: 1.69 ms per loop (slowest BY FAR!)

So, try and find out, and use what's fastest on your platform.

In Java, what is the best way to determine the size of an object?

I accidentally found a java class "", already in jdk, which is easy to use and seems quite useful for determining the size of an object.

System.out.println(ObjectSizeCalculator.getObjectSize(new<String>(12000, 0.6f, -1)));
System.out.println(ObjectSizeCalculator.getObjectSize(new HashMap<String, Integer>(100000)));
System.out.println(ObjectSizeCalculator.getObjectSize(new int[]{1, 2, 3, 4, 5, 6, 7 }));
System.out.println(ObjectSizeCalculator.getObjectSize(new int[100]));



Spring Boot - How to get the running port

Please make sure you have imported the correct package

import org.springframework.core.env.Environment;

and then use the Environment object

private Environment env;    // Environment Object containts the port number

  public String status()
   return "it is runing on"+(env.getProperty("local.server.port"));

Javascript Array of Functions

Ah man there are so many weird answers...

const execute = (fn) => fn()
const arrayOfFunctions = [fn1, fn2, fn3]

const results =

or if you want to sequentially feed each functions result to the next:
compose(fn3, fn2, fn1)

compose is not supported by default, but there are libraries like ramda, lodash, or even redux which provide this tool

Benefits of using the conditional ?: (ternary) operator

The ternary operator can be included within an rvalue, whereas an if-then-else cannot; on the other hand, an if-then-else can execute loops and other statements, whereas the ternary operator can only execute (possibly void) rvalues.

On a related note, the && and || operators allow some execution patterns which are harder to implement with if-then-else. For example, if one has several functions to call and wishes to execute a piece of code if any of them fail, it can be done nicely using the && operator. Doing it without that operator will either require redundant code, a goto, or an extra flag variable.

How to set opacity to the background color of a div?

I think this covers just about all of the browsers. I have used it successfully in the past.

#div {
    filter: alpha(opacity=50); /* internet explorer */
    -khtml-opacity: 0.5;      /* khtml, old safari */
    -moz-opacity: 0.5;       /* mozilla, netscape */
    opacity: 0.5;           /* fx, safari, opera */

How to force page refreshes or reloads in jQuery?

You don't need jQuery to do this. Embrace the power of JavaScript.


Printing without newline (print 'a',) prints a space, how to remove?

this is really simple

for python 3+ versions you only have to write the following codes

for i in range(20):

just convert the loop to the following codes, you don't have to worry about other things

How do I connect to a terminal to a serial-to-USB device on Ubuntu 10.10 (Maverick Meerkat)?

First check with dmesg | grep tty if system recognize your adapter. Then try to run minicom with sudo minicom -s, go to "Serial port setup" and change the first line to /dev/ttyUSB0.

Don't forget to save config as default with "Save setup as dfl". It works for me on Ubuntu 11.04 on VirtualBox.

Difference between float and decimal data type

decimal is for fixed quantities like money where you want a specific number of decimal places. Floats are for storing ... floating point precision numbers.

What is the correct target for the JAVA_HOME environment variable for a Linux OpenJDK Debian-based distribution?

My correct target has always been to download it from Sun and just install it that way. Then you know exactly what directory everything goes in.

But if you'd prefer to stick with the odd way that Debian installs it, my best guess would be the parent directory just above where the java and javac binaries are located.

(since when you specify it in your path it's $JAVA_HOME/bin) (So in your case it would be ... $JAVA_HOME/share and $JAVA_HOME would be /usr ?)

Eh, that doesn't sound right...

I'm interested to hear the answer to this too!

Android Service Stops When App Is Closed

I'm in the same situation, so far I learned when the app is closed the service get closed also because they are in a one thread, so the service should be on another thread in order fot it not to be closed, look into that and look into keeping the service alive with alarm manager here an example this way your service won't be shown in notification.

lastly, after all the research I've done I'm coming to realize that the best choice for a long running service is startForeground(), because it is made for that and the system actually deals with your service well.

How can I view the shared preferences file using Android Studio?

Another simple way would be using a root explorer app on your phone.

Then go to /data/data/package name/shared preferences folder/name of your preferences.xml, you can use ES File explorer, and go to the root of your device, not sd card.

Difference between PCDATA and CDATA in DTD

PCDATA – parsed character data. It parses all the data in an XML document.



Here, the <family> element contains 2 more elements: <mother> and <father>. So it parses further to get the text of mother and father to give the text value of family as “mom dad”

CDATA – unparsed character Data. This is the data that should not be parsed further in an xml document.


Here, the text value of family will be <mother>mom</mother><father>dad</father>.

PHP Fatal error: Uncaught exception 'Exception'

Just adding a bit of extra information here in case someone has the same issue as me.

I use namespaces in my code and I had a class with a function that throws an Exception.

However my try/catch code in another class file was completely ignored and the normal PHP error for an uncatched exception was thrown.

Turned out I forgot to add "use \Exception;" at the top, adding that solved the error.

How to add multiple font files for the same font?

The solution seems to be to add multiple @font-face rules, for example:

@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans.ttf");
@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans-Bold.ttf");
    font-weight: bold;
@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans-Oblique.ttf");
    font-style: italic, oblique;
@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans-BoldOblique.ttf");
    font-weight: bold;
    font-style: italic, oblique;

By the way, it would seem Google Chrome doesn't know about the format("ttf") argument, so you might want to skip that.

(This answer was correct for the CSS 2 specification. CSS3 only allows for one font-style rather than a comma-separated list.)

Dropping connected users in Oracle database

Sometimes Oracle drop user takes long time to execute. In that case user might be connected to the database. Better you can kill user session and drop the user.

SQL> select 'alter system kill session ''' || sid || ',' || serial# || ''' immediate;' from v$session where username ='&USERNAME';


Ignore case in Python strings

I can't find any other built-in way of doing case-insensitive comparison: The python cook-book recipe uses lower().

However you have to be careful when using lower for comparisons because of the Turkish I problem. Unfortunately Python's handling for Turkish Is is not good. i is converted to I, but I is not converted to i. I is converted to i, but i is not converted to I.

Create a pointer to two-dimensional array

In C99 (supported by clang and gcc) there's an obscure syntax for passing multi-dimensional arrays to functions by reference:

int l_matrix[10][20];

void test(int matrix_ptr[static 10][20]) {

int main(void) {

Unlike a plain pointer, this hints about array size, theoretically allowing compiler to warn about passing too-small array and spot obvious out of bounds access.

Sadly, it doesn't fix sizeof() and compilers don't seem to use that information yet, so it remains a curiosity.

Dialogs / AlertDialogs: How to "block execution" while dialog is up (.NET-style)

In Android, the structure is different from .NET:

AlertDialog.Builder builder = new AlertDialog.Builder(this);
       .setPositiveButton("Ok", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int id) {
               // Handle Ok
       .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int id) {
               // Handle Cancel

Will get you a dialog with two buttons and you handle the button clicks with callbacks. You might be able to write some code to make the syntax more closely resemble .NET, but the dialog lifecycle is pretty intertwined with Activity, so in the end, it might be more trouble than it's worth. Additional dialog references are here.

how to set the query timeout from SQL connection string

No. It's per command, not per connection.

Edit, May 2013

As requested in comment:

Some more notes about commands and execution time outs in SQL Server (DBA.SE). And more SO stuff: What happens to an uncommitted transaction when the connection is closed?

How can I switch word wrap on and off in Visual Studio Code?

Here you go with word-wrap on Visual Studio Code.

Mockito How to mock and assert a thrown exception?

If you want to test the exception message as well you can use JUnit's ExpectedException with Mockito:

public ExpectedException expectedException = ExpectedException.none();

public void testExceptionMessage() throws Exception {
    expectedException.expectMessage("The expected message");

    given( AnyException("The expected message"));

Causes of getting a java.lang.VerifyError

write on file:


into dependencies next: <module name="sun.jdk"/>

Created Button Click Event c#

Create the Button and add it to Form.Controls list to display it on your form:

Button buttonOk = new Button();
buttonOk.Location = new Point(295, 45);  //or what ever position you want it to give
buttonOk.Text = "OK"; //or what ever you want to write over it
buttonOk.Click += new EventHandler(buttonOk_Click);
this.Controls.Add(buttonOk); //here you add it to the Form's Controls list

Create the button click method here:

void buttonOk_Click(object sender, EventArgs e)
            this.Close(); //all your choice to close it or remove this line

Set new id with jQuery

Did you try


instead of

$(this).attr('value', 'test');

val() is generally easier, since the attribute you need to change may be different on different DOM elements.

Group by with union mysql select query

This may be what your after:

SELECT Count(Owner_ID), Name
    SELECT M.Owner_ID, O.Name, T.Type
    FROM Transport As T, Owner As O, Motorbike As M
    WHERE T.Type = 'Motorbike'
    AND O.Owner_ID = M.Owner_ID
    AND T.Type_ID = M.Motorbike_ID


    SELECT C.Owner_ID, O.Name, T.Type
    FROM Transport As T, Owner As O, Car As C
    WHERE T.Type = 'Car'
    AND O.Owner_ID = C.Owner_ID
    AND T.Type_ID = C.Car_ID

How to speed up insertion performance in PostgreSQL

I encountered this insertion performance problem as well. My solution is spawn some go routines to finish the insertion work. In the meantime, SetMaxOpenConns should be given a proper number otherwise too many open connection error would be alerted.

db, _ := 
var wg sync.WaitGroup
for _, query := range queries {
    go func(msg string) {
        defer wg.Done()
        _, err := db.Exec(msg)
        if err != nil {

The loading speed is much faster for my project. This code snippet just gave an idea how it works. Readers should be able to modify it easily.

Delete last N characters from field in a SQL Server database

This should do it, removing characters from the left by one or however many needed.

lEFT(columnX,LEN(columnX) - 1) AS NewColumnName

Cannot resolve the collation conflict between "SQL_Latin1_General_CP1_CI_AS" and "Latin1_General_CI_AS" in the equal to operation

You may not have any collation issues in your database whatsoever, but if you restored a copy of your database from a backup on a server with a different collation than the origin, and your code is creating temporary tables, those temporary tables would inherit collation from the server and there would be conflicts with your database.

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

Not pretty. Definitely not pretty:

ls $Env:windir\Microsoft.NET\Framework | ? { $_.PSIsContainer } | select -exp Name -l 1

This may or may not work. But as far as the latest version is concerned this should be pretty reliable, as there are essentially empty folders for old versions (1.0, 1.1) but not newer ones – those only appear once the appropriate framework is installed.

Still, I suspect there must be a better way.