Programs & Examples On #Nonclient

Check/Uncheck checkbox with JavaScript

Important behaviour that has not yet been mentioned:

Programmatically setting the checked attribute, does not fire the change event of the checkbox.

See for yourself in this fiddle:

(Fiddle tested in Chrome 46, Firefox 41 and IE 11)

The click() method

Some day you might find yourself writing code, which relies on the event being fired. To make sure the event fires, call the click() method of the checkbox element, like this:


However, this toggles the checked status of the checkbox, instead of specifically setting it to true or false. Remember that the change event should only fire, when the checked attribute actually changes.

It also applies to the jQuery way: setting the attribute using prop or attr, does not fire the change event.

Setting checked to a specific value

You could test the checked attribute, before calling the click() method. Example:

function toggle(checked) {
  var elm = document.getElementById('checkbox');
  if (checked != elm.checked) {;

Read more about the click method here:

Set cellpadding and cellspacing in CSS?

Just use border-collapse: collapse for your table, and padding for th or td.

How to update large table with millions of rows in SQL Server?

I want share my experience. A few days ago I have to update 21 million records in table with 76 million records. My colleague suggested the next variant. For example, we have the next table 'Persons':

Id | FirstName | LastName | Email            | JobTitle
1  | John      |  Doe     | [email protected]     | Software Developer
2  | John1     |  Doe1    | [email protected]     | Software Developer
3  | John2     |  Doe2    | [email protected]     | Web Designer

Task: Update persons to the new Job Title: 'Software Developer' -> 'Web Developer'.

1. Create Temporary Table 'Persons_SoftwareDeveloper_To_WebDeveloper (Id INT Primary Key)'

2. Select into temporary table persons which you want to update with the new Job Title:

INSERT INTO Persons_SoftwareDeveloper_To_WebDeveloper SELECT Id FROM
Persons WITH(NOLOCK) --avoid lock 
WHERE JobTitle = 'Software Developer' 
OPTION(MAXDOP 1) -- use only one core

Depends on rows count, this statement will take some time to fill your temporary table, but it would avoid locks. In my situation it took about 5 minutes (21 million rows).

3. The main idea is to generate micro sql statements to update database. So, let's print them:

DECLARE @i INT, @pagesize INT, @totalPersons INT
    SET @i=0
    SET @pagesize=2000
    SELECT @totalPersons = MAX(Id) FROM Persons

    while @i<= @totalPersons
    Print '
    UPDATE persons 
      SET persons.JobTitle = ''ASP.NET Developer''
      FROM  Persons_SoftwareDeveloper_To_WebDeveloper tmp
      JOIN Persons persons ON tmp.Id = persons.Id
      where persons.Id between '+cast(@i as varchar(20)) +' and '+cast(@i+@pagesize as varchar(20)) +' 
        PRINT ''Page ' + cast((@i / @pageSize) as varchar(20))  + ' of ' + cast(@totalPersons/@pageSize as varchar(20))+'
     set @i=@i+@pagesize

After executing this script you will receive hundreds of batches which you can execute in one tab of MS SQL Management Studio.

4. Run printed sql statements and check for locks on table. You always can stop process and play with @pageSize to speed up or speed down updating(don't forget to change @i after you pause script).

5. Drop Persons_SoftwareDeveloper_To_AspNetDeveloper. Remove temporary table.

Minor Note: This migration could take a time and new rows with invalid data could be inserted during migration. So, firstly fix places where your rows adds. In my situation I fixed UI, 'Software Developer' -> 'Web Developer'.

Determine if map contains a value for a key?

I just noticed that with C++20, we will have

bool std::map::contains( const Key& key ) const;

That will return true if map holds an element with key key.

How to select all and copy in vim?

There are a few important informations missing from your question:

  • output of $ vim --version?
  • OS?
  • CLI or GUI?
  • local or remote?
  • do you use tmux? screen?

If your Vim was built with clipboard support, you are supposed to use the clipboard register like this, in normal mode:


If your Vim doesn't have clipboard support, you can manage to copy text from Vim to your OS clipboard via other programs. This pretty much depends on your OS but you didn't say what it is so we can't really help.

However, if your Vim is crippled, the best thing to do is to install a proper build with clipboard support but I can't tell you how either because I don't know what OS you use.


On debian based systems, the following command will install a proper Vim with clipboard, ruby, python… support.

$ sudo apt-get install vim-gnome

Select DISTINCT individual columns in django?

The other answers are fine, but this is a little cleaner, in that it only gives the values like you would get from a DISTINCT query, without any cruft from Django.

>>> set(ProductOrder.objects.values_list('category', flat=True))
{u'category1', u'category2', u'category3', u'category4'}


>>> list(set(ProductOrder.objects.values_list('category', flat=True)))
[u'category1', u'category2', u'category3', u'category4']

And, it works without PostgreSQL.

This is less efficient than using a .distinct(), presuming that DISTINCT in your database is faster than a python set, but it's great for noodling around the shell.

How to get file's last modified date on Windows command line?

Change % to %% for use in batch file, for %~ta syntax enter call /?

for %a in (MyFile.txt) do set FileDate=%~ta

Sample output:

for %a in (MyFile.txt) do set FileDate=%~ta
set FileDate=05/05/2020 09:47 AM

for %a in (file_not_exist_file.txt) do set FileDate=%~ta
set FileDate=

Oracle row count of table by count(*) vs NUM_ROWS from DBA_TABLES

According to the documentation NUM_ROWS is the "Number of rows in the table", so I can see how this might be confusing. There, however, is a major difference between these two methods.

This query selects the number of rows in MY_TABLE from a system view. This is data that Oracle has previously collected and stored.

select num_rows from all_tables where table_name = 'MY_TABLE'

This query counts the current number of rows in MY_TABLE

select count(*) from my_table

By definition they are difference pieces of data. There are two additional pieces of information you need about NUM_ROWS.

  1. In the documentation there's an asterisk by the column name, which leads to this note:

    Columns marked with an asterisk (*) are populated only if you collect statistics on the table with the ANALYZE statement or the DBMS_STATS package.

    This means that unless you have gathered statistics on the table then this column will not have any data.

  2. Statistics gathered in 11g+ with the default estimate_percent, or with a 100% estimate, will return an accurate number for that point in time. But statistics gathered before 11g, or with a custom estimate_percent less than 100%, uses dynamic sampling and may be incorrect. If you gather 99.999% a single row may be missed, which in turn means that the answer you get is incorrect.

If your table is never updated then it is certainly possible to use ALL_TABLES.NUM_ROWS to find out the number of rows in a table. However, and it's a big however, if any process inserts or deletes rows from your table it will be at best a good approximation and depending on whether your database gathers statistics automatically could be horribly wrong.

Generally speaking, it is always better to actually count the number of rows in the table rather then relying on the system tables.

How to change ReactJS styles dynamically?

Ok, finally found the solution.

Probably due to lack of experience with ReactJS and web development...

    var Task = React.createClass({
    render: function() {
      var percentage = this.props.children + '%';
        <div className="ui-progressbar-value ui-widget-header ui-corner-left" style={{width : percentage}}/>

I created the percentage variable outside in the render function.

Fire event on enter key press for a textbox

My 2c.. I have used javascript, but found it did things that were not quite expected.

USE the panel's defaultButton attribute/property as many of the above posts suggest. It is reliable (EASY) and works in all the browsers I have tested it on.

how to get the attribute value of an xml node using java


document.getElementsByTagName(" * ");

to get all XML elements from within an XML file, this does however return repeating attributes


NodeList list = doc.getElementsByTagName("*");

System.out.println("XML Elements: ");

        for (int i=0; i<list.getLength(); i++) {

            Element element = (Element)list.item(i);

Bootstrap: How to center align content inside column?

You can do this by adding a div i.e. centerBlock. And give this property in CSS to center the image or any content. Here is the code:

<div class="container">
    <div class="row">
        <div class="col-sm-4 col-md-4 col-lg-4">
            <div class="centerBlock">
                <img class="img-responsive" src="img/some-image.png" title="This image needs to be centered">
        <div class="col-sm-8 col-md-8 col-lg-8">
            Some content not important at this moment

// CSS

.centerBlock {
  display: table;
  margin: auto;

How to compare data between two table in different databases using Sql Server 2008?

Comparing the two Databases in SQL Database. Try this Query it may help.

SELECT T.[name] AS [table_name], AC.[name] AS [column_name],  TY.[name] AS 
   system_data_type FROM    [***Database Name 1***].sys.[tables] AS T  
   INNER JOIN [***Database Name 1***].sys.[all_columns] AC ON T.[object_id] = AC.[object_id]      
   INNER JOIN [***Database Name 1***].sys.[types] TY ON AC.[system_type_id] = TY.[system_type_id] 
   EXCEPT SELECT T.[name] AS [table_name], AC.[name] AS [column_name], TY.[name] AS system_data_type FROM    ***Database Name 2***.sys.[tables] AS T  
   INNER JOIN ***Database Name 2***.sys.[all_columns] AC ON T.[object_id] = AC.[object_id]  
   INNER JOIN ***Database Name 2***.sys.[types] TY ON AC.[system_type_id] = TY.[system_type_id]

PHP code is not being executed, instead code shows on the page

php7 :

sudo a2enmod proxy_fcgi setenvif
sudo a2enconf php7.0-fpm
sudo service apache2 restart

Is it possible to set an object to null?

While it is true that an object cannot be "empty/null" in C++, in C++17, we got std::optional to express that intent.

Example use:

std::optional<int> v1;      // "empty" int
std::optional<int> v2(3);   // Not empty, "contains a 3"

You can then check if the optional contains a value with

v1.has_value(); // false


if(v2) {
    // You get here if v2 is not empty

A plain int (or any type), however, can never be "null" or "empty" (by your definition of those words) in any useful sense. Think of std::optional as a container in this regard.

If you don't have a C++17 compliant compiler at hand, you can use boost.optional instead. Some pre-C++17 compilers also offer std::experimental::optional, which will behave at least close to the actual std::optional afaik. Check your compiler's manual for details.

Positioning background image, adding padding

There is actually a native solution to this, using the four-values to background-position

.CssClass {background-position: right 10px top 20px;}

This means 10px from right and 20px from top. you can also use three values the fourth value will be count as 0.

Twitter bootstrap float div right

You can assign the class name like text-center, left or right. The text will align accordingly to these class name. You don't need to make extra class name separately. These classes are built in BootStrap 3 and bootstrap 4.

Bootstrap 3

v3 Text Alignment Docs

<p class="text-left">Left aligned text.</p>
<p class="text-center">Center aligned text.</p>
<p class="text-right">Right aligned text.</p>
<p class="text-justify">Justified text.</p>
<p class="text-nowrap">No wrap text.</p>

Bootstrap 4

v4 Text Alignment Docs

<p class="text-xs-left">Left aligned text on all viewport sizes.</p>
<p class="text-xs-center">Center aligned text on all viewport sizes.</p>
<p class="text-xs-right">Right aligned text on all viewport sizes.</p>

<p class="text-sm-left">Left aligned text on viewports sized SM (small) or wider.</p>
<p class="text-md-left">Left aligned text on viewports sized MD (medium) or wider.</p>
<p class="text-lg-left">Left aligned text on viewports sized LG (large) or wider.</p>
<p class="text-xl-left">Left aligned text on viewports sized XL (extra-large) or wider.</p>

Split a python list into other "sublists" i.e smaller lists

Actually I think using plain slices is the best solution in this case:

for i in range(0, len(data), 100):
    chunk = data[i:i + 100]

If you want to avoid copying the slices, you could use itertools.islice(), but it doesn't seem to be necessary here.

The itertools() documentation also contains the famous "grouper" pattern:

def grouper(n, iterable, fillvalue=None):
    "grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx"
    args = [iter(iterable)] * n
    return izip_longest(fillvalue=fillvalue, *args)

You would need to modify it to treat the last chunk correctly, so I think the straight-forward solution using plain slices is preferable.

How to import functions from different js file in a Vue+webpack+vue-loader project

I was trying to organize my vue app code, and came across this question , since I have a lot of logic in my component and can not use other sub-coponents , it makes sense to use many functions in a separate js file and call them in the vue file, so here is my attempt

1)The Component (.vue file)

//MyComponent.vue file
  <div>Hello {{name}}</div>
  <button @click="function_A">Read Name</button>
  <button @click="function_B">Write Name</button>
  <button @click="function_C">Reset</button>

import Mylib from "./Mylib"; // <-- import
export default {
  name: "MyComponent",
  data() {
    return {
      name: "Bob",
      message: "click on the buttons"
  methods: {
    function_A() {
      Mylib.myfuncA(this); // <---read data
    function_B() {
      Mylib.myfuncB(this); // <---write data
    function_C() {
      Mylib.myfuncC(this); // <---write data

2)The External js file

let exports = {};

// this (vue instance) is passed as that , so we
// can read and write data from and to it as we please :)
exports.myfuncA = (that) => {
  that.message =
  "you hit ''myfuncA'' function that is located in Mylib.js  and = " +;

exports.myfuncB = (that) => {
  that.message =
  "you hit ''myfuncB'' function that is located in Mylib.js and now I will change the name to Nassim"; = "Nassim"; // <-- change name to Nassim

exports.myfuncC = (that) => {
  that.message =
  "you hit ''myfuncC'' function that is located in Mylib.js and now I will change the name back to Bob"; = "Bob"; // <-- change name to Bob

export default exports;

enter image description here 3)see it in action :


after getting more experience with Vue , I found out that you could use mixins too to split your code into different files and make it easier to code and maintain see

Unique random string generation

Using Guid would be a pretty good way, but to get something looking like your example, you probably want to convert it to a Base64 string:

    Guid g = Guid.NewGuid();
    string GuidString = Convert.ToBase64String(g.ToByteArray());
    GuidString = GuidString.Replace("=","");
    GuidString = GuidString.Replace("+","");

I get rid of "=" and "+" to get a little closer to your example, otherwise you get "==" at the end of your string and a "+" in the middle. Here's an example output string:


What's the best way to override a user agent CSS stylesheet rule that gives unordered-lists a 1em margin?

put this in your "head" of your index.html

  html body{
    left: 0;
    right: 0;
    bottom: 0;
    top: 0;
    margin: 0;

How to find the 'sizeof' (a pointer pointing to an array)?

There is a clean solution with C++ templates, without using sizeof(). The following getSize() function returns the size of any static array:

#include <cstddef>

template<typename T, size_t SIZE>
size_t getSize(T (&)[SIZE]) {
    return SIZE;

Here is an example with a foo_t structure:

#include <cstddef>

template<typename T, size_t SIZE>
size_t getSize(T (&)[SIZE]) {
    return SIZE;

struct foo_t {
    int ball;

int main()
    foo_t foos3[] = {{1},{2},{3}};
    foo_t foos5[] = {{1},{2},{3},{4},{5}};
    printf("%u\n", getSize(foos3));
    printf("%u\n", getSize(foos5));

    return 0;



How to get info on sent PHP curl request

curl_getinfo() must be added before closing the curl handler

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "");
curl_setopt($ch, CURLOPT_USERPWD, "someusername:secretpassword");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLINFO_HEADER_OUT, true);
$info = curl_getinfo($ch);

How to read and write into file using JavaScript?

For Firefox:

var file = Components.classes[";1"].


For others, check out the TiddlyWiki app to see how it does it.

How to import .py file from another directory?

You can add to the system-path at runtime:

import sys
sys.path.insert(0, 'path/to/your/py_file')

import py_file

This is by far the easiest way to do it.

How to add two edit text fields in an alert dialog

 LayoutInflater factory = LayoutInflater.from(this);
final View textEntryView = factory.inflate(R.layout.text_entry, null);
//text_entry is an Layout XML file containing two text field to display in alert dialog
final EditText input1 = (EditText) textEntryView.findViewById(;
final EditText input2 = (EditText) textEntryView.findViewById(;             
input1.setText("DefaultValue", TextView.BufferType.EDITABLE);
input2.setText("DefaultValue", TextView.BufferType.EDITABLE);
final AlertDialog.Builder alert = new AlertDialog.Builder(this);

     .setTitle("Enter the Text:")
         new DialogInterface.OnClickListener() {
             public void onClick(DialogInterface dialog, int whichButton) {
                    Log.i("AlertDialog","TextEntry 1 Entered "+input1.getText().toString());
                    Log.i("AlertDialog","TextEntry 2 Entered "+input2.getText().toString());
                    /* User clicked OK so do some stuff */
         new DialogInterface.OnClickListener() {
             public void onClick(DialogInterface dialog,
                    int whichButton) {

Add multiple items to already initialized arraylist in java

If you needed to add a lot of integers it'd proabbly be easiest to use a for loop. For example, adding 28 days to a daysInFebruary array.

ArrayList<Integer> daysInFebruary = new ArrayList<>();

for(int i = 1; i <= 28; i++) {

Recommended way to embed PDF in HTML?

PdfToImageServlet using ImageMagick's convert command.

Usage example: <img src='/webAppDirectory/PdfToImageServlet?pdfFile=/usr/share/cups/data/default-testpage.pdf'>

What's the difference setting Embed Interop Types true and false in Visual Studio?

I noticed that when it's set to false, I'm able to see the value of an item using the debugger. When it was set to true, I was getting an error - item.FullName.GetValue The embedded interop type 'FullName' does not contain a definition for 'QBFC11Lib.IItemInventoryRet' since it was not used in the compiled assembly. Consider casting to object or changing the 'Embed Interop Types' property to true.

jQuery remove options from select

if your dropdown is in a table and you do not have id for it then you can use the following jquery:

var select_object = purchasing_table.rows[row_index].cells[cell_index].childNodes[1];

How do I use SELECT GROUP BY in DataTable.Select(Expression)?

    .GroupBy(r => new { Col1 = r["Col1"], Col2 = r["Col2"] })
    .Select(g =>
        var row = dt.NewRow();

        row["PK"] = g.Min(r => r.Field<int>("PK"));
        row["Col1"] = g.Key.Col1;
        row["Col2"] = g.Key.Col2;

        return row;


How do I get the width and height of a HTML5 canvas?

now starting 2015 all (major?) browsers seem to alow c.width and c.height to get the canvas internal size, but:

the question as the answers are missleading, because the a canvas has in principle 2 different/independent sizes.

The "html" lets say CSS width/height and its own (attribute-) width/height

look at this short example of different sizing, where I put a 200/200 canvas into a 300/100 html-element

With most examples (all I saw) there is no css-size set, so theese get implizit the width and height of the (drawing-) canvas size. But that is not a must, and can produce funy results, if you take the wrong size - ie. css widht/height for inner positioning.

Remove ListView items in Android

            names = db.getSites();
            la = new ArrayAdapter<String>(EditSiteList.this,
                    android.R.layout.simple_list_item_1, names);

this code works fine for me.

MATLAB - multiple return values from a function?

Matlab allows you to return multiple values as well as receive them inline.

When you call it, receive individual variables inline:

[array, listp, freep] = initialize(size)

Export from pandas to_excel without row names (index)?

Example: index = False

import pandas as pd

writer = pd.ExcelWriter("dataframe.xlsx", engine='xlsxwriter')
dataframe.to_excel(writer,sheet_name = dataframe, index=False) 

Darken CSS background image?

You can use the CSS3 Linear Gradient property along with your background-image like this:

#landing-wrapper {
    background: linear-gradient( rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5) ), url('landingpagepic.jpg');
    background-position:center top;

Here's a demo:

#landing-wrapper {_x000D_
  display: table;_x000D_
  width: 100%;_x000D_
  background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), url('');_x000D_
  background-position: center top;_x000D_
  height: 350px;_x000D_
  color: white;_x000D_
<div id="landing-wrapper">Lorem ipsum dolor ismet.</div>

How to open spss data files in excel?

(Not exactly an answer for you, since do you want avoid opening the files, but maybe this helps others).

I have been using the open source GNU PSPP package to convert the sav tile to csv. You can download the Windows version at least from SourceForge [1]. Once you have the software, you can convert sav file to csv with following command line:

pspp-convert <input.sav> <output.csv>


How can I run an external command asynchronously from Python?

I have the same problem trying to connect to an 3270 terminal using the s3270 scripting software in Python. Now I'm solving the problem with an subclass of Process that I found here:

And here is the sample taken from file:

def recv_some(p, t=.1, e=1, tr=5, stderr=0):
    if tr < 1:
        tr = 1
    x = time.time()+t
    y = []
    r = ''
    pr = p.recv
    if stderr:
        pr = p.recv_err
    while time.time() < x or r:
        r = pr()
        if r is None:
            if e:
                raise Exception(message)
        elif r:
            time.sleep(max((x-time.time())/tr, 0))
    return ''.join(y)

def send_all(p, data):
    while len(data):
        sent = p.send(data)
        if sent is None:
            raise Exception(message)
        data = buffer(data, sent)

if __name__ == '__main__':
    if sys.platform == 'win32':
        shell, commands, tail = ('cmd', ('dir /w', 'echo HELLO WORLD'), '\r\n')
        shell, commands, tail = ('sh', ('ls', 'echo HELLO WORLD'), '\n')

    a = Popen(shell, stdin=PIPE, stdout=PIPE)
    print recv_some(a),
    for cmd in commands:
        send_all(a, cmd + tail)
        print recv_some(a),
    send_all(a, 'exit' + tail)
    print recv_some(a, e=0)

Disabled form inputs do not appear in the request

Using Jquery and sending the data with ajax, you can solve your problem:


$('#form_id').submit(function() {
    $("#input_disabled_id").prop('disabled', false);

    //Rest of code

Open Url in default web browser

In React 16.8+, using functional components, you would do

import React from 'react';
import { Button, Linking } from 'react-native';

const ExternalLinkBtn = (props) => {
  return <Button
            onPress={() => {
                .catch(err => {
                    console.error("Failed opening page because: ", err)
                    alert('Failed to open page')

export default function exampleUse() {
  return (
      <ExternalLinkBtn title="Example Link" url="" />

What is Domain Driven Design?

As in TDD & BDD you/ team focus the most on test and behavior of the system than code implementation.

Similar way when system analyst, product owner, development team and ofcourse the code - entities/ classes, variables, functions, user interfaces processes communicate using the same language, its called Domain Driven Design

DDD is a thought process. When modeling a design of software you need to keep business domain/process in the center of attention rather than data structures, data flows, technology, internal and external dependencies.

There are many approaches to model systerm using DDD

  • event sourcing (using events as a single source of truth)
  • relational databases
  • graph databases
  • using functional languages

Domain object:

In very naive words, an object which

  • has name based on business process/flow
  • has complete control on its internal state i.e exposes methods to manipulate state.
  • always fulfill all business invariants/business rules in context of its use.
  • follows single responsibility principle

How to strip HTML tags with jQuery?

Use the .text() function:

var text = $("<p> example ive got a string</P>").text();

Update: As Brilliand points out below, if the input string does not contain any tags and you are unlucky enough, it might be treated as a CSS selector. So this version is more robust:

var text = $("<div/>").html("<p> example ive got a string</P>").text();

What are the differences between NP, NP-Complete and NP-Hard?

In addition to the other great answers, here is the typical schema people use to show the difference between NP, NP-Complete, and NP-Hard:

enter image description here

How do I choose grid and block dimensions for CUDA kernels?

There are two parts to that answer (I wrote it). One part is easy to quantify, the other is more empirical.

Hardware Constraints:

This is the easy to quantify part. Appendix F of the current CUDA programming guide lists a number of hard limits which limit how many threads per block a kernel launch can have. If you exceed any of these, your kernel will never run. They can be roughly summarized as:

  1. Each block cannot have more than 512/1024 threads in total (Compute Capability 1.x or 2.x and later respectively)
  2. The maximum dimensions of each block are limited to [512,512,64]/[1024,1024,64] (Compute 1.x/2.x or later)
  3. Each block cannot consume more than 8k/16k/32k/64k/32k/64k/32k/64k/32k/64k registers total (Compute 1.0,1.1/1.2,1.3/2.x-/3.0/3.2/3.5-5.2/5.3/6-6.1/6.2/7.0)
  4. Each block cannot consume more than 16kb/48kb/96kb of shared memory (Compute 1.x/2.x-6.2/7.0)

If you stay within those limits, any kernel you can successfully compile will launch without error.

Performance Tuning:

This is the empirical part. The number of threads per block you choose within the hardware constraints outlined above can and does effect the performance of code running on the hardware. How each code behaves will be different and the only real way to quantify it is by careful benchmarking and profiling. But again, very roughly summarized:

  1. The number of threads per block should be a round multiple of the warp size, which is 32 on all current hardware.
  2. Each streaming multiprocessor unit on the GPU must have enough active warps to sufficiently hide all of the different memory and instruction pipeline latency of the architecture and achieve maximum throughput. The orthodox approach here is to try achieving optimal hardware occupancy (what Roger Dahl's answer is referring to).

The second point is a huge topic which I doubt anyone is going to try and cover it in a single StackOverflow answer. There are people writing PhD theses around the quantitative analysis of aspects of the problem (see this presentation by Vasily Volkov from UC Berkley and this paper by Henry Wong from the University of Toronto for examples of how complex the question really is).

At the entry level, you should mostly be aware that the block size you choose (within the range of legal block sizes defined by the constraints above) can and does have a impact on how fast your code will run, but it depends on the hardware you have and the code you are running. By benchmarking, you will probably find that most non-trivial code has a "sweet spot" in the 128-512 threads per block range, but it will require some analysis on your part to find where that is. The good news is that because you are working in multiples of the warp size, the search space is very finite and the best configuration for a given piece of code relatively easy to find.

Add property to an array of objects

You can use the forEach method to execute a provided function once for each element in the array. In this provided function you can add the Active property to the element.

Results.forEach(function (element) {
  element.Active = "false";

C# ASP.NET MVC Return to Previous Page

I am assuming (please correct me if I am wrong) that you want to re-display the edit page if the edit fails and to do this you are using a redirect.

You may have more luck by just returning the view again rather than trying to redirect the user, this way you will be able to use the ModelState to output any errors too.


Updated based on feedback. You can place the previous URL in the viewModel, add it to a hidden field then use it again in the action that saves the edits.

For instance:

public ActionResult Index()
    return View();

[HttpGet] // This isn't required
public ActionResult Edit(int id)
   // load object and return in view
   ViewModel viewModel = Load(id);

   // get the previous url and store it with view model
   viewModel.PreviousUrl = System.Web.HttpContext.Current.Request.UrlReferrer;

   return View(viewModel);

public ActionResult Edit(ViewModel viewModel)
   // Attempt to save the posted object if it works, return index if not return the Edit view again

   bool success = Save(viewModel);
   if (success)
       return Redirect(viewModel.PreviousUrl);
      ModelState.AddModelError("There was an error");
      return View(viewModel);

The BeginForm method for your view doesn't need to use this return URL either, you should be able to get away with:

@model ViewModel

@using (Html.BeginForm())
    <input type="hidden" name="PreviousUrl" value="@Model.PreviousUrl" />

Going back to your form action posting to an incorrect URL, this is because you are passing a URL as the 'id' parameter, so the routing automatically formats your URL with the return path.

This won't work because your form will be posting to an controller action that won't know how to save the edits. You need to post to your save action first, then handle the redirect within it.

How can I change the default Mysql connection timeout when connecting through python?

You change default value in MySQL configuration file (option connect_timeout in mysqld section) -


If this file is not accessible for you, then you can set this value using this statement -

SET GLOBAL connect_timeout=100;

What's the difference between a 302 and a 307 redirect?

EXPECTED for 302: redirect uses same request method POST on NEW_URL


ACTUAL for 302, 303: redirect changes request method from POST to GET on NEW_URL


ACTUAL for 307: redirect uses same request method POST on NEW_URL


Special characters like @ and & in cURL POST data

cURL > 7.18.0 has an option --data-urlencode which solves this problem. Using this, I can simply send a POST request as

curl -d name=john --data-urlencode passwd=@31&3*J

How to solve SyntaxError on autogenerated

You must activate virtual environment where you have installed django. Then run this command - python runserver

How to use "svn export" command to get a single file from the repository?

Use SVN repository URL to export file to Local path.

     svn export [-r rev] [--ignore-externals] URL Export_PATH
     svn export http://<path>/test.txt C:\Temp-Folder

How to add one day to a date?

I found a simple method to add arbitrary time to a Date object

Date d = new Date(new Date().getTime() + 86400000)


86 400 000ms = 1 Day  : 24*60*60*1000
 3 600 000ms = 1 Hour :    60*60*1000

Random float number generation

C++11 gives you a lot of new options with random. The canonical paper on this topic would be N3551, Random Number Generation in C++11

To see why using rand() can be problematic see the rand() Considered Harmful presentation material by Stephan T. Lavavej given during the GoingNative 2013 event. The slides are in the comments but here is a direct link.

I also cover boost as well as using rand since legacy code may still require its support.

The example below is distilled from the cppreference site and uses the std::mersenne_twister_engine engine and the std::uniform_real_distribution which generates numbers in the [0,10) interval, with other engines and distributions commented out (see it live):

#include <iostream>
#include <iomanip>
#include <string>
#include <map>
#include <random>

int main()
    std::random_device rd;

    // Engines 
    std::mt19937 e2(rd());
    //std::knuth_b e2(rd());
    //std::default_random_engine e2(rd()) ;

    // Distribtuions
    std::uniform_real_distribution<> dist(0, 10);
    //std::normal_distribution<> dist(2, 2);
    //std::student_t_distribution<> dist(5);
    //std::poisson_distribution<> dist(2);
    //std::extreme_value_distribution<> dist(0,2);

    std::map<int, int> hist;
    for (int n = 0; n < 10000; ++n) {

    for (auto p : hist) {
        std::cout << std::fixed << std::setprecision(1) << std::setw(2)
                  << p.first << ' ' << std::string(p.second/200, '*') << '\n';

output will be similar to the following:

0 ****
1 ****
2 ****
3 ****
4 *****
5 ****
6 *****
7 ****
8 *****
9 ****

The output will vary depending on which distribution you choose, so if we decided to go with std::normal_distribution with a value of 2 for both mean and stddev e.g. dist(2, 2) instead the output would be similar to this (see it live):

-2 **
-1 ****
 0 *******
 1 *********
 2 *********
 3 *******
 4 ****
 5 **

The following is a modified version of some of the code presented in N3551 (see it live) :

#include <algorithm>
#include <array>
#include <iostream>
#include <random>

std::default_random_engine & global_urng( )
    static std::default_random_engine u{};
    return u ;

void randomize( )
    static std::random_device rd{};
    global_urng().seed( rd() );

int main( )
  // Manufacture a deck of cards:
  using card = int;
  std::array<card,52> deck{};
  std::iota(deck.begin(), deck.end(), 0);

  randomize( ) ;  

  std::shuffle(deck.begin(), deck.end(), global_urng());
  // Display each card in the shuffled deck:
  auto suit = []( card c ) { return "SHDC"[c / 13]; };
  auto rank = []( card c ) { return "AKQJT98765432"[c % 13]; };

  for( card c : deck )
      std::cout << ' ' << rank(c) << suit(c);

   std::cout << std::endl;

Results will look similar to:

5H 5S AS 9S 4D 6H TH 6D KH 2S QS 9H 8H 3D KC TD 7H 2D KS 3C TC 7D 4C QH QC QD JD AH JC AC KD 9D 5C 2H 4H 9C 8C JH 5D 4S 7C AD 3S 8S TS 2C 8D 3H 6C JS 7S 6S


Of course Boost.Random is always an option as well, here I am using boost::random::uniform_real_distribution:

#include <iostream>
#include <iomanip>
#include <string>
#include <map>
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_real_distribution.hpp>

int main()
    boost::random::mt19937 gen;
    boost::random::uniform_real_distribution<> dist(0, 10);

    std::map<int, int> hist;
    for (int n = 0; n < 10000; ++n) {

    for (auto p : hist) {
        std::cout << std::fixed << std::setprecision(1) << std::setw(2)
                  << p.first << ' ' << std::string(p.second/200, '*') << '\n';


If you must use rand() then we can go to the C FAQ for a guides on How can I generate floating-point random numbers? , which basically gives an example similar to this for generating an on the interval [0,1):

#include <stdlib.h>

double randZeroToOne()
    return rand() / (RAND_MAX + 1.);

and to generate a random number in the range from [M,N):

double randMToN(double M, double N)
    return M + (rand() / ( RAND_MAX / (N-M) ) ) ;  

How to get the input from the Tkinter Text Widget?

I did come also in search of how to get input data from the Text widget. Regarding the problem with a new line on the end of the string. You can just use .strip() since it is a Text widget that is always a string.

Also, I'm sharing code where you can see how you can create multiply Text widgets and save them in the dictionary as form data, and then by clicking the submit button get that form data and do whatever you want with it. I hope it helps others. It should work in any 3.x python and probably will work in 2.7 also.

from tkinter import *
from functools import partial

class SimpleTkForm(object):
    def __init__(self):
        self.root = Tk()

    def myform(self):
        self.root.title('My form')
        frame = Frame(self.root, pady=10)
        form_data = dict()
        form_fields = ['username', 'password', 'server name', 'database name']
        cnt = 0
        for form_field in form_fields:
            Label(frame, text=form_field, anchor=NW).grid(row=cnt,column=1, pady=5, padx=(10, 1), sticky="W")
            textbox = Text(frame, height=1, width=15)
            form_data.update({form_field: textbox})
            textbox.grid(row=cnt,column=2, pady=5, padx=(3,20))
            cnt += 1

        conn_test = partial(self.test_db_conn, form_data=form_data)
        Button(frame, text='Submit', width=15, command=conn_test).grid(row=cnt,column=2, pady=5, padx=(3,20))

    def test_db_conn(self, form_data):
        data = {k:v.get('1.0', END).strip() for k,v in form_data.items()}
        # validate data or do anything you want with it

if __name__ == '__main__':
    api = SimpleTkForm()

How do I change the text size in a label widget, python tkinter

Try passing width=200 as additional paramater when creating the Label.

This should work in creating label with specified width.

If you want to change it later, you can use:


As you want to change the size of font itself you can try:

label.config(font=("Courier", 44))

How do you Encrypt and Decrypt a PHP String?

Before you do anything further, seek to understand the difference between encryption and authentication, and why you probably want authenticated encryption rather than just encryption.

To implement authenticated encryption, you want to Encrypt then MAC. The order of encryption and authentication is very important! One of the existing answers to this question made this mistake; as do many cryptography libraries written in PHP.

You should avoid implementing your own cryptography, and instead use a secure library written by and reviewed by cryptography experts.

Update: PHP 7.2 now provides libsodium! For best security, update your systems to use PHP 7.2 or higher and only follow the libsodium advice in this answer.

Use libsodium if you have PECL access (or sodium_compat if you want libsodium without PECL); otherwise...
Use defuse/php-encryption; don't roll your own cryptography!

Both of the libraries linked above make it easy and painless to implement authenticated encryption into your own libraries.

If you still want to write and deploy your own cryptography library, against the conventional wisdom of every cryptography expert on the Internet, these are the steps you would have to take.


  1. Encrypt using AES in CTR mode. You may also use GCM (which removes the need for a separate MAC). Additionally, ChaCha20 and Salsa20 (provided by libsodium) are stream ciphers and do not need special modes.
  2. Unless you chose GCM above, you should authenticate the ciphertext with HMAC-SHA-256 (or, for the stream ciphers, Poly1305 -- most libsodium APIs do this for you). The MAC should cover the IV as well as the ciphertext!


  1. Unless Poly1305 or GCM is used, recalculate the MAC of the ciphertext and compare it with the MAC that was sent using hash_equals(). If it fails, abort.
  2. Decrypt the message.

Other Design Considerations:

  1. Do not compress anything ever. Ciphertext is not compressible; compressing plaintext before encryption can lead to information leaks (e.g. CRIME and BREACH on TLS).
  2. Make sure you use mb_strlen() and mb_substr(), using the '8bit' character set mode to prevent mbstring.func_overload issues.
  3. IVs should be generating using a CSPRNG; If you're using mcrypt_create_iv(), DO NOT USE MCRYPT_RAND!
  4. Unless you're using an AEAD construct, ALWAYS encrypt then MAC!
  5. bin2hex(), base64_encode(), etc. may leak information about your encryption keys via cache timing. Avoid them if possible.

Even if you follow the advice given here, a lot can go wrong with cryptography. Always have a cryptography expert review your implementation. If you are not fortunate enough to be personal friends with a cryptography student at your local university, you can always try the Cryptography Stack Exchange forum for advice.

If you need a professional analysis of your implementation, you can always hire a reputable team of security consultants to review your PHP cryptography code (disclosure: my employer).

Important: When to Not Use Encryption

Don't encrypt passwords. You want to hash them instead, using one of these password-hashing algorithms:

Never use a general-purpose hash function (MD5, SHA256) for password storage.

Don't encrypt URL Parameters. It's the wrong tool for the job.

PHP String Encryption Example with Libsodium

If you are on PHP < 7.2 or otherwise do not have libsodium installed, you can use sodium_compat to accomplish the same result (albeit slower).


 * Encrypt a message
 * @param string $message - message to encrypt
 * @param string $key - encryption key
 * @return string
 * @throws RangeException
function safeEncrypt(string $message, string $key): string
    if (mb_strlen($key, '8bit') !== SODIUM_CRYPTO_SECRETBOX_KEYBYTES) {
        throw new RangeException('Key is not the correct size (must be 32 bytes).');
    $nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
    $cipher = base64_encode(
    return $cipher;

 * Decrypt a message
 * @param string $encrypted - message encrypted with safeEncrypt()
 * @param string $key - encryption key
 * @return string
 * @throws Exception
function safeDecrypt(string $encrypted, string $key): string
    $decoded = base64_decode($encrypted);
    $nonce = mb_substr($decoded, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, '8bit');
    $ciphertext = mb_substr($decoded, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, null, '8bit');
    $plain = sodium_crypto_secretbox_open(
    if (!is_string($plain)) {
        throw new Exception('Invalid MAC');
    return $plain;

Then to test it out:

// This refers to the previous code block.
require "safeCrypto.php"; 

// Do this once then store it somehow:
$message = 'We are all living in a yellow submarine';

$ciphertext = safeEncrypt($message, $key);
$plaintext = safeDecrypt($ciphertext, $key);


Halite - Libsodium Made Easier

One of the projects I've been working on is an encryption library called Halite, which aims to make libsodium easier and more intuitive.

use \ParagonIE\Halite\KeyFactory;
use \ParagonIE\Halite\Symmetric\Crypto as SymmetricCrypto;

// Generate a new random symmetric-key encryption key. You're going to want to store this:
$key = new KeyFactory::generateEncryptionKey();
// To save your encryption key:
KeyFactory::save($key, '/path/to/secret.key');
// To load it again:
$loadedkey = KeyFactory::loadEncryptionKey('/path/to/secret.key');

$message = 'We are all living in a yellow submarine';
$ciphertext = SymmetricCrypto::encrypt($message, $key);
$plaintext = SymmetricCrypto::decrypt($ciphertext, $key);


All of the underlying cryptography is handled by libsodium.

Example with defuse/php-encryption

 * This requires
 * php composer.phar require defuse/php-encryption

use Defuse\Crypto\Crypto;
use Defuse\Crypto\Key;

require "vendor/autoload.php";

// Do this once then store it somehow:
$key = Key::createNewRandomKey();

$message = 'We are all living in a yellow submarine';

$ciphertext = Crypto::encrypt($message, $key);
$plaintext = Crypto::decrypt($ciphertext, $key);


Note: Crypto::encrypt() returns hex-encoded output.

Encryption Key Management

If you're tempted to use a "password", stop right now. You need a random 128-bit encryption key, not a human memorable password.

You can store an encryption key for long-term use like so:

$storeMe = bin2hex($key);

And, on demand, you can retrieve it like so:

$key = hex2bin($storeMe);

I strongly recommend just storing a randomly generated key for long-term use instead of any sort of password as the key (or to derive the key).

If you're using Defuse's library:

"But I really want to use a password."

That's a bad idea, but okay, here's how to do it safely.

First, generate a random key and store it in a constant.

 * Replace this with your own salt! 
 * Use bin2hex() then add \x before every 2 hex characters, like so:
define('MY_PBKDF2_SALT', "\x2d\xb7\x68\x1a\x28\x15\xbe\x06\x33\xa0\x7e\x0e\x8f\x79\xd5\xdf");

Note that you're adding extra work and could just use this constant as the key and save yourself a lot of heartache!

Then use PBKDF2 (like so) to derive a suitable encryption key from your password rather than encrypting with your password directly.

 * Get an AES key from a static password and a secret salt
 * @param string $password Your weak password here
 * @param int $keysize Number of bytes in encryption key
function getKeyFromPassword($password, $keysize = 16)
    return hash_pbkdf2(
        100000, // Number of iterations

Don't just use a 16-character password. Your encryption key will be comically broken.

Java check if boolean is null

The only thing that can be a null is a non-primivite.

A boolean which can only hold TRUE or FALSE is a primitive. The TRUE/FALSE in memory are actually numbers (0 and 1)


1 = TRUE

So when you instantiate an object it will be null String str; // will equal null

On the other hand if you instaniate a primitive it will be assigned to 0 default.

boolean isTrue; // will be 0

int i; // will be 0

ASP.NET MVC: No parameterless constructor defined for this object

I had same problem but later found adding any new interface and corresponding class requires it to be registered under Initializable Module for dependency injection. In my case it was inside code as follows:

public class DependencyResolverInitialization : IConfigurableModule

    public void ConfigureContainer(ServiceConfigurationContext context)
        var structureMapDependencyResolver = new StructureMapDependencyResolver(context.Container);
        GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpControllerActivator), structureMapDependencyResolver);

    private void ConfigureContainer(ConfigurationExpression container)

   public void Initialize(InitializationEngine context)

    public void Uninitialize(InitializationEngine context)

    public void Preload(string[] parameters)


OracleCommand SQL Parameters Binding

You need to use something like this:

 OracleCommand oraCommand = new OracleCommand("SELECT fullname FROM sup_sys.user_profile
                       WHERE domain_user_name = :userName", db);

More can be found in this MSDN article:

It is advised you use the : character instead of @ for Oracle.

Jenkins pipeline how to change to another folder

Use WORKSPACE environment variable to change workspace directory.

If doing using Jenkinsfile, use following code :

    sh "pwd"

Changing color of Twitter bootstrap Nav-Pills

SCSS option for changing all of the buttons...

// do something for each color
@each $color, $value in $theme-colors {

  // nav-link outline colors on the outer nav element
  .nav-outline-#{$color} .nav-link {
    @include button-outline-variant($value);
    margin: 2px 0;

  // nav-link colors on the outer nav element
  .nav-#{$color} .nav-link {
    @include button-variant($value, $value);
    margin: 2px 0;

so you end up with all the defined colors .nav-primary
similar to the .btn-primary...

<div class="col-2 nav-secondary">
            <div class="nav flex-column nav-pills" id="v-pills-tab" role="tablist" aria-orientation="vertical">
                <a class="nav-link" aria-expanded="true" aria-controls="addService" data-toggle="pill" href="#addService" role="tab" aria-selected="false">
                    Add Service
                <a class="nav-link" aria-expanded="true" aria-controls="bonusPayment" data-toggle="pill" href="#bonusPayment" role="tab" aria-selected="false">
                    Bonus Payment
                <a class="nav-link" aria-expanded="true" aria-controls="oneTimeInvoice" data-toggle="pill" href="#oneTimeInvoice" role="tab" aria-selected="false">
                    Invoice - One Time
                <a class="nav-link active" aria-expanded="true" aria-controls="oneTimePayment" data-toggle="pill" href="#oneTimePayment" role="tab" aria-selected="true">
                    Payment - One Time

enter image description here

Could not reliably determine the server's fully qualified domain name

  1. sudo nano /etc/apache2/httpd.conf
  2. search for a text ServerName in nano editor <Ctrl + W>
  3. Insert the following line at the httpd.conf: ServerName localhost
  4. Just restart the Apache: sudo /usr/sbin/apachectl restart

Making macOS Installer Packages which are Developer ID ready

Our example project has two build targets: and We make a component package for each and combine them into a product archive.

A component package contains payload to be installed by the OS X Installer. Although a component package can be installed on its own, it is typically incorporated into a product archive.

Our tools: pkgbuild, productbuild, and pkgutil

After a successful "Build and Archive" open $BUILT_PRODUCTS_DIR in the Terminal.

$ cd ~/Library/Developer/Xcode/DerivedData/.../InstallationBuildProductsLocation
$ pkgbuild --analyze --root ./ HelloWorldAppComponents.plist
$ pkgbuild --analyze --root ./ HelperAppComponents.plist

This give us the component-plist, you find the value description in the "Component Property List" section. pkgbuild -root generates the component packages, if you don't need to change any of the default properties you can omit the --component-plist parameter in the following command.

productbuild --synthesize results in a Distribution Definition.

$ pkgbuild --root ./ \
    --component-plist HelloWorldAppComponents.plist \
$ pkgbuild --root ./ \
    --component-plist HelperAppComponents.plist \
$ productbuild --synthesize \
    --package HelloWorld.pkg --package Helper.pkg \

In the Distribution.xml you can change things like title, background, welcome, readme, license, and so on. You turn your component packages and distribution definition with this command into a product archive:

$ productbuild --distribution ./Distribution.xml \
    --package-path . \

I recommend to take a look at iTunes Installers Distribution.xml to see what is possible. You can extract "Install iTunes.pkg" with:

$ pkgutil --expand "Install iTunes.pkg" "Install iTunes"

Lets put it together

I usually have a folder named Package in my project which includes things like Distribution.xml, component-plists, resources and scripts.

Add a Run Script Build Phase named "Generate Package", which is set to Run script only when installing:

VERSION=$(defaults read "${BUILT_PRODUCTS_DIR}/${FULL_PRODUCT_NAME}/Contents/Info" CFBundleVersion)

PACKAGE_NAME=`echo "$PRODUCT_NAME" | sed "s/ /_/g"`

pkgbuild --root "${INSTALL_ROOT}" \
    --component-plist "./Package/HelloWorldAppComponents.plist" \
    --scripts "./Package/Scripts" \
    --identifier "com.test.pkg.HelloWorld" \
    --version "$VERSION" \
    --install-location "/" \
pkgbuild --root "${BUILT_PRODUCTS_DIR}/" \
    --component-plist "./Package/HelperAppComponents.plist" \
    --identifier "com.test.pkg.Helper" \
    --version "$VERSION" \
    --install-location "/" \
productbuild --distribution "./Package/Distribution.xml"  \
    --package-path "${BUILT_PRODUCTS_DIR}" \
    --resources "./Package/Resources" \

pkgutil --expand "${TMP1_ARCHIVE}" "${TMP2_ARCHIVE}"
# Patches and Workarounds

pkgutil --flatten "${TMP2_ARCHIVE}" "${TMP3_ARCHIVE}"

productsign --sign "Developer ID Installer: John Doe" \

If you don't have to change the package after it's generated with productbuild you could get rid of the pkgutil --expand and pkgutil --flatten steps. Also you could use the --sign paramenter on productbuild instead of running productsign.

Sign an OS X Installer

Packages are signed with the Developer ID Installer certificate which you can download from Developer Certificate Utility.

They signing is done with the --sign "Developer ID Installer: John Doe" parameter of pkgbuild, productbuild or productsign.

Note that if you are going to create a signed product archive using productbuild, there is no reason to sign the component packages.

Developer Certificate Utility

All the way: Copy Package into Xcode Archive

To copy something into the Xcode Archive we can't use the Run Script Build Phase. For this we need to use a Scheme Action.

Edit Scheme and expand Archive. Then click post-actions and add a New Run Script Action:

In Xcode 6:


PACKAGE_NAME=`echo "$PRODUCT_NAME" | sed "s/ /_/g"`

if [ -f "${PKG}" ]; then
    mkdir "${PACKAGES}"
    cp -r "${PKG}" "${PACKAGES}"

In Xcode 5, use this value for PKG instead:


In case your version control doesn't store Xcode Scheme information I suggest to add this as shell script to your project so you can simple restore the action by dragging the script from the workspace into the post-action.


There are two different kinds of scripting: JavaScript in Distribution Definition Files and Shell Scripts.

The best documentation about Shell Scripts I found in WhiteBox - PackageMaker How-to, but read this with caution because it refers to the old package format.

Apple Silicon

In order for the package to run as arm64, the Distribution file has to specify in its hostArchitectures section that it supports arm64 in addition to x86_64:

<options hostArchitectures="arm64,x86_64" />

Additional Reading

Known Issues and Workarounds

Destination Select Pane

The user is presented with the destination select option with only a single choice - "Install for all users of this computer". The option appears visually selected, but the user needs to click on it in order to proceed with the installation, causing some confusion.

Example showing the installer bug

Apples Documentation recommends to use <domains enable_anywhere ... /> but this triggers the new more buggy Destination Select Pane which Apple doesn't use in any of their Packages.

Using the deprecate <options rootVolumeOnly="true" /> give you the old Destination Select Pane. Example showing old Destination Select Pane

You want to install items into the current user’s home folder.

Short answer: DO NOT TRY IT!

Long answer: REALLY; DO NOT TRY IT! Read Installer Problems and Solutions. You know what I did even after reading this? I was stupid enough to try it. Telling myself I'm sure that they fixed the issues in 10.7 or 10.8.

First of all I saw from time to time the above mentioned Destination Select Pane Bug. That should have stopped me, but I ignored it. If you don't want to spend the week after you released your software answering support e-mails that they have to click once the nice blue selection DO NOT use this.

You are now thinking that your users are smart enough to figure the panel out, aren't you? Well here is another thing about home folder installation, THEY DON'T WORK!

I tested it for two weeks on around 10 different machines with different OS versions and what not, and it never failed. So I shipped it. Within an hour of the release I heart back from users who just couldn't install it. The logs hinted to permission issues you are not gonna be able to fix.

So let's repeat it one more time: We do not use the Installer for home folder installations!

RTFD for Welcome, Read-me, License and Conclusion is not accepted by productbuild.

Installer supported since the beginning RTFD files to make pretty Welcome screens with images, but productbuild doesn't accept them.

Workarounds: Use a dummy rtf file and replace it in the package by after productbuild is done.

Note: You can also have Retina images inside the RTFD file. Use multi-image tiff files for this: tiffutil -cat Welcome.tif Welcome_2x.tif -out FinalWelcome.tif. More details.

Starting an application when the installation is done with a BundlePostInstallScriptPath script:



if [ "${COMMAND_LINE_INSTALL}" = "" ]
    /bin/launchctl asuser "${LOGGED_IN_USER_ID}" /usr/bin/open -g PATH_OR_BUNDLE_ID

exit 0

It is important to run the app as logged in user, not as the installer user. This is done with launchctl asuser uid path. Also we only run it when it is not a command line installation, done with installer tool or Apple Remote Desktop.

Javascript + Regex = Nothing to repeat error?

For Google travelers: this stupidly unhelpful error message is also presented when you make a type and double up the + regex operator:



Not okay:


How can I check if character in a string is a letter? (Python)

You can use str.isalpha().

For example:

s = 'a123b'

for char in s:
    print(char, char.isalpha())


a True
1 False
2 False
3 False
b True

XAMPP: Couldn't start Apache (Windows 10)

  • Go to the start menu, and type Turn Windows features on or off
  • Uncheck Internet Information Services
  • Press OK

Is it possible to get element from HashMap by its position?

Use LinkedHashMap:

Hash table and linked list implementation of the Map interface, with predictable iteration order. This implementation differs from HashMap in that it maintains a doubly-linked list running through all of its entries.

in querySelector: how to get the first and get the last elements? what traversal order is used in the dom?

Example to get the last input element:

document.querySelector(".groups-container >div:last-child input")

Open Facebook page from Android app?

For Facebook page:

try {
    intent = new Intent(Intent.ACTION_VIEW, Uri.parse("fb://page/" + pageId));
} catch (Exception e) {
    intent =  new Intent(Intent.ACTION_VIEW, Uri.parse("" + pageId));

For Facebook profile:

try {
    intent = new Intent(Intent.ACTION_VIEW, Uri.parse("fb://profile/" + profileId));
} catch (Exception e) {
    intent =  new Intent(Intent.ACTION_VIEW, Uri.parse("" + profileId));

...because none of the answers points out the difference

Both tested with Facebook v. and Android 5.0.1 on Nexus 4

Leaflet changing Marker color

Try the Leaflet.awesome-markers lib -- it allows you to set colors and other styles.

Best way to combine two or more byte arrays in C#

Concat is the right answer, but for some reason a handrolled thing is getting the most votes. If you like that answer, perhaps you'd like this more general solution even more:

    IEnumerable<byte> Combine(params byte[][] arrays)
        foreach (byte[] a in arrays)
            foreach (byte b in a)
                yield return b;

which would let you do things like:

    byte[] c = Combine(new byte[] { 0, 1, 2 }, new byte[] { 3, 4, 5 }).ToArray();

End of File (EOF) in C

EOF indicates "end of file". A newline (which is what happens when you press enter) isn't the end of a file, it's the end of a line, so a newline doesn't terminate this loop.

The code isn't wrong[*], it just doesn't do what you seem to expect. It reads to the end of the input, but you seem to want to read only to the end of a line.

The value of EOF is -1 because it has to be different from any return value from getchar that is an actual character. So getchar returns any character value as an unsigned char, converted to int, which will therefore be non-negative.

If you're typing at the terminal and you want to provoke an end-of-file, use CTRL-D (unix-style systems) or CTRL-Z (Windows). Then after all the input has been read, getchar() will return EOF, and hence getchar() != EOF will be false, and the loop will terminate.

[*] well, it has undefined behavior if the input is more than LONG_MAX characters due to integer overflow, but we can probably forgive that in a simple example.

Scala how can I count the number of occurrences in a list

scala collections do have count: list.count(_ == 2)

How to add a "confirm delete" option in ASP.Net Gridview?

This should do it.

I found it here:

<asp:TemplateField ShowHeader="False">
        <asp:ImageButton ID="DeleteButton" runat="server" ImageUrl="~/site/img/icons/cross.png"
                    CommandName="Delete" OnClientClick="return confirm('Are you sure you want to delete this event?');"
                    AlternateText="Delete" />               

Dynamically load a JavaScript file

I know my answer is bit late for this question, but, here is a great article in - Deep dive into the murky waters of script loading .

In that article it is concluded that in regards of browser support, the best way to dynamically load JavaScript file without blocking content rendering is the following way:

Considering you've four scripts named script1.js, script2.js, script3.js, script4.js then you can do it with applying async = false:

].forEach(function(src) {
  var script = document.createElement('script');
  script.src = src;
  script.async = false;

Now, Spec says: Download together, execute in order as soon as all download.

Firefox < 3.6, Opera says: I have no idea what this “async” thing is, but it just so happens I execute scripts added via JS in the order they’re added.

Safari 5.0 says: I understand “async”, but don’t understand setting it to “false” with JS. I’ll execute your scripts as soon as they land, in whatever order.

IE < 10 says: No idea about “async”, but there is a workaround using “onreadystatechange”.

Everything else says: I’m your friend, we’re going to do this by the book.

Now, the full code with IE < 10 workaround:

var scripts = [
var src;
var script;
var pendingScripts = [];
var firstScript = document.scripts[0];

// Watch scripts load in IE
function stateChange() {
  // Execute as many scripts in order as we can
  var pendingScript;
  while (pendingScripts[0] && pendingScripts[0].readyState == 'loaded') {
    pendingScript = pendingScripts.shift();
    // avoid future loading events from this script (eg, if src changes)
    pendingScript.onreadystatechange = null;
    // can't just appendChild, old IE bug if element isn't closed
    firstScript.parentNode.insertBefore(pendingScript, firstScript);

// loop through our script urls
while (src = scripts.shift()) {
  if ('async' in firstScript) { // modern browsers
    script = document.createElement('script');
    script.async = false;
    script.src = src;
  else if (firstScript.readyState) { // IE<10
    // create a script and add it to our todo pile
    script = document.createElement('script');
    // listen for state changes
    script.onreadystatechange = stateChange;
    // must set src AFTER adding onreadystatechange listener
    // else we’ll miss the loaded event for cached scripts
    script.src = src;
  else { // fall back to defer
    document.write('<script src="' + src + '" defer></'+'script>');

A few tricks and minification later, it’s 362 bytes

!function(e,t,r){function n(){for(;d[0]&&"loaded"==d[0][f];)c=d.shift(),c[o]=!i.parentNode.insertBefore(c,i)}for(var s,a,c,d=[],i=e.scripts[0],o="onreadystatechange",f="readyState";s=r.shift();)a=e.createElement(t),"async"in i?(a.async=!1,e.head.appendChild(a)):i[f]?(d.push(a),a[o]=n):e.write("<"+t+' src="'+s+'" defer></'+t+">"),a.src=s}(document,"script",[

How to print to console in pytest?

Using -s option will print output of all functions, which may be too much.

If you need particular output, the doc page you mentioned offers few suggestions:

  1. Insert assert False, "dumb assert to make PyTest print my stuff" at the end of your function, and you will see your output due to failed test.

  2. You have special object passed to you by PyTest, and you can write the output into a file to inspect it later, like

    def test_good1(capsys):
        for i in range(5):
            print i
        out, err = capsys.readouterr()
        open("err.txt", "w").write(err)
        open("out.txt", "w").write(out)

    You can open the out and err files in a separate tab and let editor automatically refresh it for you, or do a simple py.test; cat out.txt shell command to run your test.

That is rather hackish way to do stuff, but may be it is the stuff you need: after all, TDD means you mess with stuff and leave it clean and silent when it's ready :-).

Found conflicts between different versions of the same dependent assembly that could not be resolved

I'm using Visual Studio 2017 and encountered this when I updated some Nuget packages. What worked for me was to open my web.config file and find the <runtime><assemblyBinding> node and delete it. Save web.config and rebuild the project.

Look at the Error List window. You'll see what looks like a massively long warning about binding conflicts. Double-click it and it will automatically recreate the <runtime><assemblyBinding> block with the correct mappings.

How to make a simple image upload using Javascript/HTML

<li class="list-group-item active"><h5>Feaured Image</h5></li>
            <li class="list-group-item">
                <div class="input-group mb-3">
                    <div class="custom-file ">
                        <input type="file"  class="custom-file-input" name="thumbnail" id="thumbnail">
                        <label class="custom-file-label" for="thumbnail">Choose file</label>
                <div class="img-thumbnail  text-center">
                    <img src="@if(isset($product)) {{asset('storage/'.$product->thumbnail)}} @else {{asset('images/no-thumbnail.jpeg')}} @endif" id="imgthumbnail" class="img-fluid" alt="">
$('#thumbnail').on('change', function() {
    var file = $(this).get(0).files;
    var reader = new FileReader();
    reader.addEventListener("load", function(e) {
    var image =;
$("#imgthumbnail").attr('src', image);

Create PDF from a list of images

How about this??

from fpdf import FPDF
from PIL import Image
import glob
import os

# set here
image_directory = '/path/to/imageDir'
extensions = ('*.jpg','*.png','*.gif') #add your image extentions
# set 0 if you want to fit pdf to image
# unit : pt
margin = 10

for ext in extensions:

for imagePath in imagelist:
    cover =
    width, height = cover.size

pdf = FPDF(unit="pt", format=[width + 2*margin, height + 2*margin])

pdf.image(imagePath, margin, margin)

destination = os.path.splitext(imagePath)[0]
pdf.output(destination + ".pdf", "F")

Why does Date.parse give incorrect results?

There is some method to the madness. As a general rule, if a browser can interpret a date as an ISO-8601, it will. "2005-07-08" falls into this camp, and so it is parsed as UTC. "Jul 8, 2005" cannot, and so it is parsed in the local time.

See JavaScript and Dates, What a Mess! for more.

How can I change the version of npm using nvm?

By looking at I found there is a way to install a specific version by setting an environment-variable

export npm_install="2.14.14"

Then run the download-script as described at

curl -L | sh

If you omit setting the npm_install variable, then it will install the the version they have marked as latest

How do I free memory in C?

You have to free() the allocated memory in exact reverse order of how it was allocated using malloc().

Note that You should free the memory only after you are done with your usage of the allocated pointers.

memory allocation for 1D arrays:

    buffer = malloc(num_items*sizeof(double));

memory deallocation for 1D arrays:


memory allocation for 2D arrays:

    double **cross_norm=(double**)malloc(150 * sizeof(double *));
    for(i=0; i<150;i++)

memory deallocation for 2D arrays:

    for(i=0; i<150;i++)


Dynamically Add C# Properties at Runtime

Have you taken a look at ExpandoObject?


From MSDN:

The ExpandoObject class enables you to add and delete members of its instances at run time and also to set and get values of these members. This class supports dynamic binding, which enables you to use standard syntax like sampleObject.sampleMember instead of more complex syntax like sampleObject.GetAttribute("sampleMember").

Allowing you to do cool things like:

dynamic dynObject = new ExpandoObject();
dynObject.SomeDynamicProperty = "Hello!";
dynObject.SomeDynamicAction = (msg) =>


Based on your actual code you may be more interested in:

public static dynamic GetDynamicObject(Dictionary<string, object> properties)
    return new MyDynObject(properties);

public sealed class MyDynObject : DynamicObject
    private readonly Dictionary<string, object> _properties;

    public MyDynObject(Dictionary<string, object> properties)
        _properties = properties;

    public override IEnumerable<string> GetDynamicMemberNames()
        return _properties.Keys;

    public override bool TryGetMember(GetMemberBinder binder, out object result)
        if (_properties.ContainsKey(binder.Name))
            result = _properties[binder.Name];
            return true;
            result = null;
            return false;

    public override bool TrySetMember(SetMemberBinder binder, object value)
        if (_properties.ContainsKey(binder.Name))
            _properties[binder.Name] = value;
            return true;
            return false;

That way you just need:

var dyn = GetDynamicObject(new Dictionary<string, object>()
        {"prop1", 12},

dyn.prop1 = 150;

Deriving from DynamicObject allows you to come up with your own strategy for handling these dynamic member requests, beware there be monsters here: the compiler will not be able to verify a lot of your dynamic calls and you won't get intellisense, so just keep that in mind.

C++ template constructor

template<class...>struct types{using type=types;};
template<class T>struct tag{using type=T;};
template<class Tag>using type_t=typename Tag::type;

the above helpers let you work with types as values.

class A {
  template<class T>
  A( tag<T> );

the tag<T> type is a variable with no state besides the type it caries. You can use this to pass a pure-type value into a template function and have the type be deduced by the template function:

auto a = A(tag<int>{});

You can pass in more than one type:

class A {
  template<class T, class U, class V>
  A( types<T,U,V> );
auto a = A(types<int,double,std::string>{});

Elasticsearch : Root mapping definition has unsupported parameters index : not_analyzed

I hope the above answer works for elastic search <7.0 but in 7.0 we cannot specify doc type and it is no longer supported. And in that case if we specify doc type we get similar error.

I you are making use of Elastic search 7.0 and Nest C# lastest version(6.6). There are some breaking changes with ES 7.0 which is causing this issue. This is because we cannot specify doc type and in the version 6.6 of NEST they are using doctype. So in order to solve that untill NEST 7.0 is released, we need to download their beta package

Please go through this link for fixing it

EDIT: NEST 7.0 is now released. NEST 7.0 works with Elastic 7.0. See the release notes here for details.

Proper use cases for Android UserManager.isUserAGoat()?

Android R Update:

From Android R, this method always returns false. Google says that this is done "to protect goat privacy":

 * Used to determine whether the user making this call is subject to
 * teleportations.
 * <p>As of {@link android.os.Build.VERSION_CODES#LOLLIPOP}, this method can
 * now automatically identify goats using advanced goat recognition technology.</p>
 * <p>As of {@link android.os.Build.VERSION_CODES#R}, this method always returns
 * {@code false} in order to protect goat privacy.</p>
 * @return Returns whether the user making this call is a goat.
public boolean isUserAGoat() {
    if (mContext.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.R) {
        return false;
    return mContext.getPackageManager()

Previous answer:

From their source, the method used to return false until it was changed in API 21.

 * Used to determine whether the user making this call is subject to
 * teleportations.
 * @return whether the user making this call is a goat 
public boolean isUserAGoat() {
    return false;

It looks like the method has no real use for us as developers. Someone has previously stated that it might be an Easter egg.

In API 21 the implementation was changed to check if there is an installed app with the package com.coffeestainstudios.goatsimulator

 * Used to determine whether the user making this call is subject to
 * teleportations.
 * <p>As of {@link android.os.Build.VERSION_CODES#LOLLIPOP}, this method can
 * now automatically identify goats using advanced goat recognition technology.</p>
 * @return Returns true if the user making this call is a goat.
public boolean isUserAGoat() {
    return mContext.getPackageManager()

Here is the source and the change.

Finding the handle to a WPF window

Well, instead of passing Application.Current.MainWindow, just pass a reference to whichever window it is you want: new WindowInteropHelper(this).Handle and so on.

With ng-bind-html-unsafe removed, how do I inject HTML?

You indicated that you're using Angular 1.2.0... as one of the other comments indicated, ng-bind-html-unsafe has been deprecated.

Instead, you'll want to do something like this:

<div ng-bind-html="preview_data.preview.embed.htmlSafe"></div>

In your controller, inject the $sce service, and mark the HTML as "trusted":

myApp.controller('myCtrl', ['$scope', '$sce', function($scope, $sce) {
  // ...
  $scope.preview_data.preview.embed.htmlSafe = 

Note that you'll want to be using 1.2.0-rc3 or newer. (They fixed a bug in rc3 that prevented "watchers" from working properly on trusted HTML.)

Operand type clash: uniqueidentifier is incompatible with int

Sounds to me like at least one of those tables has defined UserID as a uniqueidentifier, not an int. Did you check the data in each table? What does SELECT TOP 1 UserID FROM each table yield? An int or a GUID?


I think you have built a procedure based on all tables that contain a column named UserID. I think you should not have included the aspnet_Membership table in your script, since it's not really one of "your" tables.

If you meant to design your tables around the aspnet_Membership database, then why are the rest of the columns int when that table clearly uses a uniqueidentifier for the UserID column?

How to Ping External IP from Java Android

Ping for the google server or any other server

public boolean isConecctedToInternet() {

    Runtime runtime = Runtime.getRuntime();
    try {
        Process ipProcess = runtime.exec("/system/bin/ping -c 1");
        int     exitValue = ipProcess.waitFor();
        return (exitValue == 0);
    } catch (IOException e)          { e.printStackTrace(); }
    catch (InterruptedException e) { e.printStackTrace(); }
    return false;

Codesign error: Provisioning profile cannot be found after deleting expired profile

The solution of Brad Smith worked for me, but I also had to remove the CODE_SIGN_IDENTITY field to make it work.

float:left; vs display:inline; vs display:inline-block; vs display:table-cell;

I prefer inline-block, but float are still useful way to put together HTML elemenets, specially when we have elements which one should stick to the left and one to the right, float working better with writing less lines, while inline-block working well in many other cases.

enter image description here

How to generate auto increment field in select query

here's for SQL server, Oracle, PostgreSQL which support window functions.

SELECT  ROW_NUMBER() OVER (ORDER BY first_name, last_name)  Sequence_no,
FROM    tableName

github changes not staged for commit

For me, I had to commit the subdirectories which had .git in it since both the parent and the subfolder have remotes to push to. And then commit and push the parent directory.

Ubuntu, how do you remove all Python 3 but not 2

Its simple just try: sudo apt-get remove python3.7 or the versions that you want to remove

Converting integer to binary in python

even an easier way

my_num = 6

Check substring exists in a string in C

My own humble (case sensitive) solution:

uint8_t strContains(char* string, char* toFind)
    uint8_t slen = strlen(string);
    uint8_t tFlen = strlen(toFind);
    uint8_t found = 0;

    if( slen >= tFlen )
        for(uint8_t s=0, t=0; s<slen; s++)

                if( string[s] == toFind[t] )
                    if( ++found == tFlen ) return 1;
                else { s -= found; found=0; t=0; }

        return 0;
    else return -1;


strContains("this is my sample example", "th") // 1
strContains("this is my sample example", "sample") // 1
strContains("this is my sample example", "xam") // 1
strContains("this is my sample example", "ple") // 1
strContains("this is my sample example", "ssample") // 0
strContains("this is my sample example", "samplee") // 0
strContains("this is my sample example", "") // 0
strContains("str", "longer sentence") // -1
strContains("ssssssample", "sample") // 1
strContains("sample", "sample") // 1

Tested on ATmega328P (avr8-gnu-toolchain- ;)

How to diff one file to an arbitrary version in Git?

For comparing to 5 commit to the current one, both on master, just simply do:

git diff master~5:pom.xml master:pom.xml

Also you can refer to commit hash number, for example if the hash number is x110bd64, you can do something like this to see the difference:

git diff x110bd64 pom.xml

Request string without GET arguments

Here is a solution that takes into account different ports and https:

$pageURL = (@$_SERVER['HTTPS'] == 'on') ? 'https://' : 'http://';

if ($_SERVER['SERVER_PORT'] != '80')

Or a more basic solution that does not take other ports into account:

$pageURL = (@$_SERVER['HTTPS'] == 'on') ? 'https://' : 'http://';

Use bash to find first folder name that contains a string

You can use the -quit option of find:

find <dir> -maxdepth 1 -type d -name '*foo*' -print -quit

Should I learn C before learning C++?

Learning C forces you to think harder about some issues such as explicit and implicit memory management or storage sizes of basic data types at the time you write your code.

Once you have reached a point where you feel comfortable around C's features and misfeatures, you will probably have less trouble learning and writing in C++.

It is entirely possible that the C++ code you have seen did not look much different from standard C, but that may well be because it was not object oriented and did not use exceptions, object-orientation, templates or other advanced features.

How to deep watch an array in angularjs?

There are performance consequences to deep-diving an object in your $watch. Sometimes (for example, when changes are only pushes and pops), you might want to $watch an easily calculated value, such as array.length.

How to compare objects by multiple fields

With Java 8:

Comparator.comparing((Person p)->p.firstName)

If you have accessor methods:


If a class implements Comparable then such comparator may be used in compareTo method:

public int compareTo(Person o){
    return Comparator.comparing(Person::getFirstName)
              .compare(this, o);

Save bitmap to file function

In kotlin :

private fun File.writeBitmap(bitmap: Bitmap, format: Bitmap.CompressFormat, quality: Int) {
    outputStream().use { out ->
        bitmap.compress(format, quality, out)

usage example:

File(exportDir, "map.png").writeBitmap(bitmap, Bitmap.CompressFormat.PNG, 85)

Hibernate: ids for this class must be manually assigned before calling save()

Assign primary key in hibernate

Make sure that the attribute is primary key and Auto Incrementable in the database. Then map it into the data class with the annotation with @GeneratedValue annotation using IDENTITY.

@Table(name = "client")
data class Client(
        @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "id") private val id: Int? = null



What is the correct way to create a single-instance WPF application?

Named-mutex-based approaches are not cross-platform because named mutexes are not global in Mono. Process-enumeration-based approaches don't have any synchronization and may result in incorrect behavior (e.g. multiple processes started at the same time may all self-terminate depending on timing). Windowing-system-based approaches are not desirable in a console application. This solution, built on top of Divin's answer, addresses all these issues:

using System;
using System.IO;

namespace TestCs
    public class Program
        // The app id must be unique. Generate a new guid for your application. 
        public static string AppId = "01234567-89ab-cdef-0123-456789abcdef";

        // The stream is stored globally to ensure that it won't be disposed before the application terminates.
        public static FileStream UniqueInstanceStream;

        public static int Main(string[] args)

            // Your code here.

            return 0;

        private static void EnsureUniqueInstance()
            // Note: If you want the check to be per-user, use Environment.SpecialFolder.ApplicationData instead.
            string lockDir = Path.Combine(
            string lockPath = Path.Combine(lockDir, $"{AppId}.unique");


                // Create the file with exclusive write access. If this fails, then another process is executing.
                UniqueInstanceStream = File.Open(lockPath, FileMode.Create, FileAccess.Write, FileShare.None);

                // Although only the line above should be sufficient, when debugging with a vshost on Visual Studio
                // (that acts as a proxy), the IO exception isn't passed to the application before a Write is executed.
                UniqueInstanceStream.Write(new byte[] { 0 }, 0, 1);
                throw new Exception("Another instance of the application is already running.");

Maven in Eclipse: step by step installation

I have just include Maven integration plug-in with Eclipse:

Just follow the bellow steps:

In eclipse, from upper menu item select- Help ->click on Install New Software..-> then click on Add button.

set the MavenAPI at name text box and at location text box.

press OK and select the Maven project and install by clicking next.

What does the restrict keyword mean in C++?

This is the original proposal to add this keyword. As dirkgently pointed out though, this is a C99 feature; it has nothing to do with C++.

Git push: "fatal 'origin' does not appear to be a git repository - fatal Could not read from remote repository."

Make sure the config file at .git is correct...Check URL & Make sure your using the correct protocol for your keys ...ProjectWorkspace/.git/config

  ~Wrong url for git@bitbucket
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = true
[remote "origin"]
    url =
    fetch = +refs/heads/*:refs/remotes/origin/*

 ~Wrong URL for SSH...
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = true
    ignorecase = true
    precomposeunicode = true
[remote "origin"]
    fetch = +refs/heads/*:refs/remotes/origin/*
    url = https://[email protected]/emmap1/bitbucketspacestation.git
[branch "master"]
    remote = origin
    merge = refs/heads/master

We are looking at the URL... e.g: For bitbucket, expect [email protected] its make the necessary changes.. SAVE Try pushing again.

UTF-8 text is garbled when form is posted as multipart/form-data

Just use Apache commons upload library. Add URIEncoding="UTF-8" to Tomcat's connector, and use FileItem.getString("UTF-8") instead of FileItem.getString() without charset specified.

Hope this help.

"Cloning" row or column vectors

You can use


tile will generate the reps of the vector

and reshape will give it the shape you want

What is the meaning of Bus: error 10 in C

Let me explain why you do you got this error "Bus error: 10"

char *str1 = "First string";
// for this statement the memory will be allocated into the CODE/TEXT segment which is READ-ONLY

char *str2 = "Second string";
// for this statement the memory will be allocated into the CODE/TEXT segment which is READ-ONLY

strcpy(str1, str2);
// This function will copy the content from str2 into str1, this is not possible because you are try to perform READ WRITE operation inside the READ-ONLY segment.Which was the root cause 

If you want to perform string manipulation use automatic variables(STACK segment) or dynamic variables(HEAP segment)


What is the use of static variable in C#? When to use it? Why can't I declare the static variable inside method?

Static classes don't require you to create an object of that class/instantiate them, you can prefix the C# keyword static in front of the class name, to make it static.

Remember: we're not instantiating the Console class, String class, Array Class.

class Book
    public static int myInt = 0;

public class Exercise
    static void Main()
        Book book = new Book();
       //Use the class name directly to call the property myInt, 
      //don't use the object to access the value of property myInt




C# DateTime to UTC Time without changing the time

Use the DateTime.SpecifyKind static method.

Creates a new DateTime object that has the same number of ticks as the specified DateTime, but is designated as either local time, Coordinated Universal Time (UTC), or neither, as indicated by the specified DateTimeKind value.


DateTime dateTime = DateTime.Now;
DateTime other = DateTime.SpecifyKind(dateTime, DateTimeKind.Utc);

Console.WriteLine(dateTime + " " + dateTime.Kind); // 6/1/2011 4:14:54 PM Local
Console.WriteLine(other + " " + other.Kind);       // 6/1/2011 4:14:54 PM Utc

Java getHours(), getMinutes() and getSeconds()

For a time difference, note that the calendar starts at 01.01.1970, 01:00, not at 00:00. If you're using java.util.Date and java.text.SimpleDateFormat, you will have to compensate for 1 hour:

long start = System.currentTimeMillis();
long end = start + (1*3600 + 23*60 + 45) * 1000 + 678; // 1 h 23 min 45.678 s
Date timeDiff = new Date(end - start - 3600000); // compensate for 1h in millis
SimpleDateFormat timeFormat = new SimpleDateFormat("H:mm:ss.SSS");
System.out.println("Duration: " + timeFormat.format(timeDiff));

This will print:

Duration: 1:23:45.678

Can someone explain Microsoft Unity?

I just watched the 30 minute Unity Dependency Injection IoC Screencast by David Hayden and felt that was a good explaination with examples. Here is a snippet from the show notes:

The screencast shows several common usages of the Unity IoC, such as:

  • Creating Types Not In Container
  • Registering and Resolving TypeMappings
  • Registering and Resolving Named TypeMappings
  • Singletons, LifetimeManagers, and the ContainerControlledLifetimeManager
  • Registering Existing Instances
  • Injecting Dependencies into Existing Instances
  • Populating the UnityContainer via App.config / Web.config
  • Specifying Dependencies via Injection API as opposed to Dependency Attributes
  • Using Nested ( Parent-Child ) Containers

Adjust list style image position?

Or you can use

list-style-position: inside;

MYSQL Truncated incorrect DOUBLE value

I just wasted my time on this and wanted to add an additional case where this error presents itself.

SQL Error (1292): Truncated incorrect DOUBLE value: 'N0003'

Test data

CREATE TABLE `table1 ` (
    `value1` VARCHAR(50) NOT NULL 
INSERT INTO table1 (value1) VALUES ('N0003');

CREATE TABLE `table2 ` (
    `value2` VARCHAR(50) NOT NULL 

INSERT INTO table2 (value2)
SELECT value1
FROM table1
ORDER BY value1+0

The problem is ORDER BY value1+0 - type casting.

I know that it does not answer the question but this is the first result on Google for this error and it should have other examples where this error presents itself.

QuotaExceededError: Dom exception 22: An attempt was made to add something to storage that exceeded the quota

In April 2017 a patch was merged into Safari, so it aligned with the other browsers. This was released with Safari 11.

Right to Left support for Twitter Bootstrap 3

  1. I highly recommend bootstrap-rtl. It is built over Bootstrap core, and rtl support is added as it is a bootstrap theme. This would make your code more maintainable as you can always update your core bootstrap files. CDN

  2. Another option to use this stand-alone library, It also comes with few awesome Arabic fonts.

How to change or add theme to Android Studio?

In Android Studio 3.4.2:

As mentioned in previous answers, you can change theme to Darcula in Appearance & Behavour > Appearance to have default dark theme.

Since macOS Mojave you can use dark mode in system. My issue was the system window bar was still light only for Android Studio:

enter image description here

Note there's an option to change this next to the theme selector: Use dark window headers

enter image description here

Add/remove class with jquery based on vertical scroll?

Add some transition effect to it if you like:,css,js

.clearHeader {

  -webkit-transition: background 2s; /* For Safari 3.1 to 6.0 */
  transition: background 2s;

.clearHeader.darkHeader {

You don't have permission to access / on this server

If you set SELinux in permissive mode (command setenforce 0) and it works (worked for me) then you can run restorecon (sudo restorecon -Rv /var/www/html/) which set the correct context to the files in Apache directory permanently because setenforce is temporal. The context for Apache is httpd_sys_content_t and you can verify it running the command ls -Z /var/www/html/ that outputs something like:

-rwxr-xr-x. root root system_u:object_r:httpd_sys_content_t:s0 index.html

In case the file does not have the right context, appear something like this:

drwxr-xr-x. root root unconfined_u:object_r:user_home_t:s0 tests

Hope it can help you.

PD: excuse me my English

How to make a Bootstrap accordion collapse when clicking the header div?

I've noticed a couple of minor flaws in grim's jsfiddle.

To get the pointer to change to a hand for the whole of the panel use:

.panel-heading {
   cursor: pointer;

I've removed the <a> tag (a style issue) and kept data-toggle="collapse" data-parent="#accordion" data-target="#collapse..." on panel-heading throughout.

I've added a CSS method for displaying chevron, using font-awesome.css in my jsfiddle:

Reading large text files with streams in C#

Have a look at the following code snippet. You have mentioned Most files will be 30-40 MB. This claims to read 180 MB in 1.4 seconds on an Intel Quad Core:

private int _bufferSize = 16384;

private void ReadFile(string filename)
    StringBuilder stringBuilder = new StringBuilder();
    FileStream fileStream = new FileStream(filename, FileMode.Open, FileAccess.Read);

    using (StreamReader streamReader = new StreamReader(fileStream))
        char[] fileContents = new char[_bufferSize];
        int charsRead = streamReader.Read(fileContents, 0, _bufferSize);

        // Can't do much with 0 bytes
        if (charsRead == 0)
            throw new Exception("File is 0 bytes");

        while (charsRead > 0)
            charsRead = streamReader.Read(fileContents, 0, _bufferSize);

Original Article

sql how to cast a select query

If you're using SQL (which you didn't say):

select cast(column as varchar(200)) from table 

You can use it in any statement, for example:

select value where othervalue in( select cast(column as varchar(200)) from table)
from othertable

If you want to do a join query, the answer is here already in another post :)

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

This syntax worked for me in MVC 3 with Razor:

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

open_basedir restriction in effect. File(/) is not within the allowed path(s):

I am using an Apache vhost-File to run PHP with application-specific ini-options on my windows-server. Therefore I use the -d option of the php-command.

I am setting the open_basedir for every application as one of these options.

I needed to set multiple urls as open_basedir, including an UNC-Path, and the syntax for this case was a bit hard to find. You have to seperate the paths with semicolons and if your first path starts with a driveletter you might have to start the list with a semicolon too. At least that's what works for me.


php.exe -d open_basedir=;d:/www/applicationRoot;//internal.unc.path/ressource/

It says that TypeError: document.getElementById(...) is null

It means that element with id passed to getElementById() does not exist.

What's the difference between & and && in MATLAB?

As already mentioned by others, & is a logical AND operator and && is a short-circuit AND operator. They differ in how the operands are evaluated as well as whether or not they operate on arrays or scalars:

  • & (AND operator) and | (OR operator) can operate on arrays in an element-wise fashion.
  • && and || are short-circuit versions for which the second operand is evaluated only when the result is not fully determined by the first operand. These can only operate on scalars, not arrays.

How to count check-boxes using jQuery?

The following code worked for me.


TERM environment variable not set

Using a terminal command i.e. "clear", in a script called from cron (no terminal) will trigger this error message. In your particular script, the smbmount command expects a terminal in which case the work-arounds above are appropriate.

How to generate a random string of 20 characters

Here you go. Just specify the chars you want to allow on the first line.

char[] chars = "abcdefghijklmnopqrstuvwxyz".toCharArray();
StringBuilder sb = new StringBuilder(20);
Random random = new Random();
for (int i = 0; i < 20; i++) {
    char c = chars[random.nextInt(chars.length)];
String output = sb.toString();

If you are using this to generate something sensitive like a password reset URL or session ID cookie or temporary password reset, be sure to use instead. Values produced by java.util.Random and java.util.concurrent.ThreadLocalRandom are mathematically predictable.

How do I use itertools.groupby()?

One useful example that I came across may be helpful:

from itertools import groupby

#user input

myinput = input()

#creating empty list to store output

myoutput = []

for k,g in groupby(myinput):



Sample input: 14445221

Sample output: (1,1) (3,4) (1,5) (2,2) (1,1)

C++ pointer to objects

No you can not do that, MyClass *myclass will define a pointer (memory for the pointer is allocated on stack) which is pointing at a random memory location. Trying to use this pointer will cause undefined behavior.

In C++, you can create objects either on stack or heap like this:

MyClass myClass;

Above will allocate myClass on stack (the term is not there in the standard I think but I am using for clarity). The memory allocated for the object is automatically released when myClass variable goes out of scope.

Other way of allocating memory is to do a new . In that case, you have to take care of releasing the memory by doing delete yourself.

MyClass* p = new MyClass();
delete p;

Remeber the delete part, else there will be memory leak.

I always prefer to use the stack allocated objects whenever possible as I don't have to be bothered about the memory management.

Syntax error "syntax error, unexpected end-of-input, expecting keyword_end (SyntaxError)"

It seems that you have a bunch of describes that never have ends keywords, starting with describe "when email format is invalid" do until describe "when email address is already taken" do

Put an end on those guys and you're probably done =)

How to unescape HTML character entities in Java?

The most reliable way is with

String cleanedString = StringEscapeUtils.unescapeHtml4(originalString);

from org.apache.commons.lang3.StringEscapeUtils.

And to escape the whitespaces

cleanedString = cleanedString.trim();

This will ensure that whitespaces due to copy and paste in web forms to not get persisted in DB.

How to Identify Microsoft Edge browser via CSS?

/* Microsoft Edge Browser 12-18 (All versions before Chromium) */

This one should work:

@supports (-ms-ime-align:auto) {
    .selector {
        property: value;

For more see: Browser Strangeness

How can I convert a DateTime to the number of seconds since 1970?

If the rest of your system is OK with DateTimeOffset instead of DateTime, there's a really convenient feature:

long unixSeconds = DateTimeOffset.Now.ToUnixTimeSeconds();

How to regex in a MySQL query

In my case (Oracle), it's WHERE REGEXP_LIKE(column, 'regex.*'). See here:

SQL Function



This function searches a character column for a pattern. Use this function in the WHERE clause of a query to return rows matching the regular expression you specify.



This function searches for a pattern in a character column and replaces each occurrence of that pattern with the pattern you specify.



This function searches a string for a given occurrence of a regular expression pattern. You specify which occurrence you want to find and the start position to search from. This function returns an integer indicating the position in the string where the match is found.



This function returns the actual substring matching the regular expression pattern you specify.

(Of course, REGEXP_LIKE only matches queries containing the search string, so if you want a complete match, you'll have to use '^$' for a beginning (^) and end ($) match, e.g.: '^regex.*$'.)

How to create a QR code reader in a HTML5 website?

Reader they show at works like a charm, but literaly, you need the one on the webpage, the github version it's really hard to make it work, however, it is possible. The best way to go is reverse-engineer the example shown at the webpage.

However, to edit and get the full potential out of it, it's not so easy. At some point I may post the stripped-down reverse-engineered QR reader, but in the meantime have some fun hacking the code.

Happy coding.

Why does comparing strings using either '==' or 'is' sometimes produce a different result?

If you're not sure what you're doing, use the '=='. If you have a little more knowledge about it you can use 'is' for known objects like 'None'.

Otherwise you'll end up wondering why things doesn't work and why this happens:

>>> a = 1
>>> b = 1
>>> b is a
>>> a = 6000
>>> b = 6000
>>> b is a

I'm not even sure if some things are guaranteed to stay the same between different python versions/implementations.

Difference between Xms and Xmx and XX:MaxPermSize

Java objects reside in an area called the heap, while metadata such as class objects and method objects reside in the permanent generation or Perm Gen area. The permanent generation is not part of the heap.

The heap is created when the JVM starts up and may increase or decrease in size while the application runs. When the heap becomes full, garbage is collected. During the garbage collection objects that are no longer used are cleared, thus making space for new objects.

-Xmssize Specifies the initial heap size.

-Xmxsize Specifies the maximum heap size.

-XX:MaxPermSize=size Sets the maximum permanent generation space size. This option was deprecated in JDK 8, and superseded by the -XX:MaxMetaspaceSize option.

Sizes are expressed in bytes. Append the letter k or K to indicate kilobytes, m or M to indicate megabytes, g or G to indicate gigabytes.


How is the java memory pool divided?

What is perm space?

Java (JVM) Memory Model – Memory Management in Java

Java 7 SE Command Line Options

Java 7 HotSpot VM Options

Programmatically scroll to a specific position in an Android ListView

I have set OnGroupExpandListener and override onGroupExpand() as:

and use setSelectionFromTop() method which Sets the selected item and positions the selection y pixels from the top edge of the ListView. (If in touch mode, the item will not be selected but it will still be positioned appropriately.) (android docs)

    yourlist.setOnGroupExpandListener (new ExpandableListView.OnGroupExpandListener()

        public void onGroupExpand(int groupPosition) {

            expList.setSelectionFromTop(groupPosition, 0);
            //your other code

IIS7 Settings File Locations

It sounds like you're looking for applicationHost.config, which is located in C:\Windows\System32\inetsrv\config.

Yes, it's an XML file, and yes, editing the file by hand will affect the IIS config after a restart. You can think of IIS Manager as a GUI front-end for editing applicationHost.config and web.config.

What is the difference between 'protected' and 'protected internal'?

I have read out very clear definitions for these terms.

Protected : Access is limited to within the class definition and any class that inherits from the class. The type or member can be accessed only by code in the same class or struct or in a class that is derived from that class.

Internal : Access is limited to exclusively to classes defined within the current project assembly. The type or member can be accessed only by code in same class.

Protected-Internal : Access is limited to current assembly or types derived from containing class.

Run Android studio emulator on AMD processor

Recent updates enabled computers with AMD processors to run Android Emulator and you don't need to install ARM images anymore. Taken from the Android Developers blog:

If you have an AMD processor in your computer you need the following setup requirements to be in place:

  • AMD Processor - Recommended: AMD® Ryzen™ processors
  • Android Studio 3.2 Beta or higher
  • Android Emulator v27.3.8+
  • x86 Android Virtual Device (AVD)
  • Windows 10 with April 2018 Update
  • Enable via Windows Features: "Windows Hypervisor Platform"

The important point is enabling Windows Hypervisor Platform and that's it! I strongly recommend reading the whole blog post:

Grant execute permission for a user on all stored procedures in database?

Create a role add this role to users, and then you can grant execute to all the routines in one shot to this role.


This works in SQL Server 2005, I'm not sure about backward compatibility of this feature, I'm sure anything later than 2005 should be fine.

Check array position for null/empty

You can use boost::optional (or std::optional for newer versions), which was developed in particular for decision of your problem:

boost::optional<int> y[50];
geoGraph.y[x] = nums[x];
const size_t size_y = sizeof(y)/sizeof(y[0]); //!!!! correct size of y!!!!
for(int i=0; i<size_y;i++){
   if(y[i]) { //check for null

P.S. Do not use C-type array -> use std::array or std::vector:

std::array<int, 50> y;   //not int y[50] !!!

Character reading from file in Python

Not sure about the (errors="ignore") option but it seems to work for files with strange Unicode characters.

with open(fName, "rb") as fData:
    lines =
    lines = [line.decode("utf-8", errors="ignore") for line in lines]

Select All checkboxes using jQuery

$('#ckbCheckAll').click(function(event) { 
            if($(this).is(":checked")) {

Extract public/private key from PKCS12 file for later use in SSH-PK-Authentication

You can use following commands to extract public/private key from a PKCS#12 container:

  • PKCS#1 Private key

    openssl pkcs12 -in yourP12File.pfx -nocerts -out privateKey.pem
  • Certificates:

    openssl pkcs12 -in yourP12File.pfx -clcerts -nokeys -out publicCert.pem

How to move a file?

os.rename(), shutil.move(), or os.replace()

All employ the same syntax:

import os
import shutil

os.rename("path/to/current/", "path/to/new/destination/for/")
shutil.move("path/to/current/", "path/to/new/destination/for/")
os.replace("path/to/current/", "path/to/new/destination/for/")

Note that you must include the file name ( in both the source and destination arguments. If it is changed, the file will be renamed as well as moved.

Note also that in the first two cases the directory in which the new file is being created must already exist. On Windows, a file with that name must not exist or an exception will be raised, but os.replace() will silently replace a file even in that occurrence.

As has been noted in comments on other answers, shutil.move simply calls os.rename in most cases. However, if the destination is on a different disk than the source, it will instead copy and then delete the source file.

Simple logical operators in Bash

A very portable version (even to legacy bourne shell):

if [ "$varA" = 1 -a \( "$varB" = "t1" -o "$varB" = "t2" \) ]
then    do-something

This has the additional quality of running only one subprocess at most (which is the process [), whatever the shell flavor.

Replace = with -eq if variables contain numeric values, e.g.

  • 3 -eq 03 is true, but
  • 3 = 03 is false. (string comparison)

TypeScript: Interfaces vs Types


My personal convention, which I describe below, is this:

Always prefer interface over type.

When to use type:

  • Use type when defining an alias for primitive types (string, boolean, number, bigint, symbol, etc)
  • Use type when defining tuple types
  • Use type when defining function types
  • Use type when defining a union
  • Use type when trying to overload functions in object types via composition
  • Use type when needing to take advantage of mapped types

When to use interface:

  • Use interface for all object types where using type is not required (see above)
  • Use interface when you want to take advatange of declaration merging.

Primitive types

The easiest difference to see between type and interface is that only type can be used to alias a primitive:

type Nullish = null | undefined;
type Fruit = 'apple' | 'pear' | 'orange';
type Num = number | bigint;

None of these examples are possible to achieve with interfaces.

When providing a type alias for a primitive value, use the type keyword.

Tuple types

Tuples can only be typed via the type keyword:

type row = [colOne: number, colTwo: string];

Use the type keyword when providing types for tuples.

Function types

Functions can be typed by both the type and interface keywords:

// via type
type Sum = (x: number, y: number) => number;

// via interface
interface Sum {
  (x: number, y: number): number;

Since the same effect can be achieved either way, the rule will be to use type in these scenarios since it's a little easier to read (and less verbose).

Use type when defining function types.

Union types

Union types can only be achieved with the type keyword:

type Fruit = 'apple' | 'pear' | 'orange';
type Vegetable = 'broccoli' | 'carrot' | 'lettuce';

// 'apple' | 'pear' | 'orange' | 'broccoli' | 'carrot' | 'lettuce';
type HealthyFoods = Fruit | Vegetable;

When defining union types, use the type keyword

Object types

An object in javascript is a key/value map, and an "object type" is typescript's way of typing those key/value maps. Both interface and type can be used when providing types for an object as the original question makes clear. So when do you use type vs interface for object types?

Intersection vs Inheritance

With types and composition, I can do something like this:

type NumLogger = { 
  log: (val: number) => void;
type StrAndNumLogger = NumLogger & { 
  log: (val: string) => void;

const logger: StrAndNumLogger = {
  log: (val: string | number) => console.log(val)


Typescript is totally happy. What about if I tried that with interfaces:

interface NumLogger { 
    log: (val: number) => void;
interface StrAndNumLogger extends NumLogger { 
    log: (val: string) => void; 

The declaration of StrAndNumLogger gives me an error:

With interfaces, the subtypes have to exactly match the types declared in the super type, otherwise TS will throw an error like the one above.

When trying to overload functions in object types, you'll be better off using the type keyword.

Declaration Merging

The key aspect to interfaces in typescript that distinguish them from types is that they can be extended with new functionality after they've already been declared. A common use case for this feature occurs when you want to extend the types that are exported from a node module. For example, @types/jest exports types that can be used when working with the jest library. However, jest also allows for extending the main jest type with new functions. For example, I can add a custom test like this:

jest.timedTest = async (testName, wrappedTest, timeout) =>
    async () => {
      const start =;
      await wrappedTest(mockTrack);
      const end =;

      console.log(`elapsed time in ms: ${end - start}`);

And then I can use it like this:

test.timedTest('this is my custom test', () => {

And now the time elapsed for that test will be printed to the console once the test is complete. Great! There's only one problem - typescript has no clue that i've added a timedTest function, so it'll throw an error in the editor (the code will run fine, but TS will be angry).

To resolve this, I need to tell TS that there's a new type on top of the existing types that are already available from jest. To do that, I can do this:

declare namespace jest {
  interface It {
    timedTest: (name: string, fn: (mockTrack: Mock) => any, timeout?: number) => void;

Because of how interfaces work, this type declaration will be merged with the type declarations exported from @types/jest. So I didn't just re-declare jest.It; I extended jest.It with a new function so that TS is now aware of my custom test function.

This type of thing is not possible with the type keyword. If @types/jest had declared their types with the type keyword, I wouldn't have been able to extend those types with my own custom types, and therefore there would have been no good way to make TS happy about my new function. This process that is unique to the interface keyword is called declaration merging.

Declaration merging is also possible to do locally like this:

interface Person {
  name: string;

interface Person {
  age: number;

// no error
const person: Person = {
  name: 'Mark',
  age: 25

If I did the exact same thing above with the type keyword, I would have gotten an error since types cannot be re-declared/merged. In the real world, javascript objects are much like this interface example; they can be dynamically updated with new fields at runtime.

Because interface declarations can be merged, interfaces more accurately represent the dynamic nature of javascript objects than types do, and they should be preferred for that reason.

Mapped object types

With the type keyword, I can take advantage of mapped types like this:

type Fruit = 'apple' | 'orange' | 'banana';

type FruitCount = {
  [key in Fruit]: number;

const fruits: FruitCount = {
  apple: 2,
  orange: 3,
  banana: 4

This cannot be done with interfaces:

type Fruit = 'apple' | 'orange' | 'banana';

// ERROR: 
interface FruitCount {
  [key in Fruit]: number;

When needing to take advantage of mapped types, use the type keyword

Rendering raw html with reactjs

dangerouslySetInnerHTML is React’s replacement for using innerHTML in the browser DOM. In general, setting HTML from code is risky because it’s easy to inadvertently expose your users to a cross-site scripting (XSS) attack.

It is better/safer to sanitise your raw HTML (using e.g., DOMPurify) before injecting it into the DOM via dangerouslySetInnerHTML.

DOMPurify - a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMPurify works with a secure default, but offers a lot of configurability and hooks.


import React from 'react'
import createDOMPurify from 'dompurify'
import { JSDOM } from 'jsdom'

const window = (new JSDOM('')).window
const DOMPurify = createDOMPurify(window)

const rawHTML = `
<div class="dropdown">
  <button class="btn btn-default dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-expanded="true">
    <span class="caret"></span>
  <ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu1">
    <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Action</a></li>
    <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Another action</a></li>
    <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Something else here</a></li>
    <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Separated link</a></li>

const YourComponent = () => (
    { <div dangerouslySetInnerHTML={{ __html: DOMPurify.sanitize(rawHTML) }} /> }

export default YourComponent

How do I format axis number format to thousands with a comma in matplotlib?

If you want to original values to be appear in ticks use

plt.xticks(ticks=plt.xticks()[0], labels=plt.xticks()[0])

This will prevent abbreviations like from 3000000 to 1.3 e5 etc. and will show 3000000 (the exact value) in ticks.

Git Clone: Just the files, please?

you can create a shallow clone to only get the last few revisions:

 git clone --depth 1 git://url

then either simply delete the .git directory or use git archive to export your tree.

"The breakpoint will not currently be hit. The source code is different from the original version." What does this mean?

Try disabling and re-setting the breakpoint while running in debug mode instead of doing it before launching debug mode.

Gradle - Could not target platform: 'Java SE 8' using tool chain: 'JDK 7 (1.7)'

For IntelliJ 2019:

Intellij IDEA -> Preferences -> Build, Execution, Deployment -> Build Tools -> Gradle -> Gradle JVM

Select correct version.

PHP Connection failed: SQLSTATE[HY000] [2002] Connection refused

For me was php version from mac instead of MAMP, PATH variable on .bash_profile was wrong. I just prepend the MAMP PHP bin folder to the $PATH env variable. For me was:

  1. In terminal run vim ~/.bash_profile to open ~/.bash_profile

  2. Type i to be able to edit the file, add the bin directory as PATH variable on the top to the file:

    export PATH="/Applications/mampstack-7.1.21-0/php/bin/:$PATH"

  3. Hit ESC, Type :wq, and hit Enter

  4. In Terminal run source ~/.bash_profile
  5. In Terminal type which php, output should be the path to MAMP PHP install.

VBA Count cells in column containing specified value

If you're looking to match non-blank values or empty cells and having difficulty with wildcard character, I found the solution below from here.

Dim n as Integer
n = Worksheets("Sheet1").Range("A:A").Cells.SpecialCells(xlCellTypeConstants).Count

Disabling swap files creation in vim

For anyone trying to set this for Rails projects, add

set directory=tmp,/tmp

into your


So the .swp files will be in their natural location - the tmp directory (per project).

Setting a width and height on an A tag

You need to make your anchor display: block or display: inline-block; and then it will accept the width and height values.

How do I style radio buttons with images - laughing smiley for good, sad smiley for bad?

I have edited one of the previous post. Now, it is way more simple and it works perfectly.

<input style="position: absolute;left:-9999px;" type="radio" name="emotion" id="sad" />
<label for="sad"><img src="red.gif" style="display: inline-block;cursor: pointer;padding: 3px;" alt="I'm sad" /></label>

<input  style="position: absolute;left:-9999px;" type="radio" name="emotion" id="happy" />
<label for="happy"><img src="blue.gif" style="display: inline-block;cursor: pointer;padding: 3px;" alt="I'm happy" /></label>

How to get text with Selenium WebDriver in Python

This is the correct answer. It worked!!

from selenium import webdriver
from import WebDriverWait

driver = webdriver.Chrome("E:\\Python\\selenium\\webdriver\\chromedriver.exe")
print ("Executed Successfully")
driver.find_element_by_xpath("//div[@class='pdp-promo-title pdp-title']").click()
SpecialPrice = driver.find_element_by_xpath("//div[@class='pdp-promo-title pdp-title']").text

How do I find out if the GPS of an Android device is enabled

This method will use the LocationManager service.

Source Link

//Check GPS Status true/false
public static boolean checkGPSStatus(Context context){
    LocationManager manager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE );
    boolean statusOfGPS = manager.isProviderEnabled(LocationManager.GPS_PROVIDER);
    return statusOfGPS;

Where is the Global.asax.cs file?

It don't create normally; you need to add it by yourself.

After adding Global.asax by

  • Right clicking your website -> Add New Item -> Global Application Class -> Add

You need to add a class

  • Right clicking App_Code -> Add New Item -> Class -> name it Global.cs -> Add

Inherit the newly generated by System.Web.HttpApplication and copy all the method created Global.asax to Global.cs and also add an inherit attribute to the Global.asax file.

Your Global.asax will look like this: -

<%@ Application Language="C#" Inherits="Global" %>

Your Global.cs in App_Code will look like this: -

public class Global : System.Web.HttpApplication
    public Global()
        // TODO: Add constructor logic here

    void Application_Start(object sender, EventArgs e)
        // Code that runs on application startup

    /// Many other events like begin request...e.t.c, e.t.c

Using LIKE operator with stored procedure parameters

I was working on same. Check below statement. Worked for me!!

SELECT * FROM [Schema].[Table] WHERE [Column] LIKE '%' + @Parameter + '%'

How to enable scrolling on website that disabled scrolling?

You can paste the following code to the console to scroll up/down using the a/z keyboard keys. If you want to set your own keys you can visit this page to get the keycodes

function KeyPress(e) {
  var evtobj = window.event? event : e
  if (evtobj.keyCode == 90) {
    window.scrollBy(0, 100) 
  if (evtobj.keyCode == 65) {
    window.scrollBy(0, -100) 

document.onkeydown = KeyPress;

How to change default JRE for all Eclipse workspaces?

Finally got it: The way Eclipse picks up the JRE is using the system's PATH.

I did not have C:\home\SFTWR\jdk1.6.0_21\bin in the path at all before and I did have C:\Program Files (x86)\Java\jre6\bin. I had both JRE_HOME and JAVA_HOME set to C:\home\SFTWR\jdk1.6.0_21 but neither of those two mattered. I guess Eclipse did (something to the effect of) where java (or which on UNIX/Linux) to see where Java is in the path and took the JRE to which that java.exe belonged. In my case, despite all the configuration tweaks I had done (including eclipse.ini -vm option as suggested above), it remained stuck to what was in the path.

I removed the old JRE bin from the path, put the new one in, and it works for all workspaces.

Difference between Date(dateString) and new Date(dateString)

Any ideas on how to parse "2010-08-17 12:09:36" with new Date()?

Until ES5, there was no string format that browsers were required to support, though there are a number that are widely supported. However browser support is unreliable an inconsistent, e.g. some will allow out of bounds values and others wont, some support certain formats and others don't, etc.

ES5 introduced support for some ISO 8601 formats, however the OP is not compliant with ISO 8601 and not all browsers in use support it anyway.

The only reliable way is to use a small parsing function. The following parses the format in the OP and also validates the values.

/* Parse date string in format yyyy-mm-dd hh:mm:ss_x000D_
** If string contains out of bounds values, an invalid date is returned_x000D_
** _x000D_
** @param {string} s - string to parse, e.g. "2010-08-17 12:09:36"_x000D_
**                     treated as "local" date and time_x000D_
** @returns {Date}   - Date instance created from parsed string_x000D_
function parseDateString(s) {_x000D_
  var b = s.split(/\D/);_x000D_
  var d = new Date(b[0], --b[1], b[2], b[3], b[4], b[5]);_x000D_
  return d && d.getMonth() == b[1] && d.getHours() == b[3] &&_x000D_
         d.getMinutes() == b[4]? d : new Date(NaN);_x000D_
  parseDateString('2010-08-17 12:09:36') + '<br>' +  // Valid values_x000D_
  parseDateString('2010-08-45 12:09:36')             // Out of bounds date_x000D_

Maintaining href "open in new tab" with an onClick handler in React

Most Secure Solution, JS only

As mentioned by alko989, there is a major security flaw with _blank (details here).

To avoid it from pure JS code:

const openInNewTab = (url) => {
  const newWindow =, '_blank', 'noopener,noreferrer')
  if (newWindow) newWindow.opener = null

Then add to your onClick

onClick={() => openInNewTab('')}

The third param can also take these optional values, based on your needs.

httpd-xampp.conf: How to allow access to an external IP besides localhost?

For Ubuntu xampp,
Go to /opt/lampp/etc/extra/
and open httpd-xampp.conf file and add below lines to get remote access,
    Order allow,deny
    Require all granted
    Allow from all

in /opt/lampp/phpmyadmin section.

And restart lampp using, /opt/lampp/lampp restart

Properly close mongoose's connection once you're done

You can set the connection to a variable then disconnect it when you are done:

var db = mongoose.connect('mongodb://localhost:27017/somedb');

// Do some stuff


Saving a text file on server using JavaScript

It's not possible to save content to the website using only client-side scripting such as JavaScript and jQuery, but by submitting the data in an AJAX POST request you could perform the other half very easily on the server-side.

However, I would not recommend having raw content such as scripts so easily writeable to your hosting as this could easily be exploited. If you want to learn more about AJAX POST requests, you can read the jQuery API page:

And here are some things you ought to be aware of if you still want to save raw script files on your hosting. You have to be very careful with security if you are handling files like this!

File uploading (most of this applies if sending plain text too if javascript can choose the name of the file)

ASP.NET email validator regex

We can use RegularExpressionValidator to validate email address format. You need to specify the regular expression in ValidationExpression property of RegularExpressionValidator. So it will look like

 <asp:RegularExpressionValidator ID="validateEmail"    
  runat="server" ErrorMessage="Invalid email."
  ValidationExpression="^([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$" />

Also in event handler of button or link you need to check !Page.IsValid. Check sample code here : sample code

Also if you don't want to use RegularExpressionValidator you can write simple validate method and in that method usinf RegEx class of System.Text.RegularExpressions namespace.

Check example:


How do I change the default index page in Apache?

You can also set DirectoryIndex in apache's httpd.conf file.

CentOS keeps this file in /etc/httpd/conf/httpd.conf Debian: /etc/apache2/apache2.conf

Open the file in your text editor and find the line starting with DirectoryIndex

To load landing.html as a default (but index.html if that's not found) change this line to read:

DirectoryIndex  landing.html index.html

What's the difference between "Solutions Architect" and "Applications Architect"?

When your title doesn't fit on your business card because you wear too many hats, then someone wordsmiths a nifty title for you.

e.g. Programming/IT/Project Management/Strategy/Business Analyst

Other ways to receive an architect title:

  • You spend more time on the phone and at the whiteboard than you do actually developing working software.
  • You spend more time helping people set up Outlook/Entourage than you do actually developing working software.
  • You're really not that good of a coder to begin with.

How to adjust text font size to fit textview

Here is my solution which works on emulator and phones but not very well on Eclipse layout editor. It's inspired from kilaka's code but the size of the text is not obtained from the Paint but from measuring the TextView itself calling measure(0, 0).

The Java class :

public class FontFitTextView extends TextView
    private static final float THRESHOLD = 0.5f;

    private enum Mode { Width, Height, Both, None }

    private int minTextSize = 1;
    private int maxTextSize = 1000;

    private Mode mode = Mode.None;
    private boolean inComputation;
    private int widthMeasureSpec;
    private int heightMeasureSpec;

    public FontFitTextView(Context context) {

    public FontFitTextView(Context context, AttributeSet attrs) {
            this(context, attrs, 0);

    public FontFitTextView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);

            TypedArray tAttrs = context.obtainStyledAttributes(attrs, R.styleable.FontFitTextView, defStyle, 0);
            maxTextSize = tAttrs.getDimensionPixelSize(R.styleable.FontFitTextView_maxTextSize, maxTextSize);
            minTextSize = tAttrs.getDimensionPixelSize(R.styleable.FontFitTextView_minTextSize, minTextSize);

    private void resizeText() {
            if (getWidth() <= 0 || getHeight() <= 0)
            if(mode == Mode.None)

            final int targetWidth = getWidth();
            final int targetHeight = getHeight();

            inComputation = true;
            float higherSize = maxTextSize;
            float lowerSize = minTextSize;
            float textSize = getTextSize();
            while(higherSize - lowerSize > THRESHOLD) {
                    textSize = (higherSize + lowerSize) / 2;
                    if (isTooBig(textSize, targetWidth, targetHeight)) {
                            higherSize = textSize; 
                    } else {
                            lowerSize = textSize;
            setTextSize(TypedValue.COMPLEX_UNIT_PX, lowerSize);
            measure(widthMeasureSpec, heightMeasureSpec);
            inComputation = false;

    private boolean isTooBig(float textSize, int targetWidth, int targetHeight) {
            setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize);
            measure(0, 0);
            if(mode == Mode.Both)
                    return getMeasuredWidth() >= targetWidth || getMeasuredHeight() >= targetHeight;
            if(mode == Mode.Width)
                    return getMeasuredWidth() >= targetWidth;
                    return getMeasuredHeight() >= targetHeight;

    private Mode getMode(int widthMeasureSpec, int heightMeasureSpec) {
            int widthMode = MeasureSpec.getMode(widthMeasureSpec);
            int heightMode = MeasureSpec.getMode(heightMeasureSpec);
            if(widthMode == MeasureSpec.EXACTLY && heightMode == MeasureSpec.EXACTLY)
                    return Mode.Both;
            if(widthMode == MeasureSpec.EXACTLY)
                    return Mode.Width;
            if(heightMode == MeasureSpec.EXACTLY)
                    return Mode.Height;
            return Mode.None;

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
            if(!inComputation) {
                    this.widthMeasureSpec = widthMeasureSpec;
                    this.heightMeasureSpec = heightMeasureSpec;
                    mode = getMode(widthMeasureSpec, heightMeasureSpec);

    protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) {

    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
            if (w != oldw || h != oldh)

    public int getMinTextSize() {
            return minTextSize;

    public void setMinTextSize(int minTextSize) {
            this.minTextSize = minTextSize;

    public int getMaxTextSize() {
            return maxTextSize;

    public void setMaxTextSize(int maxTextSize) {
            this.maxTextSize = maxTextSize;

The XML attribute file :

    <declare-styleable name="FontFitTextView">
        <attr name="minTextSize" format="dimension" />
        <attr name="maxTextSize" format="dimension" />

Check my github for the latest version of this class. I hope it can be useful for someone. If a bug is found or if the code needs explaination, feel free to open an issue on Github.

Rails filtering array of objects by attribute value

have you tried eager loading?

@attachments = Job.includes(:attachments).find(1).attachments

Div with horizontal scrolling only

overflow-x: scroll;
overflow-y: hidden;


It works for me:

<div style='overflow-x:scroll;overflow-y:hidden;width:250px;height:200px'>
    <div style='width:400px;height:250px'></div>

Joining two table entities in Spring Data JPA

For a typical example of employees owning one or more phones, see this wikibook section.

For your specific example, if you want to do a one-to-one relationship, you should change the next code in ReleaseDateType model:

@Column(nullable = true) 
private Integer media_Id;


@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name="CACHE_MEDIA_ID", nullable=true)
private CacheMedia cacheMedia ;

and in CacheMedia model you need to add:

@OneToOne(cascade=ALL, mappedBy="ReleaseDateType")
private ReleaseDateType releaseDateType;

then in your repository you should replace:

@Query("Select * from A a  left join B b on")
public List<ReleaseDateType> FindAllWithDescriptionQuery();


//In this case a query annotation is not need since spring constructs the query from the method name
public List<ReleaseDateType> findByCacheMedia_Id(Integer id); 

or by:

@Query("FROM ReleaseDateType AS rdt WHERE = ?1")    //This is using a named query method
public List<ReleaseDateType> FindAllWithDescriptionQuery(Integer id);

Or if you prefer to do a @OneToMany and @ManyToOne relation, you should change the next code in ReleaseDateType model:

@Column(nullable = true) 
private Integer media_Id;


@OneToMany(cascade=ALL, mappedBy="ReleaseDateType")
private List<CacheMedia> cacheMedias ;

and in CacheMedia model you need to add:

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name="RELEASE_DATE_TYPE_ID", nullable=true)
private ReleaseDateType releaseDateType;

then in your repository you should replace:

@Query("Select * from A a  left join B b on")
public List<ReleaseDateType> FindAllWithDescriptionQuery();


//In this case a query annotation is not need since spring constructs the query from the method name
public List<ReleaseDateType> findByCacheMedias_Id(Integer id); 

or by:

@Query("FROM ReleaseDateType AS rdt LEFT JOIN rdt.cacheMedias AS cm WHERE = ?1")    //This is using a named query method
public List<ReleaseDateType> FindAllWithDescriptionQuery(Integer id);

Send Email to multiple Recipients with MailMessage?


Just split the incoming address list on the ";" character, and add them to the mail message:

foreach (var address in addresses.Split(new [] {";"}, StringSplitOptions.RemoveEmptyEntries))

In this example, addresses contains "[email protected];[email protected]".

Append to string variable

Ronal, to answer your question in the comment in my answer above:

function wasClicked(str)
  return str+' def';

How do I set default value of select box in angularjs

  <select ng-model="selectedCar" ><option ng-repeat="car in cars "  value="{{car.model}}">{{car.model}}</option></select>
<script>var app = angular.module('myApp', []);app.controller('myCtrl', function($scope) { $ = [{model : "Ford Mustang", color : "red"}, {model : "Fiat 500", color : "white"},{model : "Volvo XC90", color : "black"}];
$scope.selectedCar=$[0].model ;});

How to iterate a table rows with JQuery and access some cell values?

$("tr.item").each(function() {
  $this = $(this);
  var value = $this.find("span.value").html();
  var quantity = $this.find("input.quantity").val();

How do I get a Cron like scheduler in Python?

I don't know if something like that already exists. It would be easy to write your own with time, datetime and/or calendar modules, see

The only concern for a python solution is that your job needs to be always running and possibly be automatically "resurrected" after a reboot, something for which you do need to rely on system dependent solutions.

How to abort an interactive rebase if --abort doesn't work?

Try to follow the advice you see on the screen, and first reset your master's HEAD to the commit it expects.

git update-ref refs/heads/master b918ac16a33881ce00799bea63d9c23bf7022d67

Then, abort the rebase again.

How do you select a particular option in a SELECT element in jQuery?

By value, what worked for me with jQuery 1.7 was the below code, try this:

$('#id option[value=theOptionValue]').prop('selected', 'selected').change();

maven compilation failure

It also matters the order of the dependencies. I've had the same issue. And basically I had to put first the scope test and then scope compile dependencies in the pom.xml. If I put first the scope compile and then the scope test it will fail.

How do I add a newline using printf?

To write a newline use \n not /n the latter is just a slash and a n

Object not found! The requested URL was not found on this server. localhost

One thing I found out is that your folder holding your php/html files cannot be named the same name as the folder in your HTDOCS carrying your project.

What is the meaning of the CascadeType.ALL for a @ManyToOne JPA association

If you just want to delete the address assigned to the user and not to affect on User entity class you should try something like that:

public class User {
   @OneToMany(mappedBy = "addressOwner", cascade = CascadeType.ALL)
   protected Set<Address> userAddresses = new HashSet<>();

public class Addresses {
   @ManyToOne(cascade = CascadeType.REFRESH) @JoinColumn(name = "user_id")
   protected User addressOwner;

This way you dont need to worry about using fetch in annotations. But remember when deleting the User you will also delete connected address to user object.

jQuery Ajax POST example with PHP

Basic usage of .ajax would look something like this:


<form id="foo">
    <label for="bar">A bar</label>
    <input id="bar" name="bar" type="text" value="" />

    <input type="submit" value="Send" />


// Variable to hold request
var request;

// Bind to the submit event of our form

    // Prevent default posting of form - put here to work in case of errors

    // Abort any pending request
    if (request) {
    // setup some local variables
    var $form = $(this);

    // Let's select and cache all the fields
    var $inputs = $form.find("input, select, button, textarea");

    // Serialize the data in the form
    var serializedData = $form.serialize();

    // Let's disable the inputs for the duration of the Ajax request.
    // Note: we disable elements AFTER the form data has been serialized.
    // Disabled form elements will not be serialized.
    $inputs.prop("disabled", true);

    // Fire off the request to /form.php
    request = $.ajax({
        url: "/form.php",
        type: "post",
        data: serializedData

    // Callback handler that will be called on success
    request.done(function (response, textStatus, jqXHR){
        // Log a message to the console
        console.log("Hooray, it worked!");

    // Callback handler that will be called on failure (jqXHR, textStatus, errorThrown){
        // Log the error to the console
            "The following error occurred: "+
            textStatus, errorThrown

    // Callback handler that will be called regardless
    // if the request failed or succeeded
    request.always(function () {
        // Reenable the inputs
        $inputs.prop("disabled", false);


Note: Since jQuery 1.8, .success(), .error() and .complete() are deprecated in favor of .done(), .fail() and .always().

Note: Remember that the above snippet has to be done after DOM ready, so you should put it inside a $(document).ready() handler (or use the $() shorthand).

Tip: You can chain the callback handlers like this: $.ajax().done().fail().always();

PHP (that is, form.php):

// You can access the values posted by jQuery.ajax
// through the global variable $_POST, like this:
$bar = isset($_POST['bar']) ? $_POST['bar'] : null;

Note: Always sanitize posted data, to prevent injections and other malicious code.

You could also use the shorthand .post in place of .ajax in the above JavaScript code:

$.post('/form.php', serializedData, function(response) {
    // Log the response to the console
    console.log("Response: "+response);

Note: The above JavaScript code is made to work with jQuery 1.8 and later, but it should work with previous versions down to jQuery 1.5.

Git push rejected "non-fast-forward"

I had a similar problem and I resolved it with: git pull origin

How to send a POST request in Go?

I know this is old but this answer came up in search results. For the next guy - the proposed and accepted answer works, however the code initially submitted in the question is lower-level than it needs to be. Nobody got time for that.

//one-line post request/response...
response, err := http.PostForm(APIURL, url.Values{
    "ln": {c.ln},
    "ip": {c.ip},
    "ua": {}})

//okay, moving on...
if err != nil {
  //handle postform error

defer response.Body.Close()
body, err := ioutil.ReadAll(response.Body)

if err != nil {
  //handle read response error

fmt.Printf("%s\n", string(body))