Programs & Examples On #Python egg cache

milliseconds to days

If you don't have another time interval bigger than days:

int days = (int) (milliseconds / (1000*60*60*24));

If you have weeks too:

int days = (int) ((milliseconds / (1000*60*60*24)) % 7);
int weeks = (int) (milliseconds / (1000*60*60*24*7));

It's probably best to avoid using months and years if possible, as they don't have a well-defined fixed length. Strictly speaking neither do days: daylight saving means that days can have a length that is not 24 hours.

No such keg: /usr/local/Cellar/git

Os X Mojave 10.14 has:

Error: The Command Line Tools header package must be installed on Mojave.

Solution. Go to


location and install the package manually. And brew will start working and we can run:

brew uninstall --force git
brew cleanup --force -s git
brew prune
brew install git

Define an <img>'s src attribute in CSS

No. The closest you can get is setting a background image:

<div id="myimage"></div>

#myimage {
  width: 20px;
  height: 20px;
  background: white url(myimage.gif) no-repeat;

Inline IF Statement in C#

The literal answer is:

return (value == 1 ? Periods.VariablePeriods : Periods.FixedPeriods);

Note that the inline if statement, just like an if statement, only checks for true or false. If (value == 1) evaluates to false, it might not necessarily mean that value == 2. Therefore it would be safer like this:

return (value == 1
    ? Periods.VariablePeriods
    : (value == 2
        ? Periods.FixedPeriods
        : Periods.Unknown));

If you add more values an inline if will become unreadable and a switch would be preferred:

switch (value)
case 1:
    return Periods.VariablePeriods;
case 2:
    return Periods.FixedPeriods;

The good thing about enums is that they have a value, so you can use the values for the mapping, as user854301 suggested. This way you can prevent unnecessary branches thus making the code more readable and extensible.

Limit the size of a file upload (html input element)

const input = document.getElementById('input')_x000D_
input.addEventListener('change', (event) => {_x000D_
  const target = event.target_x000D_
   if (target.files && target.files[0]) {_x000D_
      /*Maximum allowed size in bytes_x000D_
        5MB Example_x000D_
        Change first operand(multiplier) for your needs*/_x000D_
      const maxAllowedSize = 5 * 1024 * 1024;_x000D_
      if (target.files[0].size > maxAllowedSize) {_x000D_
       // Here you can ask your users to load correct file_x000D_
        target.value = ''_x000D_
<input type="file" id="input" />

Decode HTML entities in Python string?

Beautiful Soup 4 allows you to set a formatter to your output

If you pass in formatter=None, Beautiful Soup will not modify strings at all on output. This is the fastest option, but it may lead to Beautiful Soup generating invalid HTML/XML, as in these examples:

# <html>
#  <body>
#   <p>
#    Il a dit <<Sacré bleu!>>
#   </p>
#  </body>
# </html>

link_soup = BeautifulSoup('<a href="">A link</a>')
# <a href="">A link</a>

How do I parse JSON into an int?

At first, you create a BufferedReader on a FileReader to the file.

Then, you create a new `JSONParser()´ object that parses the content read from the file.

You cast the parsed Object to a JSONObject and get the id field.

FileReader file=new FileReader("1.json");
BufferedReader write=new BufferedReader(file);
Object obj=new JSONParser().parse(write);
JSONObject jo = (JSONObject) obj;
long id=(long)jo.get("id");

Get human readable version of file size?

This feature if available in Boltons which is a very handy library to have for most projects.

>>> bytes2human(128991)
>>> bytes2human(100001221)
>>> bytes2human(0, 2)

how to prevent this error : Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in ... on line 11

You don't need to prevent this error message!
Error messages are your friends!
Without error message you'd never know what is happened.
It's all right! Any working code supposed to throw out error messages.

Though error messages needs proper handling. Usually you don't have to to take any special actions to avoid such an error messages. Just leave your code intact. But if you don't want this error message to be shown to the user, just turn it off. Not error message itself but daislaying it to the user.


or even better at .htaccess/php.ini level
And user will never see any error messages. While you will be able still see it in the error log.
Please note that error_reporting should be at max in both cases.

To prevent this message you can check mysql_query result and run fetch_assoc only on success.
But usually nobody uses it as it may require too many nested if's.
But there can be solution too - exceptions!

But it is still not necessary. You can leave your code as is, because it is supposed to work without errors when done.

Using return is another method to avoid nested error messages. Here is a snippet from my database handling function:

  $res = mysql_query($query);
  if (!$res) {
    trigger_error("dbget: ".mysql_error()." in ".$query);
    return false;
  if (!mysql_num_rows($res)) return NULL;

  //fetching goes here
  //if there was no errors only

Does WhatsApp offer an open API?

1) It looks possible. This info on Github describes how to create a java program to send a message using the whatsapp encryption protocol from WhisperSystems.

2) No. See the whatsapp security white paper.

3) See #1.

Volley - POST/GET parameters

For Future Readers

I love to work with Volley. To save development time i tried to write small handy library Gloxey Netwok Manager to setup Volley with my project. It includes JSON parser and different other methods that helps to check network availability.

Use ConnectionManager.class in which different methods for Volley String and Volley JSON request are available. You can make requests of GET, PUT, POST, DELETE with or without header. You can read full documentation here.

Just put this line in your gradle file.

  dependencies { 

       compile 'io.gloxey.gnm:network-manager:1.0.1'

Volley StringRequest

Method GET (without header)

    ConnectionManager.volleyStringRequest(context, isDialog, progressDialogView, requestURL, volleyResponseInterface);

How to use?

     Configuration                Description

     Context                      Context 
     isDialog                     If true dialog will appear, otherwise not.
     progressView                 For custom progress view supply your progress view id and make isDialog true. otherwise pass null. 
     requestURL                   Pass your API URL.  
     volleyResponseInterface      Callback for response.  


    ConnectionManager.volleyStringRequest(this, false, null, "url", new VolleyResponse() {
    public void onResponse(String _response) {

         * Handle Response

     public void onErrorResponse(VolleyError error) {

         * handle Volley Error

    public void isNetwork(boolean connected) {

         * True if internet is connected otherwise false

Volley StringRequest

Method POST/PUT/DELETE (without header)

    ConnectionManager.volleyStringRequest(context, isDialog, progressDialogView, requestURL, requestMethod, params, volleyResponseInterface);


Use Method : Request.Method.POST

Your params : 

HashMap<String, String> params = new HashMap<>();
params.put("param 1", "value");
params.put("param 2", "value");

ConnectionManager.volleyStringRequest(this, true, null, "url", Request.Method.POST, params, new VolleyResponse() {
    public void onResponse(String _response) {

         * Handle Response

    public void onErrorResponse(VolleyError error) {

         * handle Volley Error

    public void isNetwork(boolean connected) {

         * True if internet is connected otherwise false


Gloxey JSON Parser

Feel free to use gloxey json parser to parse your api response.

  YourModel yourModel = GloxeyJsonParser.getInstance().parse(stringResponse, YourModel.class);


ConnectionManager.volleyStringRequest(this, false, null, "url", new VolleyResponse() {
    public void onResponse(String _response) {

         * Handle Response

         try {

          YourModel yourModel = GloxeyJsonParser.getInstance().parse(_response, YourModel.class);

            } catch (Exception e) {


     public void onErrorResponse(VolleyError error) {

         * handle Volley Error
         if (error instanceof TimeoutError || error instanceof NoConnectionError) {

                showSnackBar(parentLayout, getString(R.string.internet_not_found), getString(R.string.retry), new View.OnClickListener() {
                    public void onClick(View view) {

                     //handle retry button


            } else if (error instanceof AuthFailureError) {
            } else if (error instanceof ServerError) {
            } else if (error instanceof NetworkError) {
            } else if (error instanceof ParseError) {


    public void isNetwork(boolean connected) {

         * True if internet is connected otherwise false
          if (!connected) {
                showSnackBar(parentLayout, getString(R.string.internet_not_found), getString(R.string.retry), new View.OnClickListener() {
                    public void onClick(View view) {
                        //Handle retry button

     public void showSnackBar(View view, String message) {
            Snackbar.make(view, message, Snackbar.LENGTH_LONG).show();

     public void showSnackBar(View view, String message, String actionText, View.OnClickListener onClickListener) {
            Snackbar.make(view, message, Snackbar.LENGTH_LONG).setAction(actionText, onClickListener).show();


To answer the second part of your question, you need to do things like

LV_DISPINFO dispinfo;  
dispinfo.item.pszText = LPTSTR((LPCTSTR)string);

because MS's LVITEM struct has an LPTSTR, i.e. a mutable T-string pointer, not an LPCTSTR. What you are doing is

1) convert string (a CString at a guess) into an LPCTSTR (which in practise means getting the address of its character buffer as a read-only pointer)

2) convert that read-only pointer into a writeable pointer by casting away its const-ness.

It depends what dispinfo is used for whether or not there is a chance that your ListView call will end up trying to write through that pszText. If it does, this is a potentially very bad thing: after all you were given a read-only pointer and then decided to treat it as writeable: maybe there is a reason it was read-only!

If it is a CString you are working with you have the option to use string.GetBuffer() -- that deliberately gives you a writeable LPTSTR. You then have to remember to call ReleaseBuffer() if the string does get changed. Or you can allocate a local temporary buffer and copy the string into there.

99% of the time this will be unnecessary and treating the LPCTSTR as an LPTSTR will work... but one day, when you least expect it...

Converting a generic list to a CSV string

As the code in the link given by @Frank Create a CSV File from a .NET Generic List there was a little issue of ending every line with a , I modified the code to get rid of it.Hope it helps someone.

/// <summary>
/// Creates the CSV from a generic list.
/// </summary>;
/// <typeparam name="T"></typeparam>;
/// <param name="list">The list.</param>;
/// <param name="csvNameWithExt">Name of CSV (w/ path) w/ file ext.</param>;
public static void CreateCSVFromGenericList<T>(List<T> list, string csvCompletePath)
    if (list == null || list.Count == 0) return;

    //get type from 0th member
    Type t = list[0].GetType();
    string newLine = Environment.NewLine;

    if (!Directory.Exists(Path.GetDirectoryName(csvCompletePath))) Directory.CreateDirectory(Path.GetDirectoryName(csvCompletePath));

    if (!File.Exists(csvCompletePath)) File.Create(csvCompletePath);

    using (var sw = new StreamWriter(csvCompletePath))
        //make a new instance of the class name we figured out to get its props
        object o = Activator.CreateInstance(t);
        //gets all properties
        PropertyInfo[] props = o.GetType().GetProperties();

        //foreach of the properties in class above, write out properties
        //this is the header row
        sw.Write(string.Join(",", props.Select(d => d.Name).ToArray()) + newLine);

        //this acts as datarow
        foreach (T item in list)
            //this acts as datacolumn
            var row = string.Join(",", props.Select(d => item.GetType()
                                                            .GetValue(item, null)
            sw.Write(row + newLine);


How to view Plugin Manager in Notepad++

A direct process to install / configure Plugin Manager :

  1. Download the latest version of NotepadPlus Plugin Manager from the official Github handle.
  2. Extract the zip file.
  3. Copy the pluginmanager.dll file and paste in C:\Program Files\Notepad++\Plugins\PluginManager directory.
  4. Restart the Notepad++

Note: Create the PluginManager directory if it is not present.

Preventing scroll bars from being hidden for MacOS trackpad users in WebKit/Blink

Here is a shorter bit of code that reenables scroll bars across your entire website. I'm not sure if it's much different than the current most popular answer but here it is:

::-webkit-scrollbar {
    -webkit-appearance: none;
    width: 7px;
::-webkit-scrollbar-thumb {
    border-radius: 4px;
    background-color: rgba(0,0,0,.5);
    box-shadow: 0 0 1px rgba(255,255,255,.5);

Found at this link:

Syntax for a single-line Bash infinite while loop

You can also make use of until command:

until ((0)); do foo; sleep 2; done

Note that in contrast to while, until would execute the commands inside the loop as long as the test condition has an exit status which is not zero.

Using a while loop:

while read i; do foo; sleep 2; done < /dev/urandom

Using a for loop:

for ((;;)); do foo; sleep 2; done

Another way using until:

until [ ]; do foo; sleep 2; done

Remove the last character from a string

You can use

substr(string $string, int $start, int[optional] $length=null);

See substr in the PHP documentation. It returns part of a string.

Inserting a Python datetime.datetime object into MySQL

For a time field, use:

import time    
time.strftime('%Y-%m-%d %H:%M:%S')

I think strftime also applies to datetime.

How do you make an array of structs in C?


struct body bodies[n];

to after

struct body
    double p[3];//position
    double v[3];//velocity
    double a[3];//acceleration
    double radius;
    double mass;

Rest all looks fine.

Javascript callback when IFRAME is finished loading?

I have had to do this in cases where documents such as word docs and pdfs were being streamed to the iframe and found a solution that works pretty well. The key is handling the onreadystatechanged event on the iframe.

Lets say the name of your frame is "myIframe". First somewhere in your code startup (I do it inline any where after the iframe) add something like this to register the event handler:

document.getElementById('myIframe').onreadystatechange = MyIframeReadyStateChanged;

I was not able to use an onreadystatechage attribute on the iframe, I can't remember why, but the app had to work in IE 7 and Safari 3, so that may of been a factor.

Here is an example of a how to get the complete state:

function MyIframeReadyStateChanged()
    if(document.getElementById('myIframe').readyState == 'complete')
        // Do your complete stuff here.

How can getContentResolver() be called in Android?

Access contentResolver in Kotlin , inside activities, Object classes &... :


How I can filter a Datatable?

use it:



string _sqlWhere = "Nachname = 'test'";
string _sqlOrder = "Nachname DESC";

DataTable _newDataTable = yurDateTable.Select(_sqlWhere, _sqlOrder).CopyToDataTable();

Create array of regex matches

(4castle's answer is better than the below if you can assume Java >= 9)

You need to create a matcher and use that to iteratively find matches.

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


 List<String> allMatches = new ArrayList<String>();
 Matcher m = Pattern.compile("your regular expression here")
 while (m.find()) {

After this, allMatches contains the matches, and you can use allMatches.toArray(new String[0]) to get an array if you really need one.

You can also use MatchResult to write helper functions to loop over matches since Matcher.toMatchResult() returns a snapshot of the current group state.

For example you can write a lazy iterator to let you do

for (MatchResult match : allMatches(pattern, input)) {
  // Use match, and maybe break without doing the work to find all possible matches.

by doing something like this:

public static Iterable<MatchResult> allMatches(
      final Pattern p, final CharSequence input) {
  return new Iterable<MatchResult>() {
    public Iterator<MatchResult> iterator() {
      return new Iterator<MatchResult>() {
        // Use a matcher internally.
        final Matcher matcher = p.matcher(input);
        // Keep a match around that supports any interleaving of hasNext/next calls.
        MatchResult pending;

        public boolean hasNext() {
          // Lazily fill pending, and avoid calling find() multiple times if the
          // clients call hasNext() repeatedly before sampling via next().
          if (pending == null && matcher.find()) {
            pending = matcher.toMatchResult();
          return pending != null;

        public MatchResult next() {
          // Fill pending if necessary (as when clients call next() without
          // checking hasNext()), throw if not possible.
          if (!hasNext()) { throw new NoSuchElementException(); }
          // Consume pending so next call to hasNext() does a find().
          MatchResult next = pending;
          pending = null;
          return next;

        /** Required to satisfy the interface, but unsupported. */
        public void remove() { throw new UnsupportedOperationException(); }

With this,

for (MatchResult match : allMatches(Pattern.compile("[abc]"), "abracadabra")) {
  System.out.println( + " at " + match.start());


a at 0
b at 1
a at 3
c at 4
a at 5
a at 7
b at 8
a at 10

How to get pixel data from a UIImage (Cocoa Touch) or CGImage (Core Graphics)?

NSString * path = [[NSBundle mainBundle] pathForResource:@"filename" ofType:@"jpg"];
UIImage * img = [[UIImage alloc]initWithContentsOfFile:path];
CGImageRef image = [img CGImage];
CFDataRef data = CGDataProviderCopyData(CGImageGetDataProvider(image));
const unsigned char * buffer =  CFDataGetBytePtr(data);

JavaScript, get date of the next day

You can use:

var tomorrow = new Date();
tomorrow.setDate(new Date().getDate()+1);

For example, since there are 30 days in April, the following code will output May 1:

var day = new Date('Apr 30, 2000');
console.log(day); // Apr 30 2000

var nextDay = new Date(day);
nextDay.setDate(day.getDate() + 1);
console.log(nextDay); // May 01 2000    

See fiddle.


i got similar issue once, what i observed was, package name in my Androidmanifest.xml was started with one empty space character. like " com.example.test" instead of "com.example.test"

I removed all such invalid spaces from my manifest file, it solved my problem

Edit 1: '-' in package name also cause same issue on some android versions

Checking the equality of two slices

And for now, here is which

is intended to be a more powerful and safer alternative to reflect.DeepEqual for comparing whether two values are semantically equal.

package main

import (


func main() {
    a := []byte{1, 2, 3}
    b := []byte{1, 2, 3}

    fmt.Println(cmp.Equal(a, b)) // true

How can I set the color of a selected row in DataGrid

The above solution left blue border around each cell in my case.

This is the solution that worked for me. It is very simple, just add this to your DataGrid. You can change it from a SolidColorBrush to any other brush such as linear gradient.

  <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" 

What is the difference between the HashMap and Map objects in Java?

You create the same maps.

But you can fill the difference when you will use it. With first case you'll be able to use special HashMap methods (but I don't remember anyone realy useful), and you'll be able to pass it as a HashMap parameter:

public void foo (HashMap<String, Object) { ... }


HashMap<String, Object> m1 = ...;
Map<String, Object> m2 = ...;

foo (m1);
foo ((HashMap<String, Object>)m2); 

Case-insensitive search in Rails model

You can also use scopes like this below and put them in a concern and include in models you may need them:

scope :ci_find, lambda { |column, value| where("lower(#{column}) = ?", value.downcase).first }

Then use like this: Model.ci_find('column', 'value')

SQLAlchemy equivalent to SQL "LIKE" statement

try this code

output = dbsession.query(<model_class>).filter(<model_calss>.email.ilike('%' + < email > + '%'))

Python check if website exists

def isok(mypath):
        thepage = urllib.request.urlopen(mypath)
    except HTTPError as e:
        return 0
    except URLError as e:
        return 0
        return 1

How can I jump to class/method definition in Atom text editor?

Here are the shortcuts for both mac and windows:

For Mac: command + G

For Windows: CTRL+ALT+G

Synchronous Requests in Node.js

You can do something exactly similar with the request library, but this is sync using const https = require('https'); or const http = require('http');, which should come with node.

Here is an example,

const https = require('https');

const http_get1 = {
    host : '',
    port : '443',
    path : '/youtube/v3/search?arg=1',
    method : 'GET',
    headers : {
        'Content-Type' : 'application/json'

const http_get2 = {
host : '',
    port : '443',
    path : '/youtube/v3/search?arg=2',
    method : 'GET',
    headers : {
        'Content-Type' : 'application/json'

let data1 = '';
let data2 = '';

function master() {





const req1 = https.request(http_get1, (res) => {

    res.on('data', (chunk) => {
        data1 += chunk;

    res.on('end', () => {

const req2 = https.request(http_get2, (res) => {

    res.on('data', (chunk) => {
        data2 += chunk;

    res.on('end', () => {


What does "javax.naming.NoInitialContextException" mean?

In extremely non-technical terms, it may mean that you forgot to put "ejb:" or "jdbc:" or something at the very beginning of the URI you are trying to connect.

Xcode 6 iPhone Simulator Application Support location

The simulator puts the file in ~/Library/Developer/CoreSimulator/Devices/... but the path after /Devices is different for everyone.

Use this handy method. It returns the path of the temporary directory for the current user and takes no argument.

NSString * NSTemporaryDirectory ( void );

So in my ViewController class I usually put this line in my viewDidLoad just for a reference when I need to grab my CoreData stored file. Hope this helps.

  NSLog(@"FILE PATH :%@", NSTemporaryDirectory());

(Note: to go to the path, from the finder menu click on Go and type ~/Library to open hidden directory then in the Finder Window you can click on the path shown on your console.)

Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema

Webpack's configuration file has changed over the years (likely with each major release). The answer to the question:

Why do I get this error

Invalid configuration object. Webpack has been initialised using a 
configuration object that does not match the API schema

is because the configuration file doesn't match the version of webpack being used.

The accepted answer doesn't state this and other answers allude to this but don't state it clearly npm install [email protected], Just change from "loaders" to "rules" in "webpack.config.js", and this. So I decide to provide my answer to this question.

Uninstalling and re-installing webpack, or using the global version of webpack will not fix this problem. Using the correct version of webpack for the configuration file being used is what is important.

If this problem was fixed when using a global version it likely means that your global version was "old" and the webpack.config.js file format your using is "old" so they match and viola things now work. I'm all for things working, but want readers to know why they worked.

Whenever you get a webpack configuration that you hope is going to solve your problem ... ask yourself what version of webpack the configuration is for.

There are a lot of good resources for learning webpack. Some are:

There are a lot more good resources for learning webpack4 by example, please add comments if you know of others. Hopefully, future webpack articles will state the versions being used/explained.

Remove last character of a StringBuilder?

As of Java 8, the String class has a static method join. The first argument is a string that you want between each pair of strings, and the second is an Iterable<CharSequence> (which are both interfaces, so something like List<String> works. So you can just do this:

String.join(",", serverIds);

Also in Java 8, you could use the new StringJoiner class, for scenarios where you want to start constructing the string before you have the full list of elements to put in it.

xls to csv converter

@andi I tested your code, it works great, BUT

In my sheets there's a column like this


date and time in the same cell

It gets garbled during exportation, it's like this in the exported file


other columns are ok.

csvkit, on the other side, does ok with that column but only exports ONE sheet, and my files have many.

How to remove a virtualenv created by "pipenv run"

I know that question is a bit old but

In root of project where Pipfile is located you could run

pipenv --venv

which returns


and then remove this env by typing

rm -rf /Users/your_user_name/.local/share/virtualenvs/model-N-S4uBGU

In PANDAS, how to get the index of a known value?

To get the index by value, simply add .index[0] to the end of a query. This will return the index of the first row of the result...

So, applied to your dataframe:

In [1]: a[a['c2'] == 1].index[0]     In [2]: a[a['c1'] > 7].index[0]   
Out[1]: 0                            Out[2]: 4                         

Where the query returns more than one row, the additional index results can be accessed by specifying the desired index, e.g. .index[n]

In [3]: a[a['c2'] >= 7].index[1]     In [4]: a[(a['c2'] > 1) & (a['c1'] < 8)].index[2]  
Out[3]: 4                            Out[4]: 3 

jQuery ajax success callback function definition

I do not know why you are defining the parameter outside the script. That is unnecessary. Your callback function will be called with the return data as a parameter automatically. It is very possible to define your callback outside the sucess: i.e.

function getData() {
        url : '',
        type: 'GET',
        success : handleData

function handleData(data) {
    //do some stuff

the handleData function will be called and the parameter passed to it by the ajax function.

C# how to convert File.ReadLines into string array?

File.ReadLines() returns an object of type System.Collections.Generic.IEnumerable<String>
File.ReadAllLines() returns an array of strings.

If you want to use an array of strings you need to call the correct function.

You could use Jim solution, just use ReadAllLines() or you could change your return type.

This would also work:

System.Collections.Generic.IEnumerable<String> lines = File.ReadLines("c:\\file.txt");

You can use any generic collection which implements IEnumerable. IList for an example.

How to save MySQL query output to excel or .txt file?

From Save MySQL query results into a text or CSV file:

MySQL provides an easy mechanism for writing the results of a select statement into a text file on the server. Using extended options of the INTO OUTFILE nomenclature, it is possible to create a comma separated value (CSV) which can be imported into a spreadsheet application such as OpenOffice or Excel or any other application which accepts data in CSV format.

Given a query such as

SELECT order_id,product_name,qty FROM orders

which returns three columns of data, the results can be placed into the file /tmp/orders.txt using the query:

SELECT order_id,product_name,qty FROM orders
INTO OUTFILE '/tmp/orders.txt'

This will create a tab-separated file, each row on its own line. To alter this behavior, it is possible to add modifiers to the query:

SELECT order_id,product_name,qty FROM orders
INTO OUTFILE '/tmp/orders.csv'

In this example, each field will be enclosed in double quotes, the fields will be separated by commas, and each row will be output on a new line separated by a newline (\n). Sample output of this command would look like:

"1","Tech-Recipes sock puppet","14.95" "2","Tech-Recipes chef's hat","18.95"

Keep in mind that the output file must not already exist and that the user MySQL is running as has write permissions to the directory MySQL is attempting to write the file to.


   SELECT Your_Column_Name
    FROM Your_Table_Name
    INTO OUTFILE 'Filename.csv'

Or you could try to grab the output via the client:

You could try executing the query from the your local client and redirect the output to a local file destination:

mysql -user -pass -e "select cols from table where cols not null" > /tmp/output

Hint: If you don't specify an absoulte path but use something like INTO OUTFILE 'output.csv' or INTO OUTFILE './output.csv', it will store the output file to the directory specified by show variables like 'datadir';.

How does DateTime.Now.Ticks exactly work?

The resolution of DateTime.Now depends on your system timer (~10ms on a current Windows OS) it's giving the same ending value there (it doesn't count any more finite than that).

No 'Access-Control-Allow-Origin' - Node / Apache Port Issue

Another way, is simply add the headers to your route:

router.get('/', function(req, res) {
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE'); // If needed
    res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type'); // If needed
    res.setHeader('Access-Control-Allow-Credentials', true); // If needed

    res.send('cors problem fixed:)');

How to create a pivot query in sql server without aggregate function

Check this out as well: using xml path and pivot


| ACCOUNT | 2000 | 2001 | 2002 |
|   Asset |  205 |  142 |  421 |
|  Equity |  365 |  214 |  163 |
|  Profit |  524 |  421 |  325 |

    @query  AS NVARCHAR(MAX)

SET @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.period) 
            FROM demo c
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 

set @query = 'SELECT account, ' + @cols + ' from 
                select account
                    , value
                    , period
                from demo
           ) x
                for period in (' + @cols + ')
            ) p '


Switch php versions on commandline ubuntu 16.04

type this in your command line, should work for all ubuntu between 16.04, 18.04 and 20.04.

$ sudo update-alternatives --config php

and this is what you will get

There are 4 choices for the alternative php (providing /usr/bin/php).

  Selection    Path             Priority   Status
* 0            /usr/bin/php7.2   72        auto mode
  1            /usr/bin/php5.6   56        manual mode
  2            /usr/bin/php7.0   70        manual mode
  3            /usr/bin/php7.1   71        manual mode
  4            /usr/bin/php7.2   72        manual mode
Press <enter> to keep the current choice[*], or type selection number:

Choose the appropriate version

How to find a number in a string using JavaScript?

var regex = /\d+/g;_x000D_
var string = "you can enter 30%-20% maximum 500 choices";_x000D_
var matches = string.match(regex);  // creates array from matches_x000D_

Lua String replace


name = "^aH^ai"
name = name:gsub("%^a", "")

See also:

Usage of __slots__?

Quoting Jacob Hallen:

The proper use of __slots__ is to save space in objects. Instead of having a dynamic dict that allows adding attributes to objects at anytime, there is a static structure which does not allow additions after creation. [This use of __slots__ eliminates the overhead of one dict for every object.] While this is sometimes a useful optimization, it would be completely unnecessary if the Python interpreter was dynamic enough so that it would only require the dict when there actually were additions to the object.

Unfortunately there is a side effect to slots. They change the behavior of the objects that have slots in a way that can be abused by control freaks and static typing weenies. This is bad, because the control freaks should be abusing the metaclasses and the static typing weenies should be abusing decorators, since in Python, there should be only one obvious way of doing something.

Making CPython smart enough to handle saving space without __slots__ is a major undertaking, which is probably why it is not on the list of changes for P3k (yet).

html vertical align the text inside input type button

Use the <button> tag instead. <button> labels are vertically centered by default.

How to receive POST data in django

res = request.GET['paymentid'] will raise a KeyError if paymentid is not in the GET data.

Your sample php code checks to see if paymentid is in the POST data, and sets $payID to '' otherwise:

$payID = isset($_POST['paymentid']) ? $_POST['paymentid'] : ''

The equivalent in python is to use the get() method with a default argument:

payment_id = request.POST.get('payment_id', '')

while debugging, this is what I see in the response.GET: <QueryDict: {}>, request.POST: <QueryDict: {}>

It looks as if the problem is not accessing the POST data, but that there is no POST data. How are you are debugging? Are you using your browser, or is it the payment gateway accessing your page? It would be helpful if you shared your view.

Once you are managing to submit some post data to your page, it shouldn't be too tricky to convert the sample php to python.

How to select rows with no matching entry in another table?

I Dont Knew Which one Is Optimized (compared to @AdaTheDev ) but This one seems to be quicker when I use (atleast for me)

SELECT id  FROM  table_1 EXCEPT SELECT DISTINCT (table1_id) table1_id FROM table_2

If You want to get any other specific attribute you can use:

SELECT COUNT(*) FROM table_1 where id in (SELECT id  FROM  table_1 EXCEPT SELECT DISTINCT (table1_id) table1_id FROM table_2);

Angular JS: Full example of GET/POST/DELETE/PUT client for a REST/CRUD backend?

I'm the creator of Restangular.

You can take a look at this CRUD example to see how you can PUT/POST/GET elements without all that URL configuration and $resource configuration that you need to do. Besides it, you can then use nested resources without any configuration :).

Check out this plunkr example:

You could also see the README and check the documentation here

If you need some feature that's not there, just create an issue. I usually add features asked within a week, as I also use this library for all my AngularJS projects :)

Hope it helps!

Provisioning Profiles menu item missing from Xcode 5

For me, the refresh in xcode 5 prefs->accounts was doing nothing. At one point it showed me three profiles so I thought I was one refresh away, but after the next refresh it went back to just one profile, so I abandoned this method.

If anyone gets this far and is still struggling, here's what I did:

  1. Close xcode 5
  2. Open xcode 4.6.2
  3. Go to Window->Organizer->Provisioning Profiles
  4. Press Refresh arrow on bottom right

When I did this, everything synced up perfectly. It even told me what it was downloading each step of the way like good software does. After the sync completed, I closed xcode 4.6.2, re-opened xcode 5 and went to preferences->accounts and voila, all of my profiles are now available in xocde 5.

changing kafka retention period during runtime

log.retention.hours is a property of a broker which is used as a default value when a topic is created. When you change configurations of currently running topic using, you should specify a topic-level property.

A topic-level property for log retention time is

From Topic-level configuration in Kafka 0.8.1 documentation:

  • Property:
  • Default: 7 days
  • Server Default Property: log.retention.minutes
  • Description: This configuration controls the maximum time we will retain a log before we will discard old log segments to free up space if we are using the "delete" retention policy. This represents an SLA on how soon consumers must read their data.

So the correct command depends on the version. Up to 0.8.2 (although docs still show its use up to 0.10.1) use --alter and after 0.10.2 (or perhaps from 0.9.0 going forward) use --alter

$ bin/ --zookeeper --alter --topic as-access --config

You can check whether the configuration is properly applied with the following command.

$ bin/ --describe --zookeeper --topic as-access

Then you will see something like below.

Topic:as-access  PartitionCount:3  ReplicationFactor:3

Convert MFC CString to integer

Define in msdn:

int atoi(
   const char *str 
int _wtoi(
   const wchar_t *str 
int _atoi_l(
   const char *str,
   _locale_t locale
int _wtoi_l(
   const wchar_t *str,
   _locale_t locale

CString is wchar_t string. So, if you want convert Cstring to int, you can use:

 CString s;  
int test = _wtoi(s)

Is it possible to view RabbitMQ message contents directly from the command line?

you can use RabbitMQ API to get count or messages :


Get messages from a queue. (This is not an HTTP GET as it will alter the state of the queue.) You should post a body looking like:


count controls the maximum number of messages to get. You may get fewer messages than this if the queue cannot immediately provide them.

requeue determines whether the messages will be removed from the queue. If requeue is true they will be requeued - but their redelivered flag will be set. encoding must be either "auto" (in which case the payload will be returned as a string if it is valid UTF-8, and base64 encoded otherwise), or "base64" (in which case the payload will always be base64 encoded). If truncate is present it will truncate the message payload if it is larger than the size given (in bytes). truncate is optional; all other keys are mandatory.

Please note that the publish / get paths in the HTTP API are intended for injecting test messages, diagnostics etc - they do not implement reliable delivery and so should be treated as a sysadmin's tool rather than a general API for messaging.

How to pass multiple parameters to a get method in ASP.NET Core

I think the easiest way is to simply use AttributeRouting.

    public string Get(int paramOne, int paramTwo)
        return "The [Route] with multiple params worked";

How do I format a string using a dictionary in python-3.x?

As Python 3.0 and 3.1 are EOL'ed and no one uses them, you can and should use str.format_map(mapping) (Python 3.2+):

Similar to str.format(**mapping), except that mapping is used directly and not copied to a dict. This is useful if for example mapping is a dict subclass.

What this means is that you can use for example a defaultdict that would set (and return) a default value for keys that are missing:

>>> from collections import defaultdict
>>> vals = defaultdict(lambda: '<unset>', {'bar': 'baz'})
>>> 'foo is {foo} and bar is {bar}'.format_map(vals)
'foo is <unset> and bar is baz'

Even if the mapping provided is a dict, not a subclass, this would probably still be slightly faster.

The difference is not big though, given

>>> d = dict(foo='x', bar='y', baz='z')


>>> 'foo is {foo}, bar is {bar} and baz is {baz}'.format_map(d)

is about 10 ns (2 %) faster than

>>> 'foo is {foo}, bar is {bar} and baz is {baz}'.format(**d)

on my Python 3.4.3. The difference would probably be larger as more keys are in the dictionary, and

Note that the format language is much more flexible than that though; they can contain indexed expressions, attribute accesses and so on, so you can format a whole object, or 2 of them:

>>> p1 = {'latitude':41.123,'longitude':71.091}
>>> p2 = {'latitude':56.456,'longitude':23.456}
>>> '{0[latitude]} {0[longitude]} - {1[latitude]} {1[longitude]}'.format(p1, p2)
'41.123 71.091 - 56.456 23.456'

Starting from 3.6 you can use the interpolated strings too:

>>> f'lat:{p1["latitude"]} lng:{p1["longitude"]}'
'lat:41.123 lng:71.091'

You just need to remember to use the other quote characters within the nested quotes. Another upside of this approach is that it is much faster than calling a formatting method.

How can I generate a self-signed certificate with SubjectAltName using OpenSSL?

Can someone help me with the exact syntax?

It's a three-step process, and it involves modifying the openssl.cnf file. You might be able to do it with only command line options, but I don't do it that way.

Find your openssl.cnf file. It is likely located in /usr/lib/ssl/openssl.cnf:

$ find /usr/lib -name openssl.cnf

On my Debian system, /usr/lib/ssl/openssl.cnf is used by the built-in openssl program. On recent Debian systems it is located at /etc/ssl/openssl.cnf

You can determine which openssl.cnf is being used by adding a spurious XXX to the file and see if openssl chokes.

First, modify the req parameters. Add an alternate_names section to openssl.cnf with the names you want to use. There are no existing alternate_names sections, so it does not matter where you add it.

[ alternate_names ]

DNS.1        =
DNS.2        =
DNS.3        =
DNS.4        =

Next, add the following to the existing [ v3_ca ] section. Search for the exact string [ v3_ca ]:

subjectAltName      = @alternate_names

You might change keyUsage to the following under [ v3_ca ]:

keyUsage = digitalSignature, keyEncipherment

digitalSignature and keyEncipherment are standard fare for a server certificate. Don't worry about nonRepudiation. It's a useless bit thought up by computer science guys/gals who wanted to be lawyers. It means nothing in the legal world.

In the end, the IETF (RFC 5280), browsers and CAs run fast and loose, so it probably does not matter what key usage you provide.

Second, modify the signing parameters. Find this line under the CA_default section:

# Extension copying option: use with caution.
# copy_extensions = copy

And change it to:

# Extension copying option: use with caution.
copy_extensions = copy

This ensures the SANs are copied into the certificate. The other ways to copy the DNS names are broken.

Third, generate your self-signed certificate:

$ openssl genrsa -out private.key 3072
$ openssl req -new -x509 -key private.key -sha256 -out certificate.pem -days 730
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.

Finally, examine the certificate:

$ openssl x509 -in certificate.pem -text -noout
        Version: 3 (0x2)
        Serial Number: 9647297427330319047 (0x85e215e5869042c7)
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=US, ST=MD, L=Baltimore, O=Test CA, Limited, CN=Test CA/[email protected]
            Not Before: Feb  1 05:23:05 2014 GMT
            Not After : Feb  1 05:23:05 2016 GMT
        Subject: C=US, ST=MD, L=Baltimore, O=Test CA, Limited, CN=Test CA/[email protected]
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (3072 bit)
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Subject Key Identifier:
            X509v3 Authority Key Identifier:

            X509v3 Basic Constraints: critical
            X509v3 Key Usage:
                Digital Signature, Non Repudiation, Key Encipherment, Certificate Sign
            X509v3 Subject Alternative Name:
    Signature Algorithm: sha256WithRSAEncryption

Finding the type of an object in C++

dynamic_cast should do the trick

TYPE& dynamic_cast<TYPE&> (object);
TYPE* dynamic_cast<TYPE*> (object);

The dynamic_cast keyword casts a datum from one pointer or reference type to another, performing a runtime check to ensure the validity of the cast.

If you attempt to cast to pointer to a type that is not a type of actual object, the result of the cast will be NULL. If you attempt to cast to reference to a type that is not a type of actual object, the cast will throw a bad_cast exception.

Make sure there is at least one virtual function in Base class to make dynamic_cast work.

Wikipedia topic Run-time type information

RTTI is available only for classes that are polymorphic, which means they have at least one virtual method. In practice, this is not a limitation because base classes must have a virtual destructor to allow objects of derived classes to perform proper cleanup if they are deleted from a base pointer.

How would I create a UIAlertView in Swift?

Show UIAlertView in swift language :-

Protocol UIAlertViewDelegate

let alert = UIAlertView(title: "alertView", message: "This is alertView", delegate:self, cancelButtonTitle:"Cancel", otherButtonTitles: "Done", "Delete")

Show UIAlertViewController in swift language :-

let alert = UIAlertController(title: "Error", message: "Enter data in Text fields", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)

How to access the contents of a vector from a pointer to the vector in C++?

The easiest way use it as array is use vector::data() member.

PHP Warning: Module already loaded in Unknown on line 0

You should have a /etc/php2/conf.d directory (At least on Ubuntu I do) containing a bunch of .ini files which all get loaded when php runs. These files can contain duplicate settings that conflict with settings in php.ini. In my PHP installation I notice a file conf.d/20-intl.ini with an setting. I bet that's your conflict.

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

Did you check this line works perfectly & your string have value in it ?

string jsonString = sr.ReadToEnd();

if yes, try this code for last line:

ValueSet items = JsonConvert.DeserializeObject<ValueSet>(jsonString);

or if you have an array of json you can use list like this :

List<ValueSet> items = JsonConvert.DeserializeObject<List<ValueSet>>(jsonString);

good luck

Mockito verify order / sequence of method calls

Yes, this is described in the documentation. You have to use the InOrder class.

Example (assuming two mocks already created):

InOrder inOrder = inOrder(serviceAMock, serviceBMock);


multiprocessing: How do I share a dict among multiple processes?

multiprocessing is not like threading. Each child process will get a copy of the main process's memory. Generally state is shared via communication (pipes/sockets), signals, or shared memory.

Multiprocessing makes some abstractions available for your use case - shared state that's treated as local by use of proxies or shared memory:

Relevant sections:

How to set the part of the text view is clickable

I would suggest a different approach that I think requires less code and is more "localization-friendly".

Supposing that your destination activity is called "ActivityStack", define in the manifest an intent filter for it with a custom scheme (e.g. "myappscheme") in AndroidManifest.xml:

        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <data android:host="stack"/>
        <data android:scheme="myappscheme" />

Define the TextView without any special tag (it is important to NOT use the "android:autoLink" tag, see:

    android:text="@string/stack_string" />

then use a link with custom scheme and host in the text of the TextView as (in String.xml):

<string name="stack_string">Android is a Software <a href="myappscheme://stack">stack</a></string>

and "activate" the link with setMovementMethod() (in onCreate() for activities or onCreateView() for fragments):

TextView stack = findViewById(;

This will open the stack activity with a tap on the "stack" word.

When to use React setState callback

},() => {

How to set session variable in jquery?

You could try using HTML5s sessionStorage it lasts for the duration on the page session. A page session lasts for as long as the browser is open and survives over page reloads and restores. Opening a page in a new tab or window will cause a new session to be initiated.

sessionStorage.setItem("username", "John");

Browser Compatibility compatible with every A-grade browser, included iPhone or Android.

Ignore fields from Java object dynamically while sending as JSON from Spring MVC

I know I'm a bit late to the party, but I actually ran into this as well a few months back. All of the available solutions weren't very appealing to me (mixins? ugh!), so I ended up creating a new library to make this process cleaner. It's available here if anyone would like to try it out:

The basic usage is pretty simple, you use the JsonView object in your controller methods like so:

import com.monitorjbl.json.JsonView;
import static com.monitorjbl.json.Match.match;

@RequestMapping(method = RequestMethod.GET, value = "/myObject")
public void getMyObjects() {
    //get a list of the objects
    List<MyObject> list = myObjectService.list();

    //exclude expensive field
    JsonView.with(list).onClass(MyObject.class, match().exclude("contains"));

You can also use it outside of Spring:

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import static com.monitorjbl.json.Match.match;

ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addSerializer(JsonView.class, new JsonViewSerializer());

      .onClass(MyObject.class, match()
      .onClass(MySmallObject.class, match()

ubuntu "No space left on device" but there is tons of space

It's possible that you've run out of memory or some space elsewhere and it prompted the system to mount an overflow filesystem, and for whatever reason, it's not going away.

Try unmounting the overflow partition:

umount /tmp


umount overflow

JavaScript global event mechanism

It seems that window.onerror doesn't provide access to all possible errors. Specifically it ignores:

  1. <img> loading errors (response >= 400).
  2. <script> loading errors (response >= 400).
  3. global errors if you have many other libraries in your app also manipulating window.onerror in an unknown way (jquery, angular, etc.).
  4. probably many cases I haven't run into after exploring this now (iframes, stack overflow, etc.).

Here is the start of a script that catches many of these errors, so that you may add more robust debugging to your app during development.


 * Capture error data for debugging in web console.

var captures = [];

 * Wait until `window.onload`, so any external scripts
 * you might load have a chance to set their own error handlers,
 * which we don't want to override.

window.addEventListener('load', onload);

 * Custom global function to standardize 
 * window.onerror so it works like you'd think.
 * @see

window.onanyerror = window.onanyerror || onanyerrorx;

 * Hook up all error handlers after window loads.

function onload() {

 * Handle global window events.

function handleGlobal() {
  var onerrorx = window.onerror;
  window.addEventListener('error', onerror);

  function onerror(msg, url, line, col, error) {
    window.onanyerror.apply(this, arguments);
    if (onerrorx) return onerrorx.apply(null, arguments);

 * Handle ajax request errors.

function handleXMLHttp() {
  var sendx = XMLHttpRequest.prototype.send;
  window.XMLHttpRequest.prototype.send = function(){
    return sendx.apply(this, arguments);

 * Handle image errors.

function handleImage() {
  var ImageOriginal = window.Image;
  window.Image = ImageOverride;

   * New `Image` constructor. Might cause some problems,
   * but not sure yet. This is at least a start, and works on chrome.

  function ImageOverride() {
    var img = new ImageOriginal;
    onnext(function(){ handleAsync(img); });
    return img;

 * Handle script errors.

function handleScript() {
  var HTMLScriptElementOriginal = window.HTMLScriptElement;
  window.HTMLScriptElement = HTMLScriptElementOverride;

   * New `HTMLScriptElement` constructor.
   * Allows us to globally override onload.
   * Not ideal to override stuff, but it helps with debugging.

  function HTMLScriptElementOverride() {
    var script = new HTMLScriptElement;
    onnext(function(){ handleAsync(script); });
    return script;

 * Handle errors in events.
 * @see

function handleEvents() {
  var addEventListenerx = window.EventTarget.prototype.addEventListener;
  window.EventTarget.prototype.addEventListener = addEventListener;
  var removeEventListenerx = window.EventTarget.prototype.removeEventListener;
  window.EventTarget.prototype.removeEventListener = removeEventListener;

  function addEventListener(event, handler, bubble) {
    var handlerx = wrap(handler);
    return, event, handlerx, bubble);

  function removeEventListener(event, handler, bubble) {
    handler = handler._witherror || handler;, event, handler, bubble);

  function wrap(fn) {
    fn._witherror = witherror;

    function witherror() {
      try {
        fn.apply(this, arguments);
      } catch(e) {
        window.onanyerror.apply(this, e);
        throw e;
    return fn;

 * Handle image/ajax request errors generically.

function handleAsync(obj) {
  var onerrorx = obj.onerror;
  obj.onerror = onerror;
  var onabortx = obj.onabort;
  obj.onabort = onabort;
  var onloadx = obj.onload;
  obj.onload = onload;

   * Handle `onerror`.

  function onerror(error) {, error);
    if (onerrorx) return onerrorx.apply(this, arguments);

   * Handle `onabort`.

  function onabort(error) {, error);
    if (onabortx) return onabortx.apply(this, arguments);

   * Handle `onload`.
   * For images, you can get a 403 response error,
   * but this isn't triggered as a global on error.
   * This sort of standardizes it.
   * "there is no way to get the HTTP status from a 
   * request made by an img tag in JavaScript."
   * @see

  function onload(request) {
    if (request.status && request.status >= 400) {, request);
    if (onloadx) return onloadx.apply(this, arguments);

 * Generic error handler.
 * This shows the basic implementation, 
 * which you could override in your app.

function onanyerrorx(entity) {
  var display = entity;

  // ajax request
  if (entity instanceof XMLHttpRequest) {
    // 400:
    display = entity.status + ' ' + entity.responseURL;
  } else if (entity instanceof Event) {
    // global window events, or image events
    var target = entity.currentTarget;
    display = target;
  } else {
    // not sure if there are others

  console.log('[onanyerror]', display, entity);

 * Capture stuff for debugging purposes.
 * Keep them in memory so you can reference them
 * in the chrome debugger as `onanyerror0` up to `onanyerror99`.

function capture(entity) {
  if (captures.length > 100) captures.unshift();

  // keep the last ones around
  var i = captures.length;
  while (--i) {
    var x = captures[i];
    window['onanyerror' + i] = x;

 * Wait til next code execution cycle as fast as possible.

function onnext(fn) {
  setTimeout(fn, 0);


It could be used like this:

window.onanyerror = function(entity){
  console.log('some error', entity);

The full script has a default implementation that tries to print out a semi-readable "display" version of the entity/error that it receives. Can be used for inspiration for an app-specific error handler. The default implementation also keeps a reference to the last 100 error entities, so you can inspect them in the web console after they occur like:


Note: This works by overriding methods on several browser/native constructors. This can have unintended side-effects. However, it has been useful to use during development, to figure out where errors are occurring, to send logs to services like NewRelic or Sentry during development so we can measure errors during development, and on staging so we can debug what is going on at a deeper level. It can then be turned off in production.

Hope this helps.

Can you style html form buttons with css?

Yes you can target those specificaly using input[type=submit] e.g.

.myFormClass input[type=submit] {
  margin: 10px;
  color: white;
  background-color: blue;

How to regex in a MySQL query

In my case (Oracle), it's WHERE REGEXP_LIKE(column, 'regex.*'). See here:

SQL Function



This function searches a character column for a pattern. Use this function in the WHERE clause of a query to return rows matching the regular expression you specify.



This function searches for a pattern in a character column and replaces each occurrence of that pattern with the pattern you specify.



This function searches a string for a given occurrence of a regular expression pattern. You specify which occurrence you want to find and the start position to search from. This function returns an integer indicating the position in the string where the match is found.



This function returns the actual substring matching the regular expression pattern you specify.

(Of course, REGEXP_LIKE only matches queries containing the search string, so if you want a complete match, you'll have to use '^$' for a beginning (^) and end ($) match, e.g.: '^regex.*$'.)

Multidimensional Lists in C#

It's old but thought I'd add my two cents... Not sure if it will work but try using a KeyValuePair:

 List<KeyValuePair<?, ?>> LinkList = new List<KeyValuePair<?, ?>>();
 LinkList.Add(new KeyValuePair<?, ?>(Object, Object));

You'll end up with something like this:

 LinkList[0] = <Object, Object>
 LinkList[1] = <Object, Object>
 LinkList[2] = <Object, Object>

and so on...

Scroll to bottom of div with Vue.js

  1. Use ref attribute on DOM element for reference
<div class="content scrollable" ref="msgContainer">
    <!-- content -->
  1. You need to setup a WATCH
  data() {
    return {
      count: 5
  watch: {
    count: function() {
      this.$nextTick(function() {
        var container = this.$refs.msgContainer;
        container.scrollTop = container.scrollHeight + 120;
  1. Ensure you're using proper CSS
.scrollable {
  overflow: hidden;
  overflow-y: scroll;
  height: calc(100vh - 20px);

Angular ng-repeat add bootstrap row every 3 or 4 cols

Little bit modification in @alpar 's solution

<div data-ng-app="" data-ng-init="products=['A','B','C','D','E','F', 'G','H','I','J','K','L']" class="container">
    <div ng-repeat="product in products" ng-if="$index % 6 == 0" class="row">
        <div class="col-xs-2" ng-repeat="idx in [0,1,2,3,4,5]">
        {{products[idx+$parent.$index]}} <!-- When this HTML is Big it's useful approach -->


Best place to insert the Google Analytics code

Yes, it is recommended to put the GA code in the footer anyway, as the page shouldnt count as a page visit until its read all the markup.

Comparing two byte arrays in .NET

You can use Enumerable.SequenceEqual method.

using System;
using System.Linq;
var a1 = new int[] { 1, 2, 3};
var a2 = new int[] { 1, 2, 3};
var a3 = new int[] { 1, 2, 4};
var x = a1.SequenceEqual(a2); // true
var y = a1.SequenceEqual(a3); // false

If you can't use .NET 3.5 for some reason, your method is OK.
Compiler\run-time environment will optimize your loop so you don't need to worry about performance.

How to get the directory of the currently running file?

if you use this way :

dir, err := filepath.Abs(filepath.Dir(os.Args[0]))
if err != nil {

you will get the /tmp path when you are running program using some IDE like GoLang because the executable will save and run from /tmp

i think the best way for getting the currentWorking Directory or '.' is :


func main() {
  dir, err := os.Getwd()
    if err != nil {

the os.Getwd() function will return the current working directory. and its all without using of any external library :D

How to break out from a ruby block?

next and break seem to do the correct thing in this simplified example!

class Bar
  def self.do_things
      Foo.some_method(1..10) do |x|
            next if x == 2
            break if x == 9
            print "#{x} "

class Foo
    def self.some_method(targets, &block)
      targets.each do |target|
          r = yield(target)
        rescue  => x
          puts "rescue #{x}"


output: 1 3 4 5 6 7 8

#define macro for debug printing in C?

Here's the version I use:

#ifdef NDEBUG
#define Dprintf(FORMAT, ...) ((void)0)
#define Dputs(MSG) ((void)0)
#define Dprintf(FORMAT, ...) \
    fprintf(stderr, "%s() in %s, line %i: " FORMAT "\n", \
        __func__, __FILE__, __LINE__, __VA_ARGS__)
#define Dputs(MSG) Dprintf("%s", MSG)

Split an integer into digits to compute an ISBN checksum

Converting to str is definitely slower then dividing by 10.

map is sligthly slower than list comprehension:

convert to string with map 2.13599181175
convert to string with list comprehension 1.92812991142
modulo, division, recursive 0.948769807816
modulo, division 0.699964046478

These times were returned by the following code on my laptop:

foo = """\
def foo(limit):
    return sorted(set(map(sum, map(lambda x: map(int, list(str(x))), map(lambda x: x * 9, range(limit))))))


bar = """\
def bar(limit):
    return sorted(set([sum([int(i) for i in str(n)]) for n in [k *9 for k in range(limit)]]))


rac = """\
def digits(n):
    return [n] if n<10 else digits(n / 10)+[n %% 10]

def rabbit(limit):
    return sorted(set([sum(digits(n)) for n in [k *9 for k in range(limit)]]))


rab = """\
def sum_digits(number):
  result = 0
  while number:
    digit = number %% 10
    result += digit
    number /= 10
  return result

def rabbit(limit):
    return sorted(set([sum_digits(n) for n in [k *9 for k in range(limit)]]))


import timeit

print "convert to string with map", timeit.timeit(foo % 100, number=10000)
print "convert to string with list comprehension", timeit.timeit(bar % 100, number=10000)
print "modulo, division, recursive", timeit.timeit(rac % 100, number=10000)
print "modulo, division", timeit.timeit(rab % 100, number=10000)

When should I use Memcache instead of Memcached?

This is 2013. Forget about the 2009 comments. Likewise, if you are running serious traffic loads, do not even contemplate how to make-do with a windows based memcache. When dealing with a very large scale (500+ front end web servers) and 20+ back end database servers and replicants (mysql & mssql mix), a farm of memcached servers (12 servers in group) supports multiple high volume OLTP applications answering 25K ~ 40K mc->get calls per-second. These calls are those that do NOT have to reach a database.

IMHO, this use of memcached provided SERIOUS $$$,$$$savings on CAPEX for new DB servers & licences as well as on support contracts for large commercial designs.

React-Native: Module AppRegistry is not a registered callable module

I uninstalled it on Genymotion. Then run react-native run-android to build the app. And it worked. Do try this first before running sudo ./gradlew clean, it will save you a lot of time.

CSS: Control space between bullet and <li>

For list-style-type: inline:

It's almost the same like DSMann8's answer but less css code.

You just need to

    li:before {
        content: "";
        padding-left: 10px;

    <li>Some content</li>


Simplest way to wait some asynchronous tasks complete, in Javascript?

The way to do it is to pass the tasks a callback that updates a shared counter. When the shared counter reaches zero you know that all tasks have finished so you can continue with your normal flow.

var ntasks_left_to_go = 4;

var callback = function(){
    ntasks_left_to_go -= 1;
    if(ntasks_left_to_go <= 0){
         console.log('All tasks have completed. Do your stuff');


Of course, there are many ways to make this kind of code more generic or reusable and any of the many async programing libraries out there should have at least one function to do this kind of thing.

Find size of an array in Perl

To use the second way, add 1:

print $#arr + 1; # Second way to print array size

What is the best way to auto-generate INSERT statements for a SQL Server table?

I have also researched lot on this, but I could not get the concrete solution for this. Currently the approach I follow is copy the contents in excel from SQL Server Managment studio and then import the data into Oracle-TOAD and then generate the insert statements

Django optional url parameters

You can use nested routes

Django <1.8

urlpatterns = patterns(''
    url(r'^project_config/', include(patterns('',
        url(r'^$', ProjectConfigView.as_view(), name="project_config")
        url(r'^(?P<product>\w+)$', include(patterns('',
            url(r'^$', ProductView.as_view(), name="product"),
            url(r'^(?P<project_id>\w+)$', ProjectDetailView.as_view(), name="project_detail")

Django >=1.8

urlpatterns = [
    url(r'^project_config/', include([
        url(r'^$', ProjectConfigView.as_view(), name="project_config")
        url(r'^(?P<product>\w+)$', include([
            url(r'^$', ProductView.as_view(), name="product"),
            url(r'^(?P<project_id>\w+)$', ProjectDetailView.as_view(), name="project_detail")

This is a lot more DRY (Say you wanted to rename the product kwarg to product_id, you only have to change line 4, and it will affect the below URLs.

Edited for Django 1.8 and above

Error handling in getJSON calls

$.getJSON("example.json", function() {_x000D_
.success(function() { alert("second success"); })_x000D_
.error(function() { alert("error"); })

It is fixed in jQuery 2.x; In jQuery 1.x you will never get an error callback

Return index of greatest value in an array

Unless I'm mistaken, I'd say it's to write your own function.

function findIndexOfGreatest(array) {
  var greatest;
  var indexOfGreatest;
  for (var i = 0; i < array.length; i++) {
    if (!greatest || array[i] > greatest) {
      greatest = array[i];
      indexOfGreatest = i;
  return indexOfGreatest;

Copying one structure to another

Copying by plain assignment is best, since it's shorter, easier to read, and has a higher level of abstraction. Instead of saying (to the human reader of the code) "copy these bits from here to there", and requiring the reader to think about the size argument to the copy, you're just doing a plain assignment ("copy this value from here to here"). There can be no hesitation about whether or not the size is correct.

Also, if the structure is heavily padded, assignment might make the compiler emit something more efficient, since it doesn't have to copy the padding (and it knows where it is), but mempcy() doesn't so it will always copy the exact number of bytes you tell it to copy.

If your string is an actual array, i.e.:

struct {
  char string[32];
  size_t len;
} a, b;

strcpy(a.string, "hello");
a.len = strlen(a.string);

Then you can still use plain assignment:

b = a;

To get a complete copy. For variable-length data modelled like this though, this is not the most efficient way to do the copy since the entire array will always be copied.

Beware though, that copying structs that contain pointers to heap-allocated memory can be a bit dangerous, since by doing so you're aliasing the pointer, and typically making it ambiguous who owns the pointer after the copying operation.

For these situations a "deep copy" is really the only choice, and that needs to go in a function.

Compilation error - missing zlib.h

You are missing zlib.h header file, on Linux install it via:

sudo apt-get install libz-dev

As a matter of fact, the module presents as zlib1g-dev in the apt repo, so this is the up-to-date call (Feb 2019):

sudo apt install zlib1g-dev

On Fedora: sudo dnf install zlib-devel (in older versions: sudo dnf install libz-devel).

This will provide the development support files for a library implementing the deflate compression method found in gzip and PKZIP.

If you've already zlib library, make sure you're compiling your code sources with -lz. See: How to fix undefined references to inflate/deflate functions?.

What's the difference between JavaScript and Java?

Java and Javascript are similar like Car and Carpet are similar.

SQL Server : converting varchar to INT

You could try updating the table to get rid of these characters:

UPDATE dbo.[audit]
  SET UserID = REPLACE(UserID, CHAR(0), '')

But then you'll also need to fix whatever is putting this bad data into the table in the first place. In the meantime perhaps try:

  FROM dbo.[audit];

But that is not a long term solution. Fix the data (and the data type while you're at it). If you can't fix the data type immediately, then you can quickly find the culprit by adding a check constraint:

ALTER TABLE dbo.[audit]
  ADD CONSTRAINT do_not_allow_stupid_data


Ok, so that is definitely a 4-digit integer followed by six instances of CHAR(0). And the workaround I posted definitely works for me:

INSERT @foo SELECT 0x31353831000000000000;

-- this succeeds:

-- this fails:

Please confirm that this code on its own (well, the first SELECT, anyway) works for you. If it does then the error you are getting is from a different non-numeric character in a different row (and if it doesn't then perhaps you have a build where a particular bug hasn't been fixed). To try and narrow it down you can take random values from the following query and then loop through the characters:

  FROM dbo.[audit]
  WHERE UserID LIKE '%[^0-9]%';

So take a random row, and then paste the output into a query like this:

SET @x = CONVERT(VARCHAR(32), 0x...); -- paste the value here
SET @i = 1;
WHILE @i <= LEN(@x)
  PRINT RTRIM(@i) + ' = ' + RTRIM(ASCII(SUBSTRING(@x, @i, 1)))
  SET @i = @i + 1;

This may take some trial and error before you encounter a row that fails for some other reason than CHAR(0) - since you can't really filter out the rows that contain CHAR(0) because they could contain CHAR(0) and CHAR(something else). For all we know you have values in the table like:

SELECT '15' + CHAR(9) + '23' + CHAR(0);

...which also can't be converted to an integer, whether you've replaced CHAR(0) or not.

I know you don't want to hear it, but I am really glad this is painful for people, because now they have more war stories to push back when people make very poor decisions about data types.

SQL Group By with an Order By

In all versions of MySQL, simply alias the aggregate in the SELECT list, and order by the alias:

SELECT COUNT(id) AS theCount, `Tag` from `images-tags`

How to spawn a process and capture its STDOUT in .NET?

You need to call p.Start() to actually run the process after you set the StartInfo. As it is, your function is probably hanging on the WaitForExit() call because the process was never actually started.

When to use std::size_t?

size_t is the result type of the sizeof operator.

Use size_t for variables that model size or index in an array. size_t conveys semantics: you immediately know it represents a size in bytes or an index, rather than just another integer.

Also, using size_t to represent a size in bytes helps making the code portable.

How can I get the last day of the month in C#?

try this. It will solve your problem.

 var lastDayOfMonth = DateTime.DaysInMonth(int.Parse(ddlyear.SelectedValue), int.Parse(ddlmonth.SelectedValue));
DateTime tLastDayMonth = Convert.ToDateTime(lastDayOfMonth.ToString() + "/" + ddlmonth.SelectedValue + "/" + ddlyear.SelectedValue);

Hide Button After Click (With Existing Form on Page)

This is my solution. I Hide and then confirm check

onclick="return ConfirmSubmit(this);" />

function ConfirmSubmit(sender)
        sender.disabled = true;
        var displayValue = = 'none'

        if (confirm('Seguro que desea entregar los paquetes?')) {
            sender.disabled = false
            return true;

        sender.disabled = false; = displayValue;
        return false;

How can I make a multipart/form-data POST request using Java?

My code post multipartFile to server.

  public static HttpResponse doPost(
    String host,
    String path,
    String method,
    MultipartFile multipartFile
  ) throws IOException

    HttpClient httpClient = wrapClient(host);
    HttpPost httpPost = new HttpPost(buildUrl(host, path));

    if (multipartFile != null) {

      HttpEntity httpEntity;

      ContentBody contentBody;
      contentBody = new ByteArrayBody(multipartFile.getBytes(), multipartFile.getOriginalFilename());
      httpEntity = MultipartEntityBuilder.create()
                                         .addPart("nameOfMultipartFile", contentBody)


    return httpClient.execute(httpPost);

c++ Read from .csv file

That because your csv file is in invalid format, maybe the line break in your text file is not the \n or \r

and, using c/c++ to parse text is not a good idea. try awk:

 $awk -F"," '{print "ID="$1"\tName="$2"\tAge="$3"\tGender="$4}' 1.csv
 ID=0   Name=Filipe Age=19  Gender=M
 ID=1   Name=Maria  Age=20  Gender=F
 ID=2   Name=Walter Age=60  Gender=M

On Selenium WebDriver how to get Text from Span Tag

I agree css is better. If you did want to do it via Xpath you could try:

    String kk = wd.findElement(By.xpath(.//*div[@id='customSelect_3']/div/span[@class='selectLabel clear'].getText()))

remove item from array using its name / value

it worked for me..

countries.results= $.grep(countries.results, function (e) { 
      if(!= currentID) {
       return true; 

C++ error: "Array must be initialized with a brace enclosed initializer"

You can't initialize arrays like this:

int cipher[Array_size][Array_size]=0;

The syntax for 2D arrays is:

int cipher[Array_size][Array_size]={{0}};

Note the curly braces on the right hand side of the initialization statement.

for 1D arrays:

int tomultiply[Array_size]={0};

Why is super.super.method(); not allowed in Java?

If you think you are going to be needing the superclass, you could reference it in a variable for that class. For example:

public class Foo
  public int getNumber()
    return 0;

public class SuperFoo extends Foo
  public static Foo superClass = new Foo();
  public int getNumber()
    return 1;

public class UltraFoo extends Foo
  public static void main(String[] args)
    System.out.println(new UltraFoo.getNumber());
    System.out.println(new SuperFoo().getNumber());
    System.out.println(new SuperFoo().superClass.getNumber());
  public int getNumber()
    return 2;

Should print out:


SQL Server 2005 Setting a variable to the result of a select query

This will work for original question asked:

SELECT @Result = COUNT(*)
FROM  TableName
WHERE Condition

How to obtain the last path segment of a URI

Here's a short method to do it:

public static String getLastBitFromUrl(final String url){
    // return url.replaceFirst("[^?]*/(.*?)(?:\\?.*)","$1);" <-- incorrect
    return url.replaceFirst(".*/([^/?]+).*", "$1");

Test Code:

public static void main(final String[] args){




.*/      // find anything up to the last / character
([^/?]+) // find (and capture) all following characters up to the next / or ?
         // the + makes sure that at least 1 character is matched
.*       // find all following characters

$1       // this variable references the saved second group from above
         // I.e. the entire string is replaces with just the portion
         // captured by the parentheses above

Cannot deserialize the current JSON array (e.g. [1,2,3])

To read more than one json tip (array, attribute) I did the following.

var jVariable = JsonConvert.DeserializeObject<YourCommentaryClass>(jsonVariableContent);

change to

var jVariable = JsonConvert.DeserializeObject <List<YourCommentaryClass>>(jsonVariableContent);

Because you cannot see all the bits in the method used in the foreach loop. Example foreach loop

foreach (jsonDonanimSimple Variable in jVariable)

I also received an error in this loop and changed it as follows.

foreach (jsonDonanimSimple Variable in jVariable)

Is it possible to validate the size and type of input=file in html5

    <form  class="upload-form">
        <input class="upload-file" data-max-size="2048" type="file" >
        <input type=submit>
    var fileInput = $('.upload-file');
    var maxSize ='max-size');
            var fileSize = fileInput.get(0).files[0].size; // in bytes
                alert('file size is more then' + maxSize + ' bytes');
                return false;
                alert('file size is correct- '+fileSize+' bytes');
            alert('choose file, please');
            return false;


Parsing JSON array into java.util.List with Gson

Given you start with mapping.get("servers").getAsJsonArray(), if you have access to Guava Streams, you can do the below one-liner:

List<String> servers =
                              .map(je -> je.getAsString())

Note StreamSupport won't be able to work on JsonElement type, so it is insufficient.

How to initialize HashSet values by construction?

In Java 8 I would use:

Set<String> set = Stream.of("a", "b").collect(Collectors.toSet());

This gives you a mutable Set pre-initialized with "a" and "b". Note that while in JDK 8 this does return a HashSet, the specification doesn't guarantee it, and this might change in the future. If you specifically want a HashSet, do this instead:

Set<String> set = Stream.of("a", "b")

How to effectively work with multiple files in Vim

Many answers here! What I use without reinventing the wheel - the most famous plugins (that are not going to die any time soon and are used by many people) to be ultra fast and geeky.

  • ctrlpvim/ctrlp.vim - to find file by name fuzzy search by its location or just its name
  • jlanzarotta/bufexplorer - to browse opened buffers (when you do not remember how many files you opened and modified recently and you do not remember where they are, probably because you searched for them with Ag)
  • rking/ag.vim to search the files with respect to gitignore
  • scrooloose/nerdtree to see the directory structure, lookaround, add/delete/modify files

EDIT: Recently I have been using dyng/ctrlsf.vim to search with contextual view (like Sublime search) and I switched the engine from ag to ripgrep. The performance is outstanding.

EDIT2: Along with CtrlSF you can use mg979/vim-visual-multi, make changes to multiple files at once and then at the end save them in one go.

Show dialog from fragment?

I am a beginner myself and I honestly couldn't find a satisfactory answer that I could understand or implement.

So here's an external link that I really helped me achieved what I wanted. It's very straight forward and easy to follow as well.


I have a MainActivity that hosts a Fragment. I wanted a dialog to appear on top of the layout to ask for user input and then process the input accordingly. See a screenshot

Here's what the onCreateView of my fragment looks

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_home_activity, container, false);

    Button addTransactionBtn = rootView.findViewById(;

    addTransactionBtn.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            Dialog dialog = new Dialog(getActivity());
            dialog.setTitle("Add an Expense");



I hope it will help you

Let me know if there's any confusion. :)

Passing an array as an argument to a function in C

Arrays in C are converted, in most of the cases, to a pointer to the first element of the array itself. And more in detail arrays passed into functions are always converted into pointers.

Here a quote from K&R2nd:

When an array name is passed to a function, what is passed is the location of the initial element. Within the called function, this argument is a local variable, and so an array name parameter is a pointer, that is, a variable containing an address.


void arraytest(int a[])

has the same meaning as writing:

void arraytest(int *a)

So despite you are not writing it explicitly it is as you are passing a pointer and so you are modifying the values in the main.

For more I really suggest reading this.

Moreover, you can find other answers on SO here

How do I run a docker instance from a DockerFile?

Straightforward and easy solution is:

docker build .
=> ....
=> Successfully built a3e628814c67
docker run -p 3000:3000 a3e628814c67

3000 - can be any port

a3e628814c68 - hash result given by success build command

NOTE: you should be within directory that contains Dockerfile.

How can I create a Windows .exe (standalone executable) using Java/Eclipse?

Creating .exe distributions isn't typical for Java. While such wrappers do exist, the normal mode of operation is to create a .jar file.

To create a .jar file from a Java project in Eclipse, use file->export->java->Jar file. This will create an archive with all your classes.

On the command prompt, use invocation like the following:

java -cp myapp.jar

Django CSRF Cookie Not Set

Problem seems that you are not handling GET requests appropriately or directly posting the data without first getting the form.

When you first access the page, client will send GET request, in that case you should send html with appropriate form.

Later, user fills up the form and sends POST request with form data.

Your view should be:

def deposit(request,account_num):
   if request.method == 'POST':
      form_=AccountForm(request.POST or None, instance=account)
      if form.is_valid(): 
          #handle form data
          return HttpResponseRedirect("/history/" + account_num + "/")
         #handle when form not valid
       #handle when request is GET (or not POST)

    return render_to_response('history.html',
                          {'account_form': form},

ORA-01882: timezone region not found

What happens is, that the JDBC client sends the timezone ID to the Server. The server needs to know that zone. You can check with

SELECT DISTINCT tzname FROM V$TIMEZONE_NAMES where tzname like 'Etc%';

I have some db servers which know about 'Etc/UTC' and 'UTC' (tzfile version 18) but others only know 'UTC' (tz version 11).


There is also different behavior on the JDBC client side. Starting with 11.2 the driver will sent the zone IDs if it is "known" to Oracle, whereas before it sent the time offset. The problem with this "sending of known IDs" is, that the client does not check what timezone version/content is present on the server but has its own list.

This is explained in Oracle Support Article [ID 1068063.1].

It seems it also depends on the Client OS, it was more likely that Etc/UTC fails with Ubuntu than RHEL or Windows. I guess this is due to some normalization but I haven't figured out what exactly.

How to initialize List<String> object in Java?

Depending on what kind of List you want to use, something like

List<String> supplierNames = new ArrayList<String>();

should get you going.

List is the interface, ArrayList is one implementation of the List interface. More implementations that may better suit your needs can be found by reading the JavaDocs of the List interface.

C++ template constructor

Here's a workaround.

Make a template subclass B of A. Do the template-argument-independent part of the construction in A's constructor. Do the template-argument-dependent part in B's constructor.

Any easy way to use icons from resources?

in visual studio for, go to the project properties, click Add Resource > Existing File, select your Icon.

in your code: Me.Icon = My.Resources.IconResourceName

How to get JQuery.trigger('click'); to initiate a mouse click

You can't simulate a click event with javascript. jQuery .trigger() function only fires an event named "click" on the element, which you can capture with .on() jQuery method.

Unable to begin a distributed transaction

Apart from the security settings, I had to open some ports on both servers for the transaction to run. I had to open port 59640 but according to the following suggestion, port 135 has to be open.

Setting the selected attribute on a select list using jQuery

$('#select_id option:eq(0)').prop('selected', 'selected');

its good

Nginx subdomain configuration

Another type of solution would be to autogenerate the nginx conf files via Jinja2 templates from ansible. The advantage of this is easy deployment to a cloud environment, and easy to replicate on multiple dev machines

TypeError: 'float' object not iterable

for i in count: means for i in 7:, which won't work. The bit after the in should be of an iterable type, not a number. Try this:

for i in range(count):

ARG or ENV, which one to use in this case?

From Dockerfile reference:

  • The ARG instruction defines a variable that users can pass at build-time to the builder with the docker build command using the --build-arg <varname>=<value> flag.

  • The ENV instruction sets the environment variable <key> to the value <value>.
    The environment variables set using ENV will persist when a container is run from the resulting image.

So if you need build-time customization, ARG is your best choice.
If you need run-time customization (to run the same image with different settings), ENV is well-suited.

If I want to add let's say 20 (a random number) of extensions or any other feature that can be enable|disable

Given the number of combinations involved, using ENV to set those features at runtime is best here.

But you can combine both by:

  • building an image with a specific ARG
  • using that ARG as an ENV

That is, with a Dockerfile including:

ARG var
ENV var=${var}

You can then either build an image with a specific var value at build-time (docker build --build-arg var=xxx), or run a container with a specific runtime value (docker run -e var=yyy)

Printing list elements on separated lines in Python

Sven Marnach's answer is pretty much it, but has one generality issue... It will fail if the list being printed doesn't just contain strings.

So, the more general answer to "How to print out a list with elements separated by newlines"...

print '\n'.join([ str(myelement) for myelement in mylist ])

Then again, the print function approach JBernardo points out is superior. If you can, using the print function instead of the print statement is almost always a good idea.

Image resolution for new iPhone 6 and 6+, @3x support added?

I've tried in a sample project to use standard, @2x and @3x images, and the iPhone 6+ simulator uses the @3x image. So it would seem that there are @3x images to be done (if the simulator actually replicates the device's behavior). But the strange thing is that all devices (simulators) seem to use this @3x image when it's on the project structure, iPhone 4S/iPhone 5 too.
The lack of communication from Apple on a potential @3x structure, while they ask developers to publish their iOS8 apps is quite confusing, especially when seeing those results on simulator.

**Edit from Apple's Website **: Also found this on the "What's new on iOS 8" section on Apple's developer space :

Support for a New Screen Scale The iPhone 6 Plus uses a new Retina HD display with a screen scale of 3.0. To provide the best possible experience on these devices, include new artwork designed for this screen scale. In Xcode 6, asset catalogs can include images at 1x, 2x, and 3x sizes; simply add the new image assets and iOS will choose the correct assets when running on an iPhone 6 Plus. The image loading behavior in iOS also recognizes an @3x suffix.

Still not understanding why all devices seem to load the @3x. Maybe it's because I'm using regular files and not xcassets ? Will try soon.

Edit after further testing : Ok it seems that iOS8 has a talk in this. When testing on an iOS 7.1 iPhone 5 simulator, it uses correctly the @2x image. But when launching the same on iOS 8 it uses the @3x on iPhone 5. Not sure if that's a wanted behavior or a mistake/bug in iOS8 GM or simulators in Xcode 6 though.

Convert Python program to C/C++ code?

Shed Skin is "a (restricted) Python-to-C++ compiler".

How does the FetchMode work in Spring Data JPA

I think that Spring Data ignores the FetchMode. I always use the @NamedEntityGraph and @EntityGraph annotations when working with Spring Data

@NamedEntityGraph(name = "GroupInfo.detail",
  attributeNodes = @NamedAttributeNode("members"))
public class GroupInfo {

  // default fetch mode is lazy.
  List<GroupMember> members = new ArrayList<GroupMember>();


public interface GroupRepository extends CrudRepository<GroupInfo, String> {

  @EntityGraph(value = "GroupInfo.detail", type = EntityGraphType.LOAD)
  GroupInfo getByGroupName(String name);


Check the documentation here

WPF Datagrid set selected row

// In General to Access all rows //

foreach (var item in dataGrid1.Items)
    string str = ((DataRowView)dataGrid1.Items[1]).Row["ColumnName"].ToString();

//To Access Selected Rows //

private void dataGrid1_SelectionChanged(object sender, SelectionChangedEventArgs e)
        string str = ((DataRowView)dataGrid1.SelectedItem).Row["ColumnName"].ToString();
    catch (Exception ex)

JSONException: Value of type java.lang.String cannot be converted to JSONObject

I think the problem may be in the charset that you are trying to use. It is probably best to use UTF-8 instead of iso-8859-1.

Also open whatever file is being used for your InputStream and make sure no special characters were accidentally inserted. Sometimes you have to specifically tell your editor to display hidden / special characters.

fstream won't create a file

You should add fstream::out to open method like this:"test.txt",fstream::out);

More information about fstream flags, check out this link:

HTTP could not register URL http://+:8000/HelloWCF/. Your process does not have access rights to this namespace

Close iis express and all the browsers (if the url was opened in any of the browser). Also open the visual studio IDE in admin mode. This has resolved my issue.

How can I display a modal dialog in Redux that performs asynchronous actions?

Update: React 16.0 introduced portals through ReactDOM.createPortal link

Update: next versions of React (Fiber: probably 16 or 17) will include a method to create portals: ReactDOM.unstable_createPortal() link

Use portals

Dan Abramov answer first part is fine, but involves a lot of boilerplate. As he said, you can also use portals. I'll expand a bit on that idea.

The advantage of a portal is that the popup and the button remain very close into the React tree, with very simple parent/child communication using props: you can easily handle async actions with portals, or let the parent customize the portal.

What is a portal?

A portal permits you to render directly inside document.body an element that is deeply nested in your React tree.

The idea is that for example you render into body the following React tree:

<div className="layout">
  <div className="outside-portal">
      <div className="inside-portal">

And you get as output:

  <div class="layout">
    <div class="outside-portal">
  <div class="inside-portal">

The inside-portal node has been translated inside <body>, instead of its normal, deeply-nested place.

When to use a portal

A portal is particularly helpful for displaying elements that should go on top of your existing React components: popups, dropdowns, suggestions, hotspots

Why use a portal

No z-index problems anymore: a portal permits you to render to <body>. If you want to display a popup or dropdown, this is a really nice idea if you don't want to have to fight against z-index problems. The portal elements get added do document.body in mount order, which means that unless you play with z-index, the default behavior will be to stack portals on top of each others, in mounting order. In practice, it means that you can safely open a popup from inside another popup, and be sure that the 2nd popup will be displayed on top of the first, without having to even think about z-index.

In practice

Most simple: use local React state: if you think, for a simple delete confirmation popup, it's not worth to have the Redux boilerplate, then you can use a portal and it greatly simplifies your code. For such a use case, where the interaction is very local and is actually quite an implementation detail, do you really care about hot-reloading, time-traveling, action logging and all the benefits Redux brings you? Personally, I don't and use local state in this case. The code becomes as simple as:

class DeleteButton extends React.Component {
  static propTypes = {
    onDelete: PropTypes.func.isRequired,

  state = { confirmationPopup: false };

  open = () => {
    this.setState({ confirmationPopup: true });

  close = () => {
    this.setState({ confirmationPopup: false });

  render() {
    return (
      <div className="delete-button">
        <div onClick={() =>}>Delete</div>
        {this.state.confirmationPopup && (
              onCancel={() => this.close()}
              onConfirm={() => {

Simple: you can still use Redux state: if you really want to, you can still use connect to choose whether or not the DeleteConfirmationPopup is shown or not. As the portal remains deeply nested in your React tree, it is very simple to customize the behavior of this portal because your parent can pass props to the portal. If you don't use portals, you usually have to render your popups at the top of your React tree for z-index reasons, and usually have to think about things like "how do I customize the generic DeleteConfirmationPopup I built according to the use case". And usually you'll find quite hacky solutions to this problem, like dispatching an action that contains nested confirm/cancel actions, a translation bundle key, or even worse, a render function (or something else unserializable). You don't have to do that with portals, and can just pass regular props, since DeleteConfirmationPopup is just a child of the DeleteButton


Portals are very useful to simplify your code. I couldn't do without them anymore.

Note that portal implementations can also help you with other useful features like:

  • Accessibility
  • Espace shortcuts to close the portal
  • Handle outside click (close portal or not)
  • Handle link click (close portal or not)
  • React Context made available in portal tree

react-portal or react-modal are nice for popups, modals, and overlays that should be full-screen, generally centered in the middle of the screen.

react-tether is unknown to most React developers, yet it's one of the most useful tools you can find out there. Tether permits you to create portals, but will position automatically the portal, relative to a given target. This is perfect for tooltips, dropdowns, hotspots, helpboxes... If you have ever had any problem with position absolute/relative and z-index, or your dropdown going outside of your viewport, Tether will solve all that for you.

You can, for example, easily implement onboarding hotspots, that expands to a tooltip once clicked:

Onboarding hotspot

Real production code here. Can't be any simpler :)


Edit: just discovered react-gateway which permits to render portals into the node of your choice (not necessarily body)

Edit: it seems react-popper can be a decent alternative to react-tether. PopperJS is a library that only computes an appropriate position for an element, without touching the DOM directly, letting the user choose where and when he wants to put the DOM node, while Tether appends directly to the body.

Edit: there's also react-slot-fill which is interesting and can help solve similar problems by allowing to render an element to a reserved element slot that you put anywhere you want in your tree

How to add hours to current time in python

from datetime import datetime, timedelta

nine_hours_from_now = + timedelta(hours=9)
#datetime.datetime(2012, 12, 3, 23, 24, 31, 774118)

And then use string formatting to get the relevant pieces:

>>> '{:%H:%M:%S}'.format(nine_hours_from_now)

If you're only formatting the datetime then you can use:

>>> format(nine_hours_from_now, '%H:%M:%S')

Or, as @eumiro has pointed out in comments - strftime

Maximum number of rows of CSV data in excel sheet

Using the Excel Text import wizard to import it if it is a text file, like a CSV file, is another option and can be done based on which row number to which row numbers you specify. See: This link

CSS: Truncate table cells, but fit as much as possible

I've been faced the same challenge few days ago. It seems Lucifer Sam found the best solution.

But I noticed you should duplicate content at spacer element. Thought it's not so bad, but I'd like also to apply title popup for clipped text. And it means long text will appear third time in my code.

Here I propose to access title attribute from :after pseudo-element to generate spacer and keep HTML clean.

Works on IE8+, FF, Chrome, Safari, Opera

<table border="1">
    <td class="ellipsis_cell">
      <div title="This cells has more content">
        <span>This cells has more content</span>
    <td class="nowrap">Less content here</td>
.ellipsis_cell > div {
    position: relative;
    overflow: hidden;
    height: 1em;

/* visible content */
.ellipsis_cell > div > span {
    display: block;
    position: absolute; 
    max-width: 100%;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    line-height: 1em;

/* spacer content */
.ellipsis_cell > div:after {
    content: attr(title);
    overflow: hidden;
    height: 0;
    display: block;

ASP.NET MVC Dropdown List From SelectList

Try this, just an example:

u.UserTypeOptions = new SelectList(new[]
        new { ID="1", Name="name1" },
        new { ID="2", Name="name2" },
        new { ID="3", Name="name3" },
    }, "ID", "Name", 1);


u.UserTypeOptions = new SelectList(new List<SelectListItem>
        new SelectListItem { Selected = true, Text = string.Empty, Value = "-1"},
        new SelectListItem { Selected = false, Text = "Homeowner", Value = "2"},
        new SelectListItem { Selected = false, Text = "Contractor", Value = "3"},

Return from a promise then()

When you return something from a then() callback, it's a bit magic. If you return a value, the next then() is called with that value. However, if you return something promise-like, the next then() waits on it, and is only called when that promise settles (succeeds/fails).


How to find the kafka version in linux

go to kafka/libs folder we can see multiple jars search for something similar kafka_2.11- in this case the kafka version is

What is null in Java?

There are two major categories of types in Java: primitive and reference. Variables declared of a primitive type store values; variables declared of a reference type store references.

String x = null;

In this case, the initialization statement declares a variables “x”. “x” stores String reference. It is null here. First of all, null is not a valid object instance, so there is no memory allocated for it. It is simply a value that indicates that the object reference is not currently referring to an object.

How can I create a UIColor from a hex string?

I created a convenience init for that:

extension UIColor {
convenience init(hex: String, alpha: CGFloat)
    let redH = CGFloat(strtoul(hex.substringToIndex(advance(hex.startIndex,2)), nil, 16))
    let greenH = CGFloat(strtoul(hex.substringWithRange(Range<String.Index>(start: advance(hex.startIndex, 2), end: advance(hex.startIndex, 4))), nil, 16))
    let blueH = CGFloat(strtoul(hex.substringFromIndex(advance(hex.startIndex,4)), nil, 16))

    self.init(red: redH/255, green: greenH/255, blue: blueH/255, alpha: alpha)

then you can create an UIColor anywhere in your project just like this:

UIColor(hex: "ffe3c8", alpha: 1)

hope this helps...

Display all items in array using jquery

for (var i = 0; i < array.length; i++) {
    $(".element").append('<span>' + array[i] + '</span>');

Using Gradle to build a jar with dependencies

I use task shadowJar by plugin . com.github.jengelman.gradle.plugins:shadow:5.2.0

Usage just run ./gradlew app::shadowJar result file will be at MyProject/app/build/libs/shadow.jar

top level build.gradle file :

 apply plugin: 'kotlin'

buildscript {
    ext.kotlin_version = '1.3.61'

    repositories {

    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.github.jengelman.gradle.plugins:shadow:5.2.0'

app module level build.gradle file

apply plugin: 'java'
apply plugin: 'kotlin'
apply plugin: 'kotlin-kapt'
apply plugin: 'application'
apply plugin: 'com.github.johnrengelman.shadow'

sourceCompatibility = 1.8

kapt {
    generateStubs = true

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])

    implementation "org.seleniumhq.selenium:selenium-java:4.0.0-alpha-4"
    shadow "org.seleniumhq.selenium:selenium-java:4.0.0-alpha-4"

    implementation project(":module_remote")
    shadow project(":module_remote")

jar {
    exclude 'META-INF/*.SF', 'META-INF/*.DSA', 'META-INF/*.RSA', 'META-INF/*.MF'
    manifest {
                'Main-Class': 'com.github.kolyall.TheApplication',
                'Class-Path': configurations.compile.files.collect { "lib/$" }.join(' ')

shadowJar {
    baseName = 'shadow'
    classifier = ''
    archiveVersion = ''
    mainClassName = 'com.github.kolyall.TheApplication'


Can someone explain __all__ in Python?

It also changes what pydoc will show:

a = "A"
b = "B"
c = "C"

__all__ = ['a', 'b']

a = "A"
b = "B"
c = "C"

$ pydoc module1

Help on module module1:



    a = 'A'
    b = 'B'
    c = 'C'

$ pydoc module2

Help on module module2:



    __all__ = ['a', 'b']
    a = 'A'
    b = 'B'

I declare __all__ in all my modules, as well as underscore internal details, these really help when using things you've never used before in live interpreter sessions.

Cannot deserialize instance of object out of START_ARRAY token in Spring Webservice

I've had a very similar issue using spring-boot-starter-data-redis. To my implementation there was offered a @Bean for RedisTemplate as follows:

public RedisTemplate<String, List<RoutePlantCache>> redisTemplate(RedisConnectionFactory connectionFactory) {
    final RedisTemplate<String, List<RoutePlantCache>> template = new RedisTemplate<>();
    template.setKeySerializer(new StringRedisSerializer());
    template.setValueSerializer(new Jackson2JsonRedisSerializer<>(RoutePlantCache.class));

    // Add some specific configuration here. Key serializers, etc.
    return template;

The fix was to specify an array of RoutePlantCache as following:

template.setValueSerializer(new Jackson2JsonRedisSerializer<>(RoutePlantCache[].class));

Below the exception I had:

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `[...].RoutePlantCache` out of START_ARRAY token
 at [Source: (byte[])"[{ ... },{ ... [truncated 1478 bytes]; line: 1, column: 1]
    at com.fasterxml.jackson.databind.exc.MismatchedInputException.from( ~[jackson-databind-2.11.4.jar:2.11.4]
    at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch( ~[jackson-databind-2.11.4.jar:2.11.4]
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken( ~[jackson-databind-2.11.4.jar:2.11.4]
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken( ~[jackson-databind-2.11.4.jar:2.11.4]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeFromArray( ~[jackson-databind-2.11.4.jar:2.11.4]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther( ~[jackson-databind-2.11.4.jar:2.11.4]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize( ~[jackson-databind-2.11.4.jar:2.11.4]
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose( ~[jackson-databind-2.11.4.jar:2.11.4]
    at com.fasterxml.jackson.databind.ObjectMapper.readValue( ~[jackson-databind-2.11.4.jar:2.11.4]

How to blur background images in Android

You can have a view with Background color as black and set alpha for the view as 0.7 or whatever as per your requirement.

<RelativeLayout xmlns:android=""


Convert decimal to binary in python

You can also use a function from the numpy module

from numpy import binary_repr

which can also handle leading zeros:

Definition:     binary_repr(num, width=None)
    Return the binary representation of the input number as a string.

    This is equivalent to using base_repr with base 2, but about 25x

    For negative numbers, if width is not given, a - sign is added to the
    front. If width is given, the two's complement of the number is
    returned, with respect to that width.

Android How to adjust layout in Full Screen Mode when softkeyboard is visible

Today not working adjustResize on full screen issue is actual for android sdk.

From answers i found:
the solution - but solution has this showing on picture issue :

Than i found the solution and remove the one unnecessary action:


So, see my fixed solution code on Kotlin:

class AndroidBug5497Workaround constructor(val activity: Activity) {

    private val content = activity.findViewById<View>( as FrameLayout

    private val mChildOfContent = content.getChildAt(0)
    private var usableHeightPrevious: Int = 0
    private val contentContainer = activity.findViewById( as ViewGroup
    private val rootView = contentContainer.getChildAt(0)
    private val rootViewLayout = rootView.layoutParams as FrameLayout.LayoutParams

    private val listener = {

    fun addListener() {
        mChildOfContent.apply {


    fun removeListener() {
        mChildOfContent.apply {

    private fun possiblyResizeChildOfContent() {
        val contentAreaOfWindowBounds = Rect()
        val usableHeightNow = contentAreaOfWindowBounds.height()

        if (usableHeightNow != usableHeightPrevious) {
            rootViewLayout.height = usableHeightNow
          , contentAreaOfWindowBounds.right, contentAreaOfWindowBounds.bottom);
            usableHeightPrevious = usableHeightNow

My bug fixing implement code:

 class LeaveDetailActivity : BaseActivity(){

    private val keyBoardBugWorkaround by lazy {

    override fun onCreate(savedInstanceState: Bundle?) {


    override fun onResume() {

    override fun onPause() {

How to center a window on the screen in Tkinter?

You can try to use the methods winfo_screenwidth and winfo_screenheight, which return respectively the width and height (in pixels) of your Tk instance (window), and with some basic math you can center your window:

import tkinter as tk
from PyQt4 import QtGui    # or PySide

def center(toplevel):

    # Tkinter way to find the screen resolution
    # screen_width = toplevel.winfo_screenwidth()
    # screen_height = toplevel.winfo_screenheight()

    # PyQt way to find the screen resolution
    app = QtGui.QApplication([])
    screen_width = app.desktop().screenGeometry().width()
    screen_height = app.desktop().screenGeometry().height()

    size = tuple(int(_) for _ in toplevel.geometry().split('+')[0].split('x'))
    x = screen_width/2 - size[0]/2
    y = screen_height/2 - size[1]/2

    toplevel.geometry("+%d+%d" % (x, y))

if __name__ == '__main__':
    root = tk.Tk()
    root.title("Not centered")

    win = tk.Toplevel(root)


I am calling update_idletasks method before retrieving the width and the height of the window in order to ensure that the values returned are accurate.

Tkinter doesn't see if there are 2 or more monitors extended horizontal or vertical. So, you 'll get the total resolution of all screens together and your window will end-up somewhere in the middle of the screens.

PyQt from the other hand, doesn't see multi-monitors environment either, but it will get only the resolution of the Top-Left monitor (Imagine 4 monitors, 2 up and 2 down making a square). So, it does the work by putting the window on center of that screen. If you don't want to use both, PyQt and Tkinter, maybe it would be better to go with PyQt from start.

jquery equivalent for JSON.stringify

There is no such functionality in jQuery. Use JSON.stringify or alternatively any jQuery plugin with similar functionality (e.g jquery-json).

ORA-01652 Unable to extend temp segment by in tablespace

I encountered the same error message but don't have any access to the table like "dba_free_space" because I am not a dba. I use some previous answers to check available space and I still have a lot of space. However, after reducing the full table scan as many as possible. The problem is solved. My guess is that Oracle uses temp table to store the full table scan data. It the data size exceeds the limit, it will show the error. Hope this helps someone with the same issue

Change keystore password from no password to a non blank password

On my system the password is 'changeit'. On blank if I hit enter then it complains about short password. Hope this helps

enter image description here

pull out p-values and r-squared from a linear regression

You can see the structure of the object returned by summary() by calling str(summary(fit)). Each piece can be accessed using $. The p-value for the F statistic is more easily had from the object returned by anova.

Concisely, you can do this:

rSquared <- summary(fit)$r.squared
pVal <- anova(fit)$'Pr(>F)'[1]

git ahead/behind info between master and branch?

Here's a trick I found to compare two branches and show how many commits each branch is ahead of the other (a more general answer on your question 1):

For local branches: git rev-list --left-right --count master...test-branch

For remote branches: git rev-list --left-right --count origin/master...origin/test-branch

This gives output like the following:

1 7

This output means: "Compared to master, test-branch is 7 commits ahead and 1 commit behind."

You can also compare local branches with remote branches, e.g. origin/master...master to find out how many commits the local master branch is ahead/behind its remote counterpart.

Selecting Multiple Values from a Dropdown List in Google Spreadsheet

To Add to AlexG's answer, a better and enhanced version of multi-select is found in this following link (which I tried and worked as expected):

For general guidance on setting up a script in Google Sheets, see this quickstart guide.

To use this script:

  1. In your Google Sheet, set up data validation for a cell (or cells), using data from a range. In cell validation, do not select 'Reject input'.
  2. Go to Tools > Script editor...
  3. In the script editor, go to File > New > Script file
  4. Name the file and paste in the contents of File > Save.
  5. In the script editor, go to File > New > Html file Name the file dialog.html and paste in the contents of dialog.html. File > Save.
  6. Back in your spreadsheet, you should now have a new menu called 'Scripts'. Refresh the page if necessary.
  7. Select the cell you want to fill with multiple items from your validation range.
  8. Go to Scripts > Multi-select for this cell... and the sidebar should open, showing a checklist of valid items.
  9. Tick the items you want and click the 'Set' button to fill your cell with those selected items, comma separated.

You can leave the script sidebar open. When you select any cell that has validation, click 'Refresh validation' in the script sidebar to bring up that cell's checklist.

The above mentioned steps are taken from this link

Serialize Class containing Dictionary member

You can't serialize a class that implements IDictionary. Check out this link.

Q: Why can't I serialize hashtables?

A: The XmlSerializer cannot process classes implementing the IDictionary interface. This was partly due to schedule constraints and partly due to the fact that a hashtable does not have a counterpart in the XSD type system. The only solution is to implement a custom hashtable that does not implement the IDictionary interface.

So I think you need to create your own version of the Dictionary for this. Check this other question.

Secure hash and salt for PHP passwords

I usually use SHA1 and salt with the user ID (or some other user-specific piece of information), and sometimes I additionally use a constant salt (so I have 2 parts to the salt).

SHA1 is now also considered somewhat compromised, but to a far lesser degree than MD5. By using a salt (any salt), you're preventing the use of a generic rainbow table to attack your hashes (some people have even had success using Google as a sort of rainbow table by searching for the hash). An attacker could conceivably generate a rainbow table using your salt, so that's why you should include a user-specific salt. That way, they will have to generate a rainbow table for each and every record in your system, not just one for your entire system! With that type of salting, even MD5 is decently secure.

How do I format date and time on ssrs report?

=Format(Now(), "MM/dd/yyyy hh:mm tt")


04/12/2013 05:09 PM

How to change the floating label color of TextInputLayout

In the latest version of the support library (23.0.0+), TextInputLayout takes the following attribute in XML to edit the floating label color: android:textColorHint="@color/white"

Create an ArrayList with multiple object types?

You can use Object for storing any type of value for e.g. int, float, String, class objects, or any other java objects, since it is the root of all the class. For e.g.

  1. Declaring a class

    class Person {
    public int personId;
    public String personName;
    public int getPersonId() {
        return personId;
    public void setPersonId(int personId) {
        this.personId = personId;
    public String getPersonName() {
        return personName;
    public void setPersonName(String personName) {
        this.personName = personName;
  2. main function code, which creates the new person object, int, float, and string type, and then is added to the List, and iterated using for loop. Each object is identified, and then the value is printed.

        Person p = new Person();
    List<Object> lstObject = new ArrayList<Object>();
    for (Object obj : lstObject) {
        if (obj.getClass() == String.class) {
            System.out.println("I found a string :- " + obj);
        if (obj.getClass() == Integer.class) {
            System.out.println("I found an int :- " + obj);
        if (obj.getClass() == Float.class) {
            System.out.println("I found a float :- " + obj);
        if (obj.getClass() == Person.class) {
            Person person = (Person) obj;
            System.out.println("I found a person object");
            System.out.println("Person Id :- " + person.getPersonId());
            System.out.println("Person Name :- " + person.getPersonName());

You can find more information on the object class on this link Object in java

Process with an ID #### is not running in visual studio professional 2013 update 3

I had the same problem, and what needed to be done was setup IIS Express properly.

I right clicked on my project Properties => Web (tab) and on Servers: Project URL was already pre-populated and I clicked the button "Create Virtual Directory".

I had just reinstalled (refreshed) windows and the IIS was not setup b/c it was new.

Hope this helps.

jQuery UI autocomplete with JSON

You need to transform the object you are getting back into an array in the format that jQueryUI expects.

You can use $.map to transform the dealers object into that array.

    source: function (request, response) {
        $.getJSON("/example/location/example.json?term=" + request.term, function (data) {
            response($.map(data.dealers, function (value, key) {
                return {
                    label: value,
                    value: key
    minLength: 2,
    delay: 100

Note that when you select an item, the "key" will be placed in the text box. You can change this by tweaking the label and value properties that $.map's callback function return.

Alternatively, if you have access to the server-side code that is generating the JSON, you could change the way the data is returned. As long as the data:

  • Is an array of objects that have a label property, a value property, or both, or
  • Is a simple array of strings

In other words, if you can format the data like this:

[{ value: "1463", label: "dealer 5"}, { value: "269", label: "dealer 6" }]

or this:

["dealer 5", "dealer 6"]

Then your JavaScript becomes much simpler:

    source: "/example/location/example.json"

How can I find non-ASCII characters in MySQL?

Based on the correct answer, but taking into account ASCII control characters as well, the solution that worked for me is this:

SELECT * FROM `table` WHERE NOT `field` REGEXP  "[\\x00-\\xFF]|^$";

It does the same thing: searches for violations of the ASCII range in a column, but lets you search for control characters too, since it uses hexadecimal notation for code points. Since there is no comparison or conversion (unlike @Ollie's answer), this should be significantly faster, too. (Especially if MySQL does early-termination on the regex query, which it definitely should.)

It also avoids returning fields that are zero-length. If you want a slightly-longer version that might perform better, you can use this instead:

SELECT * FROM `table` WHERE `field` <> "" AND NOT `field` REGEXP  "[\\x00-\\xFF]";

It does a separate check for length to avoid zero-length results, without considering them for a regex pass. Depending on the number of zero-length entries you have, this could be significantly faster.

Note that if your default character set is something bizarre where 0x00-0xFF don't map to the same values as ASCII (is there such a character set in existence anywhere?), this would return a false positive. Otherwise, enjoy!

How to check if a String contains only ASCII?

//return is uppercase or lowercase
public boolean isASCIILetter(char c) {
  return (c > 64 && c < 91) || (c > 96 && c < 123);

Double precision floating values in Python?

For some applications you can use Fraction instead of floating-point numbers.

>>> from fractions import Fraction
>>> Fraction(1, 3**54)
Fraction(1, 58149737003040059690390169)

(For other applications, there's decimal, as suggested out by the other responses.)

What exactly do "u" and "r" string flags do, and what are raw string literals?

There's not really any "raw string"; there are raw string literals, which are exactly the string literals marked by an 'r' before the opening quote.

A "raw string literal" is a slightly different syntax for a string literal, in which a backslash, \, is taken as meaning "just a backslash" (except when it comes right before a quote that would otherwise terminate the literal) -- no "escape sequences" to represent newlines, tabs, backspaces, form-feeds, and so on. In normal string literals, each backslash must be doubled up to avoid being taken as the start of an escape sequence.

This syntax variant exists mostly because the syntax of regular expression patterns is heavy with backslashes (but never at the end, so the "except" clause above doesn't matter) and it looks a bit better when you avoid doubling up each of them -- that's all. It also gained some popularity to express native Windows file paths (with backslashes instead of regular slashes like on other platforms), but that's very rarely needed (since normal slashes mostly work fine on Windows too) and imperfect (due to the "except" clause above).

r'...' is a byte string (in Python 2.*), ur'...' is a Unicode string (again, in Python 2.*), and any of the other three kinds of quoting also produces exactly the same types of strings (so for example r'...', r'''...''', r"...", r"""...""" are all byte strings, and so on).

Not sure what you mean by "going back" - there is no intrinsically back and forward directions, because there's no raw string type, it's just an alternative syntax to express perfectly normal string objects, byte or unicode as they may be.

And yes, in Python 2.*, u'...' is of course always distinct from just '...' -- the former is a unicode string, the latter is a byte string. What encoding the literal might be expressed in is a completely orthogonal issue.

E.g., consider (Python 2.6):

>>> sys.getsizeof('ciao')
>>> sys.getsizeof(u'ciao')

The Unicode object of course takes more memory space (very small difference for a very short string, obviously ;-).

ReactJS SyntheticEvent stopPropagation() only works with React events?

It is still one intersting moment:


Use this construction, if your function is wrapped by tag

Git: "please tell me who you are" error

In my case I was missing "e" on the word "email" as Chad stated above but I see its not the case with you. Please hit the following command to see if everything is pulling as expected.

git config -l

Adding an onclicklistener to listview (android)

If your Activity extends ListActivity, you can simply override the OnListItemClick() method like so:

/** {@inheritDoc} */
protected void onListItemClick(ListView l, View v, int pos, long id) {  
    super.onListItemClick(l, v, pos, id);

    // TODO : Logic

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

If you end up with merge conflict and doesn't have anything to commit, but still a merge error is being displayed. After applying all the below mentioned commands,

git reset --hard HEAD
git pull --strategy=theirs remote_branch
git fetch origin
git reset --hard origin

Please remove


File [cut paste to some other location in case of recovery] and then enter any of below command depending on which version you want.

git reset --hard HEAD
git reset --hard origin

Hope that helps!!!

Pass parameter from a batch file to a PowerShell script

When a script is loaded, any parameters that are passed are automatically loaded into a special variables $args. You can reference that in your script without first declaring it.

As an example, create a file called test.ps1 and simply have the variable $args on a line by itself. Invoking the script like this, generates the following output:

PowerShell.exe -File test.ps1 a b c "Easy as one, two, three"
Easy as one, two, three

As a general recommendation, when invoking a script by calling PowerShell directly I would suggest using the -File option rather than implicitly invoking it with the & - it can make the command line a bit cleaner, particularly if you need to deal with nested quotes.

Bootstrap carousel resizing image

The reason why your image is resizing which is because it is fluid. You have two ways to do it:

  1. Either give a fixed dimension to your image using CSS like:

    .carousel-inner > .item > img {
  2. A second way to can do this:

    .carousel {

How to check if a file exists in Ansible?

A note on relative paths to complement the other answers.

When doing infrastructure as code I'm usually using roles and tasks that accept relative paths, specially for files defined in those roles.

Special variables like playbook_dir and role_path are very useful to create the absolute paths needed to test for existence.

Display a table/list data dynamically in MVC3/Razor from a JsonResult?

The normal way of doing it is:

  • You get the users from the database in controller.
  • You send a collection of users to the View
  • In the view to loop the list of users building the list.

You don't need a JsonResult or jQuery for this.

Why won't bundler install JSON gem?

This appears to be a bug in Bundler not recognizing the default gems installed along with ruby 2.x. I still experienced the problem even with the latest version of bundler (1.5.3).

One solution is to simply delete json-1.8.1.gemspec from the default gemspec directory.

rm ~/.rubies/ruby-2.1.0/lib/ruby/gems/2.1.0/specifications/default/json-1.8.1.gemspec

After doing this, bundler should have no problem locating the gem. Note that I am using chruby. If you're using some other ruby manager, you'll have to update your path accordingly.

Set Focus After Last Character in Text Box

This is the easy way to do it. If you're going backwards, just add $("#Prefix").val($("#Prefix").val()); after you set the focus

This is the more proper (cleaner) way:

function SetCaretAtEnd(elem) {
        var elemLen = elem.value.length;
        // For IE Only
        if (document.selection) {
            // Set focus
            // Use IE Ranges
            var oSel = document.selection.createRange();
            // Reset position to 0 & then set at end
            oSel.moveStart('character', -elemLen);
            oSel.moveStart('character', elemLen);
            oSel.moveEnd('character', 0);
        else if (elem.selectionStart || elem.selectionStart == '0') {
            // Firefox/Chrome
            elem.selectionStart = elemLen;
            elem.selectionEnd = elemLen;
        } // if
    } // SetCaretAtEnd()

Python handling socket.error: [Errno 104] Connection reset by peer

There is a way to catch the error directly in the except clause with ConnectionResetError, better to isolate the right error. This example also catches the timeout.

from urllib.request import urlopen 
from socket import timeout

url = "http://......"
    string = urlopen(url, timeout=5).read()
except ConnectionResetError:
    print("==> ConnectionResetError")
except timeout: 
    print("==> Timeout")

Extract matrix column values by matrix column name

> myMatrix <- matrix(1:10, nrow=2)
> rownames(myMatrix) <- c("A", "B")
> colnames(myMatrix) <- c("A", "B", "C", "D", "E")

> myMatrix
  A B C D  E
A 1 3 5 7  9
B 2 4 6 8 10

> myMatrix["A", "A"]
[1] 1

> myMatrix["A", ]
A B C D E 
1 3 5 7 9 

> myMatrix[, "A"]
A B 
1 2 

Sending Arguments To Background Worker?

Even though this is an already answered question, I'd leave another option that IMO is a lot easier to read:

BackgroundWorker worker = new BackgroundWorker();
worker.DoWork += (obj, e) => WorkerDoWork(value, text);

And on the handler method:

private void WorkerDoWork(int value, string text) {

Get real path from URI, Android KitKat new storage access framework

Here is an updated version of Paul Burke's answer. In versions below Android 4.4 (KitKat) we don't have the DocumentsContract class.

In order to work on versions below KitKat create this class:

public class DocumentsContract {
    private static final String DOCUMENT_URIS =
        " " +
        " " +
        " " +

    private static final String PATH_DOCUMENT = "document";
    private static final String TAG = DocumentsContract.class.getSimpleName();

    public static String getDocumentId(Uri documentUri) {
        final List<String> paths = documentUri.getPathSegments();
        if (paths.size() < 2) {
            throw new IllegalArgumentException("Not a document: " + documentUri);

        if (!PATH_DOCUMENT.equals(paths.get(0))) {
            throw new IllegalArgumentException("Not a document: " + documentUri);
        return paths.get(1);

    public static boolean isDocumentUri(Uri uri) {
        final List<String> paths = uri.getPathSegments();
        Logger.v(TAG, "paths[" + paths + "]");
        if (paths.size() < 2) {
            return false;
        if (!PATH_DOCUMENT.equals(paths.get(0))) {
            return false;
        return DOCUMENT_URIS.contains(uri.getAuthority());

Python: Assign Value if None Exists

If you mean a variable at the module level then you can use "globals":

if "var1" not in globals():
    var1 = 4

but the common Python idiom is to initialize it to say None (assuming that it's not an acceptable value) and then testing with if var1 is not None.

How to use range-based for() loop with std::map?

From this paper:

for( type-speci?er-seq simple-declarator : expression ) statement

is syntactically equivalent to

    typedef decltype(expression) C;
    auto&& rng(expression);
    for (auto begin(std::For<C>::begin(rng)), end(std::For<C>::end(rng)); begin != end; ++ begin) {
        type-speci?er-seq simple-declarator(*begin);

So you can clearly see that what is abc in your case will be std::pair<key_type, value_type >. So for printing you can do access each element by abc.first and abc.second

Can I load a UIImage from a URL?

If you're really, absolutely positively sure that the NSURL is a file url, i.e. [url isFileURL] is guaranteed to return true in your case, then you can simply use:

[UIImage imageWithContentsOfFile:url.path]

presenting ViewController with NavigationViewController swift

My navigation bar was not showing, so I have used the following method in Swift 2 iOS 9

let viewController = self.storyboard?.instantiateViewControllerWithIdentifier("Dashboard") as! Dashboard

// Creating a navigation controller with viewController at the root of the navigation stack.
let navController = UINavigationController(rootViewController: viewController)
self.presentViewController(navController, animated:true, completion: nil)

Javascript array declaration: new Array(), new Array(3), ['a', 'b', 'c'] create arrays that behave differently

Arrays in JS have two types of properties:

Regular elements and associative properties (which are nothing but objects)

When you define a = new Array(), you are defining an empty array. Note that there are no associative objects yet

When you define b = new Array(2), you are defining an array with two undefined locations.

In both your examples of 'a' and 'b', you are adding associative properties i.e. objects to these arrays.

console.log (a) or console.log(b) prints the array elements i.e. [] and [undefined, undefined] respectively. But since a1/a2 and b1/b2 are associative objects inside their arrays, they can be logged only by console.log(a.a1, a.a2) kind of syntax

Junit - run set up method once

JUnit 5 now has a @BeforeAll annotation:

Denotes that the annotated method should be executed before all @Test methods in the current class or class hierarchy; analogous to JUnit 4’s @BeforeClass. Such methods must be static.

The lifecycle annotations of JUnit 5 seem to have finally gotten it right! You can guess which annotations available without even looking (e.g. @BeforeEach @AfterAll)

Fatal error: [] operator not supported for strings

Such behavior is described in Migrating from PHP 7.0.x to PHP 7.1.x/

The empty index operator is not supported for strings anymore Applying the empty index operator to a string (e.g. $str[] = $x) throws a fatal error instead of converting silently to array.

In my case it was a mere initialization. I fixed it by replacing $foo='' with $foo=[].


What is git fast-forwarding?

In Git, to "fast forward" means to update the HEAD pointer in such a way that its new value is a direct descendant of the prior value. In other words, the prior value is a parent, or grandparent, or grandgrandparent, ...

Fast forwarding is not possible when the new HEAD is in a diverged state relative to the stream you want to integrate. For instance, you are on master and have local commits, and git fetch has brought new upstream commits into origin/master. The branch now diverges from its upstream and cannot be fast forwarded: your master HEAD commit is not an ancestor of origin/master HEAD. To simply reset master to the value of origin/master would discard your local commits. The situation requires a rebase or merge.

If your local master has no changes, then it can be fast-forwarded: simply updated to point to the same commit as the latestorigin/master. Usually, no special steps are needed to do fast-forwarding; it is done by merge or rebase in the situation when there are no local commits.

Is it ok to assume that fast-forward means all commits are replayed on the target branch and the HEAD is set to the last commit on that branch?

No, that is called rebasing, of which fast-forwarding is a special case when there are no commits to be replayed (and the target branch has new commits, and the history of the target branch has not been rewritten, so that all the commits on the target branch have the current one as their ancestor.)

Checking if object is empty, works with ng-show but not from controller?

Or, if using lo-dash: _.empty(value).

"Checks if value is empty. Arrays, strings, or arguments objects with a length of 0 and objects with no own enumerable properties are considered "empty"."

React Native Border Radius with background color

Apply the below line of code :

  style={{ height: 40, width: "95%", borderColor: 'gray', borderWidth: 2, borderRadius: 20,  marginBottom: 20, fontSize: 18, backgroundColor: '#68a0cf' }}
  // Adding hint in TextInput using Placeholder option.
  placeholder=" Enter Your First Name"
  // Making the Under line Transparent.