Programs & Examples On #Tmenuitem

tmenuitem is a non visual VCL component describing the properties of an item in a menu. It is defined in the Menus.pas unit.

Pentaho Data Integration SQL connection

Above answers were helpful, but for unknown reasons they did not seem to work. So if you have already installed MySql workbench on your system, instead of downloading the jar files and struggling with the correct version just go to

C:\Program Files (x86)\MySQL\Connector J 8.0

and copy mysql-connector-java-8.0.12 (does not matter what version it is) the jar file in that location and paste it to C:\Program Files\pentaho\design-tools\data-integration\lib

Flask at first run: Do not use the development server in a production environment

The official tutorial discusses deploying an app to production. One option is to use Waitress, a production WSGI server. Other servers include Gunicorn and uWSGI.

When running publicly rather than in development, you should not use the built-in development server (flask run). The development server is provided by Werkzeug for convenience, but is not designed to be particularly efficient, stable, or secure.

Instead, use a production WSGI server. For example, to use Waitress, first install it in the virtual environment:

$ pip install waitress

You need to tell Waitress about your application, but it doesn’t use FLASK_APP like flask run does. You need to tell it to import and call the application factory to get an application object.

$ waitress-serve --call 'flaskr:create_app'
Serving on

Or you can use waitress.serve() in the code instead of using the CLI command.

from flask import Flask

app = Flask(__name__)

def index():
    return "<h1>Hello!</h1>"

if __name__ == "__main__":
    from waitress import serve
    serve(app, host="", port=8080)
$ python

Script to get the HTTP status code of a list of urls?

wget -S -i *file* will get you the headers from each url in a file.

Filter though grep for the status code specifically.

Is it possible to change the speed of HTML's <marquee> tag?

<marquee behavior=scroll direction="left" scrollamount="5">Your message here</marquee>

scrollamount controls the speed of text: higher the value higher is the scrolling speed

What MySQL data type should be used for Latitude/Longitude with 8 decimal places?

MySQL now has support for spatial data types since this question was asked. So the the current accepted answer is not wrong, but if you're looking for additional functionality like finding all points within a given polygon then use POINT data type.

Checkout the Mysql Docs on Geospatial data types and the spatial analysis functions

Select from multiple tables without a join?

If your question was this -- Select ename, dname FROM emp, dept without using joins..

Then, I would do this...

SELECT ename, (SELECT dname 
FROM dept
WHERE dept.deptno=emp.deptno)dname


---------- --------------

---------- --------------

14 rows selected.

How can I debug javascript on Android?


  1. open the page that you want to debug
  2. while on that page, in the address bar of a stock Android browser, type:


    (Note nothing happens, but some new options have been enabled.)

Works on the devices I have tried. Read more on Android browser's about:debug, what do those settings do?

Edit: What also helps to retrieve more information like line number is to add this code to your script:

window.onerror = function (message, url, lineNo){
    console.log('Error: ' + message + '\n' + 'Line Number: ' + lineNo);
    return true;

Getting HTTP code in PHP using curl

function getStatusCode()
    $url = '';
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_HEADER, true);    // we want headers
    curl_setopt($ch, CURLOPT_NOBODY, true);    // we don't need body
    curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
    curl_setopt($ch, CURLOPT_TIMEOUT,10);
    $output = curl_exec($ch);
    $httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

    return  $httpcode;

Why specify @charset "UTF-8"; in your CSS file?

If you're putting a <meta> tag in your css files, you're doing something wrong. The <meta> tag belongs in your html files, and tells the browser how the html is encoded, it doesn't say anything about the css, which is a separate file. You could conceivably have completely different encodings for your html and css, although I can't imagine this would be a good idea.

Get clicked item and its position in RecyclerView

Based on the link: Why doesn't RecyclerView have onItemClickListener()? and How RecyclerView is different from Listview?, and also @Duncan's general idea, I give my solution here:

  • Define one interface RecyclerViewClickListener for a passing message from the adapter to Activity/Fragment:

      public interface RecyclerViewClickListener {
          public void recyclerViewListClicked(View v, int position);
  • In Activity/Fragment implement the interface, and also pass listener to adapter:

      public void recyclerViewListClicked(View v, int position){... ...}
      //set up adapter and pass clicked listener this
      myAdapter = new MyRecyclerViewAdapter(context, this);
  • In Adapter and ViewHolder:

      public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ItemViewHolder> {
         ... ... 
         private Context context;
         private static RecyclerViewClickListener itemListener;
         public MyRecyclerViewAdapter(Context context, RecyclerViewClickListener itemListener) {
             this.context = context;
             this.itemListener = itemListener;
             ... ...
         //ViewHolder class implement OnClickListener, 
         //set clicklistener to itemView and, 
         //send message back to Activity/Fragment 
         public static class ItemViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
             ... ...
             public ItemViewHolder(View convertView) {
                 ... ...
             public void onClick(View v) {
                 itemListener.recyclerViewListClicked(v, this.getPosition());     

After testing, it works fine.


Since API 22, RecyclerView.ViewHolder.getPosition() is deprecated, so instead with getLayoutPosition().

virtualenvwrapper and Python 3

I added export VIRTUALENV_PYTHON=/usr/bin/python3 to my ~/.bashrc like this:

export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENV_PYTHON=/usr/bin/python3
source /usr/local/bin/

then run source .bashrc

and you can specify the python version for each new env mkvirtualenv --python=python2 env_name

Is there a Python equivalent of the C# null-coalescing operator?

The two functions below I have found to be very useful when dealing with many variable testing cases.

def nz(value, none_value, strict=True):
    ''' This function is named after an old VBA function. It returns a default
        value if the passed in value is None. If strict is False it will
        treat an empty string as None as well.

        x = None
        --> "hello"
        --> ""
        y = ""   
        --> ""
        nz(y,"hello", False)
        --> "hello" '''

    if value is None and strict:
        return_val = none_value
    elif strict and value is not None:
        return_val = value
    elif not strict and not is_not_null(value):
        return_val = none_value
        return_val = value
    return return_val 

def is_not_null(value):
    ''' test for None and empty string '''
    return value is not None and len(str(value)) > 0

SecurityException: Permission denied (missing INTERNET permission?)

I spend hours looking for solution to this problem and none of the solution in the answers worked. Then I found out that I accidentally added a space during autocomplete between android.permission.INTERNET and "

In Python script, how do I set PYTHONPATH?

If you put sys.path.append('dir/to/path') without check it is already added, you could generate a long list in sys.path. For that, I recommend this:

import sys
import os # if you want this directory

    sys.path.index('/dir/path') # Or os.getcwd() for this directory
except ValueError:
    sys.path.append('/dir/path') # Or os.getcwd() for this directory

How to use Angular4 to set focus by element id


import { Component, ElementRef, ViewChild, AfterViewInit} from '@angular/core';

@ViewChild('input1', {static: false}) inputEl: ElementRef;
ngAfterViewInit() {
   setTimeout(() => this.inputEl.nativeElement.focus());


<input type="text" #input1>

Find if listA contains any elements not in listB

You can do it in a single line

var res = listA.Where(n => !listB.Contains(n));

This is not the fastest way to do it: in case listB is relatively long, this should be faster:

var setB = new HashSet(listB);
var res = listA.Where(n => !setB.Contains(n));

How to run a class from Jar which is not the Main-Class in its Manifest file

You can create your jar without Main-Class in its Manifest file. Then :

java -cp MyJar.jar com.mycomp.myproj.dir2.MainClass2 /home/myhome/ /home/myhome/input.txt

Counting array elements in Python



if you want to be oopy; "len(myArray)" is a lot easier to type! :)

How to connect to SQL Server from another computer?

I'll edit my previous answer based on further info supplied. You can clearely ping the remote computer as you can use terminal services.

I've a feeling that port 1433 is being blocked by a firewall, hence your trouble. See TCP Ports Needed for Communication to SQL Server Through a Firewall by Microsoft.

Try using this application to ping your servers ip address and port 1433.

tcping your.server.ip.address 1433

And see if you get a "Port is open" response from tcping.

Ok, next to try is to check SQL Server. RDP onto the SQL Server computer. Start SSMS. Connect to the database. In object explorer (usually docked on the left) right click on the server and click properties.

alt text

Goto the Connections settings and make sure "Allow remote connections to this server" is ticket.

alt text

PHP upload image

The code overlooks calling the function move_uploaded_file() which would check whether the indicated file is valid for uploading.

You may wish to review a simple example at:

How to get user's high resolution profile picture on Twitter?

for me the "workaround" solution was to remove the "_normal" from the end of the string

Check it out below:

how can I set visible back to true in jquery

Using ASP.NET's visible="false" property will set the visibility attribute where as I think when you call show() in jQuery it modifies the display attribute of the CSS style.

So doing the latter won't rectify the former.

You need to do this:

$("#test1").attr("visibility", "visible");

How to set thymeleaf th:field value from other variable

The correct approach is to use preprocessing

For example


How do I enable MSDTC on SQL Server?

MSDTC must be enabled on both systems, both server and client.
Also, make sure that there isn't a firewall between the systems that blocks RPC.
DTCTest is a nice litt app that helps you to troubleshoot any other problems.

Can I add extension methods to an existing static class?

As for extension methods, extension methods themselves are static; but they are invoked as if they are instance methods. Since a static class is not instantiable, you would never have an instance of the class to invoke an extension method from. For this reason the compiler does not allow extension methods to be defined for static classes.

Mr. Obnoxious wrote: "As any advanced .NET developer knows, new T() is slow because it generates a call to System.Activator which uses reflection to get the default constructor before calling it".

New() is compiled to the IL "newobj" instruction if the type is known at compile time. Newobj takes a constructor for direct invocation. Calls to System.Activator.CreateInstance() compile to the IL "call" instruction to invoke System.Activator.CreateInstance(). New() when used against generic types will result in a call to System.Activator.CreateInstance(). The post by Mr. Obnoxious was unclear on this point... and well, obnoxious.

This code:

System.Collections.ArrayList _al = new System.Collections.ArrayList();
System.Collections.ArrayList _al2 = (System.Collections.ArrayList)System.Activator.CreateInstance(typeof(System.Collections.ArrayList));

produces this IL:

  .locals init ([0] class [mscorlib]System.Collections.ArrayList _al,
           [1] class [mscorlib]System.Collections.ArrayList _al2)
  IL_0001:  newobj     instance void [mscorlib]System.Collections.ArrayList::.ctor()
  IL_0006:  stloc.0
  IL_0007:  ldtoken    [mscorlib]System.Collections.ArrayList
  IL_000c:  call       class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
  IL_0011:  call       object [mscorlib]System.Activator::CreateInstance(class [mscorlib]System.Type)
  IL_0016:  castclass  [mscorlib]System.Collections.ArrayList
  IL_001b:  stloc.1

alternative to "!is.null()" in R

The shiny package provides the convenient functions validate() and need() for checking that variables are both available and valid. need() evaluates an expression. If the expression is not valid, then an error message is returned. If the expression is valid, NULL is returned. One can use this to check if a variable is valid. See ?need for more information.

I suggest defining a function like this:

is.valid <- function(x) {
  is.null(need(x, message = FALSE))  

This function is.valid() will return FALSE if x is FALSE, NULL, NA, NaN, an empty string "", an empty atomic vector, a vector containing only missing values, a logical vector containing only FALSE, or an object of class try-error. In all other cases, it returns TRUE.

That means, need() (and is.valid()) covers a really broad range of failure cases. Instead of writing:

if (!is.null(x) && ! && !is.nan(x)) {

one can write simply:

if (is.valid(x)) {

With the check for class try-error, it can even be used in conjunction with a try() block to silently catch errors: (see

bad = try(1 + "1", silent = TRUE)
if (is.valid(bad)) {

What is the difference between an annotated and unannotated tag?


The difference between the commands is that one provides you with a tag message while the other doesn't. An annotated tag has a message that can be displayed with git-show(1), while a tag without annotations is just a named pointer to a commit.

More About Lightweight Tags

According to the documentation: "To create a lightweight tag, don’t supply any of the -a, -s, or -m options, just provide a tag name". There are also some different options to write a message on annotated tags:

  • When you use git tag <tagname>, Git will create a tag at the current revision but will not prompt you for an annotation. It will be tagged without a message (this is a lightweight tag).
  • When you use git tag -a <tagname>, Git will prompt you for an annotation unless you have also used the -m flag to provide a message.
  • When you use git tag -a -m <msg> <tagname>, Git will tag the commit and annotate it with the provided message.
  • When you use git tag -m <msg> <tagname>, Git will behave as if you passed the -a flag for annotation and use the provided message.

Basically, it just amounts to whether you want the tag to have an annotation and some other information associated with it or not.

The character encoding of the plain text document was not declared - mootool script

In my case in ASP MVC it was a method in controller that was returning null to View because of a wrong if statement.

if (condition)
    return null;

Condition fixed and I returned View, Problem fixed. There was nothing with encoding but I don't know why that was my error.

return View(result); // result is View's model

How to convert date format to milliseconds?


this is for set milliseconds in date

long milli = date.getTime();

This is for get time in milliseconds.

Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT

How do I read the source code of shell commands?

Direct links to source for some popular programs in coreutils:

Full list here.

Remove style attribute from HTML tags

You could handle it client side, the easiest would be with jQuery. Something like:

$("#tinyMce p").removeAttr("style");

What is the path that Django uses for locating and loading templates?

basically BASE_DIR is your django project directory, same dir where is.

            'BACKEND': 'django.template.backends.django.DjangoTemplates',
            'DIRS': [os.path.join(BASE_DIR, 'templates')],
            'APP_DIRS': True,
            'OPTIONS': {
                'context_processors': [

How to resize JLabel ImageIcon?

I agree this code works, to size an ImageIcon from a file for display while keeping the aspect ratio I have used the below.

 * source File of image, maxHeight pixels of height available, maxWidth pixels of width available
 * @return an ImageIcon for adding to a label

public ImageIcon rescaleImage(File source,int maxHeight, int maxWidth)
    int newHeight = 0, newWidth = 0;        // Variables for the new height and width
    int priorHeight = 0, priorWidth = 0;
    BufferedImage image = null;
    ImageIcon sizeImage;

    try {
            image =;        // get the image
    } catch (Exception e) {

            System.out.println("Picture upload attempted & failed");

    sizeImage = new ImageIcon(image);

    if(sizeImage != null)
        priorHeight = sizeImage.getIconHeight(); 
        priorWidth = sizeImage.getIconWidth();

    // Calculate the correct new height and width
    if((float)priorHeight/(float)priorWidth > (float)maxHeight/(float)maxWidth)
        newHeight = maxHeight;
        newWidth = (int)(((float)priorWidth/(float)priorHeight)*(float)newHeight);
        newWidth = maxWidth;
        newHeight = (int)(((float)priorHeight/(float)priorWidth)*(float)newWidth);

    // Resize the image

    // 1. Create a new Buffered Image and Graphic2D object
    BufferedImage resizedImg = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
    Graphics2D g2 = resizedImg.createGraphics();

    // 2. Use the Graphic object to draw a new image to the image in the buffer
    g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
    g2.drawImage(image, 0, 0, newWidth, newHeight, null);

    // 3. Convert the buffered image into an ImageIcon for return
    return (new ImageIcon(resizedImg));

What are good grep tools for Windows?

It's been a couple of years since you asked the question, but I'd recommend AstroGrep (

It's free, open source, and has a simple interface. I use it to search code all the time.

How do I draw a set of vertical lines in gnuplot?

You can use the grid feature for the second unused axis x2, which is the most natural way of drawing a set of regular spaced lines.

set grid x2tics
set x2tics 10 format "" scale 0

In general, the grid is drawn at the same position as the tics on the axis. In case the position of the lines does not correspond to the tics position, gnuplot provides an additional set of tics, called x2tics. format "" and scale 0 hides the x2tics so you only see the grid lines.

You can style the lines as usual with linewith, linecolor.

How to smooth a curve in the right way?

Fitting a moving average to your data would smooth out the noise, see this this answer for how to do that.

If you'd like to use LOWESS to fit your data (it's similar to a moving average but more sophisticated), you can do that using the statsmodels library:

import numpy as np
import pylab as plt
import statsmodels.api as sm

x = np.linspace(0,2*np.pi,100)
y = np.sin(x) + np.random.random(100) * 0.2
lowess = sm.nonparametric.lowess(y, x, frac=0.1)

plt.plot(x, y, '+')
plt.plot(lowess[:, 0], lowess[:, 1])

Finally, if you know the functional form of your signal, you could fit a curve to your data, which would probably be the best thing to do.

Test if a string contains a word in PHP?

If you wanna find just the word like 'are' in "How are you?" and not like 'are' in 'hare'

$word=" are ";
$str="How are you?";
if(strpos($word,$str) !== false){
echo 1;

Window vs Page vs UserControl for WPF navigation?

We usually use One Main Window for the application and other windows can be used in situations like when you need popups because instead of using popup controls in XAML which are not visible we can use a Window that is visible at design time so that'll be easy to work with

on the other hand we use many pages to navigate from one screen to another like User management screen to Order Screen etc In the main Window we can use Frame control for navigation like below XAML

    <Frame Name="mainWinFrame" NavigationUIVisibility="Hidden"  ButtonBase.Click="mainWinFrame_Click">


     private void mainWinFrame_Click(object sender, RoutedEventArgs e)
            if (e.OriginalSource is Button)
                Button btn = (Button)e.OriginalSource;

                if ((btn.CommandParameter != null) && (btn.CommandParameter.Equals("Order")))

        catch (Exception ex)
            MessageBox.Show(ex.Message, "Error");

That's one way of doing it We can also use a Tab Control instead of Fram and Add pages to it using a Dictionary while adding new page check if the control already exists then only navigate otherwise add and navigate. I hope that'll help someone

Java decimal formatting using String.format?

java.text.NumberFormat is probably what you want.

Check if number is decimal

is_numeric returns true for decimals and integers. So if your user lazily enters 1 instead of 1.00 it will still return true:

echo is_numeric(1); // true
echo is_numeric(1.00); // true

You may wish to convert the integer to a decimal with PHP, or let your database do it for you.

how to find 2d array size in c++

#include <bits/stdc++.h>
using namespace std;

int main(int argc, char const *argv[])
    int arr[6][5] = {
    int rows = sizeof(arr)/sizeof(arr[0]);
    int cols = sizeof(arr[0])/sizeof(arr[0][0]);
    cout<<rows<<" "<<cols<<endl;
    return 0;

Output: 6 5

Checking during array iteration, if the current element is the last element

$myarray = array(
  'test1' => 'foo',
  'test2' => 'bar',
  'test3' => 'baz',
  'test4' => 'waldo'

$myarray2 = array(

// Get the last array_key
$last = array_pop(array_keys($myarray));
foreach($myarray as $key => $value) {
  if($key != $last) {
    echo "$key -> $value\n";

// Get the last array_key
$last = array_pop(array_keys($myarray2));
foreach($myarray2 as $key => $value) {
  if($key != $last) {
    echo "$key -> $value\n";

Since array_pop works on the temporary array created by array_keys it doesn't modify the original array at all.

$ php test.php
test1 -> foo
test2 -> bar
test3 -> baz
0 -> foo
1 -> bar
2 -> baz

This Handler class should be static or leaks might occur: IncomingHandler

This way worked well for me, keeps code clean by keeping where you handle the message in its own inner class.

The handler you wish to use

Handler mIncomingHandler = new Handler(new IncomingHandlerCallback());

The inner class

class IncomingHandlerCallback implements Handler.Callback{

        public boolean handleMessage(Message message) {

            // Handle message code

            return true;

Upload a file to Amazon S3 with NodeJS

Uploading a file to AWS s3 and sending the url in response for accessing the file.

Multer is a node.js middleware for handling multipart/form-data, which is primarily used for uploading files. It is written on top of busboy for maximum efficiency. check this npm module here.

When you are sending the request, make sure the headers, have Content-Type is multipart/form-data. We are sending the file location in the response, which will give the url, but if you want to access that url, make the bucket public or else you will not be able to access it.


const express = require('express');
const router = express.Router();
const AWS = require('aws-sdk');
const multer = require('multer');
const storage = multer.memoryStorage()
const upload = multer({storage: storage});

const s3Client = new AWS.S3({
    accessKeyId: 'your_access_key_id',
    secretAccessKey: 'your_secret_access_id',
    region :'ur region'

const uploadParams = {
         Bucket: 'ur_bucket_name', 
         Key: '', // pass key
         Body: null, // pass file body
};'/api/file/upload', upload.single("file"),(req,res) => {
    const params = uploadParams;

    uploadParams.Key = req.file.originalname;
    uploadParams.Body = req.file.buffer;

    s3Client.upload(params, (err, data) => {
        if (err) {
            res.status(500).json({error:"Error -> " + err});
        res.json({message: 'File uploaded successfully','filename': 
        req.file.originalname, 'location': data.Location});

module.exports = router;


const express = require('express');
const app = express();

const router = require('./app/routers/upload.router.js');
app.use('/', router);

// Create a Server
  const server = app.listen(8080, () => {
  console.log("App listening at 8080"); 

How to automatically generate N "distinct" colors?

I would try to fix saturation and lumination to maximum and focus on hue only. As I see it, H can go from 0 to 255 and then wraps around. Now if you wanted two contrasting colours you would take the opposite sides of this ring, i.e. 0 and 128. If you wanted 4 colours, you would take some separated by 1/4 of the 256 length of the circle, i.e. 0, 64,128,192. And of course, as others suggested when you need N colours, you could just separate them by 256/N.

What I would add to this idea is to use a reversed representation of a binary number to form this sequence. Look at this:

0 = 00000000  after reversal is 00000000 = 0
1 = 00000001  after reversal is 10000000 = 128
2 = 00000010  after reversal is 01000000 = 64
3 = 00000011  after reversal is 11000000 = 192

... this way if you need N different colours you could just take first N numbers, reverse them, and you get as much distant points as possible (for N being power of two) while at the same time preserving that each prefix of the sequence differs a lot.

This was an important goal in my use case, as I had a chart where colors were sorted by area covered by this colour. I wanted the largest areas of the chart to have large contrast, and I was ok with some small areas to have colours similar to those from top 10, as it was obvious for the reader which one is which one by just observing the area.

Print execution time of a shell command

Don't forget that there is a difference between bash's builtin time (which should be called by default when you do time command) and /usr/bin/time (which should require you to call it by its full path).

The builtin time always prints to stderr, but /usr/bin/time will allow you to send time's output to a specific file, so you do not interfere with the executed command's stderr stream. Also, /usr/bin/time's format is configurable on the command line or by the environment variable TIME, whereas bash's builtin time format is only configured by the TIMEFORMAT environment variable.

$ time factor 1234567889234567891 # builtin
1234567889234567891: 142662263 8653780357

real    0m3.194s
user    0m1.596s
sys 0m0.004s
$ /usr/bin/time factor 1234567889234567891
1234567889234567891: 142662263 8653780357
1.54user 0.00system 0:02.69elapsed 57%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+215minor)pagefaults 0swaps
$ /usr/bin/time -o timed factor 1234567889234567891 # log to file `timed`
1234567889234567891: 142662263 8653780357
$ cat timed
1.56user 0.02system 0:02.49elapsed 63%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+217minor)pagefaults 0swaps

How do I debug "Error: spawn ENOENT" on node.js?

I was getting this error when trying to debug a node.js program from within VS Code editor on a Debian Linux system. I noticed the same thing worked OK on Windows. The solutions previously given here weren't much help because I hadn't written any "spawn" commands. The offending code was presumably written by Microsoft and hidden under the hood of the VS Code program.

Next I noticed that node.js is called node on Windows but on Debian (and presumably on Debian-based systems such as Ubuntu) it's called nodejs. So I created an alias - from a root terminal, I ran

ln -s /usr/bin/nodejs /usr/local/bin/node

and this solved the problem. The same or a similar procedure will presumably work in other cases where your node.js is called nodejs but you're running a program which expects it to be called node, or vice-versa.

Method call if not null in C#

Maybe not better but in my opinion more readable is to create an extension method

public static bool IsNull(this object obj) {
 return obj == null;

Crystal Reports for VS2012 - VS2013 - VS2015 - VS2017 - VS2019

This post is right from SAP on Sep 20, 2012.

In short, they are still working on a release of Crystal Reports that will support VS2012 (including support for Windows 8) It will come in the form of a service pack release that updates the version currently supporting VS2010. At that time they will drop 2010/2012 from the name and simply call it Crystal Reports Developer.

If you want to download that version you can find it here.

Further, service packs etc. when released can be found here.

I would also add that I am currently using Visual Studio 2012. As long as you don't edit existing reports they continue to compile and work fine. Even on Windows 8. When I need to modify a report I can still open the project with VS2010, do my work, save my changes, and then switch back to 2012. It's a little bit of a pain but the ability for VS2010 and VS2012 to co-exist is nice in this regard. I'm also using TFS2012 and so far it hasn't had a problem with me modifying files in 2010 on a "2012" solution.

How to throw std::exceptions with variable messages?

Here is my solution:

#include <stdexcept>
#include <sstream>

class Formatter
    Formatter() {}
    ~Formatter() {}

    template <typename Type>
    Formatter & operator << (const Type & value)
        stream_ << value;
        return *this;

    std::string str() const         { return stream_.str(); }
    operator std::string () const   { return stream_.str(); }

    enum ConvertToString 
    std::string operator >> (ConvertToString) { return stream_.str(); }

    std::stringstream stream_;

    Formatter(const Formatter &);
    Formatter & operator = (Formatter &);


throw std::runtime_error(Formatter() << foo << 13 << ", bar" << myData);   // implicitly cast to std::string
throw std::runtime_error(Formatter() << foo << 13 << ", bar" << myData >> Formatter::to_str);    // explicitly cast to std::string

How to show MessageBox on

You could just simply write but you have to use JavaScript regardless.

Page.ClientScript.RegisterStartupScript(Page.GetType(), "Message Box", "<script language = 'javascript'>alert('dd')</script>");

How to change legend title in ggplot

Adding this to the mix, for when you have changed the colors. This also worked for me in a qplot with two discrete variables:

p+ scale_fill_manual(values = Main_parties_color, name = "Main Parties")

Reading a plain text file in Java

I documented 15 ways to read a file in Java and then tested them for speed with various file sizes - from 1 KB to 1 GB and here are the top three ways to do this:

  1. java.nio.file.Files.readAllBytes()

    Tested to work in Java 7, 8, and 9.

    import java.nio.file.Files;
    public class ReadFile_Files_ReadAllBytes {
      public static void main(String [] pArgs) throws IOException {
        String fileName = "c:\\temp\\sample-10KB.txt";
        File file = new File(fileName);
        byte [] fileBytes = Files.readAllBytes(file.toPath());
        char singleChar;
        for(byte b : fileBytes) {
          singleChar = (char) b;

    Tested to work in Java 7, 8, 9.

    public class ReadFile_BufferedReader_ReadLine {
      public static void main(String [] args) throws IOException {
        String fileName = "c:\\temp\\sample-10KB.txt";
        FileReader fileReader = new FileReader(fileName);
        try (BufferedReader bufferedReader = new BufferedReader(fileReader)) {
          String line;
          while((line = bufferedReader.readLine()) != null) {
  3. java.nio.file.Files.lines()

    This was tested to work in Java 8 and 9 but won't work in Java 7 because of the lambda expression requirement.

    import java.nio.file.Files;
    public class ReadFile_Files_Lines {
      public static void main(String[] pArgs) throws IOException {
        String fileName = "c:\\temp\\sample-10KB.txt";
        File file = new File(fileName);
        try (Stream linesStream = Files.lines(file.toPath())) {
          linesStream.forEach(line -> {

How do I do an initial push to a remote repository with Git?

On server:

mkdir my_project.git
cd my_project.git
git --bare init

On client:

mkdir my_project
cd my_project
touch .gitignore
git init
git add .
git commit -m "Initial commit"
git remote add origin [email protected]:/path/to/my_project.git
git push origin master

Note that when you add the origin, there are several formats and schemas you could use. I recommend you see what your hosting service provides.

Get bitcoin historical data

I have written a java example for this case:

Use library to retrieve JSONObjects and JSONArrays. The example below uses's data which can be obtained as JSONObject.

    public class main 
        public static void main(String[] args) throws MalformedURLException, IOException
            JSONObject data = getJSONfromURL("");
            JSONArray data_array = data.getJSONArray("values");

            for (int i = 0; i < data_array.length(); i++)
                JSONObject price_point = data_array.getJSONObject(i);

                //  Unix time
                int x = price_point.getInt("x");

                //  Bitcoin price at that time
                double y = price_point.getDouble("y");

                //  Do something with x and y.


        public static JSONObject getJSONfromURL(String URL)
                URLConnection uc;
                URL url = new URL(URL);
                uc = url.openConnection();
                uc.addRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)");

                BufferedReader rd = new BufferedReader(
                        new InputStreamReader(uc.getInputStream(), 

                StringBuilder sb = new StringBuilder();
                int cp;
                while ((cp = != -1)

                String jsonText = (sb.toString());            

                return new JSONObject(jsonText.toString());
            } catch (IOException ex)
                return null;

AngularJS open modal on button click

Hope this will help you .

Here is Html code:-

    <div ng-controller="MyController" class="container">
      <h1>Modal example</h1>
      <button ng-click="open()" class="btn btn-primary">Test Modal</button>

      <modal title="Login form" visible="showModal">
        <form role="form">


AngularJs code:-

var mymodal = angular.module('mymodal', []);

mymodal.controller('MyController', function ($scope) {
    $scope.showModal = false;
    $ = function(){
    $scope.showModal = !$scope.showModal;

mymodal.directive('modal', function () {
    return {
      template: '<div class="modal fade">' + 
          '<div class="modal-dialog">' + 
            '<div class="modal-content">' + 
              '<div class="modal-header">' + 
                '<button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>' + 
                '<h4 class="modal-title">{{ title }}</h4>' + 
              '</div>' + 
              '<div class="modal-body" ng-transclude></div>' + 
            '</div>' + 
          '</div>' + 
      restrict: 'E',
      transclude: true,
      link: function postLink(scope, element, attrs) {
        scope.title = attrs.title;

        scope.$watch(attrs.visible, function(value){
          if(value == true)

        $(element).on('', function(){
            scope.$parent[attrs.visible] = true;

        $(element).on('', function(){
            scope.$parent[attrs.visible] = false;

Check this--jsfiddle

JAVA Unsupported major.minor version 51.0

The Java runtime you try to execute your program with is an earlier version than Java 7 which was the target you compile your program for.

For Ubuntu use

apt-get install openjdk-7-jdk

to get Java 7 as default. You may have to uninstall openjdk-6 first.

How do we count rows using older versions of Hibernate (~2009)?

You could try count(*)

Integer count = (Integer) session.createQuery("select count(*) from Books").uniqueResult();

Where Books is the name off the class - not the table in the database.

How to update a record using sequelize for node?

I have used sequelize.js, node.js and transaction in below code and added proper error handling if it doesn't find data it will throw error that no data found with that id

editLocale: async (req, res) => {

    sequelize.sequelize.transaction(async (t1) => {

        if (! {
            return res.status(500).send(error.MANDATORY_FIELDS);

        let id =;

        let checkLocale= await sequelize.Locale.findOne({
            where: {
                id :

        checkLocale = checkLocale.get();
        if (checkLocale ) {
            let Locale= await sequelize.Locale.update(req.body, {
                where: {
                    id: id

            let result = error.OK;
   = Locale;

            return res.status(200).send(result);
        else {
            return res.status(404).send(error.DATA_NOT_FOUND);
    }).catch(function (err) {
        return res.status(500).send(error.SERVER_ERROR);

Python dictionary : TypeError: unhashable type: 'list'

As per your description, things don't add up. If aSourceDictionary is a dictionary, then your for loop has to work properly.

>>> source = {'a': [1, 2], 'b': [2, 3]}
>>> target = {}
>>> for key in source:
...   target[key] = []
...   target[key].extend(source[key])
>>> target
{'a': [1, 2], 'b': [2, 3]}

Determining the size of an Android view at runtime

Use below code, it is give the size of view.

public void onWindowFocusChanged(boolean hasFocus) {

How to set cookie value with AJAX request?

Basically, ajax request as well as synchronous request sends your document cookies automatically. So, you need to set your cookie to document, not to request. However, your request is cross-domain, and things became more complicated. Basing on this answer, additionally to set document cookie, you should allow its sending to cross-domain environment:

type: "GET",    
url: "",
cache: false,
// NO setCookies option available, set cookie to document
//setCookies: "lkfh89asdhjahska7al446dfg5kgfbfgdhfdbfgcvbcbc dfskljvdfhpl",
crossDomain: true,
dataType: 'json',
xhrFields: {
    withCredentials: true
success: function (data) {

Java - Change int to ascii

You can convert a number to ASCII in java. example converting a number 1 (base is 10) to ASCII.

char k = Character.forDigit(1, 10);
System.out.println("Character: " + k);
System.out.println("Character: " + ((int) k));


Character: 1
Character: 49

getting JRE system library unbound error in build path

I too faced the same issue. I followed the following steps to resolve my issue -

  • Right click on your project -> Properties
  • Select Java Build Path in the left menu
  • Select Libraries tab
  • Under the module path, select the troublesome JRE entry
  • Click on Edit button
  • Select Workspace default JRE.
  • Click on Finish button

If the above steps don't work for you, instead of Workspace default JRE, you can choose an Alternate JRE and give the path to the JRE that you want to point.

Need to remove href values when printing in Chrome

Bootstrap does the same thing (... as the selected answer below).

@media print {
  a[href]:after {
    content: " (" attr(href) ")";

Just remove it from there, or override it in your own print stylesheet:

@media print {
  a[href]:after {
    content: none !important;

IF - ELSE IF - ELSE Structure in Excel

When FIND returns #VALUE!, it is an error, not a string, so you can't compare FIND(...) with "#VALUE!", you need to check if FIND returns an error with ISERROR. Also FIND can work on multiple characters.

So a simplified and working version of your formula would be:

=IF(ISERROR(FIND("abc",A1))=FALSE, "Green", IF(ISERROR(FIND("xyz",A1))=FALSE, "Yellow", "Red"))

Or, to remove the double negations:

=IF(ISERROR(FIND("abc",A1)), IF(ISERROR(FIND("xyz",A1)), "Red", "Yellow"),"Green")

Floating point inaccuracy examples

There are basically two major pitfalls people stumble in with floating-point numbers.

  1. The problem of scale. Each FP number has an exponent which determines the overall “scale” of the number so you can represent either really small values or really larges ones, though the number of digits you can devote for that is limited. Adding two numbers of different scale will sometimes result in the smaller one being “eaten” since there is no way to fit it into the larger scale.

    PS> $a = 1; $b = 0.0000000000000000000000001
    PS> Write-Host a=$a b=$b
    a=1 b=1E-25
    PS> $a + $b

    As an analogy for this case you could picture a large swimming pool and a teaspoon of water. Both are of very different sizes, but individually you can easily grasp how much they roughly are. Pouring the teaspoon into the swimming pool, however, will leave you still with roughly a swimming pool full of water.

    (If the people learning this have trouble with exponential notation, one can also use the values 1 and 100000000000000000000 or so.)

  2. Then there is the problem of binary vs. decimal representation. A number like 0.1 can't be represented exactly with a limited amount of binary digits. Some languages mask this, though:

    PS> "{0:N50}" -f 0.1

    But you can “amplify” the representation error by repeatedly adding the numbers together:

    PS> $sum = 0; for ($i = 0; $i -lt 100; $i++) { $sum += 0.1 }; $sum

    I can't think of a nice analogy to properly explain this, though. It's basically the same problem why you can represent 1/3 only approximately in decimal because to get the exact value you need to repeat the 3 indefinitely at the end of the decimal fraction.

    Similarly, binary fractions are good for representing halves, quarters, eighths, etc. but things like a tenth will yield an infinitely repeating stream of binary digits.

  3. Then there is another problem, though most people don't stumble into that, unless they're doing huge amounts of numerical stuff. But then, those already know about the problem. Since many floating-point numbers are merely approximations of the exact value this means that for a given approximation f of a real number r there can be infinitely many more real numbers r1, r2, ... which map to exactly the same approximation. Those numbers lie in a certain interval. Let's say that rmin is the minimum possible value of r that results in f and rmax the maximum possible value of r for which this holds, then you got an interval [rmin, rmax] where any number in that interval can be your actual number r.

    Now, if you perform calculations on that number—adding, subtracting, multiplying, etc.—you lose precision. Every number is just an approximation, therefore you're actually performing calculations with intervals. The result is an interval too and the approximation error only ever gets larger, thereby widening the interval. You may get back a single number from that calculation. But that's merely one number from the interval of possible results, taking into account precision of your original operands and the precision loss due to the calculation.

    That sort of thing is called Interval arithmetic and at least for me it was part of our math course at the university.

bool to int conversion

Section of the C standard says:

Each of the operators < (less than), > (greater than), <= (less than or equal to), and >= (greater than or equal to) shall yield 1 if the specified relation is true and 0 if it is false.) The result has type int.

CURL and HTTPS, "Cannot resolve host"

If you do it on Windows XAMPP/WAMP it probaly won't work as in my case.

I solved the problem setting up Laravel's Homestead/Vagrant solution to create my (Ubuntu) development environment - it has built-in: Nginx, PHP 5.6, PHP 7.3, PHP 7.2, PHP 7.1, MySQL, PostgreSQL, Redis, Memcached, Node... to name just a few.

See here for info how to set up the environment - it's really worth the effort!

Laravel Homestead is an official, pre-packaged Vagrant box that provides you a wonderful development environment without requiring you to install PHP, a web server, and any other server software on your local machine. No more worrying about messing up your operating system! Vagrant boxes are completely disposable. If something goes wrong, you can destroy and re-create the box in minutes!

Then you can easily switch PHP versions or set up more virtual hosts, new databases just in seconds.

Merge two (or more) lists into one, in C# .NET

You can use the LINQ Concat and ToList methods:

var allProducts = productCollection1.Concat(productCollection2)

Note that there are more efficient ways to do this - the above will basically loop through all the entries, creating a dynamically sized buffer. As you can predict the size to start with, you don't need this dynamic sizing... so you could use:

var allProducts = new List<Product>(productCollection1.Count +
                                    productCollection2.Count +

(AddRange is special-cased for ICollection<T> for efficiency.)

I wouldn't take this approach unless you really have to though.

Creating a range of dates in Python

Here's a slightly different answer building off of S.Lott's answer that gives a list of dates between two dates start and end. In the example below, from the start of 2017 to today.

start = datetime.datetime(2017,1,1)
end =
daterange = [start + datetime.timedelta(days=x) for x in range(0, (end-start).days)]

DNS problem, nslookup works, ping doesn't

I had the same issue. As pointed out by other answers ping and nslookup use different mechanisms to lookup an ip.

Chances are you are trying to ping a machine not on the same domain. When you ping the fully qualified name of the server this should then work.

nslookup works:

PS C:\Users\Administrator> nslookup nuget


Ping fails:

PS C:\Users\Administrator> ping nuget
Ping request could not find host nuget. Please check the name and try again.

Ping works, using FQDN:

PS C:\Users\Administrator> ping

Pinging [] with 32 bytes of data:
Reply from bytes=32 time=1ms TTL=127
Reply from bytes=32 time=2ms TTL=127
Reply from bytes=32 time=2ms TTL=127
Reply from bytes=32 time=2ms TTL=127

Ping statistics for
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 1ms, Maximum = 2ms, Average = 1ms

To fix this you will need to alter the DNS setting for the machine and add the DNS suffix to lookup.

  1. Control Panel\Network and Internet\Network Connections
  2. Network adapter -> properties
  3. IPV4 -> Properties
  4. General tab -> Advanced
  5. DNS Tab
  6. Select "Append these DNS suffixes (in order)"
  7. Add the required domain names
  8. Disable, then enable your network adapter (don't do this on a VM, you'll loose your connection, instead try 'ipconfig /renew')

Advanced TCP/IP Settings

How do I concatenate two strings in C?

You should use strcat, or better, strncat. Google it (the keyword is "concatenating").

Get the current date in java.sql.Date format

These are all too long.

Just use:

new Date(System.currentTimeMillis())

Convert an object to an XML string

    public static string Serialize(object dataToSerialize)
        if(dataToSerialize==null) return null;

        using (StringWriter stringwriter = new System.IO.StringWriter())
            var serializer = new XmlSerializer(dataToSerialize.GetType());
            serializer.Serialize(stringwriter, dataToSerialize);
            return stringwriter.ToString();

    public static T Deserialize<T>(string xmlText)
        if(String.IsNullOrWhiteSpace(xmlText)) return default(T);

        using (StringReader stringReader = new System.IO.StringReader(xmlText))
            var serializer = new XmlSerializer(typeof(T));
            return (T)serializer.Deserialize(stringReader);

Call php function from JavaScript

This is, in essence, what AJAX is for. Your page loads, and you add an event to an element. When the user causes the event to be triggered, say by clicking something, your Javascript uses the XMLHttpRequest object to send a request to a server.

After the server responds (presumably with output), another Javascript function/event gives you a place to work with that output, including simply sticking it into the page like any other piece of HTML.

You can do it "by hand" with plain Javascript , or you can use jQuery. Depending on the size of your project and particular situation, it may be more simple to just use plain Javascript .

Plain Javascript

In this very basic example, we send a request to myAjax.php when the user clicks a link. The server will generate some content, in this case "hello world!". We will put into the HTML element with the id output.

The javascript

// handles the click event for link 1, sends the query
function getOutput() {
      'myAjax.php', // URL for the PHP file
       drawOutput,  // handle successful request
       drawError    // handle error
  return false;
// handles drawing an error message
function drawError() {
    var container = document.getElementById('output');
    container.innerHTML = 'Bummer: there was an error!';
// handles the response, adds the html
function drawOutput(responseText) {
    var container = document.getElementById('output');
    container.innerHTML = responseText;
// helper function for cross-browser request object
function getRequest(url, success, error) {
    var req = false;
        // most browsers
        req = new XMLHttpRequest();
    } catch (e){
        // IE
            req = new ActiveXObject("Msxml2.XMLHTTP");
        } catch(e) {
            // try an older version
                req = new ActiveXObject("Microsoft.XMLHTTP");
            } catch(e) {
                return false;
    if (!req) return false;
    if (typeof success != 'function') success = function () {};
    if (typeof error!= 'function') error = function () {};
    req.onreadystatechange = function(){
        if(req.readyState == 4) {
            return req.status === 200 ? 
                success(req.responseText) : error(req.status);
    }"GET", url, true);
    return req;


<a href="#" onclick="return getOutput();"> test </a>
<div id="output">waiting for action</div>


// file myAjax.php
  echo 'hello world!';

Try it out:

With a javascript library (jQuery et al)

Arguably, that is a lot of Javascript code. You can shorten that up by tightening the blocks or using more terse logic operators, of course, but there's still a lot going on there. If you plan on doing a lot of this type of thing on your project, you might be better off with a javascript library.

Using the same HTML and PHP from above, this is your entire script (with jQuery included on the page). I've tightened up the code a little to be more consistent with jQuery's general style, but you get the idea:

// handles the click event, sends the query
function getOutput() {
      complete: function (response) {
      error: function () {
          $('#output').html('Bummer: there was an error!');
  return false;

Try it out:

Don't rush out for jQuery just yet: adding any library is still adding hundreds or thousands of lines of code to your project just as surely as if you had written them. Inside the jQuery library file, you'll find similar code to that in the first example, plus a whole lot more. That may be a good thing, it may not. Plan, and consider your project's current size and future possibility for expansion and the target environment or platform.

If this is all you need to do, write the plain javascript once and you're done.


How to pick a new color for each plotted line within a figure in matplotlib?

matplotlib 1.5+

You can use axes.set_prop_cycle (example).

matplotlib 1.0-1.4

You can use axes.set_color_cycle (example).

matplotlib 0.x

You can use Axes.set_default_color_cycle.

How to center a <p> element inside a <div> container?

Centered and middled content ?

Do it this way :

<table style="width:100%">
        <td valign="middle" align="center">Table once ruled centering</td>

I fiddled it here

Ha, let me guess .. you want DIVs ..

just make your first outter DIV behave like a table-cell then style it with vertical align:middle;

    <p>I want this paragraph to be at the center, but I can't.</p>

div {
    /*  there it is */

Where is the Global.asax.cs file?

That's because you created a Web Site instead of a Web Application. The cs/vb files can only be seen in a Web Application, but in a website you can't have a separate cs/vb file.

Edit: In the website you can add a cs file behavior like..

<%@ Application CodeFile="Global.asax.cs" Inherits="ApplicationName.MyApplication" Language="C#" %>


namespace ApplicationName
    public partial class MyApplication : System.Web.HttpApplication
        protected void Application_Start()

What happened to Lodash _.pluck?

Ah-ha! The Lodash Changelog says it all...

"Removed _.pluck in favor of with iteratee shorthand"

var objects = [{ 'a': 1 }, { 'a': 2 }];

// in 3.10.1
_.pluck(objects, 'a'); // ? [1, 2], 'a'); // ? [1, 2]

// in 4.0.0, 'a'); // ? [1, 2]


VARCHAR means that it's a variable-length character, so it's only going to take as much space as is necessary. But if you knew something about the underlying structure, it may make sense to restrict VARCHAR to some maximum amount.

For instance, if you were storing comments from the user, you may limit the comment field to only 4000 characters; if so, it doesn't really make any sense to make the sql table have a field that's larger than VARCHAR(4000).

vertical & horizontal lines in matplotlib

This may be a common problem for new users of Matplotlib to draw vertical and horizontal lines. In order to understand this problem, you should be aware that different coordinate systems exist in Matplotlib.

The method axhline and axvline are used to draw lines at the axes coordinate. In this coordinate system, coordinate for the bottom left point is (0,0), while the coordinate for the top right point is (1,1), regardless of the data range of your plot. Both the parameter xmin and xmax are in the range [0,1].

On the other hand, method hlines and vlines are used to draw lines at the data coordinate. The range for xmin and xmax are the in the range of data limit of x axis.

Let's take a concrete example,

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 5, 100)
y = np.sin(x)

fig, ax = plt.subplots()

ax.plot(x, y)
ax.axhline(y=0.5, xmin=0.0, xmax=1.0, color='r')
ax.hlines(y=0.6, xmin=0.0, xmax=1.0, color='b')

It will produce the following plot: enter image description here

The value for xmin and xmax are the same for the axhline and hlines method. But the length of produced line is different.

Android Studio : How to uninstall APK (or execute adb command) automatically before Run or Debug?

List the packages by:

adb shell su 0 pm list packages

Review which package you want to uninstall and copy the package name from there. For example:

Lastly type in:

adb uninstall 

and you are done.

how to permit an array with strong parameters

If you have a hash structure like this:

Parameters: {"link"=>{"title"=>"Something", "time_span"=>[{"start"=>"2017-05-06T16:00:00.000Z", "end"=>"2017-05-06T17:00:00.000Z"}]}}

Then this is how I got it to work:

params.require(:link).permit(:title, time_span: [[:start, :end]])

Bootstrap dropdown not working

I had a similar issue only to observe that i had added the bootstrap script twice and the second bootstrap script was after above the jquery script.


  • Ensure that bootstrap.min.js and jquery.min.js are only included once in your file.
  • The bootstrap.min.js script should be included after jquery.min.js

How to hash some string with sha256 in Java?

If you are using Java 8 you can encode the byte[] by doing

MessageDigest digest = MessageDigest.getInstance("SHA-256");
byte[] hash = digest.digest(text.getBytes(StandardCharsets.UTF_8));
String encoded = Base64.getEncoder().encodeToString(hash);

How to make canvas responsive

this seems to be working :

  border: solid 1px blue; 

Get querystring from URL using jQuery


This is what you need :)

The following code will return a JavaScript Object containing the URL parameters:

// Read a page's GET URL variables and return them as an associative array.
function getUrlVars()
    var vars = [], hash;
    var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
    for(var i = 0; i < hashes.length; i++)
        hash = hashes[i].split('=');
        vars[hash[0]] = hash[1];
    return vars;

For example, if you have the URL:

This code will return:

    "me"    : "myValue",
    "name2" : "SomeOtherValue"

and you can do:

var me = getUrlVars()["me"];
var name2 = getUrlVars()["name2"];

Maven- No plugin found for prefix 'spring-boot' in the current project and in the plugin groups

In my case, my maven variable environment was M2_HOME, so I've changed to MAVEN_HOME and worked.

Deleting an SVN branch

Assuming this branch isn't an external or a symlink, removing the branch should be as simple as:

svn rm branches/< mybranch >

svn ci -m "message"

If you'd like to do this in the repository then update to remove it from your working copy you can do something like:

svn rm http://< myurl >/< myrepo >/branches/< mybranch >

Then run:

svn update

How to handle static content in Spring MVC?

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""

and if you want to use annotation based configuration use below code

    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {

Python argparse command line flags without arguments

Adding a quick snippet to have it ready to execute:


import argparse
parser = argparse.ArgumentParser(description="Flip a switch by setting a flag")
parser.add_argument('-w', action='store_true')

args = parser.parse_args()
print args.w


python -w
>> True

scrollTop animation without jquery


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

1# JavaScript (linear):

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

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

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

2# JavaScript (ease in and out):

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

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

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

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


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

enter image description here

3# Simple scrolling library on Github

Counting array elements in Perl

@people = qw( bob john linda ); 
$n = @people; # the number 3
Print " le number in the list is $n \n"; 

Expressions in Perl always return the appropriate value for their context. For example, how about the “name” * of an array. In a list context, it gives the list of elements. But in a scalar context, it returns the number of elements in the array:

how to destroy an object in java?

In java there is no explicit way doing garbage collection. The JVM itself runs some threads in the background checking for the objects that are not having any references which means all the ways through which we access the object are lost. On the other hand an object is also eligible for garbage collection if it runs out of scope that is the program in which we created the object is terminated or ended. Coming to your question the method finalize is same as the destructor in C++. The finalize method is actually called just before the moment of clearing the object memory by the JVM. It is up to you to define the finalize method or not in your program. However if the garbage collection of the object is done after the program is terminated then the JVM will not invoke the finalize method which you defined in your program. You might ask what is the use of finalize method? For instance let us consider that you created an object which requires some stream to external file and you explicitly defined a finalize method to this object which checks wether the stream opened to the file or not and if not it closes the stream. Suppose, after writing several lines of code you lost the reference to the object. Then it is eligible for garbage collection. When the JVM is about to free the space of your object the JVM just checks have you defined the finalize method or not and invokes the method so there is no risk of the opened stream. finalize method make the program risk free and more robust.

Why is Java Vector (and Stack) class considered obsolete or deprecated?

Vector was part of 1.0 -- the original implementation had two drawbacks:

1. Naming: vectors are really just lists which can be accessed as arrays, so it should have been called ArrayList (which is the Java 1.2 Collections replacement for Vector).

2. Concurrency: All of the get(), set() methods are synchronized, so you can't have fine grained control over synchronization.

There is not much difference between ArrayList and Vector, but you should use ArrayList.

From the API doc.

As of the Java 2 platform v1.2, this class was retrofitted to implement the List interface, making it a member of the Java Collections Framework. Unlike the new collection implementations, Vector is synchronized.

What is the advantage of using REST instead of non-REST HTTP?

I recommend taking a look at Ryan Tomayko's How I Explained REST to My Wife

Third party edit

Excerpt from the waybackmaschine link:

How about an example. You’re a teacher and want to manage students:

  • what classes they’re in,
  • what grades they’re getting,
  • emergency contacts,
  • information about the books you teach out of, etc.

If the systems are web-based, then there’s probably a URL for each of the nouns involved here: student, teacher, class, book, room, etc. ... If there were a machine readable representation for each URL, then it would be trivial to latch new tools onto the system because all of that information would be consumable in a standard way. ... you could build a country-wide system that was able to talk to each of the individual school systems to collect testing scores.

Each of the systems would get information from each other using a simple HTTP GET. If one system needs to add something to another system, it would use an HTTP POST. If a system wants to update something in another system, it uses an HTTP PUT. The only thing left to figure out is what the data should look like.

Passing arguments to require (when loading module)

Yes. In your login module, just export a single function that takes the db as its argument. For example:

module.exports = function(db) {

Can I make a phone call from HTML on Android?

Yes you can; it works on Android too:

tel: phone_number
Calls the entered phone number. Valid telephone numbers as defined in the IETF RFC 3966 are accepted. Valid examples include the following:

* tel:2125551212
* tel: (212) 555 1212

The Android browser uses the Phone app to handle the “tel” scheme, as defined by RFC 3966.
Clicking a link like:

<a href="tel:2125551212">2125551212</a>

on Android will bring up the Phone app and pre-enter the digits for 2125551212 without autodialing.

Have a look to RFC3966

How to convert FormData (HTML5 object) to JSON

Even though the answer from @dzuc is already very good, you could use array destructuring (available in modern browsers or with Babel) to make it even a bit more elegant:

// original version from @dzuc
const data = Array.from(formData.entries())
  .reduce((memo, pair) => ({
    [pair[0]: pair[1],
  }), {})

// with array destructuring
const data = Array.from(formData.entries())
  .reduce((memo,[key, value]) => ({
    [key]: value,
  }), {})

How can I run Tensorboard on a remote server?

You don't need to do anything fancy. Just run:

tensorboard --host <other args here>

and connect with your server url and port. The --host tells tensorflow to listen from connections on all IPv4 addresses on the local machine.

PHP, pass array through POST

Edit If you are asking about security, see my addendum at the bottom Edit

PHP has a serialize function provided for this specific purpose. Pass it an array, and it will give you a string representation of it. When you want to convert it back to an array, you just use the unserialize function.

$data = array('one'=>1, 'two'=>2, 'three'=>33);
$dataString = serialize($data);
//send elsewhere
$data = unserialize($dataString);

This is often used by lazy coders to save data to a database. Not recommended, but works as a quick/dirty solution.


I was under the impression that you were looking for a way to send the data reliably, not "securely". No matter how you pass the data, if it is going through the users system, you cannot trust it at all. Generally, you should store it somewhere on the server & use a credential (cookie, session, password, etc) to look it up.

Javascript: set label text

InnerHTML should be innerHTML:

document.getElementById('LblAboutMeCount').innerHTML = charsleft;

You should bind your checkLength function to your textarea with jQuery rather than calling it inline and rather intrusively:

$(document).ready(function() {
    $('textarea[name=text]').keypress(function(e) {
    }).focus(function() {

You can neaten up checkLength by using more jQuery, and I wouldn't use 'object' as a formal parameter:

function checkLength(obj, maxlength, label) {
    charsleft = (maxlength - obj.val().length);
    // never allow to exceed the specified limit
    if( charsleft < 0 ) {
        obj.val(obj.val().substring(0, maxlength-1));
    // I'm trying to set the value of charsleft into the label

So if you apply the above, you can change your markup to:

<textarea name="text"></textarea>

Laravel: PDOException: could not find driver

In CentOS7,I try this: yum install php-mysql, then edit php.ini

Windows batch - concatenate multiple text files into one

Place all files need to copied in a separate folder, for ease place them in c drive.

Open Command Prompt - windows>type cmd>select command prompt.

You can see the default directory pointing - Ex : C:[Folder_Name]>. Change the directory to point to the folder which you have placed files to be copied, using ' cd [Folder_Name] ' command.

After pointing to directory - type 'dir' which shows all the files present in folder, just to make sure everything at place.

Now type : 'copy *.txt [newfile_name].txt' and press enter.


All the text in individual files will be copied to [newfile_name].txt

Find unique rows in numpy.array

We can actually turn m x n numeric numpy array into m x 1 numpy string array, please try using the following function, it provides count, inverse_idx and etc, just like numpy.unique:

import numpy as np

def uniqueRow(a):
    #This function turn m x n numpy array into m x 1 numpy array storing 
    #string, and so the np.unique can be used

    #Input: an m x n numpy array (a)
    #Output unique m' x n numpy array (unique), inverse_indx, and counts 

    s = np.chararray((a.shape[0],1))
    s[:] = '-'

    b = (a).astype(np.str)

    s2 = np.expand_dims(b[:,0],axis=1) + s + np.expand_dims(b[:,1],axis=1)

    n = a.shape[1] - 2    

    for i in range(0,n):
         s2 = s2 + s + np.expand_dims(b[:,i+2],axis=1)

    s3, idx, inv_, c = np.unique(s2,return_index = True,  return_inverse = True, return_counts = True)

    return a[idx], inv_, c


A = np.array([[ 3.17   9.502  3.291],
  [ 9.984  2.773  6.852],
  [ 1.172  8.885  4.258],
  [ 9.73   7.518  3.227],
  [ 8.113  9.563  9.117],
  [ 9.984  2.773  6.852],
  [ 9.73   7.518  3.227]])

B, inv_, c = uniqueRow(A)


[[ 1.172  8.885  4.258]
[ 3.17   9.502  3.291]
[ 8.113  9.563  9.117]
[ 9.73   7.518  3.227]
[ 9.984  2.773  6.852]]

[3 4 1 0 2 4 0]

[2 1 1 1 2]

How can prevent a PowerShell window from closing so I can see the error?

The simplest and easiest way is to execute your particular script with -NoExit param.

1.Open run box by pressing:

Win + R

2.Then type into input prompt:

PowerShell -NoExit "C:\folder\script.ps1"

and execute.

How can I maintain fragment state when added to the back stack?

I came across this problem in a Fragment containing a map, which has too many setup details to save/reload. My solution was to basically keep this Fragment active the whole time (similar to what @kaushal mentioned).

Say you have current Fragment A and wants to display Fragment B. Summarizing the consequences:

  • replace() - remove Fragment A and replace it with Fragment B. Fragment A will be recreated once brought to the front again
  • add() - (create and) add a Fragment B and it overlap Fragment A, which is still active in the background
  • remove() - can be used to remove Fragment B and return to A. Fragment B will be recreated when called later on

Hence, if you want to keep both Fragments "saved", just toggle them using hide()/show().

Pros: easy and simple method to keep multiple Fragments running
Cons: you use a lot more memory to keep all of them running. May run into problems, e.g. displaying many large bitmaps

How to edit an Android app?

You would need to decompile the apk as Davis suggested, can use tools such as apkTool , then if you need to change the source code you would need other tools to do that.

You would then need to put the apk back together and sign it, if you don't have the original key used to sign the apk this means the new apk will have a different signature.

If the developer employed any obfuscation or other techniques to protect the app then it gets more complicated.

In short its a pretty complex and technical procedure, so if the developer is really just out of reach, its better to wait until he is in reach. And ask for the source code next time.

How to specify a port to run a create-react-app based project?

How about giving the port number while invoking the command without need to change anything in your application code or environment files? That way it is possible running and serving same code base from several different ports.


$ export PORT=4000 && npm start

You can put the port number you like in place of the example value 4000 above.

How to concatenate text from multiple rows into a single text string in SQL server?

--SQL Server 2005+

CREATE TABLE dbo.Students
    StudentId INT
    , Name VARCHAR(50)
    , CONSTRAINT PK_Students PRIMARY KEY (StudentId)

CREATE TABLE dbo.Subjects
    SubjectId INT
    , Name VARCHAR(50)
    , CONSTRAINT PK_Subjects PRIMARY KEY (SubjectId)

CREATE TABLE dbo.Schedules
    StudentId INT
    , SubjectId INT
    , CONSTRAINT PK__Schedule PRIMARY KEY (StudentId, SubjectId)
    , CONSTRAINT FK_Schedule_Students FOREIGN KEY (StudentId) REFERENCES dbo.Students (StudentId)
    , CONSTRAINT FK_Schedule_Subjects FOREIGN KEY (SubjectId) REFERENCES dbo.Subjects (SubjectId)

INSERT dbo.Students (StudentId, Name) VALUES
    (1, 'Mary')
    , (2, 'John')
    , (3, 'Sam')
    , (4, 'Alaina')
    , (5, 'Edward')

INSERT dbo.Subjects (SubjectId, Name) VALUES
    (1, 'Physics')
    , (2, 'Geography')
    , (3, 'French')
    , (4, 'Gymnastics')

INSERT dbo.Schedules (StudentId, SubjectId) VALUES
    (1, 1)      --Mary, Physics
    , (2, 1)    --John, Physics
    , (3, 1)    --Sam, Physics
    , (4, 2)    --Alaina, Geography
    , (5, 2)    --Edward, Geography

    , sub.Name AS [SubjectName]
    , ISNULL( x.Students, '') AS Students
    dbo.Subjects sub
            CASE ROW_NUMBER() OVER (ORDER BY stu.Name) WHEN 1 THEN '' ELSE ', ' END
            + stu.Name
            dbo.Students stu
            INNER JOIN dbo.Schedules sch
                ON stu.StudentId = sch.StudentId
            sch.SubjectId = sub.SubjectId
        ORDER BY
        FOR XML PATH('')
    ) x (Students)

node.js require all files in a folder?

Another option is to use the package require-dir which let's you do the following. It supports recursion as well.

var requireDir = require('require-dir');
var dir = requireDir('./path/to/dir');

How to calculate a mod b in Python?

A = [3, 1, 2, 4]
for a in A:
    print(a % 2)



How do I set the request timeout for one controller action in an mvc application

I had to add "Current" using .NET 4.5:

HttpContext.Current.Server.ScriptTimeout = 300;

Oracle SQL Where clause to find date records older than 30 days


 WHERE creation_date <= TRUNC(SYSDATE) - 30

SYSDATE returns the date & time; TRUNC resets the date to being as of midnight so you can omit it if you want the creation_date that is 30 days previous including the current time.

Depending on your needs, you could also look at using ADD_MONTHS:

 WHERE creation_date <= ADD_MONTHS(TRUNC(SYSDATE), -1)

ng-options with simple array init

You actually had it correct in your third attempt.

 <select ng-model="myselect" ng-options="o as o for o in options"></select>

See a working example here:

The trick is that AngularJS writes the keys as numbers from 0 to n anyway, and translates back when updating the model.

As a result, the HTML will look incorrect but the model will still be set properly when choosing a value. (i.e. AngularJS will translate '0' back to 'var1')

The solution by Epokk also works, however if you're loading data asynchronously you might find it doesn't always update correctly. Using ngOptions will correctly refresh when the scope changes.

Proper way to set response status and JSON content in a REST API made with nodejs and express

I don't see anyone mentioned the fact that the order of method calls on res object is important. I'm new to nodejs and didn't realize at first that res.json() does more than just setting the body of the response. It actually tries to infer the response status as well. So, if done like so:

res.json({"message": "Bad parameters"})

The second line would be of no use, because based on the correctly built json express/nodejs will already infer the success status(200).

How to register multiple implementations of the same interface in Asp.Net Core?

since my post above, I have moved to a Generic Factory Class


 services.AddFactory<IProcessor, string>()

 public MyClass(IFactory<IProcessor, string> processorFactory)
       var x = "A"; //some runtime variable to select which object to create
       var processor = processorFactory.Create(x);


public class FactoryBuilder<I, P> where I : class
    private readonly IServiceCollection _services;
    private readonly FactoryTypes<I, P> _factoryTypes;
    public FactoryBuilder(IServiceCollection services)
        _services = services;
        _factoryTypes = new FactoryTypes<I, P>();
    public FactoryBuilder<I, P> Add<T>(P p)
        where T : class, I
        _factoryTypes.ServiceList.Add(p, typeof(T));

        return this;
public class FactoryTypes<I, P> where I : class
    public Dictionary<P, Type> ServiceList { get; set; } = new Dictionary<P, Type>();

public interface IFactory<I, P>
    I Create(P p);

public class Factory<I, P> : IFactory<I, P> where I : class
    private readonly IServiceProvider _serviceProvider;
    private readonly FactoryTypes<I, P> _factoryTypes;
    public Factory(IServiceProvider serviceProvider, FactoryTypes<I, P> factoryTypes)
        _serviceProvider = serviceProvider;
        _factoryTypes = factoryTypes;

    public I Create(P p)
        return (I)_serviceProvider.GetService(_factoryTypes.ServiceList[p]);


namespace Microsoft.Extensions.DependencyInjection
    public static class DependencyExtensions
        public static FactoryBuilder<I, P> AddFactory<I, P>(this IServiceCollection services)
            where I : class
            services.AddTransient<IFactory<I, P>, Factory<I, P>>();
            return new FactoryBuilder<I, P>(services);

What are some good SSH Servers for windows?

I've been using Bitvise SSH Server for a number of years. It is a wonderful product and it is easy to setup and maintain. It gives you great control over how users connect to the server with support for security groups.

Do I need <class> elements in persistence.xml?

For those running JPA in Spring, from version 3.1 onwards, you can set packagesToScan property under LocalContainerEntityManagerFactoryBean and get rid of persistence.xml altogether.

Here's the low-down

How to select an item in a ListView programmatically?

        int i=99;//is what row you want to select and focus
        listViewRamos.FocusedItem = listViewRamos.Items[0];
        listViewRamos.Items[i].Selected = true;
        listViewRamos.EnsureVisible(i);//This is the trick

Convert HTML + CSS to PDF

Well if you want to find a perfect XHTML+CSS to PDF converter library, forget it. It's far from possible. Because it's just like finding a perfect browser (XHTML+CSS rendering engine). Do we have one? IE or FF?

I have had some success with DOMPDF. The thing is that you have to modify your HTML+CSS code to go with the way the library is meant to work. Other than that, I have pretty good results.

See below:

Original HTML

Converting HTML to PDF

How can I make IntelliJ IDEA update my dependencies from Maven?

For some reason IntelliJ (at least in version 2019.1.2) ignores dependencies in local .m2 directory. None of above solutions worked for me. The only thing finally forced IntelliJ to discover local dependencies was:

  1. Close project
  2. Open project clicking on pom.xml (not on a project directory)
  3. Click Open as Project

List item

  1. Click Delete Existing Project and Import

enter image description here

Remove all stylings (border, glow) from textarea

The glow effect is most-likely controlled by box-shadow. In addition to adding what Pavel said, you can add the box-shadow property for the different browser engines.

textarea {
    border: none;
    overflow: auto;
    outline: none;

    -webkit-box-shadow: none;
    -moz-box-shadow: none;
    box-shadow: none;

    resize: none; /*remove the resize handle on the bottom right*/

You may also try adding !important to prioritize this CSS.

Extracting the last n characters from a string in R

Use stri_sub function from stringi package. To get substring from the end, use negative numbers. Look below for the examples:

[1] "abc"
[1] "a"
[1] "cde"

You can install this package from github:

It is available on CRAN now, simply type


to install this package.

Convert JsonNode into POJO

String jsonInput = "{ \"hi\": \"Assume this is the JSON\"} ";
com.fasterxml.jackson.databind.ObjectMapper mapper =
    new com.fasterxml.jackson.databind.ObjectMapper();
MyClass myObject = objectMapper.readValue(jsonInput, MyClass.class);

If your JSON input in has more properties than your POJO has and you just want to ignore the extras in Jackson 2.4, you can configure your ObjectMapper as follows. This syntax is different from older Jackson versions. (If you use the wrong syntax, it will silently do nothing.)


How to convert a ruby hash object to JSON?

You should include json in your file

For Example,

require 'json'

your_hash = {one: "1", two: "2"}

For more knowledge about json you can visit below link. Json Learning

if...else within JSP or JSTL

You can write if-else condition inside <% %> in jsp pages and html code outside of <% %>

For example:

        String username = (String)session.getAttribute("username");
        if(username==null)  {
        <p> username is null</p> //html code
        } else {
        <p> username is not null</p> //html code

Convert AM/PM time to 24 hours format?

int hour = your hour value;
int min = your minute value;
String ampm = your am/pm value;

hour = ampm == "AM" ? hour : (hour % 12) + 12; //convert 12-hour time to 24-hour

var dateTime = new DateTime(0,0,0, hour, min, 0);
var timeString = dateTime.ToString("HH:mm");

How to compare Boolean?

Using direct conditions (like ==, !=, !condition) will have a slight performance improvement over the .equals(condition) as in one case you are calling the method from an object whereas direct comparisons are performed directly.

How to center horizontal table-cell

Short snippet for future visitors - how to center horizontal table-cell (+ vertically)

html, body {_x000D_
  width: 100%;_x000D_
  height: 100%;_x000D_
.tab {_x000D_
  display: table;_x000D_
  width: 100%;_x000D_
  height: 100%;_x000D_
.cell {_x000D_
  display: table-cell;_x000D_
  vertical-align: middle;_x000D_
  text-align: center; /* the key */_x000D_
  background-color: #EEEEEE;_x000D_
.content {_x000D_
  display: inline-block; /* important !! */_x000D_
  width: 100px;_x000D_
  background-color: #00FF00;_x000D_
<div class="tab">_x000D_
  <div class="cell">_x000D_
    <div class="content" id="a">_x000D_

Best practice to run Linux service as a different user

On Debian we use the start-stop-daemon utility, which handles pid-files, changing the user, putting the daemon into background and much more.

I'm not familiar with RedHat, but the daemon utility that you are already using (which is defined in /etc/init.d/functions, btw.) is mentioned everywhere as the equivalent to start-stop-daemon, so either it can also change the uid of your program, or the way you do it is already the correct one.

If you look around the net, there are several ready-made wrappers that you can use. Some may even be already packaged in RedHat. Have a look at daemonize, for example.

What does 'x packages are looking for funding' mean when running `npm install`?

npm fund [<pkg>]

This command retrieves information on how to fund the dependencies of a given project. If no package name is provided, it will list all dependencies that are looking for funding in a tree-structure in which are listed the type of funding and the url to visit.
The message can be disabled using: npm install --no-fund

Increase heap size in Java

On a 32-bit JVM, the largest heap size you can theoretically set is 4gb. To use a larger heap size, you need to use a 64-bit JVM. Try the following:

java -Xmx6144M -d64

The -d64 flag is important as this tells the JVM to run in 64-bit mode.

Trees in Twitter Bootstrap

Another great Treeview jquery plugin is

For an advance view you should check jquery-treetable

Numpy: Divide each row by a vector element

Pythonic way to do this is ...


This takes care of reshaping and also the results are in floating point format. In other answers results are in rounded integer format.

#NOTE: No of columns in both data and vector should match

How to configure Chrome's Java plugin so it uses an existing JDK in the machine

Apparently, Chrome addresses a key in Windows registry when it looks for a Java Environment. Since the plugin installs the JRE, this key is set to a JRE path and therefore needs to be edited if you want Chrome to work with the JDK.

  1. Run the plugin installer anyways.
  2. Start -> Run (Winkey+R) and then type in regedit to edit the registry.
  3. Find HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\MozillaPlugins\
  4. Export it as a reg file to say, your desktop (right-click and select Export).
  5. Uninstall the JRE (Control Panel -> Add or Remove Programs). This should delete the key above, explaining the need to export it in the first place.
  6. Open the reg file exported to your desktop with a text editor (such as Notepad++).
  7. Edit "Path" so that it matches the corresponding dll inside your JDK installation:

    "Description"="Oracle® Next Generation Java™ Plug-In"
    "Path"="C:\Program Files (x86)\Java\jdk1.6.0_29\jre\bin\new_plugin\npjp2.dll"
    "ProductName"="Oracle® Java™ Plug-In"
    "Vendor"="Oracle Corp."
  8. Save file.

  9. Double click modified reg file to add keys to your registry.

The REGEDIT 4 prefix at the top of the file might only be required for Windows 7 64-bit.

std::string to char*

(This answer applies to C++98 only.)

Please, don't use a raw char*.

std::string str = "string";
std::vector<char> chars(str.c_str(), str.c_str() + str.size() + 1u);
// use &chars[0] as a char*

How do I get the IP address into a batch-file variable?

This is a modification of @mousio's answer. My network connection is not persistent hence the IP address of the next adapter gets displayed if the string "IPv4 Address" is missing from ipconfig. The result of ipconfig has 2 blank spaces between adapters. After an adapter is found and 2 blank lines occurs before the "IPv4 Address" text, it assumes it is missing. Tested on Windows 7 64-bit only.

Processing blank lines from @dbenham's answer in: DOS batch FOR loop with FIND.exe is stripping out blank lines?

@echo off

rem --- complete adapter name to find without the ending ":" ---
set adapter=Wireless LAN adapter Wireless Network Connection

rem --- token under an adapter to extract IP address from ---
set IPAddrToken=IPv4 Address

setlocal enableextensions enabledelayedexpansion
set adapterfound=false
set emptylines=0
set ipaddress=

for /f "usebackq tokens=1-3 delims=:" %%e in (`ipconfig ^| findstr /n "^"`) do (

    set "item=%%f"

    if /i "!item!"=="!adapter!" (
        set adapterfound=true
        set emptylines=0
    ) else if not "!item!"=="" if not "!item!"=="!item:%IPAddrToken%=!" if "!adapterfound!"=="true" (
        @rem "!item:%IPAddrToken%=!" --> item with "IPv4 Address" removed
        set ipaddress=%%g
        goto :result
    if "%%f-%%g-!adapterfound!-!emptylines!"=="--true-1" (
        @rem 2nd blank line after adapter found
        goto :result
    if "%%f-%%g-!adapterfound!-!emptylines!"=="--true-0" (
        @rem 1st blank line after adapter found
        set emptylines=1


    echo %adapter%
    if not "%ipaddress%"=="" (
        echo    %IPAddrToken% =%ipaddress%
    ) else (
        if "%adapterfound%"=="true" (
            echo    %IPAddrToken% Not Found
        ) else (
            echo    Adapter Not Found


Close virtual keyboard on button press

For Activity,

InputMethodManager imm = (InputMethodManager)getSystemService(INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);

For Fragments, use getActivity()



InputMethodManager imm = (InputMethodManager)getActivity().getSystemService(INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(getActivity().getCurrentFocus().getWindowToken(), 0);

Non-numeric Argument to Binary Operator Error in R

Because your question is phrased regarding your error message and not whatever your function is trying to accomplish, I will address the error.

- is the 'binary operator' your error is referencing, and either CurrentDay or MA (or both) are non-numeric.

A binary operation is a calculation that takes two values (operands) and produces another value (see wikipedia for more). + is one such operator: "1 + 1" takes two operands (1 and 1) and produces another value (2). Note that the produced value isn't necessarily different from the operands (e.g., 1 + 0 = 1).

R only knows how to apply + (and other binary operators, such as -) to numeric arguments:

> 1 + 1
[1] 2
> 1 + 'one'
Error in 1 + "one" : non-numeric argument to binary operator

When you see that error message, it means that you are (or the function you're calling is) trying to perform a binary operation with something that isn't a number.


Your error lies in the use of [ instead of [[. Because Day is a list, subsetting with [ will return a list, not a numeric vector. [[, however, returns an object of the class of the item contained in the list:

> Day <- Transaction(1, 2)["b"]
> class(Day)
[1] "list"
> Day + 1
Error in Day + 1 : non-numeric argument to binary operator

> Day2 <- Transaction(1, 2)[["b"]]
> class(Day2)
[1] "numeric"
> Day2 + 1
[1] 3

Transaction, as you've defined it, returns a list of two vectors. Above, Day is a list contain one vector. Day2, however, is simply a vector.

Why use #define instead of a variable

Most common use (other than to declare constants) is an include guard.

How to convert JSON data into a Python object


With Python3, you can do it in one line, using SimpleNamespace and object_hook:

import json
from types import SimpleNamespace

data = '{"name": "John Smith", "hometown": {"name": "New York", "id": 123}}'

# Parse JSON into an object with attributes corresponding to dict keys.
x = json.loads(data, object_hook=lambda d: SimpleNamespace(**d))

OLD ANSWER (Python2)

In Python2, you can do it in one line, using namedtuple and object_hook (but it's very slow with many nested objects):

import json
from collections import namedtuple

data = '{"name": "John Smith", "hometown": {"name": "New York", "id": 123}}'

# Parse JSON into an object with attributes corresponding to dict keys.
x = json.loads(data, object_hook=lambda d: namedtuple('X', d.keys())(*d.values()))

or, to reuse this easily:

def _json_object_hook(d): return namedtuple('X', d.keys())(*d.values())
def json2obj(data): return json.loads(data, object_hook=_json_object_hook)

x = json2obj(data)

If you want it to handle keys that aren't good attribute names, check out namedtuple's rename parameter.

How to check if a string starts with "_" in PHP?

function starts_with($s, $prefix){
    // returns a bool
    return strpos($s, $prefix) === 0;

starts_with($variable, "_");

Most efficient way to append arrays in C#?

You might not need to concatenate end result into contiguous array. Instead, keep appending to the list as suggested by Jon. In the end you'll have a jagged array (well, almost rectangular in fact). When you need to access an element by index, use following indexing scheme:

double x = list[i / sampleSize][i % sampleSize];

Iteration over jagged array is also straightforward:

for (int iRow = 0; iRow < list.Length; ++iRow) {
  double[] row = list[iRow];
  for (int iCol = 0; iCol < row.Length; ++iCol) {
    double x = row[iCol];

This saves you memory allocation and copying at expense of slightly slower element access. Whether this will be a net performance gain depends on size of your data, data access patterns and memory constraints.

Uploading Laravel Project onto Web Server

Had this problem too and found out that the easiest way is to point your domain to the public folder and leave everything else the way they are.



Try the following statement:

select  distinct A.[Tag],
     count(A.[Tag]) as TAG_COUNT,
     (SELECT count(*) FROM [TagTbl] AS B WHERE A.[Tag]=B.[Tag] AND B.[ID]>0)
     from [TagTbl] AS A GROUP BY A.[Tag]

The first field will be the tag the second will be the whole count the third will be the positive ones count.

Regex for string not ending with given suffix

The accepted answer is fine if you can use lookarounds. However, there is also another approach to solve this problem.

If we look at the widely proposed regex for this question:


We will find that it almost works. It does not accept an empty string, which might be a little inconvinient. However, this is a minor issue when dealing with just a one character. However, if we want to exclude whole string, e.g. "abc", then:


won't do. It won't accept ac, for example.

There is an easy solution for this problem though. We can simply say:


or more generalized version:

.{,n-1}$|.*[^firstchar][^secondchar]$ where n is length of the string you want forbid (for abc it's 3), and firstchar, secondchar, ... are first, second ... nth characters of your string (for abc it would be a, then b, then c).

This comes from a simple observation that a string that is shorter than the text we won't forbid can not contain this text by definition. So we can either accept anything that is shorter("ab" isn't "abc"), or anything long enough for us to accept but without the ending.

Here's an example of find that will delete all files that are not .jpg:

find . -regex '.{,3}$|.*[^.][^j][^p][^g]$' -delete

How to show a confirm message before delete?

function del_confirm(msg,url)


<a  onclick="del_confirm('Are you Sure want to delete this record?','<filename>.php?action=delete&id=<?<id> >')"href="#"></a>

How to get a Char from an ASCII Character Code in c#

You can simply write:

char c = (char) 2;


char c = Convert.ToChar(2);

or more complex option for ASCII encoding only

char[] characters = System.Text.Encoding.ASCII.GetChars(new byte[]{2});
char c = characters[0];

Can we have multiple <tbody> in same <table>?

According to this example it can be done: w3-struct-tables.

How to debug Angular JavaScript Code

var rootEle = document.querySelector("html");
var ele = angular.element(rootEle); 

scope() We can fetch the $scope from the element (or its parent) by using the scope() method on the element:

var scope = ele.scope();


var injector = ele.injector();

With this injector, we can then then instantiate any Angular object inside of our app, such as services, other controllers, or any other object

Django Cookies, how can I set them?

Using Django's session framework should cover most scenarios, but Django also now provide direct cookie manipulation methods on the request and response objects (so you don't need a helper function).

Setting a cookie:

def view(request):
  response = HttpResponse('blah')
  response.set_cookie('cookie_name', 'cookie_value')

Retrieving a cookie:

def view(request):
  value = request.COOKIES.get('cookie_name')
  if value is None:
    # Cookie is not set

  # OR

    value = request.COOKIES['cookie_name']
  except KeyError:
    # Cookie is not set

How to make an Android device vibrate? with different frequency?

Use this:

import android.os.Vibrator;
     Vibrator v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
     // Vibrate for 1000 milliseconds
     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
     //deprecated in API 26 


Don't forget to include permission in AndroidManifest.xml file:

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

How can I check if a view is visible or not in Android?

Or you could simply use


How to change a text with jQuery


Try this for a clean approach.

var $toptitle = $('#toptitle');

if ( $toptitle.text() == 'Profile' ) // No {} brackets necessary if it's just one line.  
  $toptitle.text('New Word');         

Maven Could not resolve dependencies, artifacts could not be resolved

As an alternative source to the same problem, this answer cites using Maven 3 versus Maven 2 as the potential cause of this issue. Near as I can tell, this is due to changes in local repository resolution that was changed in Maven 3. Putting this here in case anyone else googles for it and reaches this answer (as I did).

Browser detection in JavaScript?

I recommend using the tiny javascript library Bowser, yes no r. It is based on the navigator.userAgent and quite well tested for all browsers including iphone, android etc.

You can use simply say:

if (bowser.msie && bowser.version <= 6) {
  alert('Hello IE');
} else if (bowser.firefox){
  alert('Hello Foxy');
} else if ({
  alert('Hello Chrome');
} else if (bowser.safari){
  alert('Hello Safari');
} else if(bowser.iphone ||{
  alert('Hello mobile');

How to fix UITableView separator on iOS 7?

This is default by iOS7 design. try to do the below:

[tableView setSeparatorInset:UIEdgeInsetsMake(0, 0, 0, 0)];

You can set the 'Separator Inset' from the storyboard:

enter image description here

enter image description here

How to check if a socket is connected/disconnected in C#?

Just use the KeepAlive like @toster-cx says and then use the Socket Connected status to check if the Socket is still connected. Set your receive timeout at the same timeout of the keepalive. If you have more questions i am always happy to help!

How to use graphics.h in codeblocks?

  • Open the file graphics.h using either of Sublime Text Editor or Notepad++,from the include folder where you have installed Codeblocks.
  • Goto line no 302
  • Delete the line and paste int left=0, int top=0, int right=INT_MAX, int bottom=INT_MAX, in that line.
  • Save the file and start Coding.

Python to open Chrome browser

Please check this:

import webbrowser
chrome_path = 'C:/Program Files (x86)/Google/Chrome/Application/chrome.exe %s'

ipynb import another ipynb file


!pip install ipynb

and then import the other notebook as

from ipynb.fs.full.<notebook_name> import *


from ipynb.fs.full.<notebook_name> import <function_name>

Make sure that all the notebooks are in the same directory.

Edit 1: You can see the official documentation here -

Also, if you would like to import only class & function definitions from a notebook (and not the top level statements), you can use ipynb.fs.defs instead of ipynb.fs.full. Full uppercase variable assignment will get evaluated as well.

How to handle calendar TimeZones using Java?

You say that the date is used in connection with web services, so I assume that is serialized into a string at some point.

If this is the case, you should take a look at the setTimeZone method of the DateFormat class. This dictates which time zone that will be used when printing the time stamp.

A simple example:

SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");

Calendar cal = Calendar.getInstance();
String timestamp = formatter.format(cal.getTime());

Safely remove migration In Laravel

I will rather do it manually

  1. Delete the model first (if you don't) need the model any longer
  2. Delete the migration from ...database/migrations folder
  3. If you have already migrated i.e if you have already run php artisan migrate, log into your phpmyadmin or SQL(whichever the case is) and in your database, delete the table created by the migration
  4. Still within your database, in the migrations folder, locate the row with that migration file name and delete the row.

Works for me, hope it helps!

Error: Cannot invoke an expression whose type lacks a call signature

Add a type to your variable and then return.


const myVariable : string [] = ['hello', 'there'];

const result => {

=> Important part is adding the string[] type etc:

html text input onchange event

Well unless I misunderstand you can just use the onChange attribute:

<input type="text" onChange="return bar()">

Note: in FF 3 (at least) this is not called until some the user has confirmed they are changed either by clicking away from the element, clicking enter, or other.

How to call a stored procedure from Java and JPA

This answer might be helpful if you have entity manager

I had a stored procedure to create next number and on server side I have seam framework.

Client side

 Object on = entityManager.createNativeQuery("EXEC getNextNmber").executeUpdate();"New order id: " + on.toString());

Database Side (SQL server) I have stored procedure named getNextNmber

Laravel Eloquent: How to get only certain columns from joined tables

For Laravel >= 5.2

Use the ->pluck() method

$roles = DB::table('roles')->pluck('title');

If you would like to retrieve an array containing the values of a single column, you may use the pluck method

For Laravel <= 5.1

Use the ->lists() method

$roles = DB::table('roles')->lists('title');

This method will return an array of role titles. You may also specify a custom key column for the returned array:

How to capture Enter key press?

You need to create a handler for the onkeypress action.


<input name="keywords" type="text" id="keywords" size="50" onkeypress="handleEnter(this, event)" />


function handleEnter(inField, e)
    var charCode;

    //Get key code (support for all browsers)
    if(e && e.which)
        charCode = e.which;
    else if(window.event)
        e = window.event;
        charCode = e.keyCode;

    if(charCode == 13)
       //Call your submit function

What's the difference between window.location= and window.location.replace()?

window.location adds an item to your history in that you can (or should be able to) click "Back" and go back to the current page.

window.location.replace replaces the current history item so you can't go back to it.

See window.location:

assign(url): Load the document at the provided URL.

replace(url):Replace the current document with the one at the provided URL. The difference from the assign() method is that after using replace() the current page will not be saved in session history, meaning the user won't be able to use the Back button to navigate to it.

Oh and generally speaking:

window.location.href = url;

is favoured over:

window.location = url;

How can I do a case insensitive string comparison?

I think you will find more information in this link:

Use the Compare static method on the String class to compare the two strings. Whether the comparison is case-insensitive is determined by the third parameter of one of its overloads. For example:

string lowerCase = "abc";
string upperCase = "AbC";
int caseInsensitiveResult = string.Compare(lowerCase, upperCase,
int caseSensitiveResult = string.Compare(lowerCase,

The caseSensitiveResult value is -1 (indicating that lowerCase is "less than" upperCase) and the caseInsensitiveResult is zero (indicating that lowerCase "equals" upperCase).

Xcode/Simulator: How to run older iOS version?

To anyone else who finds this older question, you can now download all old versions.

Xcode -> Preferences -> Components (Click on Simulators tab).

Install all the versions you want/need.

To show all installed simulators:

Target -> In dropdown "deployment target" choose the installed version with lowest version nr.

You should now see all your available simulators in the dropdown.

Why is the Java main method static?

Any method declared as static in Java belongs to the class itself . Again static method of a particular class can be accessed only by referring to the class like Class_name.method_name();

So a class need not to be instantiated before accessing a static method.

So the main() method is declared as static so that it can be accessed without creating an object of that class.

Since we save the program with the name of the class where the main method is present( or from where the program should begin its execution, applicable for classes without a main() method()(Advanced Level)). So by the above mentioned way:


the main method can be accessed.

In brief when the program is compiled it searches for the main() method having String arguments like: main(String args[]) in the class mentioned(i.e. by the name of the program), and since at the the beginning it has no scope to instantiate that class, so the main() method is declared as static.

iPhone get SSID without private library

This works for me on the device (not simulator). Make sure you add the systemconfiguration framework.

#import <SystemConfiguration/CaptiveNetwork.h>

+ (NSString *)currentWifiSSID {
    // Does not work on the simulator.
    NSString *ssid = nil;
    NSArray *ifs = (__bridge_transfer id)CNCopySupportedInterfaces();
    for (NSString *ifnam in ifs) {
        NSDictionary *info = (__bridge_transfer id)CNCopyCurrentNetworkInfo((__bridge CFStringRef)ifnam);
        if (info[@"SSID"]) {
            ssid = info[@"SSID"];
    return ssid;

Truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all()

This excellent answer explains very well what is happening and provides a solution. I would like to add another solution that might be suitable in similar cases: using the query method:

result = result.query("(var > 0.25) or (var < -0.25)")

See also

(Some tests with a dataframe I'm currently working with suggest that this method is a bit slower than using the bitwise operators on series of booleans: 2 ms vs. 870 µs)

A piece of warning: At least one situation where this is not straightforward is when column names happen to be python expressions. I had columns named WT_38hph_IP_2, WT_38hph_input_2 and log2(WT_38hph_IP_2/WT_38hph_input_2) and wanted to perform the following query: "(log2(WT_38hph_IP_2/WT_38hph_input_2) > 1) and (WT_38hph_IP_2 > 20)"

I obtained the following exception cascade:

  • KeyError: 'log2'
  • UndefinedVariableError: name 'log2' is not defined
  • ValueError: "log2" is not a supported function

I guess this happened because the query parser was trying to make something from the first two columns instead of identifying the expression with the name of the third column.

A possible workaround is proposed here.

Ignoring new fields on JSON objects using Jackson

Jackson provides an annotation that can be used on class level (JsonIgnoreProperties).

Add the following to the top of your class (not to individual methods):

@JsonIgnoreProperties(ignoreUnknown = true)
public class Foo {

Depending on the jackson version you are using you would have to use a different import in the current version it is:

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

in older versions it has been:

import org.codehaus.jackson.annotate.JsonIgnoreProperties;

Reordering Chart Data Series

FYI, if you are using two y-axis, the order numbers will only make a difference within the set of series of that y-axis. I believe secondary -y-axis by default are on top of the primary. If you want the series in the primary axis to be on top, you'll need to make it secondary instead.

tomcat - CATALINA_BASE and CATALINA_HOME variables

CATALINA_BASE is optional.

However, in the following scenarios it helps to setup CATALINA_BASE that is separate from CATALINA_HOME.

  1. When more than 1 instances of tomcat are running on same host

    • This helps have only 1 runtime of tomcat installation, with multiple CATALINA_BASE server configurations running on separate ports.
    • If any patching, or version upgrade needs be, only 1 installation changes required, or need to be tested/verified/signed-off.
  2. Separation of concern (Single responsibility)

    • Tomcat runtime is standard and does not change during every release process. i.e. Tomcat binaries
    • Release process may add more stuff as webapplication (webapps folder), environment configuration (conf directory), logs/temp/work directory

Remove trailing newline from the elements of a string list

All other answers, and mainly about list comprehension, are great. But just to explain your error:

strip_list = []
for lengths in range(1,20):
    strip_list.append(0) #longest word in the text file is 20 characters long
for a in lines:

a is a member of your list, not an index. What you could write is this:

for a in lines:

Another important comment: you can create an empty list this way:

strip_list = [0] * 20

But this is not so useful, as .append appends stuff to your list. In your case, it's not useful to create a list with defaut values, as you'll build it item per item when appending stripped strings.

So your code should be like:

strip_list = []
for a in lines:

But, for sure, the best one is this one, as this is exactly the same thing:

stripped = [line.strip() for line in lines]

In case you have something more complicated than just a .strip, put this in a function, and do the same. That's the most readable way to work with lists.

How to generate random number in Bash?

You can also use shuf (available in coreutils).

shuf -i 1-100000 -n 1

Could not find main class HelloWorld

JAVA_HOME is not necessary if you start java and javac from the command line. But JAVA_HOME should point to the real jdk directory, C:\Program Files\Java\jdk1.7.0 in your case.

I'd never use the CLASSPATH environment variable outside of build scripts, especially not global defined. The -cp flag is better. But in your case, as you do not need additional libraries (rt.jardoesn't count), you won't need a classpath declaration. A missing -cp is equivalent to a -cp . and that's what you need here)

The HelloWorld class needs to be declared as public. This actually may be the cause for your problems. (I was pretty sure, that a source file needs one public class... or was it one public class at most ?)

Print page numbers on pages when printing html

   **@page {
            margin-top:21% !important; 
            content: element(header);


            @bottom-left {
            content: element(footer
 div.header {

            position: running(header);

            div.footer {

            position: running(footer);
            border-bottom: 2px solid black;

           .pagenumber:before {
            content: counter(page);
            .pagecount:before {
            content: counter(pages);
 <div class="footer" style="font-size:12pt; font-family: Arial; font-family: Arial;">
                <span>Page <span class="pagenumber"/> of <span class="pagecount"/></span>
            </div >**

Scala vs. Groovy vs. Clojure

Obviously, the syntax are completely different (Groovy is closest to Java), but I suppose that is not what you are asking for.

If you are interested in using them to script a Java application, Scala is probably not a good choice, as there is no easy way to evaluate it from Java, whereas Groovy is especially suited for that purpose.

How do I get a file's directory using the File object?

If you do something like this:

File file = new File("test.txt");
String parent = file.getParent();

parent will be null.

So to get directory of this file you can do next:

parent = file.getAbsoluteFile().getParent();

TypeError: only length-1 arrays can be converted to Python scalars while plot showing

Take note of what is printed for x. You are trying to convert an array (basically just a list) into an int. length-1 would be an array of a single number, which I assume numpy just treats as a float. You could do this, but it's not a purely-numpy solution.

EDIT: I was involved in a post a couple of weeks back where numpy was slower an operation than I had expected and I realised I had fallen into a default mindset that numpy was always the way to go for speed. Since my answer was not as clean as ayhan's, I thought I'd use this space to show that this is another such instance to illustrate that vectorize is around 10% slower than building a list in Python. I don't know enough about numpy to explain why this is the case but perhaps someone else does?

import numpy as np
import matplotlib.pyplot as plt
import datetime

time_start =

# My original answer
def f(x):
    rebuilt_to_plot = []
    for num in x:
    return rebuilt_to_plot

for t in range(10000):
    x = np.arange(1, 15.1, 0.1)
    plt.plot(x, f(x))

time_end =

# Answer by ayhan
def f_1(x):

for t in range(10000):
    f2 = np.vectorize(f_1)
    x = np.arange(1, 15.1, 0.1)
    plt.plot(x, f2(x))

time_end_2 =

print time_end - time_start
print time_end_2 - time_end

Get connection status on client

Track the state of the connection yourself. With a boolean. Set it to false at declaration. Use the various events (connect, disconnect, reconnect, etc.) to reassign the current boolean value. Note: Using undocumented API features (e.g., socket.connected), is not a good idea; the feature could get removed in a subsequent version without the removal being mentioned.

Defining private module functions in python

This is an ancient question, but both module private (one underscore) and class-private (two underscores) mangled variables are now covered in the standard documentation:

The Python Tutorial » Classes » Private Variables

Big O, how do you calculate/approximate it?

As to "how do you calculate" Big O, this is part of Computational complexity theory. For some (many) special cases you may be able to come with some simple heuristics (like multiplying loop counts for nested loops), esp. when all you want is any upper bound estimation, and you do not mind if it is too pessimistic - which I guess is probably what your question is about.

If you really want to answer your question for any algorithm the best you can do is to apply the theory. Besides of simplistic "worst case" analysis I have found Amortized analysis very useful in practice.

Get day of week using NSDate

I ended up needing a few more strings from the date, including date of the week (e.g. "5th") and month of the year (e.g. Aug). Below are all three functions I have created based upon @Martin R's function and modified to return 3 char strings:

//Date String Helper Functions
func getDayOfWeek(today:String)->String? {
    let formatter  = NSDateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    if let todayDate = formatter.dateFromString(today) {
        let myCalendar = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!
        let myComponents = myCalendar.components(.Weekday, fromDate: todayDate)
        let weekDay = myComponents.weekday
        switch weekDay {
        case 1:
            return "Sun"
        case 2:
            return "Mon"
        case 3:
            return "Tue"
        case 4:
            return "Wed"
        case 5:
            return "Thu"
        case 6:
            return "Fri"
        case 7:
            return "Sat"
            print("Error fetching days")
            return "Day"
    } else {
        return nil

func getDateOfMonth(today:String)->String? {
    let formatter  = NSDateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    if let todayDate = formatter.dateFromString(today) {
        let myCalendar = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!
        let myComponents = myCalendar.components(.Day, fromDate: todayDate)
        let weekDay =
        switch weekDay {
        case 1:
            return "1st"
        case 2:
            return "2nd"
        case 3:
            return "3rd"
        case 4:
            return "4th"
        case 5:
            return "5th"
        case 6:
            return "6th"
        case 7:
            return "7th"
        case 8:
            return "8th"
        case 9:
            return "9th"
        case 10:
            return "10th"
        case 11:
            return "11th"
        case 12:
            return "12th"
        case 13:
            return "13th"
        case 14:
            return "14th"
        case 15:
            return "15th"
        case 16:
            return "16th"
        case 17:
            return "17th"
        case 18:
            return "18th"
        case 19:
            return "19th"
        case 20:
            return "20th"
        case 21:
            return "21st"
        case 22:
            return "22nd"
        case 23:
            return "23rd"
        case 24:
            return "24th"
        case 25:
            return "25th"
        case 26:
            return "26th"
        case 27:
            return "27th"
        case 28:
            return "28th"
        case 29:
            return "29th"
        case 30:
            return "30th"
        case 31:
            return "31st"
            print("Error fetching Date Of Month")
            return "Day"
    } else {
        return nil

func getMonthOfYear(today:String)->String? {
    let formatter  = NSDateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    if let todayDate = formatter.dateFromString(today) {
        let myCalendar = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!
        let myComponents = myCalendar.components(.Month, fromDate: todayDate)
        let month = myComponents.month
        switch month {
        case 1:
            return "Jan"
        case 2:
            return "Feb"
        case 3:
            return "Mar"
        case 4:
            return "Apr"
        case 5:
            return "May"
        case 6:
            return "Jun"
        case 7:
            return "Jul"
        case 8:
            return "Aug"
        case 9:
            return "Sep"
        case 10:
            return "Oct"
        case 11:
            return "Nov"
        case 12:
            return "Dec"
            print("Error fetching months")
            return "Month"
    } else {
        return nil

Center a DIV horizontally and vertically

You want to set style

margin: auto;

And remove the positioning styles (top, left, position)

I know this will center horrizontaly but I'm not sure about vertical!

How to automatically generate unique id in SQL like UID12345678?

Table Creating

create table emp(eno int identity(100001,1),ename varchar(50))

Values inserting

insert into emp(ename)values('narendra'),('ajay'),('anil'),('raju')

Select Table

select * from emp


eno     ename
100001  narendra
100002  rama
100003  ajay
100004  anil
100005  raju

Python find min max and average of a list (array)

from __future__ import division

somelist =  [1,12,2,53,23,6,17] 
max_value = max(somelist)
min_value = min(somelist)
avg_value = 0 if len(somelist) == 0 else sum(somelist)/len(somelist)

If you want to manually find the minimum as a function:

somelist =  [1,12,2,53,23,6,17] 

def my_min_function(somelist):
    min_value = None
    for value in somelist:
        if not min_value:
            min_value = value
        elif value < min_value:
            min_value = value
    return min_value

Python 3.4 introduced the statistics package, which provides mean and additional stats:

from statistics import mean, median

somelist =  [1,12,2,53,23,6,17]
avg_value = mean(somelist)
median_value = median(somelist)

Python: URLError: <urlopen error [Errno 10060]

Answer (Basic is advance!):

Error: 10060 Adding a timeout parameter to request solved the issue for me.

Example 1

import urllib
import urllib2
g = ""
read = urllib2.urlopen(g, timeout=20)

Example 2

A similar error also occurred while I was making a GET request. Again, passing a timeout parameter solved the 10060 Error.

response = requests.get(param_url, timeout=20)

Changing the text on a label

Use the config method to change the value of the label:

top = Tk()

l = Label(top)

l.config(text = "Hello World", width = "50")