Programs & Examples On #Common files


Try using:


This should make the lock exclusive and hold it for the duration of the transaction.

fatal: early EOF fatal: index-pack failed

I got this error when git ran out of memory.

Freeing up some memory (in this case: letting a compile job finish) and trying again worked for me.

SQL: How do I SELECT only the rows with a unique value on certain column?


Getting the inputstream from a classpath resource (XML file)

Some of the "getResourceAsStream()" options in this answer didn't work for me, but this one did:


How to extract the decimal part from a floating point number in C?

Suppose A is your integer then (int)A, means casting the number to an integer and will be the integer part, the other is (A - (int)A)*10^n, here n is the number of decimals to keep.

HTTP Basic Authentication - what's the expected web browser experience?

You might have old invalid username/password cached in your browser. Try clearing them and check again.

If you are using IE and is in your Intranet security zone, IE may be sending your windows credentials automatically.

How do I set a textbox's text to bold at run time?

 txtText.Font = new Font("Segoe UI", 8,FontStyle.Bold);
 //Font(Font Name,Font Size,Font.Style)

Importing files from different folder

In Python 3.4 and later, you can import from a source file directly (link to documentation). This is not the simplest solution, but I'm including this answer for completeness.

Here is an example. First, the file to be imported, named

def announce():

The code that imports the file above, inspired heavily by the example in the documentation:

import importlib.util

def module_from_file(module_name, file_path):
    spec = importlib.util.spec_from_file_location(module_name, file_path)
    module = importlib.util.module_from_spec(spec)
    return module

foo = module_from_file("foo", "/path/to/")

if __name__ == "__main__":

The output:

<module 'foo' from '/path/to/'>
['__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'announce']

Note that the variable name, the module name, and the filename need not match. This code still works:

import importlib.util

def module_from_file(module_name, file_path):
    spec = importlib.util.spec_from_file_location(module_name, file_path)
    module = importlib.util.module_from_spec(spec)
    return module

baz = module_from_file("bar", "/path/to/")

if __name__ == "__main__":

The output:

<module 'bar' from '/path/to/'>
['__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'announce']

Programmatically importing modules was introduced in Python 3.1 and gives you more control over how modules are imported. Refer to the documentation for more information.

Calculate cosine similarity given 2 sentence strings

Well, if you are aware of word embeddings like Glove/Word2Vec/Numberbatch, your job is half done. If not let me explain how this can be tackled. Convert each sentence into word tokens, and represent each of these tokens as vectors of high dimension (using the pre-trained word embeddings, or you could train them yourself even!). So, now you just don't capture their surface similarity but rather extract the meaning of each word which comprise the sentence as a whole. After this calculate their cosine similarity and you are set.

Android - Center TextView Horizontally in LinearLayout



    android:text="HELLO WORLD" />


Why does .json() return a promise?

Why does response.json return a promise?

Because you receive the response as soon as all headers have arrived. Calling .json() gets you another promise for the body of the http response that is yet to be loaded. See also Why is the response object from JavaScript fetch API a promise?.

Why do I get the value if I return the promise from the then handler?

Because that's how promises work. The ability to return promises from the callback and get them adopted is their most relevant feature, it makes them chainable without nesting.

You can use

fetch(url).then(response => 
    response.json().then(data => ({
        data: data,
        status: response.status
).then(res => {

or any other of the approaches to access previous promise results in a .then() chain to get the response status after having awaited the json body.

How to check if ZooKeeper is running or up from command prompt?

enter the below command to verify if zookeeper is running :

echo "ruok" | nc localhost 2181 ; echo 

expected response: imok

jQuery - Check if DOM element already exists

if ($('#some_element').length === 0) {
    //If exists then do manipulations

Adding div element to body or document in JavaScript

You can make your div HTML code and set it directly into body(Or any element) with following code:

var divStr = '<div class="text-warning">Some html</div>';
document.getElementsByTagName('body')[0].innerHTML += divStr;

What does <? php echo ("<pre>"); ..... echo("</pre>"); ?> mean?

The <pre> is used to define pre-formatted text.
The text within <pre> tag is displayed in a fixed-width font and it preserves both spaces and line breaks that are present in the text.
Here I'm printing a JSON FILE without <pre> tag and then with <pre> tag.

Without <pre> tag
With <pre> tag

How to hide/show div tags using JavaScript?

Have you tried

document.getElementById('body').style.display = "none";

instead of

document.getElementById('body').style.display = "hidden";?

How I can check if an object is null in ruby on rails 2?

You can check if an object is nil (null) by calling present? or blank? .


this will return false if the project is an empty string or nil .

or you can use


this is the same as present? with a bang and you can use it if you don't like 'unless'. this will return true for an empty string or nil .

How to use OR condition in a JavaScript IF statement?

here is my example:

 console.log("Too Bad!");   

This says that if the answer is Yes yes or YeS than the same thing will happen

Executing a batch script on Windows shutdown

I found this topic while searching for run script for startup and shutdown Windows 10. Those answers above didn't working. For me on windows 10 worked when I put scripts to task scheduler. How to do this: press window key and write Task scheduler, open it, then on the right is Add task... button. Here you can add scripts. PS: I found action for startup and logout user, there is not for shutdown.

Getting next element while cycling through a list

A rather different way to solve this:

   li = [0,1,2,3]

   for i in range(len(li)):

       if i < len(li)-1:

           # until end is reached
           print 'this', li[i]
           print 'next', li[i+1]


           # end
           print 'this', li[i]

How to set selectedIndex of select element using display text?

<script type="text/javascript">
     function SelectAnimal(){
         //Set selected option of Animals based on AnimalToFind value...
         var animalTofind = document.getElementById('AnimalToFind');
         var selection = document.getElementById('Animals');

        // select element
        for(var i=0;i<selection.options.length;i++){
            if (selection.options[i].innerHTML == animalTofind.value) {
                selection.selectedIndex = i;

setting the selectedIndex property of the select tag will choose the correct item. it is a good idea of instead of comparing the two values (options innerHTML && animal value) you can use the indexOf() method or regular expression to select the correct option despite casing or presense of spaces

selection.options[i].innerHTML.indexOf(animalTofind.value) != -1;

or using .match(/regular expression/)

How to decode Unicode escape sequences like "\u00ed" to proper UTF-8 encoded characters?

$str = '\u0063\u0061\u0074'.'\ud83d\ude38';
$str2 = '\u0063\u0061\u0074'.'\ud83d';

// U+1F638
    "cat\xF0\x9F\x98\xB8" === escape_sequence_decode($str),
    "cat\xEF\xBF\xBD" === escape_sequence_decode($str2)

function escape_sequence_decode($str) {

    // [U+D800 - U+DBFF][U+DC00 - U+DFFF]|[U+0000 - U+FFFF]
    $regex = '/\\\u([dD][89abAB][\da-fA-F]{2})\\\u([dD][c-fC-F][\da-fA-F]{2})

    return preg_replace_callback($regex, function($matches) {

        if (isset($matches[3])) {
            $cp = hexdec($matches[3]);
        } else {
            $lead = hexdec($matches[1]);
            $trail = hexdec($matches[2]);

            $cp = ($lead << 10) + $trail + 0x10000 - (0xD800 << 10) - 0xDC00;

        // Characters between U+D800 and U+DFFF are not allowed in UTF-8
        if ($cp > 0xD7FF && 0xE000 > $cp) {
            $cp = 0xFFFD;

        // php_utf32_utf8(unsigned char *buf, unsigned k)

        if ($cp < 0x80) {
            return chr($cp);
        } else if ($cp < 0xA0) {
            return chr(0xC0 | $cp >> 6).chr(0x80 | $cp & 0x3F);

        return html_entity_decode('&#'.$cp.';');
    }, $str);

jQuery click not working for dynamically created items

Try something like

$("#container").on('click', 'someLinkSelector', function(){ $("#container").html( <new html with new spans> ) });

You basically need to attach your events from a non-dynamic part of the DOM so it can watch for dynamically-created elements.

How to call javascript function from code-behind

One way of doing it is to use the ClientScriptManager:


c - warning: implicit declaration of function ‘printf’

You need to include the appropriate header

#include <stdio.h>

If you're not sure which header a standard function is defined in, the function's man page will state this.

How does one sum only those rows in excel not filtered out?

If you aren't using an auto-filter (i.e. you have manually hidden rows), you will need to use the AGGREGATE function instead of SUBTOTAL.

'invalid value encountered in double_scalars' warning, possibly numpy

Whenever you are working with csv imports, try to use df.dropna() to avoid all such warnings or errors.

How to check if a Docker image with a specific tag exist locally?

I think this functionality should be implemented inside the docker build command (using a flag?), so that it avoids a lot of code duplication.

I used the same condition as the accepted answer inside a wrapper function called docker_build so that it does the necessary checks before calling the original docker build command.

# Usage: docker_build <...> (instead of docker build)

    local arguments=("$@")
    local index
    for (( index=0; index<$#; index++ )); do
        case ${arguments[index]} in
                local tag=${arguments[index+1]}
                if [[ ! -z $(docker images -q "${tag}" 2> /dev/null) ]]; then
                    echo "Image ${tag} already exists."
    command docker build "$@"

Disclaimer: This is not ready for production because it works only with space-separated arguments in long format i.e --tag hello-world:latest. Also, this just modifies the docker build command only, all other commands remain same. If anyone has improvements, please let me know.

I felt like sharing this snippet because the idea of wrapping-standard-commands-in-bash-functions, to avoid code repetition, seemed more elegant and scalable than writing wrapper statements.

Error 'tunneling socket' while executing npm install

Next to what has described @Roshith in his answer here:

If you are behind a proxy, set it correctly in npm.

npm config set proxy http://proxyhost:proxyport
npm config set https-proxy http://proxyhost:proxyport

I had to change also the the file ~.bashrc which also contained a worng proxy setting in my case. I changed those settings here:

export HTTP_PROXY="http://proxyhost:proxyport"
export HTTPS_PROXY="http://proxyhost:proxyport"

Use the following command to verify the proxy settings:

env | grep -i proxy

Fastest way to remove non-numeric characters from a VARCHAR in SQL Server

create function dbo.RemoveNonNumericChar(@str varchar(500))  
returns varchar(500)  
declare @startingIndex int  
set @startingIndex=0  
while 1=1  
    set @startingIndex= patindex('%[^0-9]%',@str)  
    if @startingIndex <> 0  
        set @str = replace(@str,substring(@str,@startingIndex,1),'')  
    else    break;   
return @str  


select dbo.RemoveNonNumericChar('aisdfhoiqwei352345234@#$%^$@345345%^@#$^')  

Connect Android Studio with SVN

In Android Studio we can get the repositories of svn using the VCS->Subversion and the extract the repository and work on the code

Why is it common to put CSRF prevention tokens in cookies?

Using a cookie to provide the CSRF token to the client does not allow a successful attack because the attacker cannot read the value of the cookie and therefore cannot put it where the server-side CSRF validation requires it to be.

The attacker will be able to cause a request to the server with both the auth token cookie and the CSRF cookie in the request headers. But the server is not looking for the CSRF token as a cookie in the request headers, it's looking in the payload of the request. And even if the attacker knows where to put the CSRF token in the payload, they would have to read its value to put it there. But the browser's cross-origin policy prevents reading any cookie value from the target website.

The same logic does not apply to the auth token cookie, because the server is expects it in the request headers and the attacker does not have to do anything special to put it there.

How to clear the logs properly for a Docker container?

sudo find /var/lib/docker/containers/ -type f -name "*.log" -delete

How to programmatically modify WCF app.config endpoint address setting?

For what it's worth, I needed to update the port and scheme for SSL for my RESTFul service. This is what I did. Apologies that it is a bit more that the original question, but hopefully useful to someone.

// Don't forget to add references to System.ServiceModel and System.ServiceModel.Web

using System.ServiceModel;
using System.ServiceModel.Configuration;

var port = 1234;
var isSsl = true;
var scheme = isSsl ? "https" : "http";

var currAssembly = System.Reflection.Assembly.GetExecutingAssembly().CodeBase;
Configuration config = ConfigurationManager.OpenExeConfiguration(currAssembly);

ServiceModelSectionGroup serviceModel = ServiceModelSectionGroup.GetSectionGroup(config);

// Get the first endpoint in services.  This is my RESTful service.
var endp = serviceModel.Services.Services[0].Endpoints[0];

// Assign new values for endpoint
UriBuilder b = new UriBuilder(endp.Address);
b.Port = port;
b.Scheme = scheme;
endp.Address = b.Uri;

// Adjust design time baseaddress endpoint
var baseAddress = serviceModel.Services.Services[0].Host.BaseAddresses[0].BaseAddress;
b = new UriBuilder(baseAddress);
b.Port = port;
b.Scheme = scheme;
serviceModel.Services.Services[0].Host.BaseAddresses[0].BaseAddress = b.Uri.ToString();

// Setup the Transport security
BindingsSection bindings = serviceModel.Bindings;
WebHttpBindingCollectionElement x =(WebHttpBindingCollectionElement)bindings["webHttpBinding"];
WebHttpBindingElement y = (WebHttpBindingElement)x.ConfiguredBindings[0];
var e = y.Security;

e.Mode = isSsl ? WebHttpSecurityMode.Transport : WebHttpSecurityMode.None;
e.Transport.ClientCredentialType = HttpClientCredentialType.None;

// Save changes

CardView Corner Radius

Easiest way to achieve it in Android Studio is explained below:

Step 1:
Write below line in dependencies in build.gradle:

compile ''

Step 2:
Copy below code in your xml file for integrating the CardView.

For cardCornerRadius to work, please be sure to include below line in parent layout: xmlns:card_view=""

And remember to use card_view as namespace for using cardCornerRadius property.

For example : card_view:cardCornerRadius="4dp"

XML Code:

    card_view:cardElevation="3dp" >

        card_view:cardElevation="0dp" >


How does one convert a HashMap to a List in Java?

Basically you should not mess the question with answer, because it is confusing.

Then you could specify what convert mean and pick one of this solution

List<Integer> keyList = Collections.list(Collections.enumeration(map.keySet()));

List<String> valueList = Collections.list(Collections.enumeration(map.values()));

Convert char to int in C and C++

It sort of depends on what you mean by "convert".

If you have a series of characters that represents an integer, like "123456", then there are two typical ways to do that in C: Use a special-purpose conversion like atoi() or strtol(), or the general-purpose sscanf(). C++ (which is really a different language masquerading as an upgrade) adds a third, stringstreams.

If you mean you want the exact bit pattern in one of your int variables to be treated as a char, that's easier. In C the different integer types are really more of a state of mind than actual separate "types". Just start using it where chars are asked for, and you should be OK. You might need an explicit conversion to make the compiler quit whining on occasion, but all that should do is drop any extra bits past 256.

JavaScript property access: dot notation vs. brackets?

Be careful while using these notations: For eg. if we want to access a function present in the parent of a window. In IE :


is not equivalent to


We may either use:




to access it

ImportError: no module named win32api

I had both pywin32 and pipywin32 installed like suggested in previous answer, but I still did not have a folder ${PYTHON_HOME}\Lib\site-packages\win32. This always lead to errors when trying import win32api.

The simple solution was to uninstall both packages and reinstall pywin32:

pip uninstall pipywin32
pip uninstall pywin32
pip install pywin32

Then restart Python (and Jupyter). Now, the win32 folder is there and the import works fine. Problem solved.

What is the difference between declarative and imperative paradigm in programming?

I'll add another example that rarely pops up in declarative/imperative programming discussion: the User Interface!

In C#, you can build an UI using various technologies.

On the imperative end, you could use DirectX or OpenGL to very imperatively draw your buttons, checkboxes, etc... line-by-line (or really, triangle by triangle). It is up to you to say how to draw the user interface.

At the declarative end, you have WPF. You basically write some XML (yeah, yeah, "XAML" technically) and the framework does the work for you. You say what the user interface looks like. It is up to the system to figure out how to do it.

Anyway, just another thing to think about. Just because one language is declarative or imperative does not mean that it doesn't have certain features of the other.

Also, one benefit of declarative programming is that purpose is usually more easily understood from reading the code whereas imperative gives you finer control over execution.

The gist of it all:

Declarative -> what you want done

Imperative -> how you want it done

How to access single elements in a table in R

That is so basic that I am wondering what book you are using to study? Try

data[1, "V1"]  # row first, quoted column name second, and case does matter

Further note: Terminology in discussing R can be crucial and sometimes tricky. Using the term "table" to refer to that structure leaves open the possibility that it was either a 'table'-classed, or a 'matrix'-classed, or a 'data.frame'-classed object. The answer above would succeed with any of them, while @BenBolker's suggestion below would only succeed with a 'data.frame'-classed object.

I am unrepentant in my phrasing despite the recent downvote. There is a ton of free introductory material for beginners in R:

HTML meta tag for content language

As a complement to other answers note that you can also put the lang attribute on various HTML tags inside a page. For example to give a hint to the spellchecker that the input text should be in english:

<input ... spellcheck="true" lang="en"> ...


rsync copy over only certain types of files using include option

One more addition: if you need to sync files by its extensions in one dir only (without of recursion) you should use a construction like this:

rsync -auzv --include './' --include '*.ext' --exclude '*' /source/dir/ /destination/dir/

Pay your attention to the dot in the first --include. --no-r does not work in this construction.


Thanks to for the valuable comment!

Input type DateTime - Value format?

For <input type="datetime" value="" ...

A string representing a global date and time.

Value: A valid date-time as defined in [RFC 3339], with these additional qualifications:

•the literal letters T and Z in the date/time syntax must always be uppercase

•the date-fullyear production is instead defined as four or more digits representing a number greater than 0





This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

The HTML was a control for entering a date and time (hour, minute, second, and fraction of a second) as well as a timezone. This feature has been removed from WHATWG HTML, and is no longer supported in browsers.

Instead, browsers are implementing (and developers are encouraged to use) the datetime-local input type.

Why is HTML5 input type datetime removed from browsers already supporting it?

How to print a Groovy variable in Jenkins?

The following code worked for me:

echo userInput

How to add spacing between columns?

How about just adding a border the same color as the background using css? I'm new to this, so maybe there's a good reason not to, but it looked good when I tried it.

Create two blank lines in Markdown

I tried everything but this worked for me while using Pandoc markdown with TexLive as LaTex engine. In order to add blank lines, you can try adding a blank line but remove ""

## \newline

Just repeat the above, each will add a new blank line

Greater than and less than in one statement

Nowadays you can use lodash:

var x = 1;
var y = 5;
var z = 3;
//results true

Eclipse count lines of code

For static analysis, I've used and recommend SonarQube which runs just about all the metrics you could possibly want on a wide range of languages, and is free in the basic version (you have to pay to analyse the sorts of languages I'd only code in with a gun to my head).

You have to install it as a web-app running the analysis off your source code repository, but it also has an Eclipse plugin.

It's overkill if you just want to know, as a one-off, how many lines of code there are in your project. If you want to track metrics through time, compare across projects, fire warnings when a threshold is exceeded, etc., it's fantastic.

Disclosure: I have no financial relationship with SonarSource.

Powershell: How can I stop errors from being displayed in a script?

Add -ErrorAction SilentlyContinue to your script and you'll be good to go.

How to use ADB in Android Studio to view an SQLite DB

Easiest Way: Connect to Sqlite3 via ADB Shell

I haven't found any way to do that in Android Studio, but I access the db with a remote shell instead of pulling the file each time.

Find all info here:

1- Go to your platform-tools folder in a command prompt

2- Enter the command adb devices to get the list of your devices

C:\Android\adt-bundle-windows-x86_64\sdk\platform-tools>adb devices
List of devices attached
emulator-xxxx   device

3- Connect a shell to your device:

C:\Android\adt-bundle-windows-x86_64\sdk\platform-tools>adb -s emulator-xxxx shell

4a- You can bypass this step on rooted device

run-as <your-package-name> 

4b- Navigate to the folder containing your db file:

cd data/data/<your-package-name>/databases/

5- run sqlite3 to connect to your db:

sqlite3 <your-db-name>.db

6- run sqlite3 commands that you like eg:

Select * from table1 where ...;

Note: Find more commands to run below.

SQLite cheatsheet

There are a few steps to see the tables in an SQLite database:

  1. List the tables in your database:

  2. List how the table looks:

    .schema tablename
  3. Print the entire table:

    SELECT * FROM tablename;
  4. List all of the available SQLite prompt commands:


Add vertical whitespace using Twitter Bootstrap?

For version 3 there doesn't appear to be "bootstrap" way to achieve this neatly.

A panel, a well and a form-group all provide some vertical spacing.

A more formal specific vertical spacing solution is, apparently, on the roadmap for bootstrap v4

Fast way to discover the row count of a table in PostgreSQL

Counting rows in big tables is known to be slow in PostgreSQL. To get a precise number it has to do a full count of rows due to the nature of MVCC. There is a way to speed this up dramatically if the count does not have to be exact like it seems to be in your case.

Instead of getting the exact count (slow with big tables):

SELECT count(*) AS exact_count FROM myschema.mytable;

You get a close estimate like this (extremely fast):

SELECT reltuples::bigint AS estimate FROM pg_class where relname='mytable';

How close the estimate is depends on whether you run ANALYZE enough. It is usually very close.
See the PostgreSQL Wiki FAQ.
Or the dedicated wiki page for count(*) performance.

Better yet

The article in the PostgreSQL Wiki is was a bit sloppy. It ignored the possibility that there can be multiple tables of the same name in one database - in different schemas. To account for that:

SELECT c.reltuples::bigint AS estimate
FROM   pg_class c
JOIN   pg_namespace n ON n.oid = c.relnamespace
WHERE  c.relname = 'mytable'
AND    n.nspname = 'myschema'

Or better still

SELECT reltuples::bigint AS estimate
FROM   pg_class
WHERE  oid = 'myschema.mytable'::regclass;

Faster, simpler, safer, more elegant. See the manual on Object Identifier Types.

Use to_regclass('myschema.mytable') in Postgres 9.4+ to avoid exceptions for invalid table names:

TABLESAMPLE SYSTEM (n) in Postgres 9.5+

SELECT 100 * count(*) AS estimate FROM mytable TABLESAMPLE SYSTEM (1);

Like @a_horse commented, the newly added clause for the SELECT command might be useful if statistics in pg_class are not current enough for some reason. For example:

  • No autovacuum running.
  • Immediately after a big INSERT or DELETE.
  • TEMPORARY tables (which are not covered by autovacuum).

This only looks at a random n % (1 in the example) selection of blocks and counts rows in it. A bigger sample increases the cost and reduces the error, your pick. Accuracy depends on more factors:

  • Distribution of row size. If a given block happens to hold wider than usual rows, the count is lower than usual etc.
  • Dead tuples or a FILLFACTOR occupy space per block. If unevenly distributed across the table, the estimate may be off.
  • General rounding errors.

In most cases the estimate from pg_class will be faster and more accurate.

Answer to actual question

First, I need to know the number of rows in that table, if the total count is greater than some predefined constant,

And whether it ...

... is possible at the moment the count pass my constant value, it will stop the counting (and not wait to finish the counting to inform the row count is greater).

Yes. You can use a subquery with LIMIT:

SELECT count(*) FROM (SELECT 1 FROM token LIMIT 500000) t;

Postgres actually stops counting beyond the given limit, you get an exact and current count for up to n rows (500000 in the example), and n otherwise. Not nearly as fast as the estimate in pg_class, though.

Multiline strings in VB.NET

You could (should?) put the string in a resource-file (e.g. "My Project"/Resources) and then get it with

 Dim a = My.Resources.Whatever_you_chose

Playing sound notifications using Javascript?

Following code might help you to play sound in a web page using javascript only. You can see further details at

function getPlayer(pid) {
    var obj = document.getElementById(pid);
    if (obj.doPlay) return obj;
    for(i=0; i<obj.childNodes.length; i++) {
        var child = obj.childNodes[i];
        if (child.tagName == "EMBED") return child;
function doPlay(fname) {
    var player=getPlayer("audio1");;
function doStop() {
    var player=getPlayer("audio1");

<input type="button" value="Play Sound" onClick="doPlay('texi.wav')">
<a href="#" onClick="doPlay('texi.wav')">[Play]</a>
<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000"
    <embed src="wavplayer.swf?h=20&w=20"

<input type="button" value="Stop Sound" onClick="doStop()">

ViewBag, ViewData and TempData

ViewBag, ViewData, TempData and View State in MVC

ASP.NET MVC offers us three options ViewData, VieBag and TempData for passing data from controller to view and in next request. ViewData and ViewBag are almost similar and TempData performs additional responsibility.

Similarities between ViewBag & ViewData :

Helps to maintain data when you move from controller to view. Used to pass data from controller to corresponding view. Short life means value becomes null when redirection occurs. This is because their goal is to provide a way to communicate between controllers and views. It’s a communication mechanism within the server call.

Difference between ViewBag & ViewData:

ViewData is a dictionary of objects that is derived from ViewDataDictionary class and accessible using strings as keys. ViewBag is a dynamic property that takes advantage of the new dynamic features in C# 4.0. ViewData requires typecasting for complex data type and check for null values to avoid error. ViewBag doesn’t require typecasting for complex data type.

ViewBag & ViewData Example:

public ActionResult Index()

    ViewBag.Name = "Arun Prakash";
    return View();    

public ActionResult Index()  
    ViewData["Name"] = "Arun Prakash";
    return View(); 

In View, we call like below:



Helps to maintain data when you move from one controller to other controller or from one action to other action. In other words when you redirect, “Tempdata” helps to maintain data between those redirects. It internally uses session variables. TempData is meant to be a very short-lived instance, and you should only use it during the current and the subsequent requests only

The only scenario where using TempData will reliably work is when you are redirecting. This is because a redirect kills the current request (and sends HTTP status code 302 Object Moved to the client), then creates a new request on the server to serve the redirected view.

It requires typecasting for complex data type and check for null values to avoid error.

public ActionResult Index()
   var model = new Review()  
      Body = "Start",  

    TempData["ModelName"] = model;    
    return RedirectToAction("About");   

public ActionResult About()       
    var model= TempData["ModelName"];  
    return View(model);   

Convert list into a pandas data frame

You need convert list to numpy array and then reshape:

df = pd.DataFrame(np.array(my_list).reshape(3,3), columns = list("abc"))
print (df)
   a  b  c
0  1  2  3
1  4  5  6
2  7  8  9

How to center an iframe horizontally?

You can put iframe inside a <div>


It works because it is now inside a block element.

iPhone app signing: A valid signing identity matching this profile could not be found in your keychain

After carefully going through the thread here and checking all the solutions proposed by people, I can confidently claim this, after following the steps mentioned on Apple developer docs for creating CSR and mobile provision file, just do this!,

  1. Launch Xcode.
  2. Select window->Organizer
  3. Click this refresh button and that filthy yellow bar will remove instantly.

Trust me, you only have to do this. There is no need to repeat the process again and again to make sure that you doing it the right way. Just press Refresh, enter your login credentials and it's done.

Adding a month to a date in T SQL


will add a month to the column value

How to check for DLL dependency?

On your development machine, you can execute the program and run Sysinternals Process Explorer. In the lower pane, it will show you the loaded DLLs and the current paths to them which is handy for a number of reasons. If you are executing off your deployment package, it would reveal which DLLs are referenced in the wrong path (i.e. weren't packaged correctly).

Currently, our company uses Visual Studio Installer projects to walk the dependency tree and output as loose files the program. In VS2013, this is now an extension: We then package these loose files in a more comprehensive installer but at least that setup project all the dot net dependencies and drops them into the one spot and warns you when things are missing.

LINQ Joining in C# with multiple conditions

Your and should be a && in the where clause.

where epl.DepartAirportAfter >  sd.UTCDepartureTime 
and epl.ArriveAirportBy > sd.UTCArrivalTime

should be

where epl.DepartAirportAfter >  sd.UTCDepartureTime 
&& epl.ArriveAirportBy > sd.UTCArrivalTime

How to create a showdown.js markdown extension

In your last block you have a comma after 'lang', followed immediately with a function. This is not valid json.


It appears that the readme was incorrect. I had to to pass an array with the string 'twitter'.

var converter = new Showdown.converter({extensions: ['twitter']}); converter.makeHtml('whatever @meandave2020'); // output "<p>whatever <a href="">@meandave2020</a></p>" 

I submitted a pull request to update this.

ActionBar text color

A lot of answers are deprecated so I'll update the thread and show how to change text color and backgroundcolor on ActionBar (Toolbar) and in ActionBar pop up menu.

The latest approach in Android (as of May 2018) in working with Action bar (Toolbar) is to use Theme with NoActionBar and use Toolbar instead.

so here is what you need:

  1. In Activity (which extends AppCompatActivity) declare Toolbar:

    Toolbar myToolbar = (Toolbar) findViewById(;
  2. Add Toolbar in the Activity's layout xml. Here we will set our custom (overwritten themes), note android:theme="@style/ThemeOverlay.AppTheme.ActionBar" and app:popupTheme="@style/ThemeOverlay.AppTheme.PopupMenu", they will do the trick.

    app:layout_constraintTop_toTopOf="parent" />
  3. In your styles.xml you will have to overwrite those two styles to set custom colors:

    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="actionBarTheme">@style/ThemeOverlay.AppTheme.ActionBar</item>
    <item name="actionBarPopupTheme">@style/ThemeOverlay.AppTheme.PopupMenu</item>
    <style name="ThemeOverlay.AppTheme.ActionBar" parent="ThemeOverlay.AppCompat.Dark.ActionBar">
    <item name="android:textColorPrimary">@color/action_bar_text_color</item>
    <item name="android:background">@color/action_bar_bg_color</item>
    <style name="ThemeOverlay.AppTheme.PopupMenu" parent="ThemeOverlay.AppCompat.Dark.ActionBar">
    <item name="android:background">@color/popup_bg_color</item>
    <item name="android:textColorPrimary">@color/popup_text_color</item>

That's it folks

p.s. if you ask me I would say: YES, this whole Theme thing is a hell of a mess.

Is it possible to get an Excel document's row count without loading the entire document into memory?

Python 3

import openpyxl as xl

wb = xl.load_workbook("Sample.xlsx", enumerate)

#the 2 lines under do the same. 
sheet = wb.get_sheet_by_name('sheet') 
sheet = wb.worksheets[0]

row_count = sheet.max_row
column_count = sheet.max_column

#this works fore me.

How can I add a Google search box to my website?

No need to embed! Just simply send the user to google and add the var in the search like this: (Remember, code might not work on this, so try in a browser if it doesn't.) Hope it works!

<textarea id="Blah"></textarea><button onclick="search()">Search</button>
function search() {
var Blah = document.getElementById("Blah").value;
location.replace("" + Blah + "");

    function search() {_x000D_
    var Blah = document.getElementById("Blah").value;_x000D_
    location.replace("" + Blah + "");_x000D_
<textarea id="Blah"></textarea><button onclick="search()">Search</button>

Numpy `ValueError: operands could not be broadcast together with shape ...`

If X and beta do not have the same shape as the second term in the rhs of your last line (i.e. nsample), then you will get this type of error. To add an array to a tuple of arrays, they all must be the same shape.

I would recommend looking at the numpy broadcasting rules.

How to add a scrollbar to an HTML5 table?

you can try this


          #table-wrapper {
          #table-wrapper table {
          #table-wrapper table thead th .text {
                  border:1px solid red;


<div id="table-wrapper">

                <th><span class="text">album</span></th>
                <th><span class="text">song</span></th>
                <th><span class="text">genre</span></th>
<tr> <td> album 0</td> <td> song0</td> <td> genre0</td> </tr>
<tr> <td>album 1</td> <td>song 1</td> <td> genre1</td> </tr>
<tr> <td> album2</td> <td>song 2</td> <td> genre2</td> </tr>
<tr> <td> album3</td> <td>song 3</td> <td> genre3</td> </tr>
<tr> <td> album4</td> <td>song 4</td> <td>genre 4</td> </tr>
<tr> <td> album5</td> <td>song 5</td> <td>genre 5</td> </tr>
<tr> <td>album 6</td> <td> song6</td> <td> genre6</td> </tr>
<tr> <td>album 7</td> <td> song7</td> <td> genre7</td> </tr>
<tr> <td> album8</td> <td> song8</td> <td>genre 8</td> </tr>
<tr> <td> album9</td> <td> song9</td> <td> genre9</td> </tr>
<tr> <td> album10</td> <td>song 10</td> <td> genre10</td> </tr>
<tr> <td> album11</td> <td>song 11</td> <td> genre11</td> </tr>
<tr> <td> album12</td> <td> song12</td> <td> genre12</td> </tr>
<tr> <td>album 13</td> <td> song13</td> <td> genre13</td> </tr>
<tr> <td> album14</td> <td> song14</td> <td> genre14</td> </tr>
<tr> <td> album15</td> <td> song15</td> <td> genre15</td> </tr>
<tr> <td>album 16</td> <td> song16</td> <td> genre16</td> </tr>
<tr> <td>album 17</td> <td> song17</td> <td> genre17</td> </tr>
<tr> <td> album18</td> <td> song18</td> <td> genre18</td> </tr>
<tr> <td> album19</td> <td> song19</td> <td> genre19</td> </tr>
<tr> <td> album20</td> <td> song20</td> <td> genre20</td> </tr>    

Check this fiddle :

this will keep the table head fixed ,and scroll only the table content .

How are Anonymous inner classes used in Java?

One more advantage:
As you know that Java doesn't support multiple inheritance, so if you use "Thread" kinda class as anonymous class then the class still has one space left for any other class to extend.

Return a value of '1' a referenced cell is empty

You may have to use =IF(ISNUMBER(A1),A1,1) in some situations where you are looking for number values in cell.

package does not exist ; in Android studio 0.8

error: package does not exist import;

using jetify helped to solve .

from jcesarmobile' s post --- >

Error: "package* does not exist" This error occurs when some Cordova or Capacitor plugin has old android support dependencies instead of using the new AndroidX equivalent. You should report the issue in the plugin repository so the maintainers can update the plugin to use AndroidX dependencies.

As workaround you can also patch the plugin using jetifier

npm install jetifier

npx jetify

npx cap sync android

How can I turn a JSONArray into a JSONObject?

I have JSONObject like this: {"status":[{"Response":"success"}]}.

If I want to convert the JSONObject value, which is a JSONArray into JSONObject automatically without using any static value, here is the code for that.

JSONArray array=new JSONArray();
JSONObject obj2=new JSONObject();
obj2.put("Response", "success");
JSONObject obj=new JSONObject();

Converting the JSONArray to JSON Object:

Iterator<String> it=obj.keys();
JSONObject innerJson=new JSONObject(obj.toString());
JSONArray innerArray=innerJson.getJSONArray(keys);
for(int i=0;i<innerArray.length();i++){
JSONObject innInnerObj=innerArray.getJSONObject(i);
Iterator<String> InnerIterator=innInnerObj.keys();
System.out.println("InnInnerObject value is :"+innInnerObj.get(;


What does Visual Studio mean by normalize inconsistent line endings?

What that usually means is that you have lines ending with something other than a carriage return/line feed pair. It often happens when you copy and paste from a web page into the code editor.

Normalizing the line endings is just making sure that all of the line ending characters are consistent. It prevents one line from ending in \r\n and another ending with \r or \n; the first is the Windows line end pair, while the others are typically used for Mac or Linux files.

Since you're developing in Visual Studio, you'll obviously want to choose "Windows" from the drop down. :-)

How to increment a number by 2 in a PHP For Loop

Another simple solution with +=:

$y = 1;

for ($x = $y; $x <= 15; $y++) {
  printf("The number of first paragraph is: $y <br>");
  printf("The number of second paragraph is: $x+=2 <br>");

Freeing up a TCP/IP port?

To check all ports:

netstat -lnp

To close an open port:

fuser -k port_no/tcp


fuser -k 8080/tcp

In both cases you can use the sudo command if needed.

How do I add slashes to a string in Javascript?

var myNewString = myOldString.replace(/'/g, "\\'");

no operator "<<" matches these operands

You're not including the standard <string> header.

You got [un]lucky that some of its pertinent definitions were accidentally made available by the other standard headers that you did include ... but operator<< was not.

Why does Boolean.ToString output "True" and not "true"

Only people from Microsoft can really answer that question. However, I'd like to offer some fun facts about it ;)

First, this is what it says in MSDN about the Boolean.ToString() method:

Return Value

Type: System.String

TrueString if the value of this instance is true, or FalseString if the value of this instance is false.


This method returns the constants "True" or "False". Note that XML is case-sensitive, and that the XML specification recognizes "true" and "false" as the valid set of Boolean values. If the String object returned by the ToString() method is to be written to an XML file, its String.ToLower method should be called first to convert it to lowercase.

Here comes the fun fact #1: it doesn't return TrueString or FalseString at all. It uses hardcoded literals "True" and "False". Wouldn't do you any good if it used the fields, because they're marked as readonly, so there's no changing them.

The alternative method, Boolean.ToString(IFormatProvider) is even funnier:


The provider parameter is reserved. It does not participate in the execution of this method. This means that the Boolean.ToString(IFormatProvider) method, unlike most methods with a provider parameter, does not reflect culture-specific settings.

What's the solution? Depends on what exactly you're trying to do. Whatever it is, I bet it will require a hack ;)

Favicon not showing up in Google Chrome

I also experienced the same thing. I found out that my favicon.ico had not been processed as a legitimate shortcut icon. I understand that favicons must be scaled to 16x16 and follow the Microsoft Icon format.

Open Source Javascript PDF viewer

There is an open source HTML5/javascript reader available called Trapeze though its still in its early stages.

Demo site:

Github page:

Disclaimer: I'm the author.

C# how to convert File.ReadLines into string array?

string[] lines = File.ReadLines("c:\\file.txt").ToArray();

Although one wonders why you'll want to do that when ReadAllLines works just fine.

Or perhaps you just want to enumerate with the return value of File.ReadLines:

var lines = File.ReadAllLines("c:\\file.txt");
foreach (var line in lines)
    Console.WriteLine("\t" + line);

How to convert NUM to INT in R?

You can use convert from hablar to change a column of the data frame quickly.


x <- tibble(var = c(1.34, 4.45, 6.98))

x %>% 

gives you:

# A tibble: 3 x 1
1     1
2     4
3     6

Determine the size of an InputStream

I just wanted to add, Apache Commons IO has stream support utilities to perform the copy. (Btw, what do you mean by placing the file into an inputstream? Can you show us your code?)


Okay, what do you want to do with the contents of the item? There is an item.get() which returns the entire thing in a byte array.


item.getSize() will return the uploaded file size.

Why is my CSS bundling not working with a bin deployed MVC4 app?

Just to clarify a few things, System.Web.Optimization (aka Bundling/Minification) will work against 4.0. It is not depending on anything in 4.5, so there should be no problems there.

If script bundling is working, and its only an issue with CSS, perhaps the issue is with relative URLs?

I'd first look at the rendered page and see if you are getting references to the CSS bundle, i.e. something like:

<link href="/app/Content/css?v=oI5uNwN5NWmYrn8EXEybCI" rel="stylesheet"/>

If you are, then bundling is working, but something inside your CSS bundle is messed up. Usually this is due to relative URLs inside your CSS bundle being incorrect, i.e. if your images live under ~/Content, but you name your bundle ~/bundles/css, the browser will incorrectly look for images under ~/bundles.

Also, the default behavior is to disable bundling and minification when debug=true. So, if you do want optimizations enabled even when debug=true, you will need to force:

BundleTable.EnableOptimizations = true

Updated: With the new info that v="", that means the bundle was empty, you should verify that you are adding files to the bundle correctly, and that it found them. How are you including files to the bundle?

How to find rows that have a value that contains a lowercase letter

I have to add BINARY to the ColumnX, to get result as case sensitive


ERROR:'keytool' is not recognized as an internal or external command, operable program or batch file

Check that the directory the keytool executable is in is on your %PATH% environment variable.

For example, on my Windows 7 machine, it is in C:\Program Files (x86)\Java\jre6\bin, and my %PATH% variable looks like C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Program Files (x86)\Java\jre6\bin;C:\WINDOWS\System32\WindowsPowerShell\v1.0\ (and many other entries)

Hide axis and gridlines Highcharts

If you have bigger version than v4.9 of Highcharts you can use visible: false in the xAxis and yAxis settings.



    chart: {
        type: 'column'

    title: {
        text: 'Highcharts axis visibility'

    xAxis: {
        visible: false

    yAxis: {
        title: {
            text: 'Fruit'
        visible: false


How do I load an org.w3c.dom.Document from XML in a string?

To manipulate XML in Java, I always tend to use the Transformer API:

import javax.xml.transform.Source;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMResult;

public static Document loadXMLFrom(String xml) throws TransformerException {
    Source source = new StreamSource(new StringReader(xml));
    DOMResult result = new DOMResult();
    TransformerFactory.newInstance().newTransformer().transform(source , result);
    return (Document) result.getNode();

Function to check if a string is a date

Although this has an accepted answer, it is not going to effectively work in all cases. For example, I test date validation on a form field I have using the date "10/38/2013", and I got a valid DateObject returned, but the date was what PHP call "overflowed", so that "10/38/2013" becomes "11/07/2013". Makes sense, but should we just accept the reformed date, or force users to input the correct date? For those of us who are form validation nazis, We can use this dirty fix: and just return false when the object throws this warning.

The other workaround would be to match the string date to the formatted one, and compare the two for equal value. This seems just as messy. Oh well. Such is the nature of PHP dev.

Passing data through intent using Serializable

1- You are using which doesn't implements Serializable class so you have to remove that class then it will work.

2- for brief you can visit how to pass data between intents.

Android set bitmap to Imageview

There is a library named Picasso which can efficiently load images from a URL. It can also load an image from a file.


  1. Load URL into ImageView without generating a bitmap:

    Picasso.with(context) // Context
           .load("") // URL or file
           .into(imageView); // An ImageView object to show the loaded image
  2. Load URL into ImageView by generating a bitmap:

           .into(new Target() {
               public void onBitmapLoaded(final Bitmap bitmap, Picasso.LoadedFrom from) {
                   /* Save the bitmap or do something with it here */
                   // Set it in the ImageView
               public void onBitmapFailed(Drawable errorDrawable) {
               public void onPrepareLoad(Drawable placeHolderDrawable) {

There are many more options available in Picasso. Here is the documentation.

How to use BeginInvoke C#

I guess your code relates to Windows Forms.
You call BeginInvoke if you need something to be executed asynchronously in the UI thread: change control's properties in most of the cases.
Roughly speaking this is accomplished be passing the delegate to some procedure which is being periodically executed. (message loop processing and the stuff like that)

If BeginInvoke is called for Delegate type the delegate is just invoked asynchronously.
(Invoke for the sync version.)

If you want more universal code which works perfectly for WPF and WinForms you can consider Task Parallel Library and running the Task with the according context. (TaskScheduler.FromCurrentSynchronizationContext())

And to add a little to already said by others: Lambdas can be treated either as anonymous methods or expressions.
And that is why you cannot just use var with lambdas: compiler needs a hint.


this requires .Net v4.0 and higher

// This line must be called in UI thread to get correct scheduler
var scheduler = System.Threading.Tasks.TaskScheduler.FromCurrentSynchronizationContext();

// this can be called anywhere
var task = new System.Threading.Tasks.Task( () => someformobj.listBox1.SelectedIndex = 0);

// also can be called anywhere. Task  will be scheduled for execution.
// And *IF I'm not mistaken* can be (or even will be executed synchronously)
// if this call is made from GUI thread. (to be checked) 

If you started the task from other thread and need to wait for its completition task.Wait() will block calling thread till the end of the task.

Read more about tasks here.

How to convert .pfx file to keystore with private key?

If you work with JDK 1.5 or below the keytool utility will not have the -importkeystore option (see JDK 1.5 keytool documentation) and the solution by MikeD will be available only by transferring the .pfx on a machine with a newer JDK (1.6 or above).

Another option in JDK 1.5 or below (if you have Oracle WebLogic product), is to follow the instructions from this Oracle document: Using PFX and PEM Certificate Formats with Keystores. It describes the conversion into .pem format, how to extract certificates information from this textual format, and import it into .jks format with java utils.ImportPrivateKey utility (this is an utility included with WebLogic product).

Create JPA EntityManager without persistence.xml configuration file

Is there a way to initialize the EntityManager without a persistence unit defined?

You should define at least one persistence unit in the persistence.xml deployment descriptor.

Can you give all the required properties to create an Entitymanager?

  • The name attribute is required. The other attributes and elements are optional. (JPA specification). So this should be more or less your minimal persistence.xml file:
    <persistence-unit name="[REQUIRED_PERSISTENCE_UNIT_NAME_GOES_HERE]">

In Java EE environments, the jta-data-source and non-jta-data-source elements are used to specify the global JNDI name of the JTA and/or non-JTA data source to be used by the persistence provider.

So if your target Application Server supports JTA (JBoss, Websphere, GlassFish), your persistence.xml looks like:

    <persistence-unit name="[REQUIRED_PERSISTENCE_UNIT_NAME_GOES_HERE]">

If your target Application Server does not support JTA (Tomcat), your persistence.xml looks like:

    <persistence-unit name="[REQUIRED_PERSISTENCE_UNIT_NAME_GOES_HERE]">

If your data source is not bound to a global JNDI (for instance, outside a Java EE container), so you would usually define JPA provider, driver, url, user and password properties. But property name depends on the JPA provider. So, for Hibernate as JPA provider, your persistence.xml file will looks like:

    <persistence-unit name="[REQUIRED_PERSISTENCE_UNIT_NAME_GOES_HERE]">
            <property name="hibernate.connection.driver_class" value="org.apache.derby.jdbc.ClientDriver"/>
            <property name="hibernate.connection.url" value="jdbc:derby://localhost:1527/EmpServDB;create=true"/>
            <property name="hibernate.connection.username" value="APP"/>
            <property name="hibernate.connection.password" value="APP"/>

Transaction Type Attribute

In general, in Java EE environments, a transaction-type of RESOURCE_LOCAL assumes that a non-JTA datasource will be provided. In a Java EE environment, if this element is not specified, the default is JTA. In a Java SE environment, if this element is not specified, a default of RESOURCE_LOCAL may be assumed.

  • To insure the portability of a Java SE application, it is necessary to explicitly list the managed persistence classes that are included in the persistence unit (JPA specification)

I need to create the EntityManager from the user's specified values at runtime

So use this:

Map addedOrOverridenProperties = new HashMap();

// Let's suppose we are using Hibernate as JPA provider
addedOrOverridenProperties.put("hibernate.show_sql", true);

Persistence.createEntityManagerFactory(<PERSISTENCE_UNIT_NAME_GOES_HERE>, addedOrOverridenProperties);

How to select true/false based on column value?

Maybe too late, but I'd cast 0/1 as bit to make the datatype eventually becomes True/False when consumed by .NET framework:

SELECT   EntityId, 
            WHEN EntityProfileIs IS NULL 
            THEN CAST(0 as bit) 
            ELSE CAST(1 as bit) END AS HasProfile
FROM      Entities
LEFT JOIN EntityProfiles ON EntityProfiles.EntityId = Entities.EntityId`

How to include multiple js files using jQuery $.getScript() method

Append scripts with async=false

Here's a different, but super simple approach. To load multiple scripts you can simply append them to body.

  • Loads them asynchronously, because that's how browsers optimize the page loading
  • Executes scripts in order, because that's how browsers parse the HTML tags
  • No need for callback, because scripts are executed in order. Simply add another script, and it will be executed after the other scripts

More info here:

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

Count the items from a IEnumerable<T> without iterating?

No, not in general. One point in using enumerables is that the actual set of objects in the enumeration is not known (in advance, or even at all).

number of values in a list greater than a certain number

You can do like this using function:

l = [34,56,78,2,3,5,6,8,45,6]  
print ("The list : " + str(l))   
def count_greater30(l):  
    count = 0  
    for i in l:  
        if i > 30:  
            count = count + 1.  
    return count
print("Count greater than 30 is : " + str(count)).  

How do I install the yaml package for Python?

Use strictyaml instead

If you have the luxury of creating the yaml file yourself, or if you don't require any of these features of regular yaml, I recommend using strictyaml instead of the standard pyyaml package.

In short, default yaml has some serious flaws in terms of security, interface, and predictability. strictyaml is a subset of the yaml spec that does not have those issues (and is better documented).

You can read more about the problems with regular yaml here

OPINION: strictyaml should be the default implementation of yaml and the old yaml spec should be obsoleted.

Can I use a binary literal in C or C++?

template<unsigned long N>
struct bin {
    enum { value = (N%10)+2*bin<N/10>::value };
} ;

struct bin<0> {
    enum { value = 0 };
} ;

// ...
    std::cout << bin<1000>::value << '\n';

The leftmost digit of the literal still has to be 1, but nonetheless.

node and Error: EMFILE, too many open files

This will probably fix your problem if you're struggling to deploy a React solution that was created with the Visual Studio template (and has a web.config). In Azure Release Pipelines, when selecting the template, use:

Azure App Service deployment

Instead of:

Deploy a Node.js app to Azure App Service

It worked for me!

Get full path of a file with FileUpload Control

This dumps the file in your temp folder with file name, then after that you can call it and not worry about it. Because it will get deleted if it is in your temp folder for an amount of days.

string filename = Path.Combine(Path.GetTempPath(), Path.ChangeExtension(Guid.NewGuid().ToString(),".xls"));
                File.WriteAllBytes(filename, FileUploadControl.FileBytes);

jQuery .on('change', function() {} not triggering for dynamically created inputs

$(document).on('change', '#id', aFunc);

function aFunc() {
  // code here...

Markdown and image alignment

Even cleaner would be to just put p#given img { float: right } in the style sheet, or in the <head> and wrapped in style tags. Then, just use the markdown ![Alt text](/path/to/img.jpg).

Optimistic vs. Pessimistic locking

In most cases, optimistic locking is more efficient and offers higher performance. When choosing between pessimistic and optimistic locking, consider the following:

  • Pessimistic locking is useful if there are a lot of updates and relatively high chances of users trying to update data at the same time. For example, if each operation can update a large number of records at a time (the bank might add interest earnings to every account at the end of each month), and two applications are running such operations at the same time, they will have conflicts.

  • Pessimistic locking is also more appropriate in applications that contain small tables that are frequently updated. In the case of these so-called hotspots, conflicts are so probable that optimistic locking wastes effort in rolling back conflicting transactions.

  • Optimistic locking is useful if the possibility for conflicts is very low – there are many records but relatively few users, or very few updates and mostly read-type operations.

Trigger validation of all fields in Angular Form submit

I done something following to make it work.

<form name="form" name="plantRegistrationForm">
  <div ng-class="{ 'has-error': (form.$submitted || form.headerName.$touched) && form.headerName.$invalid }">
    <div class="col-md-3">
      <div class="label-color">HEADER NAME 
        <span class="red"><strong>*</strong></span></div>
    <div class="col-md-9">
      <input type="text" name="headerName" id="headerName" 
             class="form-control" required>
      <div ng-show="form.$submitted || form.headerName.$touched">
        <span ng-show="form.headerName.$invalid" 
              class="label-color validation-message">Header Name is required</span>

  <button ng-click="addHeader(form, header)" 
          class="btn btn-default pull-right">Add Header


In your controller you can do;

addHeader(form, header){
        let self = this;
        form.$submitted = true;

You need some css as well;

.label-color {
            color: $gray-color;
.has-error {
       .label-color {
            color: rgb(221, 25, 29);
        .select2-choice.ui-select-match.select2-default {
            border-color: #e84e40;
.validation-message {
       font-size: 0.875em;
    .max-width {
        width: 100%;
        min-width: 100%;

reading and parsing a TSV file, then manipulating it for saving as CSV (*efficiently*)

You should use the csv module to read the tab-separated value file. Do not read it into memory in one go. Each row you read has all the information you need to write rows to the output CSV file, after all. Keep the output file open throughout.

import csv

with open('sample.txt', newline='') as tsvin, open('new.csv', 'w', newline='') as csvout:
    tsvin = csv.reader(tsvin, delimiter='\t')
    csvout = csv.writer(csvout)

    for row in tsvin:
        count = int(row[4])
        if count > 0:
            csvout.writerows([row[2:4] for _ in range(count)])

or, using the itertools module to do the repeating with itertools.repeat():

from itertools import repeat
import csv

with open('sample.txt', newline='') as tsvin, open('new.csv', 'w', newline='') as csvout:
    tsvin = csv.reader(tsvin, delimiter='\t')
    csvout = csv.writer(csvout)

    for row in tsvin:
        count = int(row[4])
        if count > 0:
            csvout.writerows(repeat(row[2:4], count))

How to run a jar file in a linux commandline

copy your file in linux Java directory

cp yourfile.jar /java/bin

open the directory

cd /java/bin

and execute your file

./java -jar yourfile.jar

or all in one try this command:

/java/bin/java -jar jarfilefolder/jarfile.jar

Java, how to compare Strings with String Arrays

Instead of using array you can use the ArrayList directly and can use the contains method to check the value which u have passes with the ArrayList.

How do I make a <div> move up and down when I'm scrolling the page?

Just for a more animated and cute solution:

  $("#div").stop().animate({"marginTop": ($(window).scrollTop()) + "px", "marginLeft":($(window).scrollLeft()) + "px"}, "slow" );

And a pen for those who want to see:, and fork:

Update: and a non-animated jQuery solution:

  $("#div").css({"margin-top": ($(window).scrollTop()) + "px", "margin-left":($(window).scrollLeft()) + "px"});

Bash script processing limited number of commands in parallel

See parallel. Its syntax is similar to xargs, but it runs the commands in parallel.

How to change the time format (12/24 hours) of an <input>?

Even though you see the time in HH:MM AM/PM format, on the backend it still works in 24 hour format, you can try using some basic javascript to see that.

Delete specific line from a text file?

One way to do it if the file is not very big is to load all the lines into an array:

string[] lines = File.ReadAllLines("filename.txt");
string[] newLines = RemoveUnnecessaryLine(lines);
File.WriteAllLines("filename.txt", newLines);

How to copy directories with spaces in the name

When you specify the last Directory on the path remove the last .

for example "\server\directory with space\directory with space".

that should do it.

How can I delete Docker's images?

To delete some Docker image you must execute the following command:

$ docker rmi <docker_image_id>

So, to delete all Docker images you can execute the following command:

$ docker rmi $(docker images -q)

Now, if you want delete all Docker images (including images that are in use), you can add the flag -f, for example:

$ docker rmi -f $(docker images -q)

Parse Error: Adjacent JSX elements must be wrapped in an enclosing tag

You should put your component between an enclosing tag, Which means:


return (  
    <Comp1 />
    <Comp2 />


// Correct

return (
       <Comp1 />
       <Comp2 />

Edit: Per Joe Clay's comment about the Fragments API

// More Correct

return (
       <Comp1 />
       <Comp2 />

// Short syntax

return (
       <Comp1 />
       <Comp2 />

How to join two sets in one line without using "|"

Assuming you also can't use s.union(t), which is equivalent to s | t, you could try

>>> from itertools import chain
>>> set(chain(s,t))
set([1, 2, 3, 4, 5, 6])

Or, if you want a comprehension,

>>> {i for j in (s,t) for i in j}
set([1, 2, 3, 4, 5, 6])

Rerouting stdin and stdout from C

The os function dup2() should provide what you need (if not references to exactly what you need).

More specifically, you can dup2() the stdin file descriptor to another file descriptor, do other stuff with stdin, and then copy it back when you want.

The dup() function duplicates an open file descriptor. Specifically, it provides an alternate interface to the service provided by the fcntl() function using the F_DUPFD constant command value, with 0 for its third argument. The duplicated file descriptor shares any locks with the original.

On success, dup() returns a new file descriptor that has the following in common with the original:

  • Same open file (or pipe)
  • Same file pointer (both file descriptors share one file pointer)
  • Same access mode (read, write, or read/write)

Javascript return number of days,hours,minutes,seconds between two dates

Here's my take:

timeSince(123456) => "1 day, 10 hours, 17 minutes, 36 seconds"

And the code:

function timeSince(date, longText) {
    let seconds = null;
    let leadingText = null;

    if (date instanceof Date) {
        seconds = Math.floor((new Date() - date) / 1000);
        if (seconds < 0) {
            leadingText = " from now";
        } else {
            leadingText = " ago";
        seconds = Math.abs(seconds);
    } else {
        seconds = date;
        leadingText = "";

    const intervals = [
        [31536000, "year"  ],
        [ 2592000, "month" ],
        [   86400, "day"   ],
        [    3600, "hour"  ],
        [      60, "minute"],
        [       1, "second"],

    let interval = seconds;
    let intervalStrings = [];
    for (let i = 0; i < intervals.length; i++) {
        let divResult = Math.floor(interval / intervals[i][0]);
        if (divResult > 0) {
            intervalStrings.push(divResult + " " + intervals[i][1] + ((divResult > 1) ? "s" : ""));
            interval = interval % intervals[i][0];
            if (!longText) {
    let intStr = intervalStrings.join(", ");

    return intStr + leadingText;

Simple Digit Recognition OCR in OpenCV-Python

OCR which stands for Optical Character Recognition is a computer vision technique used to identify the different types of handwritten digits that are used in common mathematics. To perform OCR in OpenCV we will use the KNN algorithm which detects the nearest k neighbors of a particular data point and then classifies that data point based on the class type detected for n neighbors.

Data Used

This data contains 5000 handwritten digits where there are 500 digits for every type of digit. Each digit is of 20×20 pixel dimensions. We will split the data such that 250 digits are for training and 250 digits are for testing for every class.

Below is the implementation.

import numpy as np
import cv2
# Read the image
image = cv2.imread('digits.png')
# gray scale conversion
gray_img = cv2.cvtColor(image,
# We will divide the image
# into 5000 small dimensions 
# of size 20x20
divisions = list(np.hsplit(i,100) for i in np.vsplit(gray_img,50))
# Convert into Numpy array
# of size (50,100,20,20)
NP_array = np.array(divisions)
# Preparing train_data
# and test_data.
# Size will be (2500,20x20)
train_data = NP_array[:,:50].reshape(-1,400).astype(np.float32)
# Size will be (2500,20x20)
test_data = NP_array[:,50:100].reshape(-1,400).astype(np.float32)
# Create 10 different labels 
# for each type of digit
k = np.arange(10)
train_labels = np.repeat(k,250)[:,np.newaxis]
test_labels = np.repeat(k,250)[:,np.newaxis]
# Initiate kNN classifier
knn =
# perform training of data
# obtain the output from the
# classifier by specifying the
# number of neighbors.
ret, output ,neighbours,
distance = knn.findNearest(test_data, k = 3)
# Check the performance and
# accuracy of the classifier.
# Compare the output with test_labels
# to find out how many are wrong.
matched = output==test_labels
correct_OP = np.count_nonzero(matched)
#Calculate the accuracy.
accuracy = (correct_OP*100.0)/(output.size)
# Display accuracy.



Well, I decided to workout myself on my question to solve the above problem. What I wanted is to implement a simple OCR using KNearest or SVM features in OpenCV. And below is what I did and how. (it is just for learning how to use KNearest for simple OCR purposes).

1) My first question was about file that comes with OpenCV samples. I wanted to know what is inside that file.

It contains a letter, along with 16 features of that letter.

And this SOF helped me to find it. These 16 features are explained in the paper Letter Recognition Using Holland-Style Adaptive Classifiers. (Although I didn't understand some of the features at the end)

2) Since I knew, without understanding all those features, it is difficult to do that method. I tried some other papers, but all were a little difficult for a beginner.

So I just decided to take all the pixel values as my features. (I was not worried about accuracy or performance, I just wanted it to work, at least with the least accuracy)

I took the below image for my training data:

enter image description here

(I know the amount of training data is less. But, since all letters are of the same font and size, I decided to try on this).

To prepare the data for training, I made a small code in OpenCV. It does the following things:

  1. It loads the image.
  2. Selects the digits (obviously by contour finding and applying constraints on area and height of letters to avoid false detections).
  3. Draws the bounding rectangle around one letter and wait for key press manually. This time we press the digit key ourselves corresponding to the letter in the box.
  4. Once the corresponding digit key is pressed, it resizes this box to 10x10 and saves all 100 pixel values in an array (here, samples) and corresponding manually entered digit in another array(here, responses).
  5. Then save both the arrays in separate .txt files.

At the end of the manual classification of digits, all the digits in the training data (train.png) are labeled manually by ourselves, image will look like below:

enter image description here

Below is the code I used for the above purpose (of course, not so clean):

import sys

import numpy as np
import cv2

im = cv2.imread('pitrain.png')
im3 = im.copy()

gray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray,(5,5),0)
thresh = cv2.adaptiveThreshold(blur,255,1,1,11,2)

#################      Now finding Contours         ###################

contours,hierarchy = cv2.findContours(thresh,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)

samples =  np.empty((0,100))
responses = []
keys = [i for i in range(48,58)]

for cnt in contours:
    if cv2.contourArea(cnt)>50:
        [x,y,w,h] = cv2.boundingRect(cnt)
        if  h>28:
            roi = thresh[y:y+h,x:x+w]
            roismall = cv2.resize(roi,(10,10))
            key = cv2.waitKey(0)

            if key == 27:  # (escape to quit)
            elif key in keys:
                sample = roismall.reshape((1,100))
                samples = np.append(samples,sample,0)

responses = np.array(responses,np.float32)
responses = responses.reshape((responses.size,1))
print "training complete"


Now we enter in to training and testing part.

For the testing part, I used the below image, which has the same type of letters I used for the training phase.

enter image description here

For training we do as follows:

  1. Load the .txt files we already saved earlier
  2. create an instance of the classifier we are using (it is KNearest in this case)
  3. Then we use KNearest.train function to train the data

For testing purposes, we do as follows:

  1. We load the image used for testing
  2. process the image as earlier and extract each digit using contour methods
  3. Draw a bounding box for it, then resize it to 10x10, and store its pixel values in an array as done earlier.
  4. Then we use KNearest.find_nearest() function to find the nearest item to the one we gave. ( If lucky, it recognizes the correct digit.)

I included last two steps (training and testing) in single code below:

import cv2
import numpy as np

#######   training part    ############### 
samples = np.loadtxt('',np.float32)
responses = np.loadtxt('',np.float32)
responses = responses.reshape((responses.size,1))

model = cv2.KNearest()

############################# testing part  #########################

im = cv2.imread('pi.png')
out = np.zeros(im.shape,np.uint8)
gray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
thresh = cv2.adaptiveThreshold(gray,255,1,1,11,2)

contours,hierarchy = cv2.findContours(thresh,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)

for cnt in contours:
    if cv2.contourArea(cnt)>50:
        [x,y,w,h] = cv2.boundingRect(cnt)
        if  h>28:
            roi = thresh[y:y+h,x:x+w]
            roismall = cv2.resize(roi,(10,10))
            roismall = roismall.reshape((1,100))
            roismall = np.float32(roismall)
            retval, results, neigh_resp, dists = model.find_nearest(roismall, k = 1)
            string = str(int((results[0][0])))


And it worked, below is the result I got:

enter image description here

Here it worked with 100% accuracy. I assume this is because all the digits are of the same kind and the same size.

But anyway, this is a good start to go for beginners (I hope so).

How to delete an SVN project from SVN repository

There's no concept of "project" in svn. So, feel free to delete whatever you think belongs to the project.

What's the best way to set a single pixel in an HTML5 canvas?

function setPixel(imageData, x, y, r, g, b, a) {
    var index = 4 * (x + y * imageData.width);[index+0] = r;[index+1] = g;[index+2] = b;[index+3] = a;

How to display an alert box from C# in ASP.NET?

ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "alertMessage", "alert('Record Inserted Successfully')", true); 

You can use this way, but be sure that there is no Page.Redirect() is used. If you want to redirect to another page then you can try this:


<asp:Button AccessKey="S" ID="submitBtn" runat="server" OnClick="Submit" Text="Submit"
                                        Width="90px" ValidationGroup="vg" CausesValidation="true" OnClientClick = "Confirm()" />

JavaScript code:

function Confirm()
   if (Page_ClientValidate())
      var confirm_value = document.createElement("INPUT");
      confirm_value.type = "hidden"; = "confirm_value";
      if (confirm("Data has been Added. Do you wish to Continue ?"))
         confirm_value.value = "Yes";
         confirm_value.value = "No";

and this is your code behind snippet :

protected void Submit(object sender, EventArgs e)
   string confirmValue = Request.Form["confirm_value"];
   if (confirmValue == "Yes")

This will sure work.

How to Change Margin of TextView

TextView forgot_pswrd = (TextView) findViewById(;
LinearLayout.LayoutParams llp = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
llp.setMargins(50, 0, 0, 0); // llp.setMargins(left, top, right, bottom);

I did this and it worked perfectly. Maybe as you are giving the value in -ve, that's why your code is not working. You just put this code where you are creating the reference of the view.

How to lookup JNDI resources on WebLogic?

I had a similar problem to this one. It got solved by deleting the java:comp/env/ prefix and using jdbc/myDataSource in the context lookup. Just as someone pointed out in the comments.

Foreign key referencing a 2 columns primary key in SQL Server

The Content table likely to have multiple duplicate Application values that can't be mapped to Libraries. Is it possible to drop the Application column from the Libraries Primary Key Index and add it as a Unique Key Index instead?

npm install error - unable to get local issuer certificate

I have encountered the same issue. This command didn't work for me either:

npm config set strict-ssl false

After digging deeper, I found out that this link was block by our IT admin.

So if you are facing the same issue, make sure this link is accessible to your browser first.

Change UITableView height dynamically

Rob's solution is very nice, only thing that in his -(void)adjustHeightOfTableview method the calling of

[self.view needsUpdateConstraints]

does nothing, it just returns a flag, instead calling

[self.view setNeedsUpdateConstraints]

will make the desired effect.

How do I get the time of day in javascript/Node.js?

Check out the moment.js library. It works with browsers as well as with Node.JS. Allows you to write




without prior writing of any functions.

What’s the best way to check if a file exists in C++? (cross platform)

Use stat(), if it is cross-platform enough for your needs. It is not C++ standard though, but POSIX.

On MS Windows there is _stat, _stat64, _stati64, _wstat, _wstat64, _wstati64.

What is the difference between LATERAL and a subquery in PostgreSQL?

Database table

Having the following blog database table storing the blogs hosted by our platform:

Blog table

And, we have two blogs currently hosted:

id created_on title url
1 2013-09-30 Vlad Mihalcea's Blog
2 2017-01-22 Hypersistence

Getting our report without using the SQL LATERAL JOIN

We need to build a report that extracts the following data from the blog table:

  • the blog id
  • the blog age, in years
  • the date for the next blog anniversary
  • the number of days remaining until the next anniversary.

If you're using PostgreSQL, then you have to execute the following SQL query:

SELECT as blog_id,
    YEAR FROM age(now(), b.created_on)
  ) AS age_in_years,
    created_on + (
      extract(YEAR FROM age(now(), b.created_on)) + 1
    ) * interval '1 year'
  ) AS next_anniversary,
    created_on + (
      extract(YEAR FROM age(now(), b.created_on)) + 1
    ) * interval '1 year'
  ) - date(now()) AS days_to_next_anniversary
FROM blog b
ORDER BY blog_id

As you can see, the age_in_years has to be defined three times because you need it when calculating the next_anniversary and days_to_next_anniversary values.

And, that's exactly where LATERAL JOIN can help us.

Getting the report using the SQL LATERAL JOIN

The following relational database systems support the LATERAL JOIN syntax:

  • Oracle since 12c
  • PostgreSQL since 9.3
  • MySQL since 8.0.14

SQL Server can emulate the LATERAL JOIN using CROSS APPLY and OUTER APPLY.

LATERAL JOIN allows us to reuse the age_in_years value and just pass it further when calculating the next_anniversary and days_to_next_anniversary values.

The previous query can be rewritten to use the LATERAL JOIN, as follows:

SELECT as blog_id,
    created_on + (age_in_years + 1) * interval '1 year'
  ) AS next_anniversary,
    created_on + (age_in_years + 1) * interval '1 year'
  ) - date(now()) AS days_to_next_anniversary
FROM blog b
      extract(YEAR FROM age(now(), b.created_on)) AS int
    ) AS age_in_years
) AS t
ORDER BY blog_id

And, the age_in_years value can be calculated one and reused for the next_anniversary and days_to_next_anniversary computations:

blog_id age_in_years next_anniversary days_to_next_anniversary
1 7 2021-09-30 295
2 3 2021-01-22 44

Much better, right?

The age_in_years is calculated for every record of the blog table. So, it works like a correlated subquery, but the subquery records are joined with the primary table and, for this reason, we can reference the columns produced by the subquery.

Can I apply a CSS style to an element name?

You can use the attribute selector,

input[name="goButton"] {_x000D_
  background: red;_x000D_
<input name="goButton">

Be aware that it isn't supported in IE6.

Update: In 2016 you can pretty much use them as you want, since IE6 is dead.

Reading from a text file and storing in a String

These are the necersary imports:


And this is a method that will allow you to read from a File by passing it the filename as a parameter like this: readFile("yourFile.txt");

String readFile(String fileName) throws IOException {
    BufferedReader br = new BufferedReader(new FileReader(fileName));
    try {
        StringBuilder sb = new StringBuilder();
        String line = br.readLine();

        while (line != null) {
            line = br.readLine();
        return sb.toString();
    } finally {

What is the best way to calculate a checksum for a file that is on my machine?

Note that the above solutions will not tell you if your installation is correct only if your install.exe is correct (you can trust it to produce a correct install.)

You would need MD5 sums for each file/folder to test if the installed code has been messed with after the install completed.

WinMerg is useful to compare two installs (on two different machines perhaps) to see if one has been changed or why one is broken.

Resize image proportionally with CSS?

Try this:

div.container {
    max-width: 200px;//real picture size
    max-height: 100px;

/* resize images */
div.container img {
    width: 100%;
    height: auto;

Triggering a checkbox value changed event in DataGridView

Every one of the CellClick and CellMouseClick answers is wrong, because you can change the value of the cell with the keyboard and the event will not fire. Additionally, CurrentCellDirtyStateChanged only fires once, which means if you check/uncheck the same box multiple times, you will only get one event. Combining a few of the answers above gives the following simple solution:

private void dgvList_CurrentCellDirtyStateChanged(object sender, EventArgs e)
    if (dgvList.CurrentCell is DataGridViewCheckBoxCell)

private void dgvList_CellValueChanged(object sender, DataGridViewCellEventArgs e)
    // Now this will fire immediately when a check box cell is changed,
    // regardless of whether the user uses the mouse, keyboard, or touchscreen.
    // Value property is up to date, you DO NOT need EditedFormattedValue here.

Get a filtered list of files in a directory

You can use subprocess.check_ouput() as

import subprocess

list_files = subprocess.check_output("ls 145992*.jpg", shell=True) 

Of course, the string between quotes can be anything you want to execute in the shell, and store the output.

Center content in responsive bootstrap navbar

it because it apply flex. you can use this code

@media (min-width: 992px){
.navbar-expand-lg .navbar-collapse {
    display: -ms-flexbox!important;
    display: flex!important;
    -ms-flex-preferred-size: auto;
    flex-basis: auto;
    justify-content: center;

in my case it workded correctly.

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

WORKING Method { if there is no problem other than configuration }

By Default Appache is not restricting access from ipv4. (common external ip)

What may restrict is the configurations in 'httpd.conf' (or 'apache2.conf' depending on your apache configuration)


Replace all:

<Directory />
     AllowOverride none
    Require all denied



<Directory />
     AllowOverride none
#    Require all denied


hence removing out all restriction given to Apache

Replace Require local with Require all granted at C:/wamp/www/ directory

<Directory "c:/wamp/www/">
    Options Indexes FollowSymLinks
    AllowOverride all
    Require all granted
#   Require local

How do I write a compareTo method which compares objects?

This is the right way to compare strings:

int studentCompare = this.lastName.compareTo(s.getLastName()); 

This won't even compile:

if (this.getLastName() < s.getLastName())

Use if (this.getLastName().compareTo(s.getLastName()) < 0) instead.

So to compare fist/last name order you need:

int d = getFirstName().compareTo(s.getFirstName());
if (d == 0)
    d = getLastName().compareTo(s.getLastName());
return d;

How to get first and last element in an array in java?

This is the given array.

    int myIntegerNumbers[] = {1,2,3,4,5,6,7,8,9,10};

// If you want print the last element in the array.

    int lastNumerOfArray= myIntegerNumbers[9];
    Log.i("MyTag", lastNumerOfArray + "");

// If you want to print the number of element in the array.

    Log.i("MyTag", "The number of elements inside" +
            "the array " +myIntegerNumbers.length);

// Second method to print the last element inside the array.

    Log.i("MyTag", "The last elements inside " +
            "the array " + myIntegerNumbers[myIntegerNumbers.length-1]);

How can I install Visual Studio Code extensions offline?

adding on to t3chb0t's answer, not sure why the option to download is not visible, so created a patch for those who use GreaseMonkey/ TamperMonkey: you can find the gist code here

Or you can just paste the below lines in your browser console, and the link would magically appear:

let version = document.querySelector('.ux-table-metadata > tbody:nth-child(1) > tr:nth-child(1) > td:nth-child(2) > div:nth-child(1)').innerText
    , itemDetails ='?', '').split('&').filter(str => !str.indexOf('itemName')).map(str => str.split('=')[1])[0]
    , [author, extension] = itemDetails.split('.')
    , lAuthor = author.toLowerCase()
    , href = `https://${lAuthor}${author}/extension/${extension}/${version}/assetbyname/Microsoft.VisualStudio.Services.VSIXPackage`
    , element = document.createElement('a');

element.href = href;
element.className = 'vscode-moreinformation dark';
element.innerHTML = 'download .vsix file';  = `${extension}.${version}.vsix`;

Clear text from textarea with selenium

It is general syntax

driver.find_element_by_id('Locator value').clear();
driver.find_element_by_name('Locator value').clear();

What do these operators mean (** , ^ , %, //)?

You are correct that ** is the power function.

^ is bitwise XOR.

% is indeed the modulus operation, but note that for positive numbers, x % m = x whenever m > x. This follows from the definition of modulus. (Additionally, Python specifies x % m to have the sign of m.)

// is a division operation that returns an integer by discarding the remainder. This is the standard form of division using the / in most programming languages. However, Python 3 changed the behavior of / to perform floating-point division even if the arguments are integers. The // operator was introduced in Python 2.6 and Python 3 to provide an integer-division operator that would behave consistently between Python 2 and Python 3. This means:

| context                                | `/` behavior   | `//` behavior |
| floating-point arguments, Python 2 & 3 | float division | int divison   |
| integer arguments, python 2            | int division   | int division  |
| integer arguments, python 3            | float division | int division  |

For more details, see this question: Division in Python 2.7. and 3.3

How to detect orientation change in layout in Android?

If accepted answer doesn't work for you, make sure you didn't define in manifest file:


Which is my case.

How to delete large data of table in SQL without log?

@m-ali answer is right but also keep in mind that logs could grow a lot if you don't commit the transaction after each chunk and perform a checkpoint. This is how I would do it and take this article as reference, with performance tests and graphs:

DECLARE @Deleted_Rows INT;
SET @Deleted_Rows = 1;

WHILE (@Deleted_Rows > 0)


   -- Delete some small number of rows at a time
     DELETE TOP (10000)  LargeTable 
     WHERE readTime < dateadd(MONTH,-7,GETDATE())

     SET @Deleted_Rows = @@ROWCOUNT;

   CHECKPOINT -- for simple recovery model

INSERT INTO...SELECT for all MySQL columns

More Examples & Detail

    INSERT INTO vendors (
     state ,

javax vs java package

java.* packages are the core Java language packages, meaning that programmers using the Java language had to use them in order to make any worthwhile use of the java language.

javax.* packages are optional packages, which provides a standard, scalable way to make custom APIs available to all applications running on the Java platform.

How do I make a C++ macro behave like a function?

C++11 brought us lambdas, which can be incredibly useful in this situation:

#define MACRO(X,Y)                              \
    [&](x_, y_) {                               \
        cout << "1st arg is:" << x_ << endl;    \
        cout << "2nd arg is:" << y_ << endl;    \
        cout << "Sum is:" << (x_ + y_) << endl; \
    }((X), (Y))

You keep the generative power of macros, but have a comfy scope from which you can return whatever you want (including void). Additionally, the issue of evaluating macro parameters multiple times is avoided.

Random numbers with Math.random() in Java

Math.random() generates a number between 0 (inclusive) and 1 (exclusive).

So (int)(Math.random() * max) ranges from 0 to max-1 inclusive.

Then (int)(Math.random() * max) + min ranges from min to max + min - 1, which is not what you want.

Google's formula is correct.

Can't use modulus on doubles?

The % operator is for integers. You're looking for the fmod() function.

#include <cmath>

int main()
    double x = 6.3;
    double y = 2.0;
    double z = std::fmod(x,y);


How to test my servlet using JUnit

Use Selenium for webbased unit tests. There's a Firefox plugin called Selenium IDE which can record actions on the webpage and export to JUnit testcases which uses Selenium RC to run the test server.

VMWare Player vs VMWare Workstation


How does VMware Player compare to VMware Workstation? VMware Player enables you to quickly and easily create and run virtual machines. However, VMware Player lacks many powerful features, remote connections to vSphere, drag and drop upload to vSphere, multiple Snapshots and Clones, and much more.

Not being able to revert snapshots it's a big no for me.

text flowing out of div

You should use overflow:hidden; or scroll

or with php you could short the long words...

How to launch Safari and open URL from iOS app

Because this answer is deprecated since iOS 10.0, a better answer would be:

if #available(iOS 10.0, *) {, options: [:], completionHandler: nil)

y en Objective-c

[[UIApplication sharedApplication] openURL:@"url string" options:@{} completionHandler:^(BOOL success) {
        if (success) {
            NSLog(@"Opened url");

What is the simplest way to write the contents of a StringBuilder to a text file in .NET 1.1?

I know this is an old post and that it wants an answer for .NET 1.1 but there's already a very good answer for that. I thought it would be good to have an answer for those people who land on this post that may have a more recent version of the .Net framework, such as myself when I went looking for an answer to the same question.

In those cases there is an even simpler way to write the contents of a StringBuilder to a text file. It can be done with one line of code. It may not be the most efficient but that wasn't really the question now was it.


UIView background color in Swift

self.view.backgroundColor = UIColor.redColor()

In Swift 3:

self.view.backgroundColor =

Remove or uninstall library previously added : cocoapods

Remove lib from Podfile, then pod install again.

How can I read an input string of unknown length?

Enter while securing an area dynamically


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

char *inputString(FILE* fp, size_t size){
//The size is extended by the input with the value of the provisional
    char *str;
    int ch;
    size_t len = 0;
    str = realloc(NULL, sizeof(*str)*size);//size is start size
    if(!str)return str;
    while(EOF!=(ch=fgetc(fp)) && ch != '\n'){
            str = realloc(str, sizeof(*str)*(size+=16));
            if(!str)return str;

    return realloc(str, sizeof(*str)*len);

int main(void){
    char *m;

    printf("input string : ");
    m = inputString(stdin, 10);
    printf("%s\n", m);

    return 0;

How to pass parameters or arguments into a gradle task

I think you probably want to view the minification of each set of css as a separate task

task minifyBrandACss(type: com.eriwen.gradle.css.tasks.MinifyCssTask) {
     source = "src/main/webapp/css/brandA/styles.css"
     dest = "${buildDir}/brandA/styles.css"

etc etc

BTW executing your minify tasks in an action of the war task seems odd to me - wouldn't it make more sense to make them a dependency of the war task?

Redirect to an external URL from controller action in Spring MVC

You can do it with two ways.


@RequestMapping(value = "/redirect", method = RequestMethod.GET)
public void method(HttpServletResponse httpServletResponse) {
    httpServletResponse.setHeader("Location", projectUrl);


@RequestMapping(value = "/redirect", method = RequestMethod.GET)
public ModelAndView method() {
    return new ModelAndView("redirect:" + projectUrl);

Tab space instead of multiple non-breaking spaces ("nbsp")?

If you're looking to just indent the first sentence in a paragraph, you could do that with a small CSS trick:

p:first-letter {
    margin-left: 5em;

Run a task every x-minutes with Windows Task Scheduler

Some of the links provided are only settings for Windows 2003's version of "Scheduled Tasks"

In Windows Server 2008 the "Tasks" setup only has a box with options for "5 Minutes, 10 minutes, 15 minutes, 30 mins, and 1 hour" (screen shot: where the Window 2003 was a "enter whatever number you want" textbox.

I thought doing an "Export" and editing the XML from: PT30M to PT2M

and importing that as a new task would "trick" Tasks into repeating every 2 mins, but it didn't like that

My workaround for getting a task to run every 2 mins in Windows 2008 was to (ugggh) setup 30 different "triggers" for my task repeating every hour but staring at :00, :02, :04, :06 and so on and so on.... took me 8-10 mins to setup but I only had to do it once :-)

Use getElementById on HTMLElement instead of HTMLDocument

I would use XMLHTTP request to retrieve page content as much faster. Then it is easy enough to use querySelectorAll to apply a CSS class selector to grab by class name. Then you access the child elements by tag name and index.

Option Explicit
Public Sub GetInfo()
    Dim sResponse As String, html As HTMLDocument, elements As Object, i As Long

    With CreateObject("MSXML2.XMLHTTP")
        .Open "GET", "", False
        .setRequestHeader "If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT"
        sResponse = StrConv(.responseBody, vbUnicode)
    End With
    Set html = New HTMLDocument
    With html
        .body.innerHTML = sResponse
        Set elements = .querySelectorAll(".profile-col1")
        For i = 0 To elements.Length - 1
            Debug.Print String(20, Chr$(61))
            Debug.Print elements.item(i).getElementsByTagName("a")(0).innerText
            Debug.Print elements.item(i).getElementsByTagName("p")(0).innerText
            Debug.Print elements.item(i).getElementsByTagName("p")(1).innerText
    End With
End Sub


VBE > Tools > References > Microsoft HTML Object Library

How to save data in an android app

There is a lot of options to store your data and Android offers you to chose anyone Your data storage options are the following:

Shared Preferences Store private primitive data in key-value pairs. Internal Storage Store private data on the device memory. External Storage Store public data on the shared external storage. SQLite Databases Store structured data in a private database. Network Connection Store data on the web with your own network server

Check here for examples and tuto

Correct redirect URI for Google API and OAuth 2.0

There's no problem with using a localhost url for Dev work - obviously it needs to be changed when it comes to production.

You need to go here: and then follow the link for the API Console - link's in the Basic Steps section. When you've filled out the new application form you'll be asked to provide a redirect Url. Put in the page you want to go to once access has been granted.

When forming the Google oAuth Url - you need to include the redirect url - it has to be an exact match or you'll have problems. It also needs to be UrlEncoded.

Can't find bundle for base name /Bundle, locale en_US

I had the same problemo, and balus solution fixed it.

For the record:

WEB-INF\faces-config is

<?xml version="1.0" encoding="UTF-8"?>

And had under WebContent\Resources (after mkyong's tutorial)

the pesky exception appeared even when i renamed the bundle to "Message_en_us" and "Message_en". Moving it to src\ worked.

Should someone post the missing piece to make bundles work under resources,it would be a beautiful thing.

Why use Optional.of over Optional.ofNullable?

Your question is based on assumption that the code which may throw NullPointerException is worse than the code which may not. This assumption is wrong. If you expect that your foobar is never null due to the program logic, it's much better to use Optional.of(foobar) as you will see a NullPointerException which will indicate that your program has a bug. If you use Optional.ofNullable(foobar) and the foobar happens to be null due to the bug, then your program will silently continue working incorrectly, which may be a bigger disaster. This way an error may occur much later and it would be much harder to understand at which point it went wrong.

Same font except its weight seems different on different browsers

There's some great information about this here:

Still experimenting but so far a minimally invasive solution, aimed only at FF is:

body {
-moz-osx-font-smoothing: grayscale;

How to get list of dates between two dates in mysql select query


select * from 
(select adddate('1970-01-01',t4.i*10000 + t3.i*1000 + t2.i*100 + t1.i*10 + t0.i) selected_date from
 (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t0,
 (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t1,
 (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t2,
 (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t3,
 (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t4) v
where selected_date between '2012-02-10' and '2012-02-15'

-for date ranges up to nearly 300 years in the future.

[Corrected following a suggested edit by UrvishAtSynapse.]

Android file chooser

EDIT (02 Jan 2012):

I created a small open source Android Library Project that streamlines this process, while also providing a built-in file explorer (in case the user does not have one present). It's extremely simple to use, requiring only a few lines of code.

You can find it at GitHub: aFileChooser.


If you want the user to be able to choose any file in the system, you will need to include your own file manager, or advise the user to download one. I believe the best you can do is look for "openable" content in an Intent.createChooser() like this:

private static final int FILE_SELECT_CODE = 0;

private void showFileChooser() {
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT); 

    try {
                Intent.createChooser(intent, "Select a File to Upload"),
    } catch (android.content.ActivityNotFoundException ex) {
        // Potentially direct the user to the Market with a Dialog
        Toast.makeText(this, "Please install a File Manager.", 

You would then listen for the selected file's Uri in onActivityResult() like so:

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
        case FILE_SELECT_CODE:
        if (resultCode == RESULT_OK) {
            // Get the Uri of the selected file 
            Uri uri = data.getData();
            Log.d(TAG, "File Uri: " + uri.toString());
            // Get the path
            String path = FileUtils.getPath(this, uri);
            Log.d(TAG, "File Path: " + path);
            // Get the file instance
            // File file = new File(path);
            // Initiate the upload
    super.onActivityResult(requestCode, resultCode, data);

The getPath() method in my is:

public static String getPath(Context context, Uri uri) throws URISyntaxException {
    if ("content".equalsIgnoreCase(uri.getScheme())) {
        String[] projection = { "_data" };
        Cursor cursor = null;

        try {
            cursor = context.getContentResolver().query(uri, projection, null, null, null);
            int column_index = cursor.getColumnIndexOrThrow("_data");
            if (cursor.moveToFirst()) {
                return cursor.getString(column_index);
        } catch (Exception e) {
            // Eat it
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();

    return null;

How can I check MySQL engine type for a specific table?


will format it much nicer compared to the output of

SHOW CREATE TABLE <tablename>;

The \G trick is also useful to remember for many other queries/commands.

Eclipse error: indirectly referenced from required .class files?

It happens to me sometimes, I always fixed that with "mvn eclipse:clean" command to clean old properties and then run mvn eclipse:eclipse -Dwtpversion=2.0 (for web project of course). There are some old properties saved so eclipse is confused sometimes.

Programmatically go back to the previous fragment in the backstack

To elaborate on the other answers provided, this is my solution (placed in an Activity):

public void onBackPressed(){
    FragmentManager fm = getFragmentManager();
    if (fm.getBackStackEntryCount() > 0) {
        Log.i("MainActivity", "popping backstack");
    } else {
        Log.i("MainActivity", "nothing on backstack, calling super");

Java output formatting for Strings

For decimal values you can use DecimalFormat

import java.text.*;

public class DecimalFormatDemo {

   static public void customFormat(String pattern, double value ) {
      DecimalFormat myFormatter = new DecimalFormat(pattern);
      String output = myFormatter.format(value);
      System.out.println(value + "  " + pattern + "  " + output);

   static public void main(String[] args) {

      customFormat("###,###.###", 123456.789);
      customFormat("###.##", 123456.789);
      customFormat("000000.000", 123.78);
      customFormat("$###,###.###", 12345.67);  

and output will be:

123456.789  ###,###.###   123,456.789
123456.789  ###.##        123456.79
123.78      000000.000    000123.780
12345.67    $###,###.###  $12,345.67

For more details look here:

How do I read input character-by-character in Java?

Use A return value of -1 means end of stream; else, cast to char.

This code reads character data from a list of file arguments:

public class CharacterHandler {
    //Java 7 source level
    public static void main(String[] args) throws IOException {
        // replace this with a known encoding if possible
        Charset encoding = Charset.defaultCharset();
        for (String filename : args) {
            File file = new File(filename);
            handleFile(file, encoding);

    private static void handleFile(File file, Charset encoding)
            throws IOException {
        try (InputStream in = new FileInputStream(file);
             Reader reader = new InputStreamReader(in, encoding);
             // buffer for efficiency
             Reader buffer = new BufferedReader(reader)) {

    private static void handleCharacters(Reader reader)
            throws IOException {
        int r;
        while ((r = != -1) {
            char ch = (char) r;
            System.out.println("Do something with " + ch);

The bad thing about the above code is that it uses the system's default character set. Wherever possible, prefer a known encoding (ideally, a Unicode encoding if you have a choice). See the Charset class for more. (If you feel masochistic, you can read this guide to character encoding.)

(One thing you might want to look out for are supplementary Unicode characters - those that require two char values to store. See the Character class for more details; this is an edge case that probably won't apply to homework.)

Split string by single spaces

You could used simple strtok() function (*)From here. Note that tokens are created on delimiters

#include <stdio.h>
#include <string.h>

int main ()
  char str[] ="- This is a string";
  char * pch;
  printf ("Splitting string \"%s\" into tokens:\n",str);
  pch = strtok (str," ,.-");
  while (pch != NULL)
    printf ("%s\n",pch);
    pch = strtok (NULL, " ,.-");
  return 0;

if checkbox is checked, do this

I would use .change() and this.checked:

    var c = this.checked ? '#f00' : '#09f';
    $('p').css('color', c);


On using this.checked
Andy E has done a great write-up on how we tend to overuse jQuery: Utilizing the awesome power of jQuery to access properties of an element. The article specifically treats the use of .attr("id") but in the case that #checkbox is an <input type="checkbox" /> element the issue is the same for $(...).attr('checked') (or even $(...).is(':checked')) vs. this.checked.

how to generate public key from windows command prompt

If you've got git-bash installed (which comes with Git, Github for Windows, or Visual Studio 2015), then that includes a Windows version of ssh-keygen.

How to change Tkinter Button state from disabled to normal?

I think a quick way to change the options of a widget is using the configure method.

In your case, it would look like this:


Reading settings from app.config or web.config in .NET

You can use the below line. In my case it was working: System.Configuration.ConfigurationSettings.AppSettings["yourKeyName"]

You must take care that the above line of code is also the old version and it's deprecated in new libraries.

Correctly determine if date string is a valid date in that format

Returns TRUE if the input parameter is a valid date string in "YYYY-MM-DD" format (aka "MySQL date format")
The date separator can be only the '-' character.
function isMysqlDate($yyyymmdd)
    return checkdate(substr($yyyymmdd, 5, 2), substr($yyyymmdd, 8), substr($yyyymmdd, 0, 4)) 
        && (substr($yyyymmdd, 4, 1) === '-') 
        && (substr($yyyymmdd, 7, 1) === '-');

Set value for particular cell in pandas DataFrame using index

Soo, your question to convert NaN at ['x',C] to value 10

the answer is..


alternative code is

df.loc['C', 'x']=10

Split pandas dataframe in two if it has more than 10 rows

I used a List Comprehension to cut a huge DataFrame into blocks of 100'000:

size = 100000
list_of_dfs = [df.loc[i:i+size-1,:] for i in range(0, len(df),size)]

or as generator:

list_of_dfs = (df.loc[i:i+size-1,:] for i in range(0, len(df),size))

How to access custom attributes from event object in React?

I do not know about React, but in the general case you can pass custom attributes like this:

1) define inside an html-tag a new attribute with data- prefix

data-mydatafield = "asdasdasdaad"

2) get from javascript with"data-mydatafield").value 

How to change time in DateTime?

one liner

var date = DateTime.Now.Date.Add(new TimeSpan(4, 30, 0));

would bring back todays date with a time of 4:30:00, replace DateTime.Now with any date object

What is "entropy and information gain"?

I really recommend you read about Information Theory, bayesian methods and MaxEnt. The place to start is this (freely available online) book by David Mackay:

Those inference methods are really far more general than just text mining and I can't really devise how one would learn how to apply this to NLP without learning some of the general basics contained in this book or other introductory books on Machine Learning and MaxEnt bayesian methods.

The connection between entropy and probability theory to information processing and storing is really, really deep. To give a taste of it, there's a theorem due to Shannon that states that the maximum amount of information you can pass without error through a noisy communication channel is equal to the entropy of the noise process. There's also a theorem that connects how much you can compress a piece of data to occupy the minimum possible memory in your computer to the entropy of the process that generated the data.

I don't think it's really necessary that you go learning about all those theorems on communication theory, but it's not possible to learn this without learning the basics about what is entropy, how it's calculated, what is it's relationship with information and inference, etc...

How to advance to the next form input when the current input has a value?

This should work. Working with and without tabindex.

var currentlyFocused = undefined;_x000D_
var tabableElements = undefined;_x000D_
 * Compare function for element sort_x000D_
 * @param {string | null} a_x000D_
 * @param {string | null} b_x000D_
 * @param {boolean} asc_x000D_
function sortCompare(a, b, asc = true) {_x000D_
  let result = null;_x000D_
  if (a == null) result = 1;_x000D_
  else if (b == null) result = -1;_x000D_
  else if (parseInt(a) > parseInt(b)) result = 1;_x000D_
  else if (parseInt(a) < parseInt(b)) result = -1;_x000D_
  else result = 0;_x000D_
  return result * (asc ? 1 : -1);_x000D_
 * When an element is focused assign it to the currentlyFocused variable_x000D_
 * @param {Element} element_x000D_
function registerOnElementFocus(element) {_x000D_
  element.addEventListener("focus", function(el) {_x000D_
    currentlyFocused = el.srcElement;_x000D_
 * Tab Trigger_x000D_
function onTabClick() {_x000D_
  //Select currently focused element_x000D_
  let currentIndex;_x000D_
  tabableElements.forEach((el, idx) => {_x000D_
    //return if no element is focused_x000D_
    if (!currentlyFocused) return;_x000D_
    if (currentlyFocused.isEqualNode(el)) {_x000D_
      //assign current index and return_x000D_
      currentIndex = idx;_x000D_
  //if theres no focused element or the current focused element is last start over_x000D_
  let lastIndex = tabableElements.length - 1;_x000D_
  let nextElementidx = currentIndex === undefined || currentIndex == lastIndex ? 0 : currentIndex + 1;_x000D_
  currentlyFocused = tabableElements[nextElementidx];_x000D_
 * Init must be run after all elements are loadead in the dom_x000D_
function init() {_x000D_
  //Get all tab-able elements_x000D_
  let nodeList = document.querySelectorAll("input, button, a, area, object, select, textarea, [tabindex]");_x000D_
  //To array for easier manipulation_x000D_
  tabableElements =, 0);_x000D_
  //Correcting tabindexes to ensure correct order_x000D_
  tabableElements.forEach((el, idx, list) => {_x000D_
    let tabindex = el.getAttribute("tabindex");_x000D_
    //-1 tabindex will not receive focus_x000D_
    if (tabindex == -1) list.splice(idx, 1);_x000D_
    //null or 0 tabindex in normal source order_x000D_
    else if (tabindex == null || tabindex == 0) {_x000D_
      list[idx].setAttribute("tabindex", 9999 + idx);_x000D_
  //sort elements by their tabindex in ascending order_x000D_
  tabableElements.sort((elementA, elementB) => sortCompare(elementA.getAttribute("tabindex"), elementB.getAttribute("tabindex")));_x000D_
  //register focus event to elements_x000D_
  tabableElements.forEach(el => registerOnElementFocus(el));_x000D_
<!doctype html>_x000D_
<html lang="en">_x000D_
  <!-- Required meta tags -->_x000D_
  <meta charset="utf-8">_x000D_
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">_x000D_
  <!-- Bootstrap CSS -->_x000D_
  <link rel="stylesheet" href="" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">_x000D_
  <title>Virtual tab</title>_x000D_
<body onload="init()">_x000D_
  <div class="container">_x000D_
    <h3>Virtual Tab Demo</h3>_x000D_
      <div class="btn btn-primary" style="position: fixed;" onclick="onTabClick()">_x000D_
      <button id="button1" type="button" onclick="alert('button 1')">Button1</button>_x000D_
      <button id="button2" type="button" onclick="alert('button 2')">Button2</button>_x000D_
      <input id="text" type='text'>text_x000D_
      <input id="password" type='password' tabindex="-1">password_x000D_
      <input id="number" type='number' tabindex="5">number_x000D_
      <input id="checkbox" type='checkbox'>checkbox_x000D_
      <input id="radio" type='radio'>radio_x000D_
      <button id="button3" type="button" onclick="alert('button 3')">Button3</button>_x000D_
      <button id="button4" type="button" onclick="alert('button 4')">Button4</button>_x000D_
      <select id="select">_x000D_
        <option value="volvo">Volvo</option>_x000D_
        <option value="saab">Saab</option>_x000D_
        <option value="mercedes">Mercedes</option>_x000D_
        <option value="audi">Audi</option>_x000D_
      <br> textarea_x000D_
      <textarea id="textarea"></textarea>_x000D_
        <span id="span" tabindex="1">Focus other elements.</span>_x000D_
  <!-- Optional JavaScript -->_x000D_
  <!-- jQuery first, then Popper.js, then Bootstrap JS -->_x000D_
  <script src="" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>_x000D_
  <script src="" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>_x000D_
  <script src="" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>_x000D_

AttributeError: 'list' object has no attribute 'encode'

You need to do encode on tmp[0], not on tmp.

tmp is not a string. It contains a (Unicode) string.

Try running type(tmp) and print dir(tmp) to see it for yourself.

Using "word-wrap: break-word" within a table

table-layout: fixed will get force the cells to fit the table (and not the other way around), e.g.:

<table style="border: 1px solid black; width: 100%; word-wrap:break-word;
              table-layout: fixed;">


the origin server can create the resource with that URI

So you use POST and probably, but not necessary PUT for resource creation. You don't have to support both. For me POST is perfectly enough. So it is a design decision.

As your quote mentioned, you use PUT for creation of there is no resource assigned to an IRI, and you want to create a resource anyway. For example, PUT /users/123/password usually replaces the old password with a new one, but you can use it to create a password if it does not exist already (for example, by freshly registered users or by restoring banned users).

Why use sys.path.append(path) instead of sys.path.insert(1, path)?

If you really need to use sys.path.insert, consider leaving sys.path[0] as it is:

sys.path.insert(1, path_to_dev_pyworkbooks)

This could be important since 3rd party code may rely on sys.path documentation conformance:

As initialized upon program startup, the first item of this list, path[0], is the directory containing the script that was used to invoke the Python interpreter.

Parsing JSON from URL

You could use for downloading and org.json.JSONTokener for parsing:

JSONObject jo = (JSONObject) new JSONTokener(IOUtils.toString(new URL(""))).nextValue();

nodejs - How to read and output jpg image?

Here is how you can read the entire file contents, and if done successfully, start a webserver which displays the JPG image in response to every request:

var http = require('http')
var fs = require('fs')

fs.readFile('image.jpg', function(err, data) {
  if (err) throw err // Fail if the file can't be read.
  http.createServer(function(req, res) {
    res.writeHead(200, {'Content-Type': 'image/jpeg'})
    res.end(data) // Send the file data to the browser.
  console.log('Server running at http://localhost:8124/')

Note that the server is launched by the "readFile" callback function and the response header has Content-Type: image/jpeg.

[Edit] You could even embed the image in an HTML page directly by using an <img> with a data URI source. For example:

  res.writeHead(200, {'Content-Type': 'text/html'});
  res.write('<html><body><img src="data:image/jpeg;base64,')

How to have stored properties in Swift, the same way I had on Objective-C?

So I think I found a method that works cleaner than the ones above because it doesn't require any global variables. I got it from here:

The gist is that you use a struct like so:

extension UIViewController {
    private struct AssociatedKeys {
        static var DescriptiveName = "nsh_DescriptiveName"

    var descriptiveName: String? {
        get {
            return objc_getAssociatedObject(self, &AssociatedKeys.DescriptiveName) as? String
        set {
            if let newValue = newValue {
                    newValue as NSString?,

UPDATE for Swift 2

private struct AssociatedKeys {
    static var displayed = "displayed"

//this lets us check to see if the item is supposed to be displayed or not
var displayed : Bool {
    get {
        guard let number = objc_getAssociatedObject(self, &AssociatedKeys.displayed) as? NSNumber else {
            return true
        return number.boolValue

    set(value) {
        objc_setAssociatedObject(self,&AssociatedKeys.displayed,NSNumber(bool: value),objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)

Using Node.JS, how do I read a JSON file into (server) memory?

In Node 8 you can use the built-in util.promisify() to asynchronously read a file like this

const {promisify} = require('util')
const fs = require('fs')
const readFileAsync = promisify(fs.readFile)

readFileAsync(`${__dirname}/my.json`, {encoding: 'utf8'})
  .then(contents => {
    const obj = JSON.parse(contents)
  .catch(error => {
    throw error