Programs & Examples On #Abcpdf

ABCpdf is WebSupergoo's software component for generating and manipulating PDF documents dynamically on Windows based systems, supporting the Microsoft .NET Framework and ASP/COM.

AngularJS $watch window resize inside directive

You shouldn't need a $watch. Just bind to resize event on window:


'use strict';

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

app.directive('myDirective', ['$window', function ($window) {

     return {
        link: link,
        restrict: 'E',
        template: '<div>window size: {{width}}px</div>'

     function link(scope, element, attrs){

       scope.width = $window.innerWidth;

       angular.element($window).bind('resize', function(){

         scope.width = $window.innerWidth;

         // manuall $digest required as resize event
         // is outside of angular



How To Upload Files on GitHub

If you want to upload a folder or a file to Github

1- Create a repository on the Github

2- make: git remote add origin "Your Link" as it is described on the Github

3- Then use git push -u origin master.

4- You have to enter your username and Password.

5- After the authentication, the transfer will start

How to sleep the thread in node.js without affecting other threads?

If you are referring to the npm module sleep, it notes in the readme that sleep will block execution. So you are right - it isn't what you want. Instead you want to use setTimeout which is non-blocking. Here is an example:

setTimeout(function() {
  console.log('hello world!');
}, 5000);

For anyone looking to do this using es7 async/await, this example should help:

const snooze = ms => new Promise(resolve => setTimeout(resolve, ms));

const example = async () => {
  console.log('About to snooze without halting the event loop...');
  await snooze(1000);


MySQL Removing Some Foreign keys

The foreign keys are there to ensure data integrity, so you can't drop a column as long as it's part of a foreign key. You need to drop the key first.

I would think the following query would do it:

ALTER TABLE assignmentStuff DROP FOREIGN KEY assignmentIDX;

How to install php-curl in Ubuntu 16.04

In Ubuntu 16.04 default PHP version is 7.0, if you want to use different version then you need to install PHP package according to PHP version:

  • PHP 7.4: sudo apt-get install php7.4-curl
  • PHP 7.3: sudo apt-get install php7.3-curl
  • PHP 7.2: sudo apt-get install php7.2-curl
  • PHP 7.1: sudo apt-get install php7.1-curl
  • PHP 7.0: sudo apt-get install php7.0-curl
  • PHP 5.6: sudo apt-get install php5.6-curl
  • PHP 5.5: sudo apt-get install php5.5-curl

Return the characters after Nth character in a string

Mid(strYourString, 4) (i.e. without the optional length argument) will return the substring starting from the 4th character and going to the end of the string.

Calling a phone number in swift

Swift 3.0 solution:

let formatedNumber = phone.components(separatedBy: NSCharacterSet.decimalDigits.inverted).joined(separator: "")
print("calling \(formatedNumber)")
let phoneUrl = "tel://\(formatedNumber)"
let url:URL = URL(string: phoneUrl)!

Django: List field in model?

If you're on Django 1.10 or newer AND Postgres as your database, you can use ArrayField. It's better to use than django-taggit or other alternatives, as it's native to the Django framework.

from django.db import models
from django.contrib.postgres.fields import ArrayField

class ChessBoard(models.Model):
    board = ArrayField(
            models.CharField(max_length=10, blank=True),

If you're on Django 3.1 or newer they've added support for JSONField with most database backends (MariaDB 10.2.7+, MySQL 5.7.8+, Oracle, PostgreSQL, and SQLite 3.9.0+). You can use this to store your Array!

from django.db import models

class ChessBoard(models.Model):
    list_of_pieces = models.JSONField()

How to draw border around a UILabel?

Using an NSAttributedString string for your labels attributedText is probably your best bet. Check out this example.

summing two columns in a pandas dataframe

I think you've misunderstood some python syntax, the following does two assignments:

In [11]: a = b = 1

In [12]: a
Out[12]: 1

In [13]: b
Out[13]: 1

So in your code it was as if you were doing:

sum = df['budget'] + df['actual']  # a Series
# and
df['variance'] = df['budget'] + df['actual']  # assigned to a column

The latter creates a new column for df:

In [21]: df
  cluster                 date  budget  actual
0       a  2014-01-01 00:00:00   11000   10000
1       a  2014-02-01 00:00:00    1200    1000
2       a  2014-03-01 00:00:00     200     100
3       b  2014-04-01 00:00:00     200     300
4       b  2014-05-01 00:00:00     400     450
5       c  2014-06-01 00:00:00     700    1000
6       c  2014-07-01 00:00:00    1200    1000
7       c  2014-08-01 00:00:00     200     100
8       c  2014-09-01 00:00:00     200     300

In [22]: df['variance'] = df['budget'] + df['actual']

In [23]: df
  cluster                 date  budget  actual  variance
0       a  2014-01-01 00:00:00   11000   10000     21000
1       a  2014-02-01 00:00:00    1200    1000      2200
2       a  2014-03-01 00:00:00     200     100       300
3       b  2014-04-01 00:00:00     200     300       500
4       b  2014-05-01 00:00:00     400     450       850
5       c  2014-06-01 00:00:00     700    1000      1700
6       c  2014-07-01 00:00:00    1200    1000      2200
7       c  2014-08-01 00:00:00     200     100       300
8       c  2014-09-01 00:00:00     200     300       500

As an aside, you shouldn't use sum as a variable name as the overrides the built-in sum function.

Python - List of unique dictionaries

a = [
{'id':1,'name':'john', 'age':34},
{'id':1,'name':'john', 'age':34},
{'id':2,'name':'hanna', 'age':30},

b = {x['id']:x for x in a}.values()



[{'age': 34, 'id': 1, 'name': 'john'}, {'age': 30, 'id': 2, 'name': 'hanna'}]

How do I use Access-Control-Allow-Origin? Does it just go in between the html head tags?

If you use Java and spring MVC you just need to add the following annotation to your method returning your page :

@CrossOrigin(origins = "*")

"*" is to allow your page to be accessible from anywhere. See for more details about that.

How Does Modulus Divison Work

Very simple: a % b is defined as the remainder of the division of a by b.

See the wikipedia article for more examples.

Error: Main method not found in class Calculate, please define the main method as: public static void main(String[] args)

My suggestions :

  • Keep the program modular. Keep the Calculate class in a separate file and create a new class that calls the main method. This would make the code readable.
  • For setting the values in the number, use constructors. Do not use like the methods you have used above like :

    public void setNumber(double fnum, double snum){ this.fn = fnum; = snum; }

    Constructors exists to initialize the objects.This is their job and they are pretty good at it.

  • Getters for members of Calculate class seem in place. But setters are not. Getters and setters serves as one important block in the bridge of efficient programming with java. Put setters for fnum and snum as well

  • In the main class, create a Calculate object using the new operator and the constructor in place.

  • Call the getAnswer() method with the created Calculate object.

Rest of the code looks fine to me. Be modular. You could read your program in a much better way.

Here is my modular piece of code. Two files : &

public class Calculate {

private double fn;
private double sn;
private char op;

    public double getFn() {
        return fn;

    public void setFn(double fn) {
        this.fn = fn;

    public double getSn() {
        return sn;

    public void setSn(double sn) { = sn;

    public char getOp() {
        return op;

    public void setOp(char op) {
        this.op = op;

    public Calculate(double fn, double sn, char op) {
        this.fn = fn; = sn;
        this.op = op;

public void getAnswer(){
    double ans;
    switch (getOp()){
        case '+': 
            ans = add(getFn(), getSn());
        case '-': 
            ans = sub (getFn(), getSn());
        case '*': 
            ans = mul (getFn(), getSn());
        case '/': 
            ans = div (getFn(), getSn());
            System.out.println("Invalid choice of operator");
    public static double add(double x,double y){
        return x + y;
    public static double sub(double x, double y){
        return x - y;
    public static double mul(double x, double y){
        return x * y;
    public static double div(double x, double y){
        return x / y;

    public static void ansOutput(double x){
        System.out.println("----------- -------");
        System.out.printf("the answer is %.2f\n", x);

public class Main {
    public static void main(String args[])
        Calculate obj = new Calculate(1,2,'+');

Check if a number is a perfect square

If youre interested, I have a pure-math response to a similar question at math stackexchange, "Detecting perfect squares faster than by extracting square root".

My own implementation of isSquare(n) may not be the best, but I like it. Took me several months of study in math theory, digital computation and python programming, comparing myself to other contributors, etc., to really click with this method. I like its simplicity and efficiency though. I havent seen better. Tell me what you think.

def isSquare(n):
    ## Trivial checks
    if type(n) != int:  ## integer
        return False
    if n < 0:      ## positivity
        return False
    if n == 0:      ## 0 pass
        return True

    ## Reduction by powers of 4 with bit-logic
    while n&3 == 0:    

    ## Simple bit-logic test. All perfect squares, in binary,
    ## end in 001, when powers of 4 are factored out.
    if n&7 != 1:
        return False

    if n==1:
        return True  ## is power of 4, or even power of 2

    ## Simple modulo equivalency test
    c = n%10
    if c in {3, 7}:
        return False  ## Not 1,4,5,6,9 in mod 10
    if n % 7 in {3, 5, 6}:
        return False  ## Not 1,2,4 mod 7
    if n % 9 in {2,3,5,6,8}:
        return False  
    if n % 13 in {2,5,6,7,8,11}:
        return False  

    ## Other patterns
    if c == 5:  ## if it ends in a 5
        if (n//10)%10 != 2:
            return False    ## then it must end in 25
        if (n//100)%10 not in {0,2,6}: 
            return False    ## and in 025, 225, or 625
        if (n//100)%10 == 6:
            if (n//1000)%10 not in {0,5}:
                return False    ## that is, 0625 or 5625
        if (n//10)%4 != 0:
            return False    ## (4k)*10 + (1,9)

    ## Babylonian Algorithm. Finding the integer square root.
    ## Root extraction.
    s = (len(str(n))-1) // 2
    x = (10**s) * 4

    A = {x, n}
    while x * x != n:
        x = (x + (n // x)) >> 1
        if x in A:
            return False
    return True

Pretty straight forward. First it checks that we have an integer, and a positive one at that. Otherwise there is no point. It lets 0 slip through as True (necessary or else next block is infinite loop).

The next block of code systematically removes powers of 4 in a very fast sub-algorithm using bit shift and bit logic operations. We ultimately are not finding the isSquare of our original n but of a k<n that has been scaled down by powers of 4, if possible. This reduces the size of the number we are working with and really speeds up the Babylonian method, but also makes other checks faster too.

The third block of code performs a simple Boolean bit-logic test. The least significant three digits, in binary, of any perfect square are 001. Always. Save for leading zeros resulting from powers of 4, anyway, which has already been accounted for. If it fails the test, you immediately know it isnt a square. If it passes, you cant be sure.

Also, if we end up with a 1 for a test value then the test number was originally a power of 4, including perhaps 1 itself.

Like the third block, the fourth tests the ones-place value in decimal using simple modulus operator, and tends to catch values that slip through the previous test. Also a mod 7, mod 8, mod 9, and mod 13 test.

The fifth block of code checks for some of the well-known perfect square patterns. Numbers ending in 1 or 9 are preceded by a multiple of four. And numbers ending in 5 must end in 5625, 0625, 225, or 025. I had included others but realized they were redundant or never actually used.

Lastly, the sixth block of code resembles very much what the top answerer - Alex Martelli - answer is. Basically finds the square root using the ancient Babylonian algorithm, but restricting it to integer values while ignoring floating point. Done both for speed and extending the magnitudes of values that are testable. I used sets instead of lists because it takes far less time, I used bit shifts instead of division by two, and I smartly chose an initial start value much more efficiently.

By the way, I did test Alex Martelli's recommended test number, as well as a few numbers many orders magnitude larger, such as:

x=1000199838770766116385386300483414671297203029840113913153824086810909168246772838680374612768821282446322068401699727842499994541063844393713189701844134801239504543830737724442006577672181059194558045164589783791764790043104263404683317158624270845302200548606715007310112016456397357027095564872551184907513312382763025454118825703090010401842892088063527451562032322039937924274426211671442740679624285180817682659081248396873230975882215128049713559849427311798959652681930663843994067353808298002406164092996533923220683447265882968239141724624870704231013642255563984374257471112743917655991279898690480703935007493906644744151022265929975993911186879561257100479593516979735117799410600147341193819147290056586421994333004992422258618475766549646258761885662783430625 ** 2
for i in range(x, x+2):
    print(i, isSquare(i))

printed the following results:

1000399717477066534083185452789672211951514938424998708930175541558932213310056978758103599452364409903384901149641614494249195605016959576235097480592396214296565598519295693079257885246632306201885850365687426564365813280963724310434494316592041592681626416195491751015907716210235352495422858432792668507052756279908951163972960239286719854867504108121432187033786444937064356645218196398775923710931242852937602515835035177768967470757847368349565128635934683294155947532322786360581473152034468071184081729335560769488880138928479829695277968766082973795720937033019047838250608170693879209655321034310764422462828792636246742456408134706264621790736361118589122797268261542115823201538743148116654378511916000714911467547209475246784887830649309238110794938892491396597873160778553131774466638923135932135417900066903068192088883207721545109720968467560224268563643820599665232314256575428214983451466488658896488012211237139254674708538347237589290497713613898546363590044902791724541048198769085430459186735166233549186115282574626012296888817453914112423361525305960060329430234696000121420787598967383958525670258016851764034555105019265380321048686563527396844220047826436035333266263375049097675787975100014823583097518824871586828195368306649956481108708929669583308777347960115138098217676704862934389659753628861667169905594181756523762369645897154232744410732552956489694024357481100742138381514396851789639339362228442689184910464071202445106084939268067445115601375050153663645294106475257440167535462278022649865332161044187890625 True
1000399717477066534083185452789672211951514938424998708930175541558932213310056978758103599452364409903384901149641614494249195605016959576235097480592396214296565598519295693079257885246632306201885850365687426564365813280963724310434494316592041592681626416195491751015907716210235352495422858432792668507052756279908951163972960239286719854867504108121432187033786444937064356645218196398775923710931242852937602515835035177768967470757847368349565128635934683294155947532322786360581473152034468071184081729335560769488880138928479829695277968766082973795720937033019047838250608170693879209655321034310764422462828792636246742456408134706264621790736361118589122797268261542115823201538743148116654378511916000714911467547209475246784887830649309238110794938892491396597873160778553131774466638923135932135417900066903068192088883207721545109720968467560224268563643820599665232314256575428214983451466488658896488012211237139254674708538347237589290497713613898546363590044902791724541048198769085430459186735166233549186115282574626012296888817453914112423361525305960060329430234696000121420787598967383958525670258016851764034555105019265380321048686563527396844220047826436035333266263375049097675787975100014823583097518824871586828195368306649956481108708929669583308777347960115138098217676704862934389659753628861667169905594181756523762369645897154232744410732552956489694024357481100742138381514396851789639339362228442689184910464071202445106084939268067445115601375050153663645294106475257440167535462278022649865332161044187890626 False

And it did this in 0.33 seconds.

In my opinion, my algorithm works the same as Alex Martelli's, with all the benefits thereof, but has the added benefit highly efficient simple-test rejections that save a lot of time, not to mention the reduction in size of test numbers by powers of 4, which improves speed, efficiency, accuracy and the size of numbers that are testable. Probably especially true in non-Python implementations.

Roughly 99% of all integers are rejected as non-Square before Babylonian root extraction is even implemented, and in 2/3 the time it would take the Babylonian to reject the integer. And though these tests dont speed up the process that significantly, the reduction in all test numbers to an odd by dividing out all powers of 4 really accelerates the Babylonian test.

I did a time comparison test. I tested all integers from 1 to 10 Million in succession. Using just the Babylonian method by itself (with my specially tailored initial guess) it took my Surface 3 an average of 165 seconds (with 100% accuracy). Using just the logical tests in my algorithm (excluding the Babylonian), it took 127 seconds, it rejected 99% of all integers as non-Square without mistakenly rejecting any perfect squares. Of those integers that passed, only 3% were perfect Squares (a much higher density). Using the full algorithm above that employs both the logical tests and the Babylonian root extraction, we have 100% accuracy, and test completion in only 14 seconds. The first 100 Million integers takes roughly 2 minutes 45 seconds to test.

EDIT: I have been able to bring down the time further. I can now test the integers 0 to 100 Million in 1 minute 40 seconds. A lot of time is wasted checking the data type and the positivity. Eliminate the very first two checks and I cut the experiment down by a minute. One must assume the user is smart enough to know that negatives and floats are not perfect squares.

Swipe ListView item From right to left show delete button

I just got his working using the ViewSwitcher in a ListItem.


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""
android:orientation="horizontal" >

    android:measureAllChildren="false" >
        android:paddingLeft="10dp" />




In the ListAdapter: Implement OnclickListeners for the Edit and Delete button in the getView() method. The catch here is to get the position of the ListItem clicked inside the onClick methods. setTag() and getTag() methods are used for this.

public View getView(final int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    final ViewHolder viewHolder;
    if (convertView == null) {
        viewHolder = new ViewHolder();
        convertView = mInflater.inflate(R.layout.list_item, null);
        viewHolder.itemName = (TextView) convertView
        viewHolder.deleteItem.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub

        viewHolder.editItem.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub
} else {
        viewHolder = (ViewHolder) convertView.getTag();

return convertView;  

In the Fragment, Add a Gesture Listener to detect the Fling Gesture:

public class MyGestureListener extends SimpleOnGestureListener {
    private ListView list;

    public MyGestureListener(ListView list) {
        this.list = list;


    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {

        if (showDeleteButton(e1))
            return true;
        return super.onFling(e1, e2, velocityX, velocityY);

    public boolean onScroll(MotionEvent e1, MotionEvent e2,
            float distanceX, float distanceY) {
        // TODO Auto-generated method stub
        return super.onScroll(e1, e2, distanceX, distanceY);

    private boolean showDeleteButton(MotionEvent e1) {
        int pos = list.pointToPosition((int) e1.getX(), (int) e1.getY());
        return showDeleteButton(pos);

    private boolean showDeleteButton(int pos) {

        View child = list.getChildAt(pos);
        if (child != null) {
            Button delete = (Button) child
            ViewSwitcher viewSwitcher = (ViewSwitcher) child
            TextView hostName = (TextView) child
            if (delete != null) {
                    viewSwitcher.setInAnimation(AnimationUtils.loadAnimation(getActivity(), R.anim.slide_in_left));
                    viewSwitcher.setOutAnimation(AnimationUtils.loadAnimation(getActivity(), R.anim.slide_out_right));

                // frameLayout.setVisibility(View.VISIBLE);
            return true;
        return false;

In the onCreateView method of the Fragment,

GestureDetector gestureDetector = new GestureDetector(getActivity(),
            new MyGestureListener(hostList));
    hostList.setOnTouchListener(new View.OnTouchListener() {

        public boolean onTouch(View v, MotionEvent event) {
            // TODO Auto-generated method stub
            if (gestureDetector.onTouchEvent(event)) {
                return true;
            } else {
                return false;


This worked for me. Should refine it more.

ERROR Error: No value accessor for form control with unspecified name attribute on switch

In my case i used directive, but hadn't imported it in my module.ts file. Import fixed it.

Laravel migration: unique key is too long, even if specified

Set database engine InnoDB:

  Schema::create('users', function (Blueprint $table) {
            $table->engine = 'InnoDB';

Ant if else condition?

The if attribute does not exist for <copy>. It should be applied to the <target>.

Below is an example of how you can use the depends attribute of a target and the if and unless attributes to control execution of dependent targets. Only one of the two should execute.

<target name="prepare-copy" description="copy file based on condition"
    depends="prepare-copy-true, prepare-copy-false">

<target name="prepare-copy-true" description="copy file based on condition"
    <echo>Get file based on condition being true</echo>
    <copy file="${some.dir}/true" todir="." />

<target name="prepare-copy-false" description="copy file based on false condition" 
    <echo>Get file based on condition being false</echo>
    <copy file="${some.dir}/false" todir="." />

If you are using ANT 1.8+, then you can use property expansion and it will evaluate the value of the property to determine the boolean value. So, you could use if="${copy-condition}" instead of if="copy-condition".

In ANT 1.7.1 and earlier, you specify the name of the property. If the property is defined and has any value (even an empty string), then it will evaluate to true.

How to create an exit message

I got here searching for a way to execute some code whenever the program ends.
Found this:

Kernel.at_exit { puts "sayonara" }
# do whatever
# [...]
# call #exit or #abort or just let the program end
# calling #exit! will skip the call

Called multiple times will register multiple handlers.

Open youtube video in Fancybox jquery

This has a regular expression so it's easier to just copy and paste the youtube url. Is great for when you use a CMS for clients.

/*fancybox yt video*/
$(".fancybox-video").click(function() {

    padding: 0,
        'autoScale'     : false,
        'transitionIn'  : 'none',
        'transitionOut' : 'none',
        'title'         : this.title,
        'width'         : 795,
        'height'        : 447,
        'href'          : this.href.replace(new RegExp("watch.*v=","i"), "v/"),
        'type'          : 'swf',
        'swf'           : {
        'wmode'             : 'transparent',
        'allowfullscreen'   : 'true'

    return false;

Why can't overriding methods throw exceptions broader than the overridden method?

The subclass's overriding method can only throw multiple checked exceptions that are subclasses of the superclass's method's checked exception, but cannot throw multiple checked exceptions that are unrelated to the superclass's method's checked exception

Why do I get PLS-00302: component must be declared when it exists?

You can get that error if you have an object with the same name as the schema. For example:

create sequence s2;


ORA-06550: line 2, column 6:
PLS-00302: component 'A' must be declared
ORA-06550: line 2, column 3:
PL/SQL: Statement ignored

When you refer to S2.MY_FUNC2 the object name is being resolved so it doesn't try to evaluate S2 as a schema name. When you just call it as MY_FUNC2 there is no confusion, so it works.

The documentation explains name resolution. The first piece of the qualified object name - S2 here - is evaluated as an object on the current schema before it is evaluated as a different schema.

It might not be a sequence; other objects can cause the same error. You can check for the existence of objects with the same name by querying the data dictionary.

select owner, object_type, object_name
from all_objects
where object_name = 'S2';

Authentication failed because remote party has closed the transport stream

Adding the below code helped me overcome the issue.

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11;

How to make --no-ri --no-rdoc the default for gem install?

On Linux (and probably Mac):

echo 'gem: --no-document' >> ~/.gemrc

This one-liner used to be in comments here, but somehow disappeared.

Launch Bootstrap Modal on page load

regarding what Andre's Ilich say you have to add the js script after the line in what you call the jquery:

<script src="content/bootstrapJS/jquery-2.1.1.min.js" type="text/javascript"></script>

<script type="text/javascript">

in my case that was the problem hope it helps

JQuery html() vs. innerHTML

Given the general support of .innerHTML these days, the only effective difference now is that .html() will execute code in any <script> tags if there are any in the html you give it. .innerHTML, under HTML5, will not.

From the jQuery docs:

By design, any jQuery constructor or method that accepts an HTML string — jQuery(), .append(), .after(), etc. — can potentially execute code. This can occur by injection of script tags or use of HTML attributes that execute code (for example, <img onload="">). Do not use these methods to insert strings obtained from untrusted sources such as URL query parameters, cookies, or form inputs. Doing so can introduce cross-site-scripting (XSS) vulnerabilities. Remove or escape any user input before adding content to the document.

Note: both .innerHTML and .html() can execute js other ways (e.g the onerror attribute).

How to Insert Double or Single Quotes

Easier steps:

  1. Highlight the cells you want to add the quotes.
  2. Go to Format–>Cells–>Custom
  3. Copy/Paste the following into the Type field: \"@\" or \'@\'
  4. Done!

In plain English, what does "git reset" do?

Please be aware, this is a simplified explanation intended as a first step in seeking to understand this complex functionality.

May be helpful for visual learners who want to visualise what their project state looks like after each of these commands:

For those who use Terminal with colour turned on (git config --global color.ui auto):

git reset --soft A and you will see B and C's stuff in green (staged and ready to commit)

git reset --mixed A (or git reset A) and you will see B and C's stuff in red (unstaged and ready to be staged (green) and then committed)

git reset --hard A and you will no longer see B and C's changes anywhere (will be as if they never existed)

Or for those who use a GUI program like 'Tower' or 'SourceTree'

git reset --soft A and you will see B and C's stuff in the 'staged files' area ready to commit

git reset --mixed A (or git reset A) and you will see B and C's stuff in the 'unstaged files' area ready to be moved to staged and then committed

git reset --hard A and you will no longer see B and C's changes anywhere (will be as if they never existed)

Column "invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause"

The consequence of this is that you may need a rather insane-looking query, e. g.,

SELECT [dbo].[tblTimeSheetExportFiles].[lngRecordID]            AS lngRecordID
          ,[dbo].[tblTimeSheetExportFiles].[vcrSourceWorkbookName]  AS vcrSourceWorkbookName
          ,[dbo].[tblTimeSheetExportFiles].[vcrImportFileName]      AS vcrImportFileName
          ,[dbo].[tblTimeSheetExportFiles].[dtmLastWriteTime]       AS dtmLastWriteTime
          ,[dbo].[tblTimeSheetExportFiles].[lngNRecords]            AS lngNRecords
          ,[dbo].[tblTimeSheetExportFiles].[lngSizeOnDisk]          AS lngSizeOnDisk
          ,[dbo].[tblTimeSheetExportFiles].[lngLastIdentity]        AS lngLastIdentity
          ,[dbo].[tblTimeSheetExportFiles].[dtmImportCompletedTime] AS dtmImportCompletedTime
          ,MIN ( [tblTimeRecords].[dtmActivity_Date] )              AS dtmPeriodFirstWorkDate
          ,MAX ( [tblTimeRecords].[dtmActivity_Date] )              AS dtmPeriodLastWorkDate
          ,SUM ( [tblTimeRecords].[decMan_Hours_Actual] )           AS decHoursWorked
          ,SUM ( [tblTimeRecords].[decAdjusted_Hours] )             AS decHoursBilled
      FROM [dbo].[tblTimeSheetExportFiles]
      LEFT JOIN   [dbo].[tblTimeRecords]
              ON  [dbo].[tblTimeSheetExportFiles].[lngRecordID] = [dbo].[tblTimeRecords].[lngTimeSheetExportFile]
        GROUP BY  [dbo].[tblTimeSheetExportFiles].[lngRecordID]

Since the primary table is a summary table, its primary key handles the only grouping or ordering that is truly necessary. Hence, the GROUP BY clause exists solely to satisfy the query parser.

auto run a bat script in windows 7 at login

To run the batch file when the VM user logs in:

Drag the shortcut--the one that's currently on your desktop--(or the batch file itself) to Start - All Programs - Startup. Now when you login as that user, it will launch the batch file.

Another way to do the same thing is to save the shortcut or the batch file in %AppData%\Microsoft\Windows\Start Menu\Programs\Startup\.

As far as getting it to run full screen, it depends a bit what you mean. You can have it launch maximized by editing your batch file like this:

start "" /max "C:\Program Files\Oracle\VirtualBox\VirtualBox.exe" --comment "VM" --startvm "12dada4d-9cfd-4aa7-8353-20b4e455b3fa"

But if VirtualBox has a truly full-screen mode (where it hides even the taskbar), you'll have to look for a command-line parameter on VirtualBox.exe. I'm not familiar with that product.

phonegap open link in browser

<a onclick="'', { openExternal:true });">Link</a>

Works for me with android & PG 3.0

Passing multiple variables to another page in url

Your first variable declartion must start with a ? while any additional must be concatenated with a &

How do I apply a CSS class to Html.ActionLink in ASP.NET MVC?

This syntax worked for me in MVC 3 with Razor:

@Html.ActionLink("Delete", "DeleteList", "List", new { ID = item.ID, ListID = }, new {@class= "delete"})

How to write a multidimensional array to a text file?

Pickle is best for these cases. Suppose you have a ndarray named x_train. You can dump it into a file and revert it back using the following command:

import pickle

###Load into file
with open("myfile.pkl","wb") as f:

###Extract from file
with open("myfile.pkl","rb") as f:
    x_temp = pickle.load(f)

Running Python code in Vim

This .vimrc mapping needs Conque Shell, but it replicates Geany (and other X editors') behaviour:

  • Press a key to execute
  • Executes in gnome-terminal
  • Waits for confirmation to exit
  • Window closes automatically on exit

    :let dummy = conque_term#subprocess('gnome-terminal -e "bash -c \"python ' . expand("%") . '; answer=\\\"z\\\"; while [ $answer != \\\"q\\\" ]; do printf \\\"\nexited with code $?, press (q) to quit: \\\"; read -n 1 answer; done; \" "')

What does the "assert" keyword do?

Assertions are generally used primarily as a means of checking the program's expected behavior. It should lead to a crash in most cases, since the programmer's assumptions about the state of the program are false. This is where the debugging aspect of assertions come in. They create a checkpoint that we simply can't ignore if we would like to have correct behavior.

In your case it does data validation on the incoming parameters, though it does not prevent clients from misusing the function in the future. Especially if they are not, (and should not) be included in release builds.

angularjs getting previous route path

Just to document:

The callback argument previousRoute is having a property called $route which is much similar to the $route service. Unfortunately currentRoute argument, is not having much information about the current route.

To overcome this i have tried some thing like this.

   when('/', {
  when('/menu', {
    routeName:"Site Menu"

Please note that in the above routes config a custom property called routeName is added.$rootScope, $route){
    //Bind the `$routeChangeSuccess` event on the rootScope, so that we dont need to 
    //bind in induvidual controllers.
    $rootScope.$on('$routeChangeSuccess', function(currentRoute, previousRoute) {
        //This will give the custom property that we have defined while configuring the routes.

Get pixel's RGB using PIL

Not PIL, but imageio.imread might still be interesting:

import imageio
im = scipy.misc.imread('um_000000.png', flatten=False, mode='RGB')
im = imageio.imread('Figure_1.png', pilmode='RGB')


(480, 640, 3)

so it is (height, width, channels). So the pixel at position (x, y) is

color = tuple(im[y][x])
r, g, b = color


scipy.misc.imread is deprecated in SciPy 1.0.0 (thanks for the reminder, fbahr!)

How do I implement charts in Bootstrap?

You can use a 3rd party library like Shield UI for charting - that is tested and works well on all legacy and new web browsers and devices.

jQuery Event : Detect changes to the html/text of a div

You can try this

$('.myDiv').bind('DOMNodeInserted DOMNodeRemoved', function() {


but this might not work in internet explorer, haven't tested it

Create a CSS rule / class with jQuery at runtime

You can use this lib called cssobj

var result = cssobj({'#my-window': {
  position: 'fixed',
  zIndex: '102',

Any time you can update your rules like this:

result.obj['#my-window'].display = 'block'

Then you got the rule changed. jQuery is not the lib doing this.

What exactly does the .join() method do?

Look carefully at your output:

^                 ^                 ^

I've highlighted the "5", "9", "5" of your original string. The Python join() method is a string method, and takes a list of things to join with the string. A simpler example might help explain:

>>> ",".join(["a", "b", "c"])

The "," is inserted between each element of the given list. In your case, your "list" is the string representation "595", which is treated as the list ["5", "9", "5"].

It appears that you're looking for + instead:

print array.array('c', random.sample(string.ascii_letters, 20 - len(strid)))
.tostring() + strid

WSDL vs REST Pros and Cons

To me we should be careful when we use the word web service. We should all the time specify if we are speaking of SOAP web service, REST web service or other kind of web services because we are speaking about different things here and people don't understand anymore if we named all of them web services.

Basically SOAP web services are very well established for years and they follow a strict specification that describe how to communicate with them based on the SOAP specification. Now REST web services are a bit newer and basically looks like simpler because they are not using any communication protocol. Basically what you send and receive when you use a REST web service is plain XML. People like it because they can parse the xml the way they want without having to deal with a more sophisticated communication protocol like SOAP.

To me REST services are almost like if you would create a servlet instead of a SOAP web service. The servlet get data in and return data out. The format of the data are xml based. We can also imagine to use something else than xml if we want. For instance tags could be used instead of xml and that would be not REST anymore but something else (Could be even lighter in term of weight because xml is not light by nature). Would we call that still a web service? Yes we could but that will not follow any current standard and this is the main issue here if we start to call everything web services but we can do it the way we want then we are loosing on the interoperability side of the things. That means that the format of the data that is exchanged with the web service is not standardized anymore. That requires then that server and client agree on the format of the data whereas with SOAP this is all predefined already and server and client can interoperate without to know each other because they follow the same standard.

What people don't like with SOAP is that they have hard time to understand it and they cannot generate the queries manually. Computers can do that very well however so this is where we need to be clear: are web services queries and response supposed to be used directly by the end users or do we agree that web services are underneath API called by computer systems based on some normalized standards?

Swift - Remove " character from string

If you want to remove more characters for example "a", "A", "b", "B", "c", "C" from string you can do it this way:

someString = someString.replacingOccurrences(of: "[abc]", with: "", options: [.regularExpression, .caseInsensitive])

How can I add shadow to the widget in flutter?

The given answers do the trick for outer shadow i.e. around the widget. I wanted a shadow on the widget which is inside the boundaries and according to the github issue there is no inset attribute in ShadowBox yet. My workaround was to add a layer of widget with a gradient using the stack widget so that it looks like the widget itself has the shadows. You must use the mediaQuery for dimensions otherwise the layout will be messed up on different devices. Here's a sample of code for better understanding:

            children: <Widget>[
                decoration: BoxDecoration(
                  image: DecorationImage(
                    fit: BoxFit.cover,
                    image: AssetImage("assets/sampleFaces/makeup.jpeg"),
                    // fit: BoxFit.cover,
                height: 350.0,
                decoration: BoxDecoration(
                  gradient: LinearGradient(
                    begin: FractionalOffset.topCenter,
                    end: FractionalOffset.bottomCenter,
                    colors: [
                    stops: [0.95, 5.0],

How do I add a library (android-support-v7-appcompat) in IntelliJ IDEA

As an update to Austyn Mahoney's answer, configuration 'compile' is obsolete and has been replaced with 'implementation' and 'api'.

It will be removed at the end of 2018. For more information see here.

How to pull specific directory with git

In an empty directory:

git init
git remote add [REMOTE_NAME] [GIT_URL]
git fetch REMOTE_NAME
git checkout REMOTE_NAME/BRANCH -- path/to/directory

Converting a Date object to a calendar object

Here's your method:

public static Calendar toCalendar(Date date){ 
  Calendar cal = Calendar.getInstance();
  return cal;

Everything else you are doing is both wrong and unnecessary.

BTW, Java Naming conventions suggest that method names start with a lower case letter, so it should be: dateToCalendar or toCalendar (as shown).

OK, let's milk your code, shall we?

DateFormat formatter = new SimpleDateFormat("yyyyMMdd");
date = (Date)formatter.parse(date.toString()); 

DateFormat is used to convert Strings to Dates (parse()) or Dates to Strings (format()). You are using it to parse the String representation of a Date back to a Date. This can't be right, can it?

The server encountered an internal error that prevented it from fulfilling this request - in servlet 3.0

In here:

    if (ValidationUtils.isNullOrEmpty(lastName)) {
    if (!ValidationUtils.isEmailValid(email)) {

you check for null or empty value on lastname, but in isEmailValid you don't check for empty value. Something like this should do

    if (ValidationUtils.isNullOrEmpty(email) || !ValidationUtils.isEmailValid(email)) {

or better yet, fix your ValidationUtils.isEmailValid() to cope with null email values. It shouldn't crash, it should just return false.

Using ConfigurationManager to load config from an arbitrary location

I provided the configuration values to word hosted .nET Compoent as follows.

A .NET Class Library component being called/hosted in MS Word. To provide configuration values to my component, I created winword.exe.config in C:\Program Files\Microsoft Office\OFFICE11 folder. You should be able to read configurations values like You do in Traditional .NET.

string sMsg = System.Configuration.ConfigurationManager.AppSettings["WSURL"];

Difference between "@id/" and "@+id/" in Android

@id/ and @android:id/ is not the same.

@id/ referencing ID in your application, @android:id/ referencing an item in Android platform.

Eclipse is wrong.

Dynamic WHERE clause in LINQ

It seems much simpler and simpler to use the ternary operator to decide dynamically if a condition is included

List productList = new List();

        productList =
                db.ProductDetail.Where(p => p.ProductDetailID > 0 //Example prop
                && (String.IsNullOrEmpty(iproductGroupName) ? (true):(p.iproductGroupName.Equals(iproductGroupName)) ) //use ternary operator to make the condition dynamic
                && (ID == 0 ? (true) : (p.ID == IDParam))

How to get the value of an input field using ReactJS?

You should use constructor under the class MyComponent extends React.Component

    this.onSubmit = this.onSubmit.bind(this);

Then you will get the result of title

VSCode regex find & replace submatch math?

For beginners, the accepted answer is correct, but a little terse if you're not that familiar with either VSC or Regex.

So, in case this is your first contact with either:

To find and modify text,

  1. In the "Find" step, you can use regex with "capturing groups," e.g. I want to find (group1) and (group2), using parentheses. This would find the same text as I want to find group1 and group2, but with the difference that you can then reference group1 and group2 in the next step:

  2. In the "Replace" step, you can refer to the capturing groups via $1, $2 etc, so you could change the sentence to I found $1 and $2 having a picnic, which would output I found group1 and group2 having a picnic.


  • Instead of just a string, anything inside or outside the () can be a regular expression.

  • $0 refers to the whole match

How to find the port for MS SQL Server 2008?

You could also look with a

netstat -abn

It gives the ports with the corresponding application that keeps them open.

Edit: or TCPView.

Numpy: Divide each row by a vector element

Adding to the answer of stackoverflowuser2010, in the general case you can just use

data = np.array([[1,1,1],[2,2,2],[3,3,3]])

vector = np.array([1,2,3])

data / vector.reshape(-1,1)

This will turn your vector into a column matrix/vector. Allowing you to do the elementwise operations as you wish. At least to me, this is the most intuitive way going about it and since (in most cases) numpy will just use a view of the same internal memory for the reshaping it's efficient too.

android: how to change layout on button click?

I would add an android:onClick to the layout and then change the layout in the activity.

So in the layout

(Other things like source etc.)

Then in the activity add the following:

public void changelayout(View view){

Unique device identification

I have following idea how you can deal with such Access Device ID (ADID):


  • prepare web-page where trusted user e.g. Manager can login from device - that page should show button "Give access to this device"
  • when user press button, page send request to server to generate ADID
  • server gen ADID, store it on whitelist and return to page
  • then page store it in device localstorage
  • trusted user now logout.

Use device

  • Then other user e.g. Employee using same device go to and page send to server request for statistics including parameter ADID (previous stored in localstorage)
  • server checks if the ADID is on the whitelist, and if yes then return data

In this approach, as long user use same browser and don't make device reset, the device has access to data. If someone made device-reset then again trusted user need to login and gen ADID.

You can even create some ADID management system for trusted user where on generate ADID he can also input device serial-number and in future in case of device reset he can find this device and regenerate ADID for it (which not increase whitelist size) and he can also drop some ADID from whitelist for devices which he will not longer give access to server data.

In case when sytem use many domains/subdomains te manager after login should see many "Give access from domain to this device" buttons - each button will redirect device do proper domain, gent ADID and redirect back.


Simpler approach based on links:

  • Manager login to system using any device and generate ONE-TIME USE LINK (which works e.g. 24h).
  • Then manager send this link to employee (or someone else; e.g. by email) which put that link into device and server returns ADID to device which store it in Local Storage. After that link above stops working - so only the system and device know ADID
  • Then employee using this device can read data from because it has ADID which is on servers whitelist

Convert String array to ArrayList

in most cases the List<String> should be enough. No need to create an ArrayList

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;


String[] words={"ace","boom","crew","dog","eon"};
List<String> l = Arrays.<String>asList(words);

// if List<String> isnt specific enough:
ArrayList<String> al = new ArrayList<String>(l);

How can I symlink a file in Linux?

I find a bit confusing the terminologies "target" and "directory" in the man information.

The target is the folder that we are symlinking to and the directory the actual symlink (not the directory that you will be symlinking to), if anyone is experiencing the same confusion, don't feel alone.

This is my interpretation of creating a Symlink (in linux):


You can navigate to the folder where you want to create the symlink and run the command or specify the FULL PATH for your symlink instead of NAME-OF-YOUR-SYMLINK.




I hope this helps to those (still) slighly confused.

How to get the CPU Usage in C#?

After spending some time reading over a couple different threads that seemed pretty complicated I came up with this. I needed it for an 8 core machine where I wanted to monitor SQL server. For the code below then I passed in "sqlservr" as appName.

private static void RunTest(string appName)
    bool done = false;
    PerformanceCounter total_cpu = new PerformanceCounter("Process", "% Processor Time", "_Total");
    PerformanceCounter process_cpu = new PerformanceCounter("Process", "% Processor Time", appName);
    while (!done)
        float t = total_cpu.NextValue();
        float p = process_cpu.NextValue();
        Console.WriteLine(String.Format("_Total = {0}  App = {1} {2}%\n", t, p, p / t * 100));

It seems to correctly measure the % of CPU being used by SQL on my 8 core server.

Proper use cases for Android UserManager.isUserAGoat()?

Complementing the @djechlin answer (good answer by the way!), this function call could be also used as dummy code to hold a breakpoint in an IDE when you want to stop in some specific iteration or a particular recursive call, for example:

enter image description here

isUserAGoat() could be used instead of a dummy variable declaration that will be shown in the IDE as a warning and, in Eclipse particular case, will clog the breakpoint mark, making it difficult to enable/disable it. If the method is used as a convention, all the invocations could be later filtered by some script (during commit phase maybe?).

enter image description here

Google guys are heavy Eclipse users (they provide several of their projects as Eclipse plugins: Android SDK, GAE, etc), so the @djechlin answer and this complementary answer make a lot of sense (at least for me).

How to edit the legend entry of a chart in Excel?

The data series names are defined by the column headers. Add the names to the column headers that you would like to use as titles for each of your data series, select all of the data (including the headers), then re-generate your graph. The names in the headers should then appear as the names in the legend for each series.

Column headers become data series titles in graph legend

UnicodeEncodeError: 'charmap' codec can't encode - character maps to <undefined>, print function

I dug deeper into this and found the best solutions are here.

In my case I solved "UnicodeEncodeError: 'charmap' codec can't encode character "

original code:

print("Process lines, file_name command_line %s\n"% command_line))

New code:

print("Process lines, file_name command_line %s\n"% command_line.encode('utf-8'))  

NameError: global name 'xrange' is not defined in Python 3

You are trying to run a Python 2 codebase with Python 3. xrange() was renamed to range() in Python 3.

Run the game with Python 2 instead. Don't try to port it unless you know what you are doing, most likely there will be more problems beyond xrange() vs. range().

For the record, what you are seeing is not a syntax error but a runtime exception instead.

If you do know what your are doing and are actively making a Python 2 codebase compatible with Python 3, you can bridge the code by adding the global name to your module as an alias for range. (Take into account that you may have to update any existing range() use in the Python 2 codebase with list(range(...)) to ensure you still get a list object in Python 3):

    # Python 2
except NameError:
    # Python 3, xrange is now named range
    xrange = range

# Python 2 code that uses xrange(...) unchanged, and any
# range(...) replaced with list(range(...))

or replace all uses of xrange(...) with range(...) in the codebase and then use a different shim to make the Python 3 syntax compatible with Python 2:

    # Python 2 forward compatibility
    range = xrange
except NameError:

# Python 2 code transformed from range(...) -> list(range(...)) and
# xrange(...) -> range(...).

The latter is preferable for codebases that want to aim to be Python 3 compatible only in the long run, it is easier to then just use Python 3 syntax whenever possible.

How to get the width and height of an android.widget.ImageView?

Post to the UI thread works for me.

final ImageView iv = (ImageView)findViewById(; Runnable() {
            public void run() {
                int width = iv.getMeasuredWidth();
                int height = iv.getMeasuredHeight();


Using npm behind corporate proxy .pac

You can check Fiddler if NPM is giving Authentication error. It is easy to install and configure. Set Fiddler Rule to Automatically Authenticated.In .npmrc set these properties


It worked for me :)

How to set background color of an Activity to white programmatically?

The best method right now is of course

getWindow().getDecorView().setBackgroundColor(ContextCompat.getColor(MainActivity.this, R.color.main_activity_background_color));

Please be aware though, if you have anything set as the background color in Designer, it will overwrite anything you try to set in your code.

Hide Command Window of .BAT file that Executes Another .EXE File

To make the command window of a .bat file that executes a .exe file exit out as fast as possible, use the line @start before the file you're trying to execute. Here is an example:

(insert other code here)
@start executable.exe
(insert other code here)

You don't have to use other code with @start executable.exe.

Codeigniter - multiple database connections

If you need to connect to more than one database simultaneously you can do so as follows:

$DB1 = $this->load->database('group_one', TRUE);
$DB2 = $this->load->database('group_two', TRUE);

Note: Change the words “group_one” and “group_two” to the specific group names you are connecting to (or you can pass the connection values as indicated above).

By setting the second parameter to TRUE (boolean) the function will return the database object.

Visit for further information.

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;

Apply function to each column in a data frame observing each columns existing data type

If you want to learn your data summary (df) provides the min, 1st quantile, median and mean, 3rd quantile and max of numerical columns and the frequency of the top levels of the factor columns.

JavaFX Location is not set error message

I've stumbled upon the same problem. Program was running great from Eclipse via "Run" button, but NOT from runnable JAR which I'd exported before. My solution was:

1) Move Main class to default package

2) Set other path for Eclipse, and other while running from the JAR file (paste this into

public static final String sourcePath = isProgramRunnedFromJar() ? "src/" : "";
public static boolean isProgramRunnedFromJar() {
    File x = getCurrentJarFileLocation();
        return false;
    } else {
        return true;
public static File getCurrentJarFileLocation() {
        try {
            return new File(Main.class.getProtectionDomain().getCodeSource().getLocation().toURI().getPath());
        } catch(URISyntaxException e){
            return null;

And after that in start method you have to load files like this:

FXMLLoader loader = new FXMLLoader(getClass().getResource(sourcePath +"MainScene.fxml"));

It works for me in Eclipse Mars with e(fx)clipse plugin.

IE prompts to open or save json result from server

Even though it's not supposedly the correct way, setting the content type to text/html made IE deal with this correctly for me:

return Json(result, "text/html");

Works in all the version that F12 tools gives you in IE9.

Jquery button click() function is not working

The click event is not bound to your new element, use a jQuery.on to handle the click.

keypress, ctrl+c (or some combo like that)

As of 2019, this works (in Chrome at least)

$(document).keypress(function(e) {
    var key = (event.which || event.keyCode) ;
  if(e.ctrlKey) {
        if (key == 26) { console.log('Ctrl+Z was pressed') ; }
        else if (key == 25) { console.log('Ctrl+Y was pressed') ; }
        else if (key == 19) { console.log('Ctrl+S was pressed') ; }
    else { console.log('Ctrl', key, 'was pressed') ; }

MultipartException: Current request is not a multipart request

When you are using Postman for multipart request then don't specify a custom Content-Type in Header. So your Header tab in Postman should be empty. Postman will determine form-data boundary. In Body tab of Postman you should select form-data and select file type. You can find related discussion at

How can I convert radians to degrees with Python?

Python includes two functions in the math package; radians converts degrees to radians, and degrees converts radians to degrees.

To match the output of your calculator you need:

>>> math.cos(math.radians(1))

Note that all of the trig functions convert between an angle and the ratio of two sides of a triangle. cos, sin, and tan take an angle in radians as input and return the ratio; acos, asin, and atan take a ratio as input and return an angle in radians. You only convert the angles, never the ratios.

Add numpy array as column to Pandas data frame

Consider using a higher dimensional datastructure (a Panel), rather than storing an array in your column:

In [11]: p = pd.Panel({'df': df, 'csc': csc})

In [12]: p.df
   0  1  2
0  1  2  3
1  4  5  6
2  7  8  9

In [13]:
   0  1  2
0  0  1  0
1  0  0  1
2  1  0  0

Look at cross-sections etc, etc, etc.

In [14]: p.xs(0)
   csc  df
0    0   1
1    1   2
2    0   3

See the docs for more on Panels.

JUnit tests pass in Eclipse but fail in Maven Surefire

I had the same problem, and the solution for me was to allow Maven to handle all dependencies, including to local jars. I used Maven for online dependencies, and configured build path manually for local dependencies. Thus, Maven was not aware of the dependencies I configured manually.

I used this solution to install the local jar dependencies into Maven:

How to add local jar files in maven project?

How to make matrices in Python?

you can also use append function

b = [ ]

for x in range(0, 5):
    b.append(["O"] * 5)

def print_b(b):
    for row in b:
        print " ".join(row)

Adb Devices can't find my phone

I have a Fascinate as well, and had to change the phone's USB communication mode from MODEM to PDA. Use:

  • enter **USBUI (**87284)

to change both USB and UART to PDA mode. I also had to disconnect and reconnect the USB cable. Once Windows re-recognized the device again, "adb devices" started returning my device.

BTW if you use CDMA workshop or the equivalent, you will need to switch the setting back to MODEM.

How to get Chrome to allow mixed content?

You could use cors anywhere for testing purposes. But its note recommend for production environments.

something like:

Java: Get month Integer from Date

java.util.Date date= new Date();
Calendar cal = Calendar.getInstance();
int month = cal.get(Calendar.MONTH);

take(1) vs first()

There's one really important difference which is not mentioned anywhere.

take(1) emits 1, completes, unsubscribes

first() emits 1, completes, but doesn't unsubscribe.

It means that your upstream observable will still be hot after first() which is probably not expected behavior.

UPD: This referes to RxJS 5.2.0. This issue might be already fixed.

Are 64 bit programs bigger and faster than 32 bit versions?

Only justification for moving your application to 64 bit is need for more memory in applications like large databases or ERP applications with at least 100s of concurrent users where 2 GB limit will be exceeded fairly quickly when applications cache for better performance. This is case specially on Windows OS where integer and long is still 32 bit (they have new variable _int64. Only pointers are 64 bit. In fact WOW64 is highly optimised on Windows x64 so that 32 bit applications run with low penalty on 64 bit Windows OS. My experience on Windows x64 is 32 bit application version run 10-15% faster than 64 bit since in former case at least for proprietary memory databases you can use pointer arithmatic for maintaining b-tree (most processor intensive part of database systems). Compuatation intensive applications which require large decimals for highest accuracy not afforded by double on 32-64 bit operating system. These applications can use _int64 in natively instead of software emulation. Of course large disk based databases will also show improvement over 32 bit simply due to ability to use large memory for caching query plans and so on.

multiple axis in matplotlib with different scales

if you want to do very quick plots with secondary Y-Axis then there is much easier way using Pandas wrapper function and just 2 lines of code. Just plot your first column then plot the second but with parameter secondary_y=True, like this:

df.A.plot(label="Points", legend=True)
df.B.plot(secondary_y=True, label="Comments", legend=True)

This would look something like below:

enter image description here

You can do few more things as well. Take a look at Pandas plotting doc.

Error - Android resource linking failed (AAPT2 27.0.3 Daemon #0)

I was facing same issue and it is resolved by removing error from resource files like style, colors files in values folder. In my case, error in style colors as below:

 <style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar">
    <item name="android:textColorPrimary">**@color/colorPrimary**</item>
    <item name="android:textColorSecondary">**@color/colorPrimaryDark**</item>

what is trailing whitespace and how can I handle this?

Trailing whitespace is any spaces or tabs after the last non-whitespace character on the line until the newline.

In your posted question, there is one extra space after try:, and there are 12 extra spaces after pass:

>>> post_text = '''\
...             if self.tagname and self.tagname2 in list1:
...                 try: 
...                     question = soup.find("div", "post-text")
...                     title = soup.find("a", "question-hyperlink")
...                     self.list2.append(str(title)+str(question)+url)
...                     current += 1
...                 except AttributeError:
...                     pass            
...   "%s questions passed, %s questions \
...                 collected" % (count, current))
...             count += 1
...         return self.list2
... '''
>>> for line in post_text.splitlines():
...     if line.rstrip() != line:
...         print(repr(line))
'                try: '
'                    pass            '

See where the strings end? There are spaces before the lines (indentation), but also spaces after.

Use your editor to find the end of the line and backspace. Many modern text editors can also automatically remove trailing whitespace from the end of the line, for example every time you save a file.

Convert String to Type in C#


Type type = Type.GetType(inputString); //target type
object o = Activator.CreateInstance(type); // an instance of target type
YourType your = (YourType)o;

Jon Skeet is right as usually :)

Update: You can specify assembly containing target type in various ways, as Jon mentioned, or:

YourType your = (YourType)Activator.CreateInstance("AssemblyName", "NameSpace.MyClass");

How to prettyprint a JSON file?

To be able to pretty print from the command line and be able to have control over the indentation etc. you can set up an alias similar to this:

alias jsonpp="python -c 'import sys, json; print json.dumps(json.load(sys.stdin), sort_keys=True, indent=2)'"

And then use the alias in one of these ways:

cat myfile.json | jsonpp
jsonpp < myfile.json

"implements Runnable" vs "extends Thread" in Java

With the release of Java 8, there is now a third option.

Runnable is a functional interface, which means that instances of it can be created with lambda expressions or method references.

Your example can be replaced with:

new Thread(() -> { /* Code here */ }).start()

or if you want to use an ExecutorService and a method reference:


These are not only much shorter than your examples, but also come with many of the advantages stated in other answers of using Runnable over Thread, such as single responsibility and using composition because you're not specializing the thread's behaviour. This way also avoids creating an extra class if all you need is a Runnable as you do in your examples.

Calculate percentage saved between two numbers?

100% - discounted price / full price

how to read xml file from url using php

It is working for me. I think you probably need to use urlencode() on each of the components of $map_url.

Best way to compare dates in Android

Note that the right format is ("dd/MM/yyyy") before the code works. "mm" means minuts !

String valid_until = "01/07/2013";
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
Date strDate = null;
try {
    strDate = sdf.parse(valid_until);
} catch (ParseException e) {
if (new Date().after(strDate)) {
    catalog_outdated = 1;

How to disable CSS in Browser for testing purposes

Install Adblock Plus, then add *.css rule in Filters options (custom filters tab). The method affect only on external stylesheets. It doesn't turn off inline styles.

Disable all external CSS

This method does exactly what you asked.

How to make the corners of a button round?

Create rounded_btn.xml file in Drawable folder...

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android=""> 
     <solid android:color="@color/#FFFFFF"/>    

     <stroke android:width="1dp"

     <padding android:left="1dp"

     <corners android:bottomRightRadius="5dip" android:bottomLeftRadius="5dip" 
         android:topLeftRadius="5dip" android:topRightRadius="5dip"/> 

and use this.xml file as a button background

android:text="Test" />

Android changing Floating Action Button color

I got the same problem and its all snatching my hair. Thanks for this

What we can do..

 favourite_fab.setImageDrawable(ContextCompat.getDrawable(getBaseContext(), R.drawable.favourite_selected));

it works fine for me and wish for others who'll reach here.

How to perform Unwind segue programmatically?

Backwards compatible solution that will work for versions prior to ios6, for those interested:

- (void)unwindToViewControllerOfClass:(Class)vcClass animated:(BOOL)animated {

    for (int i=self.navigationController.viewControllers.count - 1; i >= 0; i--) {
        UIViewController *vc = [self.navigationController.viewControllers objectAtIndex:i];
        if ([vc isKindOfClass:vcClass]) {
            [self.navigationController popToViewController:vc animated:animated];

How do I get a string format of the current date time, in python?


import datetime
    '1: test-{date:%Y-%m-%d_%H:%M:%S}.txt'.format( )

d =
print( "2a: {:%B %d, %Y}".format(d))

# see the f" to tell python this is a f string, no .format
print(f"2b: {d:%B %d, %Y}")

print(f"3: Today is {} yay")

1: test-2018-02-14_16:40:52.txt

2a: March 04, 2018

2b: March 04, 2018

3: Today is 2018-11-11 yay


Using the new string format to inject value into a string at placeholder {}, value is the current time.

Then rather than just displaying the raw value as {}, use formatting to obtain the correct date format.

OperationalError, no such column. Django

I had same issue with sqlite. My looked all right. I did the following:

sqlite3 db.sqlite3
PRAGMA table_info(table_name);

Thru PRAGMA I was able to see that there was columns missing in the table failing. I dropped all tables in the app. Be careful because this will make lose your data in the tables.

DROP table table_name

Then do this:

python makemigrations your_app
python migrate your_app
python sqlmigrate your_app 0001

Then enter again to sqlite as follows and paste all the code you got from sqlimigrate:

sqlite3 db.sqlite3

As an example, this is what I pasted inside sqlite:

CREATE TABLE "adpet_ad" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "title" varchar(200) NOT NULL, "breed" varchar(30) NULL, "weight" decimal NULL, "age" integer NULL, "text" text NOT NULL, "created_at" datetime NOT NULL, "updated_at" datetime NOT NULL, "picture" BLOB NULL, "content_type" varchar(256) NULL, "name" varchar(100) NULL, "phone" varchar(31) NOT NULL, "gender_id" integer NULL REFERENCES "adpet_gender" ("id") DEFERRABLE INITIALLY DEFERRED, "owner_id" integer NOT NULL REFERENCES "auth_user" ("id") DEFERRABLE INITIALLY DEFERRED, "size_id" integer NULL REFERENCES "adpet_size" ("id") DEFERRABLE INITIALLY DEFERRED, "specie_id" integer NULL REFERENCES "adpet_specie" ("id") DEFERRABLE INITIALLY DEFERRED, "sterilized_id" integer NULL REFERENCES "adpet_sterilized" ("id") DEFERRABLE INITIALLY DEFERRED, "vaccinated_id" integer NULL REFERENCES "adpet_vaccinated" ("id") DEFERRABLE INITIALLY DEFERRED); Repeater get current index, pointer, or counter

Add a label control to your Repeater's ItemTemplate. Handle OnItemCreated event.


<asp:Repeater ID="rptr" runat="server" OnItemCreated="RepeaterItemCreated">
        <div id="width:50%;height:30px;background:#0f0a0f;">
            <asp:Label ID="lblSr" runat="server" 
               style="width:30%;float:left;text-align:right;text-indent:-2px;" />
               style="width:65%;float:right;text-align:left;text-indent:-2px;" >
            <%# Eval("Item") %>

Code Behind:

    protected void RepeaterItemCreated(object sender, RepeaterItemEventArgs e)
        Label l = e.Item.FindControl("lblSr") as Label;
        if (l != null)
            l.Text = e.Item.ItemIndex + 1+"";

How can I get all sequences in an Oracle database?

select sequence_owner, sequence_name from dba_sequences;

DBA_SEQUENCES -- all sequences that exist 
ALL_SEQUENCES  -- all sequences that you have permission to see 
USER_SEQUENCES  -- all sequences that you own

Note that since you are, by definition, the owner of all the sequences returned from USER_SEQUENCES, there is no SEQUENCE_OWNER column in USER_SEQUENCES.

What is difference between mutable and immutable String in java

What is difference between mutable and immutable String in java

immutable exist, mutable don't.

How do I check whether a file exists without exceptions?

TL;DR To quickly check the existence of a file or a folder, use the Path module. Here is a single line code (after import)!

from pathlib import Path
if Path("myfile.txt").exists(): # works for both file and folders
    # do stuffs...

The pathlib module was introduced in Python 3.4, so you need to have Python 3.4+, this lib makes your life much easier and it is pretty to use, here is more doc about it (

BTW, if you are going to reuse the path, then it is better to assign it to a variable

so will become

from pathlib import Path
p = Path("loc/of/myfile.txt")
if p.exists(): # works for both file and folders
    # do stuffs...

Is it possible to use jQuery to read meta tags

Just use something like:

var author = $('meta[name=author]').attr('content');

What is in your .vimrc?

My .vimrc includes (among other, more usefull things) the following line:

set statusline=%2*%n\|%<%*%-.40F%2*\|\ %2*%M\ %3*%=%1*\ %1*%2.6l%2*x%1*%1.9(%c%V%)%2*[%1*%P%2*]%1*%2B

I got bored while learning for my high school finals.

How to make war file in Eclipse

File -> Export -> Web -> WAR file

OR in Kepler follow as shown below :

enter image description here

What is the !! (not not) operator in JavaScript?

It's not a single operator, it's two. It's equivalent to the following and is a quick way to cast a value to boolean.

val.enabled = !(!enable);

Solve Cross Origin Resource Sharing with Flask

I used decorator given by Armin Ronacher with little modifications (due to different headers that are requested by the client).And that worked for me. (where I use angular as the requester requesting application/json type).

The code is slightly modified at below places,

from flask import jsonify

@app.route('/my_service', methods=['POST', 'GET','OPTIONS'])
def my_service():
    return jsonify(foo='cross domain ftw')

jsonify will send a application/json type, else it will be text/html. headers are added as the client in my case request for those headers

 const httpOptions = {
      headers: new HttpHeaders({
        'Content-Type': 'application/json',
    return<any>(url, item,httpOptions)

How can I convert a Word document to PDF?

Spire.Doc for Java, it is a professional Java API that enables Java applications to create, convert, manipulate and print Word documents without using Microsoft Office.You can easily convert Word to PDF with several lines of codes as follows.

import com.spire.doc.Document;
import com.spire.doc.FileFormat;
import com.spire.doc.ToPdfParameterList;

public class WordToPDF {
public static void main(String[] args)  {

    //Create Document object
    Document doc = new Document();

    //Load the file from disk.

    //create an instance of ToPdfParameterList.
    ToPdfParameterList ppl=new ToPdfParameterList();

    //embeds full fonts by default when IsEmbeddedAllFonts is set to true.

    //set setDisableLink to true to remove the hyperlink effect for the result PDF page.
    //set setDisableLink to false to preserve the hyperlink effect for the result PDF page.

    //Set the output image quality as 40% of the original image. 80% is the default setting.

    //Save to file.

After running the code snippets above, all formats of the original Word document can be copied into PDF perfectly.

How to access the correct `this` inside a callback?

this in JS:

The value of this in JS is 100% determined by how a function is called, and not how it is defined. We can relatively easily find the value of this by the 'left of the dot rule':

  1. When the function is created using the function keyword the value of this is the object left of the dot of the function which is called
  2. If there is no object left of the dot then the value of this inside a function is often the global object (global in node, window in browser). I wouldn't recommend using the this keyword here because it is less explicit than using something like window!
  3. There exist certain constructs like arrow functions and functions created using the Function.prototype.bind() a function that can fix the value of this. These are exceptions of the rule but are really helpful to fix the value of this.

Example in nodeJS = 'module data';
// This outside a function in node refers to module.exports object

const obj1 = {
    data: "obj1 data",
    met1: function () {
    met2: () => {

const obj2 = {
    data: "obj2 data",
    test1: function () {
    test2: function () {
    test3: obj1.met1,
    test4: obj1.met2,



enter image description here

Let me walk you through the outputs 1 by 1 (ignoring the first log starting from the second):

  1. this is obj2 because of the left of the dot rule, we can see how test1 is called obj2.test1();. obj2 is left of the dot and thus the this value.
  2. Even though obj2 is left of the dot, test2 is bound to obj1 via the bind() method. So the this value is obj1.
  3. obj2 is left of the dot from the function which is called: obj2.test3(). Therefore obj2 will be the value of this.
  4. In this case: obj2.test4() obj2 is left of the dot. However, arrow functions don't have their own this binding. Therefore it will bind to the this value of the outer scope which is the module.exports an object which was logged in the beginning.
  5. We can also specify the value of this by using the call function. Here we can pass in the desired this value as an argument, which is obj2 in this case.

Lost httpd.conf file located apache

Get the path of running Apache

$ ps -ef | grep apache
apache   12846 14590  0 Oct20 ?        00:00:00 /usr/sbin/apache2

Append -V argument to the path

$ /usr/sbin/apache2 -V | grep SERVER_CONFIG_FILE
-D SERVER_CONFIG_FILE="/etc/apache2/apache2.conf"


EF 5 Enable-Migrations : No context type was found in the assembly

Adding a class which inherits DbContext resolved my problem:

public class MyDbContext : DbContext { public MyDbContext() { } }

What does <a href="#" class="view"> mean?

Don't forget to look at the Javascript as well. My guess is that there is custom Javascript code getting executed when you click on the link and it's that Javascript that is generating the URL and navigating to it.

Maintaining Session through Angular.js

Here is a kind of snippet for you:

app.factory('Session', function($http) {
  var Session = {
    data: {},
    saveSession: function() { /* save session data to db */ },
    updateSession: function() { 
      /* load data from db */
      $http.get('session.json').then(function(r) { return =;});
  return Session; 

Here is Plunker example how you can use that:

How to find the socket buffer size of linux

Atomic size is 4096 bytes, max size is 65536 bytes. Sendfile uses 16 pipes each of 4096 bytes size. cmd : ioctl(fd, FIONREAD, &buff_size).

What event handler to use for ComboBox Item Selected (Selected Item not necessarily changed)

private void OnDropDownClosed(object sender, EventArgs e)
     if (combobox.SelectedItem == null) return;
     // Do actions

Correct way to push into state array


if u also want ur UI (ie. ur flatList) to be up to date, use PrevState: in the example below if user clicks on the button , it is going to add a new object to the list( both in the model and UI)

data: ['shopping','reading'] // declared in constructor
onPress={() => {this.setState((prevState, props) => {
return {data: [new obj].concat( };

How to get base url with jquery or javascript?

You can easily get it with:

var currentUrl = window.location.href;

or, if you want the original URL, use:

var originalUrl = window.location.origin;

How to show what a commit did?

The answers by Bomber and Jakub (Thanks!) are correct and work for me in different situations.

For a quick glance at what was in the commit, I use

git show <replace this with your commit-id>

But I like to view a graphical Diff when studying something in detail and have set up a P4diff as my git diff and then use

git diff <replace this with your commit-id>^!

mysql update multiple columns with same now()

Mysql isn't very clever. When you want to use the same timestamp in multiple update or insert queries, you need to declare a variable.

When you use the now() function, the system will call the current timestamp every time you call it in another query.

What is the difference between CMD and ENTRYPOINT in a Dockerfile?

• A Dockerfile should specify at least one CMD or ENTRYPOINT instruction

• Only the last CMD and ENTRYPOINT in a Dockerfile will be used

• ENTRYPOINT should be defined when using the container as an executable

• You should use the CMD instruction as a way of defining default arguments for the command defined as ENTRYPOINT or for executing an ad-hoc command in a container

• CMD will be overridden when running the container with alternative arguments

• ENTRYPOINT sets the concrete default application that is used every time a container is created using the image

• If you couple ENTRYPOINT with CMD, you can remove an executable from CMD and just leave its arguments which will be passed to ENTRYPOINT

• The best use for ENTRYPOINT is to set the image's main command, allowing that image to be run as though it was that command (and then use CMD as the default flags)

How to import Swagger APIs into Postman?

  • Click on the orange button ("choose files")
  • Browse to the Swagger doc (swagger.yaml)
  • After selecting the file, a new collection gets created in POSTMAN. It will contain folders based on your endpoints.

You can also get some sample swagger files online to verify this(if you have errors in your swagger doc).

Rails: Why "sudo" command is not recognized?

Sudo is a Unix specific command designed to allow a user to carry out administrative tasks with the appropriate permissions. Windows doesn't not have (need?) this.

Yes, windows don't have sudo on its terminal. Try using pip instead.

  1. Install pip using the steps here.
  2. type pip install [package name] on the terminal. In this case, it may be pdfkit or wkhtmltopdf.

Search text in fields in every table of a MySQL database

Although this question is old , here is how you can do it if you are using mysql workbench 6.3. ( Most likely it also works for other versions)

Right click your schema and "Search table data" , enter your value and hit "Start Search". Thats it.

File Upload ASP.NET MVC 3.0

Giving complete Solution

First use input in .CShtml in MVC View

<input type="file" id="UploadImg" /></br>
<img id="imgPreview" height="200" width="200" />

Now call Ajax call

  $("#UploadImg").change(function () {
    var data = new FormData();
    var files = $("#UploadImg").get(0).files;
    if (files.length > 0) {
        data.append("MyImages", files[0]);

        // url: "Controller/ActionMethod"
        url: "/SignUp/UploadFile",
        type: "POST",
        processData: false,
        contentType: false,
        data: data,
        success: function (response)
            //code after success
            $("#imgPreview").attr('src', '/Upload/' + response);
        error: function (er) {


Controller Json Call

public JsonResult UploadFile()
        string _imgname = string.Empty;
        if (System.Web.HttpContext.Current.Request.Files.AllKeys.Any())
            var pic = System.Web.HttpContext.Current.Request.Files["MyImages"];
            if (pic.ContentLength > 0)
                var fileName = Path.GetFileName(pic.FileName);
                var _ext = Path.GetExtension(pic.FileName);

                _imgname = Guid.NewGuid().ToString();
                var _comPath = Server.MapPath("/MyFolder") + _imgname + _ext;
                _imgname = "img_" + _imgname + _ext;

                ViewBag.Msg = _comPath;
                var path = _comPath;
                tblAssignment assign = new tblAssignment();
                assign.Uploaded_Path = "/MyFolder" + _imgname + _ext;
                // Saving Image in Original Mode
        return Json(Convert.ToString(_imgname), JsonRequestBehavior.AllowGet);

How do I get the total Json record count using JQuery?

Why would you want length in this case?

If you do want to check for length, have the server return a JSON array with key-value pairs like this:


In JSON, [ and ] represents an array (with a length property), { and } represents a object (without a length property). You can iterate through the members of a object, but you will get functions as well, making a length check of the numbers of members useless except for iterating over them.

How to concatenate strings in a Windows batch file?

What about:

@echo off
set myvar="the list: "
for /r %%i in (*.doc) DO call :concat %%i
echo %myvar%
goto :eof

set myvar=%myvar% %1;
goto :eof

Cross-browser custom styling for file upload button

It's also easy to style the label if you are working with Bootstrap and LESS:

label {

    > input[type="file"] {
        display: none;

Git will not init/sync/update new submodules

I had a similar problem with a submodule. It just didn't want to be cloned/pulled/updated/whatever.

When trying to re-add the submodule using git submodule add [email protected] destination I got the following output:

A git directory for 'destination' is found locally with remote(s):
  origin        [email protected]
If you want to reuse this local git directory instead of cloning again from
  [email protected]
use the '--force' option. If the local git directory is not the correct repo
or you are unsure what this means choose another name with the '--name' option.

So, I tried to enforce the add command:
git submodule add --force [email protected] destination

That worked in my case.

#1062 - Duplicate entry for key 'PRIMARY'

The DB I was importing had a conflict during the import due to the presence of a column both autoincrement and primary key.

The problem was that in the .sql file the table was chopped into multiple "INSERT INTO" and during the import these queries were executed all together.

MY SOLUTION was to deselect the "Run multiple queries in each execution" on Navicat and it worked perfectly

Rails: Adding an index after adding column

For those who are using postgresql db and facing error

StandardError: An error has occurred, this and all later migrations canceled:

=== Dangerous operation detected #strong_migrations ===

Adding an index non-concurrently blocks writes

please refer this article


class AddAncestryToWasteCodes < ActiveRecord::Migration[6.0]

  def change
    add_column :waste_codes, :ancestry, :string
    add_index :waste_codes, :ancestry, algorithm: :concurrently

Bootstrap 3 Horizontal and Vertical Divider

I know this is an "older" post. This question and the provided answers helped me get ideas for my own problem. I think this solution addresses the OP question (intersecting borders with 4 and 2 columns depending on display)


css based on OP information, media query at end is for med & lg view.

.vr-all {
    border-right:1px solid #CC0000;
.vr-xs {
.vr-md {
.hrspacing { padding:0px; }
.hrcolor {
    border-color: #CC0000;
    border-style: solid;
    border-bottom: 1px;
/* for medium and up */
    .vr-xs {
        border-right:1px solid #CC0000;

html adjustments to OP provided code. Red border and Img links for example.

<div class="container">
  <div class="row">
        <div class="col-xs-6 col-sm-6 col-md-3 text-center vr-all" id="one">
            <h5>Rich Media Ad Production</h5>
            <img src="" />
        <div class="col-xs-6 col-sm-6 col-md-3 text-center vr-xs" id="two">
            <h5>Web Design & Development</h5>
            <img src="" >

        <!-- hr for only x-small/small viewports -->
        <div class="col-xs-12 col-sm-12 hidden-md hidden-lg hrspacing"><hr class="hrcolor"></div>

        <div class="col-xs-6 col-sm-6 col-md-3 text-center vr-all" id="three">
            <h5>Mobile Apps Development</h5>
            <img src="" >
        <div class="col-xs-6 col-sm-6 col-md-3 text-center vr-md" id="four">
            <h5>Creative Design</h5>
            <img src="" >

        <!-- hr for for all viewports -->
        <div class="col-xs-12 hrspacing"><hr class="hrcolor"></div>

        <div class="col-xs-6 col-sm-6 col-md-3 text-center vr-all" id="five">
            <h5>Web Analytics</h5>
            <img src="" >
        <div class="col-xs-6 col-sm-6 col-md-3 text-center vr-xs" id="six">
            <h5>Search Engine Marketing</h5>
            <img src="" >

        <!-- hr for only x-small/small viewports -->
        <div class="col-xs-12 col-sm-12 hidden-md hidden-lg hrspacing"><hr class="hrcolor"></div>

        <div class="col-xs-6 col-sm-6 col-md-3 text-center vr-all" id="seven">
            <h5>Mobile Apps Development</h5>
            <img src="" >
        <div class="col-xs-6 col-sm-6 col-md-3 text-center vr-md" id="eight">
            <h5>Quality Assurance</h5>
            <img src="" >


How do I add a linker or compile flag in a CMake file?

Suppose you want to add those flags (better to declare them in a constant):

SET(GCC_COVERAGE_COMPILE_FLAGS "-fprofile-arcs -ftest-coverage")

There are several ways to add them:

  1. The easiest one (not clean, but easy and convenient, and works only for compile flags, C & C++ at once):

  2. Appending to corresponding CMake variables:

  3. Using target properties, cf. doc CMake compile flag target property and need to know the target name.

    get_target_property(TEMP ${THE_TARGET} COMPILE_FLAGS)
      SET(TEMP "") # Set to empty string
      SET(TEMP "${TEMP} ") # A space to cleanly separate from existing content
    # Append our values
    set_target_properties(${THE_TARGET} PROPERTIES COMPILE_FLAGS ${TEMP} )

Right now I use method 2.

Converting serial port data to TCP/IP in a Linux environment

I think your question isn't quite clear. There are several answers here on how to catch the data coming into a Linux's serial port, but perhaps your problem is the other way around?

If you need to catch the data coming out of a Linux's serial port and send it to a server, there are several little hardware gizmos that can do this, starting with the simple serial print server such as this Lantronix gizmo.

No, I'm not affiliated with Lantronix in any way.

What is "android:allowBackup"?

This is not explicitly mentioned, but based on the following docs, I think it is implied that an app needs to declare and implement a BackupAgent in order for data backup to work, even in the case when allowBackup is set to true (which is the default value).

How to convert Calendar to java.sql.Date in Java?

Use stmt.setDate(1, new java.sql.Date(cal.getTimeInMillis()))

How can I send cookies using PHP curl in addition to CURLOPT_COOKIEFILE?

If the cookie is generated from script, then you can send the cookie manually along with the cookie from the file(using cookie-file option). For example:

# sending manually set cookie
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Cookie: test=cookie"));

# sending cookies from file
curl_setopt($ch, CURLOPT_COOKIEFILE, $ckfile);

In this case curl will send your defined cookie along with the cookies from the file.

If the cookie is generated through javascrript, then you have to trace it out how its generated and then you can send it using the above method(through http-header).

The utma utmc, utmz are seen when cookies are sent from Mozilla. You shouldn't bet worry about these things anymore.

Finally, the way you are doing is alright. Just make sure you are using absolute path for the file names(i.e. /var/dir/cookie.txt) instead of relative one.

Always enable the verbose mode when working with curl. It will help you a lot on tracing the requests. Also it will save lot of your times.

curl_setopt($ch, CURLOPT_VERBOSE, true);

Drop a temporary table if it exists

From SQL Server 2016 you can just use


On previous versions you can use

/*Then it exists*/
   client_id INT

You could also consider truncating the table instead rather than dropping and recreating.

     client_id INT

Hibernate Query By Example and Projections

I do not really think so, what I can find is the word "this." causes the hibernate not to include any restrictions in its query, which means it got all the records lists. About the hibernate bug that was reported, I can see it's reported as fixed but I totally failed to download the Patch.

Position absolute and overflow hidden

What about position: relative for the outer div? In the example that hides the inner one. It also won't move it in its layout since you don't specify a top or left.

Jackson: how to prevent field serialization

set variable as


This allows variable to get skipped by json serializer

What does the SQL Server Error "String Data, Right Truncation" mean and how do I fix it?

I got around the issue by using a convert on the "?", so my code looks like convert(char(50),?) and that got rid of the truncation error.

What are best practices for multi-language database design?

I find this type of approach works for me:

Product     ProductDetail        Country
=========   ==================   =========
ProductId   ProductDetailId      CountryId
- etc -     ProductId            CountryName
            CountryId            Language
            ProductName          - etc -
            - etc -

The ProductDetail table holds all the translations (for product name, description etc..) in the languages you want to support. Depending on your app's requirements, you may wish to break the Country table down to use regional languages too.

Do we need to execute Commit statement after Update in SQL Server

Sql server unlike oracle does not need commits unless you are using transactions.
Immediatly after your update statement the table will be commited, don't use the commit command in this scenario.

Add one year in current date PYTHON

Look at this:


import datetime

def addYears(date, years):
    result = date + datetime.timedelta(366 * years)
    if years > 0:
        while result.year - date.year > years or date.month < result.month or <
            result += datetime.timedelta(-1)
    elif years < 0:
        while result.year - date.year < years or date.month > result.month or >
            result += datetime.timedelta(1)
    print "input: %s output: %s" % (date, result)
    return result

Example usage:

addYears(,1,1), -1)
addYears(,1,1), 0)
addYears(,1,1), 1)
addYears(,1,1), -10)
addYears(,1,1), 0)
addYears(,1,1), 10)

And output of this example:

input: 2012-01-01 output: 2011-01-01
input: 2012-01-01 output: 2012-01-01
input: 2012-01-01 output: 2013-01-01
input: 2012-01-01 output: 2002-01-01
input: 2012-01-01 output: 2012-01-01
input: 2012-01-01 output: 2022-01-01

Oracle PL/SQL string compare issue

I compare strings using = and not <>. I've found out that in this context = seems to work in more reasonable fashion than <>. I have specified that two empty (or NULL) strings are equal. The real implementation returns PL/SQL boolean, but here I changed that to pls_integer (0 is false and 1 is true) to be able easily demonstrate the function.

create or replace function is_equal(a in varchar2, b in varchar2)
return pls_integer as
  if a is null and b is null then
    return 1;
  end if;

  if a = b then
    return 1;
  end if;

  return 0;
show errors

  /* Prints 0 */
  dbms_output.put_line(is_equal('AAA', 'BBB'));
  dbms_output.put_line(is_equal('AAA', null));
  dbms_output.put_line(is_equal(null, 'BBB'));
  dbms_output.put_line(is_equal('AAA', ''));
  dbms_output.put_line(is_equal('', 'BBB'));

  /* Prints 1 */
  dbms_output.put_line(is_equal(null, null));
  dbms_output.put_line(is_equal(null, ''));
  dbms_output.put_line(is_equal('', ''));
  dbms_output.put_line(is_equal('AAA', 'AAA'));

Pipe output and capture exit status in Bash

The simplest way to do this in plain bash is to use process substitution instead of a pipeline. There are several differences, but they probably don't matter very much for your use case:

  • When running a pipeline, bash waits until all processes complete.
  • Sending Ctrl-C to bash makes it kill all the processes of a pipeline, not just the main one.
  • The pipefail option and the PIPESTATUS variable are irrelevant to process substitution.
  • Possibly more

With process substitution, bash just starts the process and forgets about it, it's not even visible in jobs.

Mentioned differences aside, consumer < <(producer) and producer | consumer are essentially equivalent.

If you want to flip which one is the "main" process, you just flip the commands and the direction of the substitution to producer > >(consumer). In your case:

command > >(tee out.txt)


$ { echo "hello world"; false; } > >(tee out.txt)
hello world
$ echo $?
$ cat out.txt
hello world

$ echo "hello world" > >(tee out.txt)
hello world
$ echo $?
$ cat out.txt
hello world

As I said, there are differences from the pipe expression. The process may never stop running, unless it is sensitive to the pipe closing. In particular, it may keep writing things to your stdout, which may be confusing.

Is mathematics necessary for programming?

If you find the subject fascinating enough to post this, just go ahead and start learning. The rest will come naturally.

ERROR 1148: The used command is not allowed with this MySQL version

All of this didn't solve it for me on my brand new Ubuntu 15.04.

I removed the LOCAL and got this command:


but then I got:

MySQL said: File 'A.txt' not found (Errcode: 13 - Permission denied)

That led me to this answer from Nelson to another question on stackoverflow which solved the issue for me!

Typescript: How to define type for a function callback (as any function type, not universal any) used in a method parameter

There are four abstract function types, you can use them separately when you know your function will take an argument(s) or not, will return a data or not.

export declare type fEmptyVoid = () => void;
export declare type fEmptyReturn = () => any;
export declare type fArgVoid = (...args: any[]) => void;
export declare type fArgReturn = (...args: any[]) => any;

like this:

public isValid: fEmptyReturn = (): boolean => true;
public setStatus: fArgVoid = (status: boolean): void => this.status = status;

For use only one type as any function type we can combine all abstract types together, like this:

export declare type fFunction = fEmptyVoid | fEmptyReturn | fArgVoid | fArgReturn;

then use it like:

public isValid: fFunction = (): boolean => true;
public setStatus: fFunction = (status: boolean): void => this.status = status;

In the example above everything is correct. But the usage example in bellow is not correct from the point of view of most code editors.

// you can call this function with any type of function as argument
public callArgument(callback: fFunction) {

    // but you will get editor error if call callback argument like this

Correct call for editors is like this:

public callArgument(callback: fFunction) {

    // pay attention in this part, for fix editor(s) error
    (callback as fFunction)();

Dynamically adding elements to ArrayList in Groovy

What you actually created with:

MyType[] list = []

Was fixed size array (not list) with size of 0. You can create fixed size array of size for example 4 with:

MyType[] array = new MyType[4]

But there's no add method of course.

If you create list with def it's something like creating this instance with Object (You can read more about def here). And [] creates empty ArrayList in this case.

So using def list = [] you can then append new items with add() method of ArrayList

list.add(new MyType())

Or more groovy way with overloaded left shift operator:

list << new MyType() 

Get Selected value from dropdown using JavaScript


var e = document.getElementById("mySelect");
var selectedOp = e.options[e.selectedIndex].text;

Expand and collapse with angular js

You can solve this fully in the html:

  <input ng-model=collapse type=checkbox>Title
  <div ng-show=collapse>
     Only shown when checkbox is clicked

This also works well with ng-repeat since it will create a local scope for each member.

  <tbody ng-repeat='m in members'>
       <td><input type=checkbox ng-model=collapse></td>
    <tr ng-show=collapse>
      <td> </td>
      <td>{{ m.content }}</td>

Be aware that even though a repeat has its own scope, initially it will inherit the value from collapse from super scopes. This allows you to set the initial value in one place but it can be surprising.

You can of course restyle the checkbox. See

Updated fiddle: Original fiddle used closing </input> tags to add the HTML text label instead of using <label> tags.

How to determine the longest increasing subsequence using dynamic programming?

I have implemented LIS in java using Dynamic Programming and Memoization. Along with the code I have done complexity calculation i.e. why it is O(n Log(base2) n). As I feel theoretical or logical explanations are good but practical demonstration is always better for understanding.


import java.util.HashMap;
import java.util.Map;

public class LongestIncreasingSequence {

    static int complexity = 0;

    public static void main(String ...args){

        int[] arr = {10, 22, 9, 33, 21, 50, 41, 60, 80};
        int n = arr.length;

        Map<Integer, Integer> memo = new HashMap<>();

        lis(arr, n, memo);

        //Display Code Begins
        int x = 0;
        System.out.format("Longest Increasing Sub-Sequence with size %S is -> ",memo.get(n));
        for(Map.Entry e : memo.entrySet()){

            if((Integer)e.getValue() > x){
                System.out.print(arr[(Integer)e.getKey()-1] + " ");
        System.out.format("%nAnd Time Complexity for Array size %S is just %S ", arr.length, complexity );
        System.out.format( "%nWhich is equivalent to O(n Log n) i.e. %SLog(base2)%S is %S",arr.length,arr.length, arr.length * Math.ceil(Math.log(arr.length)/Math.log(2)));
        //Display Code Ends


    static int lis(int[] arr, int n, Map<Integer, Integer> memo){

            memo.put(1, 1);
            return 1;

        int lisAti;
        int lisAtn = 1;

        for(int i = 1; i < n; i++){

                lisAti = memo.get(i);
            }else {
                lisAti = lis(arr, i, memo);

            if(arr[i-1] < arr[n-1] && lisAti +1 > lisAtn){
                lisAtn = lisAti +1;

        memo.put(n, lisAtn);
        return lisAtn;


While I ran the above code -

Longest Increasing Sub-Sequence with size 6 is -> 10 22 33 50 60 80 
And Time Complexity for Array size 9 is just 36 
Which is equivalent to O(n Log n) i.e. 9Log(base2)9 is 36.0
Process finished with exit code 0

Calculate a Running Total in SQL Server

The following will produce the required results.

SELECT a.SomeDate,
       SUM(b.SomeValue) AS RunningTotal
FROM TestTable a
CROSS JOIN TestTable b
WHERE (b.SomeDate <= a.SomeDate) 
GROUP BY a.SomeDate,a.SomeValue
ORDER BY a.SomeDate,a.SomeValue

Having a clustered index on SomeDate will greatly improve the performance.

Building and running app via Gradle and Android Studio is slower than via Eclipse

Solved mine with

File -> Settings -> Build, Execution, Deployment -> Build Tools -> Gradle -> Offline work

Gradle builds went from 8 minutes to 3 seconds.

Paste a multi-line Java String in Eclipse

You can use this Eclipse Plugin: This is a multi-line string editor popup. Place your caret in a string literal press ctrl-shift-alt-m and paste your text.

Count all occurrences of a string in lots of files with grep

You can add -R to search recursively (and avoid to use cat) and -I to ignore binary files.

grep -RIc string .

how to sort an ArrayList in ascending order using Collections and Comparator

Use the default version:


Of course this requires that your Elements implement Comparable, but the same holds true for the version you mentioned.

BTW: you should use generics in your code, that way you get compile-time errors if your class doesn't implement Comparable. And compile-time errors are much better than the runtime errors you'll get otherwise.

List<MyClass> list = new ArrayList<MyClass>();
// now fill up the list

// compile error here unless MyClass implements Comparable

Pass a PHP string to a JavaScript variable (and escape newlines)

function escapeJavaScriptText($string)
    return str_replace("\n", '\n', str_replace('"', '\"', addcslashes(str_replace("\r", '', (string)$string), "\0..\37'\\")));

How do I change the hover over color for a hover over table in Bootstrap?

This was the most simple way to do it imo and it worked for me.

.table-hover tbody tr:hover td {
    background: aqua;

Not sure why you would want to change the heading color to the same hover color as the rows but if you do then you can use the above solutions. If you just want t

How can I mix LaTeX in with Markdown?

What language are you using?

If you can use ruby, then maruku can be configured to process maths using various latex->MathML converters. Instiki uses this. It's also possible to extend PHPMarkdown to use itex2MML as well to convert maths. Basically, you insert extra steps in the Markdown engine at the appropriate points.

So with ruby and PHP, this is done. I guess these solutions could also be adapted to other languages - I've gotten the itex2MML extension to produce perl bindings as well.

Create a GUID in Java

Just to extend Mark Byers's answer with an example:

import java.util.UUID;

public class RandomStringUUID {
    public static void main(String[] args) {
        UUID uuid = UUID.randomUUID();
        System.out.println("UUID=" + uuid.toString() );

How to use android emulator for testing bluetooth application?

Download Androidx86 from this This is an iso file, so you'd
need something like VMWare or VirtualBox to run it When creating the virtual machine, you need to set the type of guest OS as Linux instead of Other.

After creating the virtual machine set the network adapter to 'Bridged'. · Start the VM and select 'Live CD VESA' at boot.

Now you need to find out the IP of this VM. Go to terminal in VM (use Alt+F1 & Alt+F7 to toggle) and use the netcfg command to find this.

Now you need open a command prompt and go to your android install folder (on host). This is usually C:\Program Files\Android\android-sdk\platform-tools>.

Type adb connect IP_ADDRESS. There done! Now you need to add Bluetooth. Plug in your USB Bluetooth dongle/Bluetooth device.

In VirtualBox screen, go to Devices>USB devices. Select your dongle.

Done! now your Android VM has Bluetooth. Try powering on Bluetooth and discovering/paring with other devices.

Now all that remains is to go to Eclipse and run your program. The Android AVD manager should show the VM as a device on the list.

Alternatively, Under settings of the virtual machine, Goto serialports -> Port 1 check Enable serial port select a port number then select port mode as disconnected click ok. now, start virtual machine. Under Devices -> USB Devices -> you can find your laptop bluetooth listed. You can simply check the option and start testing the android bluetooth application .


Git fast forward VS no fast forward merge

It is possible also that one may want to have personalized feature branches where code is just placed at the end of day. That permits to track development in finer detail.

I would not want to pollute master development with non-working code, thus doing --no-ff may just be what one is looking for.

As a side note, it may not be necessary to commit working code on a personalized branch, since history can be rewritten git rebase -i and forced on the server as long as nobody else is working on that same branch.

How to set custom header in Volley Request

Here is setting headers from github sample:

StringRequest myReq = new StringRequest(Method.POST,
                        createMyReqErrorListener()) {

 protected Map<String, String> getParams() throws  {
                        Map<String, String> params = new HashMap<String, String>();
                        params.put("param1", num1);
                        params.put("param2", num2);
                        return params;

How to import popper.js?

Ways to get popper.js: Package, CDN, and Local file

The best way depends on whether you have a project with a package manager like npm.

Package manager
If you're using a package manager, use it to get popper.js like this:

npm install popper.js --save

For a prototype or playground environment (like or may just want a url to a CDN file:

note: Bootstrap 4 requires the versions under the umd path (more info on popper/bs4).

Local file

Just save one of the CDN files to use locally. For example, paste one of these URLs in a browser, then Save As... to get a local copy.

Module is not available, misspelled or forgot to load (but I didn't)

I have the same problem, but I resolved adding jquery.min.js before angular.min.js.

Python Replace \\ with \

In Python string literals, backslash is an escape character. This is also true when the interactive prompt shows you the value of a string. It will give you the literal code representation of the string. Use the print statement to see what the string actually looks like.

This example shows the difference:

>>> '\\'
>>> print '\\'

Save multiple sheets to .pdf

I recommend adding the following line after the export to PDF:


(where eg. Sheet1 is the single sheet you want to be active afterwards)

Leaving multiple sheets in a selected state may cause problems executing some code. (eg. unprotect doesn't function properly when multiple sheets are actively selected.)

How can I send large messages with Kafka (over 15MB)?

You need to adjust three (or four) properties:

  • Consumer side:fetch.message.max.bytes - this will determine the largest size of a message that can be fetched by the consumer.
  • Broker side: replica.fetch.max.bytes - this will allow for the replicas in the brokers to send messages within the cluster and make sure the messages are replicated correctly. If this is too small, then the message will never be replicated, and therefore, the consumer will never see the message because the message will never be committed (fully replicated).
  • Broker side: message.max.bytes - this is the largest size of the message that can be received by the broker from a producer.
  • Broker side (per topic): max.message.bytes - this is the largest size of the message the broker will allow to be appended to the topic. This size is validated pre-compression. (Defaults to broker's message.max.bytes.)

I found out the hard way about number 2 - you don't get ANY exceptions, messages, or warnings from Kafka, so be sure to consider this when you are sending large messages.

How do you make Vim unhighlight what you searched for?

Append the following line to the end of your .vimrc to prevent highlighting altogether:

set nohlsearch

How does DISTINCT work when using JPA and Hibernate

Depending on the underlying JPQL or Criteria API query type, DISTINCT has two meanings in JPA.

Scalar queries

For scalar queries, which return a scalar projection, like the following query:

List<Integer> publicationYears = entityManager
    "select distinct year(p.createdOn) " +
    "from Post p " +
    "order by year(p.createdOn)", Integer.class)
.getResultList();"Publication years: {}", publicationYears);

The DISTINCT keyword should be passed to the underlying SQL statement because we want the DB engine to filter duplicates prior to returning the result set:

    extract(YEAR FROM p.created_on) AS col_0_0_
    post p
    extract(YEAR FROM p.created_on)

-- Publication years: [2016, 2018]

Entity queries

For entity queries, DISTINCT has a different meaning.

Without using DISTINCT, a query like the following one:

List<Post> posts = entityManager
    "select p " +
    "from Post p " +
    "left join fetch p.comments " +
    "where p.title = :title", Post.class)
    "High-Performance Java Persistence eBook has been released!"
    "Fetched the following Post entity identifiers: {}",

is going to JOIN the post and the post_comment tables like this:

SELECT AS id1_0_0_, AS id1_1_1_,
       p.created_on AS created_2_0_0_,
       p.title AS title3_0_0_,
       pc.post_id AS post_id3_1_1_, AS review2_1_1_,
       pc.post_id AS post_id3_1_0__
FROM   post p
       post_comment pc ON
       p.title='High-Performance Java Persistence eBook has been released!'

-- Fetched the following Post entity identifiers: [1, 1]

But the parent post records are duplicated in the result set for each associated post_comment row. For this reason, the List of Post entities will contain duplicate Post entity references.

To eliminate the Post entity references, we need to use DISTINCT:

List<Post> posts = entityManager
    "select distinct p " +
    "from Post p " +
    "left join fetch p.comments " +
    "where p.title = :title", Post.class)
    "High-Performance Java Persistence eBook has been released!"
    "Fetched the following Post entity identifiers: {}",

But then DISTINCT is also passed to the SQL query, and that's not desirable at all:

SELECT DISTINCT AS id1_0_0_, AS id1_1_1_,
       p.created_on AS created_2_0_0_,
       p.title AS title3_0_0_,
       pc.post_id AS post_id3_1_1_, AS review2_1_1_,
       pc.post_id AS post_id3_1_0__
FROM   post p
       post_comment pc ON
       p.title='High-Performance Java Persistence eBook has been released!'
-- Fetched the following Post entity identifiers: [1]

By passing DISTINCT to the SQL query, the EXECUTION PLAN is going to execute an extra Sort phase which adds overhead without bringing any value since the parent-child combinations always return unique records because of the child PK column:

Unique  (cost=23.71..23.72 rows=1 width=1068) (actual time=0.131..0.132 rows=2 loops=1)
  ->  Sort  (cost=23.71..23.71 rows=1 width=1068) (actual time=0.131..0.131 rows=2 loops=1)
        Sort Key:,, p.created_on, pc.post_id,
        Sort Method: quicksort  Memory: 25kB
        ->  Hash Right Join  (cost=11.76..23.70 rows=1 width=1068) (actual time=0.054..0.058 rows=2 loops=1)
              Hash Cond: (pc.post_id =
              ->  Seq Scan on post_comment pc  (cost=0.00..11.40 rows=140 width=532) (actual time=0.010..0.010 rows=2 loops=1)
              ->  Hash  (cost=11.75..11.75 rows=1 width=528) (actual time=0.027..0.027 rows=1 loops=1)
                    Buckets: 1024  Batches: 1  Memory Usage: 9kB
                    ->  Seq Scan on post p  (cost=0.00..11.75 rows=1 width=528) (actual time=0.017..0.018 rows=1 loops=1)
                          Filter: ((title)::text = 'High-Performance Java Persistence eBook has been released!'::text)
                          Rows Removed by Filter: 3
Planning time: 0.227 ms
Execution time: 0.179 ms


To eliminate the Sort phase from the execution plan, we need to use the HINT_PASS_DISTINCT_THROUGH JPA query hint:

List<Post> posts = entityManager
    "select distinct p " +
    "from Post p " +
    "left join fetch p.comments " +
    "where p.title = :title", Post.class)
    "High-Performance Java Persistence eBook has been released!"
.setHint(QueryHints.HINT_PASS_DISTINCT_THROUGH, false)
    "Fetched the following Post entity identifiers: {}",

And now, the SQL query will not contain DISTINCT but Post entity reference duplicates are going to be removed:

SELECT AS id1_0_0_, AS id1_1_1_,
       p.created_on AS created_2_0_0_,
       p.title AS title3_0_0_,
       pc.post_id AS post_id3_1_1_, AS review2_1_1_,
       pc.post_id AS post_id3_1_0__
FROM   post p
       post_comment pc ON
       p.title='High-Performance Java Persistence eBook has been released!'
-- Fetched the following Post entity identifiers: [1]

And the Execution Plan is going to confirm that we no longer have an extra Sort phase this time:

Hash Right Join  (cost=11.76..23.70 rows=1 width=1068) (actual time=0.066..0.069 rows=2 loops=1)
  Hash Cond: (pc.post_id =
  ->  Seq Scan on post_comment pc  (cost=0.00..11.40 rows=140 width=532) (actual time=0.011..0.011 rows=2 loops=1)
  ->  Hash  (cost=11.75..11.75 rows=1 width=528) (actual time=0.041..0.041 rows=1 loops=1)
        Buckets: 1024  Batches: 1  Memory Usage: 9kB
        ->  Seq Scan on post p  (cost=0.00..11.75 rows=1 width=528) (actual time=0.036..0.037 rows=1 loops=1)
              Filter: ((title)::text = 'High-Performance Java Persistence eBook has been released!'::text)
              Rows Removed by Filter: 3
Planning time: 1.184 ms
Execution time: 0.160 ms

How to fix Error: laravel.log could not be opened?

Run following commands and you can add sudo at starting of command depends on your system:

chmod -R 775 storage/framework
chmod -R 775 storage/logs
chmod -R 775 bootstrap/cache 

Wait for a void async method

You don't really need to do anything manually, await keyword pauses the function execution until blah() returns.

private async void SomeFunction()
     var x = await LoadBlahBlah(); <- Function is not paused
     //rest of the code get's executed even if LoadBlahBlah() is still executing

private async Task<T> LoadBlahBlah()
     await DoStuff();  <- function is paused
     await DoMoreStuff();

T is type of object blah() returns

You can't really await a void function so LoadBlahBlah() cannot be void

How to use mongoimport to import csv

use :

mongoimport -d 'database_name' -c 'collection_name' --type csv --headerline --file filepath/file_name.csv

Mongoose (mongodb) batch insert?

Mongoose 4.4.0 now supports bulk insert

Mongoose 4.4.0 introduces --true-- bulk insert with the model method .insertMany(). It is way faster than looping on .create() or providing it with an array.


var rawDocuments = [/* ... */];

    .then(function(mongooseDocuments) {
         /* ... */
    .catch(function(err) {
        /* Error handling */


Book.insertMany(rawDocuments, function (err, mongooseDocuments) { /* Your callback function... */ });

You can track it on:

Revert to Eclipse default settings

Not even a single answer of the above let me able to get the original theme as I expected. I tried myself & got my default theme by changing the workspace. This led me to the original theme (same-to-same) that I used to saw when installing eclipse !

How do I assert equality on two classes without an equals method?

AssertJ assertions can be used to compare the values without #equals method properly overridden, e.g.:

import static org.assertj.core.api.Assertions.assertThat; 

// ...


Should I use 'border: none' or 'border: 0'?

Easiest Way to remove border with css

border: 0;

JavaScript - Get minutes between two dates

Subtracting 2 Date objects gives you the difference in milliseconds, e.g.:

var diff = Math.abs(new Date('2011/10/09 12:00') - new Date('2011/10/09 00:00'));

Math.abs is used to be able to use the absolute difference (so new Date('2011/10/09 00:00') - new Date('2011/10/09 12:00') gives the same result).

Dividing the result by 1000 gives you the number of seconds. Dividing that by 60 gives you the number of minutes. To round to whole minutes, use Math.floor or Math.ceil:

var minutes = Math.floor((diff/1000)/60);

In this example the result will be 720

Node.js: what is ENOSPC error and how to solve?

ENOSPC means that there is no space on the drive.

Perhaps /tmp is full? You can configure npm to use a different temp folder by setting npm config set tmp /path/to/some/other/dir, or maybe delete everything out of the /tmp folder.

Source: npm 1.1.21 cannot write, ENOSPC in npm's repo in github.

Note I solved my problem in the way that described in above source. However, see Murali Krishna's answer, which is more comprehensive.

error: Libtool library used but 'LIBTOOL' is undefined

Fixed it. I needed to run libtoolize in the directory, then re-run:

  • aclocal

  • autoheader

Calling a JavaScript function returned from an Ajax response

It is fully possible, and there are even some fairly legitimate use cases for this. Using the Prototype framework it's done as follows.

new Ajax.Updater('items', '/items.url', {
    parameters: { evalJS: true}

See documentation of the Ajax updater. The options are in the common options set. As usual, there are some caveats about where "this" points to, so read the fine print.

The JavaScript code will be evaluated upon load. If the content contains function myFunc(), you could really just say myFunc() afterwards. Maybe as follows.

if (window["myFunc"])

This checks if the function exists. Maybe someone has a better cross-browser way of doing that which works in Internet Explorer 6.

How do I remove a library from the arduino environment?

as of 1.8.X IDE C:\Users***\Documents\Arduino\Libraries\

How can I kill all sessions connecting to my oracle database?

Try trigger on logon

Insted of trying disconnect users you should not allow them to connect.

There is and example of such trigger.

    RAISE_APPLICATION_ERROR(-20003,'You are not allowed to connect to the database');

  IF (to_number(to_char(sysdate,'HH24'))< 6) and (to_number(to_char(sysdate,'HH24')) >18) THEN
    RAISE_APPLICATION_ERROR(-20005,'Logon only allowed during business hours');


How to get text from EditText?

If you are doing it before the setContentView() method call, then the values will be null.

This will result in null:


Button btn = (Button)findViewById(;
String text = (String) btn.getText();


while this will work fine:


Button btn = (Button)findViewById(;
String text = (String) btn.getText();

Adding link a href to an element using css

No. Its not possible to add link through css. But you can use jquery

$('.case').each(function() {
  var link = $(this).html();
  $(this).contents().wrap('<a href=""></a>');

Here the demo:

What does "javascript:void(0)" mean?

Web Developers use javascript:void(0) because it is the easiest way to prevent the default behavior of a tag. void(*anything*) returns undefined and it is a falsy value. and returning a falsy value is like return false in onclick event of a tag that prevents its default behavior.

So I think javascript:void(0) is the simplest way to prevent the default behavior of a tag.

Android, How to limit width of TextView (and add three dots at the end of text)?

you can do that by xml:

    android:maxLines="1" // or any number of lines you want

openCV program compile error " cannot open shared object file: No such file or directory" in ubuntu 12.04

You haven't put the shared library in a location where the loader can find it. look inside the /usr/local/opencv and /usr/local/opencv2 folders and see if either of them contains any shared libraries (files beginning in lib and usually ending in .so). when you find them, create a file called /etc/ and write to it the paths to the folders where the libraries are stored, one per line.

for example, if the libraries were stored under /usr/local/opencv/ then I would write this to my opencv.conf file:


Then run

sudo ldconfig -v

If you can't find the libraries, try running

sudo updatedb && locate

in a shell. You don't need to run updatedb if you've rebooted since compiling OpenCV.


About shared libraries on Linux:

About adding the OpenCV shared libraries:

How to determine a user's IP address in node

var ip = req.headers['x-forwarded-for'] || 
     req.connection.remoteAddress || 
     req.socket.remoteAddress ||
     (req.connection.socket ? req.connection.socket.remoteAddress : null);

Note that sometimes you can get more than one IP address in req.headers['x-forwarded-for']. Also, an x-forwarded-for header will not always be set which may throw an error.

The general format of the field is:

x-forwarded-for: client, proxy1, proxy2, proxy3

where the value is a comma+space separated list of IP addresses, the left-most being the original client, and each successive proxy that passed the request adding the IP address where it received the request from. In this example, the request passed through proxy1, proxy2, and then proxy3. proxy3 appears as remote address of the request.

This is the solution suggested by Arnav Gupta with a fix Martin has suggested below in the comments for cases when x-forwarded-for is not set :

var ip = (req.headers['x-forwarded-for'] || '').split(',').pop().trim() || 
         req.connection.remoteAddress || 
         req.socket.remoteAddress || 

Suggestion using modern JS:

  • processing x-forwarded-for only if set, if so, take the first address
  • other parameters use optional chaining (?.)
const parseIp = (req) =>
    (typeof req.headers['x-forwarded-for'] === 'string'
        && req.headers['x-forwarded-for'].split(',').shift())
    || req.connection?.remoteAddress
    || req.socket?.remoteAddress
    || req.connection?.socket?.remoteAddress

// =>

password for postgres

Set the default password in the .pgpass file. If the server does not save the password, it is because it is not set in the .pgpass file, or the permissions are open and the file is therefore ignored.

Read more about the password file here.

Also, be sure to check the permissions: on *nix systems the permissions on .pgpass must disallow any access to world or group; achieve this by the command chmod 0600 ~/.pgpass. If the permissions are less strict than this, the file will be ignored.

Have you tried logging-in using PGAdmin? You can save the password there, and modify the pgpass file.