Programs & Examples On #Mips

MIPS is a RISC instruction set architecture (ISA). It is commonly used in embedded devices such as set top boxes and networking gear. Many university-level computer architecture classes use the MIPS ISA due to its relative simplicity.

MIPS: Integer Multiplication and Division

To multiply, use mult for signed multiplication and multu for unsigned multiplication. Note that the result of the multiplication of two 32-bit numbers yields a 64-number. If you want the result back in $v0 that means that you assume the result will fit in 32 bits.

The 32 most significant bits will be held in the HI special register (accessible by mfhi instruction) and the 32 least significant bits will be held in the LO special register (accessible by the mflo instruction):


li $a0, 5
li $a1, 3
mult $a0, $a1
mfhi $a2 # 32 most significant bits of multiplication to $a2
mflo $v0 # 32 least significant bits of multiplication to $v0

To divide, use div for signed division and divu for unsigned division. In this case, the HI special register will hold the remainder and the LO special register will hold the quotient of the division.


div $a0, $a1
mfhi $a2 # remainder to $a2
mflo $v0 # quotient to $v0

Error "gnu/stubs-32.h: No such file or directory" while compiling Nachos source code

From the GNU UPC website:

Compiler build fails with fatal error: gnu/stubs-32.h: No such file or directory

This error message shows up on the 64 bit systems where GCC/UPC multilib feature is enabled, and it indicates that 32 bit version of libc is not installed. There are two ways to correct this problem:

  • Install 32 bit version of glibc (e.g. glibc-devel.i686 on Fedora, CentOS, ..)
  • Disable 'multilib' build by supplying "--disable-multilib" switch on the compiler configuration command

Mips how to store user input string

# This code works fine in QtSpim simulator

    buffer: .space 20
    str1:  .asciiz "Enter string"
    str2:  .asciiz "You wrote:\n"


    la $a0, str1    # Load and print string asking for string
    li $v0, 4

    li $v0, 8       # take in input

    la $a0, buffer  # load byte space into address
    li $a1, 20      # allot the byte space for string

    move $t0, $a0   # save string to t0

    la $a0, str2    # load and print "you wrote" string
    li $v0, 4

    la $a0, buffer  # reload byte space to primary address
    move $a0, $t0   # primary address = t0 address (load pointer)
    li $v0, 4       # print string

    li $v0, 10      # end program

Difference between "move" and "li" in MIPS assembly language

The move instruction copies a value from one register to another. The li instruction loads a specific numeric value into that register.

For the specific case of zero, you can use either the constant zero or the zero register to get that:

move $s0, $zero
li   $s0, 0

There's no register that generates a value other than zero, though, so you'd have to use li if you wanted some other number, like:

li $s0, 12345678

How to Calculate Jump Target Address and Branch Target Address?

(In the diagrams and text below, PC is the address of the branch instruction itself. PC+4 is the end of the branch instruction itself, and the start of the branch delay slot. Except in the absolute jump diagram.)

1. Branch Address Calculation

In MIPS branch instruction has only 16 bits offset to determine next instruction. We need a register added to this 16 bit value to determine next instruction and this register is actually implied by architecture. It is PC register since PC gets updated (PC+4) during the fetch cycle so that it holds the address of the next instruction.

We also limit the branch distance to -2^15 to +2^15 - 1 instruction from the (instruction after the) branch instruction. However, this is not real issue since most branches are local anyway.

So step by step :

  • Sign extend the 16 bit offset value to preserve its value.
  • Multiply resulting value with 4. The reason behind this is that If we are going to branch some address, and PC is already word aligned, then the immediate value has to be word-aligned as well. However, it makes no sense to make the immediate word-aligned because we would be wasting low two bits by forcing them to be 00.
  • Now we have a 32 bit relative offset. Add this value to PC + 4 and that is your branch address.

Branch address calculation

2. Jump Address Calculation

For Jump instruction MIPS has only 26 bits to determine Jump location. Jumps are relative to PC in MIPS. Like branch, immediate jump value needs to be word-aligned; therefore, we need to multiply 26 bit address with four.

Again step by step:

  • Multiply 26 bit value with 4.
  • Since we are jumping relative to PC+4 value, concatenate first four bits of PC+4 value to left of our jump address.
  • Resulting address is the jump value.

In other words, replace the lower 28 bits of the PC + 4 with the lower 26 bits of the fetched instruction shifted left by 2 bits.

enter image description here

Jumps are region-relative to the branch-delay slot, not necessarily the branch itself. In the diagram above, PC has already advanced to the branch delay slot before the jump calculation. (In a classic-RISC 5 stage pipeline, the BD was fetched in the same cycle the jump is decoded, so that PC+4 next instruction address is already available for jumps as well as branches, and calculating relative to the jump's own address would have required extra work to save that address.)

Source: Bilkent University CS 224 Course Slides

How do I import a specific version of a package using go get?

Go 1.11 will have a feature called go modules and you can simply add a dependency with a version. Follow these steps:

go mod init .
go mod edit -require[email protected]
go get -v -t ./...   
go build
go install 

Here's more info on that topic -

How to resolve javax.mail.AuthenticationFailedException issue?

You need to implement a custom Authenticator

import javax.mail.Authenticator;
import javax.mail.PasswordAuthentication;

class GMailAuthenticator extends Authenticator {
     String user;
     String pw;
     public GMailAuthenticator (String username, String password)
        this.user = username; = password;
    public PasswordAuthentication getPasswordAuthentication()
       return new PasswordAuthentication(user, pw);

Now use it in the Session

Session session = Session.getInstance(props, new GMailAuthenticator(username, password));

Also check out the JavaMail FAQ

Mock HttpContext.Current in Test Init Method

If your application third party redirect internally, so it is better to mock HttpContext in below way :

HttpWorkerRequest initWorkerRequest = new SimpleWorkerRequest("","","","",new StringWriter(CultureInfo.InvariantCulture));
System.Web.HttpContext.Current = new HttpContext(initWorkerRequest);
System.Web.HttpContext.Current.Request.Browser = new HttpBrowserCapabilities();
System.Web.HttpContext.Current.Request.Browser.Capabilities = new Dictionary<string, string> { { "requiresPostRedirectionHandling", "false" } };

"ImportError: no module named 'requests'" after installing with pip

Run in command prompt.

pip list

Check what version you have installed on your system if you have an old version.

Try to uninstall the package...

pip uninstall requests

Try after to install it:

pip install requests

You can also test if pip does not do the job.

easy_install requests

Spring Maven clean error - The requested profile "pom.xml" could not be activated because it does not exist

The warning message

[WARNING] The requested profile "pom.xml" could not be activated because it does not exist.

means that you somehow passed -P pom.xml to Maven which means "there is a profile called pom.xml; find it and activate it". Check your environment and your settings.xml for this flag and also look at all <profile> elements inside the various XML files.

Usually, mvn help:effective-pom is also useful to see what the real POM would look like.

Now the error means that you tried to configure Maven to build Java 8 code but you're not using a Java 8 runtime. Solutions:

  1. Install Java 8
  2. Make sure Maven uses Java 8 if you have it installed. JAVA_HOME is your friend
  3. Configure the Java compiler in your pom.xml to a Java version which you actually have.


Install / upgrade gradle on Mac OS X

Another alternative is to use sdkman. An advantage of sdkman over brew is that many versions of gradle are supported. (brew only supports the latest version and 2.14.) To install sdkman execute:

curl -s "" | bash

Then follow the instructions. Go here for more installation information. Once sdkman is installed use the command:

sdk install gradle

Or to install a specific version:

sdk install gradle 2.2

Or use to use a specific installed version:

sdk use gradle 2.2

To see which versions are installed and available:

sdk list gradle

For more information go here.

500 internal server error at GetResponse()

looking at your error message first of all I would suggest you to recompile your whole application, make sure all the required dlls are there in bin folder when you recompile it.

How to check if an int is a null

A primitive int cannot be null. If you need null, use Integer instead.

What is the difference between using constructor vs getInitialState in React / React Native?

Constructor The constructor is a method that's automatically called during the creation of an object from a class. ... Simply put, the constructor aids in constructing things. In React, the constructor is no different. It can be used to bind event handlers to the component and/or initializing the local state of the component.Jan 23, 2019

getInitialState In ES6 classes, you can define the initial state by assigning this.state in the constructor:

Look at this example

var Counter = createReactClass({
  getInitialState: function() {
    return {count: this.props.initialCount};
  // ...

With createReactClass(), you have to provide a separate getInitialState method that returns the initial state:

JavaScript Number Split into individual digits

I am posting this answer to introduce the use of unshift which is a modern solution. With push, you add to the end of an array while unshift adds to the beginning. This makes the mathematical approach more powerful as you won't need to reverse anymore.

let num = 278;
let digits = [];
while (num > 0) {
    digits.unshift(num % 10);
    num = parseInt(num / 10);

AngularJS: How to make angular load script inside ng-include?

Unfortunately all the answers in this post didn't work for me. I kept getting following error.

Failed to execute 'write' on 'Document': It isn't possible to write into a document from an asynchronously-loaded external script unless it is explicitly opened.

I found out that this happens if you use some 3rd party widgets (demandforce in my case) that also call additional external JavaScript files and try to insert HTML. Looking at the console and the JavaScript code, I noticed multiple lines like this:

document.write("<script type='text/javascript' "..."'></script>");

I used 3rd party JavaScript files (htmlParser.js and postscribe.js) from: That solved the problem in this post and fixed the above error at the same time.

(This was a quick and dirty way around under the tight deadline I have now. I am not comfortable with using 3rd party JavaScript library however. I hope someone can come up with a cleaner and better way.)

Creating lowpass filter in SciPy - understanding methods and units

A few comments:

  • The Nyquist frequency is half the sampling rate.
  • You are working with regularly sampled data, so you want a digital filter, not an analog filter. This means you should not use analog=True in the call to butter, and you should use scipy.signal.freqz (not freqs) to generate the frequency response.
  • One goal of those short utility functions is to allow you to leave all your frequencies expressed in Hz. You shouldn't have to convert to rad/sec. As long as you express your frequencies with consistent units, the scaling in the utility functions takes care of the normalization for you.

Here's my modified version of your script, followed by the plot that it generates.

import numpy as np
from scipy.signal import butter, lfilter, freqz
import matplotlib.pyplot as plt

def butter_lowpass(cutoff, fs, order=5):
    nyq = 0.5 * fs
    normal_cutoff = cutoff / nyq
    b, a = butter(order, normal_cutoff, btype='low', analog=False)
    return b, a

def butter_lowpass_filter(data, cutoff, fs, order=5):
    b, a = butter_lowpass(cutoff, fs, order=order)
    y = lfilter(b, a, data)
    return y

# Filter requirements.
order = 6
fs = 30.0       # sample rate, Hz
cutoff = 3.667  # desired cutoff frequency of the filter, Hz

# Get the filter coefficients so we can check its frequency response.
b, a = butter_lowpass(cutoff, fs, order)

# Plot the frequency response.
w, h = freqz(b, a, worN=8000)
plt.subplot(2, 1, 1)
plt.plot(0.5*fs*w/np.pi, np.abs(h), 'b')
plt.plot(cutoff, 0.5*np.sqrt(2), 'ko')
plt.axvline(cutoff, color='k')
plt.xlim(0, 0.5*fs)
plt.title("Lowpass Filter Frequency Response")
plt.xlabel('Frequency [Hz]')

# Demonstrate the use of the filter.
# First make some data to be filtered.
T = 5.0         # seconds
n = int(T * fs) # total number of samples
t = np.linspace(0, T, n, endpoint=False)
# "Noisy" data.  We want to recover the 1.2 Hz signal from this.
data = np.sin(1.2*2*np.pi*t) + 1.5*np.cos(9*2*np.pi*t) + 0.5*np.sin(12.0*2*np.pi*t)

# Filter the data, and plot both the original and filtered signals.
y = butter_lowpass_filter(data, cutoff, fs, order)

plt.subplot(2, 1, 2)
plt.plot(t, data, 'b-', label='data')
plt.plot(t, y, 'g-', linewidth=2, label='filtered data')
plt.xlabel('Time [sec]')


lowpass example

Width of input type=text element

input width is 10 + 2 times 1 px for border

How can I get the day of a specific date with PHP

$date = '2009-10-22';
$sepparator = '-';
$parts = explode($sepparator, $date);
$dayForDate = date("l", mktime(0, 0, 0, $parts[1], $parts[2], $parts[0]));

PHPExcel How to apply styles and set cell width and cell height to cell generated dynamically

You can use


or define auto-size:


How to execute Table valued function

You can execute it just as you select a table using SELECT clause. In addition you can provide parameters within parentheses.

Try with below syntax:

SELECT * FROM yourFunctionName(parameter1, parameter2)

Git: Recover deleted (remote) branch

I think that you have a mismatched config for 'fetch' and 'push' so this has caused default fetch/push to not round trip properly. Fortunately you have fetched the branches that you subsequently deleted so you should be able to recreate them with an explicit push.

git push origin origin/contact_page:contact_page origin/new_pictures:new_pictures

How to install an APK file on an Android phone?

If you have access to a Gmail account on the phone then an easy way (in terms of minimal set up effort) is to mail the .apk file to that Gmail account.

If you then access that account from the native Gmail app on the phone it recognises that the attachment is an app and offers an "Install" button.

As per other responses this approach also requires that you have selected USB debugging on the device.

Try this - it is remarkably easy ;-)

Reading specific columns from a text file in python

for x in lines:
    result.append(x.split(' ')[1])

You can do the same using a list comprehension

print([x.split(' ')[1] for x in open(file).readlines()])

Docs on split()

string.split(s[, sep[, maxsplit]])

Return a list of the words of the string s. If the optional second argument sep is absent or None, the words are separated by arbitrary strings of whitespace characters (space, tab, newline, return, formfeed). If the second argument sep is present and not None, it specifies a string to be used as the word separator. The returned list will then have one more item than the number of non-overlapping occurrences of the separator in the string.

So, you can omit the space I used and do just x.split() but this will also remove tabs and newlines, be aware of that.

How to find the width of a div using vanilla JavaScript?

You can use clientWidth or offsetWidth Mozilla developer network reference

It would be like:

document.getElementById("yourDiv").clientWidth; // returns number, like 728

or with borders width :

document.getElementById("yourDiv").offsetWidth; // 728 + borders width

How to iterate through a list of objects in C++

It is also worth to mention, that if you DO NOT intent to modify the values of the list, it is possible (and better) to use the const_iterator, as follows:

for (std::list<Student>::const_iterator it = data.begin(); it != data.end(); ++it){
    // do whatever you wish but don't modify the list elements
    std::cout << it->name;

How to configure SSL certificates with Charles Web Proxy and the latest Android Emulator on Windows?

What worked for me - should really be moved to iPhone:


  1. Enable transparent Http proxying
  2. Enable SSL proxying
  3. Right click on incoming request and select SSL proxying


  1. Download Charles CA Certificate bundle
  2. Email yourself charles-proxy-ssl-proxying-certificate.crt


  1. Enable http proxy for Charles on port 8888
  2. Select and install email attachment, yes trust it!

Voila, you can now view encrypted traffic from the domain added in the SSL proxying

Garbage collector in Android

Quick note for Xamarin developers.

If you would like to call System.gc() in Xamarin.Android apps you should call Java.Lang.JavaSystem.Gc()

HTML table with 100% width, with vertical scroll inside tbody

In following solution, table occupies 100% of the parent container, no absolute sizes required. It's pure CSS, flex layout is used.

Here is how it looks: enter image description here

Possible disadvantages:

  • vertical scrollbar is always visible, regardless of whether it's required;
  • table layout is fixed - columns do not resize according to the content width (you still can set whatever column width you want explicitly);
  • there is one absolute size - the width of the scrollbar, which is about 0.9em for the browsers I was able to check.

HTML (shortened):

<div class="table-container">

CSS, with some decorations omitted for clarity:

.table-container {
    height: 10em;
table {
    display: flex;
    flex-flow: column;
    height: 100%;
    width: 100%;
table thead {
    /* head takes the height it requires, 
    and it's not scaled when table is resized */
    flex: 0 0 auto;
    width: calc(100% - 0.9em);
table tbody {
    /* body takes all the remaining available space */
    flex: 1 1 auto;
    display: block;
    overflow-y: scroll;
table tbody tr {
    width: 100%;
table thead, table tbody tr {
    display: table;
    table-layout: fixed;

full code on jsfiddle

Same code in LESS so you can mix it in:

.table-scrollable() {
  @scrollbar-width: 0.9em;
  display: flex;
  flex-flow: column;

  tbody tr {
    display: table;
    table-layout: fixed;

  thead {
    flex: 0 0 auto;
    width: ~"calc(100% - @{scrollbar-width})";

  tbody {
    display: block;
    flex: 1 1 auto;
    overflow-y: scroll;

    tr {
      width: 100%;

Test if a string contains any of the strings from an array

We can also do like this:

if (string.matches("^.*?((?i)item1|item2|item3).*$"))
(?i): used for case insensitive
.*? & .*$: used for checking whether it is present anywhere in between the string.

Selecting a row of pandas series/dataframe by integer index

To index-based access to the pandas table, one can also consider numpy.as_array option to convert the table to Numpy array as

np_df = df.as_matrix()

and then


would work.

How to check if the given string is palindrome?

Const-correct C/C++ pointer solution. Minimal operations in loop.

int IsPalindrome (const char *str)
    const unsigned len = strlen(str);
    const char *end = &str[len-1];
    while (str < end)
        if (*str++ != *end--)
            return 0;
    return 1;

Fetching data from MySQL database using PHP, Displaying it in a form for editing

 include 'cdb.php';
$show=mysqli_query( $conn,"SELECT *FROM 'reg'");

while($row1= mysqli_fetch_array($show)) 


                $Name= $row1['name'];
                $email = $row1['email'];
                $username = $row1['username'];
                $password= $row1['password'];
                $birthm = $row1['bmonth'];
                $birthd= $row1['bday'];
                $birthy= $row1['byear'];
                $gernder = $row1['gender'];
                $phone= $row1['phone'];




<table border="-2" bgcolor="pink" style="width: 12px; height: 100px;" >

    id<input type="text" name="" style="width: 30px;" value= "<?php echo $row1['id']; ?>"  >



 name <input type="text" name=""  style="width: 60px;" value= "<?php echo $row1['Name']; ?>" >

 email<input type="text" name="" style="width: 60px;" value= "<?php echo $row1['email']; ?>"  >
    username<input type="hidden" name="" style="width: 60px;"  value= "<?php echo $username['email']; ?>" >
    password<input type="hidden" name="" style="width: 60px;"  value= "<?php echo $row1['password']; ?>">

    birthday month<input type="text" name="" style="width: 60px;"  value= "<?php echo $row1['birthm']; ?>">
   birthday day<input type="text" name="" style="width: 60px;"  value= "<?php echo $row1['birthd']; ?>">
       birthday year<input type="text" name="" style="width: 60px;" value= "<?php echo $row1['birthy']; ?>" >
    gender<input type="text" name="" style="width: 60px;" value= "<?php echo $row1['gender']; ?>">
    phone number<input type="text" name="" style="width: 60px;" value= "<?php echo $row1['phone']; ?>">
     image<input type="text" name="" style="width: 60px;"  value= "<?php echo $row1['image']; ?>">


<font color="pink"> <a href="update.php">update</a></font>



How to make Twitter bootstrap modal full screen

I've came up with a "responsive" solution for fullscreen modals:

Fullscreen Modals that can be enabled only on certain breakpoints. In this way the modal will display "normal" on wider (desktop) screens and fullscreen on smaller (tablet or mobile) screens, giving it the feeling of a native app.

Implemented for Bootstrap 3 and Bootstrap 4. Included by default in Bootstrap 5.

Bootstrap v5

Fullscreen modals are included by default in Bootstrap 5:

Bootstrap v4

The following generic code should work:

.modal {
  padding: 0 !important; // override inline padding-right added from js
.modal .modal-dialog {
  width: 100%;
  max-width: none;
  height: 100%;
  margin: 0;
.modal .modal-content {
  height: 100%;
  border: 0;
  border-radius: 0;
.modal .modal-body {
  overflow-y: auto;

By including the scss code below, it generates the following classes that need to be added to the .modal element:

|               |   xs    |   sm    |   md    |   lg    |   xl    | 
|               | <576px  | =576px  | =768px  | =992px  | =1200px |
|.fullscreen    |  100%   | default | default | default | default | 
|.fullscreen-sm |  100%   |  100%   | default | default | default | 
|.fullscreen-md |  100%   |  100%   |  100%   | default | default |
|.fullscreen-lg |  100%   |  100%   |  100%   |  100%   | default |
|.fullscreen-xl |  100%   |  100%   |  100%   |  100%   |  100%   |

The scss code is:

@mixin modal-fullscreen() {
  padding: 0 !important; // override inline padding-right added from js

  .modal-dialog {
    width: 100%;
    max-width: none;
    height: 100%;
    margin: 0;

  .modal-content {
    height: 100%;
    border: 0;
    border-radius: 0;

  .modal-body {
    overflow-y: auto;


@each $breakpoint in map-keys($grid-breakpoints) {
  @include media-breakpoint-down($breakpoint) {
    $infix: breakpoint-infix($breakpoint, $grid-breakpoints);

    .modal-fullscreen#{$infix} {
      @include modal-fullscreen();

Demo on Codepen:

Bootstrap v3

Based on previous responses to this topic (@Chris J, @kkarli), the following generic code should work:

.modal {
  padding: 0 !important; // override inline padding-right added from js

.modal .modal-dialog {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;

.modal .modal-content {
  height: auto;
  min-height: 100%;
  border: 0 none;
  border-radius: 0;
  box-shadow: none;

If you want to use responsive fullscreen modals, use the following classes that need to be added to .modal element:

  • .modal-fullscreen-md-down - the modal is fullscreen for screens smaller than 1200px.
  • .modal-fullscreen-sm-down - the modal is fullscreen for screens smaller than 922px.
  • .modal-fullscreen-xs-down - the modal is fullscreen for screen smaller than 768px.

Take a look at the following code:

/* Extra small devices (less than 768px) */
@media (max-width: 767px) {
  .modal-fullscreen-xs-down {
    padding: 0 !important;
  .modal-fullscreen-xs-down .modal-dialog {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
  .modal-fullscreen-xs-down .modal-content {
    height: auto;
    min-height: 100%;
    border: 0 none;
    border-radius: 0;
    box-shadow: none;

/* Small devices (less than 992px) */
@media (max-width: 991px) {
  .modal-fullscreen-sm-down {
    padding: 0 !important;
  .modal-fullscreen-sm-down .modal-dialog {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
  .modal-fullscreen-sm-down .modal-content {
    height: auto;
    min-height: 100%;
    border: 0 none;
    border-radius: 0;
    box-shadow: none;

/* Medium devices (less than 1200px) */
@media (max-width: 1199px) {
  .modal-fullscreen-md-down {
    padding: 0 !important;
  .modal-fullscreen-md-down .modal-dialog {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
  .modal-fullscreen-md-down .modal-content {
    height: auto;
    min-height: 100%;
    border: 0 none;
    border-radius: 0;
    box-shadow: none;

Demo is available on Codepen:

Those who use Sass as a preprocessor can take advantage of the following mixin:

@mixin modal-fullscreen() {
  padding: 0 !important; // override inline padding-right added from js

  .modal-dialog {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;

  .modal-content {
    height: auto;
    min-height: 100%;
    border: 0 none;
    border-radius: 0;
    box-shadow: none;


Are string.Equals() and == operator really same?

Two differences:

  • Equals is polymorphic (i.e. it can be overridden, and the implementation used will depend on the execution-time type of the target object), whereas the implementation of == used is determined based on the compile-time types of the objects:

    // Avoid getting confused by interning
    object x = new StringBuilder("hello").ToString();
    object y = new StringBuilder("hello").ToString();
    if (x.Equals(y)) // Yes
    // The compiler doesn't know to call ==(string, string) so it generates
    // a reference comparision instead
    if (x == y) // No
    string xs = (string) x;
    string ys = (string) y;
    // Now *this* will call ==(string, string), comparing values appropriately
    if (xs == ys) // Yes
  • Equals will go bang if you call it on null, == won't

    string x = null;
    string y = null;
    if (x.Equals(y)) // Bang
    if (x == y) // Yes

Note that you can avoid the latter being a problem using object.Equals:

if (object.Equals(x, y)) // Fine even if x or y is null

Twitter Bootstrap carousel different height images cause bouncing arrows

This jQuery function worked best for me. I'm using bootstrap 4 within a WordPress theme and I've used the full jQuery instead of jQuery slim.

// Set all carousel items to the same height
function carouselNormalization() {

    window.heights = [], //create empty array to store height values
    window.tallest; //create variable to make note of the tallest slide

    function normalizeHeights() {
        jQuery('#latest-blog-posts .carousel-item').each(function() { //add heights to array
        window.tallest = Math.max.apply(null, window.heights); //cache largest value
        jQuery('#latest-blog-posts .carousel-item').each(function() {
            jQuery(this).css('min-height',tallest + 'px');

    jQuery(window).on('resize orientationchange', function () {

        window.tallest = 0, window.heights.length = 0; //reset vars
        jQuery('.sc_slides .item').each(function() {
            jQuery(this).css('min-height','0'); //reset min-height

        normalizeHeights(); //run it again 



jQuery( document ).ready(function() {


Linux command-line call not returning what it should from os.system?

The simplest way is like this:

import os
retvalue = os.popen("ps -p 2993 -o time --no-headers").readlines()
print retvalue

This will be returned as a list

How to store image in SQL Server database tables column

Insert Into FEMALE(ID, Image)
Select '1', BulkColumn 
from Openrowset (Bulk 'D:\thepathofimage.jpg', Single_Blob) as Image

You will also need admin rights to run the query.

String's Maximum length in Java - calling length() method

Since arrays must be indexed with integers, the maximum length of an array is Integer.MAX_INT (231-1, or 2 147 483 647). This is assuming you have enough memory to hold an array of that size, of course.

Get size of a View in React Native

Maybe you can use measure:

measureProgressBar() {

logProgressBarLayout(ox, oy, width, height, px, py) {
  console.log("ox: " + ox);
  console.log("oy: " + oy);
  console.log("width: " + width);
  console.log("height: " + height);
  console.log("px: " + px);
  console.log("py: " + py);

When should I use semicolons in SQL Server?

I still have a lot to learn about T-SQL, but in working up some code for a transaction (and basing code on examples from stackoverflow and other sites) I found a case where it seems a semicolon is required and if it is missing, the statement does not seem to execute at all and no error is raised. This doesn't seem to be covered in any of the above answers. (This was using MS SQL Server 2012.)

Once I had the transaction working the way I wanted, I decided to put a try-catch around it so if there are any errors it gets rolled back. Only after doing this, the transaction was not committed (SSMS confirms this when trying to close the window with a nice message alerting you to the fact that there is an uncommitted transaction.

So this


outside a BEGIN TRY/END TRY block worked fine to commit the transaction, but inside the block it had to be


Note there is no error or warning provided and no indication that the transaction is still uncommitted until attempting to close the query tab.

Fortunately this causes such a huge problem that it is immediately obvious that there is a problem. Unfortunately since no error (syntax or otherwise) is reported it was not immediately obvious what the problem was.

Contrary-wise, ROLLBACK TRANSACTION seems to work equally well in the BEGIN CATCH block with or without a semicolon.

There may be some logic to this but it feels arbitrary and Alice-in-Wonderland-ish.

Java 8 - Best way to transform a list: map or foreach?

I agree with the existing answers that the second form is better because it does not have any side effects and is easier to parallelise (just use a parallel stream).

Performance wise, it appears they are equivalent until you start using parallel streams. In that case, map will perform really much better. See below the micro benchmark results:

Benchmark                         Mode  Samples    Score   Error  Units
SO28319064.forEach                avgt      100  187.310 ± 1.768  ms/op                    avgt      100  189.180 ± 1.692  ms/op
SO28319064.mapWithParallelStream  avgt      100   55,577 ± 0,782  ms/op

You can't boost the first example in the same manner because forEach is a terminal method - it returns void - so you are forced to use a stateful lambda. But that is really a bad idea if you are using parallel streams.

Finally note that your second snippet can be written in a sligthly more concise way with method references and static imports:

myFinalList =

mssql convert varchar to float

DECLARE @INPUT VARCHAR(5) = '0.12',@INPUT_1 VARCHAR(5)='0.12x';
select CONVERT(float, @INPUT) YOUR_QUERY ,
case when isnumeric(@INPUT_1)=1 THEN CONVERT(float, @INPUT_1) ELSE 0 END AS YOUR_QUERY_ANSWERED

above will return values

however below query wont work

DECLARE @INPUT VARCHAR(5) = '0.12',@INPUT_1 VARCHAR(5)='0.12x';
select CONVERT(float, @INPUT) YOUR_QUERY ,
case when isnumeric(@INPUT_1)=1 THEN CONVERT(float, @INPUT_1) ELSE **@INPUT_1** END AS YOUR_QUERY_ANSWERED

as @INPUT_1 actually has varchar in it.

So your output column must have a varchar in it.

XPath to select Element by attribute value

You need to remove the / before the [. Predicates (the parts in [ ]) shouldn't have slashes immediately before them. Also, to select the Employee element itself, you should leave off the /text() at the end or otherwise you'd just be selecting the whitespace text values immediately under the Employee element.


Edit: As Jens points out in the comments, // can be very slow because it searches the entire document for matching nodes. If the structure of the documents you're working with is going to be consistent, you are probably best off using a full path, for example:


Datepicker: How to popup datepicker when click on edittext

public class DatePickerActivity extends AppCompatActivity {
    Button button;
    static TextView textView;

    protected void onCreate(Bundle savedInstanceState) {
        button= (Button) findViewById(;
        textView= (TextView) findViewById(;

        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                DialogFragment newFragment=new DatePickerFragment();
      , "datepicker");


    public class DatePickerFragment extends DialogFragment implements    DatePickerDialog.OnDateSetListener{
        public void onDateSet(DatePicker view, int year, int monthOfYear, int  day) {
            String years=""+year;
            String months=""+(monthOfYear+1);
            String days=""+day;
            if(monthOfYear>=0 && monthOfYear<9){
            if(day>0 && day<10){



        public Dialog onCreateDialog(Bundle savedInstanceState) {
            //use the current date as the default date in the picker
            final Calendar c=Calendar.getInstance();
            int year=c.get(Calendar.YEAR);
            int month=c.get(Calendar.MONTH);
            int day=c.get(Calendar.DAY_OF_MONTH);
            DatePickerDialog datePickerDialog=null;
            datePickerDialog=new DatePickerDialog(getActivity(), this, year,  month, day);

            return datePickerDialog;



clearing select using jquery

If you don't care about any child elements, e.g. optgroup, you can use empty()...


Otherwise, if you only want option elements removed, use remove().

$('select option').remove();

Android Facebook 4.0 SDK How to get Email, Date of Birth and gender of User

You won't get Profile in onSuccess() you need to implement ProfileTracker along with registering callback

mProfileTracker = new ProfileTracker() {
    protected void onCurrentProfileChanged(Profile oldProfile, Profile newProfile) {
        // Fetch user details from New Profile

Also don't forget to handle the start and stop of profile tracker

Now you will have a profile to get AccessToken from (solved the issue of null profile). You just have to use "" to get any data.

Check if a file exists locally using JavaScript only

An alternative: you can use a "hidden" applet element which implements this exist-check using a privileged action object and override your run method by:

File file = new File(yourPath);
return file.exists();

Handling multiple IDs in jQuery

Yes, #id selectors combined with a multiple selector (comma) is perfectly valid in both jQuery and CSS.

However, for your example, since <script> comes before the elements, you need a document.ready handler, so it waits until the elements are in the DOM to go looking for them, like this:

  $(function() {

<div id="segement1"></div>
<div id="segement2"></div>
<div id="segement3"></div>

Is there a command like "watch" or "inotifywait" on the Mac?

I have a GIST for this and the usage is pretty simple

watchfiles <cmd> <paths...>

To illustrate, the following command will echo Hello World every time that file1 OR file2 change; and the default interval check is 1 second

watchfiles 'echo Hello World' /path/to/file1 /path/to/file2 

If I want to check every 5 seconds I can use the -t flag

watchfiles -t 'echo Hello World' /path/to/file1 /path/to/file2 
  • -v enables the verbose mode which shows debug information
  • -q makes watchfiles execute quietly (# will be shown so the user can see the program is executing)
  • -qq makes watchfiles execute completely quietly
  • -h shows the help and usage

java.lang.ClassNotFoundException: org.apache.jsp.index_jsp

It's been a while since I posted this, but I thought I would show how I figured it out (as best as I recall now).

I did a Maven dependency tree to find dependency conflicts, and I removed all conflicts with exclusions in dependencies, e.g.:


Also, I used the provided scope for javax.servlet dependencies so as not to introduce an additional conflict with what is provided by Tomcat when I run the app.



Set space between divs

For folks searching for solution to set spacing between N divs, here is another approach using pseudo selectors:

div:not(:last-child) {
  margin-right: 40px;

You can also combine child pseudo selectors:

div:not(:first-child):not(:last-child) {
  margin-left: 20px;
  margin-right: 20px;

How to Edit a row in the datatable

First you need to find a row with id == 2 then change the name so:

foreach(DataRow dr in table.Rows) // search whole table
    if(dr["Product_id"] == 2) // if id==2
        dr["Product_name"] = "cde"; //change the name
        //break; break or not depending on you

You could also try these solutions:

table.Rows[1]["Product_name"] = "cde" // not recommended as it selects 2nd row as I know that it has id 2


DataRow dr = table.Select("Product_id=2").FirstOrDefault(); // finds all rows with id==2 and selects first or null if haven't found any
if(dr != null)
    dr["Product_name"] = "cde"; //changes the Product_name

Python: Total sum of a list of numbers with the for loop

l = [1,2,3,4,5]
sum = 0
for x in l:
    sum = sum + x

And you can change l for any list you want.

Best way to generate xml?

Use lxml.builder class, from:

import lxml.builder as lb
from lxml import etree

nstext = "new story"
story = lb.E.Asset(
  lb.E.Attribute(nstext, name="Name", act="set"),
            name="Scope", act="set")

print 'story:\n', etree.tostring(story, pretty_print=True)


  <Attribute name="Name" act="set">new story</Attribute>
  <Relation name="Scope" act="set">
    <Asset idref="Scope:767"/>

How do I execute a stored procedure once for each row returned by query?

try to change your method if you need to loop!

within the parent stored procedure, create a #temp table that contains the data that you need to process. Call the child stored procedure, the #temp table will be visible and you can process it, hopefully working with the entire set of data and without a cursor or loop.

this really depends on what this child stored procedure is doing. If you are UPDATE-ing, you can "update from" joining in the #temp table and do all the work in one statement without a loop. The same can be done for INSERT and DELETEs. If you need to do multiple updates with IFs you can convert those to multiple UPDATE FROM with the #temp table and use CASE statements or WHERE conditions.

When working in a database try to lose the mindset of looping, it is a real performance drain, will cause locking/blocking and slow down the processing. If you loop everywhere, your system will not scale very well, and will be very hard to speed up when users start complaining about slow refreshes.

Post the content of this procedure you want call in a loop, and I'll bet 9 out of 10 times, you could write it to work on a set of rows.

What do we mean by Byte array?

A byte is 8 bits (binary data).

A byte array is an array of bytes (tautology FTW!).

You could use a byte array to store a collection of binary data, for example, the contents of a file. The downside to this is that the entire file contents must be loaded into memory.

For large amounts of binary data, it would be better to use a streaming data type if your language supports it.

Run Jquery function on window events: load, resize, and scroll?

just call your function inside the events.


$(document).ready(function(){  // or  $(window).load(function(){


$(window).resize(function () {


$(window).scroll(function () {

or bind all event in one function

$(window).on("load scroll resize",function(e){

Resolve promises one after another (i.e. in sequence)?

My answer based on

Promise.series = function series(arrayOfPromises) {
    var results = [];
    return arrayOfPromises.reduce(function(seriesPromise, promise) {
      return seriesPromise.then(function() {
        return promise
        .then(function(result) {
    }, Promise.resolve())
    .then(function() {
      return results;

This solution returns the results as an array like Promise.all().


Promise.series([array of promises])
.then(function(results) { 
  // do stuff with results here

Angular 1 - get current URL parameters

To get parameters from URL with ngRoute . It means that you will need to include angular-route.js in your application as a dependency. More information how to do this on official ngRoute documentation.

The solution for the question:

// You need to add 'ngRoute' as a dependency in your app
angular.module('ngApp', ['ngRoute'])
    .config(function ($routeProvider, $locationProvider) {
        // configure the routing rules here
        $routeProvider.when('/backend/:type/:id', {
            controller: 'PagesCtrl'

        // enable HTML5mode to disable hashbang urls
    .controller('PagesCtrl', function ($routeParams) {
        console.log($, $routeParams.type);

If you don't enable the $locationProvider.html5Mode(true);. Urls will use hashbang(/#/).

More information about routing can be found on official angular $route API documentation.

Side note: This question is answering how to achieve this using ng-Route however I would recommend using the ui-Router for routing. It is more flexible, offers more functionality, the documentations is great and it is considered the best routing library for angular.

On Windows, running "import tensorflow" generates No module named "_pywrap_tensorflow" error

I have Win7 Pro 64-bit on AMD cpu, no gpu. I was following the instructions under "Installing with native pip" at The installation step went ok but the attempt to import tensorflow produced the infamous:

ImportError: No module named '_pywrap_tensorflow_internal'

This seems to be one of those situations where a lot of unrelated things can go wrong, depending on configuration, which all cascade through to the same error.

In my case, installing MSVCP140.DLL was the answer.

You have MSVCP140.DLL already if

  1. you have a file C:\Windows\System32\MSVCP140.DLL, AND
  2. if you have a 64 bit system, then you additionally have C:\Windows\SysWOW64\MSVCP140.DLL.

I installed it manually, which was unnecessary (the redistributable is not the whole Visual C++ development mess and isn't large). Use the link posted earlier in this thread to install it: Visual C++ 2015 redistributable.

Also, I recommend that you override the default install directory for Python and put it anywhere not under C:\Program Files, because Windows tries to write-protect files there, which causes problems later.

How do I determine whether my calculation of pi is accurate?

You could try computing sin(pi/2) (or cos(pi/2) for that matter) using the (fairly) quickly converging power series for sin and cos. (Even better: use various doubling formulas to compute nearer x=0 for faster convergence.)

BTW, better than using series for tan(x) is, with computing say cos(x) as a black box (e.g. you could use taylor series as above) is to do root finding via Newton. There certainly are better algorithms out there, but if you don't want to verify tons of digits this should suffice (and it's not that tricky to implement, and you only need a bit of calculus to understand why it works.)

Is there any difference between "!=" and "<>" in Oracle Sql?

Actually, there are four forms of this operator:


and even

¬= -- worked on some obscure platforms in the dark ages

which are the same, but treated differently when a verbatim match is required (stored outlines or cached queries).

How to convert int[] to Integer[] in Java?

Rather than write your own code you can use an IntBuffer to wrap the existing int[] without having to copy the data into an Integer array

int[] a = {1,2,3,4};
IntBuffer b = IntBuffer.wrap(a);

IntBuffer implements comparable so you are able to use the code you already have written. Formally maps compare keys such that a.equals(b) is used to say two keys are equal, so two IntBuffers with array 1,2,3 - even if the arrays are in different memory locations - are said to be equal and so will work for your frequency code.

ArrayList<int[]> data = ... // load a dataset`

Map<IntBuffer, Double> frequencies = new HashMap<IntBuffer, Double>();

for(int[] a : data) {

    IntBuffer q = IntBuffer.wrap(a);

    if(frequencies.containsKey(q)) {
        frequencies.put(q, tfs.get(q) + p);
    } else {
        frequencies.put(q, p);


Hope that helps

How to fix broken paste clipboard in VNC on Windows

Many times you must have observed that clipboard operations like copy/cut and paste suddenly stops workings with the vncviewer. The main reason for this there is a program called as vncconfig responsible for these clipboard transfers. Some times the program may get closed because of some bug in vnc or some other reasons like you closed that window.

To get those clipboard operations back you need to run the program "vncconfig &".

After this your clipboard actions should work fine with out any problems.

Run "vncconfig &" on the client.

How to manually set REFERER header in Javascript?

If you want to change the referer (url) header that will be sent to the server when a user clicks an anchor or iframe is opened, you can do it without any hacks. Simply do history.replaceState, you will change the url as it will appear in the browser bar and also the referer that will be send to the server.

How to check that a JCheckBox is checked?

By using itemStateChanged(ItemListener) you can track selecting and deselecting checkbox (and do whatever you want based on it):

myCheckBox.addItemListener(new ItemListener() {
    public void itemStateChanged(ItemEvent e) {
        if(e.getStateChange() == ItemEvent.SELECTED) {//checkbox has been selected
            //do something...
        } else {//checkbox has been deselected
            //do something...

Java Swing itemStateChanged docu should help too. By using isSelected() method you can just test if actual is checkbox selected:


SET NAMES utf8 in MySQL?

Getting encoding right is really tricky - there are too many layers:

  • Browser
  • Page
  • PHP
  • MySQL

The SQL command "SET CHARSET utf8" from PHP will ensure that the client side (PHP) will get the data in utf8, no matter how they are stored in the database. Of course, they need to be stored correctly first.

DDL definition vs. real data

Encoding defined for a table/column doesn't really mean that the data are in that encoding. If you happened to have a table defined as utf8 but stored as differtent encoding, then MySQL will treat them as utf8 and you're in trouble. Which means you have to fix this first.

What to check

You need to check in what encoding the data flow at each layer.

  • Check HTTP headers, headers.
  • Check what's really sent in body of the request.
  • Don't forget that MySQL has encoding almost everywhere:
    • Database
    • Tables
    • Columns
    • Server as a whole
    • Client
      Make sure that there's the right one everywhere.


If you receive data in e.g. windows-1250, and want to store in utf-8, then use this SQL before storing:

SET NAMES 'cp1250';

If you have data in DB as windows-1250 and want to retreive utf8, use:


Few more notes:

  • Don't rely on too "smart" tools to show the data. E.g. phpMyAdmin does (was doing when I was using it) encoding really bad. And it goes through all the layers so it's hard to find out.
  • Also, Internet Explorer had really stupid behavior of "guessing" the encoding based on weird rules.
  • Use simple editors where you can switch encoding. I recommend MySQL Workbench.

Apache is downloading php files instead of displaying them

For people who have found this post from Google almost 6 years in the future (and beyond!), you may run into this problem with Apache 2 and PHP 7 while also using the UserDir module.

Another possible cause of this problem could be that you are trying to run the script in a "user directory" from the the UserDir module. Running PHP scripts in user directories is disabled by default. You will run into this problem if the script is in the public_html directory in your home folder and you are trying to access it from http://localhost/~your_username.

To fix this, open up /etc/apache2/mods-enabled/php7.2.conf. You must comment or delete the tag block at the bottom that reads

<IfModule mod_userdir.c>
    <Directory /home/*/public_html>
        php_admin_flag engine Off

How to start MySQL server on windows xp


E:\mysql-5.1.39-win32\bin>mysql -u root -p

Python NLTK: SyntaxError: Non-ASCII character '\xc3' in file (Sentiment Analysis -NLP)

Add the following to the top of your file # coding=utf-8

If you go to the link in the error you can seen the reason why:

Defining the Encoding

Python will default to ASCII as standard encoding if no other encoding hints are given. To define a source code encoding, a magic comment must be placed into the source files either as first or second line in the file, such as: # coding=

Single quotes vs. double quotes in Python

I use double quotes in general, but not for any specific reason - Probably just out of habit from Java.

I guess you're also more likely to want apostrophes in an inline literal string than you are to want double quotes.

Detach (move) subdirectory into separate Git repository

The original question wants XYZ/ABC/(*files) to become ABC/ABC/(*files). After implementing the accepted answer for my own code, I noticed that it actually changes XYZ/ABC/(*files) into ABC/(*files). The filter-branch man page even says,

The result will contain that directory (and only that) as its project root."

In other words, it promotes the top-level folder "up" one level. That's an important distinction because, for example, in my history I had renamed a top-level folder. By promoting folders "up" one level, git loses continuity at the commit where I did the rename.

I lost contiuity after filter-branch

My answer to the question then is to make 2 copies of the repository and manually delete the folder(s) you want to keep in each. The man page backs me up with this:

[...] avoid using [this command] if a simple single commit would suffice to fix your problem

Styling HTML email for Gmail

Gmail started basic support for style tags in the head area. Found nothing official yet but you can easily try it yourself.
It seems to ignore class and id selectors but basic element selectors work.

<!doctype html>
    <style type="text/css">
    <p>Email content here</p>

it will create a style tag in its own head area limited to the div containing the mail body

<style>div.m14623dcb877eef15 p{font-family:Tahoma,sans-serif;font-size:12px;margin:0}</style>

Cannot find the declaration of element 'beans'

Found it on another thread that solved my problem... was using an internet connection less network.

In that case copy the xsd files from the url and place it next to the beans.xml file and change the xsi:schemaLocation as under:

 <beans xmlns="" 

What is boilerplate code?

"boilerplate code" is any seemingly repetitive code that shows up again and again in order to get some result that seems like it ought to be much simpler.

It's a subjective definition.

The term comes from "boilerplate" in the newspaper industry: wiki

Adding double quote delimiters into csv file

Double quotes can be achieved using VBA in one of two ways

First one is often the best

"...text..." & Chr(34) & "...text..."

Or the second one, which is more literal

"...text..." & """" & "...text..."

How to use LogonUser properly to impersonate domain user from workgroup client

Invalid login/password could be also related to issues in your DNS server - that's what happened to me and cost me good 5 hours of my life. See if you can specify ip address instead on domain name.

CSS3 transform: rotate; in IE9

Standard CSS3 rotate should work in IE9, but I believe you need to give it a vendor prefix, like so:

  -ms-transform: rotate(10deg);

It is possible that it may not work in the beta version; if not, try downloading the current preview version (preview 7), which is a later revision that the beta. I don't have the beta version to test against, so I can't confirm whether it was in that version or not. The final release version is definitely slated to support it.

I can also confirm that the IE-specific filter property has been dropped in IE9.

People have asked for some further documentation. As they say, this is quite limited, but I did find this page: which is useful for testing various CSS3 features in all browsers.

But testing the rotate feature on this page in IE9 preview caused it to crash fairly spectacularly.

However I have done some independant tests using -ms-transform:rotate() in IE9 in my own test pages, and it is working fine. So my conclusion is that the feature is implemented, but has got some bugs, possibly related to setting it dynamically.

Another useful reference point for which features are implemented in which browsers is -- see

Reviving this old answer because I recently found out about a hack called CSS Sandpaper which is relevant to the question and may make things easier.

The hack implements support for the standard CSS transform for for old versions of IE. So now you can add the following to your CSS:

-sand-transform: rotate(10deg);

...and have it work in IE 6/7/8, without having to use the filter syntax. (of course it still uses the filter syntax behind the scenes, but this makes it a lot easier to manage because it's using similar syntax to other browsers)

Using $_POST to get select option value from HTML

Use this way:

$selectOption = $_POST['taskOption'];

But it is always better to give values to your <option> tags.

<select name="taskOption">
  <option value="1">First</option>
  <option value="2">Second</option>
  <option value="3">Third</option>

jQuery return ajax result into outside variable

I solved it by doing like that:

var return_first = (function () {
        var tmp = $.ajax({
            'type': "POST",
            'dataType': 'html',
            'url': "ajax.php?first",
            'data': { 'request': "", 'target': arrange_url, 'method': 
                    method_target },
            'success': function (data) {
                tmp = data;
                return data;
      return tmp;
  • Be careful 'async':fale javascript will be asynchronous.

Have border wrap around text

Not sure, if that's what you want, but you could make the inner div an inline-element. This way the border should be wrapped only around the text. Even better than that is to use an inline-element for your title.

Solution 1

<div id="page" style="width: 600px;">
    <div id="title" style="display: inline; border...">Title</div>

Solution 2

<div id="page" style="width: 600px;">
    <span id="title" style="border...">Title</span>

Edit: Strange, SO doesn't interpret my code-examples correctly as block, so I had to use inline-code-method.

How can I pad a value with leading zeros?

Just an another solution, but I think it's more legible.

function zeroFill(text, size)_x000D_
  while (text.length < size){_x000D_
   text = "0" + text;_x000D_
  return text;_x000D_

How to validate an Email in PHP?

See the notes at


As of PHP 5.3.0, the regex extension is deprecated in favor of the PCRE extension. Calling this function will issue an E_DEPRECATED notice. See the list of differences for help on converting to PCRE.


preg_match(), which uses a Perl-compatible regular expression syntax, is often a faster alternative to ereg().

Sum values from an array of key-value pairs in JavaScript

Try the following

var myData = [['2013-01-22', 0], ['2013-01-29', 1], ['2013-02-05', 21]];_x000D_
var myTotal = 0;  // Variable to hold your total_x000D_
for(var i = 0, len = myData.length; i < len; i++) {_x000D_
    myTotal += myData[i][1];  // Iterate over your first array and then grab the second element add the values up_x000D_
document.write(myTotal); // 22 in this instance

No Spring WebApplicationInitializer types detected on classpath

I spent hours on this, and the solution was:

  • Stop Tomcat
  • "Project" menu -> Clean -> Clean all projects
  • Servers tab -> Tomcat -> Right click -> Clean...
  • Right click on project -> Run as -> Run on server

How to recompile with -fPIC

I had this problem when building FFMPEG static libraries (e.g. libavcodec.a) for Android x86_64 target platform (using Android NDK clang). When statically linking with my library the problem occured although all FFMPEG C -> object files (*.o) were compiled with -fPIC compile option:

requires dynamic R_X86_64_PC32 reloc against 'ff_pw_1023' 
which may overflow at runtime; recompile with -fPIC

The problem occured only for libavcodec.a and libswscale.a.

Source of this problem is that FFMPEG has assembler optimizations for x86* platforms e.g. the reported problem cause is in libavcodec/h264_qpel_10bit.asm -> h264_qpel_10bit.o.

When producing X86-64 bit static library (e.g. libavcodec.a) it looks like assembler files (e.g. libavcodec/h264_qpel_10bit.asm) uses some x86 (32bit) assembler commands which are incompatible when statically linking with x86-64 bit target library since they don't support required relocation type.

Possible solutions:

  1. compile all ffmpeg files with no assembler optimizations (for ffmpeg this is configure option: --disable-asm)
  2. produce dynamic libraries (e.g. and link them in your final library dynamically

I chose 1) and it solved the problem.


How do I redirect a user when a button is clicked?

if using JQuery, you can do this :

<script type="text/javascript">
    $('#buttonid').click(function () {
        document.location = '@Url.Action("ActionName","ControllerName")';

CSS hide scroll bar, but have element scrollable

if you really want to get rid of the scrollbar, split the information up into two separate pages.

Usability guidelines on scrollbars by Jakob Nielsen:

There are five essential usability guidelines for scrolling and scrollbars:

  • Offer a scrollbar if an area has scrolling content. Don't rely on auto-scrolling or on dragging, which people might not notice.
  • Hide scrollbars if all content is visible. If people see a scrollbar, they assume there's additional content and will be frustrated if they can't scroll.
  • Comply with GUI standards and use scrollbars that look like scrollbars.
  • Avoid horizontal scrolling on Web pages and minimize it elsewhere.
  • Display all important information above the fold. Users often decide whether to stay or leave based on what they can see without scrolling. Plus they only allocate 20% of their attention below the fold.

To make your scrollbar only visible when it is needed (i.e. when there is content to scroll down to), use overflow: auto.

How do I find numeric columns in Pandas?

You could use select_dtypes method of DataFrame. It includes two parameters include and exclude. So isNumeric would look like:

numerics = ['int16', 'int32', 'int64', 'float16', 'float32', 'float64']

newdf = df.select_dtypes(include=numerics)

Fixing the order of facets in ggplot

There are a couple of good solutions here.

Similar to the answer from Harpal, but within the facet, so doesn't require any change to underlying data or pre-plotting manipulation:

# Change this code:
facet_grid(.~size) + 
# To this code:
facet_grid(~factor(size, levels=c('50%','100%','150%','200%')))

This is flexible, and can be implemented for any variable as you change what element is faceted, no underlying change in the data required.

Access multiple elements of list knowing their index

Static indexes and small list?

Don't forget that if the list is small and the indexes don't change, as in your example, sometimes the best thing is to use sequence unpacking:

_,a1,a2,_,_,a3,_ = a

The performance is much better and you can also save one line of code:

 %timeit _,a1,b1,_,_,c1,_ = a
10000000 loops, best of 3: 154 ns per loop 
%timeit itemgetter(*b)(a)
1000000 loops, best of 3: 753 ns per loop
 %timeit [ a[i] for i in b]
1000000 loops, best of 3: 777 ns per loop
 %timeit map(a.__getitem__, b)
1000000 loops, best of 3: 1.42 µs per loop

adding noise to a signal in python

You can generate a noise array, and add it to your signal

import numpy as np

noise = np.random.normal(0,1,100)

# 0 is the mean of the normal distribution you are choosing from
# 1 is the standard deviation of the normal distribution
# 100 is the number of elements you get in array noise

MYSQL into outfile "access denied" - but my user has "ALL" access.. and the folder is CHMOD 777

For future readers, one easy way is as follows if they wish to export in bulk using bash,

akshay@ideapad:/tmp$ mysql -u someuser -p test -e "select * from offices"
Enter password: 
| officeCode | city          | phone            | addressLine1             | addressLine2 | state      | country   | postalCode | territory |
| 1          | San Francisco | +1 650 219 4782  | 100 Market Street        | Suite 300    | CA         | USA       | 94080      | NA        |
| 2          | Boston        | +1 215 837 0825  | 1550 Court Place         | Suite 102    | MA         | USA       | 02107      | NA        |
| 3          | NYC           | +1 212 555 3000  | 523 East 53rd Street     | apt. 5A      | NY         | USA       | 10022      | NA        |
| 4          | Paris         | +33 14 723 4404  | 43 Rue Jouffroy D'abbans | NULL         | NULL       | France    | 75017      | EMEA      |
| 5          | Tokyo         | +81 33 224 5000  | 4-1 Kioicho              | NULL         | Chiyoda-Ku | Japan     | 102-8578   | Japan     |
| 6          | Sydney        | +61 2 9264 2451  | 5-11 Wentworth Avenue    | Floor #2     | NULL       | Australia | NSW 2010   | APAC      |
| 7          | London        | +44 20 7877 2041 | 25 Old Broad Street      | Level 7      | NULL       | UK        | EC2N 1HN   | EMEA      |

If you're exporting by non-root user then set permission like below

root@ideapad:/tmp# mysql -u root -p
MariaDB[(none)]> UPDATE mysql.user SET File_priv = 'Y' WHERE user='someuser' AND host='localhost';

Restart or Reload mysqld

akshay@ideapad:/tmp$ sudo su
root@ideapad:/tmp#  systemctl restart mariadb

Sample code snippet

akshay@ideapad:/tmp$ cat 
#!/usr/bin/env bash


mysql -u"$user" -p"$password" "$database" <<EOF
INTO OUTFILE '/tmp/csvs/offices.csv' 
FROM offices;


akshay@ideapad:/tmp$ mkdir -p /tmp/csvs
akshay@ideapad:/tmp$ chmod +x
akshay@ideapad:/tmp$ ./ 
akshay@ideapad:/tmp$ cat /tmp/csvs/offices.csv 
"1"|"San Francisco"|"+1 650 219 4782"|"100 Market Street"|"Suite 300"|"CA"|"USA"|"94080"|"NA"
"2"|"Boston"|"+1 215 837 0825"|"1550 Court Place"|"Suite 102"|"MA"|"USA"|"02107"|"NA"
"3"|"NYC"|"+1 212 555 3000"|"523 East 53rd Street"|"apt. 5A"|"NY"|"USA"|"10022"|"NA"
"4"|"Paris"|"+33 14 723 4404"|"43 Rue Jouffroy D'abbans"|\N|\N|"France"|"75017"|"EMEA"
"5"|"Tokyo"|"+81 33 224 5000"|"4-1 Kioicho"|\N|"Chiyoda-Ku"|"Japan"|"102-8578"|"Japan"
"6"|"Sydney"|"+61 2 9264 2451"|"5-11 Wentworth Avenue"|"Floor #2"|\N|"Australia"|"NSW 2010"|"APAC"
"7"|"London"|"+44 20 7877 2041"|"25 Old Broad Street"|"Level 7"|\N|"UK"|"EC2N 1HN"|"EMEA"

Preferred way to create a Scala list

I always prefer List and I use "fold/reduce" before "for comprehension". However, "for comprehension" is preferred if nested "folds" are required. Recursion is the last resort if I can not accomplish the task using "fold/reduce/for".

so for your example, I will do:

((0 to 3) :\ List[Int]())(_ :: _)

before I do:

(for (x <- 0 to 3) yield x).toList

Note: I use "foldRight(:\)" instead of "foldLeft(/:)" here because of the order of "_"s. For a version that does not throw StackOverflowException, use "foldLeft" instead.

Kill detached screen session

Alternatively, while in your screen session all you have to do is type exit

This will kill the shell session initiated by the screen, which effectively terminates the screen session you are on.

No need to bother with screen session id, etc.

How to force DNS refresh for a website?

It might be possible to delete the Zone Record entirely, then recreate it exactly as you want it. Perhaps this will force a full propagation. If I'm wrong, somebody tell me and I'll delete this suggestion. Also, I don't know how to save a Zone Record and recreate it using WHM or any other tool.

I do know that when I deleted a hosting account today and recreated it, the original Zone Record seemed to be propagated instantly to a DNS resolver up the line from my computer. That is good evidence it works.

How to get the title of HTML page with JavaScript?

Use document.title:

<title>Title test</title>

MDN Web Docs

Java replace issues with ' (apostrophe/single quote) and \ (backslash) together

If you want to use it in JavaScript then you can use


But in Java


will work perfectly.

SP: special character

Otherwise you can use Apache's EscapeUtil. It will solve your problem.

How to use Google fonts in React.js?

Had the same issue. Turns out I was using " instead of '.

use @import url('within single quotes'); like this

not @import url("within double quotes"); like this

Is there a cross-domain iframe height auto-resizer that works?

I got the solution for setting the height of the iframe dynamically based on it's content. This works for the cross domain content. There are some steps to follow to achieve this.

  1. Suppose you have added iframe in "" web page

    <div> <iframe id="IframeId" src="http://xyz.pqr/contactpage" style="width:100%;" onload="setIframeHeight(this)"></iframe> </div>

  2. Next you have to bind windows "message" event under web page ""

window.addEventListener('message', function (event) {
//Here We have to check content of the message event  for safety purpose
//event data contains message sent from page added in iframe as shown in step 3
if ("FrameHeight")) {
        //Set height of the Iframe

On iframe load you have to send message to iframe window content with "FrameHeight" message:

function setIframeHeight(ifrm) {
   var height = ifrm.contentWindow.postMessage("FrameHeight", "*");   
  1. On main page that added under iframe here "xyz.pqr/contactpage" you have to bind windows "message" event where all messages are going to receive from parent window of ""
window.addEventListener('message', function (event) {

    // Need to check for safety as we are going to process only our messages
    // So Check whether event with data(which contains any object) contains our message here its "FrameHeight"
   if ( == "FrameHeight") {

        //event.source contains parent page window object 
        //which we are going to use to send message back to main page here ""

        //parentSourceWindow = event.source;

        //Calculate the maximum height of the page
        var body = document.body, html = document.documentElement;
        var height = Math.max(body.scrollHeight, body.offsetHeight,
            html.clientHeight, html.scrollHeight, html.offsetHeight);

       // Send height back to parent page ""
        event.source.postMessage({ "FrameHeight": height }, "*");       

How to drop all tables from the database with CLI in Django?

The command ./ sqlclear or ./ sqlflush seems to clear the table and not delete them, however if you want to delete the complete database try this : flush.

Warning: this will delete your database completely and you will lose all your data, so if that not important go ahead and try it.

How do I use Spring Boot to serve static content located in Dropbox folder?

FWIW, I didn't have any success with the spring.resources.static-locations recommended above; what worked for me was setting spring.thymeleaf.prefix:


AttributeError: 'dict' object has no attribute 'predictors'

The dict.items iterates over the key-value pairs of a dictionary. Therefore for key, value in dictionary.items() will loop over each pair. This is documented information and you can check it out in the official web page, or even easier, open a python console and type help(dict.items). And now, just as an example:

>>> d = {'hello': 34, 'world': 2999}
>>> for key, value in d.items():
...   print key, value
world 2999
hello 34

The AttributeError is an exception thrown when an object does not have the attribute you tried to access. The class dict does not have any predictors attribute (now you know where to check it :) ), and therefore it complains when you try to access it. As easy as that.

C# LINQ select from list

In likeness of how I found this question using Google, I wanted to take it one step further. Lets say I have a string[] states and a db Entity of StateCounties and I just want the states from the list returned and not all of the StateCounties.

I would write:

db.StateCounties.Where(x => states.Any(s => x.State.Equals(s))).ToList();

I found this within the sample of CheckBoxList for nu-get.

Converting Integer to String with comma for thousands

You ask for quickest, but perhaps you mean "best" or "correct" or "typical"?

You also ask for commas to indicate thousands, but perhaps you mean "in normal human readable form according to the local custom of your user"?

You do it as so:

    int i = 35634646;
    String s = NumberFormat.getIntegerInstance().format(i);

Americans will get "35,634,646"

Germans will get "35.634.646"

Swiss Germans will get "35'634'646"

SQLite - getting number of rows in a database

Not sure if I understand your question, but max(id) won't give you the number of lines at all. For example if you have only one line with id = 13 (let's say you deleted the previous lines), you'll have max(id) = 13 but the number of rows is 1. The correct (and fastest) solution is to use count(). BTW if you wonder why there's a star, it's because you can count lines based on a criteria.

Automatically start forever (node) on system restart

I tried lots of the above answers. None of them worked for me. My app is installed in /home and as user, not as root. This probably means that when the above mentioned start scripts run, /home is not mounted yet, so the app is not started.

Then I found these instructions by Digital Ocean:

Using PM2 as explained was very simple and works perfectly: My virtual servers had two physical crashes since - downtime was only about a minute.

Fetch: POST json data

With ES2017 async/await support, this is how to POST a JSON payload:

(async () => {_x000D_
  const rawResponse = await fetch('', {_x000D_
    method: 'POST',_x000D_
    headers: {_x000D_
      'Accept': 'application/json',_x000D_
      'Content-Type': 'application/json'_x000D_
    body: JSON.stringify({a: 1, b: 'Textual content'})_x000D_
  const content = await rawResponse.json();_x000D_

Can't use ES2017? See @vp_art's answer using promises

The question however is asking for an issue caused by a long since fixed chrome bug.
Original answer follows.

chrome devtools doesn't even show the JSON as part of the request

This is the real issue here, and it's a bug with chrome devtools, fixed in Chrome 46.

That code works fine - it is POSTing the JSON correctly, it just cannot be seen.

I'd expect to see the object I've sent back

that's not working because that is not the correct format for JSfiddle's echo.

The correct code is:

var payload = {
    a: 1,
    b: 2

var data = new FormData();
data.append( "json", JSON.stringify( payload ) );

    method: "POST",
    body: data
.then(function(res){ return res.json(); })
.then(function(data){ alert( JSON.stringify( data ) ) })

For endpoints accepting JSON payloads, the original code is correct

Call a function with argument list in python

A small addition to previous answers, since I couldn't find a solution for a problem, which is not worth opening a new question, but led me here.

Here is a small code snippet, which combines lists, zip() and *args, to provide a wrapper that can deal with an unknown amount of functions with an unknown amount of arguments.

def f1(var1, var2, var3):

def f2(var1, var2):

def f3():
    print('f3, empty')

def wrapper(a,b, func_list, arg_list):
    for f,var in zip(func_list,arg_list):

f_list = [f1, f2, f3]
a_list = [[1,2,3], [4,5], []]

wrapper('begin', 'end', f_list, a_list)

Keep in mind, that zip() does not provide a safety check for lists of unequal length, see zip iterators asserting for equal length in python.

Set folder for classpath

Use the command as

java -classpath ".;C:\MyLibs\a\*;D:\MyLibs\b\*" <your-class-name>

The above command will set the mentioned paths to classpath only once for executing the class named TestClass.

If you want to execute more then one classes, then you can follow this

set classpath=".;C:\MyLibs\a\*;D:\MyLibs\b\*"

After this you can execute as many classes as you want just by simply typing

java <your-class-name>

The above command will work till you close the command prompt. But after closing the command prompt, if you will reopen the command prompt and try to execute some classes, then you have to again set the classpath with the help of any of the above two mentioned methods.(First method for executing one class and second one for executing more classes)

If you want to set the classpth only once so that it could work for everytime, then do as follows

1. Right click on "My Computer" icon
2. Go to the "properties"
3. Go to the "Advanced System Settings" or "Advance Settings"
4. Go to the "Environment Variable"
5. Create a new variable at the user variable by giving the information as below
    a.  Variable Name-     classpath
    b.  Variable Value-    .;C:\program files\jdk 1.6.0\bin;C:\MyLibs\a\';C:\MyLibs\b\*
6.Apply this and you are done.

Remember this will work every time. You don't need to explicitly set the classpath again and again.

NOTE: If you want to add some other libs after some day, then don't forget to add a semi-colon at the end of the "variable-value" of the "Environment Variable" and then type the path of your new libs after the semi-colon. Because semi-colon separates the paths of different directories.

Hope this will help you.

jQuery ajax success callback function definition

I would write :

var handleData = function (data) {
    //do some stuff

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

Does static constexpr variable inside a function make sense?

In addition to given answer, it's worth noting that compiler is not required to initialize constexpr variable at compile time, knowing that the difference between constexpr and static constexpr is that to use static constexpr you ensure the variable is initialized only once.

Following code demonstrates how constexpr variable is initialized multiple times (with same value though), while static constexpr is surely initialized only once.

In addition the code compares the advantage of constexpr against const in combination with static.

#include <iostream>
#include <string>
#include <cassert>
#include <sstream>

const short const_short = 0;
constexpr short constexpr_short = 0;

// print only last 3 address value numbers
const short addr_offset = 3;

// This function will print name, value and address for given parameter
void print_properties(std::string ref_name, const short* param, short offset)
    // determine initial size of strings
    std::string title = "value \\ address of ";
    const size_t ref_size = ref_name.size();
    const size_t title_size = title.size();
    assert(title_size > ref_size);

    // create title (resize)
    title.append(" is ");
    title.append(title_size - ref_size, ' ');

    // extract last 'offset' values from address
    std::stringstream addr;
    addr << param;
    const std::string addr_str = addr.str();
    const size_t addr_size = addr_str.size();
    assert(addr_size - offset > 0);

    // print title / ref value / address at offset
    std::cout << title << *param << " " << addr_str.substr(addr_size - offset) << std::endl;

// here we test initialization of const variable (runtime)
void const_value(const short counter)
    static short temp = const_short;
    const short const_var = ++temp;
    print_properties("const", &const_var, addr_offset);

    if (counter)
        const_value(counter - 1);

// here we test initialization of static variable (runtime)
void static_value(const short counter)
    static short temp = const_short;
    static short static_var = ++temp;
    print_properties("static", &static_var, addr_offset);

    if (counter)
        static_value(counter - 1);

// here we test initialization of static const variable (runtime)
void static_const_value(const short counter)
    static short temp = const_short;
    static const short static_var = ++temp;
    print_properties("static const", &static_var, addr_offset);

    if (counter)
        static_const_value(counter - 1);

// here we test initialization of constexpr variable (compile time)
void constexpr_value(const short counter)
    constexpr short constexpr_var = constexpr_short;
    print_properties("constexpr", &constexpr_var, addr_offset);

    if (counter)
        constexpr_value(counter - 1);

// here we test initialization of static constexpr variable (compile time)
void static_constexpr_value(const short counter)
    static constexpr short static_constexpr_var = constexpr_short;
    print_properties("static constexpr", &static_constexpr_var, addr_offset);

    if (counter)
        static_constexpr_value(counter - 1);

// final test call this method from main()
void test_static_const()
    constexpr short counter = 2;

    std::cout << std::endl;

    std::cout << std::endl;

    std::cout << std::endl;

    std::cout << std::endl;

    std::cout << std::endl;

Possible program output:

value \ address of const is               1 564
value \ address of const is               2 3D4
value \ address of const is               3 244

value \ address of static is              1 C58
value \ address of static is              1 C58
value \ address of static is              1 C58

value \ address of static const is        1 C64
value \ address of static const is        1 C64
value \ address of static const is        1 C64

value \ address of constexpr is           0 564
value \ address of constexpr is           0 3D4
value \ address of constexpr is           0 244

value \ address of static constexpr is    0 EA0
value \ address of static constexpr is    0 EA0
value \ address of static constexpr is    0 EA0

As you can see yourself constexpr is initilized multiple times (address is not the same) while static keyword ensures that initialization is performed only once.

Row Offset in SQL Server

You can use ROW_NUMBER() function to get what you want:


What is the difference between <%, <%=, <%# and -%> in ERB in Rails?

I've added the <%% literal tag delimiter as an answer to this because of its obscurity. This will tell erb not to interpret the <% part of the tag which is necessary for js apps like displaying chart.js tooltips etc.

Update (Fixed broken link)

Everything about ERB can now be found here:

Disable submit button when form invalid with AngularJS

To add to this answer. I just found out that it will also break down if you use a hyphen in your form name (Angular 1.3):

So this will not work:

<form name="my-form">
    <input name="myText" type="text" ng-model="mytext" required />
    <button ng-disabled="my-form.$invalid">Save</button>

Input button target="_blank" isn't causing the link to load in a new window/tab

In a similar use case, this worked for me...

<button onclick="'', '_blank');">  My Button </button>

How do I return JSON without using a template in Django?

You could also check the request accept content type as specified in the rfc. That way you can render by default HTML and where your client accept application/jason you can return json in your response without a template being required

Making button go full-width?

Why not use the Bootstrap predefined class input-block-level that does the job?

<a href="#" class="btn input-block-level">Full-Width Button</a> <!-- BS2 -->
<a href="#" class="btn form-control">Full-Width Button</a> <!-- BS3 -->

<!-- And let's join both for BS# :) -->
<a href="#" class="btn input-block-level form-control">Full-Width Button</a>

Learn more here in the Control Sizing^ section.

Get second child using jQuery

In addition to using jQuery methods, you can use the native cells collection that the <tr> gives you.


Assuming t is a DOM element, you could bypass the jQuery object creation.


How to add a list item to an existing unordered list?

You can do it also in more 'object way' and still easy-to-read:

$('#content ul').append(
            $('<span>').attr('class', 'tab').append("Message center")

You don't have to fight with quotes then, but must keep trace of braces :)

pandas get column average/mean

You can easily follow the following code

import pandas as pd 
import numpy as np 
classxii = {'Name':['Karan','Ishan','Aditya','Anant','Ronit'],

df = pd.DataFrame(classxii,index = ['a','b','c','d','e'],columns=['Name','Subject','Score','Grade'])

#use the below for mean if you already have a dataframe
print('mean of score is:')

How to avoid the "Circular view path" exception with Spring MVC test

Add the annotation @ResponseBody to your method return.

Oracle - Best SELECT statement for getting the difference in minutes between two DateTime columns?

By default, oracle date subtraction returns a result in # of days.

So just multiply by 24 to get # of hours, and again by 60 for # of minutes.


  round((second_date - first_date) * (60 * 24),2) as time_in_minutes
    to_date('01/01/2008 01:30:00 PM','mm/dd/yyyy hh:mi:ss am') as first_date
   ,to_date('01/06/2008 01:35:00 PM','mm/dd/yyyy HH:MI:SS AM') as second_date
  ) test_data

(SC) DeleteService FAILED 1072

I had this error also, make sure the exe the service is pointing to is stopped. Also make sure you don't have any Windows dialog boxes behind your other windows. That is why mine wasn't deleting. There was a windows message behind it saying this service has been deleted or something similar.. just had to click ok, there it went.

Updating and committing only a file's permissions using git version control

By default, git will update execute file permissions if you change them. It will not change or track any other permissions.

If you don't see any changes when modifying execute permission, you probably have a configuration in git which ignore file mode.

Look into your project, in the .git folder for the config file and you should see something like this:

    filemode = false

You can either change it to true in your favorite text editor, or run:

git config core.filemode true

Then, you should be able to commit normally your files. It will only commit the permission changes.

Archive the artifacts in Jenkins

An artifact can be any result of your build process. The important thing is that it doesn't matter on which client it was built it will be tranfered from the workspace back to the master (server) and stored there with a link to the build. The advantage is that it is versionized this way, you only have to setup backup on your master and that all artifacts are accesible via the web interface even if all build clients are offline.

It is possible to define a regular expression as the artifact name. In my case I zipped all the files I wanted to store in one file with a constant name during the build.

Fatal error: Class 'SoapClient' not found

For PHP 8:

sudo apt update
sudo apt-get install php8.0-soap

php resize image on upload

<form action="<?php echo $_SERVER["PHP_SELF"];  ?>" method="post" enctype="multipart/form-data" id="something" class="uniForm">
    <input name="new_image" id="new_image" size="30" type="file" class="fileUpload" />
    <button name="submit" type="submit" class="submitButton">Upload Image</button>

      if (isset ($_FILES['new_image'])){              
          $imagename = $_FILES['new_image']['name'];
          $source = $_FILES['new_image']['tmp_name'];
          $target = "images/".$imagename;

          if($type=="image/jpeg" || $type=="image/jpg"){
          move_uploaded_file($source, $target);
          //orginal image making part

          $imagepath = $imagename;
          $save = "images/" . $imagepath; //This is the new file you saving
          $file = "images/" . $imagepath; //This is the original file
          list($width, $height) = getimagesize($file) ;
          $modwidth = 1000;
          $diff = $width / $modwidth;
          $modheight = $height / $diff;   
          $tn = imagecreatetruecolor($modwidth, $modheight) ;
          $image = imagecreatefromjpeg($file) ;
          imagecopyresampled($tn, $image, 0, 0, 0, 0, $modwidth, $modheight, $width, $height) ;
          echo "Large image: <img src='images/".$imagepath."'><br>";                     
          imagejpeg($tn, $save, 100) ;

          //thumbnail image making part
          $save = "images/thumb/" . $imagepath; //This is the new file you saving
          $file = "images/" . $imagepath; //This is the original file   
          list($width, $height) = getimagesize($file) ;
          $modwidth = 150;
          $diff = $width / $modwidth;
          $modheight = $height / $diff;
          $tn = imagecreatetruecolor($modwidth, $modheight) ;
          $image = imagecreatefromjpeg($file) ;
          imagecopyresampled($tn, $image, 0, 0, 0, 0, $modwidth, $modheight, $width, $height) ;
        //echo "Thumbnail: <img src='images/sml_".$imagepath."'>";
          imagejpeg($tn, $save, 100) ;
            echo "File is not image";

How to make a floated div 100% height of its parent?

Actually, as long as the parent element is positioned, you can set the child's height to 100%. Namely, in case you don't want the parent to be absolutely positioned. Let me explain further:

    #outer2 {
        padding-left: 23px;
        position: relative; 
        border: 1px solid red; 
    #inner2 {
        border: 1px solid black; 

<div id='outer2'>
    <div id='inner2'>

Regex to check with starts with http://, https:// or ftp://

test.matches() method checks all text.use test.find()

Get value from hidden field using jQuery

This should work:

var hv = $('#h_v').val();

Retrieve the maximum length of a VARCHAR column in SQL Server

Watch out!! If there's spaces they will not be considered by the LEN method in T-SQL. Don't let this trick you and use

select max(datalength(Desc)) from table_name

git clone through ssh

Easy way to do this issue
try this.

Step 1:

ls -al ~/.ssh

enter image description here

Step 2:


(using enter key for default value) enter image description here Step 3: To setup config file

vim /c/Users/Willie/.ssh/config

User git
IdentityFile ~/.ssh/id_rsa

Step 4:

git clone [email protected]:<username>/test2.git

enter image description here

Step 5:
When you finished Step 4
1.the test2.git file will be download done will get the new file(known_hosts) in the ~/.ssh
enter image description here

PS: I create the id_rsa and id_rsa.ub by meself and I deliver it to the Gitlab server. using both keys to any client-sides(windows and Linux).

Illegal mix of collations error in MySql

Check the collation type of each table, and make sure that they have the same collation.

After that check also the collation type of each table field that you have use in operation.

I had encountered the same error, and that tricks works on me.

Scroll RecyclerView to show selected item on top

I don't know why I didn't find the best answer but its really simple.


No errors

Creates Animations

maven compilation failure

Add <sourceDirectory>src</sourceDirectory> in your pom.xml with proper reference. Adding this solved my problem

Create a global variable in TypeScript

I found a way that works if I use JavaScript combined with TypeScript.


declare var log: log4javascript.Logger;


log = null;


import './log-declaration.js';

// Call stuff to actually setup log.  
// Similar to this:
log = functionToSetupLog();

This puts it in the global scope and TypeScript knows about it. So I can use it in all my files.

NOTE: I think this only works because I have the allowJs TypeScript option set to true.

If someone posts an pure TypeScript solution, I will accept that.

Regular expression for matching latitude/longitude coordinates?

Try this:


What's the difference between setWebViewClient vs. setWebChromeClient?

WebViewClient provides the following callback methods, with which you can interfere in how WebView makes a transition to the next content.

void doUpdateVisitedHistory (WebView view, String url, boolean isReload)
void onFormResubmission (WebView view, Message dontResend, Message resend)
void onLoadResource (WebView view, String url)
void onPageCommitVisible (WebView view, String url)
void onPageFinished (WebView view, String url)
void onPageStarted (WebView view, String url, Bitmap favicon)
void onReceivedClientCertRequest (WebView view, ClientCertRequest request)
void onReceivedError (WebView view, int errorCode, String description, String failingUrl)
void onReceivedError (WebView view, WebResourceRequest request, WebResourceError error)
void onReceivedHttpAuthRequest (WebView view, HttpAuthHandler handler, String host, String realm)
void onReceivedHttpError (WebView view, WebResourceRequest request, WebResourceResponse errorResponse)
void onReceivedLoginRequest (WebView view, String realm, String account, String args)
void onReceivedSslError (WebView view, SslErrorHandler handler, SslError error)
boolean onRenderProcessGone (WebView view, RenderProcessGoneDetail detail)
void onSafeBrowsingHit (WebView view, WebResourceRequest request, int threatType, SafeBrowsingResponse callback)
void onScaleChanged (WebView view, float oldScale, float newScale)
void onTooManyRedirects (WebView view, Message cancelMsg, Message continueMsg)
void onUnhandledKeyEvent (WebView view, KeyEvent event)
WebResourceResponse shouldInterceptRequest (WebView view, WebResourceRequest request)
WebResourceResponse shouldInterceptRequest (WebView view, String url)
boolean shouldOverrideKeyEvent (WebView view, KeyEvent event)
boolean shouldOverrideUrlLoading (WebView view, WebResourceRequest request)
boolean shouldOverrideUrlLoading (WebView view, String url)

WebChromeClient provides the following callback methods, with which your Activity or Fragment can update the surroundings of WebView.

Bitmap getDefaultVideoPoster ()
View getVideoLoadingProgressView ()
void getVisitedHistory (ValueCallback<String[]> callback)
void onCloseWindow (WebView window)
boolean onConsoleMessage (ConsoleMessage consoleMessage)
void onConsoleMessage (String message, int lineNumber, String sourceID)
boolean onCreateWindow (WebView view, boolean isDialog, boolean isUserGesture, Message resultMsg)
void onExceededDatabaseQuota (String url, String databaseIdentifier, long quota, long estimatedDatabaseSize, long totalQuota, WebStorage.QuotaUpdater quotaUpdater)
void onGeolocationPermissionsHidePrompt ()
void onGeolocationPermissionsShowPrompt (String origin, GeolocationPermissions.Callback callback)
void onHideCustomView ()
boolean onJsAlert (WebView view, String url, String message, JsResult result)
boolean onJsBeforeUnload (WebView view, String url, String message, JsResult result)
boolean onJsConfirm (WebView view, String url, String message, JsResult result)
boolean onJsPrompt (WebView view, String url, String message, String defaultValue, JsPromptResult result)
boolean onJsTimeout ()
void onPermissionRequest (PermissionRequest request)
void onPermissionRequestCanceled (PermissionRequest request)
void onProgressChanged (WebView view, int newProgress)
void onReachedMaxAppCacheSize (long requiredStorage, long quota, WebStorage.QuotaUpdater quotaUpdater)
void onReceivedIcon (WebView view, Bitmap icon)
void onReceivedTitle (WebView view, String title)
void onReceivedTouchIconUrl (WebView view, String url, boolean precomposed)
void onRequestFocus (WebView view)
void onShowCustomView (View view, int requestedOrientation, WebChromeClient.CustomViewCallback callback)
void onShowCustomView (View view, WebChromeClient.CustomViewCallback callback)
boolean onShowFileChooser (WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams)

Why are elementwise additions much faster in separate loops than in a combined loop?

It's because the CPU doesn't have so many cache misses (where it has to wait for the array data to come from the RAM chips). It would be interesting for you to adjust the size of the arrays continually so that you exceed the sizes of the level 1 cache (L1), and then the level 2 cache (L2), of your CPU and plot the time taken for your code to execute against the sizes of the arrays. The graph shouldn't be a straight line like you'd expect.

Get the current language in device

This solution worked for me. This will return you the android device's language (not the app's local language)

String locale = getApplicationContext().getResources().getConfiguration().locale.getLanguage();

This will return "en" or "de" or "fr" or whatever your device language is set to.

SQL Server convert string to datetime

For instance you can use

update tablename set datetimefield='19980223 14:23:05'
update tablename set datetimefield='02/23/1998 14:23:05'
update tablename set datetimefield='1998-12-23 14:23:05'
update tablename set datetimefield='23 February 1998 14:23:05'
update tablename set datetimefield='1998-02-23T14:23:05'

You need to be careful of day/month order since this will be language dependent when the year is not specified first. If you specify the year first then there is no problem; date order will always be year-month-day.

Formatting "yesterday's" date in python

Could I just make this somewhat more international and format the date according to the international standard and not in the weird month-day-year, that is common in the US?

from datetime import datetime, timedelta

yesterday = - timedelta(days=1)

Ruby send JSON request

A simple json POST request example for those that need it even simpler than what Tom is linking to:

require 'net/http'

uri = URI.parse("")
response = Net::HTTP.post_form(uri, {"search" => "Berlin"})

Find largest and smallest number in an array

You can initialize after filling the array or you can write:

 small =~ unsigned(0)/2; // Using the bit-wise complement to flip 0's bits and dividing by 2 because unsigned can hold twice the +ve value an

integer can hold.

 big =- 1*(small) - 1;

instead of:

big = small = values[0]

because when you write this line before filling the array, big and small values will equal to a random leftover value (as integer is a POD) from the memory and if those numbers are either bigger or smaller than any other value in you array, you will get them as an output.

How do I properly set the Datetimeindex for a Pandas datetime object in a dataframe?

To simplify Kirubaharan's answer a bit:

df['Datetime'] = pd.to_datetime(df['date'] + ' ' + df['time'])
df = df.set_index('Datetime')

And to get rid of unwanted columns (as OP did but did not specify per se in the question):

df = df.drop(['date','time'], axis=1)

python pandas: Remove duplicates by columns A, keeping the row with the highest value in column B

I would sort the dataframe first with Column B descending, then drop duplicates for Column A and keep first

df = df.sort_values(by='B', ascending=False)
df = df.drop_duplicates(subset='A', keep="first")

without any groupby

PHP CSV string to array

I have used following function to parse csv string to associative array

public function csvToArray($file) {
    $rows = array();
    $headers = array();
    if (file_exists($file) && is_readable($file)) {
        $handle = fopen($file, 'r');
        while (!feof($handle)) {
            $row = fgetcsv($handle, 10240, ',', '"');
            if (empty($headers))
                $headers = $row;
            else if (is_array($row)) {
                array_splice($row, count($headers));
                $rows[] = array_combine($headers, $row);
    } else {
        throw new Exception($file . ' doesn`t exist or is not readable.');
    return $rows;

if your csv file name is mycsv.csv then you call this function as:

$dataArray = csvToArray(mycsv.csv);

you can get this script also in

Javascript Equivalent to C# LINQ Select

I am answering the title of the question rather than the original question which was more specific.

With the new features of Javascript like iterators and generator functions and objects, something like LINQ for Javascript becomes possible. Note that linq.js, for example, uses a completely different approach, using regular expressions, probably to overcome the lack of support in the language at the time.

With that being said, I've written a LINQ library for Javascript and you can find it at Comments and discussion at

From previous answers, only Manipula seems to be what one would expect from a LINQ port in Javascript.

Android - shadow on text?

 <style name="WhiteTextWithShadow" parent="@android:style/TextAppearance">
    <item name="android:shadowDx">1</item>
    <item name="android:shadowDy">1</item>
    <item name="android:shadowRadius">1</item>
    <item name="android:shadowColor">@android:color/black</item>
    <item name="android:textColor">@android:color/white</item>

then use as

            tools:text="Today, May 21"

With block equivalent in C#?

About 3/4 down the page in the "Using Objects" section:


With hero 
  .Name = "SpamMan" 
  .PowerLevel = 3 
End With 


//No "With" construct
hero.Name = "SpamMan"; 
hero.PowerLevel = 3; 

JIRA JQL searching by date - is there a way of getting Today() (Date) instead of Now() (DateTime)

I run it like this -

created > startOfDay(-0d)

It gives me all issues created today. When you change -0d to -1d, it will give you all issues created yesterday and today.

How to add line break for UILabel?

Just do it like this

NSString * strCheck = @"A\nB";

strCheck = [strCheck stringByReplacingOccurrencesOfString:@"\\n" withString:@"\n"];  //This is to prevent for fetching string from plist or data structure

label.numberOfLines = 0;

label.lineBreakMode = NSLineBreakByWordWrapping;

label.text = strCheck;

Alter table add multiple columns ms sql

Can with defaulth value (T-SQL)

    HasPhotoInReadyStorage BIT NULL, --this column is nullable
    HasPhotoInWorkStorage BIT NOT NULL, --this column is not nullable
    HasPhotoInMaterialStorage BIT NOT NULL DEFAULT(0) --this column default value is false

Creating a triangle with for loops

This lets you have a little more control and an easier time making it:

public static int biggestoddnum = 31;

public static void main(String[] args) {
    for (int i=1; i<biggestoddnum; i += 2)
        for (int k=0; k < ((biggestoddnum / 2) - i / 2); k++)
            System.out.print(" ");
        for (int j=0; j<i; j++)

Just change public static int biggestoddnum's value to whatever odd number you want it to be, and the for(int k...) has been tested to work.

Appending values to dictionary in Python

You should use append to add to the list. But also here are few code tips:

I would use dict.setdefault or defaultdict to avoid having to specify the empty list in the dictionary definition.

If you use prev to to filter out duplicated values you can simplfy the code using groupby from itertools Your code with the amendments looks as follows:

import itertools
def make_drug_dictionary(data):
    drug_dictionary = {}
    for key, row in itertools.groupby(data, lambda x: x[11]):
    return drug_dictionary

If you don't know how groupby works just check this example:

>>> list(key for key, val in itertools.groupby('aaabbccddeefaa'))
['a', 'b', 'c', 'd', 'e', 'f', 'a']


I have discovered that you cannot have conditionals outside of the stored procedure in mysql. This is why the syntax error. As soon as I put the code that I needed between

   SELECT FIRST_DAY(CURDATE()) INTO @checkweekday;
   SELECT DAY(@checkweekday) INTO @checkday;
   SET @daycount = 0;
   SET @workdays = 0;

     WHILE(@daycount < @totaldays) DO
       IF (WEEKDAY(@checkweekday) < 5) THEN
         SET @workdays = @workdays+1;
       END IF;
       SET @daycount = @daycount+1;
       SELECT ADDDATE(@checkweekday, INTERVAL 1 DAY) INTO @checkweekday;

Just for others:

If you are not sure how to create a routine in phpmyadmin you can put this in the SQL query

    delimiter ;;
    drop procedure if exists test2;;
    create procedure test2()
    select ‘Hello World’;

Run the query. This will create a stored procedure or stored routine named test2. Now go to the routines tab and edit the stored procedure to be what you want. I also suggest reading if you are beginning with stored procedures.

The first_day function you need is: How to get first day of every corresponding month in mysql?

Showing the Procedure is working Simply add the following line below END WHILE and above END

    SELECT @curmonth,@curmonthname,@totaldays,@daycount,@workdays,@checkweekday,@checkday;

Then use the following code in the SQL Query Window.

    call test2 /* or whatever you changed the name of the stored procedure to */

NOTE: If you use this please keep in mind that this code does not take in to account nationally observed holidays (or any holidays for that matter).

How can I make an entire HTML form "readonly"?

Another simple way that's supported by all browsers would be:


<form class="disabled">
  <input type="text" name="name" />
  <input type="radio" name="gender" value="male">
  <input type="radio" name="gender" value="female">
  <input type="checkbox" name="vegetarian">


.disabled {
  pointer-events: none;
  opacity: .4;

But be aware, that the tabbing still works with this approach and the elements with focus can still be manipulated by the user.

Display label text with line breaks in c#

Or simply add one line of:

Text='<%# Eval("Comments").ToString().Replace("\n","<br />") %>'

Have Excel formulas that return 0, make the result blank

The normal way would be the IF statement, though simpler than your example:


No need to do gyrations with the formula, since zero values trigger the false condition.

Microsoft.ACE.OLEDB.12.0 provider is not registered

See my post on a similar Stack Exchange thread

I had version 15, not 12 installed, which I found out by running this PowerShell code...


...which gave me this result (I've removed other data sources for brevity)...

SOURCES_NAME              SOURCES_DESCRIPTION                                                                       
------------              -------------------                                                                       
Microsoft.ACE.OLEDB.15.0  Microsoft Office 15.0 Access Database Engine OLE DB Provider

Getting reference to the top-most view/window in iOS application

Just use this code if you want to add a view above of everything in the screen.

[[UIApplication sharedApplication].keyWindow addSubView: yourView];

Replace tabs with spaces in vim

IIRC, something like:

set tabstop=2 shiftwidth=2 expandtab

should do the trick. If you already have tabs, then follow it up with a nice global RE to replace them with double spaces.

If you already have tabs you want to replace,


iFrame src change event detection?

Answer based on JQuery < 3

    alert('frame has (re)loaded');

As mentioned by subharb, as from JQuery 3.0 this needs to be changed to:

$('#iframe').on('load', function() {
    alert('frame has (re)loaded ');

The imported project "C:\Microsoft.CSharp.targets" was not found

ok so what if it say this: between the gt/lt signs

Import Project="$(MSBuildExtensionsPath)\Microsoft\Silverlight\v3.0\Microsoft.Silverlight.CSharp.targets" /

how do i fix the targets error?

I also found that import string in a demo project (specifically "Build your own MVVM Framework" by Rob Eisenburg).

If you replace that import with the one suggested by lomaxx VS2010 RTM reports that you need to install this.

Get MD5 hash of big files in Python

I don't like loops. Based on @Nathan Feger:

md5 = hashlib.md5()
with open(filename, 'rb') as f:
    functools.reduce(lambda _, c: md5.update(c), iter(lambda: * 128), b''), None)

PHP: cannot declare class because the name is already in use

I had this problem before and to fix this, Just make sure :

  1. You did not create an instance of this class before
  2. If you call this from a class method, make sure the __destruct is set on the class you called from.

My problem (before) :
I had class : Core, Router, Permissions and Render Core include's the Router class, Router then calls Permissions class, then Router __destruct calls the Render class and the error "Cannot declare class because the name is already in use" appeared.

Solution :
I added __destruct on Permission class and the __destruct was empty and it's fixed...

How can I show/hide a specific alert with twitter bootstrap?

On top of all the previous answers, dont forget to hide your alert before using it with a simple style="display:none;"

<div class="alert alert-success" id="passwordsNoMatchRegister" role="alert" style="display:none;" >Message of the Alert</div>

Then use either:




Git command to checkout any branch and overwrite local changes

The new git-switch command (starting in GIT 2.23) also has a flag --discard-changes which should help you. git pull might be necessary afterwards.

Warning: it's still considered to be experimental.

Count the Number of Tables in a SQL Server Database

You can use INFORMATION_SCHEMA.TABLES to retrieve information about your database tables.

As mentioned in the Microsoft Tables Documentation:

INFORMATION_SCHEMA.TABLES returns one row for each table in the current database for which the current user has permissions.

The following query, therefore, will return the number of tables in the specified database:

USE MyDatabase

As of SQL Server 2008, you can also use sys.tables to count the the number of tables.

From the Microsoft sys.tables Documentation:

sys.tables returns a row for each user table in SQL Server.

The following query will also return the number of table in your database:

FROM sys.tables

Mongodb: failed to connect to server on first connect

Adding one more answer as the solution is from different contexts:

MongoDb Atlas problem solution

I connected to MongoDB Atlas and whitelisted my machine's IP by following the below steps:

  • Go to the security tab

the security tab

  • Go to the network access tab under the security tab

network access tab under security tab

  • Go to the IP whitelist tab

IP whitelist tab

receiver type *** for instance message is a forward declaration

FWIW, I got this error when I was implementing core data in to an existing project. It turned out I forgot to link CoreData.h to my project. I had already added the CoreData framework to my project but solved the issue by linking to the framework in my pre-compiled header just like Apple's templates do:

#import <Availability.h>

#ifndef __IPHONE_5_0
#warning "This project uses features only available in iOS SDK 5.0 and later."

#ifdef __OBJC__
    #import <UIKit/UIKit.h>
    #import <Foundation/Foundation.h>
    #import <CoreData/CoreData.h>

What is the correct syntax for 'else if'?

def function(a):
    if a == '1':
        print ('1a')
    elif a == '2':
        print ('2a')
        print ('3a')

How to create a toggle button in Bootstrap

If you want to keep a small code base, and you are only going to be needing the toggle button for a small part of the application. I would suggest instead maintain you're javascript code your self (angularjs, javascript, jquery) and just use plain CSS.

Good toggle button generator:

How to get client IP address using jQuery

<html lang="en">
    <title>Jquery - get ip address</title>
    <script type="text/javascript" src="//"></script>

<h1>Your Ip Address : <span class="ip"></span></h1>

<script type="text/javascript">
    $.getJSON("", function (data) {


How to change root logging level programmatically for logback

using logback 1.1.3 I had to do the following (Scala code):

import ch.qos.logback.classic.Logger
import org.slf4j.LoggerFactory    
val root: Logger = LoggerFactory.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME).asInstanceOf[Logger] function

This is a variable jQuery uses internally, but had no reason to hide, so it's there to use. Just a heads up, it becomes next release. There's no documentation because it's exposed but not in the official API, lots of things are like this actually, like jQuery.cache (where all of goes).

I'm guessing here by actual usage in the library, it seems to be there exclusively to support $.ajaxStart() and $.ajaxStop() (which I'll explain further), but they only care if it's 0 or not when a request starts or stops. But, since there's no reason to hide it, it's exposed to you can see the actual number of simultaneous AJAX requests currently going on.

When jQuery starts an AJAX request, this happens:

if ( && ! ) {
  jQuery.event.trigger( "ajaxStart" );

This is what causes the $.ajaxStart() event to fire, the number of connections just went from 0 to 1 ( isn't 0 after this one, and !0 == true), this means the first of the current simultaneous requests started. The same thing happens at the other end. When an AJAX request stops (because of a beforeSend abort via return false or an ajax call complete function runs):

if ( && ! ) {
  jQuery.event.trigger( "ajaxStop" );

This is what causes the $.ajaxStop() event to fire, the number of requests went down to 0, meaning the last simultaneous AJAX call finished. The other global AJAX handlers fire in there along the way as well.

Why Response.Redirect causes System.Threading.ThreadAbortException?

This is just how Response.Redirect(url, true) works. It throws the ThreadAbortException to abort the thread. Just ignore that exception. (I presume it is some global error handler/logger where you see it?)

An interesting related discussion Is Response.End() Considered Harmful?.

Data access object (DAO) in Java

Data Access Object Pattern or DAO pattern is used to separate low level data accessing API or operations from high level business services. Following are the participants in Data Access Object Pattern.

Data Access Object Interface - This interface defines the standard operations to be performed on a model object(s).

Data Access Object concrete class -This class implements above interface. This class is responsible to get data from a datasource which can be database / xml or any other storage mechanism.

Model Object or Value Object - This object is simple POJO containing get/set methods to store data retrieved using DAO class.

Sample code here..

raw_input function in Python

raw_input() was renamed to input() in Python 3.


Check if a variable exists in a list in Bash

If it isn't too long; you can just string them between equality along a logical OR comparison like so.

if [ $ITEM == "item1" -o $ITEM == "item2" -o $ITEM == "item3" ]; then
    echo In the list

I had this exact problem and while the above is ugly it is more obvious what is going on than the other generalized solutions.

Rounding SQL DateTime to midnight

In SQL Server 2008 and newer you can cast the DateTime to a Date, which removes the time element.

WHERE Orders.OrderStatus = 'Shipped'  
AND Orders.ShipDate >= (cast(GETDATE()-6 as date))  

In SQL Server 2005 and below you can use:

WHERE Orders.OrderStatus = 'Shipped'  
AND Orders.ShipDate >= DateAdd(Day, Datediff(Day,0, GetDate() -6), 0)

Firebase FCM notifications click_action payload

If your app is in background, Firebase will not trigger onMessageReceived(). Why.....? I have no idea. In this situation, I do not see any point in implementing FirebaseMessagingService.

According to docs, if you want to process background message arrival, you have to send 'click_action' with your message. But it is not possible if you send message from Firebase console, only via Firebase API. It means you will have to build your own "console" in order to enable marketing people to use it. So, this makes Firebase console also quite useless!

There is really good, promising, idea behind this new tool, but executed badly.

I suppose we will have to wait for new versions and improvements/fixes!

You need to install postgresql-server-dev-X.Y for building a server-side extension or libpq-dev for building a client-side application

For me this simple command solved the problem:

sudo apt-get install postgresql postgresql-contrib libpq-dev python-dev

Then I can do:

 pip install psycopg2

SQL Server: Invalid Column Name

  • Refresh your tables.
  • Restart the SQL server.
  • Look out for the spelling mistakes in Query.

Java Calendar, getting current month value, clarification needed


is zero based, 10 is November. From the javadoc;

public static final int MONTH Field number for get and set indicating the month. This is a calendar-specific value. The first month of the year in the Gregorian and Julian calendars is JANUARY which is 0; the last depends on the number of months in a year.


is not a sensible thing to do, the value for JANUARY is 0, which is the same as ERA, you are effectively calling;


how to change language for DataTable

There are language files uploaded in a CDN on the dataTables website So you only have to replace "Spanish" with whatever language you are using in the following example.

$('table.dataTable').DataTable( {
    language: {
        url: '//'

How do I check if a column is empty or null in MySQL?

I hate messy fields in my databases. If the column might be a blank string or null, I'd rather fix this before doing the select each time, like this:

UPDATE MyTable SET MyColumn=NULL WHERE MyColumn='';

This keeps the data tidy, as long as you don't specifically need to differentiate between NULL and empty for some reason.

Datagridview full row selection but get single cell value

Use Cell Click as other methods mentioned will fire upon data binding, not useful if you want the selected value, then the form to close.

private void dgvProducts_CellClick(object sender, DataGridViewCellEventArgs e)
    if (dgvProducts.SelectedCells.Count > 0) // Checking to see if any cell is selected
        int mSelectedRowIndex = dgvProducts.SelectedCells[0].RowIndex;

        DataGridViewRow mSelectedRow = dgvProducts.Rows[mSelectedRowIndex];

        string mCatagoryName = Convert.ToString(mSelectedRow.Cells[1].Value);

        SomeOtherMethod(mProductName); // Passing the name to where ever you need it


Iterator invalidation rules

C++17 (All references are from the final working draft of CPP17 - n4659)


Sequence Containers

  • vector: The functions insert, emplace_back, emplace, push_back cause reallocation if the new size is greater than the old capacity. Reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. If no reallocation happens, all the iterators and references before the insertion point remain valid. []
    With respect to the reserve function, reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. No reallocation shall take place during insertions that happen after a call to reserve() until the time when an insertion would make the size of the vector greater than the value of capacity(). []

  • deque: An insertion in the middle of the deque invalidates all the iterators and references to elements of the deque. An insertion at either end of the deque invalidates all the iterators to the deque, but has no effect on the validity of references to elements of the deque. []

  • list: Does not affect the validity of iterators and references. If an exception is thrown there are no effects. [].
    The insert, emplace_front, emplace_back, emplace, push_front, push_back functions are covered under this rule.

  • forward_list: None of the overloads of insert_after shall affect the validity of iterators and references []

  • array: As a rule, iterators to an array are never invalidated throughout the lifetime of the array. One should take note, however, that during swap, the iterator will continue to point to the same array element, and will thus change its value.

Associative Containers

  • All Associative Containers: The insert and emplace members shall not affect the validity of iterators and references to the container [26.2.6/9]

Unordered Associative Containers

  • All Unordered Associative Containers: Rehashing invalidates iterators, changes ordering between elements, and changes which buckets elements appear in, but does not invalidate pointers or references to elements. [26.2.7/9]
    The insert and emplace members shall not affect the validity of references to container elements, but may invalidate all iterators to the container. [26.2.7/14]
    The insert and emplace members shall not affect the validity of iterators if (N+n) <= z * B, where N is the number of elements in the container prior to the insert operation, n is the number of elements inserted, B is the container’s bucket count, and z is the container’s maximum load factor. [26.2.7/15]

  • All Unordered Associative Containers: In case of a merge operation (e.g., a.merge(a2)), iterators referring to the transferred elements and all iterators referring to a will be invalidated, but iterators to elements remaining in a2 will remain valid. (Table 91 — Unordered associative container requirements)

Container Adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container


Sequence Containers

  • vector: The functions erase and pop_back invalidate iterators and references at or after the point of the erase. []

  • deque: An erase operation that erases the last element of a deque invalidates only the past-the-end iterator and all iterators and references to the erased elements. An erase operation that erases the first element of a deque but not the last element invalidates only iterators and references to the erased elements. An erase operation that erases neither the first element nor the last element of a deque invalidates the past-the-end iterator and all iterators and references to all the elements of the deque. [ Note: pop_front and pop_back are erase operations. —end note ] []

  • list: Invalidates only the iterators and references to the erased elements. []. This applies to erase, pop_front, pop_back, clear functions.
    remove and remove_if member functions: Erases all the elements in the list referred by a list iterator i for which the following conditions hold: *i == value, pred(*i) != false. Invalidates only the iterators and references to the erased elements [].
    unique member function - Erases all but the first element from every consecutive group of equal elements referred to by the iterator i in the range [first + 1, last) for which *i == *(i-1) (for the version of unique with no arguments) or pred(*i, *(i - 1)) (for the version of unique with a predicate argument) holds. Invalidates only the iterators and references to the erased elements. []

  • forward_list: erase_after shall invalidate only iterators and references to the erased elements. [].
    remove and remove_if member functions - Erases all the elements in the list referred by a list iterator i for which the following conditions hold: *i == value (for remove()), pred(*i) is true (for remove_if()). Invalidates only the iterators and references to the erased elements. [].
    unique member function - Erases all but the first element from every consecutive group of equal elements referred to by the iterator i in the range [first + 1, last) for which *i == *(i-1) (for the version with no arguments) or pred(*i, *(i - 1)) (for the version with a predicate argument) holds. Invalidates only the iterators and references to the erased elements. []

  • All Sequence Containers: clear invalidates all references, pointers, and iterators referring to the elements of a and may invalidate the past-the-end iterator (Table 87 — Sequence container requirements). But for forward_list, clear does not invalidate past-the-end iterators. []

  • All Sequence Containers: assign invalidates all references, pointers and iterators referring to the elements of the container. For vector and deque, also invalidates the past-the-end iterator. (Table 87 — Sequence container requirements)

Associative Containers

  • All Associative Containers: The erase members shall invalidate only iterators and references to the erased elements [26.2.6/9]

  • All Associative Containers: The extract members invalidate only iterators to the removed element; pointers and references to the removed element remain valid [26.2.6/10]

Container Adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container

General container requirements relating to iterator invalidation:

  • Unless otherwise specified (either explicitly or by defining a function in terms of other functions), invoking a container member function or passing a container as an argument to a library function shall not invalidate iterators to, or change the values of, objects within that container. [26.2.1/12]

  • no swap() function invalidates any references, pointers, or iterators referring to the elements of the containers being swapped. [ Note: The end() iterator does not refer to any element, so it may be invalidated. —end note ] [26.2.1/(11.6)]

As examples of the above requirements:

  • transform algorithm: The op and binary_op functions shall not invalidate iterators or subranges, or modify elements in the ranges [28.6.4/1]

  • accumulate algorithm: In the range [first, last], binary_op shall neither modify elements nor invalidate iterators or subranges [29.8.2/1]

  • reduce algorithm: binary_op shall neither invalidate iterators or subranges, nor modify elements in the range [first, last]. [29.8.3/5]

and so on...

Getting path of captured image in Android using camera intent

Here I updated the sample code in Kotlin. Please note on Nougat and above version Uri.fromFile(file) is not working and it crashes the app for that need to implement FileProvider which is safest way to send files from intent. For implementing this refer this answer or this article

private fun takePhotoFromCamera() {
        val isDeviceSupportCamera: Boolean = this.packageManager.hasSystemFeature(PackageManager.FEATURE_CAMERA)
        if (isDeviceSupportCamera) {
            val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)

            if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
                file = File(getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS + "/attachments")!!.path,
                        System.currentTimeMillis().toString() + ".jpg")
//            fileUri = Uri.fromFile(file)
                fileUri = FileProvider.getUriForFile(this, this.applicationContext.packageName + ".provider", file!!)
                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri)
                if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP) {
                startActivityForResult(takePictureIntent, Constants.REQUEST_CODE_IMAGE_CAPTURE)

        } else {
            Toast.makeText(this, this.getString(R.string.camera_not_supported), Toast.LENGTH_SHORT).show()

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        if (resultCode == Activity.RESULT_OK) {
             if(requestCode == Constants.REQUEST_CODE_IMAGE_CAPTURE) {
                realPath = file?.path
                 //do what ever you want to do

SELECT *, COUNT(*) in SQLite

count(*) is an aggregate function. Aggregate functions need to be grouped for a meaningful results. You can read: count columns group by

Using Auto Layout in UITableView for dynamic cell layouts & variable row heights

Let's say you have a cell with a subview, and you want the cell's height to be high enough to encompass the subview + padding.

1) Set the subview's bottom constraint equal to the cell.contentView minus the padding you want. Do not set constraints on the cell or cell.contentView itself.

2) Set either the tableView's rowHeight property or tableView:heightForRowAtIndexPath: to UITableViewAutomaticDimension.

3) Set either the tableView's estimatedRowHeight property or tableView:estimatedHeightForRowAtIndexPath: to a best guess of the height.

That's it.

super() raises "TypeError: must be type, not classobj" for new-style class

the correct way to do will be as following in the old-style classes which doesn't inherit from 'object'

class A:
    def foo(self):
        return "Hi there"

class B(A):
    def foo(self, name):
        return + name

How to add row of data to Jtable from values received from jtextfield and comboboxes

String[] tblHead={"Item Name","Price","Qty","Discount"};
DefaultTableModel dtm=new DefaultTableModel(tblHead,0);
JTable tbl=new JTable(dtm);
String[] item={"A","B","C","D"};

Here;this is the solution.

Extract the last substring from a cell

Try this:

Right(RC[-1],Len(RC[-1])-InStrRev(RC[-1]," "))

Only detect click event on pseudo-element

This works for me:

$('#element').click(function (e) {
        if (e.offsetX > {
            // click on element
           // click on ::before element

What is the MySQL JDBC driver connection string?

String url = "jdbc:mysql://localhost:3306/dbname";
String user = "user";
String pass = "pass";
Class.forName ("com.mysql.jdbc.Driver").newInstance ();
Connection conn = DriverManager.getConnection (url, user, pass);

3306 is the default port for mysql.

If you are using Java 7 then there is no need to even add the Class.forName("com.mysql.jdbc.Driver").newInstance (); statement.Automatic Resource Management (ARM) is added in JDBC 4.1 which comes by default in Java 7.

The general format for a JDBC URL for connecting to a MySQL server is as follows, with items in square brackets ([ ]) being optional:

jdbc:mysql://[host1][:port1][,[host2][:port2]]...[/[database]] »

In, how to get the column names from a datatable

' i modify the code for Datatable 

For Each c as DataColumn in dt.Columns
 For j=0 To _dataTable.Columns.Count-1
            xlWorksheet.Cells (i+1, j+1) = _dataTable.Columns(j).ColumnName

Hope this could be help!

Python virtualenv questions

in my project file i have this code (it works with virtualenv,django,apache2 in windows and python 3.4)

import os
import sys
DJANGO_PATH = os.path.join(os.path.abspath(os.path.dirname(__file__)),'..')
activate_this = 'c:/myproject/env/scripts/'
from django.core.wsgi import get_wsgi_application
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "myproject.settings")
application = get_wsgi_application()

in virtualhost file conf i have

<VirtualHost *:80>
    ServerName mysite
    WSGIScriptAlias / c:/myproject/myproject/myproject/
    DocumentRoot c:/myproject/myproject/
    <Directory  "c:/myproject/myproject/myproject/">
       Options +Indexes +FollowSymLinks +MultiViews
       AllowOverride All
      Require local

ORA-06508: PL/SQL: could not find program unit being called

I suspect you're only reporting the last error in a stack like this:

ORA-04068: existing state of packages has been discarded
ORA-04061: existing state of package body "schema.package" has been invalidated
ORA-04065: not executed, altered or dropped package body "schema.package"
ORA-06508: PL/SQL: could not find program unit being called: "schema.package"

If so, that's because your package is stateful:

The values of the variables, constants, and cursors that a package declares (in either its specification or body) comprise its package state. If a PL/SQL package declares at least one variable, constant, or cursor, then the package is stateful; otherwise, it is stateless.

When you recompile the state is lost:

If the body of an instantiated, stateful package is recompiled (either explicitly, with the "ALTER PACKAGE Statement", or implicitly), the next invocation of a subprogram in the package causes Oracle Database to discard the existing package state and raise the exception ORA-04068.

After PL/SQL raises the exception, a reference to the package causes Oracle Database to re-instantiate the package, which re-initializes it...

You can't avoid this if your package has state. I think it's fairly rare to really need a package to be stateful though, so you should revisit anything you have declared in the package, but outside a function or procedure, to see if it's really needed at that level. Since you're on 10g though, that includes constants, not just variables and cursors.

But the last paragraph from the quoted documentation means that the next time you reference the package in the same session, you won't get the error and it will work as normal (until you recompile again).

How do I delete an exported environment variable?

this may also work.


How to adjust text font size to fit textview

Google already made this feature.

    android:autoSizeTextType="uniform" />