Programs & Examples On #Simpletest

Simpletest is a Unit and Web Testing framework developed in PHP. You can read more about it and how to set it up at

Eclipse JUnit - possible causes of seeing "initializationError" in Eclipse window

I had the same issue... I was using maven building tool with JUnit dependency scope as 'test' and my @Test method was in main module.

To resolve, I've: 1. Commented the scope tag of JUnit dependency in the pom.xml 2. Rebuilt the package 3. Made sure the Test class has only one constructor

The issue can be two-folded: 1. The JUnit dependency is limited to test scope and the @Test method is in main scope 2. The test class has more than one constructor

Why does visual studio 2012 not find my tests?

Quick check list for solving some common test problems. Make sure that:

  1. Test class and test methods are public
  2. Test class has [TestClass] attribute
  3. Test methods have [TestMethod] attribute

If this does not help, try cleaning, rebuilding solution and restarting Visual Studio.

urllib2 and json

This is what worked for me:

import json
import requests
url = ''
payload = {'param': '1', 'data': '2', 'field': '4'}
headers = {'content-type': 'application/json'}
r =, data = json.dumps(payload), headers = headers)

jQuery show for 5 seconds then hide

You can use the below effect to animate, you can change the values as per your requirements

$("#myElem").fadeIn('slow').animate({opacity: 1.0}, 1500).effect("pulsate", { times: 2 }, 800).fadeOut('slow'); 

Get the filePath from Filename using Java

You may use:

FileSystems.getDefault().getPath(new String()).toAbsolutePath();


FileSystems.getDefault().getPath(new String("./")).toAbsolutePath().getParent()

This will give you the root folder path without using the name of the file. You can then drill down to where you want to go.

Example: /src/main/java...

An invalid form control with name='' is not focusable

Alternatively another and foolproof answer is to use HTML5 Placeholder attribute then there will be no need to use any js validations.

<input id="elemID" name="elemName" placeholder="Some Placeholder Text" type="hidden" required="required">

Chrome will not be able to find any empty, hidden and required elements to focus on. Simple Solution.

Hope that helps. I am totally sorted with this solution.

c++ boost split string

The problem is somewhere else in your code, because this works:

string line("test\ttest2\ttest3");
vector<string> strs;

cout << "* size of the vector: " << strs.size() << endl;    
for (size_t i = 0; i < strs.size(); i++)
    cout << strs[i] << endl;

and testing your approach, which uses a vector iterator also works:

string line("test\ttest2\ttest3");
vector<string> strs;

cout << "* size of the vector: " << strs.size() << endl;
for (vector<string>::iterator it = strs.begin(); it != strs.end(); ++it)
    cout << *it << endl;

Again, your problem is somewhere else. Maybe what you think is a \t character on the string, isn't. I would fill the code with debugs, starting by monitoring the insertions on the vector to make sure everything is being inserted the way its supposed to be.


* size of the vector: 3


This xsl:stylesheet can use a specified list of column headers and will ensure that the rows will be ordered correctly.

<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="" xmlns:csv="csv:csv">
    <xsl:output method="text" encoding="utf-8" />
    <xsl:strip-space elements="*" />

    <xsl:variable name="delimiter" select="','" />


    <xsl:template match="/property-manager/properties">
        <!-- Output the CSV header -->
        <xsl:for-each select="document('')/*/csv:columns/*">
                <xsl:value-of select="."/>
                <xsl:if test="position() != last()">
                    <xsl:value-of select="$delimiter"/>

        <!-- Output rows for each matched property -->
        <xsl:apply-templates select="property" />

    <xsl:template match="property">
        <xsl:variable name="property" select="." />

        <!-- Loop through the columns in order -->
        <xsl:for-each select="document('')/*/csv:columns/*">
            <!-- Extract the column name and value -->
            <xsl:variable name="column" select="." />
            <xsl:variable name="value" select="$property/*[name() = $column]" />

            <!-- Quote the value if required -->
                <xsl:when test="contains($value, '&quot;')">
                    <xsl:variable name="x" select="replace($value, '&quot;',  '&quot;&quot;')"/>
                    <xsl:value-of select="concat('&quot;', $x, '&quot;')"/>
                <xsl:when test="contains($value, $delimiter)">
                    <xsl:value-of select="concat('&quot;', $value, '&quot;')"/>
                    <xsl:value-of select="$value"/>

            <!-- Add the delimiter unless we are the last expression -->
            <xsl:if test="position() != last()">
                <xsl:value-of select="$delimiter"/>

        <!-- Add a newline at the end of the record -->


How to change the status bar background color and text color on iOS 7?

1) set the UIViewControllerBasedStatusBarAppearance to YES in the plist

2) in viewDidLoad do a [self setNeedsStatusBarAppearanceUpdate];

3) add the following method:

    return UIStatusBarStyleLightContent; 

also check developers-guide-to-the-ios-7-status-bar

Floating Div Over An Image

Never fails, once I post the question to SO, I get some enlightening "aha" moment and figure it out. The solution:

    .container {_x000D_
       border: 1px solid #DDDDDD;_x000D_
       width: 200px;_x000D_
       height: 200px;_x000D_
       position: relative;_x000D_
    .tag {_x000D_
       float: left;_x000D_
       position: absolute;_x000D_
       left: 0px;_x000D_
       top: 0px;_x000D_
       z-index: 1000;_x000D_
       background-color: #92AD40;_x000D_
       padding: 5px;_x000D_
       color: #FFFFFF;_x000D_
       font-weight: bold;_x000D_
<div class="container">_x000D_
       <div class="tag">Featured</div>_x000D_
       <img src="">_x000D_

The key is the container has to be positioned relative and the tag positioned absolute.

How to fix the session_register() deprecated issue?

if you need a fallback function you could use this

function session_register($name){
    global $$name;
    $_SESSION[$name] = $$name;
    $$name = &$_SESSION[$name]; 

Java Swing - how to show a panel on top of another panel?

I think LayeredPane is your best bet here. You would need a third panel though to contain A and B. This third panel would be the layeredPane and then panel A and B could still have a nice LayoutManagers. All you would have to do is center B over A and there is quite a lot of examples in the Swing trail on how to do this. Tutorial for positioning without a LayoutManager.

public class Main {
    private JFrame frame = new JFrame();
    private JLayeredPane lpane = new JLayeredPane();
    private JPanel panelBlue = new JPanel();
    private JPanel panelGreen = new JPanel();
    public Main()
        frame.setPreferredSize(new Dimension(600, 400));
        frame.setLayout(new BorderLayout());
        frame.add(lpane, BorderLayout.CENTER);
        lpane.setBounds(0, 0, 600, 400);
        panelBlue.setBounds(0, 0, 600, 400);
        panelGreen.setBounds(200, 100, 100, 100);
        lpane.add(panelBlue, new Integer(0), 0);
        lpane.add(panelGreen, new Integer(1), 0);

     * @param args the command line arguments
    public static void main(String[] args) {
        new Main();


You use setBounds to position the panels inside the layered pane and also to set their sizes.

Edit to reflect changes to original post You will need to add component listeners that detect when the parent container is being resized and then dynamically change the bounds of panel A and B.

How to work with string fields in a C struct?

This does not work:

string s = (string)malloc(sizeof string); 

string refers to a pointer, you need the size of the structure itself:

string s = malloc(sizeof (*string)); 

Note the lack of cast as well (conversion from void* (malloc's return type) is implicitly performed).

Also, in your main, you have a globally delcared patient, but that is uninitialized. Try:

 patient.number = 3; = "John";     
 patient.address = "Baker street";     
 patient.birthdate = "4/15/2012";     
 patient.gender = 'M';     

before you read-access any of its members

Also, strcpy is inherently unsafe as it does not have boundary checking (will copy until the first '\0' is encountered, writing past allocated memory if the source is too long). Use strncpy instead, where you can at least specify the maximum number of characters copied -- read the documentation to ensure you pass the correct value, it is easy to make an off-by-one error.

Violation of PRIMARY KEY constraint. Cannot insert duplicate key in object

I was getting the same error on a restored database when I tried to insert a new record using the EntityFramework. It turned out that the Indentity/Seed was screwing things up.

Using a reseed command fixed it.

DBCC CHECKIDENT ('[Prices]', RESEED, 4747030);GO

Prevent Caching in ASP.NET MVC for specific actions using an attribute

To ensure that JQuery isn't caching the results, on your ajax methods, put the following:

    cache: false
    //rest of your ajax setup

Or to prevent caching in MVC, we created our own attribute, you could do the same. Here's our code:

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public sealed class NoCacheAttribute : ActionFilterAttribute
    public override void OnResultExecuting(ResultExecutingContext filterContext)


Then just decorate your controller with [NoCache]. OR to do it for all you could just put the attribute on the class of the base class that you inherit your controllers from (if you have one) like we have here:

public class ControllerBase : Controller, IControllerBase

You can also decorate some of the actions with this attribute if you need them to be non-cacheable, instead of decorating the whole controller.

If your class or action didn't have NoCache when it was rendered in your browser and you want to check it's working, remember that after compiling the changes you need to do a "hard refresh" (Ctrl+F5) in your browser. Until you do so, your browser will keep the old cached version, and won't refresh it with a "normal refresh" (F5).

Composer killed while updating

I've got this error when I ran composer install inside my PHP DOCKER container, It's a memory issue. Solved by increasing SWAP memory in DOCKER PREFERENCES from 512MB to 1.5GB

To do that:

Docker -> Preferences -> Rousources

enter image description here

What is time_t ultimately a typedef to?

[root]# cat time.c

#include <time.h>

int main(int argc, char** argv)
        time_t test;
        return 0;

[root]# gcc -E time.c | grep __time_t

typedef long int __time_t;

It's defined in $INCDIR/bits/types.h through:

# 131 "/usr/include/bits/types.h" 3 4
# 1 "/usr/include/bits/typesizes.h" 1 3 4
# 132 "/usr/include/bits/types.h" 2 3 4

Android - Spacing between CheckBox and text

only you need to have one parameter in xml file


Producer/Consumer threads using a Queue

  1. Java code "BlockingQueue" which has synchronized put and get method.
  2. Java code "Producer" , producer thread to produce data.
  3. Java code "Consumer" , consumer thread to consume the data produced.
  4. Java code "ProducerConsumer_Main", main function to start the producer and consumer thread.

public class BlockingQueue 
    int item;
    boolean available = false;

    public synchronized void put(int value) 
        while (available == true)
            } catch (InterruptedException e) { 

        item = value;
        available = true;

    public synchronized int get()
        while(available == false)
            catch(InterruptedException e){

        available = false;
        return item;

package com.sukanya.producer_Consumer;

public class Consumer extends Thread
    blockingQueue queue;
    private int number;
    Consumer(BlockingQueue queue,int number)
        this.queue = queue;
        this.number = number;

    public void run()
        int value = 0;

        for (int i = 0; i < 10; i++) 
            value = queue.get();
            System.out.println("Consumer #" + this.number+ " got: " + value);

package com.sukanya.producer_Consumer;

public class ProducerConsumer_Main 
    public static void main(String args[])
        BlockingQueue queue = new BlockingQueue();
        Producer producer1 = new Producer(queue,1);
        Consumer consumer1 = new Consumer(queue,1);

Unable to install packages in latest version of RStudio and R Version.3.1.1

I think this is the "set it and forget it" solution:


Note that this isn't https. I was on a Linux machine, ssh'ing in. If I used https, it didn't work.

How to consume a webApi from Web API to store result in database?

public class EmployeeApiController : ApiController
    private readonly IEmployee _employeeRepositary;

    public EmployeeApiController()
        _employeeRepositary = new EmployeeRepositary();

    public async Task<HttpResponseMessage> Create(EmployeeModel Employee)
        var returnStatus = await _employeeRepositary.Create(Employee);
        return Request.CreateResponse(HttpStatusCode.OK, returnStatus);


public async Task<ResponseStatusViewModel> Create(EmployeeModel Employee)
    var responseStatusViewModel = new ResponseStatusViewModel();
    var connection = new SqlConnection(EmployeeConfig.EmployeeConnectionString);
                var command = new SqlCommand("usp_CreateEmployee", connection);
                command.CommandType = CommandType.StoredProcedure;
                var pEmployeeName = new SqlParameter("@EmployeeName", SqlDbType.VarChar, 50);
                pEmployeeName.Value = Employee.EmployeeName;

                    await connection.OpenAsync();
                    await command.ExecuteNonQueryAsync();


                catch (Exception ex)

                    throw ex;
                return responseStatusViewModel;


Task<ResponseStatusViewModel> Create(EmployeeModel Employee);

public class EmployeeConfig
    public static string EmployeeConnectionString;
    private const string EmployeeConnectionStringKey = "EmployeeConnectionString";
    public static void InitializeConfig()
        EmployeeConnectionString = GetConnectionStringValue(EmployeeConnectionStringKey);

    private static string GetConnectionStringValue(string connectionStringName)
        return Convert.ToString(ConfigurationManager.ConnectionStrings[connectionStringName]);

Sql Query to list all views in an SQL Server 2005 database

Run this adding DatabaseName in where condition.

  WHERE TABLE_CATALOG = 'DatabaseName'

or remove where condition adding use.

  use DataBaseName


How to install PyQt5 on Windows?

If you're using Windows 10, if you use

    py -m pip install pyqt5

in the command prompt it should download fine. Depending on either the version of Python or Windows sometimes python -m pip install pyqt5 isn't accepted, so you have to use py instead. pip is a good way to download a lot of stuff, so I'd recommend that.

What is the easiest way to clear a database from the CLI with in Django?

Quickest (drops and creates all tables including data):

./ reset appname | ./ dbshell


  • Might not work on Windows correctly.
  • Might keep some old tables in the db

ThreeJS: Remove object from scene

I had The same problem like you have. I try this code and it works just fine: When you create your object put this object.is_ob = true

function loadOBJFile(objFile){            
    /* material of OBJ model */                                          
    var OBJMaterial = new THREE.MeshPhongMaterial({color: 0x8888ff});
    var loader = new THREE.OBJLoader();
    loader.load(objFile, function (object){
        object.traverse (function (child){
            if (child instanceof THREE.Mesh) {
                child.material = OBJMaterial;
        object.position.y = 0.1;
      // add this code
        object.is_ob = true;


function addEntity(object) {

And then then you delete your object try this code:

function removeEntity(object){
    var obj, i;
            for ( i = scene.children.length - 1; i >= 0 ; i -- ) {
                obj = scene.children[ i ];
                if ( obj.is_ob) {


Try that and tell me if that works, it seems that three js doesn't recognize the object after added to the scene. But with this trick it works.

How to format an inline code in Confluence?

The easiest way I've found to do this is to write in markdown right from the start of the line. Press Ctrl+D (shortcut for opening the markup input dialog) and type markdown. The normal wiki editor doesn't seem to be very good for precise formatting. It doesn't seem to know much about character styles and only knows paragraph styles.

Switch: Multiple values in one case?

What about this?

switch (true) 
    case (age >= 1 && age <= 8):
        MessageBox.Show("You are only " + age + " years old\n You must be kidding right.\nPlease fill in your *real* age.");
    case (age >= 9 && age <= 15):
        MessageBox.Show("You are only " + age + " years old\n That's too young!");
    case (age >= 16 && age <= 100):
        MessageBox.Show("You are " + age + " years old\n Perfect.");
        MessageBox.Show("You an old person.");



The function STR_TO_DATE(COLUMN, '%input_format') can do it, you only have to specify the input format. Example : to convert p052011

SELECT STR_TO_DATE('p052011','p%m%Y') FROM your_table;

The result : 2011-05-00

Windows batch: sleep

timeout /t 10 /nobreak > NUL

/t specifies the time to wait in seconds

/nobreak won't interrupt the timeout if you press a key (except CTRL-C)

> NUL will suppress the output of the command

How do I make this executable via double click?

By default, *.sh files are opened in a text editor (Xcode or TextEdit). To create a shell script that will execute in Terminal when you open it, name it with the “command” extension, e.g., file.command. By default, these are sent to Terminal, which will execute the file as a shell script.

You will also need to ensure the file is executable, e.g.:

chmod +x file.command

Without this, Terminal will refuse to execute it.

Note that the script does not have to begin with a #! prefix in this specific scenario, because Terminal specifically arranges to execute it with your default shell. (Of course, you can add a #! line if you want to customize which shell is used or if you want to ensure that you can execute it from the command line while using a different shell.)

Also note that Terminal executes the shell script without changing the working directory. You’ll need to begin your script with a cd command if you actually need it to run with a particular working directory.

How to get function parameter names/values dynamically?

Ok so an old question with plenty of adequate answers. here is my offering that does not use regex, except for the menial task of stripping whitespace . (I should note that the "strips_comments" function actually spaces them out, rather than physically remove them. that's because i use it elsewhere and for various reasons need the locations of the original non comment tokens to stay intact)

It's a fairly lengthy block of code as this pasting includes a mini test framework.

    function do_tests(func) {

    if (typeof func !== 'function') return true;
    switch (typeof func.tests) {
        case 'undefined' : return true;
        case 'object'    : 
            for (var k in func.tests) {

                var test = func.tests[k];
                if (typeof test==='function') {
                    var result = test(func);
                    if (result===false) {
                        return false;

            return true;
        case 'function'  : 
            return func.tests(func);
    return true;
function strip_comments(src) {

    var spaces=(s)=>{
        switch (s) {
            case 0 : return '';
            case 1 : return ' ';
            case 2 : return '  ';
        default : 
            return Array(s+1).join(' ');

    var c1 = src.indexOf ('/*'),
        c2 = src.indexOf ('//'),

    var out = "";

    var killc2 = () => {
                out += src.substr(0,c2);
                eol =  src.indexOf('\n',c2);
                if (eol>=0) {
                    src = spaces(eol-c2)+'\n'+src.substr(eol+1);
                } else {
                    src = spaces(src.length-c2);
                    return true;

             return false;

    while ((c1>=0) || (c2>=0)) {
         if (c1>=0) {
             // c1 is a hit
             if ( (c1<c2) || (c2<0) )  {
                 // and it beats c2
                 out += src.substr(0,c1);
                 eol = src.indexOf('*/',c1+2);
                 if (eol>=0) {
                      src = spaces((eol-c1)+2)+src.substr(eol+2);
                 } else {
                      src = spaces(src.length-c1);
             } else {

                 if (c2 >=0) {
                     // c2 is a hit and it beats c1
                     if (killc2()) break;
         } else {
             if (c2>=0) {
                // c2 is a hit, c1 is a miss.
                if (killc2()) break;  
             } else {
                 // both c1 & c2 are a miss

         c1 = src.indexOf ('/*');
         c2 = src.indexOf ('//');   

    return out + src;

function function_args(fn) {
    var src = strip_comments(fn.toString());
    var names=src.split(')')[0].replace(/\s/g,'').split('(')[1].split(',');
    return names;

function_args.tests = [

     function test1 () {

            function/*al programmers will sometimes*/strip_comments_tester/* because some comments are annoying*/(
            /*see this---(((*/ src//)) it's an annoying comment does not help anyone understand if the 
            ,code,//really does
            /**/sucks ,much /*?*/)/*who would put "comment\" about a function like (this) { comment } here?*/{


        var data = function_args(strip_comments_tester);

        return ( (data.length==4) &&
                 (data[0]=='src') &&
                 (data[1]=='code') &&
                 (data[2]=='sucks') &&
                 (data[3]=='much')  );



How to save LogCat contents to file?

Additional tip for the programmatic approach:

String filePath = Environment.getExternalStorageDirectory() + "/logcat.txt";
Runtime.getRuntime().exec(new String[]{"logcat", "-f", filepath, "MyAppTAG:V", "*:S"});

This opens a continuous output stream between logcat and the file provided. This can result in a deadlock if you then waitFor the Process returned by exec, or an exception if the provided file is prematurely disposed.

I found that including the "-d" flag simply dumps logcat and closes the connection, which prevents the above behavior.

Get the length of a String

Get string value from your textview or textfield:

let textlengthstring = (yourtextview?.text)! as String

Find the count of the characters in the string:

let numberOfChars = textlength.characters.count

Google Chrome default opening position and size

You should just grab the window by the title bar and snap it to the left side of your screen (close browser) then reopen the browser ans snap it to the top... problem is over.

Installing Pandas on Mac OSX

You can install python with homebrew:

brew install python

Make sure that OSX uses the correct path:

which python

Then you can use the pip tool to install pandas:

pip install pandas

Make sure that all dependencies are installed. I followed this tutorial:

Works fine on my machine.

Why are my PowerShell scripts not running?

On Windows 10: Click change security property of myfile.ps1 and change "allow access" by right click / properties on myfile.ps1

How to merge two files line by line in Bash

You can use paste:

paste file1.txt file2.txt > fileresults.txt

Mockito: Inject real objects into private @Autowired fields

I know this is an old question, but we were faced with the same problem when trying to inject Strings. So we invented a JUnit5/Mockito extension that does exactly what you want:


 private Map<String, Object> injectionMap = new HashMap<>();

 public void beforeEach() throws Exception {
  injectionMap.put("securityEnabled", Boolean.TRUE);

 public void afterEach() throws Exception {

C# - How to get Program Files (x86) on Windows 64 bit

The function below will return the x86 Program Files directory in all of these three Windows configurations:

  • 32 bit Windows
  • 32 bit program running on 64 bit Windows
  • 64 bit program running on 64 bit windows


static string ProgramFilesx86()
    if( 8 == IntPtr.Size 
        || (!String.IsNullOrEmpty(Environment.GetEnvironmentVariable("PROCESSOR_ARCHITEW6432"))))
        return Environment.GetEnvironmentVariable("ProgramFiles(x86)");

    return Environment.GetEnvironmentVariable("ProgramFiles");

Thymeleaf: how to use conditionals to dynamically add/remove a CSS class

Another very similar answer is to use "equals" instead of "contains".

<li th:class="${#strings.equals(pageTitle,'How It Works')} ? active : ''">

Convert List into Comma-Separated String

We can try like this to separate list enties by comma

string stations = 
haul.Routes != null && haul.Routes.Count > 0 ?String.Join(",",haul.Routes.Select(y => 
y.RouteCode).ToList()) : string.Empty;

Move an array element from one array position to another

Another pure JS variant using ES6 array spread operator with no mutation

const reorder = (array, sourceIndex, destinationIndex) => {_x000D_
 const smallerIndex = Math.min(sourceIndex, destinationIndex);_x000D_
 const largerIndex = Math.max(sourceIndex, destinationIndex);_x000D_
 return [_x000D_
  ...array.slice(0, smallerIndex),_x000D_
  ...(sourceIndex < destinationIndex_x000D_
   ? array.slice(smallerIndex + 1, largerIndex + 1)_x000D_
   : []),_x000D_
  ...(sourceIndex > destinationIndex_x000D_
   ? array.slice(smallerIndex, largerIndex)_x000D_
   : []),_x000D_
  ...array.slice(largerIndex + 1),_x000D_
// returns ['a', 'c', 'd', 'e', 'b', 'f']_x000D_
console.log(reorder(['a', 'b', 'c', 'd', 'e', 'f'], 1, 4))_x000D_

Splitting words into letters in Java

"Stack Me 123 Heppa1 oeu".toCharArray() ?

JWT (JSON Web Token) library for Java

IETF has suggested jose libs on it's wiki:

I would highly recommend using them for signing. I am not a Java guy, but seems like jose4j seems like a good option. Has nice examples as well:

Update: provides a neat comparison of several jwt related libraries, and their features. A must check!

I would love to hear about what other java devs prefer.

Web scraping with Python

You can use urllib2 to make the HTTP requests, and then you'll have web content.

You can get it like this:

import urllib2
response = urllib2.urlopen('')
html =

Beautiful Soup is a python HTML parser that is supposed to be good for screen scraping.

In particular, here is their tutorial on parsing an HTML document.

Good luck!

Assert that a method was called in a Python unit test

You can mock out aw.Clear, either manually or using a testing framework like pymox. Manually, you'd do it using something like this:

class MyTest(TestCase):
  def testClear():
    old_clear = aw.Clear
    clear_calls = 0
    aw.Clear = lambda: clear_calls += 1
    aps.Request('nv2', aw)
    assert clear_calls == 1
    aw.Clear = old_clear

Using pymox, you'd do it like this:

class MyTest(mox.MoxTestBase):
  def testClear():
    aw = self.m.CreateMock(aps.Request)
    aps.Request('nv2', aw)

Best way to convert list to comma separated string in java

You could count the total length of the string first, and pass it to the StringBuilder constructor. And you do not need to convert the Set first.

Set<String> abc = new HashSet<String>();

String separator = ", ";
int total = abc.size() * separator.length();
for (String s : abc) {
    total += s.length();

StringBuilder sb = new StringBuilder(total);
for (String s : abc) {

String result = sb.substring(separator.length()); // remove leading separator

How to export html table to excel or pdf in php

Either you can use CSV functions or PHPExcel

or you can try like below

$test="<table  ><tr><td>Cell 1</td><td>Cell 2</td></tr></table>";
header("Content-type: application/");
header("Content-Disposition: attachment; filename=$file");
echo $test;

The header for .xlsx files is Content-type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

How to fix Subversion lock error

Error : Attempted to lock an already-locked dir svn: Working copy 'C:\work\myproject\workspaces\HPDP' locked.

Solution: Worked for me.

        Right-click on project-->Team-->Refresh/Cleanup

Remove all of x axis labels in ggplot

You have to set to element_blank() in theme() elements you need to remove

ggplot(data = diamonds, mapping = aes(x = clarity)) + geom_bar(aes(fill = cut))+

How to use RecyclerView inside NestedScrollView?

One solution to keep the recycling feature of the recyclerview and avoiding the recyclerview to load all your data is setting a fix height in the recyclerview itself. By doing this the recyclerview is limited only to load as much as its height can show the user thus recycling its element if ever you scroll to the bottom/top.

Java String to JSON conversion

Instead of JSONObject , you can use ObjectMapper to convert java object to json string

ObjectMapper mapper = new ObjectMapper();
String requestBean = mapper.writeValueAsString(yourObject);

Sum rows in data.frame or matrix

you can use rowSums

rowSums(data) should give you what you want.

'Property does not exist on type 'never'

if you're receiving the error in parameter, so keep any or any[] type of input like below

getOptionLabel={(option: any) => option!.name}
    getOptionLabel={(option: any) => option!.name}

Pandas: rolling mean by time interval

What about something like this:

First resample the data frame into 1D intervals. This takes the mean of the values for all duplicate days. Use the fill_method option to fill in missing date values. Next, pass the resampled frame into pd.rolling_mean with a window of 3 and min_periods=1 :

pd.rolling_mean(df.resample("1D", fill_method="ffill"), window=3, min_periods=1)

            favorable  unfavorable     other
2012-10-25   0.495000     0.485000  0.025000
2012-10-26   0.527500     0.442500  0.032500
2012-10-27   0.521667     0.451667  0.028333
2012-10-28   0.515833     0.450000  0.035833
2012-10-29   0.488333     0.476667  0.038333
2012-10-30   0.495000     0.470000  0.038333
2012-10-31   0.512500     0.460000  0.029167
2012-11-01   0.516667     0.456667  0.026667
2012-11-02   0.503333     0.463333  0.033333
2012-11-03   0.490000     0.463333  0.046667
2012-11-04   0.494000     0.456000  0.043333
2012-11-05   0.500667     0.452667  0.036667
2012-11-06   0.507333     0.456000  0.023333
2012-11-07   0.510000     0.443333  0.013333

UPDATE: As Ben points out in the comments, with pandas 0.18.0 the syntax has changed. With the new syntax this would be:

df.resample("1d").sum().fillna(0).rolling(window=3, min_periods=1).mean()

"npm config set registry" is not working in windows bat file

We can also run npm install with registry options for multiple custom registry URLs.

npm install --registry= 
npm install --registry= 

Angularjs: Get element in controller

You can pass in the element to the controller, just like the scope:

function someControllerFunc($scope, $element){


Python dictionary: Get list of values for list of keys

Try this:

mydict = {'one': 1, 'two': 2, 'three': 3}
mykeys = ['three', 'one'] # if there are many keys, use a set

[mydict[k] for k in mykeys]
=> [3, 1]

jQuery date formatting

You can add new user jQuery function 'getDate'

JSFiddle: getDate jQuery

Or you can run code snippet. Just press "Run code snippet" button below this post.

// Create user jQuery function 'getDate'_x000D_
(function( $ ){_x000D_
   $.fn.getDate = function(format) {_x000D_
 var gDate  = new Date();_x000D_
 var mDate  = {_x000D_
 'S': gDate.getSeconds(),_x000D_
 'M': gDate.getMinutes(),_x000D_
 'H': gDate.getHours(),_x000D_
 'd': gDate.getDate(),_x000D_
 'm': gDate.getMonth() + 1,_x000D_
 'y': gDate.getFullYear(),_x000D_
 // Apply format and add leading zeroes_x000D_
 return format.replace(/([SMHdmy])/g, function(key){return (mDate[key] < 10 ? '0' : '') + mDate[key];});_x000D_
 return getDate(str);_x000D_
   }; _x000D_
})( jQuery );_x000D_
// Usage: example #1. Write to '#date' div_x000D_
$('#date').html($().getDate("y-m-d H:M:S"));_x000D_
// Usage: ex2. Simple clock. Write to '#clock' div_x000D_
function clock(){_x000D_
 $('#clock').html($().getDate("H:M:S, m/d/y"))_x000D_
setInterval(clock, 1000); // One second_x000D_
// Usage: ex3. Simple clock 2. Write to '#clock2' div_x000D_
function clock2(){_x000D_
 var format = 'H:M:S'; // Date format_x000D_
 var updateInterval = 1000; // 1 second_x000D_
 var clock2Div = $('#clock2'); // Get div_x000D_
 var currentTime = $().getDate(format); // Get time_x000D_
 clock2Div.html(currentTime); // Write to div_x000D_
 setTimeout(clock2, updateInterval); // Set timer 1 second_x000D_
// Run clock2_x000D_
// Just for fun_x000D_
// Usage: ex4. Simple clock 3. Write to '#clock3' span_x000D_
function clock3(){_x000D_
 var formatHM = 'H:M:'; // Hours, minutes_x000D_
 var formatS = 'S'; // Seconds_x000D_
 var updateInterval = 1000; // 1 second_x000D_
 var clock3SpanHM = $('#clock3HM'); // Get span HM_x000D_
 var clock3SpanS = $('#clock3S'); // Get span S_x000D_
 var currentHM = $().getDate(formatHM); // Get time H:M_x000D_
 var currentS = $().getDate(formatS); // Get seconds_x000D_
 clock3SpanHM.html(currentHM); // Write to div_x000D_
 clock3SpanS.fadeOut(1000).html(currentS).fadeIn(1); // Write to span_x000D_
 setTimeout(clock3, updateInterval); // Set timer 1 second_x000D_
// Run clock2_x000D_
<script src=""></script>_x000D_
<div id="date"></div><br>_x000D_
<div id="clock"></div><br>_x000D_
<span id="clock3HM"></span><span id="clock3S"></span>


Named parameters in JDBC

To avoid including a large framework, I think a simple homemade class can do the trick.

Example of class to handle named parameters:

public class NamedParamStatement {
    public NamedParamStatement(Connection conn, String sql) throws SQLException {
        int pos;
        while((pos = sql.indexOf(":")) != -1) {
            int end = sql.substring(pos).indexOf(" ");
            if (end == -1)
                end = sql.length();
                end += pos;
            sql = sql.substring(0, pos) + "?" + sql.substring(end);
        prepStmt = conn.prepareStatement(sql);

    public PreparedStatement getPreparedStatement() {
        return prepStmt;
    public ResultSet executeQuery() throws SQLException {
        return prepStmt.executeQuery();
    public void close() throws SQLException {

    public void setInt(String name, int value) throws SQLException {        
        prepStmt.setInt(getIndex(name), value);

    private int getIndex(String name) {
        return fields.indexOf(name)+1;
    private PreparedStatement prepStmt;
    private List<String> fields = new ArrayList<String>();

Example of calling the class:

String sql;
sql = "SELECT id, Name, Age, TS FROM TestTable WHERE Age < :age OR id = :id";
NamedParamStatement stmt = new NamedParamStatement(conn, sql);
stmt.setInt("age", 35);
stmt.setInt("id", 2);
ResultSet rs = stmt.executeQuery();

Please note that the above simple example does not handle using named parameter twice. Nor does it handle using the : sign inside quotes.

Difference between Constructor and ngOnInit

I found the answer and I tried to translate it to english: This question still arised, even in technical interviews. In fact, there is a big resemblance between the two, but also there are some differences.

  • The constructor is part of ECMAScript. On the other hand ngOnInit() is a notion of angular.

  • We can call the constructors in all classes even if we do not use Angular

  • LifeCycle: The constructor is called before ngOnInt ()

  • In the constructor we can not call HTML elements. However, in ngOnInit () we can.

  • Generally, calls of services in the ngOnInit () and not in the constructor


How to validate Google reCAPTCHA v3 on server side?

I liked Levit's answer and ended up using it. But I just wanted to point out, just in case, that there is an official Google PHP library for new reCAPTCHA:

The latest version (right now 1.1.2) supports Composer and contains an example that you can run to see if you have configured everything correctly.

Below you can see part of the example that comes with this official library (with my minor modifications for clarity):

// Make the call to verify the response and also pass the user's IP address
    $resp = $recaptcha->verify($_POST['g-recaptcha-response'], $_SERVER['REMOTE_ADDR']);

    if ($resp->isSuccess()) {
// If the response is a success, that's it!
        <p>That's it. Everything is working. Go integrate this into your real project.</p>
        <p><a href="/">Try again</a></p>
    } else {
// If it's not successful, then one or more error codes will be returned.
        <h2>Something went wrong</h2>
        <p>The following error was returned: <?php
            foreach ($resp->getErrorCodes() as $code) {
                echo '<tt>' , $code , '</tt> ';
        <p>Check the error code reference at <tt><a href=""></a></tt>.
        <p><strong>Note:</strong> Error code <tt>missing-input-response</tt> may mean the user just didn't complete the reCAPTCHA.</p>
        <p><a href="/">Try again</a></p>

Hope it helps someone.

Find and replace in file and overwrite file doesn't work, it empties the file

When the shell sees > index.html in the command line it opens the file index.html for writing, wiping off all its previous contents.

To fix this you need to pass the -i option to sed to make the changes inline and create a backup of the original file before it does the changes in-place:

sed -i.bak s/STRING_TO_REPLACE/STRING_TO_REPLACE_IT/g index.html

Without the .bak the command will fail on some platforms, such as Mac OSX.

No Network Security Config specified, using platform default - Android Log

This occurs to the api 28 and above, because doesn't accept http anymore, you need to change if you want to accept http or localhost requests.

  1. Create an XML file Create XML file

  2. Add the following code on the new XML file you created Add base-config

  3. Add this on AndroidManifest.xml Add this code line

Git commit date

The show command may be what you want. Try

git show -s --format=%ci <commit>

Other formats for the date string are available as well. Check the manual page for details.

Refresh image with a new one at the same url

I had a requirement: 1) can't add any ?var=xx to the image 2) it should work cross-domain

I really like the #4 option in this answer with one but:

  • it has problems working with crossdomain reliably (and it requires touching the server code).

My quick and dirty way is:

  1. Create hidden iframe
  2. Load the current page to it (yeah the whole page)
  3. iframe.contentWindow.location.reload(true);
  4. Re-set the image source to itself

Here it is

function RefreshCachedImage() {
    if (window.self !== return; //prevent recursion
    var $img = $("#MYIMAGE");
    var src = $img.attr("src");
    var iframe = document.createElement("iframe"); = "none";
    iframe.src = window.location.href;
    setTimeout(function () {
        setTimeout(function () {
            $img.removeAttr("src").attr("src", src);
        }, 2000);
    }, 2000);

Yeah, I know, setTimeout... You have to change that to proper onload-events.

How can I simulate a click to an anchor tag?

None of the above solutions address the generic intention of the original request. What if we don't know the id of the anchor? What if it doesn't have an id? What if it doesn't even have an href parameter (e.g. prev/next icon in a carousel)? What if we want to apply the action to multiple anchors with different models in an agnostic fashion? Here's an example that does something instead of a click, then later simulates the click (for any anchor or other tag):

var clicker = null;
    clicker=$(this); // capture the clicked dom object
    /* ... do something ... */
    e.preventDefault(); // prevent original click action
clicker[0].click(); // this repeats the original click. [0] is necessary.

Best way to require all files from a directory in ruby?

If it's a directory relative to the file that does the requiring (e.g. you want to load all files in the lib directory):

Dir[File.dirname(__FILE__) + '/lib/*.rb'].each {|file| require file }

Edit: Based on comments below, an updated version:

Dir[File.join(__dir__, 'lib', '*.rb')].each { |file| require file }

Shell Script — Get all files modified after <date>

This script will find files having a modification date of two minutes before and after the given date (and you can change the values in the conditions as per your requirement)


TODAY=$(date  -d "$(date +%F)" +%s)
TODAY_TIME=$(date -d "$(date +%T)" +%s)

for f in `ls`;
#       echo "File -> $f"
        MOD_DATE=$(stat -c %y "$f")
        MOD_DATE=${MOD_DATE% *}
#       echo MOD_DATE: $MOD_DATE
        MOD_DATE1=$(date -d "$MOD_DATE" +%s)
#       echo MOD_DATE: $MOD_DATE

if [[ ($DIFF_IN_DATE -ge -120) && ($DIFF_IN_DATE1 -le 120) && (DIFF_IN_DATE1 -ge -120) ]]
echo File lies in Next Hour = $f

#mv $PATH_SRC/$f  $PATH_DST/$f

For example you want files having modification date before the given date only, you may change 120 to 0 in $DIFF_IN_DATE parameter discarding the conditions of $DIFF_IN_DATE1 parameter.

Similarly if you want files having modification date 1 hour before and after given date, just replace 120 by 3600 in if CONDITION.

python for increment inner loop

You might just be better of using while loops rather than for loops for this. I translated your code directly from the java code.

str1 = "ababa"
str2 = "aba"
i = 0

while i < len(str1):
  j = 0
  while j < len(str2):
    if not str1[i+j] == str1[j]:
    if j == (len(str2) -1):
      i += len(str2)

How do I Alter Table Column datatype on more than 1 column?

ALTER TABLE can do multiple table alterations in one statement, but MODIFY COLUMN can only work on one column at a time, so you need to specify MODIFY COLUMN for each column you want to change:

ALTER TABLE webstore.Store

Also, note this warning from the manual:

When you use CHANGE or MODIFY, column_definition must include the data type and all attributes that should apply to the new column, other than index attributes such as PRIMARY KEY or UNIQUE. Attributes present in the original definition but not specified for the new definition are not carried forward.

How to change line width in IntelliJ (from 120 character)

I didn't understand why my this didn't work but I found out that this setting is now also under the programming language itself at:

'Editor' | 'Code Style' | < your language > | 'Wrapping and Braces' | 'Right margin (columns)'

HttpContext.Current.Request.Url.Host what it returns?

The Host property will return the domain name you used when accessing the site. So, in your development environment, since you're requesting


It's returning localhost. You can break apart your URL like so:

Protocol: http
Host: localhost
Port: 950
PathAndQuery: /m/pages/SearchResults.aspx?search=knight&filter=kitchen

How do I add my new User Control to the Toolbox or a new Winform?

One way to get this error is trying to add a usercontrol to a form while the project is set to compile as x64. Visual Studio throws the unhelpful: "Failed to load toolbox item . It will be removed from the toolbox."

Workaround is to design with "Any CPU" and compile to x64 as necessary.


Why doesn't Java support unsigned ints?

As soon as signed and unsigned ints are mixed in an expression things start to get messy and you probably will lose information. Restricting Java to signed ints only really clears things up. I’m glad I don’t have to worry about the whole signed/unsigned business, though I sometimes do miss the 8th bit in a byte.

MySQL - How to increase varchar size of an existing column in a database without breaking existing data?

It's safe to increase the size of your varchar column. You won't corrupt your data.

If it helps your peace of mind, keep in mind, you can always run a database backup before altering your data structures.

By the way, correct syntax is:

ALTER TABLE table_name MODIFY col_name VARCHAR(10000)

Also, if the column previously allowed/did not allow nulls, you should add the appropriate syntax to the end of the alter table statement, after the column type.

What file uses .md extension and how should I edit them?

Markdown is just a text file which optionally has .md, or .markdown extensions. It can be converted to HTML. To know syntax of Markdown, Check out

GitHub Flavored Markdown.

You can use any text editor for markdown. If you are sublime text user, you can check out Markdown Preview plugin which will display the rendered markdown content in browser and updates whenever you change the markdown file.

Some of the online markdown editor

Why is my toFixed() function not working?

I tried function toFixed(2) many times. Every time console shows "toFixed() is not a function".

but how I resolved is By using Math.round()


if ($(this).attr('name') == 'time') {
    var value = parseFloat($(this).val());
    value = Math.round(value*100)/100; // 10 defines 1 decimals, 100 for 2, 1000 for 3

this thing surely works for me and it might help you guys too...

Configuration with name 'default' not found. Android Studio

Just a note on this question:

I had this exact error in my React Native app when trying to build to android. All you should have to do is $ npm i.

Python: How to increase/reduce the fontsize of x and y tick labels?

You can set the fontsize directly in the call to set_xticklabels and set_yticklabels (as noted in previous answers). This will only affect one Axes at a time.

ax.set_xticklabels(x_ticks, rotation=0, fontsize=8)
ax.set_yticklabels(y_ticks, rotation=0, fontsize=8)

You can also set the ticklabel font size globally (i.e. for all figures/subplots in a script) using rcParams:

import matplotlib.pyplot as plt


Or, equivalently:


Finally, if this is a setting that you would like to be set for all your matplotlib plots, you could also set these two rcParams in your matplotlibrc file:

xtick.labelsize      : 8 # fontsize of the x tick labels
ytick.labelsize      : 8 # fontsize of the y tick labels

String is immutable. What exactly is the meaning?

In your example, the variable a is just a reference to an instance of a string object. When you say a = "ty", you are not actually changing the string object, but rather pointing the reference at an entirely different instance of the string class.

How to forward declare a template class in namespace std?

Forward declaration should have complete template arguments list specified.

Visual Studio Post Build Event - Copy to Relative Directory Location

Here is what you want to put in the project's Post-build event command line:

copy /Y "$(TargetDir)$(ProjectName).dll" "$(SolutionDir)lib\$(ProjectName).dll"

EDIT: Or if your target name is different than the Project Name.

copy /Y "$(TargetDir)$(TargetName).dll" "$(SolutionDir)lib\$(TargetName).dll"

Getting next element while cycling through a list

You can use a pairwise cyclic iterator:

from itertools import izip, cycle, tee

def pairwise(seq):
    a, b = tee(seq)
    return izip(a, b)

for elem, next_elem in pairwise(cycle(li)):

What 'additional configuration' is necessary to reference a .NET 2.0 mixed mode assembly in a .NET 4.0 project?

Also i had this issue with the class library, If any one have the issue with the class library added to your main application. Just add

<startup useLegacyV2RuntimeActivationPolicy="true">

to you main application which would then be picked by the class library.

How to getElementByClass instead of GetElementById with JavaScript?

document.getElementsByClassName('CLASSNAME')[0].style.display = 'none';

Acyually by using getElementsByClassName, it returns an array of multiple classes. Because same class name could be used in more than one instance inside same HTML page. We use array element id to target the class we need, in my case, it's first instance of the given class name.So I've used [0]

Changing the selected option of an HTML Select element

Vanilla JavaScript

Using plain old JavaScript:

var val = "Fish";_x000D_
var sel = document.getElementById('sel');_x000D_
document.getElementById('btn').onclick = function() {_x000D_
  var opts = sel.options;_x000D_
  for (var opt, j = 0; opt = opts[j]; j++) {_x000D_
    if (opt.value == val) {_x000D_
      sel.selectedIndex = j;_x000D_
<select id="sel">_x000D_
<button id="btn">Select Fish</button>


But if you really want to use jQuery:

var val = 'Fish';
$('#btn').on('click', function() {

var val = 'Fish';_x000D_
$('#btn').on('click', function() {_x000D_
<script src=""></script>_x000D_
<select id="sel">_x000D_
<button id="btn">Select Fish</button>

jQuery - Using Value Attributes

In case your options have value attributes which differ from their text content and you want to select via text content:

<select id="sel">
    <option value="1">Cat</option>
    <option value="2">Dog</option>
    <option value="3">Fish</option>
    var val = 'Fish';
    $('#sel option:contains(' + val + ')').prop({selected: true});


But if you do have the above set up and want to select by value using jQuery, you can do as before:

var val = 3;

Modern DOM

For the browsers that support document.querySelector and the HTMLOptionElement::selected property, this is a more succinct way of accomplishing this task:

var val = 3;    
document.querySelector('#sel [value="' + val + '"]').selected = true;



<select data-bind="value: val">
    <option value="1">Cat</option>
    <option value="2">Dog</option>
    <option value="3">Fish</option>
    var viewModel = {
        val: ko.observable()



<template id="template" is="dom-bind">
    <select value="{{ val }}">
        <option value="1">Cat</option>
        <option value="2">Dog</option>
        <option value="3">Fish</option>
    template.val = 3;


Angular 2

Note: this has not been updated for the final stable release.

<app id="app">
    <select [value]="val">
        <option value="1">Cat</option>
        <option value="2">Dog</option>
        <option value="3">Fish</option>
    var App = ng.Component({selector: 'app'})
        .View({template: app.innerHTML})
        .Class({constructor:  function() {}});

    ng.bootstrap(App).then(function(app) {
        app._hostComponent.instance.val = 3;


Vue 2

<div id="app">
    <select v-model="val">
        <option value="1">Cat</option>
        <option value="2">Dog</option>
        <option value="3">Fish</option>
    var app = new Vue({
        el: '#app',
        data: {
                val: null,
        mounted: function() {
                this.val = 3;


Pythonic way to combine FOR loop and IF statement

I personally think this is the prettiest version:

a = [2,3,4,5,6,7,8,9,0]
xyz = [0,12,4,6,242,7,9]
for x in filter(lambda w: w in a, xyz):
  print x


if you are very keen on avoiding to use lambda you can use partial function application and use the operator module (that provides functions of most operators).

from operator import contains
from functools import partial
print(list(filter(partial(contains, a), xyz)))

not:first-child selector

div li~li {
    color: red;

Supports IE7

Get file size, image width and height before upload

Here is a pure JavaScript example of picking an image file, displaying it, looping through the image properties, and then re-sizing the image from the canvas into an IMG tag and explicitly setting the re-sized image type to jpeg.

If you right click the top image, in the canvas tag, and choose Save File As, it will default to a PNG format. If you right click, and Save File as the lower image, it will default to a JPEG format. Any file over 400px in width is reduced to 400px in width, and a height proportional to the original file.


<form class='frmUpload'>
  <input name="picOneUpload" type="file" accept="image/*" onchange="picUpload(this.files[0])" >

<canvas id="cnvsForFormat" width="400" height="266" style="border:1px solid #c3c3c3"></canvas>
<div id='allImgProperties' style="display:inline"></div>

<div id='imgTwoForJPG'></div>



window.picUpload = function(frmData) {
  console.log("picUpload ran: " + frmData);

var allObjtProperties = '';
for (objProprty in frmData) {
    console.log(objProprty + " : " + frmData[objProprty]);
    allObjtProperties = allObjtProperties + "<span>" + objProprty + ": " + frmData[objProprty] + ", </span>";

document.getElementById('allImgProperties').innerHTML = allObjtProperties;

var cnvs=document.getElementById("cnvsForFormat");
console.log("cnvs: " + cnvs);
var ctx=cnvs.getContext("2d");

var img = new Image;
img.src = URL.createObjectURL(frmData);

console.log('img: ' + img);

img.onload = function() {
  var picWidth = this.width;
  var picHeight = this.height;

  var wdthHghtRatio = picHeight/picWidth;
  console.log('wdthHghtRatio: ' + wdthHghtRatio);

  if (Number(picWidth) > 400) {
    var newHeight = Math.round(Number(400) * wdthHghtRatio);
  } else {
    return false;

    document.getElementById('cnvsForFormat').height = newHeight;
    console.log('width: 400  h: ' + newHeight);
    //You must change the width and height settings in order to decrease the image size, but
    //it needs to be proportional to the original dimensions.
    console.log('This is BEFORE the DRAW IMAGE');
    ctx.drawImage(img,0,0, 400, newHeight);

    console.log('THIS IS AFTER THE DRAW IMAGE!');

    //Even if original image is jpeg, getting data out of the canvas will default to png if not specified
    var canvasToDtaUrl = cnvs.toDataURL("image/jpeg");
    //The type and size of the image in this new IMG tag will be JPEG, and possibly much smaller in size
    document.getElementById('imgTwoForJPG').innerHTML = "<img src='" + canvasToDtaUrl + "'>";


Here is a jsFiddle:

jsFiddle Pick, display, get properties, and Re-size an image file

In jsFiddle, right clicking the top image, which is a canvas, won't give you the same save options as right clicking the bottom image in an IMG tag.

How to get numeric value from a prompt box?

You can use parseInt() but, as mentioned, the radix (base) should be specified:

x = parseInt(x, 10);
y = parseInt(y, 10);

10 means a base-10 number.

See this link for an explanation of why the radix is necessary.

sqlalchemy IS NOT NULL select

Starting in version 0.7.9 you can use the filter operator .isnot instead of comparing constraints, like this:


This method is only necessary if pep8 is a concern.

source: sqlalchemy documentation

How to insert current_timestamp into Postgres via python

If you use psycopg2 (and possibly some other client library), you can simply pass a Python datetime object as a parameter to a SQL-query:

from datetime import datetime, timezone

dt =
cur.execute('INSERT INTO mytable (mycol) VALUES (%s)', (dt,))

(This assumes that the timestamp with time zone type is used on the database side.)

More Python types that can be adapted into SQL (and returned as Python objects when a query is executed) are listed here.

Count number of records returned by group by

you can also get by the below query

select column_group_by,count(*) as Coulm_name_to_be_displayed from Table group by Column;

-- For example:
select city,count(*) AS Count from people group by city

How do synchronized static methods work in Java and can I use it for loading Hibernate entities?

static synchronized means holding lock on the the class's Class object where as synchronized means holding lock on that class's object itself. That means, if you are accessing a non-static synchronized method in a thread (of execution) you still can access a static synchronized method using another thread.

So, accessing two same kind of methods(either two static or two non-static methods) at any point of time by more than a thread is not possible.

How to concatenate two IEnumerable<T> into a new IEnumerable<T>?

The Concat method will return an object which implements IEnumerable<T> by returning an object (call it Cat) whose enumerator will attempt to use the two passed-in enumerable items (call them A and B) in sequence. If the passed-in enumerables represent sequences which will not change during the lifetime of Cat, and which can be read from without side-effects, then Cat may be used directly. Otherwise, it may be a good idea to call ToList() on Cat and use the resulting List<T> (which will represent a snapshot of the contents of A and B).

Some enumerables take a snapshot when enumeration begins, and will return data from that snapshot if the collection is modified during enumeration. If B is such an enumerable, then any change to B which occurs before Cat has reached the end of A will show up in Cat's enumeration, but changes which occur after that will not. Such semantics may likely be confusing; taking a snapshot of Cat can avoid such issues.

Node/Express file upload

I find this, simple and efficient:

const express = require('express');
const fileUpload = require('express-fileupload');
const app = express();

// default options
app.use(fileUpload());'/upload', function(req, res) {
  if (!req.files || Object.keys(req.files).length === 0) {
    return res.status(400).send('No files were uploaded.');

  // The name of the input field (i.e. "sampleFile") is used to retrieve the uploaded file
  let sampleFile = req.files.sampleFile;

  // Use the mv() method to place the file somewhere on your server'/somewhere/on/your/server/filename.jpg', function(err) {
    if (err)
      return res.status(500).send(err);

    res.send('File uploaded!');


Compare two different files line by line in python

I have just been faced with the same challenge, but I thought "Why programming this in Python if you can solve it with a simple "grep"?, which led to the following Python code:

import subprocess
from subprocess import PIPE

  output1, errors1 = subprocess.Popen(["c:\\cygwin\\bin\\grep", "-Fvf" ,"c:\\file1.txt", "c:\\file2.txt"], shell=True, stdout=PIPE, stderr=PIPE).communicate();
  output2, errors2 = subprocess.Popen(["c:\\cygwin\\bin\\grep", "-Fvf" ,"c:\\file2.txt", "c:\\file1.txt"], shell=True, stdout=PIPE, stderr=PIPE).communicate();
  if (len(output1) + len(output2) + len(errors1) + len(errors2) > 0):
    print ("Compare result : There are differences:");
    if (len(output1) + len(output2) > 0):
      print ("  Output differences : ");
      print (output1);
      print (output2);
    if (len(errors1) + len(errors2) > 0):
      print (" Errors : ");
      print (errors1);
      print (errors2);
    print ("Compare result : Both files are equal");
except Exception as ex:
  print("Compare result : Exception during comparison");

The trick behind this is the following: grep -Fvf file1.txt file2.txt verifies if all entries in file2.txt are present in file1.txt. By doing this in both directions we can see if the content of both files are "equal". I put "equal" between quotes because duplicate lines are disregarded in this way of working.

Obviously, this is just an example: you can replace grep by any commandline file comparison tool.

Event handlers for Twitter Bootstrap dropdowns?

I have been looking at this. On populating the drop down anchors, I have given them a class and data attributes, so when needing to do an action you can do:

<li><a class="dropDownListItem" data-name="Fred Smith" href="#">Fred</a></li>

and then in the jQuery doing something like:

$('.dropDownListItem').click(function(e) {
    var name = e.currentTarget;

So if you have dynamically generated list items in your dropdown and need to use the data that isn't just the text value of the item, you can use the data attributes when creating the dropdown listitem and then just give each item with the class the event, rather than referring to the id's of each item and generating a click event.

How to add checkboxes to JTABLE swing

1) JTable knows JCheckbox with built-in Boolean TableCellRenderers and TableCellEditor by default, then there is contraproductive declare something about that,

2) AbstractTableModel should be useful, where is in the JTable required to reduce/restrict/change nested and inherits methods by default implemented in the DefaultTableModel,

3) consider using DefaultTableModel, (if you are not sure about how to works) instead of AbstractTableModel,


could be generated from simple code:

import javax.swing.*;
import javax.swing.table.*;

public class TableCheckBox extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTable table;

    public TableCheckBox() {
        Object[] columnNames = {"Type", "Company", "Shares", "Price", "Boolean"};
        Object[][] data = {
            {"Buy", "IBM", new Integer(1000), new Double(80.50), false},
            {"Sell", "MicroSoft", new Integer(2000), new Double(6.25), true},
            {"Sell", "Apple", new Integer(3000), new Double(7.35), true},
            {"Buy", "Nortel", new Integer(4000), new Double(20.00), false}
        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        table = new JTable(model) {

            private static final long serialVersionUID = 1L;

            public Class getColumnClass(int column) {
            return getValueAt(0, column).getClass();
            public Class getColumnClass(int column) {
                switch (column) {
                    case 0:
                        return String.class;
                    case 1:
                        return String.class;
                    case 2:
                        return Integer.class;
                    case 3:
                        return Double.class;
                        return Boolean.class;
        JScrollPane scrollPane = new JScrollPane(table);

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            public void run() {
                TableCheckBox frame = new TableCheckBox();
                frame.setLocation(150, 150);

How do I turn a C# object into a JSON string in .NET?

You could use the JavaScriptSerializer class (add reference to System.Web.Extensions):

using System.Web.Script.Serialization;
var json = new JavaScriptSerializer().Serialize(obj);

A full example:

using System;
using System.Web.Script.Serialization;

public class MyDate
    public int year;
    public int month;
    public int day;

public class Lad
    public string firstName;
    public string lastName;
    public MyDate dateOfBirth;

class Program
    static void Main()
        var obj = new Lad
            firstName = "Markoff",
            lastName = "Chaney",
            dateOfBirth = new MyDate
                year = 1901,
                month = 4,
                day = 30
        var json = new JavaScriptSerializer().Serialize(obj);

generate a random number between 1 and 10 in c


int nRandonNumber = rand()%((nMax+1)-nMin) + nMin;

SSRS chart does not show all labels on Horizontal axis

The problem here is that if there are too many data bars the labels will not show.

To fix this, under the "Chart Axis" properties set the Interval value to "=1". Then all the labels will be shown.

How do I use System.getProperty("line.separator").toString()?

The problem

You must NOT assume that an arbitrary input text file uses the "correct" platform-specific newline separator. This seems to be the source of your problem; it has little to do with regex.

To illustrate, on the Windows platform, System.getProperty("line.separator") is "\r\n" (CR+LF). However, when you run your Java code on this platform, you may very well have to deal with an input file whose line separator is simply "\n" (LF). Maybe this file was originally created in Unix platform, and then transferred in binary (instead of text) mode to Windows. There could be many scenarios where you may run into these kinds of situations, where you must parse a text file as input which does not use the current platform's newline separator.

(Coincidentally, when a Windows text file is transferred to Unix in binary mode, many editors would display ^M which confused some people who didn't understand what was going on).

When you are producing a text file as output, you should probably prefer the platform-specific newline separator, but when you are consuming a text file as input, it's probably not safe to make the assumption that it correctly uses the platform specific newline separator.

The solution

One way to solve the problem is to use e.g. java.util.Scanner. It has a nextLine() method that can return the next line (if one exists), correctly handling any inconsistency between the platform's newline separator and the input text file.

You can also combine 2 Scanner, one to scan the file line by line, and another to scan the tokens of each line. Here's a simple usage example that breaks each line into a List<String>. The entire file therefore becomes a List<List<String>>.

This is probably a better approach than reading the entire file into one huge String and then split into lines (which are then split into parts).

    String text
        = "row1\tblah\tblah\tblah\n"
        + "row2\t1\t2\t3\t4\r\n"
        + "row3\tA\tB\tC\r"
        + "row4";

    //  row1    blah    blah    blah
    //  row2    1   2   3   4
    //  row3    A   B   C
    //  row4

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

    Scanner sc = new Scanner(text);
    while (sc.hasNextLine()) {
        Scanner lineSc = new Scanner(sc.nextLine()).useDelimiter("\t");
        List<String> line = new ArrayList<String>();
        while (lineSc.hasNext()) {
    // [[row1, blah, blah, blah], [row2, 1, 2, 3, 4], [row3, A, B, C], [row4]]

See also

  • Effective Java 2nd Edition, Item 25: Prefer lists to arrays

Related questions

How to convert milliseconds to seconds with precision

Surely you just need:

double seconds = milliseconds / 1000.0;

There's no need to manually do the two parts separately - you just need floating point arithmetic, which the use of 1000.0 (as a double literal) forces. (I'm assuming your milliseconds value is an integer of some form.)

Note that as usual with double, you may not be able to represent the result exactly. Consider using BigDecimal if you want to represent 100ms as 0.1 seconds exactly. (Given that it's a physical quantity, and the 100ms wouldn't be exact in the first place, a double is probably appropriate, but...)

Setting up Vim for Python

Re: the dead "Turning Vim Into A Modern Python IDE" link, back in 2013 I saved a copy, that I converted to a HTML page as well as a PDF copy:

Edit (Sep 08, 2017) updated URLs.

Calling Python in Java?

It's not smart to have python code inside java. Wrap your python code with flask or other web framework to make it as a microservice. Make your java program able to call this microservice (e.g. via REST).

Beleive me, this is much simple and will save you tons of issues. And the codes are loosely coupled so they are scalable.

Updated on Mar 24th 2020: According to @stx's comment, the above approach is not suitable for massive data transfer between client and server. Here is another approach I recommended: Connecting Python and Java with Rust(C/C++ also ok).

What's the best way to add a drop shadow to my UIView

You can set shadow to your view from storyboard also

enter image description here

How can I access each element of a pair in a pair list?

You can access the members by their index in the tuple.

lst = [(1,'on'),(2,'onn'),(3,'onnn'),(4,'onnnn'),(5,'onnnnn')]

def unFld(x):

    for i in x:
        print(i[0],' ',i[1])


Output :

1    on

2    onn

3    onnn

4    onnnn

5    onnnnn

Docker-compose: node_modules not present in a volume after npm install succeeds

In my opinion, we should not RUN npm install in the Dockerfile. Instead, we can start a container using bash to install the dependencies before runing the formal node service

docker run -it -v ./app:/usr/src/app  your_node_image_name  /bin/bash
root@247543a930d6:/usr/src/app# npm install

Append an array to another array in JavaScript

If you want to modify the original array instead of returning a new array, use .push()...

array1.push.apply(array1, array2);
array1.push.apply(array1, array3);

I used .apply to push the individual members of arrays 2 and 3 at once.


array1.push.apply(array1, array2.concat(array3));

To deal with large arrays, you can do this in batches.

for (var n = 0, to_add = array2.concat(array3); n < to_add.length; n+=300) {
    array1.push.apply(array1, to_add.slice(n, n+300));

If you do this a lot, create a method or function to handle it.

var push_apply = Function.apply.bind([].push);
var slice_call =[].slice);

Object.defineProperty(Array.prototype, "pushArrayMembers", {
    value: function() {
        for (var i = 0; i < arguments.length; i++) {
            var to_add = arguments[i];
            for (var n = 0; n < to_add.length; n+=300) {
                push_apply(this, slice_call(to_add, n, n+300));

and use it like this:

array1.pushArrayMembers(array2, array3);

var push_apply = Function.apply.bind([].push);_x000D_
var slice_call =[].slice);_x000D_
Object.defineProperty(Array.prototype, "pushArrayMembers", {_x000D_
    value: function() {_x000D_
        for (var i = 0; i < arguments.length; i++) {_x000D_
            var to_add = arguments[i];_x000D_
            for (var n = 0; n < to_add.length; n+=300) {_x000D_
                push_apply(this, slice_call(to_add, n, n+300));_x000D_
var array1 = ['a','b','c'];_x000D_
var array2 = ['d','e','f'];_x000D_
var array3 = ['g','h','i'];_x000D_
array1.pushArrayMembers(array2, array3);_x000D_
document.body.textContent = JSON.stringify(array1, null, 4);

mongodb/mongoose findMany - find all documents with IDs listed in array

Use this format of querying

let arr = => new mongoose.Types.ObjectId(;

Item.find({ vendorId: mongoose.Types.ObjectId(_vendorId) , status:'Active'})

How to discard all changes made to a branch?

git reset --hard can help you if you want to throw away everything since your last commit

Installation failed with message Invalid File

I found its work by restarting my phone :)

Angles between two n-dimensional vectors in Python

For the few who may have (due to SEO complications) ended here trying to calculate the angle between two lines in python, as in (x0, y0), (x1, y1) geometrical lines, there is the below minimal solution (uses the shapely module, but can be easily modified not to):

from shapely.geometry import LineString
import numpy as np

ninety_degrees_rad = 90.0 * np.pi / 180.0

def angle_between(line1, line2):
    coords_1 = line1.coords
    coords_2 = line2.coords

    line1_vertical = (coords_1[1][0] - coords_1[0][0]) == 0.0
    line2_vertical = (coords_2[1][0] - coords_2[0][0]) == 0.0

    # Vertical lines have undefined slope, but we know their angle in rads is = 90° * p/180
    if line1_vertical and line2_vertical:
        # Perpendicular vertical lines
        return 0.0
    if line1_vertical or line2_vertical:
        # 90° - angle of non-vertical line
        non_vertical_line = line2 if line1_vertical else line1
        return abs((90.0 * np.pi / 180.0) - np.arctan(slope(non_vertical_line)))

    m1 = slope(line1)
    m2 = slope(line2)

    return np.arctan((m1 - m2)/(1 + m1*m2))

def slope(line):
    # Assignments made purely for readability. One could opt to just one-line return them
    x0 = line.coords[0][0]
    y0 = line.coords[0][1]
    x1 = line.coords[1][0]
    y1 = line.coords[1][1]
    return (y1 - y0) / (x1 - x0)

And the use would be

>>> line1 = LineString([(0, 0), (0, 1)]) # vertical
>>> line2 = LineString([(0, 0), (1, 0)]) # horizontal
>>> angle_between(line1, line2)
>>> np.degrees(angle_between(line1, line2))

c# open file with default application and parameters

If you want the file to be opened with the default application, I mean without specifying Acrobat or Reader, you can't open the file in the specified page.

On the other hand, if you are Ok with specifying Acrobat or Reader, keep reading:

You can do it without telling the full Acrobat path, like this:

Process myProcess = new Process();    
myProcess.StartInfo.FileName = "acroRd32.exe"; //not the full application path
myProcess.StartInfo.Arguments = "/A \"page=2=OpenActions\" C:\\example.pdf";

If you don't want the pdf to open with Reader but with Acrobat, chage the second line like this:

myProcess.StartInfo.FileName = "Acrobat.exe";

You can query the registry to identify the default application to open pdf files and then define FileName on your process's StartInfo accordingly.

Follow this question for details on doing that: Finding the default application for opening a particular file type on Windows

wordpress contactform7 textarea cols and rows change in smaller screens

In the documentaion

[textarea* message id:contact-message 10x2 placeholder "Your Message"]

The above will generate a textarea with cols="10" and rows="2"

<textarea name="message" cols="10" rows="2" class="wpcf7-form-control wpcf7-textarea wpcf7-validates-as-required" id="contact-message" aria-required="true" aria-invalid="false" placeholder="Your Message"></textarea>

no match for ‘operator<<’ in ‘std::operator

Obviously, the standard library provided operator does not know what to do with your user defined type mystruct. It only works for predefined data types. To be able to use it for your own data type, You need to overload operator << to take your user defined data type.

How to reload page every 5 seconds?

 <meta http-equiv="refresh" content="5; URL=">

If it has to be in the script use setTimeout like:

}, 5000);

How to resolve Value cannot be null. Parameter name: source in linq?

When you call a Linq statement like this:

// x = new List<string>();
var count = x.Count(s => s.StartsWith("x"));

You are actually using an extension method in the System.Linq namespace, so what the compiler translates this into is:

var count = Enumerable.Count(x, s => s.StartsWith("x"));

So the error you are getting above is because the first parameter, source (which would be x in the sample above) is null.

Get The Current Domain Name With Javascript (Not the path, etc.)

I figure it ought to be as simple as this:


How to create a connection string in c#

add this in web.config file

                 <add key="ConnectionString" value="Your connection string which contains database id and password"/>

.cs file

 public ConnectionObjects()
    string connectionstring= ConfigurationManager.AppSettings["ConnectionString"].ToString();

Hope this helps.

How to put a new line into a wpf TextBlock control?

Even though this is an old question, I've just come across the problem and solved it differently from the given answers. Maybe it could be helpful to others.

I noticed that even though my XML files looked like:

 <subTag>content with newline.\r\nto display</subTag>

When it was read into my C# code the string had double backslashes.


To fix this I wrote a ValueConverter to strip the extra backslash.

public class XmlStringConverter : IValueConverter
    public object Convert(
        object value,
        Type targetType,
        object parameter,
        CultureInfo culture)
        string valueAsString = value as string;
        if (string.IsNullOrEmpty(valueAsString))
            return value;

        valueAsString = valueAsString.Replace("\\r\\n", "\r\n");
        return valueAsString;

    public object ConvertBack(
        object value,
        Type targetType,
        object parameter,
        CultureInfo culture)
        throw new NotImplementedException();

Return HTTP status code 201 in flask

Ripping off Luc's comment here, but to return a blank response, like a 201 the simplest option is to use the following return in your route.

return "", 201

So for example:

    @app.route('/database', methods=["PUT"])
    def database():
        return "", 201

JavaScript variable assignments from tuples

I made a tuple implementation that works quite well. This solution allows for array destructuring, as well as basic type-cheking.

const Tuple = (function() {
    function Tuple() {
        // Tuple needs at least one element
        if (arguments.length < 1) {
            throw new Error('Tuple needs at least one element');

        const args = { ...arguments };

        // Define a length property (equal to the number of arguments provided)
        Object.defineProperty(this, 'length', {
            value: arguments.length,
            writable: false

        // Assign values to enumerable properties
        for (let i in args) {
            Object.defineProperty(this, i, {
                enumerable: true,
                get() {
                    return args[+i];
                // Checking if the type of the provided value matches that of the existing value
                set(value) {
                    if (typeof value !== typeof args[+i]) {
                        throw new Error('Cannot assign ' + typeof value + ' on ' + typeof args[+i]);

                    args[+i] = value;

        // Implementing iteration with Symbol.iterator (allows for array destructuring as well for...of loops)
        this[Symbol.iterator] = function() {
            const tuple = this;

            return {
                current: 0,
                last: tuple.length - 1,
                next() {
                    if (this.current <= this.last) {
                        let val = { done: false, value: tuple[this.current] };
                        return val;
                    } else {
                        return { done: true };

        // Sealing the object to make sure no more values can be added to tuple

    // check if provided object is a tuple
    Tuple.isTuple = function(obj) {
        return obj instanceof Tuple;

    // Misc. for making the tuple more readable when printing to the console
    Tuple.prototype.toString = function() {
        const copyThis = { ...this };
        const values = Object.values(copyThis);
        return `(${values.join(', ')})`;

    // conctat two instances of Tuple
    Tuple.concat = function(obj1, obj2) {
        if (!Tuple.isTuple(obj1) || !Tuple.isTuple(obj2)) {
            throw new Error('Cannot concat Tuple with ' + typeof (obj1 || obj2));

        const obj1Copy = { ...obj1 };
        const obj2Copy = { ...obj2 };

        const obj1Items = Object.values(obj1Copy);
        const obj2Items = Object.values(obj2Copy);

        return new Tuple(...obj1Items, ...obj2Items);

    return Tuple;

const SNAKE_COLOR = new Tuple(0, 220, 10);

const [red, green, blue] = SNAKE_COLOR;
console.log(green); // => 220

PHP: Inserting Values from the Form into MySQL

The following code just declares a string variable that contains a MySQL query:

$sql = "INSERT INTO users (username, password, email)
    VALUES ('".$_POST["username"]."','".$_POST["password"]."','".$_POST["email"]."')";

It does not execute the query. In order to do that you need to use some functions but let me explain something else first.

NEVER TRUST USER INPUT: You should never append user input (such as form input from $_GET or $_POST) directly to your query. Someone can carefully manipulate the input in such a way so that it can cause great damage to your database. That's called SQL Injection. You can read more about it here

To protect your script from such an attack you must use Prepared Statements. More on prepared statements here

Include prepared statements to your code like this:

$sql = "INSERT INTO users (username, password, email)
    VALUES (?,?,?)";

Notice how the ? are used as placeholders for the values. Next you should prepare the statement using mysqli_prepare:

$stmt = mysqli_prepare($sql);

Then start binding the input variables to the prepared statement:

$stmt->bind_param("sss", $_POST['username'], $_POST['email'], $_POST['password']);

And finally execute the prepared statements. (This is where the actual insertion takes place)


NOTE Although not part of the question, I strongly advice you to never store passwords in clear text. Instead you should use password_hash to store a hash of the password

C# Test if user has write access to a folder

I couldn't get GetAccessControl() to throw an exception on Windows 7 as recommended in the accepted answer.

I ended up using a variation of sdds's answer:

            bool writeable = false;
            WindowsPrincipal principal = new WindowsPrincipal(WindowsIdentity.GetCurrent());
            DirectorySecurity security = Directory.GetAccessControl(pstrPath);
            AuthorizationRuleCollection authRules = security.GetAccessRules(true, true, typeof(SecurityIdentifier));

            foreach (FileSystemAccessRule accessRule in authRules)

                if (principal.IsInRole(accessRule.IdentityReference as SecurityIdentifier))
                    if ((FileSystemRights.WriteData & accessRule.FileSystemRights) == FileSystemRights.WriteData)
                        if (accessRule.AccessControlType == AccessControlType.Allow)
                            writeable = true;
                        else if (accessRule.AccessControlType == AccessControlType.Deny)
                            //Deny usually overrides any Allow
                            return false;

            return writeable;
        catch (UnauthorizedAccessException)
            return false;

Hope this helps.

Javascript get Object property Name

I was searching to get a result for this either and I ended up with;

const MyObject = {
    SubObject: {
        'eu': [0, "asd", true, undefined],
        'us': [0, "asd", false, null],
        'aus': [0, "asd", false, 0]

For those who wanted the result as a string:


output: "eu,us,aus"

For those who wanted the result as an array:


output: Array ["eu", "us", "aus"]

For those who are looking for a "contains" type method: as numeric result:


output: -1


output: 0


output: 3

as boolean result:


output: true

In your case;

var myVar = { typeA: { option1: "one", option2: "two" } }_x000D_
    // Example 1_x000D_
    console.log(Object.keys(myVar.typeA).toString()); // Result: "option1, option2"_x000D_
    // Example 2_x000D_
    console.log(Array.from(Object.keys(myVar.typeA))); // Result: Array ["option1", "option2" ]_x000D_
    // Example 3 as numeric_x000D_
    console.log((Object.keys(myVar.typeA).indexOf("option1")>=0)?'Exist!':'Does not exist!'); // Result: Exist!_x000D_
    // Example 3 as boolean_x000D_
    console.log(Object.keys(myVar.typeA).includes("option2")); // Result: True!_x000D_
    // if you would like to know about SubObjects_x000D_
    for(var key in myVar){_x000D_
      // do smt with SubObject_x000D_
      console.log(key); // Result: typeA_x000D_
    // if you already know your "SubObject"_x000D_
    for(var key in myVar.typeA){_x000D_
      // do smt with option1, option2_x000D_
      console.log(key); // Result: option1 // Result: option2_x000D_

Python NoneType object is not callable (beginner)

You want to pass the function object hi to your loop() function, not the result of a call to hi() (which is None since hi() doesn't return anything).

So try this:

>>> loop(hi, 5)

Perhaps this will help you understand better:

>>> print hi()
>>> print hi
<function hi at 0x0000000002422648>

Add and remove multiple classes in jQuery

Add multiple classes:

$("p").addClass("class1 class2 class3");

or in cascade:


Very similar also to remove more classes:

$("p").removeClass("class1 class2 class3");

or in cascade:


Using lambda expressions for event handlers

EventHandler handler = (s, e) => MessageBox.Show("Woho");

button.Click += handler;
button.Click -= handler;

Programmatically get height of navigation bar

Swift 5

If you want to get the navigation bar height, use the maxY property that considers the safeArea size as well, like this:

 let height = navigationController?.navigationBar.frame.maxY  

Android: Difference between Parcelable and Serializable?

I am late in answer, but posting with hope that it will help others.

In terms of Speed, Parcelable > Serializable. But, Custom Serializable is exception. It is almost in range of Parcelable or even more faster.

Reference :

Example :

Custom Class to be serialized

class MySerialized implements Serializable { 

    String deviceAddress = "MyAndroid-04"; 

    transient String token = "AABCDS"; // sensitive information which I do not want to serialize

    private void writeObject(ObjectOutputStream oos) throws Exception {
        oos.writeObject("111111" + token); // Encrypted token to be serialized

    private void readObject(ObjectInputStream ois) throws Exception {
        token = ((String) ois.readObject()).subString(6);  // Decrypting token


How do I make a newline after a twitter bootstrap element?

I believe Twitter Bootstrap has a class called clearfix that you can use to clear the floating.

<ul class="nav nav-tabs span2 clearfix">

Printing the correct number of decimal points with cout

setprecision(n) applies to the entire number, not the fractional part. You need to use the fixed-point format to make it apply to the fractional part: setiosflags(ios::fixed)

How to calculate Date difference in Hive

If you need the difference in seconds (i.e.: you're comparing dates with timestamps, and not whole days), you can simply convert two date or timestamp strings in the format 'YYYY-MM-DD HH:MM:SS' (or specify your string date format explicitly) using unix_timestamp(), and then subtract them from each other to get the difference in seconds. (And can then divide by 60.0 to get minutes, or by 3600.0 to get hours, etc.)


UNIX_TIMESTAMP('2017-12-05 10:01:30') - UNIX_TIMESTAMP('2017-12-05 10:00:00') AS time_diff -- This will return 90 (seconds). Unix_timestamp converts string dates into BIGINTs. 

More on what you can do with unix_timestamp() here, including how to convert strings with different date formatting:

How to generate XML from an Excel VBA macro?

You might like to consider ADO - a worksheet or range can be used as a table.

Const adOpenStatic = 3
Const adLockOptimistic = 3
Const adPersistXML = 1

Set cn = CreateObject("ADODB.Connection")
Set rs = CreateObject("ADODB.Recordset")

''It wuld probably be better to use the proper name, but this is
''convenient for notes
strFile = Workbooks(1).FullName

''Note HDR=Yes, so you can use the names in the first row of the set
''to refer to columns, note also that you will need a different connection
''string for >=2007
strCon = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & strFile _
        & ";Extended Properties=""Excel 8.0;HDR=Yes;IMEX=1"";"

cn.Open strCon
rs.Open "Select * from [Sheet1$]", cn, adOpenStatic, adLockOptimistic

If Not rs.EOF Then
    rs.Save "C:\Docs\Table1.xml", adPersistXML
End If


How to handle floats and decimal separators with html5 input type number

According to the value attribute of the number input is defined as a floating-point number. The syntax of the floating-point number seems to only accept dots as decimal separators.

I've listed a few options below that might be helpful to you:

1. Using the pattern attribute

With the pattern attribute you can specify the allowed format with a regular expression in a HTML5 compatible way. Here you could specify that the comma character is allowed and a helpful feedback message if the pattern fails.

<input type="number" pattern="[0-9]+([,\.][0-9]+)?" name="my-num"
           title="The number input must start with a number and use either comma or a dot as a decimal character."/>

Note: Cross-browser support varies a lot. It may be complete, partial or non-existant..

2. JavaScript validation

You could try to bind a simple callback to for example the onchange (and/or blur) event that would either replace the comma or validate all together.

3. Disable browser validation ##

Thirdly you could try to use the formnovalidate attribute on the number inputs with the intention of disabling browser validation for that field all together.

<input type="number" formnovalidate />

4. Combination..?

<input type="number" pattern="[0-9]+([,\.][0-9]+)?" 
           name="my-num" formnovalidate
           title="The number input must start with a number and use either comma or a dot as a decimal character."/>

Why doesn't the Scanner class have a nextChar method?

The reason is that the Scanner class is designed for reading in whitespace-separated tokens. It's a convenience class that wraps an underlying input stream. Before scanner all you could do was read in single bytes, and that's a big pain if you want to read words or lines. With Scanner you pass in, and it does a number of read() operations to tokenize the input for you. Reading a single character is a more basic operation. Source

You can use (char);.

How to run java application by .bat file

Sure, call the java executable.

Mine is C:\Program Files\Java\jre6\bin\java.exe, so to run it I would do

C:\Program Files\Java\jre6\bin\java.exe -jar myjarfile.jar

org.json.simple cannot be resolved

The jar file is missing. You can download the jar file and add it as external libraries in your project . You can download this from

Could not open ServletContext resource [/WEB-INF/applicationContext.xml]

ContextLoaderListener has its own context which is shared by all servlets and filters. By default it will search /WEB-INF/applicationContext.xml

You can customize this by using


on web.xml, or remove this listener if you don't need one.


Since you want to pivot multiple columns of data, I would first suggest unpivoting the result, score and grade columns so you don't have multiple columns but you will have multiple rows.

Depending on your version of SQL Server you can use the UNPIVOT function or CROSS APPLY. The syntax to unpivot the data will be similar to:

select ratio, col, value
cross apply
  select 'result', cast(result as varchar(10)) union all
  select 'score', cast(score as varchar(10)) union all
  select 'grade', grade
) c(col, value)

See SQL Fiddle with Demo. Once the data has been unpivoted, then you can apply the PIVOT function:

select ratio = col,
  [current ratio], [gearing ratio], [performance ratio], total
  select ratio, col, value
  cross apply
    select 'result', cast(result as varchar(10)) union all
    select 'score', cast(score as varchar(10)) union all
    select 'grade', grade
  ) c(col, value)
) d
  for ratio in ([current ratio], [gearing ratio], [performance ratio], total)
) piv;

See SQL Fiddle with Demo. This will give you the result:

|  grade |          Good |          Good |      Satisfactory |      Good |
| result |       1.29400 |       0.33840 |           0.04270 |    (null) |
|  score |      60.00000 |      70.00000 |          50.00000 | 180.00000 |

Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.10:test

Update the Maven project:


  1. Right-click on "project"
  2. Go to "Maven" >> "Update"
  3. Wait for all the changes to be applied
  4. Commit the changes (if code is on repo)
  5. Run

Exception 'open failed: EACCES (Permission denied)' on Android

The post 6.0 enforcement of storage permissions can be bypassed if you have a rooted device via these adb commands:

root@msm8996:/ # getenforce
root@msm8996:/ # setenforce 0
setenforce 0
root@msm8996:/ # getenforce

Delete files or folder recursively on Windows CMD

For hidden files I had to use the following:

DEL /S /Q /A:H Thumbs.db

Convert pandas dataframe to NumPy array

df.to_numpy() is better than df.values, here's why.*

It's time to deprecate your usage of values and as_matrix().

pandas v0.24.0 introduced two new methods for obtaining NumPy arrays from pandas objects:

  1. to_numpy(), which is defined on Index, Series, and DataFrame objects, and
  2. array, which is defined on Index and Series objects only.

If you visit the v0.24 docs for .values, you will see a big red warning that says:

Warning: We recommend using DataFrame.to_numpy() instead.

See this section of the v0.24.0 release notes, and this answer for more information.

* - to_numpy() is my recommended method for any production code that needs to run reliably for many versions into the future. However if you're just making a scratchpad in jupyter or the terminal, using .values to save a few milliseconds of typing is a permissable exception. You can always add the fit n finish later.

Towards Better Consistency: to_numpy()

In the spirit of better consistency throughout the API, a new method to_numpy has been introduced to extract the underlying NumPy array from DataFrames.

# Setup
df = pd.DataFrame(data={'A': [1, 2, 3], 'B': [4, 5, 6], 'C': [7, 8, 9]}, 
                  index=['a', 'b', 'c'])

# Convert the entire DataFrame
# array([[1, 4, 7],
#        [2, 5, 8],
#        [3, 6, 9]])

# Convert specific columns
df[['A', 'C']].to_numpy()
# array([[1, 7],
#        [2, 8],
#        [3, 9]])

As mentioned above, this method is also defined on Index and Series objects (see here).

# array(['a', 'b', 'c'], dtype=object)

#  array([1, 2, 3])

By default, a view is returned, so any modifications made will affect the original.

v = df.to_numpy()
v[0, 0] = -1
   A  B  C
a -1  4  7
b  2  5  8
c  3  6  9

If you need a copy instead, use to_numpy(copy=True).

pandas >= 1.0 update for ExtensionTypes

If you're using pandas 1.x, chances are you'll be dealing with extension types a lot more. You'll have to be a little more careful that these extension types are correctly converted.

a = pd.array([1, 2, None], dtype="Int64")                                  

[1, 2, <NA>]
Length: 3, dtype: Int64 

# Wrong
# array([1, 2, <NA>], dtype=object)  # yuck, objects

# Correct
a.to_numpy(dtype='float', na_value=np.nan)                                 
# array([ 1.,  2., nan])

# Also correct
a.to_numpy(dtype='int', na_value=-1)
# array([ 1,  2, -1])

This is called out in the docs.

If you need the dtypes in the result...

As shown in another answer, DataFrame.to_records is a good way to do this.

# rec.array([('a', 1, 4, 7), ('b', 2, 5, 8), ('c', 3, 6, 9)],
#           dtype=[('index', 'O'), ('A', '<i8'), ('B', '<i8'), ('C', '<i8')])

This cannot be done with to_numpy, unfortunately. However, as an alternative, you can use np.rec.fromrecords:

v = df.reset_index()
np.rec.fromrecords(v, names=v.columns.tolist())
# rec.array([('a', 1, 4, 7), ('b', 2, 5, 8), ('c', 3, 6, 9)],
#           dtype=[('index', '<U1'), ('A', '<i8'), ('B', '<i8'), ('C', '<i8')])

Performance wise, it's nearly the same (actually, using rec.fromrecords is a bit faster).

df2 = pd.concat([df] * 10000)

%timeit df2.to_records()
v = df2.reset_index()
np.rec.fromrecords(v, names=v.columns.tolist())

12.9 ms ± 511 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
9.56 ms ± 291 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)

Rationale for Adding a New Method

to_numpy() (in addition to array) was added as a result of discussions under two GitHub issues GH19954 and GH23623.

Specifically, the docs mention the rationale:

[...] with .values it was unclear whether the returned value would be the actual array, some transformation of it, or one of pandas custom arrays (like Categorical). For example, with PeriodIndex, .values generates a new ndarray of period objects each time. [...]

to_numpy aims to improve the consistency of the API, which is a major step in the right direction. .values will not be deprecated in the current version, but I expect this may happen at some point in the future, so I would urge users to migrate towards the newer API, as soon as you can.

Critique of Other Solutions

DataFrame.values has inconsistent behaviour, as already noted.

DataFrame.get_values() is simply a wrapper around DataFrame.values, so everything said above applies.

DataFrame.as_matrix() is deprecated now, do NOT use!

Remove all git files from a directory?

You can use git-archive, for example:

git archive master | bzip2 > project.tar.bz2

Where master is the desired branch.

Question mark and colon in statement. What does it mean?

This is also known as the "inline if", or as above the ternary operator.

It's used to reduce code, though it's not recommended to use a lot of these on a single line as it may make maintaining code quite difficult. Imagine:

a = b?c:(d?e:(f?g:h));

and you could go on a while.

It ends up basically the same as writing:

  a = c;
else if(d)
  a = e;
else if(f)
  a = g;
  a = h;

In your case, "string requestUri = _apiURL + "?e=" + OperationURL[0] + ((OperationURL[1] == "GET") ? GetRequestSignature() : "");"

Can also be written as: (omitting the else, since it's an empty string)

string requestUri = _apiURL + "?e=" + OperationURL[0];
if((OperationURL[1] == "GET")
    requestUri = requestUri + GetRequestSignature();

or like this:

string requestUri;
if((OperationURL[1] == "GET")
    requestUri = _apiURL + "?e=" + OperationURL[0] + GetRequestSignature();
    requestUri = _apiURL + "?e=" + OperationURL[0];

Depending on your preference / the code style your boss tells you to use.

Delete all objects in a list

Here's how you delete every item from a list.

del c[:]

Here's how you delete the first two items from a list.

del c[:2]

Here's how you delete a single item from a list (a in your case), assuming c is a list.

del c[0]

Copy directory contents into a directory with python

The python libs are obsolete with this function. I've done one that works correctly:

import os
import shutil

def copydirectorykut(src, dst):
    nom= src+'.txt'
    fitx= open(nom, 'w')

    for item in list:
        fitx.write("%s\n" % item)


    f = open(nom,'r')
    for line in f.readlines():
        if "." in line:
            if not os.path.exists(dst+'/'+line[:-1]):

Warning "Do not Access Superglobal $_POST Array Directly" on Netbeans 7.4 for PHP

Although a bit late, I've come across this question while searching the solution for the same problem, so I hope it can be of any help...

Found myself in the same darkness than you. Just found this article, which explains some new hints introduced in NetBeans 7.4, including this one:

The reason why it has been added is because superglobals usually are filled with user input, which shouldn't ever be blindly trusted. Instead, some kind of filtering should be done, and that's what the hint suggests. Filter the superglobal value in case it has some poisoned content.

For instance, where I had:


I've put instead:


You have the filter_input and filters doc here:

Does overflow:hidden applied to <body> work on iPhone Safari?

Combining the answers and comments here and this similar question here worked for me.

So posting as a whole answer.

Here's how you need to put a wrapper div around your site content, just inside the <body> tag.

     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
     <!-- other meta and head stuff here -->
     <div class="wrapper">
         <!-- Your site content here -->

Create the wrapper class as below.

    position:relative; //that's it

I also got the idea from this answer here.

And this answer here also has got some food for thought. Something that probably will work equally good in both desktops and devices.

C++ code file extension? .cc vs .cpp

GNU GCC recognises all of the following as C++ files, and will use C++ compilation regardless of whether you invoke it through gcc or g++: .C, .cc, .cpp, .CPP, .c++, .cp, or .cxx.

Note the .C - case matters in GCC, .c is a C file whereas .C is a C++ file (if you let the compiler decide what it is compiling that is).

GCC also supports other suffixes to indicate special handling, for example a .ii file will be compiled as C++, but not pre-processed (intended for separately pre-processed code). All the recognised suffixes are detailed at

How do I open a new fragment from another fragment?

 Fragment fr = new Fragment_class();
             FragmentManager fm = getFragmentManager();
            FragmentTransaction fragmentTransaction = fm.beginTransaction();
            fragmentTransaction.add(, fr);

Just to be precise, is cretaed in your current class layout, upon calling, the new fragment automatically gets infiltrated.

IE and Edge fix for object-fit: cover;

I just used the @misir-jafarov and is working now with :

  • IE 8,9,10,11 and EDGE detection
  • used in Bootrap 4
  • take the height of its parent div
  • cliped vertically at 20% of top and horizontally 50% (better for portraits)

here is my code :

if (document.documentMode || /Edge/.test(navigator.userAgent)) {
    jQuery('.art-img img').each(function(){
        var t = jQuery(this),
            s = 'url(' + t.attr('src') + ')',
            p = t.parent(),
            d = jQuery('<div></div>');

            'height'                : t.parent().css('height'),
            'background-size'       : 'cover',
            'background-repeat'     : 'no-repeat',
            'background-position'   : '50% 20%',
            'background-image'      : s

Hope it helps.

Deploy a project using Git push

Sounds like you should have two copies on your server. A bare copy, that you can push/pull from, which your would push your changes when you're done, and then you would clone this into you web directory and set up a cronjob to update git pull from your web directory every day or so.

Where to install Android SDK on Mac OS X?

The easiest (and standard) way to install Android SDK under OS X is to use brew.

brew install android-sdk

If you do not have homebrew, here's how to get it.

This will install Android SDK into /usr/local/Cellar/android-sdk/ and, at this moment, this is the best location to install it.

In React Native, how do I put a view on top of another view, with part of it lying outside the bounds of the view behind?

The above solutions were not working for me. I solved it by creating a View with the same background colour as the parent and added negative margin to move the image upwards.

<ScrollView style={{ backgroundColor: 'blue' }}>
      width: '95%',
      paddingLeft: '5%',
      marginTop: 80,
      height: 800,
    <View style={{ backgroundColor: 'white' }}>

      <Thumbnail square large source={{uri: uri}} style={{ marginTop: -30 }}/>
      <Text>Some Text</Text>

and I got the following result.

enter image description here

Apply a theme to an activity in Android?

To set it programmatically in

public void onCreate(Bundle savedInstanceState) {


  setTheme(; // (for Custom theme)
  setTheme(; // (for Android Built In Theme)


To set in Application scope in Manifest.xml (all activities):


To set in Activity scope in Manifest.xml (single activity):


To build a custom theme, you will have to declare theme in themes.xml file, and set styles in styles.xml file.

org.apache.jasper.JasperException: Unable to compile class for JSP:

There's no need to manually put class files on Tomcat. Just make sure your package declaration for Member is correctly defined as

package pageNumber;

since, that's the only application package you're importing in your JSP.

<%@ page import="pageNumber.*, java.util.*,*" %>

Can I assume (bool)true == (int)1 for any C++ compiler?

I've found different compilers return different results on true. I've also found that one is almost always better off comparing a bool to a bool instead of an int. Those ints tend to change value over time as your program evolves and if you assume true as 1, you can get bitten by an unrelated change elsewhere in your code.

Can Selenium WebDriver open browser windows silently in the background?

Use it ...

from selenium import webdriver
from import Options

options = Options()
options.headless = True
driver = webdriver.Chrome(CHROMEDRIVER_PATH, chrome_options=options)

Read XML file using javascript

You can do something like this to read your nodes.

Also you can find some explanation in this page

<script type="text/javascript">
        var markers = null;
        $(document).ready(function () {
            $.get("File.xml", {}, function (xml){
                 markers = $(this);

Subtract days from a DateTime

The dateTime.AddDays(-1) does not subtract that one day from the dateTime reference. It will return a new instance, with that one day subtracted from the original reference.

DateTime dateTime = DateTime.Now;
DateTime otherDateTime = dateTime.AddDays(-1);

Nested ng-repeat

If you have a big nested JSON object and using it across several screens, you might face performance issues in page loading. I always go for small individual JSON objects and query the related objects as lazy load only where they are required.

you can achieve it using ng-init

<td class="lectureClass" ng-repeat="s in sessions" ng-init='presenters=getPresenters('>
      <div class="presenterClass" ng-repeat="p in presenters">

The code on the controller side should look like below

$scope.getPresenters = function(id) {
    return SessionPresenters.get({id: id});

While the API factory is as follows:

angular.module('tryme3App').factory('SessionPresenters', function ($resource, DateUtils) {

        return $resource('api/session.Presenters/:id', {}, {
            'query': { method: 'GET', isArray: true},
            'get': {
                method: 'GET', isArray: true
            'update': { method:'PUT' }

In Excel, how do I extract last four letters of a ten letter string?

No need to use a macro. Supposing your first string is in A1.

=RIGHT(A1, 4)

Drag this down and you will get your four last characters.

Edit: To be sure, if you ever have sequences like 'ABC DEF' and want the last four LETTERS and not CHARACTERS you might want to use trimspaces()


Edit: As per brettdj's suggestion, you may want to check that your string is actually 4-character long or more:


How can I return the current action in an ASP.NET MVC view?

In the RC you can also extract route data like the action method name like this


Update for MVC 3


Update for MVC 4


Update for MVC 4.5


How to append something to an array?

If you're only appending a single variable, then push() works just fine. If you need to append another array, use concat():

var ar1 = [1, 2, 3];_x000D_
var ar2 = [4, 5, 6];_x000D_
var ar3 = ar1.concat(ar2);_x000D_

The concat does not affect ar1 and ar2 unless reassigned, for example:

var ar1 = [1, 2, 3];_x000D_
var ar2 = [4, 5, 6];_x000D_
ar1 = ar1.concat(ar2);_x000D_

Lots of great info here.

Clearing state es6 React

The solutions that involve setting this.state directly aren't working for me in React 16, so here is what I did to reset each key:

  const initialState = { example: 'example' }
  constructor() {
      this.state = initialState
  reset() {
    const keys = Object.keys(this.state)
    const stateReset = keys.reduce((acc, v) => ({ ...acc, [v]: undefined }), {})
    this.setState({ ...stateReset, ...initialState })

WCF Service, the type provided as the service attribute values…could not be found

I also had same problem. Purposely my build output path was "..\bin" and it works for me when I set the build output path as "\bin".

event Action<> vs event EventHandler<>

The main difference will be that if you use Action<> your event will not follow the design pattern of virtually any other event in the system, which I would consider a drawback.

One upside with the dominating design pattern (apart from the power of sameness) is that you can extend the EventArgs object with new properties without altering the signature of the event. This would still be possible if you used Action<SomeClassWithProperties>, but I don't really see the point with not using the regular approach in that case.

redirect COPY of stdout to log file from within bash script itself

Solution for busybox, macOS bash, and non-bash shells

The accepted answer is certainly the best choice for bash. I'm working in a Busybox environment without access to bash, and it does not understand the exec > >(tee log.txt) syntax. It also does not do exec >$PIPE properly, trying to create an ordinary file with the same name as the named pipe, which fails and hangs.

Hopefully this would be useful to someone else who doesn't have bash.

Also, for anyone using a named pipe, it is safe to rm $PIPE, because that unlinks the pipe from the VFS, but the processes that use it still maintain a reference count on it until they are finished.

Note the use of $* is not necessarily safe.


if [ "$SELF_LOGGING" != "1" ]
    # The parent process will enter this branch and set up logging

    # Create a named piped for logging the child's output
    mkfifo $PIPE

    # Launch the child process with stdout redirected to the named pipe
    SELF_LOGGING=1 sh $0 $* >$PIPE &

    # Save PID of child process

    # Launch tee in a separate process
    tee logfile <$PIPE &

    # Unlink $PIPE because the parent process no longer needs it
    rm $PIPE    

    # Wait for child process, which is running the rest of this script
    wait $PID

    # Return the error code from the child process
    exit $?

# The rest of the script goes here

Rename a column in MySQL

In Server version: 5.6.34 MySQL Community Server

ALTER TABLE table_name
CHANGE COLUMN old_column_name new_column_name data_type;

How to strip HTML tags from string in JavaScript?

cleanText = strInputCode.replace(/<\/?[^>]+(>|$)/g, "");

Distilled from this website (web.achive).

This regex looks for <, an optional slash /, one or more characters that are not >, then either > or $ (the end of the line)


'<div>Hello</div>' ==> 'Hello'
 ^^^^^     ^^^^^^
'Unterminated Tag <b' ==> 'Unterminated Tag '

But it is not bulletproof:

'If you are < 13 you cannot register' ==> 'If you are '
'<div data="score > 42">Hello</div>' ==> ' 42">Hello'
 ^^^^^^^^^^^^^^^^^^          ^^^^^^

If someone is trying to break your application, this regex will not protect you. It should only be used if you already know the format of your input. As other knowledgable and mostly sane people have pointed out, to safely strip tags, you must use a parser.

If you do not have acccess to a convenient parser like the DOM, and you cannot trust your input to be in the right format, you may be better off using a package like sanitize-html, and also other sanitizers are available.

How to update PATH variable permanently from Windows command line?

The documentation on how to do this can be found on MSDN. The key extract is this:

To programmatically add or modify system environment variables, add them to the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment registry key, then broadcast a WM_SETTINGCHANGE message with lParam set to the string "Environment". This allows applications, such as the shell, to pick up your updates.

Note that your application will need elevated admin rights in order to be able to modify this key.

You indicate in the comments that you would be happy to modify just the per-user environment. Do this by editing the values in HKEY_CURRENT_USER\Environment. As before, make sure that you broadcast a WM_SETTINGCHANGE message.

You should be able to do this from your Java application easily enough using the JNI registry classes.

jQuery $(this) keyword

When you perform an DOM query through jQuery like $('class-name') it actively searched the DOM for that element and returns that element with all the jQuery prototype methods attached.

When you're within the jQuery chain or event you don't have to rerun the DOM query you can use the context $(this). Like so:

$('.class-name').on('click', (evt) => {
    $(this).hide(); // does not run a DOM query
    $('.class-name').hide() // runs a DOM query

$(this) will hold the element that you originally requested. It will attach all the jQuery prototype methods again, but will not have to search the DOM again.

Some more information:

Web Performance with jQuery selectors

Quote from a web blog that doesn't exist anymore but I'll leave it in here for history sake:

In my opinion, one of the best jQuery performance tips is to minimize your use of jQuery. That is, find a balance between using jQuery and plain ol’ JavaScript, and a good place to start is with ‘this‘. Many developers use $(this) exclusively as their hammer inside callbacks and forget about this, but the difference is distinct:

When inside a jQuery method’s anonymous callback function, this is a reference to the current DOM element. $(this) turns this into a jQuery object and exposes jQuery’s methods. A jQuery object is nothing more than a beefed-up array of DOM elements.

php is null or empty?

check == vs ===

'' == NULL would return true
0 == NULL would return true
false == null would return true

where as

'' === NULL would return false
0 === NULL would return false
false === NULL would return false

How to upsert (update or insert) in SQL Server 2005

Try to check for existence:


    INSERT INTO dbo.Employee(Col1, ..., ColN)
    VALUES(Val1, .., ValN)


    UPDATE dbo.Employee
    SET Col1 = Val1, Col2 = Val2, ...., ColN = ValN
    WHERE ID = @SomeID

You could easily wrap this into a stored procedure and just call that stored procedure from the outside (e.g. from a programming language like C# or whatever you're using).

Update: either you can just write this entire statement in one long string (doable - but not really very useful) - or you can wrap it into a stored procedure:

CREATE PROCEDURE dbo.InsertOrUpdateEmployee
       @ID INT,
       @Name VARCHAR(50),
       @ItemName VARCHAR(50),  
       @ItemCatName VARCHAR(50),
       @ItemQty DECIMAL(15,2)
       INSERT INTO dbo.Table1(ID, Name, ItemName, ItemCatName, ItemQty)
       VALUES(@ID, @Name, @ItemName, @ItemCatName, @ItemQty)
       UPDATE dbo.Table1
       SET Name = @Name,
           ItemName = @ItemName,
           ItemCatName = @ItemCatName,
           ItemQty = @ItemQty
       WHERE ID = @ID

and then just call that stored procedure from your ADO.NET code

PANIC: Cannot find AVD system path. Please define ANDROID_SDK_ROOT (in windows 10)

Open Android Studio and under the Tools you will find the AVD manager. Click on it and ensure that you have a valid virtual device with the SDK downloaded (click "download" in the Actions column if shown). Then ensure that the correct virtual device is selected on the toolbar.

How to convert upper case letters to lower case

You can find more methods and functions related to Python strings in section 5.6.1. String Methods of the documentation.


DateTime.TryParseExact() rejecting valid formats

string DemoLimit = "02/28/2018";
 string pattern = "MM/dd/yyyy";
 CultureInfo enUS = new CultureInfo("en-US"); 
 DateTime.TryParseExact(DemoLimit, pattern, enUS, 
                     DateTimeStyles.AdjustToUniversal, out datelimit);

For more

NGinx Default public www location?

you can access file config nginx,you can see root /path. in this default of nginx apache at /var/www/html

What is The difference between ListBox and ListView

A ListView is basically like a ListBox (and inherits from it), but it also has a View property. This property allows you to specify a predefined way of displaying the items. The only predefined view in the BCL (Base Class Library) is GridView, but you can easily create your own.

Another difference is the default selection mode: it's Single for a ListBox, but Extended for a ListView

Find the greatest number in a list of numbers

Use max()

>>> l = [1, 2, 5]
>>> max(l)

Condition within JOIN or WHERE

For inner joins I have not really noticed a difference (but as with all performance tuning, you need to check against your database under your conditions).

However where you put the condition makes a huge difference if you are using left or right joins. For instance consider these two queries:

FROM dbo.Customers AS CUS 
LEFT JOIN dbo.Orders AS ORD 
ON CUS.CustomerID = ORD.CustomerID
WHERE ORD.OrderDate >'20090515'

FROM dbo.Customers AS CUS 
LEFT JOIN dbo.Orders AS ORD 
ON CUS.CustomerID = ORD.CustomerID
AND ORD.OrderDate >'20090515'

The first will give you only those records that have an order dated later than May 15, 2009 thus converting the left join to an inner join.

The second will give those records plus any customers with no orders. The results set is very different depending on where you put the condition. (Select * is for example purposes only, of course you should not use this in production code.)

The exception to this is when you want to see only the records in one table but not the other. Then you use the where clause for the condition not the join.

FROM dbo.Customers AS CUS 
LEFT JOIN dbo.Orders AS ORD 
ON CUS.CustomerID = ORD.CustomerID
WHERE ORD.OrderID is null

Getting error: Peer authentication failed for user "postgres", when trying to get pgsql working with rails

Many of the other answers pertain to settings in the various config files, and the ones pertaining to the pg_hba.conf do apply and are 100% correct. However, make sure you are modifying the correct config files.

As others have mentioned the config file locations can be overridden with various settings inside the main config file, as well as supplying a path to the main config file on the command line with the -D option.

You can use the following command while in a psql session to show where your config files are being read (assuming you can launch psql). This is just a troubleshooting step that can help some people:

select * from pg_settings where setting~'pgsql';  

You should also make sure that the home directory for your postgres user is where you expect it to be. I say this because it is quite easy to overlook this due to the fact that your prompt will display '~' instead of the actual path of your home directory, making it not so obvious. Many installations default the postgres user home directory to /var/lib/pgsql.

If it is not set to what it is supposed to be, stop the postgresql service and use the following command while logged in as root. Also make sure the postgres user is not logged into another session:

usermod -d /path/pgsql postgres

Finally make sure your PGDATA variable is set correctly by typing echo $PGDATA, which should output something similar to:


If it is not set, or shows something different from what you expect it to be, examine your startup or RC files such as .profile or .bash.rc - this will vary greatly depending on your OS and your shell. Once you have determined the correct startup script for your machine, you can insert the following:

export PGDATA=/path/pgsql/data

For my system, I placed this in /etc/profile.d/ so it was accessible for all users.

You should now be able to init the database as usual and all your psql path settings should be correct!

How to select last one week data from today's date

to select records for the last 7 days

WHERE Created_Date >= DATEADD(day, -7, GETDATE())

to select records for the current week

SET DATEFIRST 1 -- Define beginning of week as Monday

if you want to select records for last week instead of the last 7 days

SET DATEFIRST 1 -- Define beginning of week as Monday

Enable IIS7 gzip

under windows 2012 r2 it can be found here:

enter image description here

Is there a common Java utility to break a list into batches?

Here an example:

final AtomicInteger counter = new AtomicInteger();
final int partitionSize=3;
final List<Object> list=new ArrayList<>();
final Collection<List<Object>>
                (it->counter.getAndIncrement() / partitionSize))

Input: [A, B, C, D, E]

Output: [[A, B, C], [D, E]]

You can find examples here:

How can I create directory tree in C++/Linux?

Easy with Boost.Filesystem: create_directories

#include <boost/filesystem.hpp>

Returns: true if a new directory was created, otherwise false.

Position absolute but relative to parent

#father {
   position: relative;

#son1 {
   position: absolute;
   top: 0;

#son2 {
   position: absolute;
   bottom: 0;

This works because position: absolute means something like "use top, right, bottom, left to position yourself in relation to the nearest ancestor who has position: absolute or position: relative."

So we make #father have position: relative, and the children have position: absolute, then use top and bottom to position the children.

Return background color of selected cell

If you are looking at a Table, a Pivot Table, or something with conditional formatting, you can try:


This also seems to work just fine on regular cells.

How can I color Python logging output?

I have two submissions to add, one of which colorizes just the message (ColoredFormatter), and one of which colorizes the entire line (ColorizingStreamHandler). These also include more ANSI color codes than previous solutions.

Some content has been sourced (with modification) from: The post above, and

Colorizes the message only:

class ColoredFormatter(logging.Formatter):
    """Special custom formatter for colorizing log messages!"""

    BLACK = '\033[0;30m'
    RED = '\033[0;31m'
    GREEN = '\033[0;32m'
    BROWN = '\033[0;33m'
    BLUE = '\033[0;34m'
    PURPLE = '\033[0;35m'
    CYAN = '\033[0;36m'
    GREY = '\033[0;37m'

    DARK_GREY = '\033[1;30m'
    LIGHT_RED = '\033[1;31m'
    LIGHT_GREEN = '\033[1;32m'
    YELLOW = '\033[1;33m'
    LIGHT_BLUE = '\033[1;34m'
    LIGHT_PURPLE = '\033[1;35m'
    LIGHT_CYAN = '\033[1;36m'
    WHITE = '\033[1;37m'

    RESET = "\033[0m"

    def __init__(self, *args, **kwargs):
        self._colors = {logging.DEBUG: self.DARK_GREY,
                        logging.INFO: self.RESET,
                        logging.WARNING: self.BROWN,
                        logging.ERROR: self.RED,
                        logging.CRITICAL: self.LIGHT_RED}
        super(ColoredFormatter, self).__init__(*args, **kwargs)

    def format(self, record):
        """Applies the color formats"""
        record.msg = self._colors[record.levelno] + record.msg + self.RESET
        return logging.Formatter.format(self, record)

    def setLevelColor(self, logging_level, escaped_ansi_code):
        self._colors[logging_level] = escaped_ansi_code

Colorizes the whole line:

class ColorizingStreamHandler(logging.StreamHandler):

    BLACK = '\033[0;30m'
    RED = '\033[0;31m'
    GREEN = '\033[0;32m'
    BROWN = '\033[0;33m'
    BLUE = '\033[0;34m'
    PURPLE = '\033[0;35m'
    CYAN = '\033[0;36m'
    GREY = '\033[0;37m'

    DARK_GREY = '\033[1;30m'
    LIGHT_RED = '\033[1;31m'
    LIGHT_GREEN = '\033[1;32m'
    YELLOW = '\033[1;33m'
    LIGHT_BLUE = '\033[1;34m'
    LIGHT_PURPLE = '\033[1;35m'
    LIGHT_CYAN = '\033[1;36m'
    WHITE = '\033[1;37m'

    RESET = "\033[0m"

    def __init__(self, *args, **kwargs):
        self._colors = {logging.DEBUG: self.DARK_GREY,
                        logging.INFO: self.RESET,
                        logging.WARNING: self.BROWN,
                        logging.ERROR: self.RED,
                        logging.CRITICAL: self.LIGHT_RED}
        super(ColorizingStreamHandler, self).__init__(*args, **kwargs)

    def is_tty(self):
        isatty = getattr(, 'isatty', None)
        return isatty and isatty()

    def emit(self, record):
            message = self.format(record)
            stream =
            if not self.is_tty:
                message = self._colors[record.levelno] + message + self.RESET
            stream.write(getattr(self, 'terminator', '\n'))
        except (KeyboardInterrupt, SystemExit):

    def setLevelColor(self, logging_level, escaped_ansi_code):
        self._colors[logging_level] = escaped_ansi_code

How do I remove files saying "old mode 100755 new mode 100644" from unstaged changes in Git?

Setting core.filemode to false does work, but make sure the settings in ~/.gitconfig aren't being overridden by those in .git/config.

send mail to multiple receiver with HTML mailto

"There are no safe means of assigning multiple recipients to a single mailto: link via HTML. There are safe, non-HTML, ways of assigning multiple recipients from a mailto: link."

For a quick fix to your problem, change your ; to a comma , and eliminate the spaces between email addresses

<a href='mailto:[email protected],[email protected]'>Email Us</a>

regular expression for Indian mobile numbers


I don't know if there is a simple expression for this but I have created this REGEX that validates all possible Indian numbers that contains (0 or +) then (91 or 22 (since I needed it for Maharashtra and second thing is that India have too many STD codes)) or directly searches for numbers starting with 6,7,8,9 that have/don't have a 0 in front of it .

(/[regex]/gm) is a trial for multi-line search you can remove it(//gm) if it fails to work/gives error.

Feel free to try it at regex101. My Project of this REGEX is here .

SVN 405 Method Not Allowed

I encountered the same issue and was able to fix it by:

  1. Copy the folder to another place.
  2. Delete .svn from copied folder
  3. Right click the original folder and select 'SVN Checkout'
  4. If you can't find (3), then your case is different than mine.
  5. See if the directory on the REPO-BROWSER is correct. For my case, this was the cause.
  6. Check out
  7. Get back the files from the copied folder into the original directory.
  8. Commit.

Failed to load resource: the server responded with a status of 500 (Internal Server Error) in Bind function

The 500 code would normally indicate an error on the server, not anything with your code. Some thoughts

  • Talk to the server developer for more info. You can't get more info directly.
  • Verify your arguments into the call (values). Look for anything you might think could cause a problem for the server process. The process should not die and should return you a better code, but bugs happen there also.
  • Could be intermittent, like if the server database goes down. May be worth trying at another time.