Programs & Examples On #Cellid

A Cell ID (CID) is a generally unique number used to identify each Base transceiver station (BTS) or sector of a BTS within a Location area code (LAC) if not within a GSM network.

UICollectionView - dynamic cell height?

Here is a Ray Wenderlich tutorial that shows you how to use AutoLayout to dynamically size UITableViewCells. I would think it would be the same for UICollectionViewCell.

Basically, though, you end up dequeueing and configuring a prototype cell and grabbing its height. After reading this article, I decided to NOT implement this method and just write some clear, explicit sizing code.

Here's what I consider the "secret sauce" for the entire article:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    return [self heightForBasicCellAtIndexPath:indexPath];

- (CGFloat)heightForBasicCellAtIndexPath:(NSIndexPath *)indexPath {
    static RWBasicCell *sizingCell = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sizingCell = [self.tableView dequeueReusableCellWithIdentifier:RWBasicCellIdentifier];

    [self configureBasicCell:sizingCell atIndexPath:indexPath];
    return [self calculateHeightForConfiguredSizingCell:sizingCell];

- (CGFloat)calculateHeightForConfiguredSizingCell:(UITableViewCell *)sizingCell {
    [sizingCell setNeedsLayout];
    [sizingCell layoutIfNeeded];

    CGSize size = [sizingCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    return size.height + 1.0f; // Add 1.0f for the cell separator height

EDIT: I did some research into your crash and decided that there is no way to get this done without a custom XIB. While that is a bit frustrating, you should be able to cut and paste from your Storyboard to a custom, empty XIB.

Once you've done that, code like the following will get you going:

//  ViewController.m
#import "ViewController.h"
#import "CollectionViewCell.h"
@interface ViewController () <UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout> {

@property (weak, nonatomic) IBOutlet CollectionViewCell *cell;
@property (weak, nonatomic) IBOutlet UICollectionView   *collectionView;
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor lightGrayColor];
    [self.collectionView registerNib:[UINib nibWithNibName:@"CollectionViewCell" bundle:nil] forCellWithReuseIdentifier:@"cell"];
- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
    return 1;
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return 50;
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
    return 10.0f;
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
    return 10.0f;
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    return [self sizingForRowAtIndexPath:indexPath];
- (CGSize)sizingForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *title                  = @"This is a long title that will cause some wrapping to occur. This is a long title that will cause some wrapping to occur.";
    static NSString *subtitle               = @"This is a long subtitle that will cause some wrapping to occur. This is a long subtitle that will cause some wrapping to occur.";
    static NSString *buttonTitle            = @"This is a really long button title that will cause some wrapping to occur.";
    static CollectionViewCell *sizingCell   = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sizingCell                          = [[NSBundle mainBundle] loadNibNamed:@"CollectionViewCell" owner:self options:nil][0];
    [sizingCell configureWithTitle:title subtitle:[NSString stringWithFormat:@"%@: Number %d.", subtitle, (int)indexPath.row] buttonTitle:buttonTitle];
    [sizingCell setNeedsLayout];
    [sizingCell layoutIfNeeded];
    CGSize cellSize = [sizingCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    NSLog(@"cellSize: %@", NSStringFromCGSize(cellSize));
    return cellSize;
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *title                  = @"This is a long title that will cause some wrapping to occur. This is a long title that will cause some wrapping to occur.";
    static NSString *subtitle               = @"This is a long subtitle that will cause some wrapping to occur. This is a long subtitle that will cause some wrapping to occur.";
    static NSString *buttonTitle            = @"This is a really long button title that will cause some wrapping to occur.";
    CollectionViewCell *cell                = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
    [cell configureWithTitle:title subtitle:[NSString stringWithFormat:@"%@: Number %d.", subtitle, (int)indexPath.row] buttonTitle:buttonTitle];
    return cell;

The code above (along with a very basic UICollectionViewCell subclass and associated XIB) gives me this:

enter image description here

How to Correctly handle Weak Self in Swift Blocks with Arguments

**EDITED for Swift 4.2:

As @Koen commented, swift 4.2 allows:

guard let self = self else {
   return // Could not get a strong reference for self :`(

// Now self is a strong reference

P.S.: Since I am having some up-votes, I would like to recommend the reading about escaping closures.

EDITED: As @tim-vermeulen has commented, Chris Lattner said on Fri Jan 22 19:51:29 CST 2016, this trick should not be used on self, so please don't use it. Check the non escaping closures info and the capture list answer from @gbk.**

For those who use [weak self] in capture list, note that self could be nil, so the first thing I do is check that with a guard statement

guard let `self` = self else {

If you are wondering what the quote marks are around self is a pro trick to use self inside the closure without needing to change the name to this, weakSelf or whatever.

UICollectionView current visible cell index

For completeness sake, this is the method that ended up working for me. It was a combination of @Anthony & @iAn's methods.

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
      CGRect visibleRect = (CGRect){.origin = self.collectionView.contentOffset, .size = self.collectionView.bounds.size};
      CGPoint visiblePoint = CGPointMake(CGRectGetMidX(visibleRect), CGRectGetMidY(visibleRect));
      NSIndexPath *visibleIndexPath = [self.collectionView indexPathForItemAtPoint:visiblePoint];

UITableView with fixed section headers

You can also set the tableview's bounces property to NO. This will keep the section headers non-floating/static, but then you also lose the bounce property of the tableview.

Creating a UITableView Programmatically

#import "ViewController.h"

@interface ViewController ()


    NSMutableArray *name;



- (void)viewDidLoad 


    [super viewDidLoad];
    name=[[NSMutableArray alloc]init];
    [name addObject:@"ronak"];
    [name addObject:@"vibha"];
    [name addObject:@"shivani"];
    [name addObject:@"nidhi"];
    [name addObject:@"firdosh"];
    [name addObject:@"himani"];

    _tableview_outlet.delegate = self;
    _tableview_outlet.dataSource = self;


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section


return [name count];


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath


    static NSString *simpleTableIdentifier = @"cell";

    UITableViewCell *cell = [tableView       dequeueReusableCellWithIdentifier:simpleTableIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];

    cell.textLabel.text = [name objectAtIndex:indexPath.row];
    return cell;

Assertion failure in dequeueReusableCellWithIdentifier:forIndexPath:

Make sure that the CellIdentifier == identifier of the cell in a storyboard, both names are same. Hope this works for u

Xcode error - Thread 1: signal SIGABRT

SIGABRT is, as stated in other answers, a general uncaught exception. You should definitely learn a little bit more about Objective-C. The problem is probably in your UITableViewDelegate method didSelectRowAtIndexPath.

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

I can't tell you much more until you show us something of the code where you handle the table data source and delegate methods.

How do you load custom UITableViewCells from Xib files?

If you're using Interface Builder to make cells, check that you've set the Identifier in the Inspector. Then check that it's the same when calling dequeueReusableCellWithIdentifier.

I accidentally forgot to set some identifiers in a table-heavy project, and the performance change was like night and day.

Line break in SSRS expression

I've always had luck with the Chr(10) & Chr(13) - I have provided a sample below. This is an expression for an address text box I have in a report.

=Iif(Fields!GUAR_STREET_2.Value <> "",Fields!GUAR_STREET.Value & Chr(10) & Chr(13) & LTrim(Fields!GUAR_STREET_2.Value),Fields!GUAR_STREET.Value)

Also, if you are building a string you need to concatenate stuff together with an & not a + Here is what I think your example should look like

    =IIF(First(Fields!VCHTYPE.Value, "Dataset1")="C","This is a huge paragrpah of text." &
Chr(10) & Chr(13) & "separated by line feeds at each paragraph." &
Chr(10) & Chr(13) & Chr(10) & Chr(13) & "I want to separate the paragraphs." &
Chr(10) & Chr(13) &  Chr(10) & Chr(13) & "Its not working though."
, "This is the second huge paragraph of text." &
Chr(10) & Chr(13) & "separated by line feeds at each paragraph." &
Chr(10) & Chr(13) & Chr(10) & Chr(13) & "I want to separate the paragraphs." &
Chr(10) & Chr(13) & Chr(10) & Chr(13) & "Its not working though." )

Inserting line breaks into PDF

$pdf->MultiCell($height,$width,"Line1 \nLine2 \nLine3",1,'C',1);

In every Column, before you set the X Position indicate first the Y position, so it became like this

Column 1

$pdf->MultiCell($height,$width,"Line1 \nLine2 \nLine3",1,'C',1);

Column 2

$pdf->MultiCell($height,$width,"Line1 \nLine2 \nLine3",1,'C',1);

How to declare a variable in MySQL?

There are mainly three types of variables in MySQL:

  1. User-defined variables (prefixed with @):

    You can access any user-defined variable without declaring it or initializing it. If you refer to a variable that has not been initialized, it has a value of NULL and a type of string.

    SELECT @var_any_var_name

    You can initialize a variable using SET or SELECT statement:

    SET @start = 1, @finish = 10;    


    SELECT @start := 1, @finish := 10;
    SELECT * FROM places WHERE place BETWEEN @start AND @finish;

    User variables can be assigned a value from a limited set of data types: integer, decimal, floating-point, binary or nonbinary string, or NULL value.

    User-defined variables are session-specific. That is, a user variable defined by one client cannot be seen or used by other clients.

    They can be used in SELECT queries using Advanced MySQL user variable techniques.

  2. Local Variables (no prefix) :

    Local variables needs to be declared using DECLARE before accessing it.

    They can be used as local variables and the input parameters inside a stored procedure:

    CREATE PROCEDURE sp_test(var1 INT) 
        DECLARE start  INT unsigned DEFAULT 1;  
        DECLARE finish INT unsigned DEFAULT 10;
        SELECT  var1, start, finish;
        SELECT * FROM places WHERE place BETWEEN start AND finish; 
    END; //
    CALL sp_test(5);

    If the DEFAULT clause is missing, the initial value is NULL.

    The scope of a local variable is the BEGIN ... END block within which it is declared.

  3. Server System Variables (prefixed with @@):

    The MySQL server maintains many system variables configured to a default value. They can be of type GLOBAL, SESSION or BOTH.

    Global variables affect the overall operation of the server whereas session variables affect its operation for individual client connections.

    To see the current values used by a running server, use the SHOW VARIABLES statement or SELECT @@var_name.

    SHOW VARIABLES LIKE '%wait_timeout%';
    SELECT @@sort_buffer_size;

    They can be set at server startup using options on the command line or in an option file. Most of them can be changed dynamically while the server is running using SET GLOBAL or SET SESSION:

    -- Syntax to Set value to a Global variable:
    SET GLOBAL sort_buffer_size=1000000;
    SET @@global.sort_buffer_size=1000000;
    -- Syntax to Set value to a Session variable:
    SET sort_buffer_size=1000000;
    SET SESSION sort_buffer_size=1000000;
    SET @@sort_buffer_size=1000000;
    SET @@local.sort_buffer_size=10000;

Node.js/Windows error: ENOENT, stat 'C:\Users\RT\AppData\Roaming\npm'

This can also be fixed by installing a node package manually.

npm install npm -g

The process of doing that will setup all the required directories.

How to change indentation mode in Atom?

If global tab/spaces indentation settings no longer fit your needs (I.E. you find yourself working with legacy codebases with varied indentation formats, and you need to quickly switch between them, and the auto-detect isn't working) you might try the tab-control plugin, which sort of duplicates the functionality of the menu in your screenshot.

How can I display an RTSP video stream in a web page?

Also you can try opensource WebRTC Media Server Kurento

Which can play RTSP video stream and send it to WebRTC or transcode to RTMP or saving on server.

We are useing it on Production for the following cases:

 - WebRTC to Webrtc (many to many)
 - WebRTC to RTMP
 - RTSP to WebRTC

Popup window in winform c#

"But the thing is I also want to be able to add textboxes etc in this popup window thru the form designer."

It's unclear from your description at what stage in the development process you're in. If you haven't already figured it out, to create a new Form you click on Project --> Add Windows Form, then type in a name for the form and hit the "Add" button. Now you can add controls to your form as you'd expect.

When it comes time to display it, follow the advice of the other posts to create an instance and call Show() or ShowDialog() as appropriate.

Git push: "fatal 'origin' does not appear to be a git repository - fatal Could not read from remote repository."

This is the way I updated the master branch

This kind of error occurs commonly after deleting the initial code on your project

So, go ahead, first of all, verify the actual remote version, then remove the origin add the comment, and copy the repo URL into the project files.

$ git remote -v
$ git remote rm origin
$ git commit -m "your commit"
$ git remote add origin
$ git push -f origin master

'Syntax Error: invalid syntax' for no apparent reason

I noticed that invalid syntax error for no apparent reason can be caused by using space in:

print(f'{something something}')

Python IDLE seems to jump and highlight a part of the first line for some reason (even if the first line happens to be a comment), which is misleading.

What ports does RabbitMQ use?

Port Access

Firewalls and other security tools may prevent RabbitMQ from binding to a port. When that happens, RabbitMQ will fail to start. Make sure the following ports can be opened:

4369: epmd, a peer discovery service used by RabbitMQ nodes and CLI tools

5672, 5671: used by AMQP 0-9-1 and 1.0 clients without and with TLS

25672: used by Erlang distribution for inter-node and CLI tools communication and is allocated from a dynamic range (limited to a single port by default, computed as AMQP port + 20000). See networking guide for details.

15672: HTTP API clients and rabbitmqadmin (only if the management plugin is enabled)

61613, 61614: STOMP clients without and with TLS (only if the STOMP plugin is enabled)

1883, 8883: (MQTT clients without and with TLS, if the MQTT plugin is enabled

15674: STOMP-over-WebSockets clients (only if the Web STOMP plugin is enabled)

15675: MQTT-over-WebSockets clients (only if the Web MQTT plugin is enabled)

Reference doc:

CSS3 opacity gradient?

Except using css mask answered by @vals, you can also use transparency gradient background and set background-clip to text.

Create proper gradient:

background: linear-gradient(to bottom, rgba(0, 0, 0, 1) 0%, rgba(0, 0, 0, 0) 100%);

Then clip the backgroud with text:

background-clip: text;
color: transparent;


Tested under Chrome 75 under Windows 10.

Supported platforms:

How do you get the current text contents of a QComboBox?

You can convert the QString type to python string by just using the str function. Assuming you are not using any Unicode characters you can get a python string as below:

text = str(combobox1.currentText())

If you are using any unicode characters, you can do:

text = unicode(combobox1.currentText())

How to refresh or show immediately in datagridview after inserting?

Only need to fill datagrid again like this:


If you use automaticlly connect from dataGridView this code create automaticlly in Form_Load()

Adding Buttons To Google Sheets and Set value to Cells on clicking

You can insert an image that looks like a button. Then attach a script to the image.

  • INSERT menu
  • Image

Insert Image

You can insert any image. The image can be edited in the spreadsheet

Edit Image

Image of a Button

Image of Button

Assign a function name to an image:

Assign Function

How do you join on the same table, twice, in mysql?

Given the following tables..

Domain Table
dom_id | dom_url

Review Table
rev_id | rev_dom_from | rev_dom_for

Try this sql... (It's pretty much the same thing that Stephen Wrighton wrote above) The trick is that you are basically selecting from the domain table twice in the same query and joining the results.

Select d1.dom_url, d2.dom_id from
review r, domain d1, domain d2
where d1.dom_id = r.rev_dom_from
and d2.dom_id = r.rev_dom_for

If you are still stuck, please be more specific with exactly it is that you don't understand.

How to create JNDI context in Spring Boot with Embedded Tomcat Container

Please note instead of

public TomcatEmbeddedServletContainerFactory tomcatFactory()

I had to use the following method signature

public EmbeddedServletContainerFactory embeddedServletContainerFactory() 

Automatic creation date for Django model form objects?

You can use the auto_now and auto_now_add options for updated_at and created_at respectively.

class MyModel(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

Spring Boot: Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean

Adding the annotation @SpringBootApplication Before the starter class fixed this problem for me (so in essence, this error message can mean "you don't have a @SpringBootApplication marked class anywhere, you need at least one)

public class AppStarter {

    public static void main(String[] args) {, args);

How can javascript upload a blob?

I was able to get @yeeking example to work by not using FormData but using javascript object to transfer the blob. Works with a sound blob created using recorder.js. Tested in Chrome version 32.0.1700.107

function uploadAudio( blob ) {
  var reader = new FileReader();
  reader.onload = function(event){
    var fd = {};
    fd["fname"] = "test.wav";
    fd["data"] =;
      type: 'POST',
      url: 'upload.php',
      data: fd,
      dataType: 'text'
    }).done(function(data) {

Contents of upload.php

// pull the raw binary data from the POST array
$data = substr($_POST['data'], strpos($_POST['data'], ",") + 1);
// decode it
$decodedData = base64_decode($data);
// print out the raw data,
$filename = $_POST['fname'];
echo $filename;
// write the data out to the file
$fp = fopen($filename, 'wb');
fwrite($fp, $decodedData);

When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used?

Use dynamic_cast for converting pointers/references within an inheritance hierarchy.

Use static_cast for ordinary type conversions.

Use reinterpret_cast for low-level reinterpreting of bit patterns. Use with extreme caution.

Use const_cast for casting away const/volatile. Avoid this unless you are stuck using a const-incorrect API.

Use -notlike to filter out multiple strings in PowerShell

In order to support "matches any of ..." scenarios, I created a function that is pretty easy to read. My version has a lot more to it because its a PowerShell 2.0 cmdlet but the version I'm pasting below should work in 1.0 and has no frills.

You call it like so:

Get-Process | Where-Match Company -Like '*VMWare*','*Microsoft*'
Get-Process | Where-Match Company -Regex '^Microsoft.*'

filter Where-Match($Selector,[String[]]$Like,[String[]]$Regex) {

    if ($Selector -is [String]) { $Value = $_.$Selector }
    elseif ($Selector -is [ScriptBlock]) { $Value = &$Selector }
    else { throw 'Selector must be a ScriptBlock or property name' }

    if ($Like.Length) {
        foreach ($Pattern in $Like) {
            if ($Value -like $Pattern) { return $_ }

    if ($Regex.Length) {
        foreach ($Pattern in $Regex) {
            if ($Value -match $Pattern) { return $_ }


filter Where-NotMatch($Selector,[String[]]$Like,[String[]]$Regex) {

    if ($Selector -is [String]) { $Value = $_.$Selector }
    elseif ($Selector -is [ScriptBlock]) { $Value = &$Selector }
    else { throw 'Selector must be a ScriptBlock or property name' }

    if ($Like.Length) {
        foreach ($Pattern in $Like) {
            if ($Value -like $Pattern) { return }

    if ($Regex.Length) {
        foreach ($Pattern in $Regex) {
            if ($Value -match $Pattern) { return }

    return $_


How Do I Make Glyphicons Bigger? (Change Size?)

Fontawesome has a perfect solution to this.

I implemented the same. just on your main .css file add this

.gi-2x{font-size: 2em;}
.gi-3x{font-size: 3em;}
.gi-4x{font-size: 4em;}
.gi-5x{font-size: 5em;}

In your example you just have to do this.

<div class = "jumbotron">
    <span class="glyphicon glyphicon-globe gi-5x"></span>

How to Cast Objects in PHP

You may think about factories

class XyFactory {
    public function createXyObject ($other) {
        $new = new XyObject($other->someValue);
        // Do other things, that let $new look like $other (except the used class)
        return $new;

Otherwise user250120s solution is the only one, which comes close to class casting.

Convert string to int array using LINQ

This post asked a similar question and used LINQ to solve it, maybe it will help you out too.

string s1 = "1;2;3;4;5;6;7;8;9;10;11;12";
int[] ia = s1.Split(';').Select(n => Convert.ToInt32(n)).ToArray();

java.util.Date format SSSSSS: if not microseconds what are the last 3 digits?

Use java.sql.Timestamp.toString if you want to get fractional seconds in text representation. The difference betwen Timestamp from DB and Java Date is that DB precision is nanoseconds while Java Date precision is milliseconds.

How can I fix the form size in a C# Windows Forms application and not to let user change its size?

Check this:

// Define the border style of the form to a dialog box.
form1.FormBorderStyle = FormBorderStyle.FixedDialog;

// Set the MaximizeBox to false to remove the maximize box.
form1.MaximizeBox = false;

// Set the MinimizeBox to false to remove the minimize box.
form1.MinimizeBox = false;

// Set the start position of the form to the center of the screen.
form1.StartPosition = FormStartPosition.CenterScreen;

// Display the form as a modal dialog box.

Using pip behind a proxy with CNTLM

Under Windows dont forget to set

SET HTTPS_PROXY=<proxyHost>:<proxyPort>

what I needed to set for

pip install pep8

When using a Settings.settings file in .NET, where is the config actually stored?

All your settings are stored in the respective .config file.

The .settings file simply provides a strongly typed class for a set of settings that belong together, but the actual settings are stored in app.config or a .config file in your application.

If you add a .settings file, an app.config will be automatically added to house the settings if you don't already have one.

regular expression for Indian mobile numbers

Solutions(^[789]\d{9}$ or ^[789][0-9]{9}$) told by others have a one big flow (If that is used for form validation) It also validates numbers having more than 10 digit. Basically our(Because I was also using this) regex finds a valid number placed anywhere in a string.Like this 123456989796959412345 .

The problem can be solved by additionally checking length of string containing number. Like this if(regex.test(value) && value.length==10)/****do whatever*****/alert("Valid Number");

Note:- According to my tests , the regex.test(value) tests only roman numerals for this expression ^[789]\d{9}$ in both firefox(mozilla) and chrome(webkit)

How to export data to CSV in PowerShell?

This solution creates a psobject and adds each object to an array, it then creates the csv by piping the contents of the array through Export-CSV.

$results = @()
foreach ($computer in $computerlist) {
    if((Test-Connection -Cn $computer -BufferSize 16 -Count 1 -ea 0 -quiet))
        foreach ($file in $REMOVE) {
            Remove-Item "\\$computer\$DESTINATION\$file" -Recurse
            Copy-Item E:\Code\powershell\shortcuts\* "\\$computer\$DESTINATION\"            
    } else {

        $details = @{            
                Date             = get-date              
                ComputerName     = $Computer                 
                Destination      = $Destination 
        $results += New-Object PSObject -Property $details  
$results | export-csv -Path c:\temp\so.csv -NoTypeInformation

If you pipe a string object to a csv you will get its length written to the csv, this is because these are properties of the string, See here for more information.

This is why I create a new object first.

Try the following:

write-output "test" | convertto-csv -NoTypeInformation

This will give you:


If you use the Get-Member on Write-Output as follows:

write-output "test" | Get-Member -MemberType Property

You will see that it has one property - 'length':

   TypeName: System.String

Name   MemberType Definition
----   ---------- ----------
Length Property   System.Int32 Length {get;}

This is why Length will be written to the csv file.

Update: Appending a CSV Not the most efficient way if the file gets large...

$csvFileName = "c:\temp\so.csv"
$results = @()
if (Test-Path $csvFileName)
    $results += Import-Csv -Path $csvFileName
foreach ($computer in $computerlist) {
    if((Test-Connection -Cn $computer -BufferSize 16 -Count 1 -ea 0 -quiet))
        foreach ($file in $REMOVE) {
            Remove-Item "\\$computer\$DESTINATION\$file" -Recurse
            Copy-Item E:\Code\powershell\shortcuts\* "\\$computer\$DESTINATION\"            
    } else {

        $details = @{            
                Date             = get-date              
                ComputerName     = $Computer                 
                Destination      = $Destination 
        $results += New-Object PSObject -Property $details  
$results | export-csv -Path $csvFileName -NoTypeInformation

How can I generate UUID in C#

Here is a client side "sequential guid" solution.

using System;
using System.Runtime.InteropServices;

namespace MyCompany.MyTechnology.Framework.CrossDomain.GuidExtend
    public static class Guid


        Original Reference for Code:


        [DllImport("rpcrt4.dll", SetLastError = true)]
        static extern int UuidCreateSequential(out System.Guid guid);

        public static System.Guid NewGuid()
            return CreateSequentialUuid();

        public static System.Guid CreateSequentialUuid()
            const int RPC_S_OK = 0;
            System.Guid g;
            int hr = UuidCreateSequential(out g);
            if (hr != RPC_S_OK)
                throw new ApplicationException("UuidCreateSequential failed: " + hr);
            return g;


        Text From URL above:

        UuidCreateSequential (rpcrt4)

        Type a page name and press Enter. You'll jump to the page if it exists, or you can create it if it doesn't.
        To create a page in a module other than rpcrt4, prefix the name with the module name and a period.
        . Summary
        Creates a new UUID 
        C# Signature:
        [DllImport("rpcrt4.dll", SetLastError=true)]
        static extern int UuidCreateSequential(out Guid guid);

        VB Signature:
        Declare Function UuidCreateSequential Lib "rpcrt4.dll" (ByRef id As Guid) As Integer

        User-Defined Types:

        Microsoft changed the UuidCreate function so it no longer uses the machine's MAC address as part of the UUID. Since CoCreateGuid calls UuidCreate to get its GUID, its output also changed. If you still like the GUIDs to be generated in sequential order (helpful for keeping a related group of GUIDs together in the system registry), you can use the UuidCreateSequential function.

        CoCreateGuid generates random-looking GUIDs like these:


        UuidCreateSequential generates sequential GUIDs like these:


        Here is a summary of the differences in the output of UuidCreateSequential:

        The last six bytes reveal your MAC address 
        Several GUIDs generated in a row are sequential 
        Tips & Tricks:
        Please add some!

        Sample Code in C#:
        static Guid UuidCreateSequential()
           const int RPC_S_OK = 0;
           Guid g;
           int hr = UuidCreateSequential(out g);
           if (hr != RPC_S_OK)
             throw new ApplicationException
               ("UuidCreateSequential failed: " + hr);
           return g;

        Sample Code in VB:
        Sub Main()
           Dim myId As Guid
           Dim code As Integer
           code = UuidCreateSequential(myId)
           If code <> 0 Then
             Console.WriteLine("UuidCreateSequential failed: {0}", code)
           End If
        End Sub



Keywords: CreateSequentialUUID SequentialUUID

How do you add multi-line text to a UIButton?

In Swift 5.0 and Xcode 10.2

//UIButton extension
extension UIButton {
     //UIButton properties
     func btnMultipleLines() {
         titleLabel?.numberOfLines = 0
         titleLabel?.lineBreakMode = .byWordWrapping
         titleLabel?.textAlignment = .center        

In your ViewController call like this

button.btnMultipleLines()//This is your button

How to find common elements from multiple vectors?

intersect_all <- function(a,b,...){
  all_data <- c(a,b,...)
  count_data<- length(list(a,b,...))
  freq_dist <- count(all_data)
  intersect_data <- freq_dist[which(freq_dist$freq==count_data),"x"]


UPDATE EDIT A simpler code

intersect_all <- function(a,b,...){
  Reduce(intersect, list(a,b,...))


How to concatenate string and int in C?

Strings are hard work in C.

#include <stdio.h>

int main()
   int i;
   char buf[12];

   for (i = 0; i < 100; i++) {
      snprintf(buf, 12, "pre_%d_suff", i); // puts string into buffer
      printf("%s\n", buf); // outputs so you can see it

The 12 is enough bytes to store the text "pre_", the text "_suff", a string of up to two characters ("99") and the NULL terminator that goes on the end of C string buffers.

This will tell you how to use snprintf, but I suggest a good C book!

Easy way to use variables of enum types as string in C?

The technique from Making something both a C identifier and a string? can be used here.

As usual with such preprocessor stuff, writing and understanding the preprocessor part can be hard, and includes passing macros to other macros and involves using # and ## operators, but using it is real easy. I find this style very useful for long enums, where maintaining the same list twice can be really troublesome.

Factory code - typed only once, usually hidden in the header:


// expansion macro for enum value definition
#define ENUM_VALUE(name,assign) name assign,

// expansion macro for enum to string conversion
#define ENUM_CASE(name,assign) case name: return #name;

// expansion macro for string to enum conversion
#define ENUM_STRCMP(name,assign) if (!strcmp(str,#name)) return name;

/// declare the access function and define enum values
#define DECLARE_ENUM(EnumType,ENUM_DEF) \
  enum EnumType { \
  }; \
  const char *GetString(EnumType dummy); \
  EnumType Get##EnumType##Value(const char *string); \

/// define the access function names
#define DEFINE_ENUM(EnumType,ENUM_DEF) \
  const char *GetString(EnumType value) \
  { \
    switch(value) \
    { \
      default: return ""; /* handle input error */ \
    } \
  } \
  EnumType Get##EnumType##Value(const char *str) \
  { \
    return (EnumType)0; /* handle input error */ \
  } \

Factory used


#include "enumFactory.h"
#define SOME_ENUM(XX) \
    XX(FirstValue,) \
    XX(SecondValue,) \
    XX(SomeOtherValue,=50) \
    XX(OneMoreValue,=100) \



#include "someEnum.h"

The technique can be easily extended so that XX macros accepts more arguments, and you can also have prepared more macros to substitute for XX for different needs, similar to the three I have provided in this sample.

Comparison to X-Macros using #include / #define / #undef

While this is similar to X-Macros others have mentioned, I think this solution is more elegant in that it does not require #undefing anything, which allows you to hide more of the complicated stuff is in the factory the header file - the header file is something you are not touching at all when you need to define a new enum, therefore new enum definition is a lot shorter and cleaner.

Save each sheet in a workbook to separate CSV files

Please look into Von Pookie's answer, all credits to him/her.

 Sub asdf()
Dim ws As Worksheet, newWb As Workbook

Application.ScreenUpdating = False
For Each ws In Sheets(Array("EID Upload", "Wages with Locals Upload", "Wages without Local Upload"))
   Set newWb = ActiveWorkbook
   With newWb
      .SaveAs ws.Name, xlCSV
      .Close (False)
   End With
Next ws
Application.ScreenUpdating = True

End Sub

.autocomplete is not a function Error

Sounds like autocomplete is being called before the library that defines it is actually loaded - if that makes sense?

If your script is inline, rather than referenced, move it to the bottom of the page. Or (my preferred option) place the script in an external .js file and then reference it:

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

Edit: if you externalise your script, ensure it is referenced AFTER any JQuery libraries it relies on :)

How to recursively list all the files in a directory in C#?

To avoid the UnauthorizedAccessException, I use:

var files = GetFiles(@"C:\", "*.*", SearchOption.AllDirectories);
foreach (var file in files)

public static IEnumerable<string> GetFiles(string path, string searchPattern, SearchOption searchOption)
    var foldersToProcess = new List<string>()

    while (foldersToProcess.Count > 0)
        string folder = foldersToProcess[0];

        if (searchOption.HasFlag(SearchOption.AllDirectories))
            //get subfolders
                var subfolders = Directory.GetDirectories(folder);
            catch (Exception ex)
                //log if you're interested

        //get files
        var files = new List<string>();
            files = Directory.GetFiles(folder, searchPattern, SearchOption.TopDirectoryOnly).ToList();
        catch (Exception ex)
            //log if you're interested

        foreach (var file in files)
            yield return file;

Get total of Pandas column

As other option, you can do something like below

Group   Valuation   amount
    0   BKB Tube    156
    1   BKB Tube    143
    2   BKB Tube    67
    3   BAC Tube    176
    4   BAC Tube    39
    5   JDK Tube    75
    6   JDK Tube    35
    7   JDK Tube    155
    8   ETH Tube    38
    9   ETH Tube    56

Below script, you can use for above data

import pandas as pd    
data = pd.read_csv("daata1.csv")
bytreatment = data.groupby('Group')

How to find whether a number belongs to a particular range in Python?

I would use the numpy library, which would allow you to do this for a list of numbers as well:

from numpy import array
a = array([1, 2, 3, 4, 5, 6,])
a[a < 2]

How to best display in Terminal a MySQL SELECT returning too many fields?

You can use tee to write the result of your query to a file:

tee somepath\filename.txt

How to start a stopped Docker container with a different command?

This is not exactly what you're asking for, but you can use docker export on a stopped container if all you want is to inspect the files.

docker export $CONTAINER_ID | tar -x -C $TARGET_DIR

Google Chrome forcing download of "f.txt" file

I experienced the same issue, same version of Chrome though it's unrelated to the issue. With the developer console I captured an instance of the request that spawned this, and it is an API call served by Specifically, this resource returns a response with Content-Disposition: attachment; filename="f.txt".

The URL I happened to capture was;sz=300x60...

Per curl:

$ curl -I ';sz=300x60;click=;ord=435266097?'
HTTP/1.1 200 OK
Date: Fri, 20 Feb 2015 23:35:38 GMT
Pragma: no-cache
Expires: Fri, 01 Jan 1990 00:00:00 GMT
Cache-Control: no-cache, must-revalidate
Content-Type: text/javascript; charset=ISO-8859-1
X-Content-Type-Options: nosniff
Content-Disposition: attachment; filename="f.txt"
Server: cafe
X-XSS-Protection: 1; mode=block
Set-Cookie: test_cookie=CheckForPermission; expires=Fri, 20-Feb-2015 23:50:38 GMT; path=/;
Alternate-Protocol: 443:quic,p=0.08
Transfer-Encoding: chunked
Accept-Ranges: none
Vary: Accept-Encoding

Error: Specified cast is not valid. (SqlManagerUI)

This would also happen when you are trying to restore a newer version backup in a older SQL database. For example when you try to restore a DB backup that is created in 2012 with 110 compatibility and you are trying to restore it in 2008 R2.

Running javascript in Selenium using Python

Use execute_script, here's a python example:

from selenium import webdriver
driver = webdriver.Firefox()

Py_Initialize fails - unable to load the file system codec

For me this happened when I updated Python 64 bit from 3.6.4 to 3.6.5. It threw some error like "unable to extract python.dll. Do you have permissions."

Pycharm also failed to load interpreter, even though I reloaded it in settings. Running python command gave same error, with and without administrator mode.


There was error in installation of Python, include folder in python installation directory C:\Users\USERNAME\AppData\Local\Programs\Python\Python36 was missing

Reinstalling Python also dint solve the issue.(Not removal and install)


Uninstall Python and Install of Python again.

Because running installer was just extracting same files excluding include folder

Is it possible to clone html element objects in JavaScript / JQuery?

Get the HTML of the element to clone with .innerHTML, and then just make a new object by means of createElement()...

var html = document.getElementById('test').innerHTML;
var clone = document.createElement('span');
clone.innerHTML = html;

In general, clone() functions must be coded by, or understood by, the cloner. For example, let's clone this: <div>Hello, <span>name!</span></div>. If I delete the clone's <span> tags, should it also delete the original's span tags? If both are deleted, the object references were cloned; if only one set is deleted, the object references are brand-new instantiations. In some cases you want one, in others the other.

In HTML, typically, you'll want anything cloned to be referentially self-contained. The best way to make sure these new references are contained properly is to have the same innerHTML rerun and re-understood by the browser within a new element. Better than working to solve your problem, you should know exactly how it's doing its cloning...

Full Working Demo:

function cloneElement() {
    var html = document.getElementById('test').innerHTML;
    var clone = document.createElement('span');
    clone.innerHTML = html;
<span id="test">Hello!!!</span><br><br>

<span id="clones"></span><br><br>

<input type="button" onclick="cloneElement();" value="Click Here to Clone an Element">

Open multiple Eclipse workspaces on the Mac

If the question is how to easily use Eclipse with multiple different workspaces, then you have to use a kludge because shortcuts in OS X do not provide a mechanism for passing command line arguments, for example the "--data" argument that Eclipse takes to specify the workspace. While there may be different reasons to create a duplicate copy of your Eclipse install, doing it for this purpose is, IMNSHO, lame (now you have to maintain multiple eclipse configurations, plugins, etc?).

In any case, here is a workaround. Create the following script in the (single) Eclipse directory (the directory that contains, and give it a ".command" suffix (e.g. eclipse-workspace2.command) so that you can create an alias from it:

# open, as suggested by Milhous
open -n $(dirname $0)/ --args -data /path/to/your/other/workspace

Now create an alias to that file on your desktop or wherever you want it. You will probably have to repeat this process for each different workspace, but at least it will use the same Eclipse installation.

How do you force a CIFS connection to unmount

On RHEL 6 this worked:

umount -f -a -t cifs -l 

adding multiple event listeners to one element

I know this is an old question, but I thought some might find this approach useful; it could be applied to any similarly repetitive code:


['click','ontouchstart'].forEach( evt => 
    element.addEventListener(evt, dosomething, false)


['click','ontouchstart'].forEach( function(evt) {
    element.addEventListener(evt, dosomething, false);

go to character in vim

:goto 21490 will take you to the 21490th byte in the buffer.

Trying to start a service on boot on Android

How to start service on device boot(autorun app, etc.)

For first: since version Android 3.1+ you don't receive BOOT_COMPLETE if user never started your app at least once or user "force closed" application. This was done to prevent malware automatically register service. This security hole was closed in newer versions of Android.


Create app with activity. When user run it once app can receive BOOT_COMPLETE broadcast message.

For second: BOOT_COMPLETE is sent before external storage is mounted. If app is installed to external storage it won't receive BOOT_COMPLETE broadcast message.

In this case there is two solution:

  1. Install your app to internal storage
  2. Install another small app in internal storage. This app receives BOOT_COMPLETE and run second app on external storage.

If your app already installed in internal storage then code below can help you understand how to start service on device boot.

In Manifest.xml


<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

Register your BOOT_COMPLETED receiver:

<receiver android:name="org.yourapp.OnBoot">
        <action android:name="android.intent.action.BOOT_COMPLETED"/>

Register your service:

<service android:name="org.yourapp.YourCoolService" />

In receiver

public class OnBoot extends BroadcastReceiver

    public void onReceive(Context context, Intent intent) 
        // Create Intent
        Intent serviceIntent = new Intent(context, YourCoolService.class);
        // Start service



For HTC you maybe need also add in Manifest this code if device don't catch RECEIVE_BOOT_COMPLETED:

<action android:name="android.intent.action.QUICKBOOT_POWERON" />

Receiver now look like this:

<receiver android:name="org.yourapp.OnBoot">
        <action android:name="android.intent.action.BOOT_COMPLETED"/>
        <action android:name="android.intent.action.QUICKBOOT_POWERON" />

How to test BOOT_COMPLETED without restart emulator or real device? It's easy. Try this:

adb -s device-or-emulator-id shell am broadcast -a android.intent.action.BOOT_COMPLETED

How to get device id? Get list of connected devices with id's:

adb devices

adb in ADT by default you can find in:


Enjoy! )

Partial Dependency (Databases)

Partial dependency implies is a situation where a non-prime attribute(An attribute that does not form part of the determinant(Primary key/Candidate key)) is functionally dependent to a portion/part of a primary key/Candidate key.

Sharing a variable between multiple different threads

  1. Making it static could fix this issue.
  2. Reference to the main thread in other thread and making that variable visible

Cron job every three days

I am not a cron specialist, but how about:

0 */72 * * *

It will run every 72 hours non-interrupted.

How to split the name string in mysql?

Combined a few answers here to create a SP that returns the parts of the string.

drop procedure if exists SplitStr;
        DECLARE inipos INT;
        DECLARE endpos INT;
        DECLARE maxlen INT;
        DECLARE fullstr VARCHAR(2000);
        DECLARE item VARCHAR(2000);
        create temporary table if not exists tb_split
            item varchar(2000)

        SET inipos = 1;
        SET fullstr = CONCAT(Str, delim);
        SET maxlen = LENGTH(fullstr);

            SET endpos = LOCATE(delim, fullstr, inipos);
            SET item =  SUBSTR(fullstr, inipos, endpos - inipos);

            IF item <> '' AND item IS NOT NULL THEN           
                insert into tb_split values(item);
            END IF;
            SET inipos = endpos + 1;
        UNTIL inipos >= maxlen END REPEAT;

        SELECT * from tb_split;
        drop table tb_split;

What’s the best way to get an HTTP response code from a URL?

Update using the wonderful requests library. Note we are using the HEAD request, which should happen more quickly then a full GET or POST request.

import requests
    r = requests.head("")
    # prints the int of the status code. Find more at :)
except requests.ConnectionError:
    print("failed to connect")

HTML5 Canvas and Anti-aliasing

It's now 2018, and we finally have cheap ways to do something around it...

Indeed, since the 2d context API now has a filter property, and that this filter property can accept SVGFilters, we can build an SVGFilter that will keep only fully opaque pixels from our drawings, and thus eliminate the default anti-aliasing.

So it won't deactivate antialiasing per se, but provides a cheap way both in term of implementation and of performances to remove all semi-transparent pixels while drawing.

I am not really a specialist of SVGFilters, so there might be a better way of doing it, but for the example, I'll use a <feComponentTransfer> node to grab only fully opaque pixels.

var ctx = canvas.getContext('2d');_x000D_
ctx.fillStyle = '#ABEDBE';_x000D_
ctx.fillStyle = 'black';_x000D_
ctx.font = '14px sans-serif';_x000D_
ctx.textAlign = 'center';_x000D_
// first without filter_x000D_
ctx.fillText('no filter', 60, 20);_x000D_
// then with filter_x000D_
ctx.setTransform(1, 0, 0, 1, 120, 0);_x000D_
ctx.filter = 'url(#remove-alpha)';_x000D_
// and do the same ops_x000D_
ctx.fillText('no alpha', 60, 20);_x000D_
// to remove the filter_x000D_
ctx.filter = 'none';_x000D_
function drawArc() {_x000D_
  ctx.arc(60, 80, 50, 0, Math.PI * 2);_x000D_
function drawTriangle() {_x000D_
  ctx.moveTo(60, 150);_x000D_
  ctx.lineTo(110, 230);_x000D_
  ctx.lineTo(10, 230);_x000D_
// unrelated_x000D_
// simply to show a zoomed-in version_x000D_
var zCtx = zoomed.getContext('2d');_x000D_
zCtx.imageSmoothingEnabled = false;_x000D_
canvas.onmousemove = function drawToZoommed(e) {_x000D_
  var x = e.pageX - this.offsetLeft,_x000D_
    y = e.pageY - this.offsetTop,_x000D_
    w = this.width,_x000D_
    h = this.height;_x000D_
  zCtx.drawImage(this, x-w/6,y-h/6,w, h, 0,0,w*3, h*3);_x000D_
<svg width="0" height="0" style="position:absolute;z-index:-1;">_x000D_
    <filter id="remove-alpha" x="0" y="0" width="100%" height="100%">_x000D_
        <feFuncA type="discrete" tableValues="0 1"></feFuncA>_x000D_
<canvas id="canvas" width="250" height="250" ></canvas>_x000D_
<canvas id="zoomed" width="250" height="250" ></canvas>

And for the ones that don't like to append an <svg> element in their DOM, you can also save it as an external svg file and set the filter property to path/to/svg_file.svg#remove-alpha.

No increment operator (++) in Ruby?

From a posting by Matz:

(1) ++ and -- are NOT reserved operator in Ruby.

(2) C's increment/decrement operators are in fact hidden assignment. They affect variables, not objects. You cannot accomplish assignment via method. Ruby uses +=/-= operator instead.

(3) self cannot be a target of assignment. In addition, altering the value of integer 1 might cause severe confusion throughout the program.


Function that creates a timestamp in c#

If you want timestamps that correspond to actual real times BUT also want them to be unique (for a given application instance), you can use the following code:

public class HiResDateTime
   private static long lastTimeStamp = DateTime.UtcNow.Ticks;
   public static long UtcNowTicks
           long orig, newval;
               orig = lastTimeStamp;
               long now = DateTime.UtcNow.Ticks;
               newval = Math.Max(now, orig + 1);
           } while (Interlocked.CompareExchange
                        (ref lastTimeStamp, newval, orig) != orig);

           return newval;

How to get the groups of a user in Active Directory? (c#,

Within the AD every user has a property memberOf. This contains a list of all groups he belongs to.

Here is a little code example:

// (replace "part_of_user_name" with some partial user name existing in your AD)
var userNameContains = "part_of_user_name";

var identity = WindowsIdentity.GetCurrent().User;
var allDomains = Forest.GetCurrentForest().Domains.Cast<Domain>();

var allSearcher = allDomains.Select(domain =>
    var searcher = new DirectorySearcher(new DirectoryEntry("LDAP://" + domain.Name));

    // Apply some filter to focus on only some specfic objects
    searcher.Filter = String.Format("(&(&(objectCategory=person)(objectClass=user)(name=*{0}*)))", userNameContains);
    return searcher;

var directoryEntriesFound = allSearcher
    .SelectMany(searcher => searcher.FindAll()
        .Select(result => result.GetDirectoryEntry()));

var memberOf = directoryEntriesFound.Select(entry =>
    using (entry)
        return new
            Name = entry.Name,
            GroupName = ((object[])entry.Properties["MemberOf"].Value).Select(obj => obj.ToString())

foreach (var item in memberOf)
    Debug.Print("Name = " + item.Name);
    Debug.Print("Member of:");

    foreach (var groupName in item.GroupName)
        Debug.Print("   " + groupName);


What's the quickest way to multiply multiple cells by another number?

To multiply a column of numbers with a constant(same number), I have done like this.

Let C2 to C12 be different numbers which need to be multiplied by a single number (constant). Then type the numbers from C2 to C12.


C       D       E=PRODUCT(C2:C12,20)

25  1   500
30      600
35      700
40      800
45      900
50      1000
55      1100
60      1200
65      1300
70      1400
75      1500

Angular ng-if not true

you are not using the $scope you must use $ctrl.area or $scope.area instead of area

Call Activity method from adapter

One more way is::

Write a method in your adapter lets say public void callBack(){}.

Now while creating an object for adapter in activity override this method. Override method will be called when you call the method in adapter.

Myadapter adapter = new Myadapter() {
  public void callBack() {
    // dosomething

Delaying a jquery script until everything else has loaded

You can have $(document).ready() multiple times in a page. The code gets run in the sequence in which it appears.

You can use the $(window).load() event for your code since this happens after the page is fully loaded and all the code in the various $(document).ready() handlers have finished running.

  //your code here

Add Items to Columns in a WPF ListView

Solution With Less XAML and More C#

If you define the ListView in XAML:

<ListView x:Name="listView"/>

Then you can add columns and populate it in C#:

public Window()
    // Initialize

    // Add columns
    var gridView = new GridView();
    this.listView.View = gridView;
    gridView.Columns.Add(new GridViewColumn { 
        Header = "Id", DisplayMemberBinding = new Binding("Id") });
    gridView.Columns.Add(new GridViewColumn { 
        Header = "Name", DisplayMemberBinding = new Binding("Name") });

    // Populate list
    this.listView.Items.Add(new MyItem { Id = 1, Name = "David" });

See definition of MyItem below.

Solution With More XAML and less C#

However, it's easier to define the columns in XAML (inside the ListView definition):

<ListView x:Name="listView">
            <GridViewColumn Header="Id" DisplayMemberBinding="{Binding Id}"/>
            <GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}"/>

And then just populate the list in C#:

public Window()
    // Initialize

    // Populate list
    this.listView.Items.Add(new MyItem { Id = 1, Name = "David" });

See definition of MyItem below.

MyItem Definition

MyItem is defined like this:

public class MyItem
    public int Id { get; set; }

    public string Name { get; set; }

Text on image mouseover?

Here is one way to do this using css


<div class="imageWrapper">
    <img src="" alt="" />
    <a href="" class="cornerLink">Link</a>


.imageWrapper {
    position: relative;
    width: 300px;
    height: 300px;
.imageWrapper img {
    display: block;
.imageWrapper .cornerLink {
    opacity: 0;
    position: absolute;
    bottom: 0px;
    left: 0px;
    right: 0px;
    padding: 2px 0px;
    color: #ffffff;
    background: #000000;
    text-decoration: none;
    text-align: center;
    -webkit-transition: opacity 500ms;
    -moz-transition: opacity 500ms;
    -o-transition: opacity 500ms;
    transition: opacity 500ms;

.imageWrapper:hover .cornerLink {
    opacity: 0.8;


Or if you just want it in the bottom left corner:


Turn ON/OFF Camera LED/flash light in Samsung Galaxy Ace 2.2.1 & Galaxy Tab

I will soon released a new version of my app to support to galaxy ace.

You can download here:

In order to solve your problem you should do this:

this._camera =;     
this._camera.autoFocus(new AutoFocusCallback() {
public void onAutoFocus(boolean success, Camera camera) {

Parameters params = this._camera.getParameters();

params = this._camera.getParameters();

don't worry about FLASH_MODE_OFF because this will keep the light on, strange but it's true

to turn off the led just release the camera

How to change line width in ggplot?

Line width in ggplot2 can be changed with argument size= in geom_line().

#sample data

enter image description here

How to check View Source in Mobile Browsers (Both Android && Feature Phone)

The view-source url prefix trick didn't work for me using chrome on an iphone. There are apps I could have installed to do this I guess but for whatever reason I just preferred to do it myself rather than install 'yet another app'.

I found this nice quick tutorial for how to setup a bookmark on mobile safari that will automatically open the view source of a page:

It worked flawlessly for me and now I have it set as a permanent bookmark any time I want, with no app installed.

Edit: There are basically 6 steps which should work for either Chrome or Safari. Instructions for Safari are:

  1. Open Safari and browse to an arbitrary page.
  2. Select the "Share" (or action") button in Safari (looks like a square with an arrow coming out of the top).
  3. Select "Add Bookmark"
  4. Delete the page title and replace it with something useful like "Show Page Source". Click Save.
  5. Next browse to this exact Stack Overflow answer on your phone and copy the javascript code below to your phone clipboard (code credit: Rob Flaherty):
javascript:(function(){var'about:blank').document;a.write('<!DOCTYPE html><html><head><title>Source of '+location.href+'</title><meta name="viewport" content="width=device-width" /></head><body></body></html>');a.close();var b=a.body.appendChild(a.createElement('pre'));'auto';'pre-wrap';b.appendChild(a.createTextNode(document.documentElement.innerHTML))})();
  1. Open the "Bookmarks" in Safari and opt to Edit the newly created Show Page Source bookmark. Delete whatever was previously saved in the Address field and instead paste in the Javascript code. Save it.
  2. (Optional) Profit!

Regular expression "^[a-zA-Z]" or "[^a-zA-Z]"

Yes, the first means "match all strings that start with a letter", the second means "match all strings that contain a non-letter". The caret ("^") is used in two different ways, one to signal the start of the text, one to negate a character match inside square brackets.

Closing Twitter Bootstrap Modal From Angular Controller

You can add data-dismiss="modal" to your button attributes which call angularjs funtion.

Such as;

<button type="button" class="btn btn-default" data-dismiss="modal">Send Form</button>

Read a XML (from a string) and get some fields - Problems reading XML

You should use LoadXml method, not Load:


Load method is trying to load xml from a file and LoadXml from a string. You could also use XPath:

XmlDocument xmlDoc = new XmlDocument();

string xpath = "myDataz/listS/sog";
var nodes = xmlDoc.SelectNodes(xpath);

foreach (XmlNode childrenNode in nodes)

PHP convert string to hex and hex to string


string to hex:

implode(unpack("H*", $string));

hex to string:

pack("H*", $hex);

How to get the Facebook user id using the access token

You can use below code on onSuccess(LoginResult loginResult)


Android: Tabs at the BOTTOM

I was having the same problem with android tabs when trying to place them on the bottom of the screen. My scenario was to not use a layout file and create the tabs in code, I was also looking to fire activities from each tab which seemed a bit too complex using other approaches so, here is the sample code to overcome the problem:


How can I append a string to an existing field in MySQL?

You need to use the CONCAT() function in MySQL for string concatenation:

UPDATE categories SET code = CONCAT(code, '_standard') WHERE id = 1;

Declaring a xsl variable and assigning value to it

No, unlike in a lot of other languages, XSLT variables cannot change their values after they are created. You can however, avoid extraneous code with a technique like this:

<xsl:stylesheet version="1.0" xmlns:xsl="">
  <xsl:output method="xml" indent="yes" omit-xml-declaration="yes"/>

  <xsl:variable name="mapping">
    <item key="1" v1="A" v2="B" />
    <item key="2" v1="X" v2="Y" />
  <xsl:variable name="mappingNode"
                select="document('')//xsl:variable[@name = 'mapping']" />

  <xsl:template match="....">
    <xsl:variable name="testVariable" select="'1'" />

    <xsl:variable name="values" select="$mappingNode/item[@key = $testVariable]" />

    <xsl:variable name="variable1" select="$values/@v1" />
    <xsl:variable name="variable2" select="$values/@v2" />

In fact, once you've got the values variable, you may not even need separate variable1 and variable2 variables. You could just use $values/@v1 and $values/@v2 instead.

ERROR Error: No value accessor for form control with unspecified name attribute on switch

in my case, I had a <TEXTAREA> tag from old html while converting to angular. Had to change to <textarea>.

Undefined reference to vtable

What is a vtable?

It might be useful to know what the error message is talking about before trying to fix it. I'll start at a high level, then work down to some more details. That way people can skip ahead once they are comfortable with their understanding of vtables. …and there goes a bunch of people skipping ahead right now. :) For those sticking around:

A vtable is basically the most common implementation of polymorphism in C++. When vtables are used, every polymorphic class has a vtable somewhere in the program; you can think of it as a (hidden) static data member of the class. Every object of a polymorphic class is associated with the vtable for its most-derived class. By checking this association, the program can work its polymorphic magic. Important caveat: a vtable is an implementation detail. It is not mandated by the C++ standard, even though most (all?) C++ compilers use vtables to implement polymorphic behavior. The details I am presenting are either typical or reasonable approaches. Compilers are allowed to deviate from this!

Each polymorphic object has a (hidden) pointer to the vtable for the object's most-derived class (possibly multiple pointers, in the more complex cases). By looking at the pointer, the program can tell what the "real" type of an object is (except during construction, but let's skip that special case). For example, if an object of type A does not point to the vtable of A, then that object is actually a sub-object of something derived from A.

The name "vtable" comes from "virtual function table". It is a table that stores pointers to (virtual) functions. A compiler chooses its convention for how the table is laid out; a simple approach is to go through the virtual functions in the order they are declared within class definitions. When a virtual function is called, the program follows the object's pointer to a vtable, goes to the entry associated with the desired function, then uses the stored function pointer to invoke the correct function. There are various tricks for making this work, but I won't go into those here.

Where/when is a vtable generated?

A vtable is automatically generated (sometimes called "emitted") by the compiler. A compiler could emit a vtable in every translation unit that sees a polymorphic class definition, but that would usually be unnecessary overkill. An alternative (used by gcc, and probably by others) is to pick a single translation unit in which to place the vtable, similar to how you would pick a single source file in which to put a class' static data members. If this selection process fails to pick any translation units, then the vtable becomes an undefined reference. Hence the error, whose message is admittedly not particularly clear.

Similarly, if the selection process does pick a translation unit, but that object file is not provided to the linker, then the vtable becomes an undefined reference. Unfortunately, the error message can be even less clear in this case than in the case where the selection process failed. (Thanks to the answerers who mentioned this possibility. I probably would have forgotten it otherwise.)

The selection process used by gcc makes sense if we start with the tradition of devoting a (single) source file to each class that needs one for its implementation. It would be nice to emit the vtable when compiling that source file. Let's call that our goal. However, the selection process needs to work even if this tradition is not followed. So instead of looking for the implementation of the entire class, let's look for the implementation of a specific member of the class. If tradition is followed – and if that member is in fact implemented – then this achieves the goal.

The member selected by gcc (and potentially by other compilers) is the first non-inline virtual function that is not pure virtual. If you are part of the crowd that declares constructors and destructors before other member functions, then that destructor has a good chance of being selected. (You did remember to make the destructor virtual, right?) There are exceptions; I'd expect that the most common exceptions are when an inline definition is provided for the destructor and when the default destructor is requested (using "= default").

The astute might notice that a polymorphic class is allowed to provide inline definitions for all of its virtual functions. Doesn't that cause the selection process to fail? It does in older compilers. I've read that the latest compilers have addressed this situation, but I do not know relevant version numbers. I could try looking this up, but it's easier to either code around it or wait for the compiler to complain.

In summary, there are three key causes of the "undefined reference to vtable" error:

  1. A member function is missing its definition.
  2. An object file is not being linked.
  3. All virtual functions have inline definitions.

These causes are by themselves insufficient to cause the error on their own. Rather, these are what you would address to resolve the error. Do not expect that intentionally creating one of these situations will definitely produce this error; there are other requirements. Do expect that resolving these situations will resolve this error.

(OK, number 3 might have been sufficient when this question was asked.)

How to fix the error?

Welcome back people skipping ahead! :)

  1. Look at your class definition. Find the first non-inline virtual function that is not pure virtual (not "= 0") and whose definition you provide (not "= default").
    • If there is no such function, try modifying your class so there is one. (Error possibly resolved.)
    • See also the answer by Philip Thomas for a caveat.
  2. Find the definition for that function. If it is missing, add it! (Error possibly resolved.)
  3. Check your link command. If it does not mention the object file with that function's definition, fix that! (Error possibly resolved.)
  4. Repeat steps 2 and 3 for each virtual function, then for each non-virtual function, until the error is resolved. If you're still stuck, repeat for each static data member.

The details of what to do can vary, and sometimes branch off into separate questions (like What is an undefined reference/unresolved external symbol error and how do I fix it?). I will, though, provide an example of what to do in a specific case that might befuddle newer programmers.

Step 1 mentions modifying your class so that it has a function of a certain type. If the description of that function went over your head, you might be in the situation I intend to address. Keep in mind that this is a way to accomplish the goal; it is not the only way, and there easily could be better ways in your specific situation. Let's call your class A. Is your destructor declared (in your class definition) as either

virtual ~A() = default;


virtual ~A() {}

? If so, two steps will change your destructor into the type of function we want. First, change that line to

virtual ~A();

Second, put the following line in a source file that is part of your project (preferably the file with the class implementation, if you have one):

A::~A() {}

That makes your (virtual) destructor non-inline and not generated by the compiler. (Feel free to modify things to better match your code formatting style, such as adding a header comment to the function definition.)

Multiline for WPF TextBox

Enable TextWrapping="Wrap" and AcceptsReturn="True" on your TextBox.

You might also wish to enable AcceptsTab and SpellCheck.IsEnabled too.

How can I pass command-line arguments to a Perl program?

If the arguments are filenames to be read from, use the diamond (<>) operator to get at their contents:

while (my $line = <>) {

If the arguments are options/switches, use GetOpt::Std or GetOpt::Long, as already shown by

On the off chance that they're something else, you can access them either by walking through @ARGV explicitly or with the shift command:

while (my $arg = shift) {
  print "Found argument $arg\n";

(Note that doing this with shift will only work if you are outside of all subs. Within a sub, it will retrieve the list of arguments passed to the sub rather than those passed to the program.)

undefined reference to `std::ios_base::Init::Init()'

You can resolve this in several ways:

  • Use g++ in stead of gcc: g++ -g -o MatSim MatSim.cpp
  • Add -lstdc++: gcc -g -o MatSim MatSim.cpp -lstdc++
  • Replace <string.h> by <string>

This is a linker problem, not a compiler issue. The same problem is covered in the question iostream linker error – it explains what is going on.

Write and read a list from file

As long as your file has consistent formatting (i.e. line-breaks), this is easy with just basic file IO and string operations:

with open('my_file.txt', 'rU') as in_file:
    data ='\n')

That will store your data file as a list of items, one per line. To then put it into a file, you would do the opposite:

with open('new_file.txt', 'w') as out_file:
    out_file.write('\n'.join(data)) # This will create a string with all of the items in data separated by new-line characters

Hopefully that fits what you're looking for.

Handling the window closing event with WPF / MVVM Light Toolkit

I would simply associate the handler in the View constructor:

    // Set up ViewModel, assign to DataContext etc.
    Closing += viewModel.OnWindowClosing;

Then add the handler to the ViewModel:

using System.ComponentModel;

public void OnWindowClosing(object sender, CancelEventArgs e) 
   // Handle closing logic, set e.Cancel as needed

In this case, you gain exactly nothing except complexity by using a more elaborate pattern with more indirection (5 extra lines of XAML plus Command pattern).

The "zero code-behind" mantra is not the goal in itself, the point is to decouple ViewModel from the View. Even when the event is bound in code-behind of the View, the ViewModel does not depend on the View and the closing logic can be unit-tested.

Animation CSS3: display + opacity

I used this to achieve it. They fade on hover but take no space when hidden, perfect!

.child {
    height: 0px;
    opacity: 0;
    visibility: hidden;
    transition: all .5s ease-in-out;

.parent:hover .child {
    height: auto;
    opacity: 1;
    visibility: visible;

Convert data file to blob

As pointed in the comments, file is a blob:

file instanceof Blob; // true

And you can get its content with the file reader API

Read more:

var input = document.querySelector('input[type=file]');
var textarea = document.querySelector('textarea');

function readFile(event) {
  textarea.textContent =;

function changeFile() {
  var file = input.files[0];
  var reader = new FileReader();
  reader.addEventListener('load', readFile);

input.addEventListener('change', changeFile);
<input type="file">
<textarea rows="10" cols="50"></textarea>

Array.push() and unique items

You can use the Set structure from ES6 to make your code faster and more readable:

// Create Set
this.items = new Set();

add(item) {

    // Set to array

How to format time since xxx e.g. “4 minutes ago” similar to Stack Exchange sites

Much readable and cross browser compatible code:

As given by @Travis

  epochs: ['year', 'month', 'day', 'hour', 'minute'],_x000D_
  year: 31536000,_x000D_
  month: 2592000,_x000D_
  day: 86400,_x000D_
  hour: 3600,_x000D_
  minute: 60_x000D_
function getDuration(seconds) {_x000D_
  var epoch, interval;_x000D_
  for (var i = 0; i < DURATION_IN_SECONDS.epochs.length; i++) {_x000D_
    epoch = DURATION_IN_SECONDS.epochs[i];_x000D_
    interval = Math.floor(seconds / DURATION_IN_SECONDS[epoch]);_x000D_
    if (interval >= 1) {_x000D_
      return {_x000D_
        interval: interval,_x000D_
        epoch: epoch_x000D_
function timeSince(date) {_x000D_
  var seconds = Math.floor((new Date() - new Date(date)) / 1000);_x000D_
  var duration = getDuration(seconds);_x000D_
  var suffix = (duration.interval > 1 || duration.interval === 0) ? 's' : '';_x000D_
  return duration.interval + ' ' + duration.epoch + suffix;_x000D_

XPath: Get parent node from child node

Use the parent axes with the parent node's name.


This XPath will only select the parent node if it is a store.

But you can also use one of these


These xpaths will select any parent node. So if the document changes you will always select a node, even if it is not the node you expect.


What happens in the given example where the parent is a bicycle but the parent of the parent is a store?

Does it ascent?

No, it only selects the store if it is a parent of the node that matches //*[title="50"].

If not, is there a method to ascent in such cases and return None if there is no such parent?

Yes, you can use ancestor axes


This will select all ancestors of the node matching //*[title="50"] that are ` stores. E.g.

<data xmlns:d="defiant-namespace" d:mi="23">
    <store mi="1">
        <store mi="22">
            <book price="8.95" d:price="Number" d:mi="13">
                <title d:constr="String" d:mi="10">50</title>
                <category d:constr="String" d:mi="11">reference</category>
                <author d:constr="String" d:mi="12">Nigel Rees</author>

XPath selection result

AttributeError("'str' object has no attribute 'read'")

Ok, this is an old thread but. I had a same issue, my problem was I used json.load instead of json.loads

This way, json has no problem with loading any kind of dictionary.

Official documentation

json.load - Deserialize fp (a .read()-supporting text file or binary file containing a JSON document) to a Python object using this conversion table.

json.loads - Deserialize s (a str, bytes or bytearray instance containing a JSON document) to a Python object using this conversion table.

asterisk : Unable to connect to remote asterisk (does /var/run/asterisk.ctl exist?)

You have to make a change in the asterisk.conf file located at /etc/asterisk

astrundir => /var/run/asterisk

Reboot your system and check

Hope this helps you

Sum of Numbers C++

try this:

#include <iostream>
using namespace std;

int main()
    int positiveInteger;
    int startingNumber = 1;

    cout << "Please input an integer upto 100." << endl;

    cin >> positiveInteger;

    int result = 0;
    for (int i=startingNumber; i <= positiveInteger; i++)
        result += i;
        cout << result;

    cout << result;

    return 0;


How to get numbers after decimal point?

A solution is using modulo and rounding.

import math

num = math.fabs(float(5.55))
rem = num % 1

rnd_by =   len(str(num)) - len(str(int(num))) - 1


Your output will be 0.55

Zsh: Conda/Pip installs command not found

So I discovered that in your ~/.zshrc file, there was a commented line,

# If you come from bash you might have to change your $PATH # export PATH=$HOME/bin:/usr/local/bin:$PATH

Just uncomment the export statement and all your previous bash_profile commands will also be there. If that comment does not exist, you can also just add that export statement to .zshrc file.

Rails 3 migrations: Adding reference column?

If you are using the Rails 4.x you can now generate migrations with references, like this:

rails generate migration AddUserRefToProducts user:references

like you can see on rails guides

How to round to 2 decimals with Python?

float(str(round(answer, 2)))
float(str(round(0.0556781255, 2)))

Why can I ping a server but not connect via SSH?

Find out two pieces of information

  • Whats the hostname or IP of the target ssh server
  • What port is the ssh daemon listening on (default is port 22)

$> telnet <hostname or ip> <port>

Assuming the daemon is up and running and listening on that port it should etablish a telnet session. Likely causes:

  • The ssh daemon is not running
  • The host is blocking the target port with its software firewall
  • Some intermediate network device is blocking or filtering the target port
  • The ssh daemon is listening on a non standard port
  • A TCP wrapper is configured and is filtering out your source host

Display a view from another controller in ASP.NET MVC

You can also call any controller from JavaScript/jQuery. Say you have a controller returning 404 or some other usercontrol/page. Then, on some action, from your client code, you can call some address that will fire your controller and return the result in HTML format your client code can take this returned result and put it wherever you want in you your page...

Convert string into integer in bash script - "Leading Zero" number error

In Short: In order to deal with "Leading Zero" numbers (any 0 digit that comes before the first non-zero) in bash - Use bc An arbitrary precision calculator language


b=$(echo $a | bc)
echo $b

Output: 1

From Bash manual:

"bc is a language that supports arbitrary precision numbers with interactive execution of statements. There are some similarities in the syntax to the C programming lan- guage. A standard math library is available by command line option. If requested, the math library is defined before processing any files. bc starts by processing code from all the files listed on the command line in the order listed. After all files have been processed, bc reads from the standard input. All code is executed as it is read. (If a file contains a command to halt the processor, bc will never read from the standard input.)"

How to make program go back to the top of the code instead of closing

write a for or while loop and put all of your code inside of it? Goto type programming is a thing of the past.

What does it mean to "call" a function in Python?

When you "call" a function you are basically just telling the program to execute that function. So if you had a function that added two numbers such as:

def add(a,b):
    return a + b

you would call the function like this:


which would return 8. You can put any two numbers in the parentheses in this case. You can also call a function like this:

answer = add(4,7)

Which would set the variable answer equal to 11 in this case.

How to join multiple lines of file names into one with custom delimiter?

I think this one is awesome

ls -1 | awk 'ORS=","'

ORS is the "output record separator" so now your lines will be joined with a comma.

What are the Android SDK build-tools, platform-tools and tools? And which version should be used?

I'll leave the discussion of the difference between Build Tools, Platform Tools, and Tools to others. From a practical standpoint, you only need to know the answer to your second question:

Which version should be used?

Answer: Use the most recent version.

For those using Android Studio with Gradle, the buildToolsVersion has to be set in the build.gradle (Module: app) file.

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"


Where do I get the most recent version number of Build Tools?

Open the Android SDK Manager.

  • In Android Studio go to Tools > Android > SDK Manager > Appearance & Behavior > System Settings > Android SDK
  • Choose the SDK Tools tab.
  • Select Android SDK Build Tools from the list
  • Check Show Package Details.

The last item will show the most recent version.

enter image description here

Make sure it is installed and then write that number as the buildToolsVersion in build.gradle (Module: app).

PackagesNotFoundError: The following packages are not available from current channels:

Have you tried:

pip install <package>


conda install -c conda-forge <package>

CSS fixed width in a span

You can do it using a table, but it is not pure CSS.

    text-indent: 40px;

    list-style-type: none;
    padding: 0;

    color: #ff0000;
    position: relative;
    left: -40px;

<span></span><li>The lazy dog.</li>
<span>AND</span><li>The lazy cat.</li>
<span>OR</span><li>The active goldfish.</li>

Note that it doesn't display exactly like you want, because it switches line on each option. However, I hope that this helps you come closer to the answer.

Create zip file and ignore directory structure

Retain the parent directory so unzip doesn't spew files everywhere

When zipping directories, keeping the parent directory in the archive will help to avoid littering your current directory when you later unzip the archive file

So to avoid retaining all paths, and since you can't use -j and -r together ( you'll get an error ), you can do this instead:

cd path/to/parent/dir/;
zip -r ../ ../$(basename $PWD)
cd -;

The ../$(basename $PWD) is the magic that retains the parent directory.

So now unzip will give a folder containing all your files:

+-- file1
+-- file2
+-- dir1
¦   +-- file3
¦   +-- file4

Instead of littering the current directory with the unzipped files:

+-- file3
+-- file4

JavaScript Array to Set

Just pass the array to the Set constructor. The Set constructor accepts an iterable parameter. The Array object implements the iterable protocol, so its a valid parameter.

var arr = [55, 44, 65];_x000D_
var set = new Set(arr);_x000D_
console.log(set.size === arr.length);_x000D_

See here

Is there an exponent operator in C#?

I'm surprised no one has mentioned this, but for the simple (and probably most encountered) case of squaring, you just multiply by itself.

float someNumber;

float result = someNumber * someNumber;

How to get the exact local time of client?

In JavaScript? Just instantiate a new Date object

var now = new Date();

That will create a new Date object with the client's local time.

Verify object attribute value with mockito

I think the easiest way for verifying an argument object is to use the refEq method:


It can be used even if the object doesn't implement equals(), because reflection is used. If you don't want to compare some fields, just add their names as arguments for refEq.

How to update/refresh specific item in RecyclerView

In your adapter class, in onBindViewHolder method, set ViewHolder to setIsRecyclable(false) as in below code.

public void onBindViewHolder(RecyclerViewAdapter.ViewHolder p1, int p2)
    // TODO: Implement this method

    // Then your other codes

How to margin the body of the page (html)?

Yeah a CSS primer will not hurt here so you can do two things: 1 - within the tags of your html you can open a style tag like this:

<style type="text/css">
  body {
   margin: 0px;
   * this is the same as writing
   * body { margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;}
   * I'm adding px here for clarity sake but the unit is not really needed if you have 0
   * look into em, pt and % for other unit types 
   * the rules are always clockwise: top, right, bottom, left

2- the above though will only work on the page you have this code embeded, so if if you wanted to reuse this in 10 files, then you will have to copy it over on all 10 files, and if you wanted to make a change let's say have a margin of 5px instead, you would have to open all those files and make the edit. That's why using an external style sheet is a golden rule in front end coding. So save the body declaration in a separate file named style.css for example and from your add this to your html instead:

<link rel="stylesheet" type="text/css" href="style.css"/>

Now you can put this in the of all pages that will benefit from these styles and whenever needed to change them you will only need to do so in one place. Hope it helps. Cheers

What is the best way to prevent session hijacking?

Try Secure Cookie protocol described in this paper by Liu, Kovacs, Huang, and Gouda:

As stated in document:

A secure cookie protocol that runs between a client and a server needs to provide the following four services: authentication, confidentiality, integrity and anti-replay.

As for ease of deployment:

In terms of efficiency, our protocol does not involve any database lookup or public key cryptography. In terms of deployability, our protocol can be easily deployed on an existing web server, and it does not require any change to the Internet cookie specication.

In short: it is secure, lightweight, works for me just great.

Convert base-2 binary number string to int

You use the built-in int function, and pass it the base of the input number, i.e. 2 for a binary number:

>>> int('11111111', 2)

Here is documentation for python2, and for python3.

SVN Error - Not a working copy

Had this same problem, turns out we had Slik 1.6.2 as well as Tortoise on the same machine. Tortoise had been updated (and had updated the working copy) but Slik had not, so Tortoise worked OK, but command lines failed with:

svn: '.' is not a working copy directory

Removing both Tortoise and Slik, then reinstalling Tortoise with command line tools enabled fixed this for me.

Multiple REPLACE function in Oracle

Even if this thread is old is the first on Google, so I'll post an Oracle equivalent to the function implemented here, using regular expressions.

Is fairly faster than nested replace(), and much cleaner.

To replace strings 'a','b','c' with 'd' in a string column from a given table

select regexp_replace(string_col,'a|b|c','d') from given_table

It is nothing else than a regular expression for several static patterns with 'or' operator.

Beware of regexp special characters!

ArrayList of String Arrays

private List<String[]> addresses = new ArrayList<String[]>();

this will work defenitely...

How do I install a JRE or JDK to run the Android Developer Tools on Windows 7?

The most likely reason why the Java Runtime Environment JRE or Java Development Kit JDK is that it's owned by Oracle not Google and they would need a redistribution agreement which if you know there is some history between the two companies.

Lucky for us that Sun Microsystems before it was bought by Oracle open sourced Java and MySQL a win for us little guys.... Thank you Sun!

Google should probably have a caveat saying you may also need JRE OR JDK

How to define and use function inside Jenkins Pipeline config?

Solved! The call build job: project, parameters: params fails with an error java.lang.UnsupportedOperationException: must specify $class with an implementation of interface java.util.List when params = [:]. Replacing it with params = null solved the issue. Here the working code below.

def doCopyMibArtefactsHere(projectName) {
    step ([
        $class: 'CopyArtifact',
        projectName: projectName,
        filter: '**/**.mib',
        fingerprintArtifacts: true, 
        flatten: true

def BuildAndCopyMibsHere(projectName, params = null) {
    build job: project, parameters: params
node { 
    stage('Prepare Mib'){

How to delete all rows from all tables in a SQL Server database?

--Load tables to delete from
' Delete top 1000000 from <DBName>.<schema>.' + c.TABLE_NAME + ' WHERE <Filter Clause Here>' AS query,c.TABLE_NAME AS TableName, IsDeleted=0, '<InsertSomeDescriptorHere>' AS [Source]--,t.TABLE_TYPE, c.*
            INTO dbo.AllTablesToDeleteFrom
            INNER JOIN information_schema.columns c ON c.TABLE_NAME = t.TABLE_NAME 
    WHERE c.COLUMN_NAME = '<column name>'
           AND c.TABLE_SCHEMA = 'dbo'
           AND c.TABLE_CATALOG = '<DB Name here>'
           AND t.TABLE_TYPE='Base table'
           --AND t.TABLE_NAME LIKE '<put filter here>'

            DECLARE @TableSelect NVARCHAR(1000)= '';
            DECLARE @Table NVARCHAR(1000)= '';
            DECLARE @IsDeleted INT= 0;
            DECLARE @NumRows INT = 1000000;
            DECLARE @Source NVARCHAR(50)='';

            WHILE ( @IsDeleted = 0 )
                --This grabs one table at a time to be deleted from. @TableSelect has the sql to execute. it is important to order by IsDeleted ASC
                --because it will pull tables to delete from by those that have a 0=IsDeleted first. Once the loop grabs a table with IsDeleted=1 then this will pop out of loop

                    SELECT TOP 1
                            @TableSelect = query,
                            @IsDeleted = IsDeleted,
                            @Table = TableName,
                    FROM    dbo.AllTablesToDeleteFrom a
                    WHERE a.[Source]='SomeDescriptorHere'--use only if needed
                    ORDER BY a.IsDeleted ASC;--this is required because only those records returned with IsDeleted=0 will run through loop

                    --SELECT  @Table; can add this in to  monitor what table is being deleted from

                    WHILE ( @NumRows = 1000000 )--only delete a million rows at a time?

                    EXEC sp_executesql @TableSelect;
                    SET @NumRows = @@ROWCOUNT;
                    --IF @NumRows = 1000000 --can do something here if needed
                    --One wants this loop to continue as long as a million rows is deleted. Once < 1 million rows is deleted it pops out of loop
                    --and grabs next table to delete
                    --    BEGIN
                    --SELECT  @NumRows;--can add this in to see current number of deleted records for table
                            INSERT  INTO dbo.DeleteFromAllTables
                                    ( tableName,
                            SELECT  @Table,
                     --   END; 

SET @NumRows = 1000000;

SET     a.IsDeleted = 1
FROM    dbo.AllTablesToDeleteFrom a
WHERE   a.TableName = @Table;
--flag this as deleted so you can move on to the next table to delete from


Difference between chr(13) and chr(10)

Chr(10) is the Line Feed character and Chr(13) is the Carriage Return character.

You probably won't notice a difference if you use only one or the other, but you might find yourself in a situation where the output doesn't show properly with only one or the other. So it's safer to include both.

Historically, Line Feed would move down a line but not return to column 1:


Similarly Carriage Return would return to column 1 but not move down a line:


Paste this into a text editor and then choose to "show all characters", and you'll see both characters present at the end of each line. Better safe than sorry.

C# equivalent of C++ vector, with contiguous memory?

use List<T>. Internally it uses arrays and arrays do use contiguous memory.

How to return only 1 row if multiple duplicate rows and still return rows that are not duplicates?

select * from temptable
where rnum --unique key

 SELECT RNUM --unique key
  FROM temptable
 WHERE (  HistoryStatus
) IN (SELECT                HistoryStatus

                             FROM temptable
                            GROUP BY                
                           HAVING COUNT(*) <= 1));

I have not tested this code. I have used similar code and it works. The syntax is in Oracle.

CSS3 Transform Skew One Side

you can make that using transform and transform origins.

Combining various transfroms gives similar result. I hope you find it helpful. :) See these examples for simpler transforms. this has left point :

div {    _x000D_
    width: 300px;_x000D_
    background-image: url('data:image/gif;base64,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');_x000D_
    -webkit-transform: perspective(300px) rotateX(-30deg);_x000D_
    -o-transform: perspective(300px) rotateX(-30deg);_x000D_
    -moz-transform: perspective(300px) rotateX(-30deg);_x000D_
    -webkit-transform-origin: 100% 50%;_x000D_
    -moz-transform-origin: 100% 50%;_x000D_
    -o-transform-origin: 100% 50%;_x000D_
    transform-origin: 100% 50%;_x000D_
    margin: 10px 90px;_x000D_

This has right skew point :

div {    _x000D_
    width: 300px;_x000D_
    background-image: url('data:image/gif;base64,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');_x000D_
    -webkit-transform: perspective(300px) rotateX(-30deg);_x000D_
    -o-transform: perspective(300px) rotateX(-30deg);_x000D_
    -moz-transform: perspective(300px) rotateX(-30deg);_x000D_
    -webkit-transform-origin: 0% 50%;_x000D_
    -moz-transform-origin: 0% 50%;_x000D_
    -o-transform-origin: 0% 50%;_x000D_
    transform-origin: 0% 50%;_x000D_
    margin: 10px 90px;_x000D_

what transform: 0% 50%; does is it sets the origin to vertical middle and horizontal left of the element. so the perspective is not visible at the left part of the image, so it looks flat. Perspective effect is there at the right part, so it looks slanted.

Uncaught TypeError: Cannot read property 'toLowerCase' of undefined

It fails "when trying to execute the function manually" because you have a different 'this'. This will refer not to the thing you have in mind when invoking the method manually, but something else, probably the window object, or whatever context object you have when invoking manually.

jQuery - Click event on <tr> elements with in a table and getting <td> element values

$(this).find('td') will give you an array of td's in the tr.

How to use the 'main' parameter in package.json?

As far as I know, it's the main entry point to your node package (library) for npm. It's needed if your npm project becomes a node package (library) which can be installed via npm by others.

Let's say you have a library with a build/, dist/, or lib/ folder. In this folder, you got the following compiled file for your library:


Then in your package.json, you tell npm how to access the library (node package):

  "name": "my-library-name",
  "main": "lib/bundle.js",

After installing the node package with npm to your JS project, you can import functionalities from your bundled bundle.js file:

import { add, subtract } from 'my-library-name';

This holds also true when using Code Splitting (e.g. Webpack) for your library. For instance, this webpack.config.js makes use of code splitting the project into multiple bundles instead of one.

module.exports = {
  entry: {
    main: './src/index.js',
    add: './src/add.js',
    subtract: './src/subtract.js',
  output: {
    path: `${__dirname}/lib`,
    filename: '[name].js',
    library: 'my-library-name',
    libraryTarget: 'umd',

Still, you would define one main entry point to your library in your package.json:

  "name": "my-library-name",
  "main": "lib/main.js",

Then when using the library, you can import your files from your main entry point:

import { add, subtract } from 'my-library-name';

However, you can also bypass the main entry point from the package.json and import the code splitted bundles:

import add from 'my-library-name/lib/add';
import subtract from 'my-library-name/lib/subtract';

After all, the main property in your package.json only points to your main entry point file of your library.

Android getResources().getDrawable() deprecated API 22

Build.VERSION_CODES.LOLLIPOP should now be changed to BuildVersionCodes.Lollipop i.e:

if (Build.VERSION.SdkInt >= BuildVersionCodes.Lollipop) {
    this.Control.Background = this.Resources.GetDrawable(Resource.Drawable.AddBorder, Context.Theme);
} else {
    this.Control.Background = this.Resources.GetDrawable(Resource.Drawable.AddBorder);

MySQL Select last 7 days

The WHERE clause is misplaced, it has to follow the table references and JOIN operations.

Something like this:

 FROM tartikel p1 
 JOIN tartikelpict p2 
   ON p1.kArtikel = p2.kArtikel 
  AND p2.nNr = 1
WHERE p1.dErstellt >= DATE(NOW()) - INTERVAL 7 DAY
ORDER BY p1.kArtikel DESC

EDIT (three plus years later)

The above essentially answers the question "I tried to add a WHERE clause to my query and now the query is returning an error, how do I fix it?"

As to a question about writing a condition that checks a date range of "last 7 days"...

That really depends on interpreting the specification, what the datatype of the column in the table is (DATE or DATETIME) and what data is available... what should be returned.

To summarize: the general approach is to identify a "start" for the date/datetime range, and "end" of that range, and reference those in a query. Let's consider something easier... all rows for "yesterday".

If our column is DATE type. Before we incorporate an expression into a query, we can test it in a simple SELECT


and verify the result returned is what we expect. Then we can use that same expression in a WHERE clause, comparing it to a DATE column like this:

 WHERE datecol = DATE(NOW()) + INTERVAL -1 DAY

For a DATETIME or TIMESTAMP column, we can use >= and < inequality comparisons to specify a range

 WHERE datetimecol >= DATE(NOW()) + INTERVAL -1 DAY
   AND datetimecol <  DATE(NOW()) + INTERVAL  0 DAY

For "last 7 days" we need to know if that mean from this point right now, back 7 days ... e.g. the last 7*24 hours , including the time component in the comparison, ...

 WHERE datetimecol >= NOW() + INTERVAL -7 DAY
   AND datetimecol <  NOW() + INTERVAL  0 DAY

the last seven complete days, not including today

 WHERE datetimecol >= DATE(NOW()) + INTERVAL -7 DAY
   AND datetimecol <  DATE(NOW()) + INTERVAL  0 DAY

or past six complete days plus so far today ...

 WHERE datetimecol >= DATE(NOW()) + INTERVAL -6 DAY
   AND datetimecol <  NOW()       + INTERVAL  0 DAY

I recommend testing the expressions on the right side in a SELECT statement, we can use a user-defined variable in place of NOW() for testing, not being tied to what NOW() returns so we can test borders, across week/month/year boundaries, and so on.

SET @clock = '2017-11-17 11:47:47' ;

     , DATE(@clock) + INTERVAL -7 DAY 
     , @clock + INTERVAL -6 DAY 

Once we have expressions that return values that work for "start" and "end" for our particular use case, what we mean by "last 7 days", we can use those expressions in range comparisons in the WHERE clause.

(Some developers prefer to use the DATE_ADD and DATE_SUB functions in place of the + INTERVAL val DAY/HOUR/MINUTE/MONTH/YEAR syntax.

And MySQL provides some convenient functions for working with DATE, DATETIME and TIMESTAMP datatypes... DATE, LAST_DAY,

Some developers prefer to calculate the start and end in other code, and supply string literals in the SQL query, such that the query submitted to the database is

  WHERE datetimecol >= '2017-11-10 00:00'
    AND datetimecol <  '2017-11-17 00:00'

And that approach works too. (My preference would be to explicitly cast those string literals into DATETIME, either with CAST, CONVERT or just the + INTERVAL trick...

  WHERE datetimecol >= '2017-11-10 00:00' + INTERVAL 0 SECOND
    AND datetimecol <  '2017-11-17 00:00' + INTERVAL 0 SECOND

The above all assumes we are storing "dates" in appropriate DATE, DATETIME and/or TIMESTAMP datatypes, and not storing them as strings in variety of formats e.g. 'dd/mm/yyyy', m/d/yyyy, julian dates, or in sporadically non-canonical formats, or as a number of seconds since the beginning of the epoch, this answer would need to be much longer.

Python executable not finding libpython shared library

I had the same problem and I solved it this way:

If you know where libpython resides at, I supposed it would be /usr/local/lib/ in your case, you can just create a symbolic link to it:

sudo ln -s /usr/local/lib/ /usr/lib/

Then try running ldd again and see if it worked.

TortoiseGit-git did not exit cleanly (exit code 1)

Actually, the easiest way to determine the error is to use 'Git Sync ...' then perform a pull/push from there - the error message is far more meaningful (i.e. there is one) and at least in my case, my -1 was due to a network path issue

How to Customize the time format for Python logging?

From the official documentation regarding the Formatter class:

The constructor takes two optional arguments: a message format string and a date format string.

So change

# create formatter
formatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s")


# create formatter
formatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s",
                              "%Y-%m-%d %H:%M:%S")

How to install Ruby 2.1.4 on Ubuntu 14.04

Use RVM (Ruby Version Manager) to install and manage any versions of Ruby. You can have multiple versions of Ruby installed on the machine and you can easily select the one you want.

To install RVM type into terminal:

\curl -sSL | bash -s stable

And let it work. After that you will have RVM along with Ruby installed.

Source: RVM Site

QED symbol in latex

You can use \blacksquare ¦:

When creating TeX, Knuth provided the symbol ¦ (solid black square), also called by mathematicians tombstone or Halmos symbol (after Paul Halmos, who pioneered its use as an equivalent of Q.E.D.). The tombstone is sometimes open: ? (hollow black square).

Print Html template in Angular 2 (ng-print in Angular 2)

Shortest solution to be assign the window to a typescript variable then call the print method on that, like below

in template file

<button ... (click)="window.print()" ...>Submit</button>

and, in typescript file

window: any;
constructor() {
  this.window = window;

Append values to query string

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

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

How to include duplicate keys in HashMap?

hashMaps can't have duplicate keys. That said, you can create a map with list values:

Map<Integer, List<String>>

However, using this approach will have performance implications.

How to create checkbox inside dropdown?

Multiple drop downs with checkbox's and jQuery.

<div id="list3" class="dropdown-check-list" tabindex="100">
<span class="anchor">Which development(s) are you interested in?</span>
  <ul class="items">
      <li><input id="answers_2529_the-lawns" name="answers[2529][answers][]" type="checkbox" value="The Lawns"/><label for="answers_2529_the-lawns">The Lawns</label></li>
      <li><input id="answers_2529_the-residence" name="answers[2529][answers][]" type="checkbox" value="The Residence"/><label for="answers_2529_the-residence">The Residence</label></li>

display: inline-block;
width: 100%;
.dropdown-check-list .anchor {
width: 98%;
position: relative;
cursor: pointer;
display: inline-block;
border:1px #ccc solid;
.dropdown-check-list .anchor:after {
position: absolute;
content: "";
border-left: 2px solid black;
border-top: 2px solid black;
padding: 5px;
right: 10px;
top: 20%;
-moz-transform: rotate(-135deg);
-ms-transform: rotate(-135deg);
-o-transform: rotate(-135deg);
-webkit-transform: rotate(-135deg);
transform: rotate(-135deg);
.dropdown-check-list .anchor:active:after {
right: 8px;
top: 21%;
.dropdown-check-list ul.items {
padding: 2px;
display: none;
margin: 0;
border: 1px solid #ccc;
border-top: none;
.dropdown-check-list ul.items li {
list-style: none;
.dropdown-check-list.visible .anchor {
color: #0094ff;
.dropdown-check-list.visible .items {
display: block;

jQuery(function ($) {
        var checkList = $('.dropdown-check-list');
        checkList.on('click', 'span.anchor', function(event){
            var element = $(this).parent();

            if ( element.hasClass('visible') )

Refresh a page using PHP

That is simply possible with header() in PHP:

header('Refresh: 1; url=index.php');

Best way to log POST data in Apache?

You can install mod_security and put in /etc/modsecurity/modsecurity.conf:

SecRuleEngine On
SecAuditEngine On
SecAuditLog /var/log/apache2/modsec_audit.log
SecRequestBodyAccess on
SecAuditLogParts ABIJDFHZ

Using PUT method in HTML form

Can I use "Put" method in html form to send data from HTML Form to server?

Yes you can, but keep in mind that it will not result in a PUT but a GET request. If you use an invalid value for the method attribute of the <form> tag, the browser will use the default value get.

HTML forms (up to HTML version 4 (, 5 Draft) and XHTML 1) only support GET and POST as HTTP request methods. A workaround for this is to tunnel other methods through POST by using a hidden form field which is read by the server and the request dispatched accordingly. XHTML 2.0 once planned to support GET, POST, PUT and DELETE for forms, but it's going into XHTML5 of HTML5, which does not plan to support PUT. [update to]

You can alternatively offer a form, but instead of submitting it, create and fire a XMLHttpRequest using the PUT method with JavaScript.

std::thread calling method of class

Not so hard:

#include <thread>

void Test::runMultiThread()
    std::thread t1(&Test::calculate, this,  0, 10);
    std::thread t2(&Test::calculate, this, 11, 20);

If the result of the computation is still needed, use a future instead:

#include <future>

void Test::runMultiThread()
     auto f1 = std::async(&Test::calculate, this,  0, 10);
     auto f2 = std::async(&Test::calculate, this, 11, 20);

     auto res1 = f1.get();
     auto res2 = f2.get();

Spring cron expression for every after 30 minutes

Graphically, the cron syntax for Quarz is (source):

+-------------------- second (0 - 59)
|  +----------------- minute (0 - 59)
|  |  +-------------- hour (0 - 23)
|  |  |  +----------- day of month (1 - 31)
|  |  |  |  +-------- month (1 - 12)
|  |  |  |  |  +----- day of week (0 - 6) (Sunday=0 or 7)
|  |  |  |  |  |  +-- year [optional]
|  |  |  |  |  |  |
*  *  *  *  *  *  * command to be executed 

So if you want to run a command every 30 minutes you can say either of these:

0 0/30 * * * * ?
0 0,30 * * * * ?

You can check crontab expressions using either of these:

  • — (disclaimer: I am not related to that page at all, only that I find it very useful). This page uses UNIX style of cron that does not have seconds in it, while Spring does as the first field.
  • Cron Expression Generator & Explainer - Quartz — cron formatter, allowing seconds also.

Pointers, smart pointers or shared pointers?

To avoid memory leaks you may use smart pointers whenever you can. There are basically 2 different types of smart pointers in C++

  • Reference counted (e.g. boost::shared_ptr / std::tr1:shared_ptr)
  • non reference counted (e.g. boost::scoped_ptr / std::auto_ptr)

The main difference is that reference counted smart pointers can be copied (and used in std:: containers) while scoped_ptr cannot. Non reference counted pointers have almost no overhead or no overhead at all. Reference counting always introduces some kind of overhead.

(I suggest to avoid auto_ptr, it has some serious flaws if used incorrectly)

How do I find the parent directory in C#?

No one has provided a solution that would work cross-form. I know it wasn't specifically asked but I am working in a linux environment where most of the solutions (as at the time I post this) would provide an error.

Hardcoding path separators (as well as other things) will give an error in anything but Windows systems.

In my original solution I used:

char filesep = Path.DirectorySeparatorChar;
string datapath = $"..{filesep}..{filesep}";

However after seeing some of the answers here I adjusted it to be:

string datapath = Directory.GetParent(Directory.GetParent(Directory.GetCurrentDirectory()).FullName).FullName; 

Calling a Fragment method from a parent Activity


My kubernetes pods keep crashing with "CrashLoopBackOff" but I can't find any log

In my case the problem was what Steve S. mentioned:

The pod is crashing because it starts up then immediately exits, thus Kubernetes restarts and the cycle continues.

Namely I had a Java application whose main threw an exception (and something overrode the default uncaught exception handler so that nothing was logged). The solution was to put the body of main into try { ... } catch and print out the exception. Thus I could find out what was wrong and fix it.

(Another cause could be something in the app calling System.exit; you could use a custom SecurityManager with an overridden checkExit to prevent (or log the caller of) exit; see

How to confirm RedHat Enterprise Linux version?

That's the RHEL release version.

You can see the kernel version by typing uname -r. It'll be 2.6.something.

WPF TabItem Header Styling

Try this style instead, it modifies the template itself. In there you can change everything you need to transparent:

<Style TargetType="{x:Type TabItem}">
  <Setter Property="Template">
      <ControlTemplate TargetType="{x:Type TabItem}">
          <Border Name="Border" Margin="0,0,0,0" Background="Transparent"
                  BorderBrush="Black" BorderThickness="1,1,1,1" CornerRadius="5">
            <ContentPresenter x:Name="ContentSite" VerticalAlignment="Center"
                              ContentSource="Header" Margin="12,2,12,2"
            <RotateTransform Angle="270" />
          <Trigger Property="IsSelected" Value="True">
            <Setter Property="Panel.ZIndex" Value="100" />
            <Setter TargetName="Border" Property="Background" Value="Red" />
            <Setter TargetName="Border" Property="BorderThickness" Value="1,1,1,0" />
          <Trigger Property="IsEnabled" Value="False">
            <Setter TargetName="Border" Property="Background" Value="DarkRed" />
            <Setter TargetName="Border" Property="BorderBrush" Value="Black" />
            <Setter Property="Foreground" Value="DarkGray" />

Sending an Intent to browser to open specific URL

To open a URL/website you do the following:

String url = "";
Intent i = new Intent(Intent.ACTION_VIEW);

Here's the documentation of Intent.ACTION_VIEW.

Source: Opening a URL in Android's web browser from within application

Can't subtract offset-naive and offset-aware datetimes

The psycopg2 module has its own timezone definitions, so I ended up writing my own wrapper around utcnow:

def pg_utcnow():
    import psycopg2
    return datetime.utcnow().replace(, name=None))

and just use pg_utcnow whenever you need the current time to compare against a PostgreSQL timestamptz

Position a div container on the right side

Just wanna update this for beginners now you should definitly use flexbox to do that, it's more appropriate and work for responsive try this :




<div id="wrapper">
    <div id="c1">con1</div>
    <div id="c2">con2</div>

Cannot ping AWS EC2 instance

Those who are new to aws ec2 and wants to access the instance from SSH, Broswer, Ping from system then below is the inbound rule for these:-

enter image description here

What is the difference between a deep copy and a shallow copy?

I came to understand from the following lines.

Shallow copy copies an object value type(int, float, bool) fields in to target object and object's reference types(string, class etc) are copied as references in target object. In this target reference types will be pointing to the memory location of source object.

Deep copy copies an object's value and reference types into a complete new copy of the target objects. This means both the value types and reference types will be allocated a new memory locations.

How do I set the background color of my main screen in Flutter?

and it's another approach to change the color of background:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
Widget build(BuildContext context) {
return MaterialApp(home: Scaffold(backgroundColor:,),);

How do you replace all the occurrences of a certain character in a string?

I would use the translate method without translation table. It deletes the letters in second argument in recent Python versions.

def remove_chars(line):
    return line[:7]+[line7]+line[8:]

line= ['ad','da','sdf','asd',
print line[7]
line = remove_chars(line)
print line[7]

Using "Object.create" instead of "new"

You could make the init method return this, and then chain the calls together, like this:

var userB = {
    init: function(nameParam) { = MY_GLOBAL.nextId(); = nameParam;
        return this;
    sayHello: function() {
        console.log('Hello '+;

var bob = Object.create(userB).init('Bob');

Pandas groupby: How to get a union of strings

You could try this:


Footnotes for tables in LaTeX

Use minipage environment. Here is an example:

    A & 1 & 2 \footnote{This is a footnote.} \\
    B & 2 & 1 \\
    C & 3 & 3 \\

Confusing "duplicate identifier" Typescript error message

I had this issue caused by having an unexpected folder on disk (jspm_packages, no longer being used) which was not tracked by source control (and hidden from my IDE). This had a duplicate install of TypeScript in it, which caused the issues.

Bit of an edge case but leaving an answer here just in case someone else is hunting for this solution.

background:none vs background:transparent what is the difference?

To complement the other answers: if you want to reset all background properties to their initial value (which includes background-color: transparent and background-image: none) without explicitly specifying any value such as transparent or none, you can do so by writing:

background: initial;

Print second last column/field in awk

If you have many columns and want to print all but not the three cloumns in the last, then this might help

awk '{ $NF="";$(NF-1)="";$(NF-2)="" ; print $0 }'

Difference between VARCHAR and TEXT in MySQL



  • fixed max size of 65535 characters (you cannot limit the max size)
  • takes 2 + c bytes of disk space, where c is the length of the stored string.
  • cannot be (fully) part of an index. One would need to specify a prefix length.


  • variable max size of M characters
  • M needs to be between 1 and 65535
  • takes 1 + c bytes (for M ≤ 255) or 2 + c (for 256 ≤ M ≤ 65535) bytes of disk space where c is the length of the stored string
  • can be part of an index

More Details

TEXT has a fixed max size of 2¹6-1 = 65535 characters.
VARCHAR has a variable max size M up to M = 2¹6-1.
So you cannot choose the size of TEXT but you can for a VARCHAR.

The other difference is, that you cannot put an index (except for a fulltext index) on a TEXT column.
So if you want to have an index on the column, you have to use VARCHAR. But notice that the length of an index is also limited, so if your VARCHAR column is too long you have to use only the first few characters of the VARCHAR column in your index (See the documentation for CREATE INDEX).

But you also want to use VARCHAR, if you know that the maximum length of the possible input string is only M, e.g. a phone number or a name or something like this. Then you can use VARCHAR(30) instead of TINYTEXT or TEXT and if someone tries to save the text of all three "Lord of the Ring" books in your phone number column you only store the first 30 characters :)

Edit: If the text you want to store in the database is longer than 65535 characters, you have to choose MEDIUMTEXT or LONGTEXT, but be careful: MEDIUMTEXT stores strings up to 16 MB, LONGTEXT up to 4 GB. If you use LONGTEXT and get the data via PHP (at least if you use mysqli without store_result), you maybe get a memory allocation error, because PHP tries to allocate 4 GB of memory to be sure the whole string can be buffered. This maybe also happens in other languages than PHP.

However, you should always check the input (Is it too long? Does it contain strange code?) before storing it in the database.

Notice: For both types, the required disk space depends only on the length of the stored string and not on the maximum length.
E.g. if you use the charset latin1 and store the text "Test" in VARCHAR(30), VARCHAR(100) and TINYTEXT, it always requires 5 bytes (1 byte to store the length of the string and 1 byte for each character). If you store the same text in a VARCHAR(2000) or a TEXT column, it would also require the same space, but, in this case, it would be 6 bytes (2 bytes to store the string length and 1 byte for each character).

For more information have a look at the documentation.

Finally, I want to add a notice, that both, TEXT and VARCHAR are variable length data types, and so they most likely minimize the space you need to store the data. But this comes with a trade-off for performance. If you need better performance, you have to use a fixed length type like CHAR. You can read more about this here.

addClass and removeClass in jQuery - not removing class

I think that the problem is in the nesting of the elements. Once you attach an event to the outer element the clicks on the inner elements are actually firing the same click event for the outer element. So, you actually never go to the second state. What you can do is to check the clicked element. And if it is the close button then to avoid the class changing. Here is my solution:

var element = $(".clickable");
var closeButton = element.find(".close_button");
var onElementClick = function(e) {
    if( !== closeButton[0]) {
        closeButton.on("click", onCloseClick);
var onCloseClick = function() {
    element.on("click", onElementClick);
element.on("click", onElementClick);

In addition I'm adding and removing event handlers.

JSFiddle ->

How to display custom view in ActionBar?

I struggled with this myself, and tried Tomik's answer. However, this didn't made the layout to full available width on start, only when you add something to the view.

You'll need to set the LayoutParams.FILL_PARENT when adding the view:

//I'm using actionbarsherlock, but it's the same.
LayoutParams layout = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
getSupportActionBar().setCustomView(overlay, layout); 

This way it completely fills the available space. (You may need to use Tomik's solution too).

How to replace comma (,) with a dot (.) using java

For the current information you are giving, it will be enought with this simple regex to do the replacement:

str.replaceAll(",", ".");

Access denied for user 'root'@'localhost' while attempting to grant privileges. How do I grant privileges?

I also had the same problem with this but on Windows after upgrading to MySQL 5.5 from MySQL 5.1. I already tried changing, creating, and resetting password mentioned in here, here, here, and here, no clue. I still get the same error:

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

I'm able to connect normally, show all databases, do selects and inserts, create and add users, and but when it comes to GRANT, I'm screwed up. Those access denied error shows up again.

I managed to solve this problem by fixing the privileges by the following command on the MySQL server bin/ directory as mentioned in here:

C:\MySQL Server 5.5\bin> mysql_upgrade

Then, the problem gone away. I hope this solution works on Linux too since usually MySQL provide the same command both on Linux and Windows.

Jquery array.push() not working

another workaround:

var myarray = [];
$("#test").click(function() {

i wanted to add all checked checkbox to array. so example, if .each is used:

var vpp = [];
var incr=0;
$('.prsn').each(function(idx) {
   if (this.checked) {
       var p=$('.pp').eq(idx).val();
//do what ever with vpp array;

How do I split a string on a delimiter in Bash?

Two bourne-ish alternatives where neither require bash arrays:

Case 1: Keep it nice and simple: Use a NewLine as the Record-Separator... eg.

IN="[email protected]
[email protected]"

while read i; do
  # process "$i" ... eg.
    echo "[email:$i]"
done <<< "$IN"

Note: in this first case no sub-process is forked to assist with list manipulation.

Idea: Maybe it is worth using NL extensively internally, and only converting to a different RS when generating the final result externally.

Case 2: Using a ";" as a record separator... eg.

" IRS=";" ORS=";"

conv_IRS() {
  exec tr "$1" "$NL"

conv_ORS() {
  exec tr "$NL" "$1"

IN="[email protected];[email protected]"
IN="$(conv_IRS ";" <<< "$IN")"

while read i; do
  # process "$i" ... eg.
    echo -n "[email:$i]$ORS"
done <<< "$IN"

In both cases a sub-list can be composed within the loop is persistent after the loop has completed. This is useful when manipulating lists in memory, instead storing lists in files. {p.s. keep calm and carry on B-) }

How do I delete specific characters from a particular String in Java?

You can't modify a String in Java. They are immutable. All you can do is create a new string that is substring of the old string, minus the last character.

In some cases a StringBuffer might help you instead.

JavaScript: Difference between .forEach() and .map()

¦                ¦ foreach                             ¦ map                                   ¦
¦ Functionality  ¦ Performs given operation on each    ¦ Performs given "transformation" on    ¦
¦                ¦ element of the array                ¦ "copy" of each element                ¦
¦ Return value   ¦ Returns undefined                   ¦ Returns new array with tranformed     ¦
¦                ¦                                     ¦ elements leaving back original array  ¦
¦                ¦                                     ¦ unchanged                             ¦
¦ Preferrable    ¦ Performing non—transformation like  ¦ Obtaining array containing output of  ¦
¦ usage scenario ¦ processing on each element.         ¦ some processing done on each element  ¦
¦ and example    ¦                                     ¦ of the array.                         ¦
¦                ¦ For example, saving all elements in ¦                                       ¦
¦                ¦ the database                        ¦ For example, obtaining array of       ¦
¦                ¦                                     ¦ lengths of each string in the         ¦
¦                ¦                                     ¦ array                                 ¦

How to convert a String to JsonObject using gson library

You don't need to use JsonObject. You should be using Gson to convert to/from JSON strings and your own Java objects.

See the Gson User Guide:


Gson gson = new Gson();
gson.toJson(1);                   // prints 1
gson.toJson("abcd");              // prints "abcd"
gson.toJson(new Long(10));        // prints 10
int[] values = { 1 };
gson.toJson(values);              // prints [1]


int one = gson.fromJson("1", int.class);
Integer one = gson.fromJson("1", Integer.class);
Long one = gson.fromJson("1", Long.class);
Boolean false = gson.fromJson("false", Boolean.class);
String str = gson.fromJson("\"abc\"", String.class);
String anotherStr = gson.fromJson("[\"abc\"]", String.class)

DB2 SQL error: SQLCODE: -206, SQLSTATE: 42703

That only means that an undefined column or parameter name was detected. The errror that DB2 gives should point what that may be:


Double check your table definition. Maybe you just missed adding something.

I also tried google-ing this problem and saw this:

Column standard deviation R

The general idea is to sweep the function across. You have many options, one is apply():

R> set.seed(42)
R> M <- matrix(rnorm(40),ncol=4)
R> apply(M, 2, sd)
[1] 0.835449 1.630584 1.156058 1.115269

Change Spinner dropdown icon

For this you can use .9 Patch Image and just simply set it in to background.


Here i'll give you .9patch image. try with this.

enter image description here enter image description here

Right click on image and click Save Image as

set image name like this : anyname.9.png and hit save.

Enjoy.. Happy Coading. :)

Initialization of all elements of an array to one default value in C++?

Using the syntax that you used,

int array[100] = {-1};

says "set the first element to -1 and the rest to 0" since all omitted elements are set to 0.

In C++, to set them all to -1, you can use something like std::fill_n (from <algorithm>):

std::fill_n(array, 100, -1);

In portable C, you have to roll your own loop. There are compiler-extensions or you can depend on implementation-defined behavior as a shortcut if that's acceptable.

What does it mean with bug report captured in android tablet?

It's because you have turned on USB debugging in Developer Options. You can create a bug report by holding the power + both volume up and down.

Edit: This is what the forums say:

By pressing Volume up + Volume down + power button, you will feel a vibration after a second or so, that's when the bug reporting initiated.

To disable:

/system/bin/ must be deleted/renamed.

There should be a folder on your SD card called "bug reports".

Have a look at this thread:

And this one:

How do you detect the clearing of a "search" HTML5 input?

Bind search-event the search box as given below-

$('input[type=search]').on('search', function () {
    // search logic here
    // this function will be executed on click of X (clear button)

Xpath: select div that contains class AND whose specific child element contains text

You could use the xpath :

//div[@class="measure-tab" and .//span[contains(., "someText")]]

Input :

<div class="measure-tab">
  <td> someText</td>
<div class="measure-tab">

Output :

    Element='<div class="measure-tab">

How to print to console in pytest?

By default, py.test captures the result of standard out so that it can control how it prints it out. If it didn't do this, it would spew out a lot of text without the context of what test printed that text.

However, if a test fails, it will include a section in the resulting report that shows what was printed to standard out in that particular test.

For example,

def test_good():
    for i in range(1000):

def test_bad():
    print('this should fail!')
    assert False

Results in the following output:

>>> py.test
============================= test session starts ==============================
platform darwin -- Python 2.7.6 -- py-1.4.20 -- pytest-2.5.2
plugins: cache, cov, pep8, xdist
collected 2 items .F

=================================== FAILURES ===================================
___________________________________ test_bad ___________________________________

    def test_bad():
        print('this should fail!')
>       assert False
E       assert False AssertionError
------------------------------- Captured stdout --------------------------------
this should fail!
====================== 1 failed, 1 passed in 0.04 seconds ======================

Note the Captured stdout section.

If you would like to see print statements as they are executed, you can pass the -s flag to py.test. However, note that this can sometimes be difficult to parse.

>>> py.test -s
============================= test session starts ==============================
platform darwin -- Python 2.7.6 -- py-1.4.20 -- pytest-2.5.2
plugins: cache, cov, pep8, xdist
collected 2 items 0
... and so on ...
.this should fail!

=================================== FAILURES ===================================
___________________________________ test_bad ___________________________________

    def test_bad():
        print('this should fail!')
>       assert False
E       assert False AssertionError
====================== 1 failed, 1 passed in 0.02 seconds ======================

curl: (60) SSL certificate problem: unable to get local issuer certificate

Had this problem after install Git Extensions v3.48. Tried to install mysysgit again but same problem. At the end, had to disable (please consider security implications!) Git SSL verification with:

git config --global http.sslVerify false

but if you have a domain certificate better add it to (Win7)

C:\Program Files (x86)\Git\bin\curl-ca-bundle.crt

TSQL CASE with if comparison in SELECT statement

You can try with this:

WITH CTE_A As (SELECT COUNT(*) as articleNumber,A.UserID  as UserID FROM Articles A
           Inner Join Users U
           on  A.userId = U.userId 
           Group By A.userId , U.userId   ),

B as (Select us.registrationDate,

         WHEN CTE_A.articleNumber < 2 THEN 'Ama'
         WHEN CTE_A.articleNumber < 5 THEN 'SemiAma' 
         WHEN CTE_A.articleNumber < 7 THEN 'Good'  
         WHEN CTE_A.articleNumber < 9 THEN 'Better' 
         WHEN CTE_A.articleNumber < 12 THEN 'Best'
         ELSE 'Outstanding'
         END as Ranking,
         us.hobbies, etc...
         FROM USERS Us Inner Join CTE_A 
         on CTE_A.UserID=us.UserID)

Select * from B

How do I append text to a file?

Other possible way is:

echo "text" | tee -a filename >/dev/null

The -a will append at the end of the file.

If needing sudo, use:

echo "text" | sudo tee -a filename >/dev/null

How do I import a .bak file into Microsoft SQL Server 2012?

Not sure why they removed the option to just right click on the database and restore like you could in SQL Server Management Studio 2008 and earlier, but as mentioned above you can restore from a .BAK file with:


But you will want WITH REPLACE instead of WITH RESTORE if your moving it from one server to another.

How to convert xml into array in php?


  * convert xml string to php array - useful to get a serializable value
  * @param string $xmlstr
  * @return array
  * @author Adrien aka Gaarf & contributors
  * @see
function xmlstr_to_array($xmlstr) {
  $doc = new DOMDocument();
  $root = $doc->documentElement;
  $output = domnode_to_array($root);
  $output['@root'] = $root->tagName;
  return $output;
function domnode_to_array($node) {
  $output = array();
  switch ($node->nodeType) {
    case XML_TEXT_NODE:
      $output = trim($node->textContent);
      for ($i=0, $m=$node->childNodes->length; $i<$m; $i++) {
        $child = $node->childNodes->item($i);
        $v = domnode_to_array($child);
        if(isset($child->tagName)) {
          $t = $child->tagName;
          if(!isset($output[$t])) {
            $output[$t] = array();
          $output[$t][] = $v;
        elseif($v || $v === '0') {
          $output = (string) $v;
      if($node->attributes->length && !is_array($output)) { //Has attributes but isn't an array
        $output = array('@content'=>$output); //Change output into an array.
      if(is_array($output)) {
        if($node->attributes->length) {
          $a = array();
          foreach($node->attributes as $attrName => $attrNode) {
            $a[$attrName] = (string) $attrNode->value;
          $output['@attributes'] = $a;
        foreach ($output as $t => $v) {
          if(is_array($v) && count($v)==1 && $t!='@attributes') {
            $output[$t] = $v[0];
  return $output;

How to serve static files in Flask

One of the simple way to do. Cheers!

from flask import Flask, render_template
app = Flask(__name__)

def index():
   return render_template("index.html")

if __name__ == '__main__': = True)

Now create folder name called templates. Add your index.html file inside of templates folder


<!DOCTYPE html>
    <title>Python Web Application</title>
            Welcomes You!!

Project Structure

How to set environment variables in PyCharm?

You can set environmental variables in Pycharm's run configurations menu.

  1. Open the Run Configuration selector in the top-right and cick Edit Configurations...

    Edit Configurations...

  2. Find Environmental variables and click ...

    Environmental variables

  3. Add or change variables, then click OK

    Editing environmental variables

You can access your environmental variables with os.environ

import os

Centering a background image, using CSS

The only thing that worked for me is..

margin: 0 auto

How to generate keyboard events?

It can be done using ctypes:

import ctypes
from ctypes import wintypes
import time

user32 = ctypes.WinDLL('user32', use_last_error=True)


KEYEVENTF_KEYUP       = 0x0002


VK_TAB  = 0x09
VK_MENU = 0x12

# C struct definitions

wintypes.ULONG_PTR = wintypes.WPARAM

class MOUSEINPUT(ctypes.Structure):
    _fields_ = (("dx",          wintypes.LONG),
                ("dy",          wintypes.LONG),
                ("mouseData",   wintypes.DWORD),
                ("dwFlags",     wintypes.DWORD),
                ("time",        wintypes.DWORD),
                ("dwExtraInfo", wintypes.ULONG_PTR))

class KEYBDINPUT(ctypes.Structure):
    _fields_ = (("wVk",         wintypes.WORD),
                ("wScan",       wintypes.WORD),
                ("dwFlags",     wintypes.DWORD),
                ("time",        wintypes.DWORD),
                ("dwExtraInfo", wintypes.ULONG_PTR))

    def __init__(self, *args, **kwds):
        super(KEYBDINPUT, self).__init__(*args, **kwds)
        # some programs use the scan code even if KEYEVENTF_SCANCODE
        # isn't set in dwFflags, so attempt to map the correct code.
        if not self.dwFlags & KEYEVENTF_UNICODE:
            self.wScan = user32.MapVirtualKeyExW(self.wVk,
                                                 MAPVK_VK_TO_VSC, 0)

class HARDWAREINPUT(ctypes.Structure):
    _fields_ = (("uMsg",    wintypes.DWORD),
                ("wParamL", wintypes.WORD),
                ("wParamH", wintypes.WORD))

class INPUT(ctypes.Structure):
    class _INPUT(ctypes.Union):
        _fields_ = (("ki", KEYBDINPUT),
                    ("mi", MOUSEINPUT),
                    ("hi", HARDWAREINPUT))
    _anonymous_ = ("_input",)
    _fields_ = (("type",   wintypes.DWORD),
                ("_input", _INPUT))


def _check_count(result, func, args):
    if result == 0:
        raise ctypes.WinError(ctypes.get_last_error())
    return args

user32.SendInput.errcheck = _check_count
user32.SendInput.argtypes = (wintypes.UINT, # nInputs
                             LPINPUT,       # pInputs
                             ctypes.c_int)  # cbSize

# Functions

def PressKey(hexKeyCode):
    user32.SendInput(1, ctypes.byref(x), ctypes.sizeof(x))

def ReleaseKey(hexKeyCode):
    user32.SendInput(1, ctypes.byref(x), ctypes.sizeof(x))

def AltTab():
    """Press Alt+Tab and hold Alt key for 2 seconds
    in order to see the overlay.
    PressKey(VK_MENU)   # Alt
    PressKey(VK_TAB)    # Tab
    ReleaseKey(VK_TAB)  # Tab~
    ReleaseKey(VK_MENU) # Alt~

if __name__ == "__main__":

hexKeyCode is the virtual keyboard mapping as defined by the Windows API. The list of codes is available on MSDN: Virtual-Key Codes (Windows)

How do I install the babel-polyfill library?

First off, the obvious answer that no one has provided, you need to install Babel into your application:

npm install babel --save

(or babel-core if you instead want to require('babel-core/polyfill')).

Aside from that, I have a grunt task to transpile my es6 and jsx as a build step (i.e. I don't want to use babel/register, which is why I am trying to use babel/polyfill directly in the first place), so I'd like to put more emphasis on this part of @ssube's answer:

Make sure you require it at the entry-point to your application, before anything else is called

I ran into some weird issue where I was trying to require babel/polyfill from some shared environment startup file and I got the error the user referenced - I think it might have had something to do with how babel orders imports versus requires but I'm unable to reproduce now. Anyway, moving import 'babel/polyfill' as the first line in both my client and server startup scripts fixed the problem.

Note that if you instead want to use require('babel/polyfill') I would make sure all your other module loader statements are also requires and not use imports - avoid mixing the two. In other words, if you have any import statements in your startup script, make import babel/polyfill the first line in your script rather than require('babel/polyfill').

How to take a first character from the string

Try this..

Dim S As String
Dim answer As Char
answer = S.Substring(0, 1)

Clean out Eclipse workspace metadata

One of the things that you might want to try out is starting eclipse with the -clean option. If you have chosen to have eclipse use the same workspace every time then there is nothing else you need to do after that. With that option in place the workspace should be cleaned out.

However, if you don't have a default workspace chosen, when opening up eclipse you will be prompted to choose the workspace. At this point, choose the workspace you want cleaned up.

See "How to run eclipse in clean mode" and "Keeping Eclipse running clean" for more details.

Get Hard disk serial Number

Below a fully functional method to get hard disk serial number:

public string GetHardDiskSerialNo()
        ManagementClass mangnmt = new ManagementClass("Win32_LogicalDisk");
        ManagementObjectCollection mcol = mangnmt.GetInstances();
        string result = "";
        foreach (ManagementObject strt in mcol)
            result += Convert.ToString(strt["VolumeSerialNumber"]);
        return result;

SQL query to get the deadlocks in SQL SERVER 2008

You can use a deadlock graph and gather the information you require from the log file.

The only other way I could suggest is digging through the information by using EXEC SP_LOCK (Soon to be deprecated), EXEC SP_WHO2 or the sys.dm_tran_locks table.

SELECT  L.request_session_id AS SPID, 
    DB_NAME(L.resource_database_id) AS DatabaseName,
    O.Name AS LockedObjectName, 
    P.object_id AS LockedObjectId, 
    L.resource_type AS LockedResource, 
    L.request_mode AS LockType,
    ST.text AS SqlStatementText,        
    ES.login_name AS LoginName,
    ES.host_name AS HostName,
    TST.is_user_transaction as IsUserTransaction, as TransactionName,
    CN.auth_scheme as AuthenticationMethod
FROM    sys.dm_tran_locks L
    JOIN sys.partitions P ON P.hobt_id = L.resource_associated_entity_id
    JOIN sys.objects O ON O.object_id = P.object_id
    JOIN sys.dm_exec_sessions ES ON ES.session_id = L.request_session_id
    JOIN sys.dm_tran_session_transactions TST ON ES.session_id = TST.session_id
    JOIN sys.dm_tran_active_transactions AT ON TST.transaction_id = AT.transaction_id
    JOIN sys.dm_exec_connections CN ON CN.session_id = ES.session_id
    CROSS APPLY sys.dm_exec_sql_text(CN.most_recent_sql_handle) AS ST
WHERE   resource_database_id = db_id()
ORDER BY L.request_session_id

PIG how to count a number of rows in alias

Arnon Rotem-Gal-Oz already answered this question a while ago, but I thought some may like this slightly more concise version.

LOGS = LOAD 'log';

PowerShell script to check the status of a URL

You can try this:

function Get-UrlStatusCode([string] $Url)
        (Invoke-WebRequest -Uri $Url -UseBasicParsing -DisableKeepAlive).StatusCode
    catch [Net.WebException]

$statusCode = Get-UrlStatusCode ''

how to implement a pop up dialog box in iOS

For Swift 3 & Swift 4 :

Since UIAlertView is deprecated, there is the good way for display Alert on Swift 3

let alertController = UIAlertController(title: NSLocalizedString("No network connection",comment:""), message: NSLocalizedString("connected to the internet to use this app.",comment:""), preferredStyle: .alert)
let defaultAction = UIAlertAction(title:     NSLocalizedString("Ok", comment: ""), style: .default, handler: { (pAlert) in
                //Do whatever you want here
self.present(alertController, animated: true, completion: nil)

Deprecated :

This is the swift version inspired by the checked response :

Display AlertView :

   let alert = UIAlertView(title: "No network connection", 
                           message: "You must be connected to the internet to use this app.", delegate: nil, cancelButtonTitle: "Ok")
    alert.delegate = self

Add the delegate to your view controller :

class AgendaViewController: UIViewController, UIAlertViewDelegate

When user click on button, this code will be executed :

func alertView(alertView: UIAlertView, clickedButtonAtIndex buttonIndex: Int) {