Programs & Examples On #Complete

How to take complete backup of mysql database using mysqldump command line utility

Use '-R' to backup stored procedures, but also keep in mind that if you want a consistent dump of your database while its being modified you need to use --single-transaction (if you only backup innodb) or --lock-all-tables (if you also need myisam tables)

{"<user xmlns=''> was not expected.} Deserializing Twitter XML

XmlSerializer xs = new XmlSerializer(typeof(User), new XmlRootAttribute("yourRootName")); 

Getting the client's time zone (and offset) in JavaScript

This will do the job.

var time = new Date(),
timestamp = Date(1000 + time.getTime());

Thu May 25 2017 21:35:14 GMT+0300 (IDT)


How to create checkbox inside dropdown?

Very simple code with Bootstrap and JQuery without any additionnal javascript code :


<div class="dropdown">
  <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    Dropdown button
  <form class="dropdown-menu" aria-labelledby="dropdownMenuButton">
    <label class="dropdown-item"><input type="checkbox" name="" value="one">First checkbox</label>
    <label class="dropdown-item"><input type="checkbox" name="" value="two">Second checkbox</label>
    <label class="dropdown-item"><input type="checkbox" name="" value="three">Third checkbox</label>


.dropdown-menu label {
  display: block;

Passing ArrayList through Intent

    public class StructMain implements Serializable {
    public  int id;
    public String name;
    public String lastName;

this my item . implement Serializable and create ArrayList

ArrayList<StructMain> items =new ArrayList<>();

and put in Bundle

Bundle bundle=new Bundle();

and create a new Intent that put Bundle to Intent

Intent intent=new Intent(ActivityOne.this,ActivityTwo.class);

for receive bundle insert this code

Bundle bundle = getIntent().getExtras();
ArrayList<StructMain> item = (ArrayList<StructMain>) bundle.getSerializable("test");

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

<body topmargin="0" leftmargin="0" rightmargin="0">

I'm not sure where you read this, but this is the accepted way of setting CSS styles inline is:

<body style="margin-top: 0px; margin-left: 0px; margin-right: 0px;">

And with a stylesheet:

  margin-top: 0px;
  margin-left: 0px;
  margin-right: 0px;

Convert HTML Character Back to Text Using Java Standard Library

As @jem suggested, it is possible to use jsoup.

With jSoup 1.8.3 it il possible to use the method Parser.unescapeEntities that retain the original html.

import org.jsoup.parser.Parser;
String html = Parser.unescapeEntities(original_html, false);

It seems that in some previous release this method is not present.

C# Select elements in list as List of string

List<string> empnames = (from e in emplist select e.Enaame).ToList();


string[] empnames = (from e in emplist select e.Enaame).ToArray();


How to get the changes on a branch in Git

git cherry branch [newbranch]

does exactly what you are asking, when you are in the master branch.

I am also very fond of:

git diff --name-status branch [newbranch]

Which isn't exactly what you're asking, but is still very useful in the same context.

Call an angular function inside html

Yep, just add parenthesis (calling the function). Make sure the function is in scope and actually returns something.

<ul class="ui-listview ui-radiobutton" ng-repeat="meter in meters">
  <li class = "ui-divider">
    {{ meter.DESCRIPTION }}
    {{ htmlgeneration() }}

Including jars in classpath on commandline (javac or apt)

Try the following:

java -cp jar1:jar2:jar3:dir1:. HelloWorld

The default classpath (unless there is a CLASSPATH environment variable) is the current directory so if you redefine it, make sure you're adding the current directory (.) to the classpath as I have done.

How to insert data to MySQL having auto incremented primary key?

Set the auto increment field to NULL or 0 if you want it to be auto magically assigned...

Insert multiple values using INSERT INTO (SQL Server 2005)

You can also use the following syntax:-

INSERT INTO MyTable (FirstCol, SecondCol)
SELECT 'First' ,1
SELECT 'Second' ,2
SELECT 'Third' ,3
SELECT 'Fourth' ,4
SELECT 'Fifth' ,5

From here

How to increase space between dotted border dots

This uses the standard CSS border and a pseudo element+overflow:hidden. In the example you get three different 2px dashed borders: normal, spaced like a 5px, spaced like a 10px. Is actually 10px with only 10-8=2px visible.

div.two{border:2px dashed #FF0000}_x000D_
div.five:before {_x000D_
  content: "";_x000D_
  position: absolute;_x000D_
  border: 5px dashed #FF0000;_x000D_
  top: -3px;_x000D_
  bottom: -3px;_x000D_
  left: -3px;_x000D_
  right: -3px;_x000D_
div.ten:before {_x000D_
  content: "";_x000D_
  position: absolute;_x000D_
  border: 10px dashed #FF0000;_x000D_
  top: -8px;_x000D_
  bottom: -8px;_x000D_
  left: -8px;_x000D_
  right: -8px;_x000D_
div.odd:before {left:0;right:0;border-radius:60px}_x000D_
div {_x000D_
  overflow: hidden;_x000D_
  position: relative;_x000D_
<div class="two">Kupo nuts here</div>_x000D_
<div class="five">Kupo nuts<br/>here</div>_x000D_
<div class="ten">Kupo<br/>nuts<br/>here</div>_x000D_
<div class="ten odd">Kupo<br/>nuts<br/>here</div>

Applied to small elements with big rounded corners may make for some fun effects.

Dart/Flutter : Converting timestamp

I tested this one and it works

// Map from firestore
// Using flutterfire package hence the returned data()
Map<String, dynamic> data =;
DateTime _timestamp = data['timestamp'].toDate();

Test details can be found here:

Regex Last occurrence?

If you don't want to include the backslash, but only the text after it, try this: ([^\\]+)$ or for unix: ([^\/]+)$

How to get current time with jQuery

<p id="date"></p>_x000D_
var d = new Date();_x000D_
document.getElementById("date").innerHTML = d.toTimeString();_x000D_

You can use Date() in JS.

Cast object to T

First check to see if it can be cast.

if (readData is T) {
    return (T)readData;
try {
   return (T)Convert.ChangeType(readData, typeof(T));
catch (InvalidCastException) {
   return default(T);

How to use glOrtho() in OpenGL?

Minimal runnable example

glOrtho: 2D games, objects close and far appear the same size:

enter image description here

glFrustrum: more real-life like 3D, identical objects further away appear smaller:

enter image description here


#include <stdlib.h>

#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>

static int ortho = 0;

static void display(void) {
    if (ortho) {
    } else {
        /* This only rotates and translates the world around to look like the camera moved. */
        gluLookAt(0.0, 0.0, -3.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    glColor3f(1.0f, 1.0f, 1.0f);

static void reshape(int w, int h) {
    glViewport(0, 0, w, h);
    if (ortho) {
        glOrtho(-2.0, 2.0, -2.0, 2.0, -1.5, 1.5);
    } else {
        glFrustum(-1.0, 1.0, -1.0, 1.0, 1.5, 20.0);

int main(int argc, char** argv) {
    glutInit(&argc, argv);
    if (argc > 1) {
        ortho = 1;
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(500, 500);
    glutInitWindowPosition(100, 100);
    glClearColor(0.0, 0.0, 0.0, 0.0);
    return EXIT_SUCCESS;

GitHub upstream.


gcc -ggdb3 -O0 -o main -std=c99 -Wall -Wextra -pedantic main.c -lGL -lGLU -lglut

Run with glOrtho:

./main 1

Run with glFrustrum:


Tested on Ubuntu 18.10.


Ortho: camera is a plane, visible volume a rectangle:

enter image description here

Frustrum: camera is a point,visible volume a slice of a pyramid:

enter image description here

Image source.


We are always looking from +z to -z with +y upwards:

glOrtho(left, right, bottom, top, near, far)
  • left: minimum x we see
  • right: maximum x we see
  • bottom: minimum y we see
  • top: maximum y we see
  • -near: minimum z we see. Yes, this is -1 times near. So a negative input means positive z.
  • -far: maximum z we see. Also negative.


Image source.

How it works under the hood

In the end, OpenGL always "uses":

glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0);

If we use neither glOrtho nor glFrustrum, that is what we get.

glOrtho and glFrustrum are just linear transformations (AKA matrix multiplication) such that:

  • glOrtho: takes a given 3D rectangle into the default cube
  • glFrustrum: takes a given pyramid section into the default cube

This transformation is then applied to all vertexes. This is what I mean in 2D:

Image source.

The final step after transformation is simple:

  • remove any points outside of the cube (culling): just ensure that x, y and z are in [-1, +1]
  • ignore the z component and take only x and y, which now can be put into a 2D screen

With glOrtho, z is ignored, so you might as well always use 0.

One reason you might want to use z != 0 is to make sprites hide the background with the depth buffer.


glOrtho is deprecated as of OpenGL 4.5: the compatibility profile 12.1. "FIXED-FUNCTION VERTEX TRANSFORMATIONS" is in red.

So don't use it for production. In any case, understanding it is a good way to get some OpenGL insight.

Modern OpenGL 4 programs calculate the transformation matrix (which is small) on the CPU, and then give the matrix and all points to be transformed to OpenGL, which can do the thousands of matrix multiplications for different points really fast in parallel.

Manually written vertex shaders then do the multiplication explicitly, usually with the convenient vector data types of the OpenGL Shading Language.

Since you write the shader explicitly, this allows you to tweak the algorithm to your needs. Such flexibility is a major feature of more modern GPUs, which unlike the old ones that did a fixed algorithm with some input parameters, can now do arbitrary computations. See also:

With an explicit GLfloat transform[] it would look something like this:


#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#include <GL/glew.h>

#include <GLFW/glfw3.h>

static const GLuint WIDTH = 800;
static const GLuint HEIGHT = 600;
/* ourColor is passed on to the fragment shader. */
static const GLchar* vertex_shader_source =
    "#version 330 core\n"
    "layout (location = 0) in vec3 position;\n"
    "layout (location = 1) in vec3 color;\n"
    "out vec3 ourColor;\n"
    "uniform mat4 transform;\n"
    "void main() {\n"
    "    gl_Position = transform * vec4(position, 1.0f);\n"
    "    ourColor = color;\n"
static const GLchar* fragment_shader_source =
    "#version 330 core\n"
    "in vec3 ourColor;\n"
    "out vec4 color;\n"
    "void main() {\n"
    "    color = vec4(ourColor, 1.0f);\n"
static GLfloat vertices[] = {
/*   Positions          Colors */
     0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f,
    -0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f,
     0.0f,  0.5f, 0.0f, 0.0f, 0.0f, 1.0f

/* Build and compile shader program, return its ID. */
GLuint common_get_shader_program(
    const char *vertex_shader_source,
    const char *fragment_shader_source
) {
    GLchar *log = NULL;
    GLint log_length, success;
    GLuint fragment_shader, program, vertex_shader;

    /* Vertex shader */
    vertex_shader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertex_shader, 1, &vertex_shader_source, NULL);
    glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &success);
    glGetShaderiv(vertex_shader, GL_INFO_LOG_LENGTH, &log_length);
    log = malloc(log_length);
    if (log_length > 0) {
        glGetShaderInfoLog(vertex_shader, log_length, NULL, log);
        printf("vertex shader log:\n\n%s\n", log);
    if (!success) {
        printf("vertex shader compile error\n");

    /* Fragment shader */
    fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragment_shader, 1, &fragment_shader_source, NULL);
    glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &success);
    glGetShaderiv(fragment_shader, GL_INFO_LOG_LENGTH, &log_length);
    if (log_length > 0) {
        log = realloc(log, log_length);
        glGetShaderInfoLog(fragment_shader, log_length, NULL, log);
        printf("fragment shader log:\n\n%s\n", log);
    if (!success) {
        printf("fragment shader compile error\n");

    /* Link shaders */
    program = glCreateProgram();
    glAttachShader(program, vertex_shader);
    glAttachShader(program, fragment_shader);
    glGetProgramiv(program, GL_LINK_STATUS, &success);
    glGetProgramiv(program, GL_INFO_LOG_LENGTH, &log_length);
    if (log_length > 0) {
        log = realloc(log, log_length);
        glGetProgramInfoLog(program, log_length, NULL, log);
        printf("shader link log:\n\n%s\n", log);
    if (!success) {
        printf("shader link error");

    /* Cleanup. */
    return program;

int main(void) {
    GLint shader_program;
    GLint transform_location;
    GLuint vbo;
    GLuint vao;
    GLFWwindow* window;
    double time;

    window = glfwCreateWindow(WIDTH, HEIGHT, __FILE__, NULL, NULL);
    glewExperimental = GL_TRUE;
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glViewport(0, 0, WIDTH, HEIGHT);

    shader_program = common_get_shader_program(vertex_shader_source, fragment_shader_source);

    glGenVertexArrays(1, &vao);
    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    /* Position attribute */
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)0);
    /* Color attribute */
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));

    while (!glfwWindowShouldClose(window)) {

        transform_location = glGetUniformLocation(shader_program, "transform");
        /* THIS is just a dummy transform. */
        GLfloat transform[] = {
            0.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 1.0f, 0.0f,
            0.0f, 0.0f, 0.0f, 1.0f,
        time = glfwGetTime();
        transform[0] = 2.0f * sin(time);
        transform[5] = 2.0f * cos(time);
        glUniformMatrix4fv(transform_location, 1, GL_FALSE, transform);

        glDrawArrays(GL_TRIANGLES, 0, 3);
    glDeleteVertexArrays(1, &vao);
    glDeleteBuffers(1, &vbo);
    return EXIT_SUCCESS;

GitHub upstream.

Compile and run:

gcc -ggdb3 -O0 -o glfw_transform.out -std=c99 -Wall -Wextra -pedantic glfw_transform.c -lGL -lGLU -lglut -lGLEW -lglfw -lm


enter image description here

The matrix for glOrtho is really simple, composed only of scaling and translation:

scalex, 0,      0,      translatex,
0,      scaley, 0,      translatey,
0,      0,      scalez, translatez,
0,      0,      0,      1

as mentioned in the OpenGL 2 docs.

The glFrustum matrix is not too hard to calculate by hand either, but starts getting annoying. Note how frustum cannot be made up with only scaling and translations like glOrtho, more info at:

The GLM OpenGL C++ math library is a popular choice for calculating such matrices. documents both an ortho and frustum operations.

Convert int to char in java

First, convert the int (or another type) to String,

int a = 1;
String value = String.valueOf(a);

Then, convert that String to char.

char newValue = value.charAt(0);

You can avoid empty output in this way...


How do I make an editable DIV look like a text field?

These look the same as their real counterparts in Safari, Chrome, and Firefox. They degrade gracefully and look OK in Opera and IE9, too.



textarea {
    height: 28px;
    width: 400px;

#textarea {
    -moz-appearance: textfield-multiline;
    -webkit-appearance: textarea;
    border: 1px solid gray;
    font: medium -moz-fixed;
    font: -webkit-small-control;
    height: 28px;
    overflow: auto;
    padding: 2px;
    resize: both;
    width: 400px;

input {
    margin-top: 5px;
    width: 400px;

#input {
    -moz-appearance: textfield;
    -webkit-appearance: textfield;
    background-color: white;
    background-color: -moz-field;
    border: 1px solid darkgray;
    box-shadow: 1px 1px 1px 0 lightgray inset;  
    font: -moz-field;
    font: -webkit-small-control;
    margin-top: 5px;
    padding: 2px 3px;
    width: 398px;    


<textarea>I am a textarea</textarea>
<div id="textarea" contenteditable>I look like textarea</div>

<input value="I am an input" />
<div id="input" contenteditable>I look like an input</div>


enter image description here

finding multiples of a number in Python

Does this do what you want?

print range(0, (m+1)*n, n)[1:]

For m=5, n=20

[20, 40, 60, 80, 100]

Or better yet,

>>> print range(n, (m+1)*n, n)
[20, 40, 60, 80, 100] 

For Python3+

>>> print(list(range(n, (m+1)*n, n)))
[20, 40, 60, 80, 100] 

Using Composer's Autoload

In my opinion, Sergiy's answer should be the selected answer for the given question. I'm sharing my understanding.

I was looking to autoload my package files using composer which I have under the dir structure given below.

    |           |--------App/
    |           |
    |           |--------Test/
    |           |
    |           |---------composer/
    |           |           |---------autoload_psr4.php
    |           |           
    |           |----------autoload.php

I'm using psr-4 autoloading specification.

Had to add below lines to the project's composer.json. I intend to place my class files inside src/App , src/Test and library directory.

"autoload": {
        "psr-4": {
            "OrgName\\AppType\\AppName\\": ["src/App", "src/Test", "library/"]

This is pretty much self explaining. OrgName\AppType\AppName is my intended namespace prefix. e.g for class User in src/App/Controller/Provider/User.php -

namespace OrgName\AppType\AppName\Controller\Provider; // namespace declaration

use OrgName\AppType\AppName\Controller\Provider\User; // when using the class

Also notice "src/App", "src/Test" .. are from your web-root that is where your composer.json is. Nothing to do with the vendor dir. take a look at vendor/autoload.php

Now if composer is installed properly all that is required is #composer update

After composer update my classes loaded successfully. What I observed is that composer is adding a line in vendor/composer/autoload_psr4.php

$vendorDir = dirname(dirname(__FILE__));
$baseDir = dirname($vendorDir);

return array(
    'Monolog\\' => array($vendorDir . '/monolog/monolog/src/Monolog'),
    'OrgName\\AppType\\AppName\\' => array($baseDir . '/src/App', $baseDir . '/src/Test', $baseDir . '/library'),

This is how composer maps. For psr-0 mapping is in vendor/composer/autoload_classmap.php

How to iterate through SparseArray?

For removing all the elements from SparseArray using the above looping leads to Exception.

To avoid this Follow the below code to remove all the elements from SparseArray using normal loops

private void getValues(){      
    for(int i=0; i<sparseArray.size(); i++){
          int key = sparseArray.keyAt(i);
          Log.d("Element at "+key, " is "+sparseArray.get(key));

Cloning a private Github repo

This worked for me on mac git clone https://[email protected]:username/repo_name

How to fix nginx throws 400 bad request headers on any header testing tools?

As stated by Maxim Dounin in the comments above:

When nginx returns 400 (Bad Request) it will log the reason into error log, at "info" level. Hence an obvious way to find out what's going on is to configure error_log to log messages at "info" level and take a look into error log when testing.

gcc-arm-linux-gnueabi command not found

I had to cross compile C code in Ubuntu for ARM. This worked for me:

$ sudo apt install gcc-arm-none-eabi

Later, tested it on the qemu emulator

#Install qemu
sudo apt-get install qemu qemu-user-static qemu-system-arm

#Cross compile "helloworld.c"
$ arm-none-eabi-gcc --specs=rdimon.specs   -Wl,--start-group -lgcc -lc -lm -lrdimon -Wl,--end-group helloworld.c -o helloworld

qemu-arm-static helloworld

How to Find App Pool Recycles in Event Log

IIS version 8.5 +

To enable Event Tracing for Windows for your website/application

  1. Go to Logging and ensure either ETW event only or Both log file and ETW event selected.

enter image description here

  1. Enable the desired Recycle logs in the Advanced Settings for the Application Pool:

enter image description here

  1. Go to the default Custom View: WebServer filters IIS logs:

Custom Views > ServerRoles > Web Server

enter image description here

  1. ... or System logs:

Windows Logs > System

proper way to logout from a session in PHP

From the session_destroy() page in the PHP manual:

// Initialize the session.
// If you are using session_name("something"), don't forget it now!

// Unset all of the session variables.
$_SESSION = array();

// If it's desired to kill the session, also delete the session cookie.
// Note: This will destroy the session, and not just the session data!
if (ini_get("session.use_cookies")) {
    $params = session_get_cookie_params();
    setcookie(session_name(), '', time() - 42000,
        $params["path"], $params["domain"],
        $params["secure"], $params["httponly"]

// Finally, destroy the session.

In c, in bool, true == 1 and false == 0?

More accurately anything that is not 0 is true.

So 1 is true, but so is 2, 3 ... etc.

How to run SQL in shell script



           select count(*) from table;


PL_CONNECT_STRING carry database username, password and it service name

sqlplus is used to connect the Database with PL_CONNECT_STRING details

END-OF-SQL tag contain the query which you want to execute

echo is used to print the output of the query

NOTE: You can give multiple Query inside the END-OF-SQL tag, so its useful for batch execution as well

java - path to trustStore - set property doesn't work?

You have a typo - it is trustStore.

Apart from setting the variables with System.setProperty(..), you can also use

SQL Update to the SUM of its joined values

With postgres, I had to adjust the solution with this to work for me:

UPDATE BookingPitches AS p
SET extrasPrice = t.sumPrice
        SELECT PitchID, SUM(Price) sumPrice
        FROM BookingPitchExtras
        WHERE [required] = 1
        GROUP BY PitchID 
    ) t
WHERE t.PitchID = p.ID AND p.bookingID = 1

How to get the width of a react element

With hooks:

const MyComponent = () => {
  const ref = useRef(null);
  useEffect(() => {
    console.log('width', ref.current ? ref.current.offsetWidth : 0);
  }, [ref.current]);
  return <div ref={ref}>Hello</div>;

How are parameters sent in an HTTP POST request?

The values are sent in the request body, in the format that the content type specifies.

Usually the content type is application/x-www-form-urlencoded, so the request body uses the same format as the query string:


When you use a file upload in the form, you use the multipart/form-data encoding instead, which has a different format. It's more complicated, but you usually don't need to care what it looks like, so I won't show an example, but it can be good to know that it exists.

How to "log in" to a website using Python's Requests module?

If the information you want is on the page you are directed to immediately after login...

Lets call your ck variable payload instead, like in the python-requests docs:

payload = {'inUserName': 'USERNAME/EMAIL', 'inUserPass': 'PASSWORD'}
url = '', data=payload)


See below.

How to create a custom navigation drawer in android

I used below layout and able to achieve custom layout in Navigation View.



            <include layout="@layout/drawer_header" />

            <include layout="@layout/navigation_drawer_menu" />

How do I get the last character of a string?

public char LastChar(String a){
    return a.charAt(a.length() - 1);

Fix footer to bottom of page

A very simple example that shows how to fix the footer at the bottom in your application's layout.

/* Styles go here */_x000D_
html{ height: 100%;}_x000D_
body{ min-height: 100%; background: #fff;}_x000D_
.page-layout{ border: none; width: 100%; height: 100vh; }_x000D_
.page-layout td{ vertical-align: top; }_x000D_
.page-layout .header{ background: #aaa; }_x000D_
.page-layout .main-content{ height: 100%; background: #f1f1f1; text-align: center; padding-top: 50px; }_x000D_
.page-layout .main-content .container{ text-align: center; padding-top: 50px; }_x000D_
.page-layout .footer{ background: #333; color: #fff; } 
<!DOCTYPE html>_x000D_
    <link data-require="bootstrap@*" data-semver="4.0.5" rel="stylesheet" href="" />_x000D_
    <link rel="stylesheet" href="style.css" />_x000D_
    <script src="script.js"></script>_x000D_
    <table class="page-layout">_x000D_
        <td class="header">_x000D_
            This is the site header._x000D_
        <td class="main-content">_x000D_
            <h1>Fix footer always to the bottom</h1>_x000D_
              This is how you can simply fix the footer to the bottom._x000D_
              The footer will always stick to the bottom until the main-content doesn't grow till footer._x000D_
              Even if the content grows, the footer will start to move down naturally as like the normal behavior of page._x000D_
        <td class="footer">_x000D_
            This is the site footer._x000D_

Add views below toolbar in CoordinatorLayout

As of Android studio 3.4, You need to put this line in your Layout which holds the RecyclerView.


How to unpack pkl file?


Your pkl file is, in fact, a serialized pickle file, which means it has been dumped using Python's pickle module.

To un-pickle the data you can:

import pickle

with open('serialized.pkl', 'rb') as f:
    data = pickle.load(f)

For the MNIST data set

Note gzip is only needed if the file is compressed:

import gzip
import pickle

with'mnist.pkl.gz', 'rb') as f:
    train_set, valid_set, test_set = pickle.load(f)

Where each set can be further divided (i.e. for the training set):

train_x, train_y = train_set

Those would be the inputs (digits) and outputs (labels) of your sets.

If you want to display the digits:

import as cm
import matplotlib.pyplot as plt

plt.imshow(train_x[0].reshape((28, 28)), cmap=cm.Greys_r)


The other alternative would be to look at the original data:

But that will be harder, as you'll need to create a program to read the binary data in those files. So I recommend you to use Python, and load the data with pickle. As you've seen, it's very easy. ;-)

Escaping single quotes in JavaScript string for JavaScript evaluation

I agree that this var formattedString = string.replace(/'/g, "\\'"); works very well, but since I used this part of code in PHP with the framework Prado (you can register the js script in a PHP class) I needed this sample working inside double quotes.

The solution that worked for me is that you need to put three \ and escape the double quotes. "var string = \"l'avancement\"; var formattedString = string.replace(/'/g, \"\\\'\");"

I answer that question since I had trouble finding that three \ was the work around.

Storing Objects in HTML5 localStorage

I made a thing that doesn't break the existing Storage objects, but creates a wrapper so you can do what you want. The result is a normal object, no methods, with access like any object.

The thing I made.

If you want 1 localStorage property to be magic:

var prop = ObjectStorage(localStorage, 'prop');

If you need several:

var storage = ObjectStorage(localStorage, ['prop', 'more', 'props']);

Everything you do to prop, or the objects inside storage will be automatically saved into localStorage. You're always playing with a real object, so you can do stuff like this:'more data');
storage.another.list.splice(1, 2, {another: 'object'});

And every new object inside a tracked object will be automatically tracked.

The very big downside: it depends on Object.observe() so it has very limited browser support. And it doesn't look like it'll be coming for Firefox or Edge anytime soon.

how to compare two string dates in javascript?

You can simply compare 2 strings

function isLater(dateString1, dateString2) {
  return dateString1 > dateString2


isLater("2012-12-01", "2012-11-01")

returns true while

isLater("2012-12-01", "2013-11-01")

returns false

Objective-C for Windows

If you just want to experiment, there's an Objective-C compiler for .NET (Windows) here: qckapp

JavaScript backslash (\) in variables is causing an error

The backslash \ is reserved for use as an escape character in Javascript.

To use a backslash literally you need to use two backslashes


How do I style (css) radio buttons and labels?

This will get your buttons and labels next to each other, at least. I believe the second part can't be done in css alone, and will need javascript. I found a page that might help you with that part as well, but I don't have time right now to try it out:

<style type="text/css">
.input input {
  float: left;
.input label {
  margin: 5px;
<div class="input radio">
        <legend>What color is the sky?</legend>
        <input type="hidden" name="data[Submit][question]" value="" id="SubmitQuestion" />

        <input type="radio" name="data[Submit][question]" id="SubmitQuestion1" value="1"  />
        <label for="SubmitQuestion1">A strange radient green.</label>

        <input type="radio" name="data[Submit][question]" id="SubmitQuestion2" value="2"  />
        <label for="SubmitQuestion2">A dark gloomy orange</label>
        <input type="radio" name="data[Submit][question]" id="SubmitQuestion3" value="3"  />
        <label for="SubmitQuestion3">A perfect glittering blue</label>

Android check permission for LocationManager

Use my custome class to check or request permisson

public class Permissons {

        //Request Permisson
        public static void Request_STORAGE(Activity act,int code)

            ActivityCompat.requestPermissions(act, new
        public static void Request_CAMERA(Activity act,int code)
            ActivityCompat.requestPermissions(act, new
        public static void Request_FINE_LOCATION(Activity act,int code)
            ActivityCompat.requestPermissions(act, new
        public static void Request_READ_SMS(Activity act,int code)
            ActivityCompat.requestPermissions(act, new
        public static void Request_READ_CONTACTS(Activity act,int code)
            ActivityCompat.requestPermissions(act, new
        public static void Request_READ_CALENDAR(Activity act,int code)
            ActivityCompat.requestPermissions(act, new
        public static void Request_RECORD_AUDIO(Activity act,int code)
            ActivityCompat.requestPermissions(act, new

        //Check Permisson
        public static boolean Check_STORAGE(Activity act)
            int result = ContextCompat.checkSelfPermission(act,android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
            return result == PackageManager.PERMISSION_GRANTED;
        public static boolean Check_CAMERA(Activity act)
            int result = ContextCompat.checkSelfPermission(act, Manifest.permission.CAMERA);
            return result == PackageManager.PERMISSION_GRANTED;
        public static boolean Check_FINE_LOCATION(Activity act)
            int result = ContextCompat.checkSelfPermission(act, Manifest.permission.ACCESS_FINE_LOCATION);
            return result == PackageManager.PERMISSION_GRANTED;
        public static boolean Check_READ_SMS(Activity act)
            int result = ContextCompat.checkSelfPermission(act, Manifest.permission.READ_SMS);
            return result == PackageManager.PERMISSION_GRANTED;
        public static boolean Check_READ_CONTACTS(Activity act)
            int result = ContextCompat.checkSelfPermission(act, Manifest.permission.READ_CONTACTS);
            return result == PackageManager.PERMISSION_GRANTED;
        public static boolean Check_READ_CALENDAR(Activity act)
            int result = ContextCompat.checkSelfPermission(act, Manifest.permission.READ_CALENDAR);
            return result == PackageManager.PERMISSION_GRANTED;
        public static boolean Check_RECORD_AUDIO(Activity act)
            int result = ContextCompat.checkSelfPermission(act, Manifest.permission.RECORD_AUDIO);
            return result == PackageManager.PERMISSION_GRANTED;


   //if not permisson granted so request permisson with request code

How to negate 'isblank' function

The solution is isblank(cell)=false

TypeError: list indices must be integers or slices, not str

I had same error and the mistake was that I had added list and dictionary into the same list (object) and when I used to iterate over the list of dictionaries and use to hit a list (type) object then I used to get this error.

Its was a code error and made sure that I only added dictionary objects to that list and list typed object into the list, this solved my issue as well.

HTML set image on browser tab

It's called a Favicon, have a read.

<link rel="shortcut icon" href=""/>

You can use this neat tool to generate cross-browser compatible Favicons.

How to launch an application from a browser?

You can't really "launch an application" in the true sense. You can as you indicated ask the user to open a document (ie a PDF) and windows will attempt to use the default app for that file type. Many applications have a way to do this.

For example you can save RDP connections as a .rdp file. Putting a link on your site to something like this should allow the user to launch right into an RDP session:

<a href="MyServer1.rdp">Server 1</a>

Skipping error in for-loop

Instead of catching the error, wouldn't it be possible to test in or before the myplotfunction() function first if the error will occur (i.e. if the breaks are unique) and only plot it for those cases where it won't appear?!

Ajax - 500 Internal Server Error

One must use behavior: JsonRequestBehavior.AllowGet in Post Json Return in C#

jquery - Check for file extension before uploading

I would like to thank the person who posted the answer, but he has deleted the post. We can do it like this.

   'uploader': ...,
   'script': ...
    'fileExt' : '*.jpg;*.gif;', //add allowed extensions
    'onSelect': function(e, q, f) {
        var validExtensions = ['jpg','gif']; //array of valid extensions
        var fileName =;
        var fileNameExt = fileName.substr(fileName.lastIndexOf('.') + 1);
        if ($.inArray(fileNameExt, validExtensions) == -1){
           alert("Invalid file type");
           return false;

Thanks for the answer, it really worked...

Creating a Custom Event

Based on @ionden's answer, the call to the delegate could be simplified using null propagation since C# 6.0.

Your code would simply be:

class MyClass {
    public event EventHandler MyEvent;

    public void Method() {
        MyEvent?.Invoke(this, EventArgs.Empty);

Use it like this:

MyClass myObject = new MyClass();
myObject.MyEvent += new EventHandler(myObject_MyEvent);

Why is "forEach not a function" for this object?

If you really need to use a secure foreach interface to iterate an object and make it reusable and clean with a npm module, then use this,


import each from 'foreach-object';
const object = {
   firstName: 'Arosha',
   lastName: 'Sum',
   country: 'Australia'
each(object, (value, key, object) => {
   console.log(key + ': ' + value);
// Console log output will be:
//      firstName: Arosha
//      lastName: Sum
//      country: Australia

What is the .idea folder?

It contains your local IntelliJ IDE configs. I recommend adding this folder to your .gitignore file:

# intellij configs

Bootstrap 3 collapsed menu doesn't close on click

Simple Try to make a function in javascript for dropdown collapse class.



$scope.toogleMyClass  = function(){


        $scope.preLoader = false;
        $(document).ready(function() {


Hook this function to onClick simple works for me.

ZIP file content type for HTTP request

If you want the MIME type for a file, you can use the following code:

- (NSString *)mimeTypeForPath:(NSString *)path
    // get a mime type for an extension using MobileCoreServices.framework

    CFStringRef extension = (__bridge CFStringRef)[path pathExtension];
    CFStringRef UTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, extension, NULL);
    assert(UTI != NULL);

    NSString *mimetype = CFBridgingRelease(UTTypeCopyPreferredTagWithClass(UTI, kUTTagClassMIMEType));
    assert(mimetype != NULL);


    return mimetype;

In the case of a ZIP file, this will return application/zip.

AttributeError: 'module' object has no attribute 'urlopen'

One of the possible way to do it:

import urllib

    # Python 2
    from urllib2 import urlopen
except ImportError:
    # Python 3
    from urllib.request import urlopen

What is difference between mutable and immutable String in java

What is difference between mutable and immutable String in java

immutable exist, mutable don't.

"The certificate chain was issued by an authority that is not trusted" when connecting DB in VM Role from Azure website

Got hit by the same issue while accessing SQLServer from IIS. Adding TrustServerCertificate=True didnot help.

Could see a comment in MS docs: Make sure the SQLServer service account has access to the TLS Certificate you are using. (NT Service\MSSQLSERVER)

Open personal store and right click on the certificate -> manage private keys -> Add the SQL service account and give full control.

Restart the SQL service. It worked.

Upgrade Node.js to the latest version on Mac OS

I use Node version manager (called n) for it.

npm install -g n


n latest


n stable

How to access List elements

Recursive solution to print all items in a list:

def printItems(l):
   for i in l:
      if isinstance(i,list):
         print i

l = [['vegas','London'],['US','UK']]

PostgreSQL database default location on Linux


At least in Gentoo Linux and Ubuntu 14.04 by default.

You can find postgresql.conf and look at param data_directory. If it is commented then database directory is the same as this config file directory.

Option to ignore case with .contains method?

With a null check on the dvdList and your searchString

    if (!StringUtils.isEmpty(searchString)) {
        return Optional.ofNullable(dvdList)
                       .anyMatch(dvd >searchString.equalsIgnoreCase(dvd.getTitle()));

Running Internet Explorer 6, Internet Explorer 7, and Internet Explorer 8 on the same machine

I did this on my Windows 7 computer today:

  1. Installed Windows Virtual PC, and ran XP Mode
  2. Created two Windows XP images. One with Internet Explorer 6 and one with Internet Explorer 7.
  3. Now I can run these to browsers from my Windows 7 desktop! Just like any other application. No need to open Virtual PC.

Programmatically add custom event in the iPhone Calendar

Swift 4.0 implementation :

use import in top of page by import EventKit


@IBAction func addtoCalendarClicked(sender: AnyObject) {

    let eventStore = EKEventStore()

    eventStore.requestAccess( to: EKEntityType.event, completion:{(granted, error) in

        if (granted) && (error == nil) {
            print("granted \(granted)")
            print("error \(error)")

            let event = EKEvent(eventStore: eventStore)

            event.title = "Event Title"
            event.startDate = Date()
            event.endDate = Date()
            event.notes = "Event Details Here"
            event.calendar = eventStore.defaultCalendarForNewEvents

            var event_id = ""
            do {
                try, span: .thisEvent)
                event_id = event.eventIdentifier
            catch let error as NSError {
                print("json error: \(error.localizedDescription)")

            if(event_id != ""){
                print("event added !")

MySQL: Curdate() vs Now()

CURDATE() will give current date while NOW() will give full date time.

Run the queries, and you will find out whats the difference between them.

SELECT NOW();     -- You will get 2010-12-09 17:10:18
SELECT CURDATE(); -- You will get 2010-12-09

Better way to check if a Path is a File or a Directory?

Maybe for UWP C#

public static async Task<IStorageItem> AsIStorageItemAsync(this string iStorageItemPath)
        if (string.IsNullOrEmpty(iStorageItemPath)) return null;
        IStorageItem storageItem = null;
            storageItem = await StorageFolder.GetFolderFromPathAsync(iStorageItemPath);
            if (storageItem != null) return storageItem;
        } catch { }
            storageItem = await StorageFile.GetFileFromPathAsync(iStorageItemPath);
            if (storageItem != null) return storageItem;
        } catch { }
        return storageItem;

In Jinja2, how do you test if a variable is undefined?

{% if variable is defined %} works to check if something is undefined.

You can get away with using {% if not var1 %} if you default your variables to False eg

class MainHandler(BaseHandler):
    def get(self):
        var1 = self.request.get('var1', False)

Print a div content using Jquery

None of the solutions above work perfectly.They either loses CSS or have to include/edit external CSS file. I found a perfect solution that will not lose your CSS nor you have to edit/add external CSS.


<div id='printarea'>
    <p>This is a sample text for printing purpose.</p>
    <input type='button' id='btn' value='Print' onclick='printFunc();'>
<p>Do not print.</p


function printFunc() {
    var divToPrint = document.getElementById('printarea');
    var htmlToPrint = '' +
        '<style type="text/css">' +
        'table th, table td {' +
        'border:1px solid #000;' +
        'padding;0.5em;' +
        '}' +
    htmlToPrint += divToPrint.outerHTML;
    newWin ="");
    newWin.document.write("<h3 align='center'>Print Page</h3>");

How often should you use git-gc?

You don't have to use git gc very often, because git gc (Garbage collection) is run automatically on several frequently used commands:

git pull
git merge
git rebase
git commit

Source: git gc best practices and FAQS

React: Expected an assignment or function call and instead saw an expression

Not sure about solutions but a temporary workaround is to ask eslint to ignore it by adding the following on top of the problem line.

// eslint-disable-next-line @typescript-eslint/no-unused-expressions

Find IP address of directly connected device

You can also get information from directly connected networking devices, such as network switches with LDWin, a portable and free Windows program published on github:

LDWin supports the following methods of link discovery: CDP (Cisco Discovery Protocol) and LLDP (Link Layer Discovery Protocol).

You can obtain the model, management IP, VLAN identifier, Port identifier, firmware version, etc.

Set LIMIT with doctrine 2?

$query_ids = $this->getEntityManager()
        FROM MuzichCoreBundle:Element e_
        WHERE [...]
        GROUP BY")

HERE in the second query the result of the first query should be passed ..

$query_select = "SELECT e
      FROM MuzichCoreBundle:Element e 
      WHERE IN (".$query_ids->getResult().")
      ORDER BY e.created DESC, DESC"

$query = $this->getEntityManager()

$resultCollection = $query->getResult();

What is the difference between Hibernate and Spring Data JPA

Spring Data is a convenience library on top of JPA that abstracts away many things and brings Spring magic (like it or not) to the persistence store access. It is primarily used for working with relational databases. In short, it allows you to declare interfaces that have methods like findByNameOrderByAge(String name); that will be parsed in runtime and converted into appropriate JPA queries.

Its placement atop of JPA makes its use tempting for:

  1. Rookie developers who don't know SQL or know it badly. This is a recipe for disaster but they can get away with it if the project is trivial.

  2. Experienced engineers who know what they do and want to spindle up things fast. This might be a viable strategy (but read further).

From my experience with Spring Data, its magic is too much (this is applicable to Spring in general). I started to use it heavily in one project and eventually hit several corner cases where I couldn't get the library out of my way and ended up with ugly workarounds. Later I read other users' complaints and realized that these issues are typical for Spring Data. For example, check this issue that led to hours of investigation/swearing:

 public TourAccommodationRate createTourAccommodationRate(
        @RequestBody TourAccommodationRate tourAccommodationRate
    ) {
        if (tourAccommodationRate.getId() != null) {
            throw new BadRequestException("id MUST NOT be specified in a body during entry creation");

        // This is an ugly hack required for the Room slim model to work. The problem stems from the fact that
        // when we send a child entity having the many-to-many (M:N) relation to the containing entity, its
        // information is not fetched. As a result, we get NPEs when trying to access all but its Id in the
        // code creating the corresponding slim model. By detaching the entity from the persistence context we
        // force the ORM to re-fetch it from the database instead of taking it from the cache;
        return tourAccommodationRateRepository.findOne(tourAccommodationRate.getId());

I ended up going lower level and started using JDBI - a nice library with just enough "magic" to save you from the boilerplate. With it, you have complete control over SQL queries and almost never have to fight the library.

Get a JSON object from a HTTP response

The string that you get is just the JSON Object.toString(). It means that you get the JSON object, but in a String format.

If you are supposed to get a JSON Object you can just put:

JSONObject myObject = new JSONObject(result);

jQuery UI: Datepicker set year range dropdown to 100 years

I wanted to implement the datepicker to select the birthdate and I had troubles changing the yearRange as it doesn't seemed to work with my version (1.5). I updated to the newest jquery-ui datepicker version here:

Then I found out they provide this very helpful on-the-fly tool, so you can config your whole datepicker and see what settings you have to use.

That's how I found out that the option


is the option I was looking for and I didn't find any results searching the web.

So for other users: If you also want to provide the datepicker to change the birthdate, I suggest to use this code options:

    startView: 2,
    maxViewMode: 2,
    daysOfWeekHighlighted: "1,2",
    defaultViewDate: { year: new Date().getFullYear()-20, month: 01, day: 01 }

When opening the datepicker you will start with the view to select the years, 20 years ago relative to the current year.

Assignment makes pointer from integer without cast

strToLower's return type should be char* not char (or it should return nothing at all, since it doesn't re-allocate the string)

JavaScript equivalent to printf/String.Format

I want to share my solution for the 'problem'. I haven't re-invented the wheel but tries to find a solution based on what JavaScript already does. The advantage is, that you get all implicit conversions for free. Setting the prototype property $ of String gives a very nice and compact syntax (see examples below). It is maybe not the most efficient way, but in most cases dealing with output it does not have to be super optimized.

String.form = function(str, arr) {
    var i = -1;
    function callback(exp, p0, p1, p2, p3, p4) {
        if (exp=='%%') return '%';
        if (arr[++i]===undefined) return undefined;
        exp  = p2 ? parseInt(p2.substr(1)) : undefined;
        var base = p3 ? parseInt(p3.substr(1)) : undefined;
        var val;
        switch (p4) {
            case 's': val = arr[i]; break;
            case 'c': val = arr[i][0]; break;
            case 'f': val = parseFloat(arr[i]).toFixed(exp); break;
            case 'p': val = parseFloat(arr[i]).toPrecision(exp); break;
            case 'e': val = parseFloat(arr[i]).toExponential(exp); break;
            case 'x': val = parseInt(arr[i]).toString(base?base:16); break;
            case 'd': val = parseFloat(parseInt(arr[i], base?base:10).toPrecision(exp)).toFixed(0); break;
        val = typeof(val)=='object' ? JSON.stringify(val) : val.toString(base);
        var sz = parseInt(p1); /* padding size */
        var ch = p1 && p1[0]=='0' ? '0' : ' '; /* isnull? */
        while (val.length<sz) val = p0 !== undefined ? val+ch : ch+val; /* isminus? */
       return val;
    var regex = /%(-)?(0?[0-9]+)?([.][0-9]+)?([#][0-9]+)?([scfpexd%])/g;
    return str.replace(regex, callback);

String.prototype.$ = function() {
    return String.form(this,;

Here are a few examples:

String.format("%s %s", [ "This is a string", 11 ])
console.log("%s %s".$("This is a string", 11))
var arr = [ "12.3", 13.6 ]; console.log("Array: %s".$(arr));
var obj = { test:"test", id:12 }; console.log("Object: %s".$(obj));
console.log("%c", "Test");
console.log("%5d".$(12)); // '   12'
console.log("%05d".$(12)); // '00012'
console.log("%-5d".$(12)); // '12   '
console.log("%5.2d".$(123)); // '  120'
console.log("%5.2f".$(1.1)); // ' 1.10'
console.log("%10.2e".$(1.1)); // '   1.10e+0'
console.log("%5.3p".$(1.12345)); // ' 1.12'
console.log("%5x".$(45054)); // ' affe'
console.log("%20#2x".$("45054")); // '    1010111111111110'
console.log("%6#2d".$("111")); // '     7'
console.log("%6#16d".$("affe")); // ' 45054'

What is the meaning of <> in mysql query?

In MySQL, I use <> to preferentially place specific rows at the front of a sort request.

For instance, under the column topic, I have the classifications of 'Chair', 'Metabolomics', 'Proteomics', and 'Endocrine'. I always want to list any individual(s) with the topic 'Chair', first, and then list the other members in alphabetical order based on their topic and then their name_last.

I do this with:

SELECT scicom_list ORDER BY topic <> 'Chair',topic,name_last;

This outputs the rows in the order of:

Notice that topic <> 'Chair' is used to select all the rows with 'Chair' first. It then sorts the rows where topic = Chair by name_last.*

*This is a bit counterintuitive since <> equals != based on other feedback in this post.

This syntax can also be used to prioritize multiple categories. For instance, if I want to have "Chair" and then "Vice Chair" listed before the rest of the topics, I use the following

SELECT scicom_list ORDER BY topic <> 'Chair',topic <> 'Vice Chair',topic,name_last;

This outputs the rows in the order of:
Vice Chair

Uncaught TypeError: Cannot read property 'ownerDocument' of undefined

In case you are appending to the DOM, make sure the content is compatible:

modal.find ('div.modal-body').append (content) // check content

ORA-01438: value larger than specified precision allows for this column

This indicates you are trying to put something too big into a column. For example, you have a VARCHAR2(10) column and you are putting in 11 characters. Same thing with number.

This is happening at line 176 of package UMAIN. You would need to go and have a look at that to see what it is up to. Hopefully you can look it up in your source control (or from user_source). Later versions of Oracle report this error better, telling you which column and what value.

How to add link to flash banner

@Michiel is correct to create a button but the code for ActionScript 3 it is a little different - where movieClipName is the name of your 'button'.

movieClipName.addEventListener(MouseEvent.CLICK, callLink);
function callLink:void {
  var url:String = "http://site";
  var request:URLRequest = new URLRequest(url);
  try {
    navigateToURL(request, '_blank');
  } catch (e:Error) {
    trace("Error occurred!");


JUnit: how to avoid "no runnable methods" in test utils classes

Assuming you're in control of the pattern used to find test classes, I'd suggest changing it to match *Test rather than *Test*. That way TestHelper won't get matched, but FooTest will.

AngularJS: How to run additional code after AngularJS has rendered a template?

This post is old, but I change your code to:

scope.$watch("assignments", function (value) {//I change here
  var val = value || null;            
  if (val)
    element.dataTable({"bDestroy": true});

see jsfiddle.

I hope it helps you

Wait until ActiveWorkbook.RefreshAll finishes - VBA

For me, "BackgroundQuery:=False" did not work alone But adding a "DoEvents" resolved problem

.QueryTable.Refresh BackgroundQuery:=False

Call to undefined function curl_init().?

If you're on Windows:

Go to your php.ini file and remove the ; mark from the beginning of the following line:


After you have saved the file you must restart your HTTP server software (e.g. Apache) before this can take effect.

For Ubuntu 13.0 and above, simply use the debundled package. In a terminal type the following to install it and do not forgot to restart server.

sudo apt-get install php-curl

Or if you're using the old PHP5

sudo apt-get install php5-curl


sudo apt-get install php5.6-curl

Then restart apache to activate the package with

sudo service apache2 restart

Determine if JavaScript value is an "integer"?

Use jQuery's IsNumeric method.

if ($.isNumeric(id)) {
   //it's numeric

CORRECTION: that would not ensure an integer. This would:

if ( (id+"").match(/^\d+$/) ) {
   //it's all digits

That, of course, doesn't use jQuery, but I assume jQuery isn't actually mandatory as long as the solution works

How do I find Waldo with Mathematica?

I have a quick solution for finding Waldo using OpenCV.

I used the template matching function available in OpenCV to find Waldo.

To do this a template is needed. So I cropped Waldo from the original image and used it as a template.

enter image description here

Next I called the cv2.matchTemplate() function along with the normalized correlation coefficient as the method used. It returned a high probability at a single region as shown in white below (somewhere in the top left region):

enter image description here

The position of the highest probable region was found using cv2.minMaxLoc() function, which I then used to draw the rectangle to highlight Waldo:

enter image description here

'module' has no attribute 'urlencode'

urllib has been split up in Python 3.

The urllib.urlencode() function is now urllib.parse.urlencode(),

the urllib.urlopen() function is now urllib.request.urlopen().

Jquery set radio button checked, using id and class selectors

" a class and a div."

I assume when you say "div" you mean "id"? Try this:

$('#test2.test1').prop('checked', true);

No need to muck about with your [attributename=value] style selectors because id has its own format as does class, and they're easily combined although given that id is supposed to be unique it should be enough on its own unless your meaning is "select that element only if it currently has the specified class".

Or more generally to select an input where you want to specify a multiple attribute selector:

$('input:radio[class=test1][id=test2]').prop('checked', true);

That is, list each attribute with its own square brackets.

Note that unless you have a pretty old version of jQuery you should use .prop() rather than .attr() for this purpose.

Calculating average of an array list?

sum += i;

You're adding the index; you should be adding the actual item in the ArrayList:

sum += marks.get(i);

Also, to ensure the return value isn't truncated, force one operand to double and change your method signature to double:

return (double)sum / marks.size();

#pragma pack effect

You'd likely only want to use this if you were coding to some hardware (e.g. a memory mapped device) which had strict requirements for register ordering and alignment.

However, this looks like a pretty blunt tool to achieve that end. A better approach would be to code a mini-driver in assembler and give it a C calling interface rather than fumbling around with this pragma.

How to manually trigger click event in ReactJS?

Using React Hooks and the useRef hook.

import React, { useRef } from 'react';

const MyComponent = () => {
    const myInput = useRef(null);

    const clickElement = () => {
        // To simulate a user focusing an input you should use the
        // built in .focus() method.

        // To simulate a click on a button you can use the .click()
        // method.
        // myInput.current?.click();

    return (
            <button onClick={clickElement}>
                Trigger click inside input
            <input ref={myInput} />

Adding placeholder attribute using Jquery

Try something like the following if you want to use pure JavaScript:

document.getElementsByName('link')[0].placeholder='Type here to search';

How to add the JDBC mysql driver to an Eclipse project?

  1. copy mysql-connector-java-5.1.24-bin.jar

  2. Paste it into \Apache Software Foundation\Tomcat 6.0\lib\<--here-->

  3. Restart Your Server from Eclipes.

  4. Done

How to SELECT in Oracle using a DBLINK located in a different schema?

I don't think it is possible to share a database link between more than one user but not all. They are either private (for one user only) or public (for all users).

A good way around this is to create a view in SCHEMA_B that exposes the table you want to access through the database link. This will also give you good control over who is allowed to select from the database link, as you can control the access to the view.

Do like this:

create database link db_link... as before;
create view mytable_view as select * from mytable@db_link;
grant select on mytable_view to myuser;

Splitting String and put it on int array

You are doing Integer division, so you will lose the correct length if the user happens to put in an odd number of inputs - that is one problem I noticed. Because of this, when I run the code with an input of '1,2,3,4,5,6,7' my last value is ignored...

How to use Java property files?

This load the properties file:

Properties prop = new Properties();
InputStream stream = ...; //the stream to the file
try {
} finally {

I use to put the .properties file in a directory where I have all the configuration files, I do not put it together with the class that accesses it, but there are no restrictions here.

For the name... I use .properties for verbosity sake, I don't think you should name it .properties if you don't want.

Format a BigDecimal as String with max 2 decimal digits, removing 0 on decimal part

I used DecimalFormat for formatting the BigDecimal instead of formatting the String, seems no problems with it.

The code is something like this:

bd = bd.setScale(2, BigDecimal.ROUND_DOWN);

DecimalFormat df = new DecimalFormat();




String result = df.format(bd);

Converting string to Date and DateTime

Use strtotime() on your first date then date('Y-m-d') to convert it back:

$time = strtotime('10/16/2003');

$newformat = date('Y-m-d',$time);

echo $newformat;
// 2003-10-16

Make note that there is a difference between using forward slash / and hyphen - in the strtotime() function. To quote from

Dates in the m/d/y or d-m-y formats are disambiguated by looking at the separator between the various components: if the separator is a slash (/), then the American m/d/y is assumed; whereas if the separator is a dash (-) or a dot (.), then the European d-m-y format is assumed.

To avoid potential ambiguity, it's best to use ISO 8601 (YYYY-MM-DD) dates or DateTime::createFromFormat() when possible.

How to extract Month from date in R

Her is another R base approach:

From your example: Some date:


We tell R, "That is a Date"


We extract the month:


output: [1] "January"

Finally, we can convert it to a numerical variable:


outpt: [1] 1

MySQL and GROUP_CONCAT() maximum length

The correct syntax is mysql> SET @@global.group_concat_max_len = integer;
If you do not have the privileges to do this on the server where your database resides then use a query like:
mySQL="SET @@session.group_concat_max_len = 10000;"or a different value.
Next line:
SET objRS = objConn.Execute(mySQL)  your variables may be different.
mySQL="SELECT GROUP_CONCAT(......);" etc
I use the last version since I do not have the privileges to change the default value of 1024 globally (using cPanel).
Hope this helps.

How to install JQ on Mac by command-line?

You can install any application/packages with brew on mac. If you want to know the exact command just search your package on and you will get the set of commands needed to install that package.

First open terminal and install brew

ruby -e "$(curl -fsSL" < /dev/null 2> /dev/null

Now Install jq

brew install jq

Spring @PropertySource using YAML

As it was mentioned @PropertySource doesn't load yaml file. As a workaround load the file on your own and add loaded properties to Environment.

Implemement ApplicationContextInitializer:

public class YamlFileApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
  public void initialize(ConfigurableApplicationContext applicationContext) {
    try {
        Resource resource = applicationContext.getResource("classpath:file.yml");
        YamlPropertySourceLoader sourceLoader = new YamlPropertySourceLoader();
        PropertySource<?> yamlTestProperties = sourceLoader.load("yamlTestProperties", resource, null);
    } catch (IOException e) {
        throw new RuntimeException(e);

Add your initializer to your test:

@SpringApplicationConfiguration(classes = Application.class, initializers = YamlFileApplicationContextInitializer.class)
public class SimpleTest {
  public test(){
    // test your properties

How to create a drop shadow only on one side of an element?

If your background is solid (or you can reproduce it using CSS), you can use linear gradient that way:

div {_x000D_
  background-image: linear-gradient(to top, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0.3) 5px, #fff 5px, #fff 100%)_x000D_

This will generate a 5px gradient at the bottom of the element, from black at 30% opacity to completely transparent. The rest of the element has white background. Of course, changing the last 2 color stops of the linear gradient, you could make the background completely transparent.

Switch case with conditions

What you are doing is to look for (0) or (1) results.

(cnt >= 10 && cnt <= 20) returns either true or false.

--edit-- you can't use case with boolean (logic) experessions. The statement cnt >= 10 returns zero for false or one for true. Hence, it will we case(1) or case(0) which will never match to the length. --edit--

jQuery Datepicker with text input that doesn't allow user input

You should be able to use the readonly attribute on the text input, and jQuery will still be able to edit its contents.

<input type='text' id='foo' readonly='true'>

React "after render" code?

In my experience window.requestAnimationFrame wasn't enough to ensure that the DOM had been fully rendered / reflow-complete from componentDidMount. I have code running that accesses the DOM immediately after a componentDidMount call and using solely window.requestAnimationFrame would result in the element being present in the DOM; however, updates to the element's dimensions aren't reflected yet since a reflow hasn't yet occurred.

The only truly reliable way for this to work was to wrap my method in a setTimeout and a window.requestAnimationFrame to ensure React's current call stack gets cleared before registering for the next frame's render.

function onNextFrame(callback) {
    setTimeout(function () {

If I had to speculate on why this is occurring / necessary I could see React batching DOM updates and not actually applying the changes to the DOM until after the current stack is complete.

Ultimately, if you're using DOM measurements in the code you're firing after the React callbacks you'll probably want to use this method.

How can I check whether a variable is defined in Node.js?

For me, an expression like

if (typeof query !== 'undefined' && query !== null){
   // do stuff

is more complicated than I want for how often I want to use it. That is, testing if a variable is defined/null is something I do frequently. I want such a test to be simple. To resolve this, I first tried to define the above code as a function, but node just gives me a syntax error, telling me the parameter to the function call is undefined. Not useful! So, searching about and working on this bit, I found a solution. Not for everyone perhaps. My solution involves using Sweet.js to define a macro. Here's how I did it:

Here's the macro (filename: macro.sjs):

// I had to install sweet using:
// npm install --save-dev
// See:
// Followed instructions from

// Initially I just had "($x)" in the macro below. But this failed to match with 
// expressions such as "self.x. Adding the :expr qualifier cures things. See

macro isDefined {
  rule {
  } => {
    (( typeof ($x) === 'undefined' || ($x) === null) ? false : true)

// Seems the macros have to be exported

export isDefined;

Here's an example of usage of the macro (in example.sjs):

function Foobar() {
    var self = this;

    self.x = 10;

    console.log(isDefined(y)); // false
    console.log(isDefined(self.x)); // true

module.exports = Foobar;

And here's the main node file:

var sweet = require('sweet.js');

// load all exported macros in `macros.sjs`

// example.sjs uses macros that have been defined and exported in `macros.sjs`
var Foobar = require('./example.sjs');

var x = new Foobar();

A downside of this, aside from having to install Sweet, setup the macro, and load Sweet in your code, is that it can complicate error reporting in Node. It adds a second layer of parsing. Haven't worked with this much yet, so shall see how it goes first hand. I like Sweet though and I miss macros so will try to stick with it!

Link vs compile vs controller

I wanted to add also what the O'Reily AngularJS book by the Google Team has to say:

Controller - Create a controller which publishes an API for communicating across directives. A good example is Directive to Directive Communication

Link - Programmatically modify resulting DOM element instances, add event listeners, and set up data binding.

Compile - Programmatically modify the DOM template for features across copies of a directive, as when used in ng-repeat. Your compile function can also return link functions to modify the resulting element instances.

How to run only one unit test class using Gradle

Below is the command to run a single test class using gradlew command line option:

gradlew.bat Connected**your bundleVariant**AndroidTest -Pandroid.testInstrumentationRunnerArguments.class=com.example.TestClass

Below example to run class com.example.TestClass with variant Variant_1:

gradlew.bat ConnectedVariant_1AndroidTest -Pandroid.testInstrumentationRunnerArguments.class=com.example.TestClass 

Convert alphabet letters to number in Python

Use this function. It converts a string of alphabet to its equivalent digit value:

def convAlph2Num(sent):
    alphArray = list(string.ascii_lowercase)
    alphSet = set(alphArray)
    sentArray = list(sent.lower())
    x = []
    for u in sentArray:
        if u in alphSet:
            u = alphArray.index(u) + 1

Regex - how to match everything except a particular pattern

You could use a look-ahead assertion:


This example matches three digits other than 999.

But if you happen not to have a regular expression implementation with this feature (see Comparison of Regular Expression Flavors), you probably have to build a regular expression with the basic features on your own.

A compatible regular expression with basic syntax only would be:


This does also match any three digits sequence that is not 999.

How to create an infinite loop in Windows batch file?

Here is an example of using the loop:

echo off


set /P M=Input text to encode md5, press ENTER to exit: 
if %M%==%M1% goto end

echo.|set /p ="%M%" | openssl md5

set M1=%M%
Goto begin

This is the simple batch i use when i need to encrypt any message into md5 hash on Windows(openssl required), and the program would loyally repeat itself except given Ctrl+C or empty input.

Detecting when the 'back' button is pressed on a navbar

The best way is to use the UINavigationController delegate methods

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated

Using this you can know what controller is showing the UINavigationController.

if ([viewController isKindOfClass:[HomeController class]]) {
    NSLog(@"Show home controller");

What's the difference between an argument and a parameter?

Generally speaking, the terms parameter and argument are used interchangeably to mean information that is passed into a function.

Yet, from a function's perspective:

  • A parameter is the variable listed inside the parentheses in the function definition.
  • An argument is the value that is sent to the function when it is called.

Viewing full version tree in git

  1. When I'm in my work place with terminal only, I use:

    git log --oneline --graph --color --all --decorate

    enter image description here

  2. When the OS support GUI, I use:

    gitk --all

    enter image description here

  3. When I'm in my home Windows PC, I use my own GitVersionTree

    enter image description here

How to find first element of array matching a boolean condition in JavaScript?

If you're using underscore.js you can use its find and indexOf functions to get exactly what you want:

var index = _.indexOf(your_array, _.find(your_array, function (d) {
    return d === true;


How to save and load cookies using Python + Selenium WebDriver

This is code I used in Windows. It works.

for item in COOKIES.split(';'):
    name,value = item.split('=', 1)
    name=name.replace(' ', '').replace('\r', '').replace('\n', '')
    value = value.replace(' ', '').replace('\r', '').replace('\n', '')
            "domain": "",  # Google Chrome
            "expires": "",
            'path': '/',
            'httpOnly': False,
            'HostOnly': False,
            'Secure': False

error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '0' doesn't match value '2' in main.obj

I had a mismatch between projects: one with multi-byte character set, the other with Unicode. Correcting these to agree on Unicode corrected the problem.

How can I open multiple files using "with open" in Python?

Late answer (8 yrs), but for someone looking to join multiple files into one, the following function may be of help:

def multi_open(_list):
    for x in _list:
            with open(x) as f:
            # print(f"Cannot open file {x}")

fl = ["C:/bdlog.txt", "C:/Jts/tws.vmoptions", "C:/not.exist"]

2018-10-23 19:18:11.361 PROFILE  [Stop Drivers] [1ms]
2018-10-23 19:18:11.361 PROFILE  [Parental uninit] [0ms]
# This file contains VM parameters for Trader Workstation.
# Each parameter should be defined in a separate line and the

Git fails when pushing commit to github

I had the same issue and believe that it has to do with the size of the repo (edited- or the size of a particular file) you are trying to push.

Basically I was able to create new repos and push them to github. But an existing one would not work.

The HTTP error code seems to back me up it is a 'Length Required' error. So maybe it is too large to calc or greated that the max. Who knows.


I found that the problem may be files that are large. I had one update that would not push even though I had successful pushes up to that point. There was only one file in the commit but it happened to be 1.6M

So I added the following config change

git config http.postBuffer 524288000

To allow up to the file size 500M and then my push worked. It may have been that this was the problem initially with pushing a big repo over the http protocol.


the way I could get it to work (EDIT before I modified postBuffer) was to tar up my repo, copy it to a machine that can do git over ssh, and push it to github. Then when you try to do a push/pull from the original server it should work over https. (since it is a much smaller amount of data than an original push).

$rootScope.$broadcast vs. $scope.$emit

They are not doing the same job: $emit dispatches an event upwards through the scope hierarchy, while $broadcast dispatches an event downwards to all child scopes.

How to copy data to clipboard in C#

Clip.exe is an executable in Windows to set the clipboard. Note that this does not work for other operating systems other than Windows, which still sucks.

        /// <summary>
        /// Sets clipboard to value.
        /// </summary>
        /// <param name="value">String to set the clipboard to.</param>
        public static void SetClipboard(string value)
            if (value == null)
                throw new ArgumentNullException("Attempt to set clipboard with null");

            Process clipboardExecutable = new Process(); 
            clipboardExecutable.StartInfo = new ProcessStartInfo // Creates the process
                RedirectStandardInput = true,
                FileName = @"clip", 

            clipboardExecutable.StandardInput.Write(value); // CLIP uses STDIN as input.
            // When we are done writing all the string, close it so clip doesn't wait and get stuck


gpg decryption fails with no secret key error

I just ran into this issue, on the gpg CLI in Arch Linux. I needed to kill the existing "gpg-agent" process, then everything was back to normal ( a new gpg-agent should auto-launch when you invoke the gpg command, again; ...).

  • edit: if the process fails to reload (e.g. within a minute), type gpg-agent in a terminal and/or reboot ...

How to select data where a field has a min value in MySQL?


Something like:

SELECT MIN(price) AS price, pricegroup
FROM articles_prices
WHERE articleID=10
GROUP BY pricegroup
HAVING MIN(price) > 0;

How do I get a list of files in a directory in C++?

Here's an example in C on Linux. That's if, you're on Linux and don't mind doing this small bit in ANSI C.

#include <dirent.h>

DIR *dpdf;
struct dirent *epdf;

dpdf = opendir("./");
if (dpdf != NULL){
   while (epdf = readdir(dpdf)){
      printf("Filename: %s",epdf->d_name);
      // std::cout << epdf->d_name << std::endl;

How do I embed PHP code in JavaScript?

PHP has to be parsed on the server. JavaScript is working in the client's browser.

Having PHP code in a .js file will not work, except you can tell the server to parse the file you want to have as .js before it sends it to the client. And telling the server is the easiest thing in the world: just add .php at the end of the filename.

So, you could name it javascript.php. Or, so you know what this file is PRIMARILY, you could name it javascript.js.php - the server will recognize it as .php and parse it.

What is the default lifetime of a session?

According to a user on site, his efforts to keep session alive failed, so he had to make a workaround.


$Lifetime = 3600;
$separator = (strstr(strtoupper(substr(PHP_OS, 0, 3)), "WIN")) ? "\\" : "/";

$DirectoryPath = dirname(__FILE__) . "{$separator}SessionData";
//in Wamp for Windows the result for $DirectoryPath
//would be C:\wamp\www\your_site\SessionData

is_dir($DirectoryPath) or mkdir($DirectoryPath, 0777);

if (ini_get("session.use_trans_sid") == true) {
    ini_set("url_rewriter.tags", "");
    ini_set("session.use_trans_sid", false);


ini_set("session.gc_maxlifetime", $Lifetime);
ini_set("session.gc_divisor", "1");
ini_set("session.gc_probability", "1");
ini_set("session.cookie_lifetime", "0");
ini_set("session.save_path", $DirectoryPath);


In SessionData folder it will be stored text files for holding session information, each file would be have a name similar to "sess_a_big_hash_here".

Moving matplotlib legend outside of the axis makes it cutoff by the figure box

Here is another, very manual solution. You can define the size of the axis and paddings are considered accordingly (including legend and tickmarks). Hope it is of use to somebody.

Example (axes size are the same!):

enter image description here


# Plot table

colmap = [(0,0,1) #blue
         ,(1,0,0) #red
         ,(0,1,0) #green
         ,(1,1,0) #yellow
         ,(1,0,1) #magenta
         ,(1,0.5,0.5) #pink
         ,(0.5,0.5,0.5) #gray
         ,(0.5,0,0) #brown
         ,(1,0.5,0) #orange

import matplotlib.pyplot as plt
import numpy as np

import collections
df = collections.OrderedDict()
df['labels']        = ['GWP100a\n[kgCO2eq]\n\nasedf\nasdf\nadfs','human\n[pts]','ressource\n[pts]'] 
df['all-petroleum long name'] = [3,5,2]
df['all-electric']  = [5.5, 1, 3]
df['HEV']           = [3.5, 2, 1]
df['PHEV']          = [3.5, 2, 1]

numLabels = len(df.values()[0])
numItems = len(df)-1
posX = np.arange(numLabels)+1
width = 1.0/(numItems+1)

fig = plt.figure(figsize=(2,2))
ax = fig.add_subplot(111)
for iiItem in range(1,numItems+1):*width, df.values()[iiItem], width, color=colmap[iiItem-1], label=df.keys()[iiItem])
ax.set(xticks=posX+width*(0.5*numItems), xticklabels=df['labels'])

# Change padding and margins, insert legend

fig.tight_layout() #tight margins
leg = ax.legend(loc='upper left', bbox_to_anchor=(1.02, 1), borderaxespad=0)
plt.draw() #to know size of legend

padLeft   = ax.get_position().x0 * fig.get_size_inches()[0]
padBottom = ax.get_position().y0 * fig.get_size_inches()[1]
padTop    = ( 1 - ax.get_position().y0 - ax.get_position().height ) * fig.get_size_inches()[1]
padRight  = ( 1 - ax.get_position().x0 - ax.get_position().width ) * fig.get_size_inches()[0]
dpi       = fig.get_dpi()
padLegend = ax.get_legend().get_frame().get_width() / dpi 

widthAx = 3 #inches
heightAx = 3 #inches
widthTot = widthAx+padLeft+padRight+padLegend
heightTot = heightAx+padTop+padBottom

# resize ipython window (optional)
posScreenX = 1366/2-10 #pixel
posScreenY = 0 #pixel
canvasPadding = 6 #pixel
canvasBottom = 40 #pixel
ipythonWindowSize = '{0}x{1}+{2}+{3}'.format(int(round(widthTot*dpi))+2*canvasPadding
plt.draw() #to resize ipython window. Has to be done BEFORE figure resizing!

# set figure size and ax position
ax.set_position([padLeft/widthTot, padBottom/heightTot, widthAx/widthTot, heightAx/heightTot])


Joins in update statements are non-standard and not supported by all vendors. What you're trying to do can be accomplished with a sub-select:

  firstfield = (select 'stuff' concat something from file2 where substr(file1.field1, 10, 20) = substr(,1,10) )
where like 'BLAH%'

How to unpack and pack pkg file?

If you are experiencing errors during PKG installation following the accepted answer, I will give you another procedure that worked for me (please note the little changes to xar, cpio and mkbom commands):

mkdir Foo
cd Foo
xar -xf ../Foo.pkg
cd foo.pkg
cat Payload | gunzip -dc | cpio -i
# edit*
rm Payload
find ./ | cpio -o --format odc --owner 0:80 | gzip -c > Payload
mkbom -u 0 -g 80 Bom # or edit Bom
# edit PackageInfo
rm -rf
cd ..
xar --compression none -cf ../Foo-new.pkg

The resulted PKG will have no compression, cpio now uses odc format and specify the owner of the file as well as mkbom.

Does a `+` in a URL scheme/host/path represent a space?

  • Percent encoding in the path section of a URL is expected to be decoded, but
  • any + characters in the path component is expected to be treated literally.

To be explicit: + is only a special character in the query component.

What is REST? Slightly confused

The basic idea is that instead of having an ongoing connection to the server, you make a request, get some data, show that to a user, but maybe not all of it, and then when the user does something which calls for more data, or to pass some up to the server, the client initiates a change to a new state.

How to switch a user per task or set of tasks?

A solution is to use the include statement with remote_user var (describe there : but it has to be done at playbook instead of task level.

Convert a string to a double - is this possible?

For arbitrary precision mathematics PHP offers the Binary Calculator which supports numbers of any size and precision, represented as strings.

$s = '1234.13';
$double = bcadd($s,'0',2);

PHP: bcadd

Force file download with php using header()

Based on Farhan Sahibole's answer:

        header('Content-Disposition: attachment; filename=Image.png');
        header('Content-Type: application/octet-stream'); // Downloading on Android might fail without this


This is all I needed for this to work. I stripped off anything that isn't required for this to work.

Key is to use ob_clean();

Extract file basename without path and extension in bash

If you want to play nice with Windows file paths (under Cygwin) you can also try this:


This will account for backslash separators when using BaSH on Windows.

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

The error "only length-1 arrays can be converted to Python scalars" is raised when the function expects a single value but you pass an array instead.

If you look at the call signature of, you'll see that it accepts a single value, not an array. In general, if you want to apply a function that accepts a single element to every element in an array, you can use np.vectorize:

import numpy as np
import matplotlib.pyplot as plt

def f(x):
f2 = np.vectorize(f)
x = np.arange(1, 15.1, 0.1)
plt.plot(x, f2(x))

You can skip the definition of f(x) and just pass to the vectorize function: f2 = np.vectorize(

Note that np.vectorize is just a convenience function and basically a for loop. That will be inefficient over large arrays. Whenever you have the possibility, use truly vectorized functions or methods (like astype(int) as @FFT suggests).

How to disassemble a binary executable in Linux to get the assembly code?

ht editor can disassemble binaries in many formats. It is similar to Hiew, but open source.

To disassemble, open a binary, then press F6 and then select elf/image.

Java decimal formatting using String.format?

Yes you can do it with String.format:

String result = String.format("%.2f", 10.0 / 3.0);
// result:  "3.33"

result = String.format("%.3f", 2.5);
// result:  "2.500"

Ways to circumvent the same-origin policy

The Reverse Proxy method

  • Method type: Ajax

Setting up a simple reverse proxy on the server, will allow the browser to use relative paths for the Ajax requests, while the server would be acting as a proxy to any remote location.

If using mod_proxy in Apache, the fundamental configuration directive to set up a reverse proxy is the ProxyPass. It is typically used as follows:

ProxyPass     /ajax/

In this case, the browser would be able to request /ajax/web_service.xml as a relative URL, but the server would serve this by acting as a proxy to

One interesting feature of the this method is that the reverse proxy can easily distribute requests towards multiple back-ends, thus acting as a load balancer.

Python: printing a file to stdout

you can also try this

print ''.join(file('example.txt'))

How To Save Canvas As An Image With canvas.toDataURL()?

I created a small library that does this (along with some other handy conversions). It's called reimg, and it's really simple to use.


What __init__ and self do in Python?

note that self could actually be any valid python identifier. For example, we could just as easily write, from Chris B's example:

class A(object):
    def __init__(foo):
        foo.x = 'Hello'

    def method_a(bar, foo):
        print bar.x + ' ' + foo

and it would work exactly the same. It is however recommended to use self because other pythoners will recognize it more easily.

Git - Pushing code to two remotes

In recent versions of Git you can add multiple pushurls for a given remote. Use the following to add two pushurls to your origin:

git remote set-url --add --push origin git://original/repo.git
git remote set-url --add --push origin git://another/repo.git

So when you push to origin, it will push to both repositories.

UPDATE 1: Git and 1.8.1 (and possibly other versions) seem to have a bug that causes --add to replace the original URL the first time you use it, so you need to re-add the original URL using the same command. Doing git remote -v should reveal the current URLs for each remote.

UPDATE 2: Junio C. Hamano, the Git maintainer, explained it's how it was designed. Doing git remote set-url --add --push <remote_name> <url> adds a pushurl for a given remote, which overrides the default URL for pushes. However, you may add multiple pushurls for a given remote, which then allows you to push to multiple remotes using a single git push. You can verify this behavior below:

$ git clone git://original/repo.git
$ git remote -v
origin  git://original/repo.git (fetch)
origin  git://original/repo.git (push)
$ git config -l | grep '^remote\.'

Now, if you want to push to two or more repositories using a single command, you may create a new remote named all (as suggested by @Adam Nelson in comments), or keep using the origin, though the latter name is less descriptive for this purpose. If you still want to use origin, skip the following step, and use origin instead of all in all other steps.

So let's add a new remote called all that we'll reference later when pushing to multiple repositories:

$ git remote add all git://original/repo.git
$ git remote -v
all git://original/repo.git (fetch)               <-- ADDED
all git://original/repo.git (push)                <-- ADDED
origin  git://original/repo.git (fetch)
origin  git://original/repo.git (push)
$ git config -l | grep '^remote\.all'
remote.all.url=git://original/repo.git            <-- ADDED
remote.all.fetch=+refs/heads/*:refs/remotes/all/* <-- ADDED

Then let's add a pushurl to the all remote, pointing to another repository:

$ git remote set-url --add --push all git://another/repo.git
$ git remote -v
all git://original/repo.git (fetch)
all git://another/repo.git (push)                 <-- CHANGED
origin  git://original/repo.git (fetch)
origin  git://original/repo.git (push)
$ git config -l | grep '^remote\.all'
remote.all.pushurl=git://another/repo.git         <-- ADDED

Here git remote -v shows the new pushurl for push, so if you do git push all master, it will push the master branch to git://another/repo.git only. This shows how pushurl overrides the default url (remote.all.url).

Now let's add another pushurl pointing to the original repository:

$ git remote set-url --add --push all git://original/repo.git
$ git remote -v
all git://original/repo.git (fetch)
all git://another/repo.git (push)
all git://original/repo.git (push)                <-- ADDED
origin  git://original/repo.git (fetch)
origin  git://original/repo.git (push)
$ git config -l | grep '^remote\.all'
remote.all.pushurl=git://original/repo.git        <-- ADDED

You see both pushurls we added are kept. Now a single git push all master will push the master branch to both git://another/repo.git and git://original/repo.git.

powershell is missing the terminator: "

This can also occur when the path ends in a '' followed by the closing quotation mark. e.g. The following line is passed as one of the arguments and this is not right:


instead pass that argument as shown below so that the last backslash is escaped instead of escaping the quotation mark.


How can I detect keydown or keypress event in angular.js?

You were on the right track with your "ng-keydown" attribute on the input, but you missed a simple step. Just because you put the ng-keydown attribute there, doesn't mean angular knows what to do with it. That's where "directives" come into play. You used the attribute correctly, but you now need to write a directive that will tell angular what to do when it sees that attribute on an html element.

The following is an example of how you would do that. We'll rename the directive from ng-keydown to on-keydown (to avoid breaking the "best practice" found here):

var mod = angular.module('mydirectives');
mod.directive('onKeydown', function() {
    return {
        restrict: 'A',
        link: function(scope, elem, attrs) {
             // this next line will convert the string
             // function name into an actual function
             var functionToCall = scope.$eval(attrs.ngKeydown);
             elem.on('keydown', function(e){
                  // on the keydown event, call my function
                  // and pass it the keycode of the key
                  // that was pressed
                  // ex: if ENTER was pressed, e.which == 13

The directive simple tells angular that when it sees an HTML attribute called "ng-keydown", it should listen to the element that has that attribute and call whatever function is passed to it. In the html you would have the following:

<input type="text" on-keydown="onKeydown">

And then in your controller (just like you already had), you would add a function to your controller's scope that is called "onKeydown", like so:

$scope.onKeydown = function(keycode){
    // do something with the keycode

Hopefully that helps either you or someone else who wants to know

How can I force component to re-render with hooks in React?

You can (ab)use normal hooks to force a rerender by taking advantage of the fact that React doesn't print booleans in JSX code

// create a hook
const [forceRerender, setForceRerender] = React.useState(true);

// ...put this line where you want to force a rerender

// ...make sure that {forceRerender} is "visible" in your js code
// ({forceRerender} will not actually be visible since booleans are
// not printed, but updating its value will nonetheless force a
// rerender)
return (

XSL xsl:template match="/"

The value of the match attribute of the <xsl:template> instruction must be a match pattern.

Match patterns form a subset of the set of all possible XPath expressions. The first, natural, limitation is that a match pattern must select a set of nodes. There are also other limitations. In particular, reverse axes are not allowed in the location steps (but can be specified within the predicates). Also, no variable or parameter references are allowed in XSLT 1.0, but using these is legal in XSLT 2.x.

/ in XPath denotes the root or document node. In XPath 2.0 (and hence XSLT 2.x) this can also be written as document-node().

A match pattern can contain the // abbreviation.

Examples of match patterns:

<xsl:template match="table">

can be applied on any element named table.

<xsl:template match="x/y">

can be applied on any element named y whose parent is an element named x.

<xsl:template match="*">

can be applied to any element.

<xsl:template match="/*">

can be applied only to the top element of an XML document.

<xsl:template match="@*">

can be applied to any attribute.

<xsl:template match="text()">

can be applied to any text node.

<xsl:template match="comment()">

can be applied to any comment node.

<xsl:template match="processing-instruction()">

can be applied to any processing instruction node.

<xsl:template match="node()">

can be applied to any node: element, text, comment or processing instructon.

What is wrong with this code that uses the mysql extension to fetch data from a database in PHP?

If this is the code you have, then you will get an error because, you are reassigning $row while in the loop, so you would never be able to iterate over the results. Replace

$rows = $rows['Name'];


$name = $rows['Name']'

So your code would look like

WHILE ($rows = mysql_fetch_array($query)):

   $name = $rows['Name'];
   $address = $rows['Address'];
   $email = $rows['Email'];
   $subject = $rows['Subject'];
   $comment = $rows['Comment'];

Also I am assuming that the column names in the table users are Name, Address, Email etc. and not name,address, email. Remember that every variable name/field nameh is case sensitive.

bash shell nested for loop

The question does not contain a nested loop, just a single loop. But THIS nested version works, too:

# for i in c d; do for j in a b; do echo $i $j; done; done
c a
c b
d a
d b

Add rows to CSV File in powershell

To simply append to a file in powershell,you can use add-content.

So, to only add a new line to the file, try the following, where $YourNewDate and $YourDescription contain the desired values.

$NewLine = "{0},{1}" -f $YourNewDate,$YourDescription
$NewLine | add-content -path $file


"{0},{1}" -f $YourNewDate,$YourDescription | add-content -path $file

This will just tag the new line to the end of the .csv, and will not work for creating new .csv files where you will need to add the header.

Store boolean value in SQLite

SQLite Boolean Datatype:
SQLite does not have a separate Boolean storage class. Instead, Boolean values are stored as integers 0 (false) and 1 (true).

You can convert boolean to int in this way:

int flag = (boolValue)? 1 : 0;

You can convert int back to boolean as follows:

 // Select COLUMN_NAME  values from db. 
 // This will be integer value, you can convert this int value back to Boolean as follows
Boolean flag2 = (intValue == 1)? true : false;

If you want to explore sqlite, here is a tutorial.
I have given one answer here. It is working for them.

process.waitFor() never returns

There are many reasons that waitFor() doesn't return.

But it usually boils down to the fact that the executed command doesn't quit.

This, again, can have many reasons.

One common reason is that the process produces some output and you don't read from the appropriate streams. This means that the process is blocked as soon as the buffer is full and waits for your process to continue reading. Your process in turn waits for the other process to finish (which it won't because it waits for your process, ...). This is a classical deadlock situation.

You need to continually read from the processes input stream to ensure that it doesn't block.

There's a nice article that explains all the pitfalls of Runtime.exec() and shows ways around them called "When Runtime.exec() won't" (yes, the article is from 2000, but the content still applies!)

Default Xmxsize in Java 8 (max heap size)

As of 8, May, 2019:

JVM heap size depends on system configuration, meaning:

a) client jvm vs server jvm

b) 32bit vs 64bit.


1) updation from J2SE5.0:
2) brief answer:
3) detailed answer:
4) client vs server:

Summary: (Its tough to understand from the above links. So summarizing them here)

1) Default maximum heap size for Client jvm is 256mb (there is an exception, read from links above).

2) Default maximum heap size for Server jvm of 32bit is 1gb and of 64 bit is 32gb (again there are exceptions here too. Kindly read that from the links).

So default maximum jvm heap size is: 256mb or 1gb or 32gb depending on VM, above.

How to get the absolute path to the public_html folder?

You just need to create an offset bypass to how far you want the backwards reading to go. So, we use getcwd() to get the path and explode (split into array) to fetch the data between $root and the ending of the path.

function getRoot($root = "public_html") {
    return explode($root, getcwd())[0].$root."/";

Laravel 5 Clear Views Cache

Here is a helper that I wrote to solve this issue for my projects. It makes it super simple and easy to be able to clear everything out quickly and with a single command.

How to write new line character to a file in Java

    PrintWriter out = null; // for writting in file    
    String newLine = System.getProperty("line.separator"); // taking new line 
    out.print("1st Line"+newLine); // print with new line
    out.print("2n Line"+newLine);  // print with new line

jQuery-UI datepicker default date

Seeing that:

Set the date to highlight on first opening if the field is blank. Specify either an actual date via a Date object or as a string in the current dateFormat, or a number of days from today (e.g. +7) or a string of values and periods ('y' for years, 'm' for months, 'w' for weeks, 'd' for days, e.g. '+1m +7d'), or null for today.

If the current dateFormat is not recognized, you can still use the Date object using new Date(year, month, day)

In your example, this should work (I didn't test it) :

<script type="text/javascript">
$(function() {               
    $("#birthdate" ).datepicker({
        changeMonth: true,
        changeYear: true,
        yearRange: '1920:2010',
        dateFormat : 'dd-mm-yy',
        defaultDate: new Date(1985,01,01)

How to generate classes from wsdl using Maven and wsimport?

The key here is keep option of wsimport. And it is configured using element in About keep from the wsimport documentation :

-keep                     keep generated files

How to clear jQuery validation error messages?

I think we just need to enter the inputs to clean everything

$("#your_div").click(function() {

Python safe method to get value of nested dictionary

A simple class that can wrap a dict, and retrieve based on a key:

class FindKey(dict):
    def get(self, path, default=None):
        keys = path.split(".")
        val = None

        for key in keys:
            if val:
                if isinstance(val, list):
                    val = [v.get(key, default) if v else None for v in val]
                    val = val.get(key, default)
                val = dict.get(self, key, default)

            if not val:

        return val

For example:

person = {'person':{'name':{'first':'John'}}}
FindDict(person).get('') # == 'John'

If the key doesn't exist, it returns None by default. You can override that using a default= key in the FindDict wrapper -- for example`:

FindDict(person, default='').get('') # == doesn't exist, so ''

How best to read a File into List<string>

//this is only good in .NET 4
//read your file:
List<string> ReadFile = File.ReadAllLines(@"C:\TEMP\FILE.TXT").ToList();

//manipulate data here
foreach(string line in ReadFile)
    //do something here

//write back to your file:
File.WriteAllLines(@"C:\TEMP\FILE2.TXT", ReadFile);

How to find largest objects in a SQL Server database?

@marc_s's answer is very great and I've been using it for few years. However, I noticed that the script misses data in some columnstore indexes and doesn't show complete picture. E.g. when you do SUM(TotalSpace) against the script and compare it with total space database property in Management Studio the numbers don't match in my case (Management Studio shows larger numbers). I modified the script to overcome this issue and extended it a little bit:

    tables.[name] as table_name,
    schemas.[name] as schema_name,
    isnull(db_name(dm_db_index_usage_stats.database_id), 'Unknown') as database_name,
    sum(allocation_units.total_pages) * 8 as total_space_kb,
    cast(round(((sum(allocation_units.total_pages) * 8) / 1024.00), 2) as numeric(36, 2)) as total_space_mb,
    sum(allocation_units.used_pages) * 8 as used_space_kb,
    cast(round(((sum(allocation_units.used_pages) * 8) / 1024.00), 2) as numeric(36, 2)) as used_space_mb,
    (sum(allocation_units.total_pages) - sum(allocation_units.used_pages)) * 8 as unused_space_kb,
    cast(round(((sum(allocation_units.total_pages) - sum(allocation_units.used_pages)) * 8) / 1024.00, 2) as numeric(36, 2)) as unused_space_mb,
    count(distinct indexes.index_id) as indexes_count,
    max(dm_db_partition_stats.row_count) as row_count,
    iif(max(isnull(user_seeks, 0)) = 0 and max(isnull(user_scans, 0)) = 0 and max(isnull(user_lookups, 0)) = 0, 1, 0) as no_reads,
    iif(max(isnull(user_updates, 0)) = 0, 1, 0) as no_writes,
    max(isnull(user_seeks, 0)) as user_seeks,
    max(isnull(user_scans, 0)) as user_scans,
    max(isnull(user_lookups, 0)) as user_lookups,
    max(isnull(user_updates, 0)) as user_updates,
    max(last_user_seek) as last_user_seek,
    max(last_user_scan) as last_user_scan,
    max(last_user_lookup) as last_user_lookup,
    max(last_user_update) as last_user_update,
    max(tables.create_date) as create_date,
    max(tables.modify_date) as modify_date
    left join sys.schemas on schemas.schema_id = tables.schema_id
    left join sys.indexes on tables.object_id = indexes.object_id
    left join sys.partitions on indexes.object_id = partitions.object_id and indexes.index_id = partitions.index_id
    left join sys.allocation_units on partitions.partition_id = allocation_units.container_id
    left join sys.dm_db_index_usage_stats on tables.object_id = dm_db_index_usage_stats.object_id and indexes.index_id = dm_db_index_usage_stats.index_id
    left join sys.dm_db_partition_stats on tables.object_id = dm_db_partition_stats.object_id and indexes.index_id = dm_db_partition_stats.index_id
group by schemas.[name], tables.[name], isnull(db_name(dm_db_index_usage_stats.database_id), 'Unknown')
order by 5 desc

Hope it will be helpful for someone. This script was tested against large TB-wide databases with hundreds of different tables, indexes and schemas.

Pretty git branch graphs

This is my take on this matter:




git hist - Show the history of current branch

git hist --all - Show the graph of all branches (including remotes)

git hist master devel - Show the relationship between two or more branches

git hist --branches - Show all local branches

Add --topo-order to sort commits topologically, instead of by date (default in this alias)


  • Looks just like plain --decorate, so with separate colors for different branch names
  • Adds committer email
  • Adds commit relative and absolute date
  • Sorts commits by date


git config --global alias.hist "log --graph --date-order --date=short \
--pretty=format:'%C(auto)%h%d %C(reset)%s %C(bold blue)%ce %C(reset)%C(green)%cr (%cd)'"

Center a 'div' in the middle of the screen, even when the page is scrolled up or down?

I just found a new trick to center a box in the middle of the screen even if you don't have fixed dimensions. Let's say you would like a box 60% width / 60% height. The way to make it centered is by creating 2 boxes: a "container" box that position left: 50% top :50%, and a "text" box inside with reverse position left: -50%; top :-50%;

It works and it's cross browser compatible.

Check out the code below, you probably get a better explanation:

jQuery('.close a, .bg', '#message').on('click', function() {_x000D_
  return false;_x000D_
html, body {_x000D_
  min-height: 100%;_x000D_
#message {_x000D_
  height: 100%;_x000D_
  left: 0;_x000D_
  position: fixed;_x000D_
  top: 0;_x000D_
  width: 100%;_x000D_
#message .container {_x000D_
  height: 60%;_x000D_
  left: 50%;_x000D_
  position: absolute;_x000D_
  top: 50%;_x000D_
  z-index: 10;_x000D_
  width: 60%;_x000D_
#message .container .text {_x000D_
  background: #fff;_x000D_
  height: 100%;_x000D_
  left: -50%;_x000D_
  position: absolute;_x000D_
  top: -50%;_x000D_
  width: 100%;_x000D_
#message .bg {_x000D_
  background: rgba(0, 0, 0, 0.5);_x000D_
  height: 100%;_x000D_
  left: 0;_x000D_
  position: absolute;_x000D_
  top: 0;_x000D_
  width: 100%;_x000D_
  z-index: 9;_x000D_
<script src=""></script>_x000D_
<div id="message">_x000D_
  <div class="container">_x000D_
    <div class="text">_x000D_
      <p>The message</p>_x000D_
      <p class="close"><a href="#">Close Window</a></p>_x000D_
  <div class="bg"></div>_x000D_

SQL Server : check if variable is Empty or NULL for WHERE clause

If you can use some dynamic query, you can use LEN . It will give false on both empty and null string. By this way you can implement the option parameter.

ALTER PROCEDURE [dbo].[psProducts] 
(@SearchType varchar(50))

DECLARE @Query nvarchar(max) = N'
    FROM [Product] P'
    -- if @Searchtype is not null then use the where clause
    SET @Query = CASE WHEN LEN(@SearchType) > 0 THEN @Query + ' WHERE p.[Type] = ' + ''''+ @SearchType + '''' ELSE @Query END   

    EXECUTE sp_executesql @Query
    PRINT @Query

How to safely open/close files in python 2.4

No need to close the file according to the docs if you use with:

It is good practice to use the with keyword when dealing with file objects. This has the advantage that the file is properly closed after its suite finishes, even if an exception is raised on the way. It is also much shorter than writing equivalent try-finally blocks:

>>> with open('workfile', 'r') as f:
...     read_data =
>>> f.closed

More here:

how to show confirmation alert with three buttons 'Yes' 'No' and 'Cancel' as it shows in MS Word

This cannot be done with the native javascript dialog box, but a lot of javascript libraries include more flexible dialogs. You can use something like jQuery UI's dialog box for this.

See also these very similar questions:

Here's an example, as demonstrated in this jsFiddle:

    <script type="text/javascript" src=""></script>
    <script type="text/javascript" src=""></script>
    <link rel="stylesheet" type="text/css" href="/css/normalize.css">
    <link rel="stylesheet" type="text/css" href="/css/result-light.css">
    <link rel="stylesheet" type="text/css" href="">
    <a class="checked" href="">Click here</a>
    <script type="text/javascript">

        $(function() {
            $('.checked').click(function(e) {
                var dialog = $('<p>Are you sure?</p>').dialog({
                    buttons: {
                        "Yes": function() {alert('you chose yes');},
                        "No":  function() {alert('you chose no');},
                        "Cancel":  function() {
                            alert('you chose cancel');


CSV parsing in Java - working example..?

My approach would not be to start by writing your own API. Life's too short, and there are more pressing problems to solve. In this situation, I typically:

  • Find a library that appears to do what I want. If one doesn't exist, then implement it.
  • If a library does exist, but I'm not sure it'll be suitable for my needs, write a thin adapter API around it, so I can control how it's called. The adapter API expresses the API I need, and it maps those calls to the underlying API.
  • If the library doesn't turn out to be suitable, I can swap another one in underneath the adapter API (whether it's another open source one or something I write myself) with a minimum of effort, without affecting the callers.

Start with something someone has already written. Odds are, it'll do what you want. You can always write your own later, if necessary. OpenCSV is as good a starting point as any.

Fatal Error: Allowed Memory Size of 134217728 Bytes Exhausted (CodeIgniter + XML-RPC)

The most common cause of this error message for me is omitting the "++" operator from a PHP "for" statement. This causes the loop to continue forever, no matter how much memory you allow to be used. It is a simple syntax error, yet is difficult for the compiler or runtime system to detect. It is easy for us to correct if we think to look for it!

But suppose you want a general procedure for stopping such a loop early and reporting the error? You can simply instrument each of your loops (or at least the innermost loops) as discussed below.

In some cases such as recursion inside exceptions, set_time_limit fails, and the browser keeps trying to load the PHP output, either with an infinite loop or with the fatal error message which is the topic of this question.

By reducing the allowed allocation size near the beginning of your code you might be able to prevent the fatal error, as discussed in the other answers.

Then you may be left with a program that terminates, but is still difficult to debug.

Whether or not your program terminates, instrument your code by inserting BreakLoop() calls inside your program to gain control and find out what loop or recursion in your program is causing the problem.

The definition of BreakLoop is as follows:

function BreakLoop($MaxRepetitions=500,$LoopSite="unspecified")
    static $Sites=[];
    if (!@$Sites[$LoopSite] || !$MaxRepetitions)
        $Sites[$LoopSite]=['n'=>0, 'if'=>0];
    if (!$MaxRepetitions)
    if (++$Sites[$LoopSite]['n'] >= $MaxRepetitions)
        $S=debug_backtrace(); // array_reverse
        exit("*** Loop for site $LoopSite was interrupted after $MaxRepetitions repetitions. In file $File at line $Line.");
    } // BreakLoop

The $LoopSite argument can be the name of a function in your code. It isn't really necessary, since the error message you will get will point you to the line containing the BreakLoop() call.

Setting attribute disabled on a SPAN element does not prevent click events

Try this:

$("span").css("pointer-events", "none");

you can enabled those back by

$("span").css("pointer-events", "auto");

converting a base 64 string to an image and saving it

In my case it works only with two line of code. Test the below C# code:

String dirPath = "C:\myfolder\";
String imgName = "my_mage_name.bmp";

byte[] imgByteArray = Convert.FromBase64String("your_base64_string");
File.WriteAllBytes(dirPath + imgName, imgByteArray);

That's it. Kindly up vote if you really find this solution works for you. Thanks in advance.

Python Pylab scatter plot error bars (the error on each point is unique)

This is almost like the other answer but you don't need a scatter plot at all, you can simply specify a scatter-plot-like format (fmt-parameter) for errorbar:

import matplotlib.pyplot as plt
x = [1, 2, 3, 4]
y = [1, 4, 9, 16]
e = [0.5, 1., 1.5, 2.]
plt.errorbar(x, y, yerr=e, fmt='o')


enter image description here

A list of the avaiable fmt parameters can be found for example in the plot documentation:

character   description
'-'     solid line style
'--'    dashed line style
'-.'    dash-dot line style
':'     dotted line style
'.'     point marker
','     pixel marker
'o'     circle marker
'v'     triangle_down marker
'^'     triangle_up marker
'<'     triangle_left marker
'>'     triangle_right marker
'1'     tri_down marker
'2'     tri_up marker
'3'     tri_left marker
'4'     tri_right marker
's'     square marker
'p'     pentagon marker
'*'     star marker
'h'     hexagon1 marker
'H'     hexagon2 marker
'+'     plus marker
'x'     x marker
'D'     diamond marker
'd'     thin_diamond marker
'|'     vline marker
'_'     hline marker

Check if something is (not) in a list in Python

The bug is probably somewhere else in your code, because it should work fine:

>>> 3 not in [2, 3, 4]
>>> 3 not in [4, 5, 6]

Or with tuples:

>>> (2, 3) not in [(2, 3), (5, 6), (9, 1)]
>>> (2, 3) not in [(2, 7), (7, 3), "hi"]

How to convert int[] into List<Integer> in Java?;

How to calculate Date difference in Hive

I would try this first

select * from employee where month(current_date)-3 = month(joining_date)

How do I implement interfaces in python?

Implementing interfaces with abstract base classes is much simpler in modern Python 3 and they serve a purpose as an interface contract for plug-in extensions.

Create the interface/abstract base class:

from abc import ABC, abstractmethod

class AccountingSystem(ABC):

    def create_purchase_invoice(self, purchase):

    def create_sale_invoice(self, sale):
        log.debug('Creating sale invoice', sale)

Create a normal subclass and override all abstract methods:

class GizmoAccountingSystem(AccountingSystem):

    def create_purchase_invoice(self, purchase):

    def create_sale_invoice(self, sale):

You can optionally have common implementation in the abstract methods as in create_sale_invoice(), calling it with super() explicitly in the subclass as above.

Instantiation of a subclass that does not implement all the abstract methods fails:

class IncompleteAccountingSystem(AccountingSystem):

>>> accounting = IncompleteAccountingSystem()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Can't instantiate abstract class IncompleteAccountingSystem with abstract methods
create_purchase_invoice, create_sale_invoice

You can also have abstract properties, static and class methods by combining corresponding annotations with @abstractmethod.

Abstract base classes are great for implementing plugin-based systems. All imported subclasses of a class are accessible via __subclasses__(), so if you load all classes from a plugin directory with importlib.import_module() and if they subclass the base class, you have direct access to them via __subclasses__() and you can be sure that the interface contract is enforced for all of them during instantiation.

Here's the plugin loading implementation for the AccountingSystem example above:

from importlib import import_module

class AccountingSystem(ABC):

    _instance = None

    def instance(cls):
        if not cls._instance:
            module_name = settings.ACCOUNTING_SYSTEM_MODULE_NAME
            subclasses = cls.__subclasses__()
            if len(subclasses) > 1:
                raise InvalidAccountingSystemError('More than one '
                        f'accounting module: {subclasses}')
            if not subclasses or module_name not in str(subclasses[0]):
                raise InvalidAccountingSystemError('Accounting module '
                        f'{module_name} does not exist or does not '
                        'subclass AccountingSystem')
            cls._instance = subclasses[0]()
        return cls._instance

Then you can access the accounting system plugin object through the AccountingSystem class:

>>> accountingsystem = AccountingSystem.instance()

(Inspired by this PyMOTW-3 post.)

Casting int to bool in C/C++

The following cites the C11 standard (final draft). When any scalar value is converted to _Bool, the result is 0 if the value compares equal to 0; otherwise, the result is 1.

bool (mapped by stdbool.h to the internal name _Bool for C) itself is an unsigned integer type:

... The type _Bool and the unsigned integer types that correspond to the standard signed integer types are the standard unsigned integer types.

According to 6.2.5p2:

An object declared as type _Bool is large enough to store the values 0 and 1.

AFAIK these definitions are semantically identical to C++ - with the minor difference of the built-in(!) names. bool for C++ and _Bool for C.

Note that C does not use the term rvalues as C++ does. However, in C pointers are scalars, so assigning a pointer to a _Bool behaves as in C++.

SQL update fields of one table from fields of another one

you can build and execute dynamic sql to do this, but its really not ideal

Given a DateTime object, how do I get an ISO 8601 date in string format?

Using Newtonsoft.Json, you can do



How to check a channel is closed or not without reading it?

You could set your channel to nil in addition to closing it. That way you can check if it is nil.

example in the playground:

edit: This is actually a bad solution as demonstrated in the next example, because setting the channel to nil in a function would break it:

Update div with jQuery ajax response html

It's also possible to use jQuery's .load()

$('#submitform').click(function() {
  $('#showresults').load('getinfo.asp #showresults', {
    txtsearch: $('#appendedInputButton').val()
  }, function() {
    // alert('Load was performed.')
    // $('#showresults').slideDown('slow')

unlike $.get(), allows us to specify a portion of the remote document to be inserted. This is achieved with a special syntax for the url parameter. If one or more space characters are included in the string, the portion of the string following the first space is assumed to be a jQuery selector that determines the content to be loaded.

We could modify the example above to use only part of the document that is fetched:

$( "#result" ).load( "ajax/test.html #container" );

When this method executes, it retrieves the content of ajax/test.html, but then jQuery parses the returned document to find the element with an ID of container. This element, along with its contents, is inserted into the element with an ID of result, and the rest of the retrieved document is discarded.

Pass an array of integers to ASP.NET Web API?

Easy way to send array params to web api


public IEnumerable<Category> GetCategories([FromUri]int[] categoryIds){
 // code to retrieve categories from database

Jquery : send JSON object as request params

//success response

It will generate your request URL like ../api/categories/GetCategories?categoryIds=1&categoryIds=2&categoryIds=3&categoryIds=4

How to find where javaw.exe is installed?

Open a cmd shell,

cd \\
dir javaw.exe /s

Is there a C# case insensitive equals operator?

string.Equals(StringA, StringB, StringComparison.CurrentCultureIgnoreCase);

Remove the newline character in a list read from a file

str.strip() returns a string with leading+trailing whitespace removed, .lstrip and .rstrip for only leading and trailing respectively.


how to reference a YAML "setting" from elsewhere in the same YAML file?

Yes, using custom tags. Example in Python, making the !join tag join strings in an array:

import yaml

## define custom tag handler
def join(loader, node):
    seq = loader.construct_sequence(node)
    return ''.join([str(i) for i in seq])

## register the tag handler
yaml.add_constructor('!join', join)

## using your sample data
    root: &BASE /path/to/root/
    patha: !join [*BASE, a]
    pathb: !join [*BASE, b]
    pathc: !join [*BASE, c]

Which results in:

    'paths': {
        'patha': '/path/to/root/a',
        'pathb': '/path/to/root/b',
        'pathc': '/path/to/root/c',
        'root': '/path/to/root/'

The array of arguments to !join can have any number of elements of any data type, as long as they can be converted to string, so !join [*a, "/", *b, "/", *c] does what you would expect.

Get last key-value pair in PHP array

As the key is needed, the accepted solution doesn't work.


return array(key($array) => array_pop($array));

will return exactly as the example in the question.

Java: object to byte[] and byte[] to object converter (for Tokyo Cabinet)

You can look at how Hector does this for Cassandra, where the goal is the same - convert everything to and from byte[] in order to store/retrieve from a NoSQL database - see here. For the primitive types (+String), there are special Serializers, otherwise there is the generic ObjectSerializer (expecting Serializable, and using ObjectOutputStream). You can, of course, use only it for everything, but there might be redundant meta-data in the serialized form.

I guess you can copy the entire package and make use of it.

IE8 issue with Twitter Bootstrap 3

From the explanation it says that IE8 is the standard version for you and making content="IE=edge" will render the page in the highest mode. To make it compatible change it to content="IE=8".

IE8 mode supports many established standards, including the W3C Cascading Style Sheets Level 2.1 Specification and the W3C Selectors API; it also provides limited support for the W3C Cascading Style Sheets Level 3 Specification (Working Draft) and other emerging standards.

Edge mode tells Internet Explorer to display content in the highest mode available. With Internet Explorer 9, this is equivalent to IE9 mode. If a future release of Internet Explorer supported a higher compatibility mode, pages set to edge mode would appear in the highest mode supported by that version. Those same pages would still appear in IE9 mode when viewed with Internet Explorer 9.

Reference What does <meta http-equiv="X-UA-Compatible" content="IE=edge"> do?