Programs & Examples On #Ghostscriptsharp

How should a model be structured in MVC?

In my case I have a database class that handle all the direct database interaction such as querying, fetching, and such. So if I had to change my database from MySQL to PostgreSQL there won't be any problem. So adding that extra layer can be useful.

Each table can have its own class and have its specific methods, but to actually get the data, it lets the database class handle it:

File Database.php

class Database {
    private static $connection;
    private static $current_query;

    public static function query($sql) {
        if (!self::$connection){
        self::$current_query = $sql;
        $result = mysql_query($sql,self::$connection);

        if (!$result){
            // throw custom error
            // The query failed for some reason. here is query :: self::$current_query
            $error = new Error(2,"There is an Error in the query.\n<b>Query:</b>\n{$sql}\n");
        return $result;

    public static function find_by_sql($sql){
        if (!is_string($sql))
            return false;

        $result_set = self::query($sql);
        $obj_arr = array();
        while ($row = self::fetch_array($result_set))
            $obj_arr[] = self::instantiate($row);
        return $obj_arr;

Table object classL

class DomainPeer extends Database {

    public static function getDomainInfoList() {
        $sql = 'SELECT ';
        $sql .='d.`id`,';
        $sql .='d.`name`,';
        $sql .='d.`shortName`,';
        $sql .='d.`created_at`,';
        $sql .='d.`updated_at`,';
        $sql .='count( as queries ';
        $sql .='FROM `domains` d ';
        $sql .='LEFT JOIN queries q on q.domainId = ';
        $sql .='GROUP BY';
        return self::find_by_sql($sql);


I hope this example helps you create a good structure.

What is the difference between SQL, PL-SQL and T-SQL?

1. SQL or Structured Query Language was developed by IBM for their product "System R".

Later ANSI made it as a Standard on which all Query Languages are based upon and have extended this to create their own DataBase Query Language suits. The first standard was SQL-86 and latest being SQL:2016

2. T-SQL or Transact-SQL was developed by Sybase and later co-owned by Microsoft SQL Server.

3. PL/SQL or Procedural Language/SQL was Oracle Database, known as "Relation Software" that time.

I've documented this in my blog post.

Python-Requests close http connection

I came to this question looking to solve the "too many open files" error, but I am using requests.session() in my code. A few searches later and I came up with an answer on the Python Requests Documentation which suggests to use the with block so that the session is closed even if there are unhandled exceptions:

with requests.Session() as s:

If you're not using Session you can actually do the same thing:

with requests.get('', stream=True) as r:
    # Do something

Efficiently finding the last line in a text file

Not the straight forward way, but probably much faster than a simple Python implementation:

line = subprocess.check_output(['tail', '-1', filename])

jQuery UI Sortable, then write order into a database

The jQuery UI sortable feature includes a serialize method to do this. It's quite simple, really. Here's a quick example that sends the data to the specified URL as soon as an element has changes position.

    axis: 'y',
    update: function (event, ui) {
        var data = $(this).sortable('serialize');

        // POST to server using $.post or $.ajax
            data: data,
            type: 'POST',
            url: '/your/url/here'

What this does is that it creates an array of the elements using the elements id. So, I usually do something like this:

<ul id="sortable">
   <li id="item-1"></li>
   <li id="item-2"></li>

When you use the serialize option, it will create a POST query string like this: item[]=1&item[]=2 etc. So if you make use - for example - your database IDs in the id attribute, you can then simply iterate through the POSTed array and update the elements' positions accordingly.

For example, in PHP:

$i = 0;

foreach ($_POST['item'] as $value) {
    // Execute statement:
    // UPDATE [Table] SET [Position] = $i WHERE [EntityId] = $value

Example on jsFiddle.

How to fix the Hibernate "object references an unsaved transient instance - save the transient instance before flushing" error

For the sake of completeness: A


with message

object references an unsaved transient instance - save the transient instance before flushing

will also occur when you try to persist / merge an entity with a reference to another entity which happens to be detached.

Command /usr/bin/codesign failed with exit code 1

This issue occured when I added a folder named "Resources" as "Create folder references", and when I renamed "Resources" to another random name, this issue disappeared.

Hope it will help.

sql searching multiple words in a string

If you care about the sequence of the terms, you may consider using a syntax like

select * from T where C like'%David%Moses%Robi%'

Failed to add the host to the list of know hosts

Okay so ideal permissions look like this
For ssh directory (You can get this by typing ls -ld ~/.ssh/)
drwx------ 2 oroborus oroborus 4096 Nov 28 12:05 /home/oroborus/.ssh/

d means directory, rwx means the user oroborus has read write and execute permission. Here oroborus is my computer name, you can find yours by echoing $USER. The second oroborus is actually the group. You can read more about what does each field mean here. It is very important to learn this because if you are working on ubuntu/osx or any Linux distro chances are you will encounter it again.

Now to make your permission look like this, you need to type
sudo chmod 700 ~/.ssh

7 in binary is 111 which means read 1 write 1 and execute 1, you can decode 6 by similar logic means only read-write permissions

You have given your user read write and execute permissions. Make sure your file permissions look like this.

total 20
-rw------- 1 oroborus oroborus  418 Nov  8  2014 authorized_keys
-rw------- 1 oroborus oroborus   34 Oct 19 14:25 config
-rw------- 1 oroborus oroborus 1679 Nov 15  2015 id_rsa
-rw------- 1 oroborus oroborus  418 Nov 15  2015
-rw-r--r-- 1 oroborus root      222 Nov 28 12:12 known_hosts

You have given here read-write permission to your user here for all files. You can see this by typing ls -l ~/.ssh/

This issue occurs because ssh is a program is trying to write to a file called known_hosts in its folder. While writing if it knows that it doesn't have sufficient permissions it will not write in that file and hence fail. This is my understanding of the issue, more knowledgeable people can throw more light in this. Hope it helps

Having both a Created and Last Updated timestamp columns in MySQL 4.0

You can have them both, just take off the "CURRENT_TIMESTAMP" flag on the created field. Whenever you create a new record in the table, just use "NOW()" for a value.


On the contrary, remove the 'ON UPDATE CURRENT_TIMESTAMP' flag and send the NOW() for that field. That way actually makes more sense.

How to stop an unstoppable zombie job on Jenkins without restarting the server?

Go to "Manage Jenkins" > "Script Console" to run a script on your server to interrupt the hanging thread.

You can get all the live threads with Thread.getAllStackTraces() and interrupt the one that's hanging.

Thread.getAllStackTraces().keySet().each() {
  t -> if (t.getName()=="YOUR THREAD NAME" ) {   t.interrupt();  }


The above solution using threads may not work on more recent Jenkins versions. To interrupt frozen pipelines refer to this solution (by alexandru-bantiuc) instead and run:

                        new"Aborting build")

How to upload files on server folder using jsp

I found the similar problem and found the solution and i have blogged about how to upload the file using JSP , In that example i have used the absolute path. Note that if you want to route to some other URL based location you can put a ESB like WSO2 ESB

How to resolve this System.IO.FileNotFoundException

Check all the references carefully

  • Version remains same on target machine and local machine
  • If assembly is referenced from GAC, ensure that proper version is loaded

For me cleaning entire solution by deleting manually, updating (removing and adding) references again with version in sync with target machine and then building with with Copy Local > False for GAC assemblies solves the problem.

How to create a shared library with cmake?

This minimal CMakeLists.txt file compiles a simple shared library:

cmake_minimum_required(VERSION 2.8)

project (test)

add_library(test SHARED src/test.cpp)

However, I have no experience copying files to a different destination with CMake. The file command with the COPY/INSTALL signature looks like it might be useful.

SSLHandshakeException: No subject alternative names present

Thanks,Bruno for giving me heads up on Common Name and Subject Alternative Name. As we figured out certificate was generated with CN with DNS name of network and asked for regeneration of new certificate with Subject Alternative Name entry i.e. san=ip: which is the actual solution.

But, we managed to find out a workaround with which we can able to run on development phase. Just add a static block in the class from which we are making ssl connection.

static {
    HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier()
            public boolean verify(String hostname, SSLSession session)
                // ip address of the service URL(like.
                if (hostname.equals(""))
                    return true;
                return false;

If you happen to be using Java 8, there is a much slicker way of achieving the same result:

static {
    HttpsURLConnection.setDefaultHostnameVerifier((hostname, session) -> hostname.equals(""));

Convert a python 'type' object to a string

print("My type is %s" % type(someObject)) # the type in python


print("My type is %s" % type(someObject).__name__) # the object's type (the class you defined)

How do I remove quotes from a string?

str_replace('"', "", $string);
str_replace("'", "", $string);

I assume you mean quotation marks?

Otherwise, go for some regex, this will work for html quotes for example:

preg_replace("/<!--.*?-->/", "", $string);

C-style quotes:

preg_replace("/\/\/.*?\n/", "\n", $string);

CSS-style quotes:

preg_replace("/\/*.*?\*\//", "", $string);

bash-style quotes:

preg-replace("/#.*?\n/", "\n", $string);

Etc etc...

favicon.png vs favicon.ico - why should I use PNG instead of ICO?

Answer replaced (and turned Community Wiki) due to numerous updates and notes from various others in this thread:

  • ICOs and PNGs both allow full alpha channel based transparency
  • ICO allows for backwards compatibility to older browsers (e.g. IE6)
  • PNG probably has broader tooling support for transparency, but you can find tools to create alpha-channel ICOs as well, such as the Dynamic Drive tool and Photoshop plugin mentioned by @mercator.

Feel free to consult the other answers here for more details.

Getting number of days in a month

  int month = Convert.ToInt32(ddlMonth.SelectedValue);/*Store month Value From page*/
  int year = Convert.ToInt32(txtYear.Value);/*Store Year Value From page*/
  int days = System.DateTime.DaysInMonth(year, month); /*this will store no. of days for month, year that we store*/

How to style HTML5 range input to have different color before and after slider?

input type="range" min="0" max="50" value="0"  style="margin-left: 6%;width: 88%;background-color: whitesmoke;"

above code changes range input style.....

Draw a connecting line between two elements

VisJS supports this with its Arrows example, that supports draggable elements.

It also supports editable connections, with its Interaction Events example.

Importing CommonCrypto in a Swift framework

It happened the same to me after updating Xcode. I tried everything I can do such as reinstalling cocoapods and cleaning the project, but it didn't work. Now it's been solved after restart the system.

Appending to 2D lists in Python

Came here to see how to append an item to a 2D array, but the title of the thread is a bit misleading because it is exploring an issue with the appending.

The easiest way I found to append to a 2D list is like this:



This will result in an entry with the 2 variables var_1, var_2. Hope this helps!

How to find cube root using Python?

You could use x ** (1. / 3) to compute the (floating-point) cube root of x.

The slight subtlety here is that this works differently for negative numbers in Python 2 and 3. The following code, however, handles that:

def is_perfect_cube(x):
    x = abs(x)
    return int(round(x ** (1. / 3))) ** 3 == x

print(is_perfect_cube(2146689000)) # no other currently posted solution
                                   # handles this correctly

This takes the cube root of x, rounds it to the nearest integer, raises to the third power, and finally checks whether the result equals x.

The reason to take the absolute value is to make the code work correctly for negative numbers across Python versions (Python 2 and 3 treat raising negative numbers to fractional powers differently).

Style disabled button with CSS

I think you should be able to select a disabled button using the following:

button[disabled=disabled], button:disabled {
    // your css rules

Git diff against a stash

See the most recent stash:

git stash show -p

See an arbitrary stash:

git stash show -p stash@{1}

From the git stash manpages:

By default, the command shows the diffstat, but it will accept any format known to git diff (e.g., git stash show -p stash@{1} to view the second most recent stash in patch form).

typescript - cloning object

Add "lodash.clonedeep": "^4.5.0" to your package.json. Then use like this:

import * as _ from 'lodash';


const copy = _.cloneDeep(original)

How to disable right-click context-menu in JavaScript

If your page really relies on the fact that people won't be able to see that menu, you should know that modern browsers (for example Firefox) let the user decide if he really wants to disable it or not. So you have no guarantee at all that the menu would be really disabled.

How to name variables on the fly?

Use assign:

assign(paste("orca", i, sep = ""), list_name[[i]])

grep --ignore-case --only

This is a known bug on the initial 2.5.1, and has been fixed in early 2007 (Redhat 2.5.1-5) according to the bug reports. Unfortunately Apple is still using 2.5.1 even on Mac OS X 10.7.2.

You could get a newer version via Homebrew (3.0) or MacPorts (2.26) or fink (3.0-1).

Edit: Apparently it has been fixed on OS X 10.11 (or maybe earlier), even though the grep version reported is still 2.5.1.

How to enter command with password for git pull?

I did not find the answer to my question after searching Google & stackoverflow for a while so I would like to share my solution here.

git config --global credential.helper "/bin/bash /"
echo '#!/bin/bash' > /
echo "sleep 1" >> /
echo "echo username=$SERVICE_USER" >> /
echo "echo password=$SERVICE_PASS" >> /

# to test it
git clone

I did it for Windows too. Full answer here

How to do this in Laravel, subquery where in

You can use Eloquent in different queries and make things easier to understand and mantain:

$productCategory = ProductCategory::whereIn('category_id', ['223', '15'])
                   ->select('product_id'); //don't need ->get() or ->first()

and then we put all together:

Products::whereIn('id', $productCategory)
          ->where('active', 1)
          ->select('id', 'name', 'img', 'safe_name', 'sku', 'productstatusid')
          ->get();//runs all queries at once

This will generate the same query that you wrote in your question.

SQL set values of one column equal to values of another column in the same table

I don't think that other example is what you're looking for. If you're just updating one column from another column in the same table you should be able to use something like this.

update some_table set null_column = not_null_column where null_column is null

How do I add an image to a JButton

You put your image in resources folder and use follow code:

JButton btn = new JButton("");
btn.setIcon(new ImageIcon(Class.class.getResource("/resources/img.png")));

Check if a JavaScript string is a URL

This is defiantly not the most effective approach, but it is readable and easy to form to whatever you need. And it's easier to add regex/complexity from here. So here is a very pragmatic approach

const validFirstBits = ["ftp://", "http://", "https://", "www."];
const invalidPatterns = [" ", "//.", ".."];

export function isUrl(word) {
// less than
if (!word || word.length < 8) return false;

// Let's check and see, if our candidate starts with some of our valid first bits
const firstBitIsValid = validFirstBits.some(bit => word.indexOf(bit) === 0);
if (!firstBitIsValid) return false;

const hasInvalidPatterns = invalidPatterns.some(
    pattern => word.indexOf(pattern) !== -1,

if (hasInvalidPatterns) return false;

const dotSplit = word.split(".");
if (dotSplit.length > 1) {
    const lastBit = dotSplit.pop(); // string or undefined
    if (!lastBit) return false;
    const length = lastBit.length;
    const lastBitIsValid =
        length > 1 || (length === 1 && !isNaN(parseInt(lastBit)));
    return !!lastBitIsValid;

    return false;


import { isUrl } from "./foo";

describe("Foo", () => {
    test("should validate correct urls correctly", function() {
        const validUrls = [

        validUrls.forEach(url => {
            expect(isUrl(url) && url).toEqual(url);

    test("should validate invalid urls correctly", function() {
        const inValidUrls = [

        inValidUrls.forEach(url => {
            expect(!isUrl(url) && url).toEqual(url);

jQuery-UI datepicker default date

If you want to update the highlighted day to a different day based on some server time, you can override the Date Picker code to allow for a new custom option named localToday or whatever you'd like to name it.

A small tweak to the selected answer in jQuery UI DatePicker change highlighted "today" date

// Get users 'today' date
var localToday = new Date();
localToday.setDate(tomorrow.getDate()+1); // tomorrow

// Pass the today date to datepicker
$( "#datepicker" ).datepicker({
    showButtonPanel: true,
    localToday: localToday    // This option determines the highlighted today date

I've overridden 2 datepicker methods to conditionally use a new setting for the "today" date instead of a new Date(). The new setting is called localToday.

Override $.datepicker._gotoToday and $.datepicker._generateHTML like this:

$.datepicker._gotoToday = function(id) {
    /* ... */
    var date = inst.settings.localToday || new Date()
    /* ... */

$.datepicker._generateHTML = function(inst) {
    /* ... */
    tempDate = inst.settings.localToday || new Date()
    /* ... */

Here's a demo which shows the full code and usage:

How to list installed packages from a given repo using yum


yum list installed | grep reponame

On one of my servers:

yum list installed | grep remi
ImageMagick2.x86_64                       installed
memcache.x86_64                          1.4.5-2.el5.remi             installed
mysql.x86_64                              5.1.54-1.el5.remi            installed
mysql-devel.x86_64                        5.1.54-1.el5.remi            installed
mysql-libs.x86_64                         5.1.54-1.el5.remi            installed
mysql-server.x86_64                       5.1.54-1.el5.remi            installed
mysqlclient15.x86_64                      5.0.67-1.el5.remi            installed
php.x86_64                                5.3.5-1.el5.remi             installed
php-cli.x86_64                            5.3.5-1.el5.remi             installed
php-common.x86_64                         5.3.5-1.el5.remi             installed
php-domxml-php4-php5.noarch               1.21.2-1.el5.remi            installed
php-fpm.x86_64                            5.3.5-1.el5.remi             installed
php-gd.x86_64                             5.3.5-1.el5.remi             installed
php-mbstring.x86_64                       5.3.5-1.el5.remi             installed
php-mcrypt.x86_64                         5.3.5-1.el5.remi             installed
php-mysql.x86_64                          5.3.5-1.el5.remi             installed
php-pdo.x86_64                            5.3.5-1.el5.remi             installed
php-pear.noarch                           1:1.9.1-6.el5.remi           installed
php-pecl-apc.x86_64                       3.1.6-1.el5.remi             installed
php-pecl-imagick.x86_64                   3.0.1-1.el5.remi.1           installed
php-pecl-memcache.x86_64                  3.0.5-1.el5.remi             installed
php-pecl-xdebug.x86_64                    2.1.0-1.el5.remi             installed
php-soap.x86_64                           5.3.5-1.el5.remi             installed
php-xml.x86_64                            5.3.5-1.el5.remi             installed
remi-release.noarch                       5-8.el5.remi                 installed

It works.

Why does ASP.NET webforms need the Runat="Server" attribute?

My suspicion is that it has to do with how server-side controls are identified during processing. Rather than having to check every control at runtime by name to determine whether server-side processing needs to be done, it does a selection on the internal node representation by tag. The compiler checks to make sure that all controls that require server tags have them during the validation step.

How to submit a form using PhantomJS

I figured it out. Basically it's an async issue. You can't just submit and expect to render the subsequent page immediately. You have to wait until the onLoad event for the next page is triggered. My code is below:

var page = new WebPage(), testindex = 0, loadInProgress = false;

page.onConsoleMessage = function(msg) {

page.onLoadStarted = function() {
  loadInProgress = true;
  console.log("load started");

page.onLoadFinished = function() {
  loadInProgress = false;
  console.log("load finished");

var steps = [
  function() {
    //Load Login Page"");
  function() {
    //Enter Credentials
    page.evaluate(function() {

      var arr = document.getElementsByClassName("login-form");
      var i;

      for (i=0; i < arr.length; i++) { 
        if (arr[i].getAttribute('method') == "POST") {

  function() {
    page.evaluate(function() {
      var arr = document.getElementsByClassName("login-form");
      var i;

      for (i=0; i < arr.length; i++) {
        if (arr[i].getAttribute('method') == "POST") {

  function() {
    // Output content of page to stdout after form has been submitted
    page.evaluate(function() {

interval = setInterval(function() {
  if (!loadInProgress && typeof steps[testindex] == "function") {
    console.log("step " + (testindex + 1));
  if (typeof steps[testindex] != "function") {
    console.log("test complete!");
}, 50);

Load HTML File Contents to Div [without the use of iframes]

Wow, from all the framework-promotional answers you'd think this was something JavaScript made incredibly difficult. It isn't really.

var xhr= new XMLHttpRequest();'GET', 'x.html', true);
xhr.onreadystatechange= function() {
    if (this.readyState!==4) return;
    if (this.status!==200) return; // or whatever error handling you want
    document.getElementById('y').innerHTML= this.responseText;

If you need IE<8 compatibility, do this first to bring those browsers up to speed:

if (!window.XMLHttpRequest && 'ActiveXObject' in window) {
    window.XMLHttpRequest= function() {
        return new ActiveXObject('MSXML2.XMLHttp');

Note that loading content into the page with scripts will make that content invisible to clients without JavaScript available, such as search engines. Use with care, and consider server-side includes if all you want is to put data in a common shared file.

Dropdown select with images

I am a little to late on this, but you can do this using a simple bootstrap drop down and then do your code on select change event in any language or framework. (This is just a very basic solution, for other people like me who are just starting out and looking for a solution for a small simple project.)

<div class="dropdown">
    <button class="btn btn-default dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="true">
        Select Image
        <span class="caret"></span>
    <ul class="dropdown-menu" aria-labelledby="dropdownMenu1">
        <li> <a style="background-image: url(../Content/Images/Backgrounds/background.png);height:100px;width:300px" class="img-thumbnail" href=""> </a></li>
        <li role="separator" class="divider"></li>
        <li> <a style="background-image: url(../Content/Images/Backgrounds/background.png);height:100px;width:300px" class="img-thumbnail" href=""> </a></li>

NSRange from Swift Range?

My solution is a string extension that first gets the swift range then get's the distance from the start of the string to the start and end of the substring.

These values are then used to calculate the start and length of the substring. We can then apply these values to the NSMakeRange constructor.

This solution works with substrings that consist of multiple words, which a lot of the solutions here using enumerateSubstrings let me down on.

extension String {

    func NSRange(of substring: String) -> NSRange? {
        // Get the swift range 
        guard let range = range(of: substring) else { return nil }

        // Get the distance to the start of the substring
        let start = distance(from: startIndex, to: range.lowerBound) as Int
        //Get the distance to the end of the substring
        let end = distance(from: startIndex, to: range.upperBound) as Int

        //length = endOfSubstring - startOfSubstring
        //start = startOfSubstring
        return NSMakeRange(start, end - start)


What happened to Lodash _.pluck?

Use instead of _.pluck. In the latest version the _.pluck has been removed.

Datagridview full row selection but get single cell value

In the CellClick event you can write following code

string value =

Using the bove code you will get value of the cell you cliked. If you want to get value of paricular column in the clicked row, just replace e.ColumnIndex with the column index you want

How to refresh activity after changing language (Locale) inside application

For Android 4.2 (API 17), you need to use android:configChanges="locale|layoutDirection" in your AndroidManifest.xml. See onConfigurationchanged is not called over jellybean(4.2.1)

Changing a specific column name in pandas DataFrame

What about?

df.columns.values[2] = "new_name"

differences in application/json and application/x-www-form-urlencoded

The first case is telling the web server that you are posting JSON data as in:

{ Name : 'John Smith', Age: 23}

The second option is telling the web server that you will be encoding the parameters in the URL as in:


Installing Python library from WHL file

From How do I install a Python package with a .whl file? [sic], How do I install a Python package USING a .whl file ?

For all Windows platforms:

1) Download the .WHL package install file.

2) Make Sure path [C:\Progra~1\Python27\Scripts] is in the system PATH string. This is for using both [pip.exe] and [easy-install.exe].

3) Make sure the latest version of pip.EXE is now installed. At this time of posting:

pip.EXE --version

  pip 9.0.1 from C:\PROGRA~1\Python27\lib\site-packages (python 2.7)

4) Run pip.EXE in an Admin command shell.

 - Open an Admin privileged command shell.

 > easy_install.EXE --upgrade  pip

 - Check the pip.EXE version:
 > pip.EXE --version

 pip 9.0.1 from C:\PROGRA~1\Python27\lib\site-packages (python 2.7)

 > pip.EXE install --use-wheel --no-index 
     --find-links="X:\path to wheel file\DownloadedWheelFile.whl"

Be sure to double-quote paths or path\filenames with embedded spaces in them ! Alternatively, use the MSW 'short' paths and filenames.

Install numpy on python3.3 - Install pip for python3

The normal way to install Python libraries is with pip. Your way of installing it for Python 3.2 works because it's the system Python, and that's the way to install things for system-provided Pythons on Debian-based systems.

If your Python 3.3 is system-provided, you should probably use a similar command. Otherwise you should probably use pip.

I took my Python 3.3 installation, created a virtualenv and run pip install in it, and that seems to have worked as expected:

$ virtualenv-3.3 testenv
$ cd testenv
$ bin/pip install numpy

$ bin/python3
Python 3.3.2 (default, Jun 17 2013, 17:49:21) 
[GCC 4.6.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy

Webpack not excluding node_modules

If you ran into this issue when using TypeScript, you may need to add skipLibCheck: true in your tsconfig.json file.

How to mount a single file in a volume

I had the same issue on Windows, Docker 18.06.1-ce-win73 (19507).

Removing and re-adding the shared drive via the Docker settings panel and everything worked again.

How to include external Python code to use in other files?

I would like to emphasize an answer that was in the comments that is working well for me. As mikey has said, this will work if you want to have variables in the included file in scope in the caller of 'include', just insert it as normal python. It works like an include statement in PHP. Works in Python 3.8.5. Happy coding!

Alternative #1

import textwrap 
from pathlib import Path

Alternative #2

with open('') as f: exec(

Regular expression to match any character being repeated more than 10 times

use the {10,} operator:

$: cat > testre

$: grep -E '={10,}' testre

javascript cell number validation

Mobile number Validation using Java Script, This link will provide demo and more information.

function isNumber(evt) {_x000D_
  evt = (evt) ? evt : window.event;_x000D_
  var charCode = (evt.which) ? evt.which : evt.keyCode;_x000D_
  if (charCode > 31 && (charCode < 48 || charCode > 57)) {_x000D_
    alert("Please enter only Numbers.");_x000D_
    return false;_x000D_
  return true;_x000D_
function ValidateNo() {_x000D_
  var phoneNo = document.getElementById('txtPhoneNo');_x000D_
  if (phoneNo.value == "" || phoneNo.value == null) {_x000D_
    alert("Please enter your Mobile No.");_x000D_
    return false;_x000D_
  if (phoneNo.value.length < 10 || phoneNo.value.length > 10) {_x000D_
    alert("Mobile No. is not valid, Please Enter 10 Digit Mobile No.");_x000D_
    return false;_x000D_
  alert("Success ");_x000D_
  return true;_x000D_
<input id="txtPhoneNo" type="text" onkeypress="return isNumber(event)" />_x000D_
<input type="button" value="Submit" onclick="ValidateNo();">

How to remove \n from a list element?

from this link:

you can use rstrip() method. Example

mystring = "hello\n"    

Can PHP cURL retrieve response headers AND body in a single request?

If you specifically want the Content-Type, there's a special cURL option to retrieve it:

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = curl_exec($ch);
$content_type = curl_getinfo($ch, CURLINFO_CONTENT_TYPE);

how do I get the bullet points of a <ul> to center with the text?

Add list-style-position: inside to the ul element. (example)

The default value for the list-style-position property is outside.

ul {_x000D_
    text-align: center;_x000D_
    list-style-position: inside;_x000D_

Another option (which yields slightly different results) would be to center the entire ul element:

.parent {_x000D_
  text-align: center;_x000D_
.parent > ul {_x000D_
  display: inline-block;_x000D_
<div class="parent">_x000D_

Aborting a shell script if any command returns a non-zero value

An expression like

dosomething1 && dosomething2 && dosomething3

will stop processing when one of the commands returns with a non-zero value. For example, the following command will never print "done":

cat nosuchfile && echo "done"
echo $?

Find a string between 2 known values

Without RegEx, with some must-have value checking

    public static string ExtractString(string soapMessage, string tag)
        if (string.IsNullOrEmpty(soapMessage))
            return soapMessage;

        var startTag = "<" + tag + ">";
        int startIndex = soapMessage.IndexOf(startTag);
        startIndex = startIndex == -1 ? 0 : startIndex + startTag.Length;
        int endIndex = soapMessage.IndexOf("</" + tag + ">", startIndex);
        endIndex = endIndex > soapMessage.Length || endIndex == -1 ? soapMessage.Length : endIndex;
        return soapMessage.Substring(startIndex, endIndex - startIndex);

How do I add an active class to a Link from React Router?

Answer updated with ES6:

import React, { Component } from 'react';
import { Link } from 'react-router'

class NavLink extends Component {
    render() {
        let isActive = this.context.router.isActive(, true);
        let className = isActive ? "active" : "";

        return (
            <li className={className}>
                <Link {...this.props}/>

NavLink.contextTypes = {
    router: React.PropTypes.object

export default NavLink;

Then use it as described above.

How to find the first and second maximum number?

OK I found it.


=large(array, k)

Array Required. The array or range of data for which you want to determine the k-th largest value.

K Required. The position (from the largest) in the array or cell range of data to return.

Append column to pandas dataframe

It seems in general you're just looking for a join:

> dat1 = pd.DataFrame({'dat1': [9,5]})
> dat2 = pd.DataFrame({'dat2': [7,6]})
> dat1.join(dat2)
   dat1  dat2
0     9     7
1     5     6

Disabling right click on images using jquery

In chrome and firefox the methods above didn't work unless I used 'live' instead of 'bind'.

This worked for me:

$('img').live('contextmenu', function(e){
    return false;

How to combine multiple inline style objects?

    const style1 = {
        backgroundColor: "#2196F3", 
    const style2 = {
        color: "white", 

    const someComponent = () => {
        return <div style={{ ...style1, ...style2 }}>This has 2 separate styles</div> 

Note the double curly brackets. The spread operator is your friend.

Using jquery to delete all elements with a given id

You should be using a class for multiple elements as an id is meant to be only a single element. To answer your question on the .each() syntax though, this is what it would look like:

$('#myID').each(function() {

Official JQuery documentation here.

How many spaces will Java String.trim() remove?

Javadoc for String has all the details. Removes white space (space, tabs, etc ) from both end and returns a new string.

Set focus on textbox in WPF

Another possible solution is to use FocusBehavior provided by free DevExpress MVVM Framework:

<TextBox Text="This control is focused on startup">

It allows you to focus a control when it's loaded, when a certain event is raised or a property is changed.

How do I make bootstrap table rows clickable?

May be you are trying to attach a function when table rows are clicked.

var table = document.getElementById("tableId");
var rows = table.getElementsByTagName("tr");
for (i = 0; i < rows.length; i++) {
    rows[i].onclick = functioname(); //call the function like this

Android "gps requires ACCESS_FINE_LOCATION" error, even though my manifest file contains this

My simple solution is this

if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) ==
        PackageManager.PERMISSION_GRANTED &&
        ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) ==
        PackageManager.PERMISSION_GRANTED) {
} else {
    Toast.makeText(this, R.string.error_permission_map, Toast.LENGTH_LONG).show();

or you can open permission dialog in else like this

} else {
   ActivityCompat.requestPermissions(this, new String[] {
      Manifest.permission.ACCESS_COARSE_LOCATION }, 

Creating a UICollectionView programmatically

For Swift 2.0

Instead of implementing the methods that are required to draw the CollectionViewCells:

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
        return CGSizeMake(50, 50);

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets
        return UIEdgeInsetsMake(5, 5, 5, 5); //top,left,bottom,right

Use UICollectionViewFlowLayout

func createCollectionView() {
    let flowLayout = UICollectionViewFlowLayout()

    // Now setup the flowLayout required for drawing the cells
    let space = 5.0 as CGFloat

    // Set view cell size
    flowLayout.itemSize = CGSizeMake(50, 50)

    // Set left and right margins
    flowLayout.minimumInteritemSpacing = space

    // Set top and bottom margins
    flowLayout.minimumLineSpacing = space

    // Finally create the CollectionView
    let collectionView = UICollectionView(frame: CGRectMake(10, 10, 300, 400), collectionViewLayout: flowLayout)

    // Then setup delegates, background color etc.
    collectionView?.dataSource = self
    collectionView?.delegate = self
    collectionView?.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: "cellID")
    collectionView?.backgroundColor = UIColor.whiteColor()

Then implement the UICollectionViewDataSource methods as required:

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 20;
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    var cell:UICollectionViewCell=collectionView.dequeueReusableCellWithReuseIdentifier("collectionCell", forIndexPath: indexPath) as UICollectionViewCell;
    cell.backgroundColor = UIColor.greenColor();
    return cell;
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1

How to Remove Array Element and Then Re-Index Array?

In addition to xzyfer's answer

The function

function custom_unset(&$array=array(), $key=0) {

        // remove item at index

        // 'reindex' array
        $array = array_values($array);

        //$array = array_merge($array); 

    return $array;



custom_unset($my_array, 1);


 array(2) {
    string(5) "test0"
    string(5) "test2"

How can I get Android Wifi Scan Results into a list?

refer below link for getting ScanResult with redundant ssid removed from the list

duplicate SSID in scanning wifi result

Creating an R dataframe row-by-row

This is a silly example of how to use,) on the output of Map() [which is similar to lapply()]

> DF <-,Map(function(x) data.frame(a=x,b=x+1),x=1:3))
> DF
  x y
1 1 2
2 2 3
3 3 4
> class(DF)
[1] "data.frame"

I use this construct quite often.

Creating a singleton in Python

This answer is likely not what you're looking for. I wanted a singleton in the sense that only that object had its identity, for comparison to. In my case it was being used as a Sentinel Value. To which the answer is very simple, make any object mything = object() and by python's nature, only that thing will have its identity.

MyNone = object()  # The singleton

for item in my_list:
    if item is MyNone:  # An Example identity comparison
        raise StopIteration

Validate email address textbox using JavaScript

If you wish to allow accent (see RFC 5322) and allow new domain extension like .quebec. use this expression:

  • The '\u00C0-\u017F' part is for alowing accent. We use the unicode range for that.
  • The '{2,}' simply say a minimum of 2 char for the domain extension. You can replace this by '{2,63}' if you dont like the infinitive range.

Based on this article


$(document).ready(function() {_x000D_
var input = $('.input_field');_x000D_
var result = $('.test_result');_x000D_
        var regExpression = /\b[a-zA-Z0-9\u00C0-\u017F._%+-]+@[a-zA-Z0-9\u00C0-\u017F.-]+\.[a-zA-Z]{2,}\b/;_x000D_
          var isValid = regExpression.test(input.val());_x000D_
          if (isValid)_x000D_
              result.html('<span style="color:green;">This email is valid</span>');_x000D_
              result.html('<span style="color:red;">This email is not valid</span>');_x000D_
body {_x000D_
    padding: 40px;_x000D_
label {_x000D_
    font-weight: bold;_x000D_
input[type=text] {_x000D_
    width: 20em_x000D_
.test_result {_x000D_
<script src=""></script>_x000D_
<label for="search_field">Input</label>_x000D_
<input type='text' class='input_field' />_x000D_
<button type="button" class="btnTest">_x000D_
<div class="test_result">_x000D_
Not Tested_x000D_

Adding a directory to the PATH environment variable in Windows

  • Command line changes will not be permanent and will be lost when the console closes.
  • The path works like first comes first served.
  • You may want to override other already included executables. For instance, if you already have another version on your path and you want to add different version without making a permanent change on path, you should put the directory at the beginning of the command.

To override already included executables;

set PATH=C:\xampp\php;%PATH%;

percentage of two int?

Two options:

Do the division after the multiplication:

int n = 25;
int v = 100;
int percent = n * 100 / v;

Convert an int to a float before dividing

int n = 25;
int v = 100;
float percent = n * 100f / v;
//  float percent = (float) n * 100 / v;
//  float percent = n * 100 / (float) v;

How to extract the decision rules from scikit-learn decision-tree?

from StringIO import StringIO
out = StringIO()
out = tree.export_graphviz(clf, out_file=out)
print out.getvalue()

You can see a digraph Tree. Then, clf.tree_.feature and clf.tree_.value are array of nodes splitting feature and array of nodes values respectively. You can refer to more details from this github source.

How to set standard encoding in Visual Studio

The Problem is Windows and Microsoft applications put byte order marks at the beginning of all your files so other applications often break or don't read these UTF-8 encoding marks. I perfect example of this problem was triggering quirsksmode in old IE web browsers when encoding in UTF-8 as browsers often display web pages based on what encoding falls at the start of the page. It makes a mess when other applications view those UTF-8 Visual Studio pages.

I usually do not recommend Visual Studio Extensions, but I do this one to fix that issue:

Fix File Encoding:

The FixFileEncoding above install REMOVES the byte order mark and forces VS to save ALL FILES without signature in UTF-8. After installing go to Tools > Option then choose "FixFileEncoding". It should allow you to set all saves as UTF-8 . Add "cshtml to the list of files to always save in UTF-8 without the byte order mark as so: ".(htm|html|cshtml)$)".

Now open one of your files in Visual Studio. To verify its saving as UTF-8 go to File > Save As, then under the Save button choose "Save With Encoding". It should choose "UNICODE (Save without Signature)" by default from the list of encodings. Now when you save that page it should always save as UTF-8 without byte order mark at the beginning of the file when saving in Visual Studio.

How can we redirect a Java program console output to multiple files?

Go to run as and choose Run Configurations -> Common and in the Standard Input and Output you can choose a File also.

JSON and escaping characters

hmm, well here's a workaround anyway:

function JSON_stringify(s, emit_unicode)
   var json = JSON.stringify(s);
   return emit_unicode ? json : json.replace(/[\u007f-\uffff]/g,
      function(c) { 
        return '\\u'+('0000'+c.charCodeAt(0).toString(16)).slice(-4);

test case:

js>s='15\u00f8C 3\u0111';
15°C 3?
js>JSON_stringify(s, true)
"15°C 3?"
js>JSON_stringify(s, false)
"15\u00f8C 3\u0111"

Constructor overloading in Java - best practice

Constructor overloading is like method overloading. Constructors can be overloaded to create objects in different ways.

The compiler differentiates constructors based on how many arguments are present in the constructor and other parameters like the order in which the arguments are passed.

For further details about java constructor, please visit

Php, wait 5 seconds before executing an action



Convert varchar to uniqueidentifier in SQL Server

The guid provided is not correct format(.net Provided guid).

begin try
select convert(uniqueidentifier,'a89b1acd95016ae6b9c8aabb07da2010')
end try
begin catch
print '1'
end catch

Draw horizontal rule in React Native

Maybe you should try using react-native-hr something like this:

<Hr lineColor='#b3b3b3'/>


set serveroutput on in oracle procedure

To understand the use of "SET SERVEROUTPUT ON" I will take an example

a number(10)  :=10;
dbms_output.put_line(a) ;
dbms_output.put_line('Hello World ! ')  ;

With an output : PL/SQl procedure successfully completed i.e without the expected output

And the main reason behind is that ,whatever we pass inside dbms_output.put_line(' ARGUMENT '/VALUES) i.e. ARGUMENT/VALUES , is internally stored inside a buffer in SGA(Shared Global Area ) memory area upto 2000 bytes .

*NOTE :***However one should note that this buffer is only created when we use **dbms_output package. And we need to set the environment variable only once for a session !!

And in order to fetch it from that buffer we need to set the environment variable for the session . It makes a lot of confusion to the beginners that we are setting the server output on ( because of its nomenclature ) , but unfortunately its nothing like that . Using SET SERVER OUTPUT ON are just telling the PL/SQL engine that

*Hey please print the ARGUMENT/VALUES that I will be passing inside dbms_output.put_line
and in turn PL/SQl run time engine prints the argument on the main console .

I think I am clear to you all . Wish you all the best . To know more about it with the architectural structure of Oracle Server Engine you can see my answer on Quora

And to answer your question "One should use SET SERVER OUTPUT in the beginning of the session. "

How do I resolve "Cannot find module" error using Node.js?

Just found an unusual scenario that may be of use to someone and is sort of a red herring.

I was also getting the Cannot Find Module error but oddly everything worked perfectly in my local (Mac hosted) Node.js environment. This problem only appeared when the code was deployed on our Linux server.

Well... it turned out to be a typo that (apparently) the Mac based Node.js installation was perfectly happy to ignore.

The include looked like this:

var S3Uploader = require('./S3Uploader.class');

But the actual file was called "s3Uploader.class.js"

Notice the casing difference in the 's' vs. 'S' between the code and the filename.

So - in the odd chance that none of the other solutions here are solving your problem, triple check that you're not mis-casing the characters in your included filename! :)

and DUH!

Setting Camera Parameters in OpenCV/Python

I had the same problem with openCV on Raspberry Pi... don't know if this can solve your problem, but what worked for me was

import time
import cv2

cap = cv2.VideoCapture(0)




cap.set(15, -8.0)

the time you have to use can be different

How to calculate Average Waiting Time and average Turn-around time in SJF Scheduling?

Gantt chart is wrong... First process P3 has arrived so it will execute first. Since the burst time of P3 is 3sec after the completion of P3, processes P2,P4, and P5 has been arrived. Among P2,P4, and P5 the shortest burst time is 1sec for P2, so P2 will execute next. Then P4 and P5. At last P1 will be executed.

Gantt chart for this ques will be:

| P3 | P2 | P4 | P5 | P1 |

1    4    5    7   11   14

Average waiting time=(0+2+2+3+3)/5=2

Average Turnaround time=(3+3+4+7+6)/5=4.6

Difference between InvariantCulture and Ordinal string comparison

Always try to use InvariantCulture in those string methods that accept it as overload. By using InvariantCulture you are on a safe side. Many .NET programmers may not use this functionality but if your software will be used by different cultures, InvariantCulture is an extremely handy feature.

Error when testing on iOS simulator: Couldn't register with the bootstrap server

Resetting the iOS Simulator fixed the error for me. Although this will remove all of the Apps you have in Simulator, it fixes the problem without having to restart the machine.

You can reset your iOS Simulator by doing the following:

1) Go to the "iOS Simulator" menu, next to the Apple (?) logo on the far left of your main screen.
2) Select "Reset Content and Settings...".
3) Read the pop message and if you agree click "Reset" otherwise, click "Don't Reset".

How to Access Hive via Python?

This can be a quick hack to connect hive and python,

from pyhive import hive
cursor = hive.connect('YOUR_HOST_NAME').cursor()
cursor.execute('SELECT * from table_name LIMIT 5',async=True)
print cursor.fetchall()

Output: List of Tuples

Can you do greater than comparison on a date in a Rails 3 search?

You can try to use:

where(date: p[:date]..Float::INFINITY)

equivalent in sql

WHERE (`date` >= p[:date])

The result is:

Note.where(user_id:, notetype: p[:note_type], date: p[:date]..Float::INFINITY).order(:fecha, :created_at)

And I have changed too

order('date ASC, created_at ASC')


order(:fecha, :created_at)

Why should C++ programmers minimize use of 'new'?

Two reasons:

  1. It's unnecessary in this case. You're making your code needlessly more complicated.
  2. It allocates space on the heap, and it means that you have to remember to delete it later, or it will cause a memory leak.

How do I grab an INI value within a shell script?

For people (like me) looking to read INI files from shell scripts (read shell, not bash) - I've knocked up the a little helper library which tries to do exactly that: (MIT license, do with it as you please. I've linked above including it inline as the code is quite lengthy.)

It's somewhat more "complicated" than the simple sed lines suggested above - but works on a very similar basis.

Function reads in a file line-by-line - looking for section markers ([section]) and key/value declarations (key=value).

Ultimately you get a callback to your own function - section, key and value.

When should I use git pull --rebase?

I would like to provide a different perspective on what "git pull --rebase" actually means, because it seems to get lost sometimes.

If you've ever used Subversion (or CVS), you may be used to the behavior of "svn update". If you have changes to commit and the commit fails because changes have been made upstream, you "svn update". Subversion proceeds by merging upstream changes with yours, potentially resulting in conflicts.

What Subversion just did, was essentially "pull --rebase". The act of re-formulating your local changes to be relative to the newer version is the "rebasing" part of it. If you had done "svn diff" prior to the failed commit attempt, and compare the resulting diff with the output of "svn diff" afterwards, the difference between the two diffs is what the rebasing operation did.

The major difference between Git and Subversion in this case is that in Subversion, "your" changes only exist as non-committed changes in your working copy, while in Git you have actual commits locally. In other words, in Git you have forked the history; your history and the upstream history has diverged, but you have a common ancestor.

In my opinion, in the normal case of having your local branch simply reflecting the upstream branch and doing continuous development on it, the right thing to do is always "--rebase", because that is what you are semantically actually doing. You and others are hacking away at the intended linear history of a branch. The fact that someone else happened to push slightly prior to your attempted push is irrelevant, and it seems counter-productive for each such accident of timing to result in merges in the history.

If you actually feel the need for something to be a branch for whatever reason, that is a different concern in my opinion. But unless you have a specific and active desire to represent your changes in the form of a merge, the default behavior should, in my opinion, be "git pull --rebase".

Please consider other people that need to observe and understand the history of your project. Do you want the history littered with hundreds of merges all over the place, or do you want only the select few merges that represent real merges of intentional divergent development efforts?

Install specific branch from github using Npm

Tried suggested answers, but got it working only with this prefix approach:

npm i github:user/repo.git#version --save -D

How to close a web page on a button click, a hyperlink or a link button click?

To close a windows form (System.Windows.Forms.Form) when one of its button is clicked: in Visual Studio, open the form in the designer, right click on the button and open its property page, then select the field DialogResult an set it to OK or the appropriate value.

How to schedule a function to run every hour on Flask?

You can use BackgroundScheduler() from APScheduler package (v3.5.3):

import time
import atexit

from apscheduler.schedulers.background import BackgroundScheduler

def print_date_time():
    print(time.strftime("%A, %d. %B %Y %I:%M:%S %p"))

scheduler = BackgroundScheduler()
scheduler.add_job(func=print_date_time, trigger="interval", seconds=3)

# Shut down the scheduler when exiting the app
atexit.register(lambda: scheduler.shutdown())

Note that two of these schedulers will be launched when Flask is in debug mode. For more information, check out this question.

Why does ENOENT mean "No such file or directory"?

It's an abbreviation of Error NO ENTry (or Error NO ENTity), and can actually be used for more than files/directories.

It's abbreviated because C compilers at the dawn of time didn't support more than 8 characters in symbols.

Download file of any type in Asp.Net MVC using FileResult?

If you're using .NET Framework 4.5 then you use use the MimeMapping.GetMimeMapping(string FileName) to get the MIME-Type for your file. This is how I've used it in my action.

return File(Path.Combine(@"c:\path", fileFromDB.FileNameOnDisk), MimeMapping.GetMimeMapping(fileFromDB.FileName), fileFromDB.FileName);

Django: Redirect to previous page after login

You can also do this

<input type="hidden" name="text" value="{% url 'dashboard' %}" />

How do you implement a circular buffer in C?

C style, simple ring buffer for integers. First use init than use put and get. If buffer does not contain any data it returns "0" zero.

// ring buffer address based
#define cRingBufCount   512
int     sRingBuf[cRingBufCount];    // Ring Buffer
int     sRingBufPut;                // Input index address
int     sRingBufGet;                // Output index address
Bool    sRingOverWrite;

void    GetRingBufCount(void)
int     r;
`       r= sRingBufPut - sRingBufGet;
        if ( r < cRingBufCount ) r+= cRingBufCount;
        return r; 

void    InitRingBuffer(void)
        sRingBufPut= 0;
        sRingBufGet= 0;

void    PutRingBuffer(int d)
        sRingBuffer[sRingBufPut]= d;
        if (sRingBufPut==sRingBufGet)// both address are like ziro
            sRingBufPut= IncRingBufferPointer(sRingBufPut);
            sRingBufGet= IncRingBufferPointer(sRingBufGet);
        else //Put over write a data
            sRingBufPut= IncRingBufferPointer(sRingBufPut);
            if (sRingBufPut==sRingBufGet)
                sRingOverWrite= Ture;
                sRingBufGet= IncRingBufferPointer(sRingBufGet);

int     GetRingBuffer(void)
int     r;
        if (sRingBufGet==sRingBufPut) return 0;
        r= sRingBuf[sRingBufGet];
        sRingBufGet= IncRingBufferPointer(sRingBufGet);
        return r;

int     IncRingBufferPointer(int a)
        a+= 1;
        if (a>= cRingBufCount) a= 0;
        return a;

how to convert an RGB image to numpy array?

load the image by using following syntax:-

from keras.preprocessing import image

X_test=image.load_img('four.png',target_size=(28,28),color_mode="grayscale"); #loading image and then convert it into grayscale and with it's target size 
X_test=image.img_to_array(X_test); #convert image into array

Angular2: How to load data before rendering the component?

You can pre-fetch your data by using Resolvers in Angular2+, Resolvers process your data before your Component fully be loaded.

There are many cases that you want to load your component only if there is certain thing happening, for example navigate to Dashboard only if the person already logged in, in this case Resolvers are so handy.

Look at the simple diagram I created for you for one of the way you can use the resolver to send the data to your component.

enter image description here

Applying Resolver to your code is pretty simple, I created the snippets for you to see how the Resolver can be created:

import { Injectable } from '@angular/core';
import { Router, Resolve, RouterStateSnapshot, ActivatedRouteSnapshot } from '@angular/router';
import { MyData, MyService } from './my.service';

export class MyResolver implements Resolve<MyData> {
  constructor(private ms: MyService, private router: Router) {}

  resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Promise<MyData> {
    let id = route.params['id'];

    return => {
      if (data) {
        return data;
      } else {

and in the module:

import { MyResolver } from './my-resolver.service';

  imports: [
  exports: [
  providers: [
export class MyModule { }

and you can access it in your Component like this:

 ngOnInit() {
      .subscribe((data: { mydata: myData }) => { =;

And in the Route something like this (usually in the app.routing.ts file):

{path: 'yourpath/:id', component: YourComponent, resolve: { myData: MyResolver}}

How to check if Thread finished execution

You could fire an event from your thread when it finishes and subscribe to that.

Alternatively you can call Thread.Join() without any arguments:

Blocks the calling thread until a thread terminates, while continuing to perform standard COM and SendMessage pumping.

Thread.Join(1) will:

Blocks the calling thread until a thread terminates or the specified time elapses, while continuing to perform standard COM and SendMessage pumping.

In this case the specified time is 1 millisecond.

Secure random token in Node.js

Try crypto.randomBytes():

require('crypto').randomBytes(48, function(err, buffer) {
  var token = buffer.toString('hex');

The 'hex' encoding works in node v0.6.x or newer.

.gitignore after commit

No you cannot force a file that is already committed in the repo to be removed just because it is added to the .gitignore

You have to git rm --cached to remove the files that you don't want in the repo. ( --cached since you probably want to keep the local copy but remove from the repo. ) So if you want to remove all the exe's from your repo do

git rm --cached /\*.exe

(Note that the asterisk * is quoted from the shell - this lets git, and not the shell, expand the pathnames of files and subdirectories)

Android Linear Layout - How to Keep Element At Bottom Of View?

Step 1 : Create two view inside a linear layout

Step 2 : First view must set to android:layout_weight="1"

Step 3 : Second view will automatically putted downwards

android:orientation="vertical" >

    android:layout_weight="1" />



How to debug Javascript with IE 8

This won't help you step through code or break on errors, but it's a useful way to get the same debug console for your project on all browsers.

myLog = function() {
    if (!myLog._div) { myLog.createDiv(); }

    var logEntry = document.createElement('span');
    for (var i=0; i < arguments.length; i++) {
        logEntry.innerHTML += myLog.toJson(arguments[i]) + '<br />';
    logEntry.innerHTML += '<br />';

myLog.createDiv = function() {
    myLog._div = document.body.appendChild(document.createElement('div'));
    var props = {
        position:'absolute', top:'10px', right:'10px', background:'#333', border:'5px solid #333', 
        color: 'white', width: '400px', height: '300px', overflow: 'auto', fontFamily: 'courier new',
        fontSize: '11px', whiteSpace: 'nowrap'
    for (var key in props) {[key] = props[key]; }
myLog.toJSON = function(obj) {
    if (typeof window.uneval == 'function') { return uneval(obj); }
    if (typeof obj == 'object') {
        if (!obj) { return 'null'; }
        var list = [];
        if (obj instanceof Array) {
            for (var i=0;i < obj.length;i++) { list.push(this.toJson(obj[i])); }
            return '[' + list.join(',') + ']';
        } else {
            for (var prop in obj) { list.push('"' + prop + '":' + this.toJson(obj[prop])); }
            return '{' + list.join(',') + '}';
    } else if (typeof obj == 'string') {
        return '"' + obj.replace(/(["'])/g, '\\$1') + '"';
    } else {
        return new String(obj);

myLog('log statement');
myLog('logging an object', { name: 'Marcus', likes: 'js' });

This is put together pretty hastily and is a bit sloppy, but it's useful nonetheless and can be improved easily!

CSS ''background-color" attribute not working on checkbox inside <div>

When you input the body tag, press space just one time without closing the tag and input bgcolor="red", just for instance. Then choose a diff color for your font.

Can I find events bound on an element with jQuery?

While this isn't exactly specific to jQuery selectors/objects, in FireFox Quantum 58.x, you can find event handlers on an element using the Dev tools:

  1. Right-click the element
  2. In the context menu, Click 'Inspect Element'
  3. If there is an 'ev' icon next to the element (yellow box), click on 'ev' icon
  4. Displays all events for that element and event handler

FF Quantum Dev Tools

Insert node at a certain position in a linked list C++

Node* InsertNth(int data, int position)
  struct Node *n=new struct Node;
  {// this will also cover insertion at head (if there is no problem with the input)


      struct Node *c=new struct Node;
      int count=1;

    return ;

Eclipse: Frustration with Java 1.7 (unbound library)

Have you actually downloaded and installed one of the milestone builds from ?

You can have a play with the features, though it's not stable so you shouldn't be releasing software against them.

How can I refresh or reload the JFrame?



If it still doesn't work then after completing the above step try


Get file name from a file location in Java

new File(fileName).getName();


int idx = fileName.replaceAll("\\\\", "/").lastIndexOf("/");
return idx >= 0 ? fileName.substring(idx + 1) : fileName;

Notice that the first solution is system dependent. It only takes the system's path separator character into account. So if your code runs on a Unix system and receives a Windows path, it won't work. This is the case when processing file uploads being sent by Internet Explorer.

How to serve all existing static files directly with NGINX, but proxy the rest to a backend server.

Try this:

location / {
    root /path/to/root;
    expires 30d;
    access_log off;

location ~* ^.*\.php$ {
    if (!-f $request_filename) {
        return 404;
    proxy_set_header X-Real-IP  $remote_addr;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

Hopefully it works. Regular expressions have higher priority than plain strings, so all requests ending in .php should be forwared to Apache if only a corresponding .php file exists. Rest will be handled as static files. The actual algorithm of evaluating location is here.

XSLT equivalent for JSON

JSONiq is such a standard and Zorba an open-source C++ implementation. JSONiq can also be seen as XQuery with adding JSON as a native data type.

Change link color of the current page with CSS

include this! on your page where you want to change the colors save as .php

<?php include("includes/navbar.php"); ?>

then add a new file in an includes folder.


<div <?php //Using REQUEST_URI

$currentpage = $_SERVER['REQUEST_URI'];

if(preg_match("/index/i", $currentpage)||($currentpage=="/"))
    echo " class=\"navbarorange/*the css class for your nav div*/\" ";
elseif(preg_match("/about/*or second page name*//i", $currentpage))
    echo " class=\"navbarpink\" ";
elseif(preg_match("/contact/* or edit 3rd page name*//i", $currentpage))
    echo " class=\"navbargreen\" ";?> >

Right query to get the current number of connections in a PostgreSQL DB

From looking at the source code, it seems like the pg_stat_database query gives you the number of connections to the current database for all users. On the other hand, the pg_stat_activity query gives the number of connections to the current database for the querying user only.

How do I use Wget to download all images into a single folder, from a URL?

According to the man page the -P flag is:

-P prefix --directory-prefix=prefix Set directory prefix to prefix. The directory prefix is the directory where all other files and subdirectories will be saved to, i.e. the top of the retrieval tree. The default is . (the current directory).

This mean that it only specifies the destination but where to save the directory tree. It does not flatten the tree into just one directory. As mentioned before the -nd flag actually does that.

@Jon in the future it would be beneficial to describe what the flag does so we understand how something works.

Shell script not running, command not found


chmod 777 ./



Or, add your program to a directory recognized in your $PATH variable. Example: Path Variable Example Which will then allow you to call your program without ./

How to use opencv in using Gradle?

These are the steps necessary to use OpenCV with Android Studio 1.2:

  • Download OpenCV and extract the archive
  • Open your app project in Android Studio
  • Go to File -> New -> Import Module...
  • Select sdk/java in the directory you extracted before
  • Set Module name to opencv
  • Press Next then Finish
  • Open build.gradle under imported OpenCV module and update compileSdkVersion and buildToolsVersion to versions you have on your machine
  • Add compile project(':opencv') to your app build.gradle

    dependencies {
        compile project(':opencv')
  • Press Sync Project with Gradle Files

Socket send and receive byte array

You need to either have the message be a fixed size, or you need to send the size or you need to use some separator characters.

This is the easiest case for a known size (100 bytes):

in = new DataInputStream(server.getInputStream());
byte[] message = new byte[100]; // the well known size

In this case DataInputStream makes sense as it offers readFully(). If you don't use it, you need to loop yourself until the expected number of bytes is read.

yum error "Cannot retrieve metalink for repository: epel. Please verify its path and try again" updating ContextBroker

I solved this issue editing both /etc/yum.repos.d/epel.repo and /etc/yum.repos.d/epel-testing.repo files, commenting all entries starting with mirrorlist=... and uncommenting all the entries starting with baseurl=....

Python to open Chrome browser

In the case of Windows, the path uses a UNIX-style path, so make the backslash into forward slashes.

webbrowser.get("C:/Program Files (x86)/Google/Chrome/Application/chrome.exe %s").open("")

See: Python: generic webbrowser.get().open() for chrome.exe does not work

Delete all duplicate rows Excel vba

The duplicate values in any column can be deleted with a simple for loop.

Sub remove()
Dim a As Long
For a = Cells(Rows.Count, 1).End(xlUp).Row To 1 Step -1
If WorksheetFunction.CountIf(Range("A1:A" & a), Cells(a, 1)) > 1 Then Rows(a).Delete
End Sub

C++ [Error] no matching function for call to

to add to John's answer:

what you want to pass to the shuffle function is a deck of cards from the class deckOfCards that you've declared in main; however, the deck of cards or vector<Card> deck that you've declared in your class is private, so not accessible from outside the class. this means you'd want a getter function, something like this:

class deckOfCards
        vector<Card> deck;

        static int count;
        static int next;
        void shuffle(vector<Card>& deck);
        Card dealCard();
        bool moreCards();
        vector<Card>& getDeck() {   //GETTER
            return deck;

this will in turn allow you to call your shuffle function from main like this:

deckOfCards cardDeck; // create DeckOfCards object
cardDeck.shuffle(cardDeck.getDeck()); // shuffle the cards in the deck

however, you have more problems, specifically when calling cout. first, you're calling the dealCard function wrongly; as dealCard is a memeber function of a class, you should be calling it like this cardDeck.dealCard(); instead of this dealCard(cardDeck);.

now, we come to your second problem - print to standard output. you're trying to print your deal card, which is an object of type Card by using the following instruction:

cout << cardDeck.dealCard();// deal the cards in the deck

yet, the cout doesn't know how to print it, as it's not a standard type. this means you should overload your << operator to print whatever you want it to print when calling with a Card type.

How to compare two Dates without the time portion?

If you really want to use the java.util.Date, you would do something like this:

public class TimeIgnoringComparator implements Comparator<Date> {
  public int compare(Date d1, Date d2) {
    if (d1.getYear() != d2.getYear()) 
        return d1.getYear() - d2.getYear();
    if (d1.getMonth() != d2.getMonth()) 
        return d1.getMonth() - d2.getMonth();
    return d1.getDate() - d2.getDate();

or, using a Calendar instead (preferred, since getYear() and such are deprecated)

public class TimeIgnoringComparator implements Comparator<Calendar> {
  public int compare(Calendar c1, Calendar c2) {
    if (c1.get(Calendar.YEAR) != c2.get(Calendar.YEAR)) 
        return c1.get(Calendar.YEAR) - c2.get(Calendar.YEAR);
    if (c1.get(Calendar.MONTH) != c2.get(Calendar.MONTH)) 
        return c1.get(Calendar.MONTH) - c2.get(Calendar.MONTH);
    return c1.get(Calendar.DAY_OF_MONTH) - c2.get(Calendar.DAY_OF_MONTH);

How do I UPDATE from a SELECT in SQL Server?

I add this only so you can see a quick way to write it so that you can check what will be updated before doing the update.

SET  Table.col1 = other_table.col1,
     Table.col2 = other_table.col2 
--select Table.col1, other_table.col,Table.col2,other_table.col2, *   
FROM     Table 
INNER JOIN     other_table 
    ON = 

How to change value of process.env.PORT in node.js?

EDIT: Per @sshow's comment, if you're trying to run your node app on port 80, the below is not the best way to do it. Here's a better answer: How do I run Node.js on port 80?

Original Answer:

If you want to do this to run on port 80 (or want to set the env variable more permanently),

  1. Open up your bash profile vim ~/.bash_profile
  2. Add the environment variable to the file export PORT=80
  3. Open up the sudoers config file sudo visudo
  4. Add the following line to the file exactly as so Defaults env_keep +="PORT"

Now when you run sudo node app.js it should work as desired.

Naming Classes - How to avoid calling everything a "<WhatEver>Manager"?

Specific to C#, I found "Framework Design Guidelines: Conventions, Idioms, and Patterns for Reusable .NET Libraries" to have lots of good information on the logic of naming.

As far as finding those more specific words though, I often use a thesaurus and jump through related words to try and find a good one. I try not to spend to much time with it though, as I progress through development I come up with better names, or sometimes realize that SuchAndSuchManager should really be broken up into multiple classes, and then the name of that deprecated class becomes a non-issue.

How do I reverse an int array in Java?

static int[] reverseArray(int[] a) {
     int ret[] = new int[a.length];
     for(int i=0, j=a.length-1; i<a.length && j>=0; i++, j--)
         ret[i] = a[j];
     return ret;

How do I install opencv using pip?

As a reference it might help someone... On Debian system I hard to do the following:

apt-get install -y libsm6 libxext6 libxrender-dev
pip3 install opencv-python
python3 -c "import cv2"

What EXACTLY is meant by "de-referencing a NULL pointer"?

From wiki

A null pointer has a reserved value, often but not necessarily the value zero, indicating that it refers to no object

Since a null-valued pointer does not refer to a meaningful object, an attempt to dereference a null pointer usually causes a run-time error.

int val =1;
int *p = NULL;
*p = val; // Whooosh!!!! 

How can I easily convert DataReader to List<T>?

Obviously @Ian Ringrose's central thesis that you should be using a library for this is the best single answer here (hence a +1), but for minimal throwaway or demo code here's a concrete illustration of @SLaks's subtle comment on @Jon Skeet's more granular (+1'd) answer:

public List<XXX> Load( <<args>> )
    using ( var connection = CreateConnection() )
    using ( var command = Create<<ListXXX>>Command( <<args>>, connection ) )
        using ( var reader = command.ExecuteReader() )
            return reader.Cast<IDataRecord>()
                .Select( x => new XXX( x.GetString( 0 ), x.GetString( 1 ) ) )

As in @Jon Skeet's answer, the

            .Select( x => new XXX( x.GetString( 0 ), x.GetString( 1 ) ) )

bit can be extracted into a helper (I like to dump them in the query class):

    public static XXX FromDataRecord( this IDataRecord record)
        return new XXX( record.GetString( 0 ), record.GetString( 1 ) );

and used as:

            .Select( FromDataRecord )

UPDATE Mar 9 13: See also Some excellent further subtle coding techniques to split out the boilerplate in this answer

Kotlin - How to correctly concatenate a String

Try this, I think this is a natively way to concatenate strings in Kotlin:

val result = buildString{


// you will see "ab" in console.

What is the difference between single and double quotes in SQL?

I use this mnemonic:

  • Single quotes are for strings (one thing)
  • Double quotes are for tables names and column names (two things)

This is not 100% correct according to the specs, but this mnemonic helps me (human being).

Converting an int or String to a char array on Arduino

None of that stuff worked. Here's a much simpler way .. the label str is the pointer to what IS an array...

String str = String(yourNumber, DEC); // Obviously .. get your int or byte into the string

str = str + '\r' + '\n'; // Add the required carriage return, optional line feed

byte str_len = str.length();

// Get the length of the whole lot .. C will kindly
// place a null at the end of the string which makes
// it by default an array[].
// The [0] element is the highest digit... so we
// have a separate place counter for the array...

byte arrayPointer = 0;

while (str_len)
    // I was outputting the digits to the TX buffer

    if ((UCSR0A & (1<<UDRE0))) // Is the TX buffer empty?
        UDR0 = str[arrayPointer];

time delayed redirect?

Include this code somewhere when you slide to your 'section' called blog.

$("#myLink").click(function() {
    setTimeout(function() {
        window.navigate("the url of the page you want to navigate back to");
    }, 2000);

Where myLink is the id of your href.

Getting data from selected datagridview row and which event?

You should check your designer file. Open Form1.Designer.cs and
find this line: windows Form Designer Generated Code.
Expand this and you will see a lot of code. So check Whether this line is there inside datagridview1 controls if not place it.

this.dataGridView1.CellClick += new System.Windows.Forms.DataGridViewCellEventHandler(this.dataGridView1_CellClick); 

I hope it helps.

Send auto email programmatically

It might be an easiest way-

    String recipientList = mEditTextTo.getText().toString();
    String[] recipients = recipientList.split(",");

    String subject = mEditTextSubject.getText().toString();
    String message = mEditTextMessage.getText().toString();

    Intent intent = new Intent(Intent.ACTION_SEND);
    intent.putExtra(Intent.EXTRA_EMAIL, recipients);
    intent.putExtra(Intent.EXTRA_SUBJECT, subject);
    intent.putExtra(Intent.EXTRA_TEXT, message);

    startActivity(Intent.createChooser(intent, "Choose an email client"));

List of Java processes

The following commands will return only Java ProcessIDs. These commands are very useful especially whenever you want to feed another process by these return values (java PIDs).

sudo netstat -nlpt | awk '/java/ {print $7}' | tr '/java' ' '

sudo netstat -nlpt | awk '/java/ {print $7}' | sed 's/\/java/ /g'

But if you remove the latest pipe, you will be noticed these are java process

sudo netstat -nlpt | awk '/java/ {print $7}'

sudo netstat -nlpt | awk '/java/ {print $7}'

How to parse a string in JavaScript?

Use split on string:

var array = coolVar.split(/-/);

Getting Spring Application Context

Take a look at ContextSingletonBeanFactoryLocator. It provides static accessors to get hold of Spring's contexts, assuming they have been registered in certain ways.

It's not pretty, and more complex than perhaps you'd like, but it works.

Superscript in markdown (Github flavored)?

Use the <sup></sup>tag (<sub></sub> is the equivalent for subscripts). See this gist for an example.

Define a fixed-size list in Java

A Java list is a collection of objects ... the elements of a list. The size of the list is the number of elements in that list. If you want that size to be fixed, that means that you cannot either add or remove elements, because adding or removing elements would violate your "fixed size" constraint.

The simplest way to implement a "fixed sized" list (if that is really what you want!) is to put the elements into an array and then Arrays.asList(array) to create the list wrapper. The wrapper will allow you to do operations like get and set, but the add and remove operations will throw exceptions.

And if you want to create a fixed-sized wrapper for an existing list, then you could use the Apache commons FixedSizeList class. But note that this wrapper can't stop something else changing the size of the original list, and if that happens the wrapped list will presumably reflect those changes.

On the other hand, if you really want a list type with a fixed limit (or limits) on its size, then you'll need to create your own List class to implement this. For example, you could create a wrapper class that implements the relevant checks in the various add / addAll and remove / removeAll / retainAll operations. (And in the iterator remove methods if they are supported.)

So why doesn't the Java Collections framework implement these? Here's why I think so:

  1. Use-cases that need this are rare.
  2. The use-cases where this is needed, there are different requirements on what to do when an operation tries to break the limits; e.g. throw exception, ignore operation, discard some other element to make space.
  3. A list implementation with limits could be problematic for helper methods; e.g. Collections.sort.

C# - using List<T>.Find() with custom objects

        // Find a book by its ID.
        Book result = Books.Find(
        delegate(Book bk)
            return bk.ID == IDtoFind;
        if (result != null)
            DisplayResult(result, "Find by ID: " + IDtoFind);   
            Console.WriteLine("\nNot found: {0}", IDtoFind);

How to Set a Custom Font in the ActionBar Title?

You can do this using a custom TypefaceSpan class. It's superior to the customView approach indicated above because it doesn't break when using other Action Bar elements like expanding action views.

The use of such a class would look something like this:

SpannableString s = new SpannableString("My Title");
s.setSpan(new TypefaceSpan(this, "MyTypeface.otf"), 0, s.length(),

// Update the action bar title with the TypefaceSpan instance
ActionBar actionBar = getActionBar();

The custom TypefaceSpan class is passed your Activity context and the name of a typeface in your assets/fonts directory. It loads the file and caches a new Typeface instance in memory. The complete implementation of TypefaceSpan is surprisingly simple:

 * Style a {@link Spannable} with a custom {@link Typeface}.
 * @author Tristan Waddington
public class TypefaceSpan extends MetricAffectingSpan {
      /** An <code>LruCache</code> for previously loaded typefaces. */
    private static LruCache<String, Typeface> sTypefaceCache =
            new LruCache<String, Typeface>(12);

    private Typeface mTypeface;

     * Load the {@link Typeface} and apply to a {@link Spannable}.
    public TypefaceSpan(Context context, String typefaceName) {
        mTypeface = sTypefaceCache.get(typefaceName);

        if (mTypeface == null) {
            mTypeface = Typeface.createFromAsset(context.getApplicationContext()
                    .getAssets(), String.format("fonts/%s", typefaceName));

            // Cache the loaded Typeface
            sTypefaceCache.put(typefaceName, mTypeface);

    public void updateMeasureState(TextPaint p) {

        // Note: This flag is required for proper typeface rendering
        p.setFlags(p.getFlags() | Paint.SUBPIXEL_TEXT_FLAG);

    public void updateDrawState(TextPaint tp) {

        // Note: This flag is required for proper typeface rendering
        tp.setFlags(tp.getFlags() | Paint.SUBPIXEL_TEXT_FLAG);

Simply copy the above class into your project and implement it in your activity's onCreate method as shown above.

Select records from today, this week, this month php mysql

Nathan's answer is very close however it will return a floating result set. As the time shifts, records will float off of and onto the result set. Using the DATE() function on NOW() will strip the time element from the date creating a static result set. Since the date() function is applied to now() instead of the actual date column performance should be higher since applying a function such as date() to a date column inhibits MySql's ability to use an index.

To keep the result set static use:




Execute a shell script in current shell with sudo permission

Even the first answer is absolutely brilliant, you probably want to only run script under sudo.

You have to specify the absolute path like:

sudo /home/user/
sudo ~/

(both are working)


sudo /bin/sh

It will always return

sudo: bin/sh: command not found
sudo: command not found

Problems after upgrading to Xcode 10: Build input file cannot be found

If you tried profiling, and then it didn't work, and now you cannot build, go into your Target pane (via the Project Icon), Switch to the Build Settings tab, search for PROFILE - and set CLANG_USE_OPTIMIZATION_PROFILE to "No".

Convert MySQL to SQlite

I found the perfect solution

First, you need this script (put it into a file called ''):

if [ "x$1" == "x" ]; then
  echo "Usage: $0 <dumpname>"

cat $1 |
grep -v ' KEY "' |
grep -v ' UNIQUE KEY "' |
grep -v ' PRIMARY KEY ' |
sed '/^SET/d' |
sed 's/ unsigned / /g' |
sed 's/ auto_increment/ primary key autoincrement/g' |
sed 's/ smallint([0-9]*) / integer /g' |
sed 's/ tinyint([0-9]*) / integer /g' |
sed 's/ int([0-9]*) / integer /g' |
sed 's/ character set [^ ]* / /g' |
sed 's/ enum([^)]*) / varchar(255) /g' |
sed 's/ on update [^,]*//g' |
sed 's/\\r\\n/\\n/g' |
sed 's/\\"/"/g' |
perl -e 'local $/;$_=<>;s/,\n\)/\n\)/gs;print "begin;\n";print;print "commit;\n"' |
perl -pe '
if (/^(INSERT.+?)\(/) {
' > $1.sql
cat $1.sql | sqlite3 $1.db > $1.err
ERRORS=`cat $1.err | wc -l`
if [ $ERRORS == 0 ]; then
  echo "Conversion completed without error. Output file: $1.db"
  rm $1.sql
  rm $1.err
  echo "There were errors during conversion.  Please review $1.err and $1.sql for details."

Then, dump a copy of your database:

you@prompt:~$ mysqldump -u root -p --compatible=ansi --skip-opt generator > dumpfile

And now, run the conversion:

you@prompt:~$ dumpfile

And if all goes well, you should now have a dumpfile.db which can be used via sqlite3.

you@prompt:~$ sqlite3 dumpfile.db 
SQLite version 3.6.10
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .tables
dg_cities                 dg_forms                  dg_surnames             
dg_counties               dg_provinces              dg_user_accounts        
dg_countries              dg_provinces_netherlands
dg_first_names            dg_states

Collision resolution in Java HashMap

Your case is not talking about collision resolution, it is simply replacement of older value with a new value for the same key because Java's HashMap can't contain duplicates (i.e., multiple values) for the same key.

In your example, the value 17 will be simply replaced with 20 for the same key 10 inside the HashMap.

If you are trying to put a different/new value for the same key, it is not the concept of collision resolution, rather it is simply replacing the old value with a new value for the same key. It is how HashMap has been designed and you can have a look at the below API (emphasis is mine) taken from here.

public V put(K key, V value)

Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced.

On the other hand, collision resolution techniques comes into play only when multiple keys end up with the same hashcode (i.e., they fall in the same bucket location) where an entry is already stored. HashMap handles the collision resolution by using the concept of chaining i.e., it stores the values in a linked list (or a balanced tree since Java8, depends on the number of entries).

What USB driver should we use for the Nexus 5?

Everything else here failed for me initially (it kept coming up as an MTP device no matter how many times I uninstalled and restarted).

However, by going and enabling USB debugging, it worked. Just do this:

  1. Uninstall the Nexus 5 driver
  2. Disconnect from the computer
  3. Enable developer options, see How to Enable Developer Options on the Nexus 5 & KitKat.
  4. Enable USB debugging: Go to Settings -> Developer Options -> USB Debugging
  5. Reconnect
  6. It will probably fail to install all drivers. Go update the drivers as described in other answers.

How to update npm

Looks like you are using Ubuntu (from the command line you show). To update npm and nodejs you can use the PPA repository:

sudo add-apt-repository ppa:chris-lea/node.js
sudo apt-get update
sudo apt-get install nodejs npm

How to restore the dump into your running mongodb

For mongoDB database restore use this command here

mongorestore --db databasename --drop dump file path

Git Stash vs Shelve in IntelliJ IDEA

I would prefer to shelve changes instead of stashing them if I am not sharing my changes elsewhere.

Stashing is a git feature and doesn't give you the option to select specific files or changes inside a file. Shelving can do that but this is an IDE-specific feature, not a git feature:

enter image description here

As you can see I am able to choose to specify which files/lines to include on my shelve. Note that I can't do that with stashing.

Beware using shelves in the IDE may limit the portability of your patches because those changes are not stored in a .git folder.

Some helpful links:

How to get value by key from JObject?

You can also get the value of an item in the jObject like this:

JToken value;
if (json.TryGetValue(key, out value))

rebase in progress. Cannot commit. How to proceed or stop (abort)?

I got into this state recently. After resolving conflicts during a rebase, I committed my changes, rather than running git rebase --continue. This yields the same messages you saw when you ran your git status and git rebase --continue commands. I resolved the issue by running git rebase --abort, and then re-running the rebase. One could likely also skip the rebase, but I wasn't sure what state that would leave me in.

$ git rebase --continue
Applying: <commit message>
No changes - did you forget to use 'git add'?
If there is nothing left to stage, chances are that something else
already introduced the same changes; you might want to skip this patch.

When you have resolved this problem, run "git rebase --continue".
If you prefer to skip this patch, run "git rebase --skip" instead.
To check out the original branch and stop rebasing, run "git rebase --abort".

$ git status
rebase in progress; onto 4df0775
You are currently rebasing branch '<local-branch-name>' on '4df0775'.
  (all conflicts fixed: run "git rebase --continue")

nothing to commit, working directory clean

How do I exit the Vim editor?

If you want to quit without saving in Vim and have Vim return a non-zero exit code, you can use :cq.

I use this all the time because I can't be bothered to pinky shift for !. I often pipe things to Vim which don't need to be saved in a file. We also have an odd SVN wrapper at work which must be exited with a non-zero value in order to abort a checkin.

Replace non-ASCII characters with a single space

If the replacement character can be '?' instead of a space, then I'd suggest result = text.encode('ascii', 'replace').decode():

"""Test the performance of different non-ASCII replacement methods."""

import re
from timeit import timeit

# 10_000 is typical in the project that I'm working on and most of the text
# is going to be non-ASCII.
text = 'Æ' * 10_000

result = ''.join([c if ord(c) < 128 else '?' for c in text])

result = text.encode('ascii', 'replace').decode()



How to hide Table Row Overflow?

Only downside (it seems), is that the table cell widths are identical. Any way to get around this? – Josh Stodola Oct 12 at 15:53

Just define width of the table and width for each table cell

something like

table {border-collapse:collapse; table-layout:fixed; width:900px;}
th {background: yellow; }
td {overflow:hidden;white-space:nowrap; }

It works like a charm :o)

Execution order of events when pressing PrimeFaces p:commandButton

It failed because you used ajax="false". This fires a full synchronous request which in turn causes a full page reload, causing the oncomplete to be never fired (note that all other ajax-related attributes like process, onstart, onsuccess, onerror and update are also never fired).

That it worked when you removed actionListener is also impossible. It should have failed the same way. Perhaps you also removed ajax="false" along it without actually understanding what you were doing. Removing ajax="false" should indeed achieve the desired requirement.

Also is it possible to execute actionlistener and oncomplete simultaneously?

No. The script can only be fired before or after the action listener. You can use onclick to fire the script at the moment of the click. You can use onstart to fire the script at the moment the ajax request is about to be sent. But they will never exactly simultaneously be fired. The sequence is as follows:

  • User clicks button in client
  • onclick JavaScript code is executed
  • JavaScript prepares ajax request based on process and current HTML DOM tree
  • onstart JavaScript code is executed
  • JavaScript sends ajax request from client to server
  • JSF retrieves ajax request
  • JSF processes the request lifecycle on JSF component tree based on process
  • actionListener JSF backing bean method is executed
  • action JSF backing bean method is executed
  • JSF prepares ajax response based on update and current JSF component tree
  • JSF sends ajax response from server to client
  • JavaScript retrieves ajax response
    • if HTTP response status is 200, onsuccess JavaScript code is executed
    • else if HTTP response status is 500, onerror JavaScript code is executed
  • JavaScript performs update based on ajax response and current HTML DOM tree
  • oncomplete JavaScript code is executed

Note that the update is performed after actionListener, so if you were using onclick or onstart to show the dialog, then it may still show old content instead of updated content, which is poor for user experience. You'd then better use oncomplete instead to show the dialog. Also note that you'd better use action instead of actionListener when you intend to execute a business action.

See also:

Passing a variable from one php include file to another: global vs. not

Here is a pitfall to avoid. In case you need to access your variable $name within a function, you need to say "global $name;" at the beginning of that function. You need to repeat this for each function in the same file.

global $name;

function foo() {
  echo $name;

function bar() {
  echo $name;


will only show errors. The correct way to do that would be:


function foo() {
  global $name;
  echo $name;

function bar() {
  global $name;
  echo $name;


Get element of JS object with an index

I Hope that will help

$.each(myobj, function(index, value) { 



Can the Unix list command 'ls' output numerical chmod permissions?

You don't use ls to get a file's permission information. You use the stat command. It will give you the numerical values you want. The "Unix Way" says that you should invent your own script using ls (or 'echo *') and stat and whatever else you like to give the information in the format you desire.

What are the calling conventions for UNIX & Linux system calls (and user-space functions) on i386 and x86-64

Further reading for any of the topics here: The Definitive Guide to Linux System Calls

I verified these using GNU Assembler (gas) on Linux.

Kernel Interface

x86-32 aka i386 Linux System Call convention:

In x86-32 parameters for Linux system call are passed using registers. %eax for syscall_number. %ebx, %ecx, %edx, %esi, %edi, %ebp are used for passing 6 parameters to system calls.

The return value is in %eax. All other registers (including EFLAGS) are preserved across the int $0x80.

I took following snippet from the Linux Assembly Tutorial but I'm doubtful about this. If any one can show an example, it would be great.

If there are more than six arguments, %ebx must contain the memory location where the list of arguments is stored - but don't worry about this because it's unlikely that you'll use a syscall with more than six arguments.

For an example and a little more reading, refer to Another example of a Hello World for i386 Linux using int 0x80: Hello, world in assembly language with Linux system calls?

There is a faster way to make 32-bit system calls: using sysenter. The kernel maps a page of memory into every process (the vDSO), with the user-space side of the sysenter dance, which has to cooperate with the kernel for it to be able to find the return address. Arg to register mapping is the same as for int $0x80. You should normally call into the vDSO instead of using sysenter directly. (See The Definitive Guide to Linux System Calls for info on linking and calling into the vDSO, and for more info on sysenter, and everything else to do with system calls.)

x86-32 [Free|Open|Net|DragonFly]BSD UNIX System Call convention:

Parameters are passed on the stack. Push the parameters (last parameter pushed first) on to the stack. Then push an additional 32-bit of dummy data (Its not actually dummy data. refer to following link for more info) and then give a system call instruction int $0x80

x86-64 Linux System Call convention:

(Note: x86-64 Mac OS X is similar but different from Linux. TODO: check what *BSD does)

Refer to section: "A.2 AMD64 Linux Kernel Conventions" of System V Application Binary Interface AMD64 Architecture Processor Supplement. The latest versions of the i386 and x86-64 System V psABIs can be found linked from this page in the ABI maintainer's repo. (See also the tag wiki for up-to-date ABI links and lots of other good stuff about x86 asm.)

Here is the snippet from this section:

  1. User-level applications use as integer registers for passing the sequence %rdi, %rsi, %rdx, %rcx, %r8 and %r9. The kernel interface uses %rdi, %rsi, %rdx, %r10, %r8 and %r9.
  2. A system-call is done via the syscall instruction. This clobbers %rcx and %r11 as well as the %rax return value, but other registers are preserved.
  3. The number of the syscall has to be passed in register %rax.
  4. System-calls are limited to six arguments, no argument is passed directly on the stack.
  5. Returning from the syscall, register %rax contains the result of the system-call. A value in the range between -4095 and -1 indicates an error, it is -errno.
  6. Only values of class INTEGER or class MEMORY are passed to the kernel.

Remember this is from the Linux-specific appendix to the ABI, and even for Linux it's informative not normative. (But it is in fact accurate.)

This 32-bit int $0x80 ABI is usable in 64-bit code (but highly not recommended). What happens if you use the 32-bit int 0x80 Linux ABI in 64-bit code? It still truncates its inputs to 32-bit, so it's unsuitable for pointers, and it zeros r8-r11.

User Interface: function calling

x86-32 Function Calling convention:

In x86-32 parameters were passed on stack. Last parameter was pushed first on to the stack until all parameters are done and then call instruction was executed. This is used for calling C library (libc) functions on Linux from assembly.

Modern versions of the i386 System V ABI (used on Linux) require 16-byte alignment of %esp before a call, like the x86-64 System V ABI has always required. Callees are allowed to assume that and use SSE 16-byte loads/stores that fault on unaligned. But historically, Linux only required 4-byte stack alignment, so it took extra work to reserve naturally-aligned space even for an 8-byte double or something.

Some other modern 32-bit systems still don't require more than 4 byte stack alignment.

x86-64 System V user-space Function Calling convention:

x86-64 System V passes args in registers, which is more efficient than i386 System V's stack args convention. It avoids the latency and extra instructions of storing args to memory (cache) and then loading them back again in the callee. This works well because there are more registers available, and is better for modern high-performance CPUs where latency and out-of-order execution matter. (The i386 ABI is very old).

In this new mechanism: First the parameters are divided into classes. The class of each parameter determines the manner in which it is passed to the called function.

For complete information refer to : "3.2 Function Calling Sequence" of System V Application Binary Interface AMD64 Architecture Processor Supplement which reads, in part:

Once arguments are classified, the registers get assigned (in left-to-right order) for passing as follows:

  1. If the class is MEMORY, pass the argument on the stack.
  2. If the class is INTEGER, the next available register of the sequence %rdi, %rsi, %rdx, %rcx, %r8 and %r9 is used

So %rdi, %rsi, %rdx, %rcx, %r8 and %r9 are the registers in order used to pass integer/pointer (i.e. INTEGER class) parameters to any libc function from assembly. %rdi is used for the first INTEGER parameter. %rsi for 2nd, %rdx for 3rd and so on. Then call instruction should be given. The stack (%rsp) must be 16B-aligned when call executes.

If there are more than 6 INTEGER parameters, the 7th INTEGER parameter and later are passed on the stack. (Caller pops, same as x86-32.)

The first 8 floating point args are passed in %xmm0-7, later on the stack. There are no call-preserved vector registers. (A function with a mix of FP and integer arguments can have more than 8 total register arguments.)

Variadic functions (like printf) always need %al = the number of FP register args.

There are rules for when to pack structs into registers (rdx:rax on return) vs. in memory. See the ABI for details, and check compiler output to make sure your code agrees with compilers about how something should be passed/returned.

Note that the Windows x64 function calling convention has multiple significant differences from x86-64 System V, like shadow space that must be reserved by the caller (instead of a red-zone), and call-preserved xmm6-xmm15. And very different rules for which arg goes in which register.

Counting Number of Letters in a string variable

What is wrong with using string.Length?

// len will be 5
int len = "Hello".Length;

Specifying number of decimal places in Python

You don't show the code for display_data, but here's what you need to do:

print "$%0.02f" %amount

This is a format specifier for the variable amount.

Since this is beginner topic, I won't get into floating point rounding error, but it's good to be aware that it exists.

How to pass parameters using ui-sref in ui-router to controller

You don't necessarily need to have the parameters inside the URL.

For instance, with:

.state('home', {
  url: '/',
  views: {
    '': {
      templateUrl: 'home.html',
      controller: 'MainRootCtrl'

  params: {
    foo: null,
    bar: null

You will be able to send parameters to the state, using either:

$state.go('home', {foo: true, bar: 1});
// or
<a ui-sref="home({foo: true, bar: 1})">Go!</a>

Of course, if you reload the page once on the home state, you will loose the state parameters, as they are not stored anywhere.

A full description of this behavior is documented here, under the params row in the state(name, stateConfig) section.

How do you add input from user into list in Python

shopList = [] 
maxLengthList = 6
while len(shopList) < maxLengthList:
    item = input("Enter your Item to the List: ")
    print shopList
print "That's your Shopping List"
print shopList

Android Error Building Signed APK: keystore.jks not found for signing config 'externalOverride'

open and check your path is correct. (replace from \ to /)


replace from "storeFile=D:\Projects\Flutter\Key\key.jks" to "storeFile=D:/Projects/Flutter/Key/key.jks"

Multiple separate IF conditions in SQL Server

IF you are checking one variable against multiple condition then you would use something like this Here the block of code where the condition is true will be executed and other blocks will be ignored.

IF(@Var1 Condition1)
      /*Your Code Goes here*/

ELSE IF(@Var1 Condition2)
        /*Your Code Goes here*/ 

    ELSE      --<--- Default Task if none of the above is true
       /*Your Code Goes here*/

If you are checking conditions against multiple variables then you would have to go for multiple IF Statements, Each block of code will be executed independently from other blocks.

IF(@Var1 Condition1)
   /*Your Code Goes here*/

IF(@Var2 Condition1)
   /*Your Code Goes here*/

IF(@Var3 Condition1)
   /*Your Code Goes here*/

After every IF statement if there are more than one statement being executed you MUST put them in BEGIN..END Block. Anyway it is always best practice to use BEGIN..END blocks


Found something in your code some BEGIN END you are missing

ELSE IF(@ID IS NOT NULL AND @ID in (SELECT ID FROM Places))   -- Outer Most Block ELSE IF
     SELECT @MyName = Name ...  
    ...Some stuff....                       
    IF(SOMETHNG_1)         -- IF
        BEGIN TRY               
            UPDATE ....                                                                 
        END TRY

            SELECT ERROR_MESSAGE() AS 'Message' 
            RETURN -1
        END CATCH
                -- END
                 -- BEGIN
        BEGIN TRY
            UPDATE ...                                                      
        END TRY
            SELECT ERROR_MESSAGE() AS 'Message' 
            RETURN -1
        END CATCH   
               -- END
    ELSE                  -- ELSE
            BEGIN TRY
                UPDATE ...                                                              
            END TRY
            BEGIN CATCH
                SELECT ERROR_MESSAGE() AS 'Message' 
                RETURN -1
            END CATCH   
      --The above works I then insert this below and these if statement become nested----
          IF(@A!= @SA)
             exec Store procedure 
                    @FIELD = 15,
                    ... more params...
        IF(@S!= @SS)
             exec Store procedure 
                    @FIELD = 10,
                    ... more params...

Python: split a list based on a condition?

Not sure if this is a good approach but it can be done in this way as well

IMAGE_TYPES = ('.jpg','.jpeg','.gif','.bmp','.png')
files = [ ('file1.jpg', 33L, '.jpg'), ('file2.avi', 999L, '.avi')]
images, anims = reduce(lambda (i, a), f: (i + [f], a) if f[2] in IMAGE_TYPES else (i, a + [f]), files, ([], []))

How to Set/Update State of StatefulWidget from other StatefulWidget in Flutter?

Here is the solution which worked for me.

OUTPUT: State of Cart Widget is updated, upon addition of items.

enter image description here

Create a globalKey for the widget you want to update by calling the trigger from anywhere

final GlobalKey<CartWidgetState> cartKey = GlobalKey();

Make sure it's saved in a file have global access such that, it can be accessed from anywhere. I save it in globalClass where is save commonly used variables through the app's state.

class CartWidget extends StatefulWidget {

  CartWidget({Key key}) : super(key: key);
  CartWidgetState createState() => CartWidgetState();

class CartWidgetState extends State<CartWidget> {
  Widget build(BuildContext context) {
    //return your widget
    return Container();

Call your widget from some other class.

class HomeScreen extends StatefulWidget {

  HomeScreen ({Key key}) : super(key: key);
  HomeScreenState createState() => HomeScreen State();

class HomeScreen State extends State<HomeScreen> {
  Widget build(BuildContext context) {
    return ListView(

class ChildScreen extends StatefulWidget {

  ChildScreen ({Key key}) : super(key: key);
  ChildScreenState createState() => ChildScreen State();

class ChildScreen State extends State<ChildScreen> {
  Widget build(BuildContext context) {
    return InkWell(
              onTap: (){
                // This will update the state of your inherited widget/ class
                if (cartKey.currentState != null)
                    cartKey.currentState.setState(() {});
              child: Text("Update The State of external Widget"),

Global variable Python classes

What you have is correct, though you will not call it global, it is a class attribute and can be accessed via class e.g Shape.lolwut or via an instance e.g. shape.lolwut but be careful while setting it as it will set an instance level attribute not class attribute

class Shape(object):
    lolwut = 1

shape = Shape()

print Shape.lolwut,  # 1
print shape.lolwut,  # 1

# setting shape.lolwut would not change class attribute lolwut 
# but will create it in the instance
shape.lolwut = 2

print Shape.lolwut,  # 1
print shape.lolwut,  # 2

# to change class attribute access it via class
Shape.lolwut = 3

print Shape.lolwut,  # 3
print shape.lolwut   # 2 


1 1 1 2 3 2

Somebody may expect output to be 1 1 2 2 3 3 but it would be incorrect

How to run a command in the background and get no output?

These examples work fine:

nohup sh proglog.log 2>&1 &

For loop you can use like this :

for i in {1..10}; do sh; sleep 1; done prog.log 2>&1 &

It works in background and does not show any output.

Formatting ISODate from Mongodb

// from MongoDate object to Javascript Date object

var MongoDate = {sec: 1493016016, usec: 650000};
var dt = new Date("1970-01-01T00:00:00+00:00");

How do I convert an integer to string as part of a PostgreSQL query?

You could do this:

SELECT * FROM table WHERE cast(YOUR_INTEGER_VALUE as varchar) = 'string of numbers'

Check if multiple strings exist in another string

I would use this kind of function for speed:

def check_string(string, substring_list):
    for substring in substring_list:
        if substring in string:
            return True
    return False

Change image onmouseover

I know someone answered this the same way, but I made my own research, and I wrote this before to see that answer. So: I was looking for something simple with inline JavaScript, with just on the img, without "wrapping" it into the a tag (so instead of the document.MyImage, I used this.src)

src="ico/view.png" alt="hover effect" />

It works on all currently updated browsers; IE 11 (and I also tested it in the Developer Tools of IE from IE5 and above), Chrome, Firefox, Opera, Edge.

ImportError: No module named pandas

For me how it worked is, I have two executable versions of python so on pip install it was installing in one version but my executable path version is different so it failed, then I changed the path in sys's environment variable and installed in the executable version of python and it was able to identify the package from site-packages

Test file upload using HTTP PUT method

In my opinion the best tool for such testing is curl. Its --upload-file option uploads a file by PUT, which is exactly what you want (and it can do much more, like modifying HTTP headers, in case you need it):

curl http://myservice --upload-file file.txt

Save and load MemoryStream to/from a file

The combined answer for writing to a file can be;

MemoryStream ms = new MemoryStream();    
FileStream file = new FileStream("file.bin", FileMode.Create, FileAccess.Write);

Change image size with JavaScript

If you want to resize an image after it is loaded, you can attach to the onload event of the <img> tag. Note that it may not be supported in all browsers (Microsoft's reference claims it is part of the HTML 4.0 spec, but the HTML 4.0 spec doesn't list the onload event for <img>).

The code below is tested and working in: IE 6, 7 & 8, Firefox 2, 3 & 3.5, Opera 9 & 10, Safari 3 & 4 and Google Chrome:

<img src="yourImage.jpg" border="0" height="real_height" width="real_width"
    onload="resizeImg(this, 200, 100);">

<script type="text/javascript">
function resizeImg(img, height, width) {
    img.height = height;
    img.width = width;

How to config Tomcat to serve images from an external folder outside webapps?

You could have a redirect servlet. In you web.xml you'd have:


All your images would be in "/images", which would be intercepted by the servlet. It would then read in the relevant file in whatever folder and serve it right back out. For example, say you have a gif in your images folder, c:\Server_Images\smilie.gif. In the web page would be <img src="http:/".... In the servlet, HttpServletRequest.getPathInfo() would yield "/smilie.gif". Which the servlet would find in the folder.

How do I determine file encoding in OS X?

Classic 8-bit LaTeX is very restricted in which UTF8 characters it can use; it's highly dependent on the encoding of the font you're using and which glyphs that font has available.

Since you don't give a specific example, it's hard to know exactly where the problem is — whether you're attempting to use a glyph that your font doesn't have or whether you're not using the correct font encoding in the first place.

Here's a minimal example showing how a few UTF8 characters can be used in a LaTeX document:


You may have more luck with the [utf8x] encoding, but be slightly warned that it's no longer supported and has some idiosyncrasies compared with [utf8] (as far as I recall; it's been a while since I've looked at it). But if it does the trick, that's all that matters for you.

HorizontalAlignment=Stretch, MaxWidth, and Left aligned at the same time?

I would use SharedSizeGroup

        <ColumnDefinition SharedSizeGroup="col1"></ColumnDefinition>  
        <ColumnDefinition SharedSizeGroup="col2"></ColumnDefinition>
    <TextBox Background="Azure" Text="Hello" Grid.Column="1" MaxWidth="200" />

Proper use of const for defining functions in JavaScript

It has been three years since this question was asked, but I am just now coming across it. Since this answer is so far down the stack, please allow me to repeat it:

Q: I am interested if there are any limits to what types of values can be set using const in JavaScript—in particular functions. Is this valid? Granted it does work, but is it considered bad practice for any reason?

I was motivated to do some research after observing one prolific JavaScript coder who always uses const statement for functions, even when there is no apparent reason/benefit.

In answer to "is it considered bad practice for any reason?" let me say, IMO, yes it is, or at least, there are advantages to using function statement.

It seems to me that this is largely a matter of preference and style. There are some good arguments presented above, but none so clear as is done in this article:

Constant confusion: why I still use JavaScript function statements by Sourour, JavaScript guru, consultant, and teacher.

I urge everyone to read that article, even if you have already made a decision.

Here's are the main points:

Function statements have two clear advantages over [const] function expressions:

Advantage #1: Clarity of intent

When scanning through thousands of lines of code a day, it’s useful to be able to figure out the programmer’s intent as quickly and easily as possible.

Advantage #2: Order of declaration == order of execution

Ideally, I want to declare my code more or less in the order that I expect it will get executed.

This is the showstopper for me: any value declared using the const keyword is inaccessible until execution reaches it.

What I’ve just described above forces us to write code that looks upside down. We have to start with the lowest level function and work our way up.

My brain doesn’t work that way. I want the context before the details.

Most code is written by humans. So it makes sense that most people’s order of understanding roughly follows most code’s order of execution.

How to sort an object array by date property?

["12 Jan 2018" , "1 Dec 2018", "04 May 2018"].sort(function(a,b) {
    return new Date(a).getTime() - new Date(b).getTime()

ADB Shell Input Events

One other difference:

  • "adb shell input" is calling the input.jar to process and send the keycode from the Java layer of the android framework.
  • "adb sendevent" is actually c code (part of toolbox utility ) that sends the input code directly into the /dev/input.... of Linux input subsystem.

More detail code trace into inside AOSP Framework can be found here:

How to re-sync the Mysql DB if Master and slave have different database incase of Mysql replication?

Adding to the popular answer to include this error:

"ERROR 1200 (HY000): The server is not configured as slave; fix in config file or with CHANGE MASTER TO",

Replication from slave in one shot:

In one terminal window:

mysql -h <Master_IP_Address> -uroot -p

After connecting,


The status appears as below: Note that position number varies!

| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
| mysql-bin.000001 |      98  | your_DB      |                  |

Export the dump similar to how he described "using another terminal"!

Exit and connect to your own DB(which is the slave):

mysql -u root -p

The type the below commands:


Import the Dump as mentioned (in another terminal, of course!) and type the below commands:

  MASTER_HOST = 'Master_IP_Address', 
  MASTER_USER = 'your_Master_user', // usually the "root" user
  MASTER_PASSWORD = 'Your_MasterDB_Password', 
  MASTER_PORT = 3306, 
  MASTER_LOG_FILE = 'mysql-bin.000001', 
  MASTER_LOG_POS = 98; // In this case

Once logged, set the server_id parameter (usually, for new / non-replicated DBs, this is not set by default),

set global server_id=4000;

Now, start the slave.


The output should be the same as he described.

  Slave_IO_Running: Yes
  Slave_SQL_Running: Yes

Note: Once replicated, the master and slave share the same password!

Rename a table in MySQL

You can use

RENAME TABLE `group` TO `member`;

Use back tick (`) instead of single quote (').

Google Chrome: This setting is enforced by your administrator

for me the default search in chrome was locked by and deleting all the entries in registry and also resetting and reinstalling chrome did not helped . except the below solution.

  1. Delete related key from the registry entry- Computer\HKEY_LOCAL_MACCHINE\SOFTWARE\Policies\Google\Chrome
  2. Delete file - C:\Windows\System32\GroupPolicy\Machine\registry.pol
  3. Restart computer and the problem will be solved

reddit source

How does one make random number between range for arc4random_uniform()?

The answer is just 1 line code:

let randomNumber = arc4random_uniform(8999) + 1000 //for 4 digit random number
let randomNumber = arc4random_uniform(899999999) + 100000000 //for 9 digit random number
let randomNumber = arc4random_uniform(89) + 10    //for 2 digit random number
let randomNumber = arc4random_uniform(899) + 100  //for 3 digit random number

The alternate solution is:

    func generateRandomNumber(numDigits: Int) -> Int{
    var place = 1
    var finalNumber = 0;
    var finanum = 0;
    for var i in 0 ..< numDigits {
        place *= 10
        let randomNumber = arc4random_uniform(10)         
        finalNumber += Int(randomNumber) * place
        finanum = finalNumber / 10
           i += 1
    return finanum

Although the drawback is that number cannot start from 0.

There is already an object named in the database

I was facing the same issue. I tried below solution : 1. deleted create table code from Up() and related code from Down() method 2. Run update-database command in Package Manager Consol

this solved my problem