Programs & Examples On #Jts

The JTS Topology Suite is an open source API of 2D spatial predicates and functions written in Java.

Writing data to a local text file with javascript


<div id="addnew">
    <input type="text" id="id">
    <input type="text" id="content">
    <input type="button" value="Add" id="submit">

<div id="check">
    <input type="text" id="input">
    <input type="button" value="Search" id="search">

JS (writing to the txt file):

function writeToFile(d1, d2){
    var fso = new ActiveXObject("Scripting.FileSystemObject");
    var fh = fso.OpenTextFile("data.txt", 8, false, 0);
    fh.WriteLine(d1 + ',' + d2);
var submit = document.getElementById("submit");
submit.onclick = function () {
    var id      = document.getElementById("id").value;
    var content = document.getElementById("content").value;
    writeToFile(id, content);

checking a particular row:

function readFile(){
    var fso = new ActiveXObject("Scripting.FileSystemObject");
    var fh = fso.OpenTextFile("data.txt", 1, false, 0);
    var lines = "";
    while (!fh.AtEndOfStream) {
        lines += fh.ReadLine() + "\r";
    return lines;
var search = document.getElementById("search");
search.onclick = function () {
    var input   = document.getElementById("input").value;
    if (input != "") {
        var text    = readFile();
        var lines   = text.split("\r");
        var result;
        for (var i = 0; i < lines.length; i++) {
            if (lines[i].match(new RegExp(input))) {
                result = "Found: " + lines[i].split(",")[1];
        if (result) { alert(result); }
        else { alert(input + " not found!"); }

Put these inside a .hta file and run it. Tested on W7, IE11. It's working. Also if you want me to explain what's going on, say so.

Convert an integer to an array of digits

Try this!

int num = 1234; 

String s = Integer.toString(num); 

int[] intArray = new int[s.length()]; 

for(int i=0; i<s.length(); i++){
    intArray[i] = Character.getNumericValue(s.charAt(i));

PHP php_network_getaddresses: getaddrinfo failed: No such host is known

Your target domain might refuse to send you information. This can work as a filter based on browser agent or any other header information. This is a defense against bots, crawlers or any unwanted applications.

Iterate through <select> options

After try several code, and still not working, I go to official documentation of select2.js. here the link:

from that the way to clear selection select2 js is:


Git push won't do anything (everything up-to-date)

I tried many methods including defined here. What I got is,

  • Make sure the name of repository is valid. The best way is to copy the link from repository site and paste in git bash.

  • Make sure you have commited the selected files.

    git commit -m "Your commit here"
  • If both steps don't work, try

    git push -u -f origin master

Preprocessor check if multiple defines are not defined

FWIW, @SergeyL's answer is great, but here is a slight variant for testing. Note the change in logical or to logical and.

main.c has a main wrapper like this:

#if !defined(TEST_SPI) && !defined(TEST_SERIAL) && !defined(TEST_USB)
int main(int argc, char *argv[]) {
  // the true main() routine.

spi.c, serial.c and usb.c have main wrappers for their respective test code like this:

#ifdef TEST_USB
int main(int argc, char *argv[]) {
  // the  main() routine for testing the usb code.

config.h Which is included by all the c files has an entry like this:

// Uncomment below to test the serial
//#define TEST_SERIAL

// Uncomment below to test the spi code
//#define TEST_SPI

// Uncomment below to test the usb code
#define TEST_USB

Display JSON as HTML

SyntaxHighlighter is a fully functional self-contained code syntax highlighter developed in JavaScript. To get an idea of what SyntaxHighlighter is capable of, have a look at the demo page.

python: urllib2 how to send cookie with urlopen request

Use cookielib. The linked doc page provides examples at the end. You'll also find a tutorial here.

Getter and Setter?

Well, PHP does have magic methods __get, __set, __isset & __unset, which is always a start. Alas proper (get it?) OO properties is more than magic methods. The main problem with PHP's implementation is that magic methods are called for all inaccessible properties. Which means you have to Repeat Yourself (eg. by calling property_exists()) in the magic methods when determining if name is actually a property of your object. And you can't really solve this general problem with a base class unless all your classes inherit from ie. ClassWithProperties, since PHP lacks multiple inheritance.

In contrast, Python new style classes gives you property(), which lets you explicitly define all your properties. C# has special syntax.

What's the proper way to "go get" a private repository?

If you've already got git using SSH, this answer by Ammar Bandukwala is a simple workaround:

$ go get uses git internally. The following one liners will make git and consequently $ go get clone your package via SSH.


$ git config --global url."[email protected]:".insteadOf ""


$ git config --global url."[email protected]:".insteadOf ""

Disable output buffering

(I've posted a comment, but it got lost somehow. So, again:)

  1. As I noticed, CPython (at least on Linux) behaves differently depending on where the output goes. If it goes to a tty, then the output is flushed after each '\n'
    If it goes to a pipe/process, then it is buffered and you can use the flush() based solutions or the -u option recommended above.

  2. Slightly related to output buffering:
    If you iterate over the lines in the input with

    for line in sys.stdin:

then the for implementation in CPython will collect the input for a while and then execute the loop body for a bunch of input lines. If your script is about to write output for each input line, this might look like output buffering but it's actually batching, and therefore, none of the flush(), etc. techniques will help that. Interestingly, you don't have this behaviour in pypy. To avoid this, you can use

while True: line=sys.stdin.readline()

How to clear all inputs, selects and also hidden fields in a form using jQuery?

I had a slightly more specialised case, a search form which had an input which had autocomplete for a person name. The Javascript code set a hidden input which from.reset() does not clear.

However I didn't want to reset all hidden inputs. There I added a class, search-value, to the hidden inputs which where to be cleared.

$('form#search-form input[type=hidden].search-value').val('');

How do I deploy Node.js applications as a single executable file?

In addition to nexe, browserify can be used to bundle up all your dependencies as a single .js file. This does not bundle the actual node executable, just handles the javascript side. It too does not handle native modules. The command line options for pure node compilation would be browserify --output bundle.js --bare --dg false input.js.

Passing arguments to an interactive program non-interactively

Many ways

pipe your input

echo "yes
maybe" | your_program

redirect from a file

your_program < answers.txt

use a here document (this can be very readable)

your_program << ANSWERS

use a here string

your_program <<< $'yes\nno\nmaybe\n'

Change image onmouseover

Thy to put a dot or two before the /


How SQL query result insert in temp table?

Look at SELECT INTO. This will create a new table for you, which can be temporary if you want by prefixing the table name with a pound sign (#).

For example, you can do:

INTO #YourTempTable
FROM YourReportQuery

How to remove items from a list while iterating?

Most of the answers here want you to create a copy of the list. I had a use case where the list was quite long (110K items) and it was smarter to keep reducing the list instead.

First of all you'll need to replace foreach loop with while loop,

i = 0
while i < len(somelist):
    if determine(somelist[i]):
         del somelist[i]
        i += 1

The value of i is not changed in the if block because you'll want to get value of the new item FROM THE SAME INDEX, once the old item is deleted.

Unsupported major.minor version 52.0

I could solve the same problem using the below solution.

In my project, I added a JAR file which were created in Java 8. And my project was referring to JRE 7. When I changed project JRE to 8, my problem was solved.


In Eclipse, right click on the project name in project explorer ? Build path ? Libraries ? click on JRE version ? click Edit ? Installed JRE ? Add ? Standerd VM ? select JRE home click-path (path should be localePath\java\jdk1.8.0_25\jre) ? provide name ? Save ? select same JRE for project ? Finish ? OK. Refresh/build project once ? try to run your Java file. It should work.

Difference between string and char[] types in C++

Strings have helper functions and manage char arrays automatically. You can concatenate strings, for a char array you would need to copy it to a new array, strings can change their length at runtime. A char array is harder to manage than a string and certain functions may only accept a string as input, requiring you to convert the array to a string. It's better to use strings, they were made so that you don't have to use arrays. If arrays were objectively better we wouldn't have strings.

Switching between GCC and Clang/LLVM using CMake

CMake honors the environment variables CC and CXX upon detecting the C and C++ compiler to use:

$ export CC=/usr/bin/clang
$ export CXX=/usr/bin/clang++
$ cmake ..
-- The C compiler identification is Clang
-- The CXX compiler identification is Clang

The compiler specific flags can be overridden by putting them into a make override file and pointing the CMAKE_USER_MAKE_RULES_OVERRIDE variable to it. Create a file ~/ClangOverrides.txt with the following contents:

SET (CMAKE_C_FLAGS_INIT                "-Wall -std=c99")

SET (CMAKE_CXX_FLAGS_INIT                "-Wall")

The suffix _INIT will make CMake initialize the corresponding *_FLAGS variable with the given value. Then invoke cmake in the following way:

$ cmake -DCMAKE_USER_MAKE_RULES_OVERRIDE=~/ClangOverrides.txt ..

Finally to force the use of the LLVM binutils, set the internal variable _CMAKE_TOOLCHAIN_PREFIX. This variable is honored by the CMakeFindBinUtils module:

$ cmake -D_CMAKE_TOOLCHAIN_PREFIX=llvm- ..

Putting this all together you can write a shell wrapper which sets up the environment variables CC and CXX and then invokes cmake with the mentioned variable overrides.

Also see this CMake FAQ on make override files.

Makefiles with source files in different directories

You can add rules to your root Makefile in order to compile the necessary cpp files in other directories. The Makefile example below should be a good start in getting you to where you want to be.


SOURCE = cppTest.cpp
SOURCE = $(OTHERDIR)/file.cpp

## End sources definition
## end more includes

OBJ=$(join $(addsuffix ../obj/, $(dir $(SOURCE))), $(notdir $(SOURCE:.cpp=.o))) 

## Fix dependency destination to be ../.dep relative to the src dir
DEPENDS=$(join $(addsuffix ../.dep/, $(dir $(SOURCE))), $(notdir $(SOURCE:.cpp=.d)))

## Default rule executed
all: $(TARGET)

## Clean Rule
        @-rm -f $(TARGET) $(OBJ) $(DEPENDS)

## Rule for making the actual target
        @echo "============="
        @echo "Linking the target $@"
        @echo "============="
        @$(CC) $(CFLAGS) -o $@ $^ $(LIBS)
        @echo -- Link finished --

## Generic compilation rule
%.o : %.cpp
        @mkdir -p $(dir $@)
        @echo "============="
        @echo "Compiling $<"
        @$(CC) $(CFLAGS) -c $< -o $@

## Rules for object files from cpp files
## Object file for each file is put in obj directory
## one level up from the actual source directory.
../obj/%.o : %.cpp
        @mkdir -p $(dir $@)
        @echo "============="
        @echo "Compiling $<"
        @$(CC) $(CFLAGS) -c $< -o $@

# Rule for "other directory"  You will need one per "other" dir
$(OTHERDIR)/../obj/%.o : %.cpp
        @mkdir -p $(dir $@)
        @echo "============="
        @echo "Compiling $<"
        @$(CC) $(CFLAGS) -c $< -o $@

## Make dependancy rules
../.dep/%.d: %.cpp
        @mkdir -p $(dir $@)
        @echo "============="
        @echo Building dependencies file for $*.o
        @$(SHELL) -ec '$(CC) -M $(CFLAGS) $< | sed "s^$*.o^../obj/$*.o^" > $@'

## Dependency rule for "other" directory
$(OTHERDIR)/../.dep/%.d: %.cpp
        @mkdir -p $(dir $@)
        @echo "============="
        @echo Building dependencies file for $*.o
        @$(SHELL) -ec '$(CC) -M $(CFLAGS) $< | sed "s^$*.o^$(OTHERDIR)/../obj/$*.o^" > $@'

## Include the dependency files
-include $(DEPENDS)

npm ERR! Error: EPERM: operation not permitted, rename

I was getting the same thing. I didn't find this anywhere but it hit me that our VMs tend to change files to a read-only state. So I opened package.json's file properties and deselected Read-only in the "General" tab.


  1. Go to the package.json file.
  2. Right-click and select Properties.
  3. In the General tab, Attributes section, deselect Read-only.
  4. Click Apply to apply the change.

How to use terminal commands with Github?

You can't push into other people's repositories. This is because push permanently gets code into their repository, which is not cool.

What you should do, is to ask them to pull from your repository. This is done in GitHub by going to the other repository and sending a "pull request".

There is a very informative article on the GitHub's help itself:

To interact with your own repository, you have the following commands. I suggest you start reading on Git a bit more for these instructions (lots of materials online).

To add new files to the repository or add changed files to staged area:

$ git add <files>

To commit them:

$ git commit

To commit unstaged but changed files:

$ git commit -a

To push to a repository (say origin):

$ git push origin

To push only one of your branches (say master):

$ git push origin master

To fetch the contents of another repository (say origin):

$ git fetch origin

To fetch only one of the branches (say master):

$ git fetch origin master

To merge a branch with the current branch (say other_branch):

$ git merge other_branch

Note that origin/master is the name of the branch you fetched in the previous step from origin. Therefore, updating your master branch from origin is done by:

$ git fetch origin master
$ git merge origin/master

You can read about all of these commands in their manual pages (either on your linux or online), or follow the GitHub helps:

Create hive table using "as select" or "like" and also specify delimiter

Let's say we have an external table called employee

hive> SHOW CREATE TABLE employee;
  id string,
  fname string,
  lname string, 
  salary double)
  1. To create a person table like employee

    CREATE TABLE person LIKE employee;

  2. To create a person external table like employee

    CREATE TABLE person LIKE employee LOCATION 'maprfs:/user/hadoop/data/person';

  3. then use DESC person; to see the newly created table schema.

Best way to check for null values in Java?

In Java 7, you can use Objects.requireNonNull(). Add an import of Objects class from java.util.

public class FooClass {
    public void acceptFoo(Foo obj) {
        //If obj is null, NPE is thrown
        Objects.requireNonNull(obj).bar(); //or better requireNonNull(obj, "obj is null");

What does the "static" modifier after "import" mean?

Very good exaple. npt tipical with MAth in wwww....

public class MyStaticMembClass {
    public static final int INCREMENT = 2;
    public static int incrementNumber(int number){
        return number+INCREMENT;

in onother file inlude

import static com.java2novice.stat.imp.pac1.MyStaticMembClass.*;

What does "TypeError 'xxx' object is not callable" means?

I came across this error message through a silly mistake. A classic example of Python giving you plenty of room to make a fool of yourself. Observe:

class DOH(object):
def __init__(self, property=None):

def property():
    return property

x = DOH(1)


$ python3
Traceback (most recent call last):
  File "", line 9, in <module>
TypeError: 'int' object is not callable

The problem here of course is that the function is overwritten with a property.

Using HttpClient and HttpPost in Android with post parameters

You can actually send it as JSON the following way:

// Build the JSON object to pass parameters
JSONObject jsonObj = new JSONObject();
jsonObj.put("username", username);
jsonObj.put("apikey", apikey);
// Create the POST object and add the parameters
HttpPost httpPost = new HttpPost(url);
StringEntity entity = new StringEntity(jsonObj.toString(), HTTP.UTF_8);
HttpClient client = new DefaultHttpClient();
HttpResponse response = client.execute(httpPost);

Android Device not recognized by adb

With USB connected, on android device Settings > Developer options > Revoke USB debug authorizations USB Debug. Remove the USB and connect again, then "Allow USB debugging".

How to name and retrieve a stash by name in git?

git stash save is deprecated as of 2.15.x/2.16, instead you can use git stash push -m "message"

You can use it like this:

git stash push -m "message"

where "message" is your note for that stash.

In order to retrieve the stash you can use: git stash list. This will output a list like this, for example:

stash@{0}: On develop: perf-spike
stash@{1}: On develop: node v10

Then you simply use apply giving it the stash@{index}:

git stash apply stash@{1}

References git stash man page

<modules runAllManagedModulesForAllRequests="true" /> Meaning

Modules Preconditions:

The IIS core engine uses preconditions to determine when to enable a particular module. Performance reasons, for example, might determine that you only want to execute managed modules for requests that also go to a managed handler. The precondition in the following example (precondition="managedHandler") only enables the forms authentication module for requests that are also handled by a managed handler, such as requests to .aspx or .asmx files:

<add name="FormsAuthentication" type="System.Web.Security.FormsAuthenticationModule" preCondition="managedHandler" />

If you remove the attribute precondition="managedHandler", Forms Authentication also applies to content that is not served by managed handlers, such as .html, .jpg, .doc, but also for classic ASP (.asp) or PHP (.php) extensions. See "How to Take Advantage of IIS Integrated Pipeline" for an example of enabling ASP.NET modules to run for all content.

You can also use a shortcut to enable all managed (ASP.NET) modules to run for all requests in your application, regardless of the "managedHandler" precondition.

To enable all managed modules to run for all requests without configuring each module entry to remove the "managedHandler" precondition, use the runAllManagedModulesForAllRequests property in the <modules> section:

<modules runAllManagedModulesForAllRequests="true" />    

When you use this property, the "managedHandler" precondition has no effect and all managed modules run for all requests.

Copied from IIS Modules Overview: Preconditions

What is the boundary in multipart/form-data?

Is the ??? free to be defined by the user?


or is it supplied by the HTML?

No. HTML has nothing to do with that. Read below.

Is it possible for me to define the ??? as abcdefg?


If you want to send the following data to the web server:

name = John
age = 12

using application/x-www-form-urlencoded would be like this:


As you can see, the server knows that parameters are separated by an ampersand &. If & is required for a parameter value then it must be encoded.

So how does the server know where a parameter value starts and ends when it receives an HTTP request using multipart/form-data?

Using the boundary, similar to &.

For example:

Content-Disposition: form-data; name="name"

Content-Disposition: form-data; name="age"


In that case, the boundary value is XXX. You specify it in the Content-Type header so that the server knows how to split the data it receives.

So you need to:

  • Use a value that won't appear in the HTTP data sent to the server.

  • Be consistent and use the same value everywhere in the request message.

How do I create directory if it doesn't exist to create a file?

You can use File.Exists to check if the file exists and create it using File.Create if required. Make sure you check if you have access to create files at that location.

Once you are certain that the file exists, you can write to it safely. Though as a precaution, you should put your code into a try...catch block and catch for the exceptions that function is likely to raise if things don't go exactly as planned.

Additional information for basic file I/O concepts.

Disable browser cache for entire ASP.NET website

I know this answer is not 100% related to the question, but it might help someone.

If you want to disable the browser cache for the entire ASP.NET MVC Website, but you only want to do this TEMPORARILY, then it is better to disable the cache in your browser.

Here's a screenshot in Chrome

type object 'datetime.datetime' has no attribute 'datetime'

For python 3.3

from datetime import datetime, timedelta
futuredate = + timedelta(days=10)

How to import a module in Python with importlib.import_module

And don't forget to create a with each folder/subfolder (even if they are empty)

How might I find the largest number contained in a JavaScript array?

To find the largest number in an array you just need to use Math.max(...arrayName);. It works like this:

let myArr = [1, 2, 3, 4, 5, 6];

To learn more about Math.max:

Codeigniter displays a blank page instead of error messages

I had this same problem and as Shayan Husaini pointed out, I had an undetected syntax error.

I solved it using the php linter in the terminal:

php -l file.php

You can also use something like this to use the linter in every file in some folder:

find -type f -name "*.php" -exec php -l '{}' \;

And to filter just the ones with errors:

find -type f -name "*.php" -exec php -l '{}' \; | grep '^[^N]'

That should show files with parsing errors and the line where the error is.

Spring: return @ResponseBody "ResponseEntity<List<JSONObject>>"

Instead of

return new ResponseEntity<JSONObject>(entities, HttpStatus.OK);


return new ResponseEntity<List<JSONObject>>(entities, HttpStatus.OK);

Calculate the date yesterday in JavaScript

This will produce yesterday at 00:00 with minutes precision

var d = new Date();
d.setDate(d.getDate() - 1);

How do I write data to csv file in columns and rows from a list in python?

The provided examples, using csv modules, are great! Besides, you can always simply write to a text file using formatted strings, like the following tentative example:

l = [[1, 2], [2, 3], [4, 5]]

out = open('out.csv', 'w')
for row in l:
    for column in row:
        out.write('%d;' % column)

I used ; as separator, because it works best with Excell (one of your requirements).

Hope it helps!

Changing :hover to touch/click for mobile devices

On most devices, the other answers work. For me, to ensure it worked on every device (in react) I had to wrap it in an anchor tag <a> and add the following: :hover, :focus, :active (in that order), as well as role="button" and tabIndex="0".

In Excel, how do I extract last four letters of a ten letter string?

No need to use a macro. Supposing your first string is in A1.

=RIGHT(A1, 4)

Drag this down and you will get your four last characters.

Edit: To be sure, if you ever have sequences like 'ABC DEF' and want the last four LETTERS and not CHARACTERS you might want to use trimspaces()


Edit: As per brettdj's suggestion, you may want to check that your string is actually 4-character long or more:


Can not find module “@angular-devkit/build-angular”

I tried all the possible commands listed above and none of them worked for me, Check if Package.json contain "@angular-devkit/build-angular" if not just install it using(in my case version 0.803.19 worked)

npm i @angular-devkit/[email protected]

Or checkout at npm website repositories for version selection

Python: How to check if keys exists and retrieve value from Dictionary in descending priority

You can use myDict.has_key(keyname) as well to validate if the key exists.

Edit based on the comments -

This would work only on versions lower than 3.1. has_key has been removed from Python 3.1. You should use the in operator if you are using Python 3.1

scroll image with continuous scrolling using marquee tag

You cannot scroll images continuously using the HTML marquee tag - it must have JavaScript added for the continuous scrolling functionality.

There is a JavaScript plugin called crawler.js available on the dynamic drive forum for achieving this functionality. This plugin was created by John Davenport Scheuer and has been modified over time to suit new browsers.

I have also implemented this plugin into my blog to document all the steps to use this plugin. Here is the sample code:

    <script src="" type="text/javascript"></script>
    <script src="assets/js/crawler.js" type="text/javascript" ></script>

<div id="mycrawler2" style="margin-top: -3px; " class="productswesupport">
    <img src="assets/images/products/ie.png" />
    <img src="assets/images/products/browser.png" />
    <img src="assets/images/products/chrome.png" />
    <img src="assets/images/products/safari.png" />

Here is the plugin configration:

    uniqueid: 'mycrawler2',
    style: {
    inc: 5, //speed - pixel increment for each iteration of this marquee's movement
    mouse: 'cursor driven', //mouseover behavior ('pause' 'cursor driven' or false)
    moveatleast: 2,
    neutral: 150,
    savedirection: true,
    random: true

Bootstrap: Use .pull-right without having to hardcode a negative margin-top

just put #login-box before <h2>Welcome</h2> will be ok.

<div class='container'>
    <div class='hero-unit'>
        <div id='login-box' class='pull-right control-group'>
            <div class='clearfix'>
                <input type='text' placeholder='Username' />
            <div class='clearfix'>
                <input type='password' placeholder='Password' />
            <button type='button' class='btn btn-primary'>Log in</button>

        <p>Please log in</p>


here is jsfiddle

Declaring variables inside loops, good practice or bad practice?

Chapter 4.8 Block Structure in K&R's The C Programming Language 2.Ed.:

An automatic variable declared and initialized in a block is initialized each time the block is entered.

I might have missed seeing the relevant description in the book like:

An automatic variable declared and initialized in a block is allocated only one time before the block is entered.

But a simple test can prove the assumption held:

 #include <stdio.h>                                                                                                    

 int main(int argc, char *argv[]) {                                                                                    
     for (int i = 0; i < 2; i++) {                                                                                     
         for (int j = 0; j < 2; j++) {                                                                                 
             int k;                                                                                                    
             printf("%p\n", &k);                                                                                       
     return 0;                                                                                                         

"The system cannot find the file specified"

I had the same problem - for me it was the SQL Server running out of memory. Freeing up some memory solved the issue

How to set default value for column of new created table from select statement in 11g

You will need to alter table abc modify (salary default 0);

How to make a div 100% height of the browser window

.wrapper {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -ms-flex-wrap: wrap;
  flex-wrap: wrap;
  height: 100vh; // Height window (vh)
.wrapper .left{
  width: 80%; // Width optional, but recommended
.wrapper .right{
  width: 20%; // Width optional, but recommended
  background-color: #dd1f26;
vw: hundredths of the viewport width.
vh: hundredths of the viewport height.
vmin: hundredths of whichever is smaller, the viewport width or height.
vmax: hundredths of whichever is larger, the viewport width or height.
<div class="wrapper">
  <div class="left">
  <div class="right">

Open a folder using Process.Start

Use an overloaded version of the method that takes a ProcessStartInfo instance and set the ProcessWindowStyle property to a value that works for you.

Open and write data to text file using Bash?


cat > FILE.txt <<EOF

info code info 
info code info
info code info


Copy array items into another array

The function below doesn't have an issue with the length of arrays and performs better than all suggested solutions:

function pushArray(list, other) {
    var len = other.length;
    var start = list.length;
    list.length = start + len;
    for (var i = 0; i < len; i++ , start++) {
        list[start] = other[i];

unfortunately, jspref refuses to accept my submissions, so here they are the results using benchmark.js

        Name            |   ops/sec   |  ± %  | runs sampled
for loop and push       |      177506 |  0.92 | 63
Push Apply              |      234280 |  0.77 | 66
spread operator         |      259725 |  0.40 | 67
set length and for loop |      284223 |  0.41 | 66


for loop and push is:

    for (var i = 0, l = source.length; i < l; i++) {

Push Apply:

target.push.apply(target, source);

spread operator:


and finally the 'set length and for loop' is the above function

How to implement __iter__(self) for a container object (Python)

In case you don't want to inherit from dict as others have suggested, here is direct answer to the question on how to implement __iter__ for a crude example of a custom dict:

class Attribute:
    def __init__(self, key, value):
        self.key = key
        self.value = value

class Node(collections.Mapping):
    def __init__(self):
        self.type  = ""
        self.attrs = [] # List of Attributes

    def __iter__(self):
        for attr in self.attrs:
            yield attr.key

That uses a generator, which is well described here.

Since we're inheriting from Mapping, you need to also implement __getitem__ and __len__:

    def __getitem__(self, key):
        for attr in self.attrs:
            if key == attr.key:
                return attr.value
        raise KeyError

    def __len__(self):
        return len(self.attrs)

How to combine two or more querysets in a Django view?

Concatenating the querysets into a list is the simplest approach. If the database will be hit for all querysets anyway (e.g. because the result needs to be sorted), this won't add further cost.

from itertools import chain
result_list = list(chain(page_list, article_list, post_list))

Using itertools.chain is faster than looping each list and appending elements one by one, since itertools is implemented in C. It also consumes less memory than converting each queryset into a list before concatenating.

Now it's possible to sort the resulting list e.g. by date (as requested in hasen j's comment to another answer). The sorted() function conveniently accepts a generator and returns a list:

result_list = sorted(
    chain(page_list, article_list, post_list),
    key=lambda instance: instance.date_created)

If you're using Python 2.4 or later, you can use attrgetter instead of a lambda. I remember reading about it being faster, but I didn't see a noticeable speed difference for a million item list.

from operator import attrgetter
result_list = sorted(
    chain(page_list, article_list, post_list),

How to update and order by using ms sql

UPDATE messages SET 
WHERE ID in (SELECT TOP (10) Id FROM Table WHERE status=0 ORDER BY priority DESC);

How can I get all the request headers in Django?

I don't think there is any easy way to get only HTTP headers. You have to iterate through request.META dict to get what all you need.

django-debug-toolbar takes the same approach to show header information. Have a look at this file responsible for retrieving header information.

SQL Server - Convert date field to UTC

Here's my quick and dirty version. I know all of my dates were using the US Eastern time zone. You can change the offset or otherwise make it smarter as you need to. I was doing a one-time migration so this was Good Enough.

CREATE FUNCTION [dbo].[ConvertToUtc]
    @date datetime
    -- Declare the return variable here
    DECLARE @utcDate datetime;
    DECLARE @offset int;

    SET @offset = (SELECT CASE WHEN 
                                    @date BETWEEN '1987-04-05 02:00 AM' AND '1987-10-25 02:00 AM'
                                 OR @date BETWEEN '1988-04-03 02:00 AM' AND '1988-10-30 02:00 AM'
                                 OR @date BETWEEN '1989-04-02 02:00 AM' AND '1989-10-29 02:00 AM'
                                 OR @date BETWEEN '1990-04-01 02:00 AM' AND '1990-10-28 02:00 AM'
                                 OR @date BETWEEN '1991-04-07 02:00 AM' AND '1991-10-27 02:00 AM'
                                 OR @date BETWEEN '1992-04-05 02:00 AM' AND '1992-10-25 02:00 AM'
                                 OR @date BETWEEN '1993-04-04 02:00 AM' AND '1993-10-31 02:00 AM'
                                 OR @date BETWEEN '1994-04-03 02:00 AM' AND '1994-10-30 02:00 AM'
                                 OR @date BETWEEN '1995-04-02 02:00 AM' AND '1995-10-29 02:00 AM'
                                 OR @date BETWEEN '1996-04-07 02:00 AM' AND '1996-10-27 02:00 AM'
                                 OR @date BETWEEN '1997-04-06 02:00 AM' AND '1997-10-26 02:00 AM'
                                 OR @date BETWEEN '1998-04-05 02:00 AM' AND '1998-10-25 02:00 AM'
                                 OR @date BETWEEN '1999-04-04 02:00 AM' AND '1999-10-31 02:00 AM'
                                 OR @date BETWEEN '2000-04-02 02:00 AM' AND '2000-10-29 02:00 AM'
                                 OR @date BETWEEN '2001-04-01 02:00 AM' AND '2001-10-28 02:00 AM'
                                 OR @date BETWEEN '2002-04-07 02:00 AM' AND '2002-10-27 02:00 AM'
                                 OR @date BETWEEN '2003-04-06 02:00 AM' AND '2003-10-26 02:00 AM'
                                 OR @date BETWEEN '2004-04-04 02:00 AM' AND '2004-10-31 02:00 AM'
                                 OR @date BETWEEN '2005-04-03 02:00 AM' AND '2005-10-30 02:00 AM'
                                 OR @date BETWEEN '2006-04-02 02:00 AM' AND '2006-10-29 02:00 AM'
                                 OR @date BETWEEN '2007-03-11 02:00 AM' AND '2007-11-04 02:00 AM'
                                 OR @date BETWEEN '2008-03-09 02:00 AM' AND '2008-11-02 02:00 AM'
                                 OR @date BETWEEN '2009-03-08 02:00 AM' AND '2009-11-01 02:00 AM'
                                 OR @date BETWEEN '2010-03-14 02:00 AM' AND '2010-11-07 02:00 AM'
                                 OR @date BETWEEN '2011-03-13 02:00 AM' AND '2011-11-06 02:00 AM'
                                 OR @date BETWEEN '2012-03-11 02:00 AM' AND '2012-11-04 02:00 AM'
                                 OR @date BETWEEN '2013-03-10 02:00 AM' AND '2013-11-03 02:00 AM'
                                 OR @date BETWEEN '2014-03-09 02:00 AM' AND '2014-11-02 02:00 AM'
                                 OR @date BETWEEN '2015-03-08 02:00 AM' AND '2015-11-01 02:00 AM'
                                 OR @date BETWEEN '2016-03-13 02:00 AM' AND '2016-11-06 02:00 AM'
                                 OR @date BETWEEN '2017-03-12 02:00 AM' AND '2017-11-05 02:00 AM'
                                 OR @date BETWEEN '2018-03-11 02:00 AM' AND '2018-11-04 02:00 AM'
                                 OR @date BETWEEN '2019-03-10 02:00 AM' AND '2019-11-03 02:00 AM'
                                 OR @date BETWEEN '2020-03-08 02:00 AM' AND '2020-11-01 02:00 AM'
                                 OR @date BETWEEN '2021-03-14 02:00 AM' AND '2021-11-07 02:00 AM'
                               THEN 4
                               ELSE 5 END);

    SELECT @utcDate = DATEADD(hh, @offset, @date)
    RETURN @utcDate;


Use grep --exclude/--include syntax to not grep through certain files

those scripts don't accomplish all the problem...Try this better:

du -ha | grep -i -o "\./.*" | grep -v "\.svn\|another_file\|another_folder" | xargs grep -i -n "$1"

this script is so better, because it uses "real" regular expressions to avoid directories from search. just separate folder or file names with "\|" on the grep -v

enjoy it! found on my linux shell! XD

My httpd.conf is empty

The /etc/apache2/httpd.conf is empty in Ubuntu, because the Apache configuration resides in /etc/apache2/apache2.conf!

“httpd.conf is for user options.” No it isn't, it's there for historic reasons.

Using Apache server, all user options should go into a new *.conf-file inside /etc/apache2/conf.d/. This method should be "update-safe", as httpd.conf or apache2.conf may get overwritten on the next server update.

Inside /etc/apache2/apache2.conf, you will find the following line, which includes those files:

# Include generic snippets of statements
Include conf.d/

As of Apache 2.4+ the user configuration directory is /etc/apache2/conf-available/. Use a2enconf FILENAME_WITHOUT_SUFFIX to enable the new configuration file or manually create a symlink in /etc/apache2/conf-enabled/. Be aware that as of Apache 2.4 the configuration files must have the suffix .conf (e.g. conf-available/my-settings.conf);

How to check if a variable is not null?

The two conditional statements you list here are not better than one another. Your usage depends on the situation. You have a typo by the way in the 2nd example. There should be only one equals sign after the exclamation mark.

The 1st example determines if the value in myVar is true and executes the code inside of the {...}

The 2nd example evaluates if myVar does not equal null and if that case is true it will execute your code inside of the {...}

I suggest taking a look into conditional statements for more techniques. Once you are familiar with them, you can decide when you need them.

How to check if a column exists in Pandas

To check if one or more columns all exist, you can use set.issubset, as in:

if set(['A','C']).issubset(df.columns):
   df['sum'] = df['A'] + df['C']                

As @brianpck points out in a comment, set([]) can alternatively be constructed with curly braces,

if {'A', 'C'}.issubset(df.columns):

See this question for a discussion of the curly-braces syntax.

Or, you can use a list comprehension, as in:

if all([item in df.columns for item in ['A','C']]):

iOS - Calling App Delegate method from ViewController

Sounds like you just need a UINavigationController setup?

You can get the AppDelegate anywhere in the program via

YourAppDelegateName* blah = (YourAppDelegateName*)[[UIApplication sharedApplication]delegate];

In your app delegate you should have your navigation controller setup, either via IB or in code.

In code, assuming you've created your 'House overview' viewcontroller already it would be something like this in your AppDelegate didFinishLaunchingWithOptions...

self.m_window = [[[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds] autorelease];
self.m_navigationController = [[[UINavigationController alloc]initWithRootViewController:homeViewController]autorelease];
[m_window addSubview:self.m_navigationController.view];

After this you just need a viewcontroller per 'room' and invoke the following when a button click event is picked up...

YourAppDelegateName* blah = (YourAppDelegateName*)[[UIApplication sharedApplication]delegate];
[blah.m_navigationController pushViewController:newRoomViewController animated:YES];

I've not tested the above code so forgive any syntax errors but hope the pseudo code is of help...

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

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

Make a table fill the entire window

This works fine for me:

<style type="text/css">_x000D_
#table {_x000D_
 position: absolute;_x000D_
 top: 0;_x000D_
 bottom: 0;_x000D_
 left: 0;_x000D_
 right: 0;_x000D_
 height: 100%;_x000D_
 width: 100%;_x000D_

For me, just changing Height and Width to 100% doesn’t do it for me, and neither do setting left, right, top and bottom to 0, but using them both together will do the trick.

How to add new contacts in android

These examples are fine, I wanted to point out that you can achieve the same result using an Intent. The intent opens the Contacts app with the fields you provide already filled in.

It's up to the user to save the newly created contact.

You can read about it here:

Intent contactIntent = new Intent(ContactsContract.Intents.Insert.ACTION);

        .putExtra(ContactsContract.Intents.Insert.NAME, "Contact Name")
        .putExtra(ContactsContract.Intents.Insert.PHONE, "5555555555");

startActivityForResult(contactIntent, 1);

startActivityForResult() gives you the opportunity to see the result.

I've noticed the resultCode works on >5.0 devices,

but I have an older Samsung (<5) that always returns RESULT_CANCELLED (0).

Which I understand is the default return if an activity doesn't expect to return anything.

protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);

    if (requestCode == 1)
        if (resultCode == Activity.RESULT_OK) {
            Toast.makeText(this, "Added Contact", Toast.LENGTH_SHORT).show();
        if (resultCode == Activity.RESULT_CANCELED) {
            Toast.makeText(this, "Cancelled Added Contact", Toast.LENGTH_SHORT).show();

postgresql sequence nextval in schema

SELECT last_value, increment_by from "other_schema".id_seq;

for adding a seq to a column where the schema is not public try this.


ORA-03113: end-of-file on communication channel after long inactivity in ASP.Net app

end-of-file on communication channel:

One of the course of this error is due to database fail to write the log when its in the stage of opening;

Solution check the database if its running in ARCHIVELOG or NOARCHIVELOG

to check use

select log_mode from v$database;

if its on ARCHIVELOG try to change into NOARCHIVELOG

by using sqlplus

  • startup mount
  • alter database noarchivelog;
  • alter database open;

if it works for this

Then you can adjust your flashrecovery area its possibly that your flashrecovery area is full -> then after confirm that your flashrecovery area has the space you can alter your database into the ARCHIVELOG

Installing the Android USB Driver in Windows 7

Just download and install "Samsung Kies" from this link. and everything would work as required.

Before installing, uninstall the drivers you have installed for your device.


Two possible solutions:

  1. Try with the Google USB driver which comes with the SDK.
  2. Download and install the Samsung USB driver from this link as suggested by Mauricio Gracia Gutierrez

How can I create 2 separate log files with one log4j config file?

Try the following configuration:

log4j.rootLogger=TRACE, stdout

log4j.appender.stdout.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n

log4j.appender.debugLog.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n

log4j.appender.reportsLog.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n

log4j.category.debugLogger=TRACE, debugLog

log4j.category.reportsLogger=DEBUG, reportsLog

Then configure the loggers in the Java code accordingly:

static final Logger debugLog = Logger.getLogger("debugLogger");
static final Logger resultLog = Logger.getLogger("reportsLogger");

Do you want output to go to stdout? If not, change the first line of to:


and get rid of the stdout lines.

Regular expression to match a line that doesn't contain a word

Note that the solution to does not start with “hede”:


is generally much more efficient than the solution to does not contain “hede”:


The former checks for “hede” only at the input string’s first position, rather than at every position.

No == operator found while comparing structs in C++

Starting in C++20, it should be possible to add a full set of default comparison operators (==, <=, etc.) to a class by declaring a default three-way comparison operator ("spaceship" operator), like this:

struct Point {
    int x;
    int y;
    auto operator<=>(const Point&) const = default;

With a compliant C++20 compiler, adding that line to MyStruct1 and MyStruct2 may be enough to allow equality comparisons, assuming the definition of MyStruct2 is compatible.

How to display string that contains HTML in twig template?

{{ word|striptags('<b>,<a>,<pre>')|raw }}

if you want to allow multiple tags

Forbidden: You don't have permission to access / on this server, WAMP Error

I find the best (and least frustrating) path is to start with Allow from All, then, when you know it will work that way, scale it back to the more secure Allow from or Allow from ::1 (localhost).

As long as your firewall is configured properly, Allow from all shouldn't cause any problems, but it is better to only allow from localhost if you don't need other computers to be able to access your site.

Don't forget to restart Apache whenever you make changes to httpd.conf. They will not take effect until the next start.

Hopefully this is enough to get you started, there is lots of documentation available online.

How to convert R Markdown to PDF?

I found using R studio the easiest way, but if wanting to control from the command line, then a simple R script can do the trick using rmarkdown render command (as mentioned above). Full script details here

#!/usr/bin/env R

# Render R markdown to PDF.
# Invoke with:
# > R -q -f make.R --args my_report.Rmd

# load packages

# require a parameter naming file to render
if (length(args) == 0) {
    stop("Error: missing file operand", call. = TRUE)
} else {
    # read report to render from command line
    for (rmd in commandArgs(trailingOnly = TRUE)) {
        # render Rmd to PDF
        if ( grepl("\\.Rmd$", rmd) && file.exists(rmd)) {
            render(rmd, pdf_document())
        } else {
            print(paste("Ignoring: ", rmd))

Best practice to call ConfigureAwait for all server-side code

Update: ASP.NET Core does not have a SynchronizationContext. If you are on ASP.NET Core, it does not matter whether you use ConfigureAwait(false) or not.

For ASP.NET "Full" or "Classic" or whatever, the rest of this answer still applies.

Original post (for non-Core ASP.NET):

This video by the ASP.NET team has the best information on using async on ASP.NET.

I had read that it is more performant since it doesn't have to switch thread contexts back to the original thread context.

This is true with UI applications, where there is only one UI thread that you have to "sync" back to.

In ASP.NET, the situation is a bit more complex. When an async method resumes execution, it grabs a thread from the ASP.NET thread pool. If you disable the context capture using ConfigureAwait(false), then the thread just continues executing the method directly. If you do not disable the context capture, then the thread will re-enter the request context and then continue to execute the method.

So ConfigureAwait(false) does not save you a thread jump in ASP.NET; it does save you the re-entering of the request context, but this is normally very fast. ConfigureAwait(false) could be useful if you're trying to do a small amount of parallel processing of a request, but really TPL is a better fit for most of those scenarios.

However, with ASP.NET Web Api, if your request is coming in on one thread, and you await some function and call ConfigureAwait(false) that could potentially put you on a different thread when you are returning the final result of your ApiController function.

Actually, just doing an await can do that. Once your async method hits an await, the method is blocked but the thread returns to the thread pool. When the method is ready to continue, any thread is snatched from the thread pool and used to resume the method.

The only difference ConfigureAwait makes in ASP.NET is whether that thread enters the request context when resuming the method.

I have more background information in my MSDN article on SynchronizationContext and my async intro blog post.

C# binary literals

You can use 0b000001 since Visual Studio 2017 (C# 7.0)

src absolute path problem

<img src="file://C:/wamp/www/site/img/mypicture.jpg"/>

How can I rename a conda environment?

conda should have given us a simple tool like cond env rename <old> <new> but it hasn't. Simply renaming the directory, as in this previous answer, of course, breaks the hardcoded hashbangs(#!). Hence, we need to go one more level deeper to achieve what we want.

conda env list
# conda environments:
base                  *  /home/tgowda/miniconda3
junkdetect               /home/tgowda/miniconda3/envs/junkdetect
rtg                      /home/tgowda/miniconda3/envs/rtg

Here I am trying to rename rtg --> unsup (please bear with those names, this is my real use case)

$ cd /home/tgowda/miniconda3/envs 
$ OLD=rtg
$ NEW=unsup
$ mv $OLD $NEW   # rename dir

$ conda env list
# conda environments:
base                  *  /home/tgowda/miniconda3
junkdetect               /home/tgowda/miniconda3/envs/junkdetect
unsup                    /home/tgowda/miniconda3/envs/unsup

$ conda activate $NEW
$ which python

the previous answer reported upto this, but wait, we are not done yet! the pending task is, $NEW/bin dir has a bunch of executable scripts with hashbangs (#!) pointing to the $OLD env paths.

See jupyter, for example:

$ which jupyter

$ head -1 $(which jupyter) # its hashbang is still looking at old

So, we can easily fix it with a sed

$ sed  -i.bak "s:envs/$OLD/bin:envs/$NEW/bin:" $NEW/bin/*  
# `-i.bak` created backups, to be safe

$ head -1 $(which jupyter) # check if updated
$ jupyter --version # check if it works
jupyter core     : 4.6.3
jupyter-notebook : 6.0.3

$ rm $NEW/bin/*.bak  # remove backups

Now we are done

I think it should be trivial to write a portable script to do all those and bind it to conda env rename old new.

I tested this on ubuntu. For whatever unforseen reasons, if things break and you wish to revert the above changes:

$ mv $NEW  $OLD
$ sed  -i.bak "s:envs/$NEW/bin:envs/$OLD/bin:" $OLD/bin/*

Chmod recursively

To make everything writable by the owner, read/execute by the group, and world executable:

chmod -R 0755

To make everything wide open:

chmod -R 0777

adding noise to a signal in python

For those who want to add noise to a multi-dimensional dataset loaded within a pandas dataframe or even a numpy ndarray, here's an example:

import pandas as pd
# create a sample dataset with dimension (2,2)
# in your case you need to replace this with 
# clean_signal = pd.read_csv("your_data.csv")   
clean_signal = pd.DataFrame([[1,2],[3,4]], columns=list('AB'), dtype=float) 
print output: 
    A    B
0  1.0  2.0
1  3.0  4.0
import numpy as np 
mu, sigma = 0, 0.1 
# creating a noise with the same dimension as the dataset (2,2) 
noise = np.random.normal(mu, sigma, [2,2]) 

print output: 
array([[-0.11114313,  0.25927152],
       [ 0.06701506, -0.09364186]])
signal = clean_signal + noise
print output: 
          A         B
0  0.888857  2.259272
1  3.067015  3.906358

async/await - when to return a Task vs void?

1) Normally, you would want to return a Task. The main exception should be when you need to have a void return type (for events). If there's no reason to disallow having the caller await your task, why disallow it?

2) async methods that return void are special in another aspect: they represent top-level async operations, and have additional rules that come into play when your task returns an exception. The easiest way is to show the difference is with an example:

static async void f()
    await h();

static async Task g()
    await h();

static async Task h()
    throw new NotImplementedException();

private void button1_Click(object sender, EventArgs e)

private void button2_Click(object sender, EventArgs e)

private void button3_Click(object sender, EventArgs e)

f's exception is always "observed". An exception that leaves a top-level asynchronous method is simply treated like any other unhandled exception. g's exception is never observed. When the garbage collector comes to clean up the task, it sees that the task resulted in an exception, and nobody handled the exception. When that happens, the TaskScheduler.UnobservedTaskException handler runs. You should never let this happen. To use your example,

public static async void AsyncMethod2(int num)
    await Task.Factory.StartNew(() => Thread.Sleep(num));

Yes, use async and await here, they make sure your method still works correctly if an exception is thrown.

for more information see:

How to get the current time in Python


from time import time

t = time()
  • t - float number, good for time interval measurement.

There is some difference for Unix and Windows platforms.

HTML img tag: title attribute vs. alt attribute?

The MVCFutures for ASP.NET MVC decided to do both. In fact if you provide 'alt' it will automatically create a 'title' with the same value for you.

I don't have the source code to hand but a quick google search turned up a test case for it!

    public void ImageWithAltValueInObjectDictionaryRendersImageWithAltAndTitleTag() {
        HtmlHelper html = TestHelper.GetHtmlHelper(new ViewDataDictionary());
        string imageResult = html.Image("/system/web/mvc.jpg", new { alt = "this is an alt value" });
        Assert.AreEqual("<img alt=\"this is an alt value\" src=\"/system/web/mvc.jpg\" title=\"this is an alt value\" />", imageResult);

GROUP BY + CASE statement

Try adding the other two non COUNT columns to the GROUP BY:

select CURRENT_DATE-1 AS day,, 
CASE WHEN attempt.result = 0 THEN 0 ELSE 1 END, 
from attempt attempt, prod_hw_id prod_hw_id, model model
where time >= '2013-11-06 00:00:00'  
AND time < '2013-11-07 00:00:00'
AND attempt.hard_id = prod_hw_id.hard_id
AND prod_hw_id.model_id = model.model_id
group by 1,2,3,4
order by, attempt.type, attempt.result;

How do I run git log to see changes only for a specific branch?

The problem I was having, which I think is similar to this, is that master was too far ahead of my branch point for the history to be useful. (Navigating to the branch point would take too long.)

After some trial and error, this gave me roughly what I wanted:

git log --graph --decorate --oneline --all ^master^!

Uncaught SyntaxError: Invalid or unexpected token

The accepted answer work when you have a single line string(the email) but if you have a

multiline string, the error will remain.

Please look into this matter:

<!-- start: definition-->
    dynamic item = new System.Dynamic.ExpandoObject();
    item.MultiLineString = @"a multi-line
    item.SingleLineString = "a single-line string";
<!-- end: definition-->
<a href="#" onclick="Getinfo('@item.MultiLineString')">6/16/2016 2:02:29 AM</a>
    function Getinfo(text) {

Change the single-quote(') to backtick(`) in Getinfo as bellow and error will be fixed:

<a href="#" onclick="Getinfo(`@item.MultiLineString`)">6/16/2016 2:02:29 AM</a>

Compile c++14-code with g++

For gcc 4.8.4 you need to use -std=c++1y in later versions, looks like starting with 5.2 you can use -std=c++14.

If we look at the gcc online documents we can find the manuals for each version of gcc and we can see by going to Dialect options for 4.9.3 under the GCC 4.9.3 manual it says:


The next revision of the ISO C++ standard, tentatively planned for 2014. Support is highly experimental, and will almost certainly change in incompatible ways in future releases.

So up till 4.9.3 you had to use -std=c++1y while the gcc 5.2 options say:

‘c++14’ ‘c++1y’

The 2014 ISO C++ standard plus amendments. The name ‘c++1y’ is deprecated.

It is not clear to me why this is listed under Options Controlling C Dialect but that is how the documents are currently organized.

How to generate a QR Code for an Android application?

I used zxing-1.3 jar and I had to make some changes implementing code from other answers, so I will leave my solution for others. I did the following:

1) find zxing-1.3.jar, download it and add in properties (add external jar).

2) in my activity layout add ImageView and name it (in my example it was tnsd_iv_qr).

3) include code in my activity to create qr image (in this example I was creating QR for bitcoin payments):

    QRCodeWriter writer = new QRCodeWriter();
    ImageView tnsd_iv_qr = (ImageView)findViewById(;
    try {
        ByteMatrix bitMatrix = writer.encode("bitcoin:"+btc_acc_adress+"?amount="+amountBTC, BarcodeFormat.QR_CODE, 512, 512);
        int width = 512;
        int height = 512;
        Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                if (bitMatrix.get(x, y)==0)
                    bmp.setPixel(x, y, Color.BLACK);
                    bmp.setPixel(x, y, Color.WHITE);
    } catch (WriterException e) {
        //Log.e("QR ERROR", ""+e);


If someone is wondering, variable "btc_acc_adress" is a String (with BTC adress), amountBTC is a double, with, of course, transaction amount.

How to find the nearest parent of a Git branch?

vbc=$(git rev-parse --abbrev-ref HEAD)
vbc_col=$(( $(git show-branch | grep '^[^\[]*\*' | head -1 | cut -d* -f1 | wc -c) - 1 )) 
swimming_lane_start_row=$(( $(git show-branch | grep -n "^[\-]*$" | cut -d: -f1) + 1 )) 
git show-branch | tail -n +$swimming_lane_start_row | grep -v "^[^\[]*\[$vbc" | grep "^.\{$vbc_col\}[^ ]" | head -n1 | sed 's/.*\[\(.*\)\].*/\1/' | sed 's/[\^~].*//'

Achieves the same ends as Mark Reed's answer, but uses a much safer approach that doesn't misbehave in a number of scenarios:

  1. Parent branch's last commit is a merge, making the column show - not *
  2. Commit message contains branch name
  3. Commit message contains *

Hiding elements in responsive layout?

In boostrap 4.1 (run snippet because I copied whole table code from Bootstrap documentation):

.fixed_headers {_x000D_
  width: 750px;_x000D_
  table-layout: fixed;_x000D_
  border-collapse: collapse;_x000D_
.fixed_headers th {_x000D_
  text-decoration: underline;_x000D_
.fixed_headers th,_x000D_
.fixed_headers td {_x000D_
  padding: 5px;_x000D_
  text-align: left;_x000D_
.fixed_headers td:nth-child(1),_x000D_
.fixed_headers th:nth-child(1) {_x000D_
  min-width: 200px;_x000D_
.fixed_headers td:nth-child(2),_x000D_
.fixed_headers th:nth-child(2) {_x000D_
  min-width: 200px;_x000D_
.fixed_headers td:nth-child(3),_x000D_
.fixed_headers th:nth-child(3) {_x000D_
  width: 350px;_x000D_
.fixed_headers thead {_x000D_
  background-color: #333;_x000D_
  color: #FDFDFD;_x000D_
.fixed_headers thead tr {_x000D_
  display: block;_x000D_
  position: relative;_x000D_
.fixed_headers tbody {_x000D_
  display: block;_x000D_
  overflow: auto;_x000D_
  width: 100%;_x000D_
  height: 300px;_x000D_
.fixed_headers tbody tr:nth-child(even) {_x000D_
  background-color: #DDD;_x000D_
.old_ie_wrapper {_x000D_
  height: 300px;_x000D_
  width: 750px;_x000D_
  overflow-x: hidden;_x000D_
  overflow-y: auto;_x000D_
.old_ie_wrapper tbody {_x000D_
  height: auto;_x000D_
<table class="fixed_headers">_x000D_
      <th>Screen Size</th>_x000D_
      <td>Hidden on all</td>_x000D_
      <td><code class="highlighter-rouge">.d-none</code></td>_x000D_
      <td>Hidden only on xs</td>_x000D_
      <td><code class="highlighter-rouge">.d-none .d-sm-block</code></td>_x000D_
      <td>Hidden only on sm</td>_x000D_
      <td><code class="highlighter-rouge">.d-sm-none .d-md-block</code></td>_x000D_
      <td>Hidden only on md</td>_x000D_
      <td><code class="highlighter-rouge">.d-md-none .d-lg-block</code></td>_x000D_
      <td>Hidden only on lg</td>_x000D_
      <td><code class="highlighter-rouge">.d-lg-none .d-xl-block</code></td>_x000D_
      <td>Hidden only on xl</td>_x000D_
      <td><code class="highlighter-rouge">.d-xl-none</code></td>_x000D_
      <td>Visible on all</td>_x000D_
      <td><code class="highlighter-rouge">.d-block</code></td>_x000D_
      <td>Visible only on xs</td>_x000D_
      <td><code class="highlighter-rouge">.d-block .d-sm-none</code></td>_x000D_
      <td>Visible only on sm</td>_x000D_
      <td><code class="highlighter-rouge">.d-none .d-sm-block .d-md-none</code></td>_x000D_
      <td>Visible only on md</td>_x000D_
      <td><code class="highlighter-rouge">.d-none .d-md-block .d-lg-none</code></td>_x000D_
      <td>Visible only on lg</td>_x000D_
      <td><code class="highlighter-rouge">.d-none .d-lg-block .d-xl-none</code></td>_x000D_
      <td>Visible only on xl</td>_x000D_
      <td><code class="highlighter-rouge">.d-none .d-xl-block</code></td>_x000D_

How to change the colors of a PNG image easily?

Use Photoshop, Paint.NET or similar software and adjust Hue.

Python 101: Can't open file: No such file or directory

Try uninstalling Python and then install it again, but this time make sure that the option Add Python to Path is marked as checked during the installation process.

SecurityError: Blocked a frame with origin from accessing a cross-origin frame

  • Open the start menu
  • Type windows+R or open "Run
  • Execute the following command.

chrome.exe --user-data-dir="C://Chrome dev session" --disable-web-security

How to remove an element from the flow?

Floating it will reorganise the flow but position: absolute is the only way to completely remove it from the flow of the document.

Convert System.Drawing.Color to RGB and Hex Value



This can avoid the KnownColor trick.

Android: How do I prevent the soft keyboard from pushing my view up?


This one is working for me.

Why is Thread.Sleep so harmful

I agree with many here, but I also think it depends.

Recently I did this code:

private void animate(FlowLayoutPanel element, int start, int end)
    bool asc = end > start;
    while (start != end) {
        start += asc ? 1 : -1;
        element.Height = start;
    if (!asc)

It was a simple animate-function, and I used Thread.Sleep on it.

My conclusion, if it does the job, use it.

Check file uploaded is in csv format

So I ran into this today.

Was attempting to validate an uploaded CSV file's MIME type by looking at $_FILES['upload_file']['type'], but for certain users on various browsers (and not necessarily the same browsers between said users; for instance it worked fine for me in FF but for another user it didn't work on FF) the $_FILES['upload_file']['type'] was coming up as "application/" instead of the expected "text/csv" or "text/plain".

So I resorted to using the (IMHO) much more reliable finfo_* functions something like this:

$acceptable_mime_types = array('text/plain', 'text/csv', 'text/comma-separated-values');

if (!empty($_FILES) && array_key_exists('upload_file', $_FILES) && $_FILES['upload_file']['error'] == UPLOAD_ERR_OK) {
    $tmpf = $_FILES['upload_file']['tmp_name'];

    // Make sure $tmpf is kosher, then:

    $finfo = finfo_open(FILEINFO_MIME_TYPE);
    $mime_type = finfo_file($finfo, $tmpf);

    if (!in_array($mime_type, $acceptable_mime_types)) {
        // Unacceptable mime type.

Convert boolean result into number/integer

if you want integer x value change if 1 to 0 and if 0 to 1 you can use (x + 1) % 2

Representing Directory & File Structure in Markdown Syntax

I made a node module to automate this task: mddir


node mddir "../relative/path/"

To install: npm install mddir -g

To generate markdown for current directory: mddir

To generate for any absolute path: mddir /absolute/path

To generate for a relative path: mddir ~/Documents/whatever.

The md file gets generated in your working directory.

Currently ignores node_modules, and .git folders.


If you receive the error 'node\r: No such file or directory', the issue is that your operating system uses different line endings and mddir can't parse them without you explicitly setting the line ending style to Unix. This usually affects Windows, but also some versions of Linux. Setting line endings to Unix style has to be performed within the mddir npm global bin folder.

Line endings fix

Get npm bin folder path with:

npm config get prefix

Cd into that folder

brew install dos2unix

dos2unix lib/node_modules/mddir/src/mddir.js

This converts line endings to Unix instead of Dos

Then run as normal with: node mddir "../relative/path/".

Example generated markdown file structure ''

    |-- .bowerrc
    |-- .jshintrc
    |-- .jshintrc2
    |-- Gruntfile.js
    |-- bower.json
    |-- karma.conf.js
    |-- package.json
    |-- app
        |-- app.js
        |-- db.js
        |-- index.html
        |-- mddir.js
        |-- routing.js
        |-- server.js
        |-- _api
            |-- api.groups.js
            |-- api.posts.js
            |-- api.users.js
            |-- api.widgets.js
        |-- _components
            |-- directives
                |-- directives.module.js
                |-- vendor
                    |-- directive.draganddrop.js
            |-- helpers
                |-- helpers.module.js
                |-- proprietary
                    |-- factory.actionDispatcher.js
            |-- services
                |-- services.cardTemplates.js
                |-- services.groups.js
                |-- services.posts.js
                |-- services.users.js
                |-- services.widgets.js
        |-- _mocks
            |-- mocks.groups.js
            |-- mocks.posts.js
            |-- mocks.users.js
            |-- mocks.widgets.js

Jinja2 shorthand conditional

Alternative way (but it's not python style. It's JS style)

{{ files and 'Update' or 'Continue' }}

Save a subplot in matplotlib

While @Eli is quite correct that there usually isn't much of a need to do it, it is possible. savefig takes a bbox_inches argument that can be used to selectively save only a portion of a figure to an image.

Here's a quick example:

import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np

# Make an example plot with two subplots...
fig = plt.figure()
ax1 = fig.add_subplot(2,1,1)
ax1.plot(range(10), 'b-')

ax2 = fig.add_subplot(2,1,2)
ax2.plot(range(20), 'r^')

# Save the full figure...

# Save just the portion _inside_ the second axis's boundaries
extent = ax2.get_window_extent().transformed(fig.dpi_scale_trans.inverted())
fig.savefig('ax2_figure.png', bbox_inches=extent)

# Pad the saved area by 10% in the x-direction and 20% in the y-direction
fig.savefig('ax2_figure_expanded.png', bbox_inches=extent.expanded(1.1, 1.2))

The full figure: Full Example Figure

Area inside the second subplot: Inside second subplot

Area around the second subplot padded by 10% in the x-direction and 20% in the y-direction: Full second subplot

How to access PHP variables in JavaScript or jQuery rather than <?php echo $variable ?>

Basically, yes. You write alert('<?php echo($phpvariable); ?>');

There are sure other ways to interoperate, but none of which i can think of being as simple (or better) as the above.

What is the difference between dim and set in vba

According to VBA help on SET statement it sets a reference to an if you change a property the actual object will also changes.

Dim newObj as Object
Set var1=Object1(same type as Object)
Set var2=Object1(same type as Object)
Set var3=Object1(same type as Object)
Set var4=Object1(same type as Object)

the other Vars properties also changes,so:


actualy all vars are the same!

Error: 10 $digest() iterations reached. Aborting! with dynamic sortby predicate

This happened to me right after upgrading Firefox to version 51. After clearing the cache, the problem has gone.

UITableView with fixed section headers

The headers only remain fixed when the UITableViewStyle property of the table is set to UITableViewStylePlain. If you have it set to UITableViewStyleGrouped, the headers will scroll up with the cells.

Why can't I change my input value in React even with the onChange listener

In react, state will not change until you do it by using this.setState({});. That is why your console message showing old values.

MS-access reports - The search key was not found in any record - on save

You do not mention the version of Access that you are using. Microsoft reports a bug in 2000:

BUG: You receive a "The search key was not found in any record" error message when you compact a database or save design changes in Access 2000

If this is not your problem, here is a pretty comprehensive FAQ by Tony Toews, Microsoft Access MVP:

Corrupt Microsoft Access MDBs FAQ

If the problem is constantly occuring, you need to find the reason for the corruption of your table, and you will find a number of suggestions for tracking the cause in the site link above.

jquery UI dialog: how to initialize without a title bar?

This is How it can be done.

Go to themes folder--> base--> open jquery.ui.dialog.css



if you don't want to display titleBar then simply set display:none as i did in the following.

.ui dialog.ui-dialog .ui-dialog-titlebar 
    padding: .4em 1em;
    position: relative;

Samilarly for title as well.

.ui-dialog .ui-dialog-title {
    float: left;
    margin: .1em 0;
    white-space: nowrap;
    width: 90%;
    overflow: hidden;
    text-overflow: ellipsis;

Now comes close button you can also set it none or you can set its

.ui-dialog .ui-dialog-titlebar-close {
    position: absolute;
    right: .3em;
    top: 50%;
    width: 21px;
    margin: -10px 0 0 0;
    padding: 1px;
    height: 20px;



I did lots of search but nothing then i got this idea in my mind. However this will effect entire application to don't have close button,title bar for dialog but you can overcome this as well by using jquery and adding and setting css via jquery

here is syntax for this


How do I convert array of Objects into one Object in JavaScript?

Update: The world kept turning. Use a functional approach instead.

Here you go:

var arr = [{ key: "11", value: "1100" }, { key: "22", value: "2200" }];
var result = {};
for (var i=0, len=arr.length; i < len; i++) {
    result[arr[i].key] = arr[i].value;
console.log(result); // {11: "1000", 22: "2200"}

Download old version of package with NuGet

Another option is to change the version number in the packages.config file. This will cause NuGet to download the dlls for that version the next time you build.

How to select label for="XYZ" in CSS?

If the label immediately follows a specified input element:

input#example + label { ... }
input:checked + label { ... }

Exclude Blank and NA in R

Don't know exactly what kind of dataset you have, so I provide general answer.

x <- c(1,2,NA,3,4,5)
y <- c(1,2,3,NA,6,8) <- data.frame(x, y)
   x  y
1  1  1
2  2  2
3 NA  3
4  3 NA
5  4  6
6  5  8
# Exclude rows with NA values[complete.cases(,]
  x y
1 1 1
2 2 2
5 4 6
6 5 8

Angular2 set value for formGroup

I have implemented a temporary solution until angular2 support form updateValue

 initFormGroup(form: FormGroup, data: any) {
        for(var key in form.controls) {
          if(form.controls[key] instanceof FormControl) {
              let control = <FormControl>form.controls[key];
          } else if(form.controls[key] instanceof FormGroup) {
          } else if(form.controls[key] instanceof FormArray) {
            var control = <FormArray>form.controls[key];
            this.initFormArray(control, data[key]);
      initFormArray(array: FormArray, data: Array<any>){
      var clone = array.controls[0];
      for(var idx in data) {
        if(clone instanceof FormGroup)
          this.initFormGroup(<FormGroup>array.controls[idx], data[idx]);
        else if(clone instanceof FormControl)
          this.initFormControl(<FormControl>array.controls[idx], data[idx]);
        else if(clone instanceof FormArray)
          this.initFormArray(<FormArray>array.controls[idx], data[idx]);

initFormControl(control: FormControl, value:any){


this.initFormGroup(this.form, {b:"data",c:"data",d:"data",e:["data1","data2"],f:data});

note: form and data must have the same structure and i have used lodash for deepcloning jQuery and other libs can do as well

TCPDF ERROR: Some data has already been output, can't send PDF file

Add the function ob_end_clean(); before call the Output function. It worked for me within a custom Wordpress function!

$pdf->Output($pdf_name, 'I');

How can I run code on a background thread on Android?

Today I was looking for this and Mr Brandon Rude gave an excellent answer. Unfortunately, AsyncTask is now depricated, you can still use it, but it gives you a warning which is very annoying. So an alternative is to use Executors like this way (in kotlin):

    val someRunnable = object : Runnable{
      override fun run() {
        // todo: do your background tasks
          // update views / ui if you are in a fragment
        runOnUiThread {
          // update ui if you are in an activity
        * */

And in java it looks like this:

        Runnable someRunnable = new Runnable() {
            public void run() {
                // todo: background tasks
                runOnUiThread(new Runnable() {
                    public void run() {
                        // todo: update your ui / view in activity

                requireActivity().runOnUiThread(new Runnable() {
                    public void run() {
                        // todo: update your ui / view in Fragment


javascript cell number validation

<script type="text/javascript">
    function MobileNoValidation()
       var phno=/^\d{10}$/
        alert("Mobile No Should Not Be Empty");
       else if(!textMobileNo.value.match(phno))
        alert("Mobile no must be ten digit");
        alert("valid Mobile No");

Android emulator not able to access the internet

Change the DNS address of your network to (Google's DNS) or another of your preference:

  • Open "System Preferences"
  • Click on "Network"
  • Select the network which your computer is connected and click on "Advanced"
  • Select "DNS", Select the "+" button, type "" (Google's DNS) or if you prefer OpenDNS, ""
  • Select "Ok" and "Apply"

Windows & Linux:

After that close the emulator and start it again.

Error Code 1292 - Truncated incorrect DOUBLE value - Mysql

I corrected this error as there was a syntax error or some unwanted characters in the query, but MySQL was not able to catch it. I was using and in between multiple fields during update, e.g.

update user 
set token='lamblala', 
    accessverion='dummy' and 
where user = 'myself'

The problem in above query can be resolved by replacing and with comma(,)

How do I make entire div a link?

Wrapping a <a> around won't work (unless you set the <div> to display:inline-block; or display:block; to the <a>) because the div is s a block-level element and the <a> is not.

<a href="" style="display:block;">

<a href="">
   <div style="display:inline-block;">

<a href="">
   </span >

<a href="">

But maybe you should skip the <div> and choose a <span> instead, or just the plain <a>. And if you really want to make the div clickable, you could attach a javascript redirect with a onclick handler, somethign like:

document.getElementById("myId").setAttribute('onclick', 'location.href = "url"'); 

but I would recommend against that.

Export P7b file with all the certificate chain into CER file

If you add -chain to your command line, it will export any chained certificates.

.NET 4.0 has a new GAC, why?

I also wanted to know why 2 GAC and found the following explanation by Mark Miller in the comments section of .NET 4.0 has 2 Global Assembly Cache (GAC):

Mark Miller said... June 28, 2010 12:13 PM

Thanks for the post. "Interference issues" was intentionally vague. At the time of writing, the issues were still being investigated, but it was clear there were several broken scenarios.

For instance, some applications use Assemby.LoadWithPartialName to load the highest version of an assembly. If the highest version was compiled with v4, then a v2 (3.0 or 3.5) app could not load it, and the app would crash, even if there were a version that would have worked. Originally, we partitioned the GAC under it's original location, but that caused some problems with windows upgrade scenarios. Both of these involved code that had already shipped, so we moved our (version-partitioned GAC to another place.

This shouldn't have any impact to most applications, and doesn't add any maintenance burden. Both locations should only be accessed or modified using the native GAC APIs, which deal with the partitioning as expected. The places where this does surface are through APIs that expose the paths of the GAC such as GetCachePath, or examining the path of mscorlib loaded into managed code.

It's worth noting that we modified GAC locations when we released v2 as well when we introduced architecture as part of the assembly identity. Those added GAC_MSIL, GAC_32, and GAC_64, although all still under %windir%\assembly. Unfortunately, that wasn't an option for this release.

Hope it helps future readers.

How to retry after exception?

If you want a solution without nested loops and invoking break on success you could developer a quick wrap retriable for any iterable. Here's an example of a networking issue that I run into often - saved authentication expires. The use of it would read like this:

client = get_client()
smart_loop = retriable(list_of_values):

for value in smart_loop:
    except ClientAuthExpired:
        client = get_client()
    except NetworkTimeout:

Subtract minute from DateTime in SQL Server 2005

SELECT DATEADD(minute, -15, '2000-01-01 08:30:00'); 

The second value (-15 in this case) must be numeric (i.e. not a string like '00:15'). If you need to subtract hours and minutes I would recommend splitting the string on the : to get the hours and minutes and subtracting using something like

SELECT DATEADD(minute, -60 * @h - @m, '2000-01-01 08:30:00'); 

where @h is the hour part of your string and @m is the minute part of your string


Here is a better way:

SELECT CAST('2000-01-01 08:30:00' as datetime) - CAST('00:15' AS datetime)

returning a Void object

There is no generic type which will tell the compiler that a method returns nothing.

I believe the convention is to use Object when inheriting as a type parameter


Propagate the type parameter up and then let users of your class instantiate using Object and assigning the object to a variable typed using a type-wildcard ?:

interface B<E>{ E method(); }

class A<T> implements B<T>{

    public T method(){
        // do something
        return null;

A<?> a = new A<Object>();

What are all the possible values for HTTP "Content-Type" header?

As is defined in RFC 1341:

In the Extended BNF notation of RFC 822, a Content-Type header field value is defined as follows:

Content-Type := type "/" subtype *[";" parameter]

type := "application" / "audio" / "image" / "message" / "multipart" / "text" / "video" / x-token

x-token := < The two characters "X-" followed, with no intervening white space, by any token >

subtype := token

parameter := attribute "=" value

attribute := token

value := token / quoted-string

token := 1*

tspecials := "(" / ")" / "<" / ">" / "@" ; Must be in / "," / ";" / ":" / "\" / <"> ; quoted-string, / "/" / "[" / "]" / "?" / "." ; to use within / "=" ; parameter values

And a list of known MIME types that can follow it (or, as Joe remarks, the IANA source).

As you can see the list is way too big for you to validate against all of them. What you can do is validate against the general format and the type attribute to make sure that is correct (the set of options is small) and just assume that what follows it is correct (and of course catch any exceptions you might encounter when you put it to actual use).

Also note the comment above:

If another primary type is to be used for any reason, it must be given a name starting with "X-" to indicate its non-standard status and to avoid any potential conflict with a future official name.

You'll notice that a lot of HTTP requests/responses include an X- header of some sort which are self defined, keep this in mind when validating the types.

Error: JAVA_HOME is not defined correctly executing maven

Use these two commands (for Java 8):

sudo update-java-alternatives --set java-8-oracle
java -XshowSettings 2>&1 | grep -e 'java.home' | awk '{print "JAVA_HOME="$3}' | sed "s/\/jre//g" >> /etc/environment

How to add meta tag in JavaScript


document.head.innerHTML += '<meta http-equiv="X-UA-..." content="IE=edge">'

Predefined type 'System.ValueTuple´2´ is not defined or imported

I also came accross this issue as I upgraded from .NET 4.6.2 to .NET 4.7.2. Unfortunately, I was not able to remove the package reference to System.ValueTuple because another NuGet package I use depends on it.

Finally I was able to locate the root cause: There was a .NET 4.6.2 version of mscorlib.dll lying around in the project folder (output of a publish operation) and MSBuild decided to reference this assembly instead of the official .NET 4.7.2 reference assembly located in C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.7.2.

Due to the fact that System.ValueTuple was introduced in .NET 4.7, MSBuild failed the compilation because it could not find the type in the reference assembly of .NET 4.6.2.

(duplicate of

Handling Enter Key in Vue.js

In vue 2, You can catch enter event with v-on:keyup.enter check the documentation:

I leave a very simple example:

var vm = new Vue({_x000D_
  el: '#app',_x000D_
  data: {msg: ''},_x000D_
  methods: {_x000D_
    onEnter: function() {_x000D_
       this.msg = 'on enter event';_x000D_
<script src=""></script>_x000D_
<div id="app">_x000D_
  <input v-on:keyup.enter="onEnter" />_x000D_
  <h1>{{ msg }}</h1>_x000D_

Good luck

Changing three.js background to transparent or other color

I came across this when I started using three.js as well. It's actually a javascript issue. You currently have:

renderer.setClearColorHex( 0x000000, 1 );

in your threejs init function. Change it to:

renderer.setClearColorHex( 0xffffff, 1 );

Update: Thanks to HdN8 for the updated solution:

renderer.setClearColor( 0xffffff, 0);

Update #2: As pointed out by WestLangley in another, similar question - you must now use the below code when creating a new WebGLRenderer instance in conjunction with the setClearColor() function:

var renderer = new THREE.WebGLRenderer({ alpha: true });

Update #3: Mr.doob points out that since r78 you can alternatively use the code below to set your scene's background colour:

var scene = new THREE.Scene(); // initialising the scene
scene.background = new THREE.Color( 0xff0000 );

momentJS date string add 5 days

You can reduce what they said in a few lines of code:

var nowPlusOneDay = moment().add('days', 1);
var nowPlusOneDayStr = nowPlusOneDay.format('YYYY-MM-DD');

alert('nowPlusOneDay Without Format(Unix Date):'+nowPlusOneDay);
alert('nowPlusOneDay Formatted(String):'+nowPlusOneDayStr);

How to get the parents of a Python class?

New-style classes have an mro method you can call which returns a list of parent classes in method resolution order.

How to put an image next to each other

try putting both images next to each other. Like this:

    <div id="icons"><a href=""><img src="images/facebook.png"></a><a href=""><img src="images/twitter.png"></a>

Android Use Done button on Keyboard to click button

Try this for Xamarin.Android (Cross Platform)

edittext.EditorAction += (object sender, TextView.EditorActionEventArgs e) {
       if (e.ActionId.Equals (global::Android.Views.InputMethods.ImeAction.Done)) {
           //TODO Something

How to get evaluated attributes inside a custom directive

The other answers here are very much correct, and valuable. But sometimes you just want simple: to get a plain old parsed value at directive instantiation, without needing updates, and without messing with isolate scope. For instance, it can be handy to provide a declarative payload into your directive as an array or hash-object in the form:

my-directive-name="['string1', 'string2']"

In that case, you can cut to the chase and just use a nice basic angular.$eval(attr.attrName).

element.val("value = "+angular.$eval(attr.value));

Working Fiddle.

Can I convert a boolean to Yes/No in a ASP.NET GridView

I use this code for VB:

<asp:TemplateField HeaderText="Active" SortExpression="Active">
    <ItemTemplate><%#IIf(Boolean.Parse(Eval("Active").ToString()), "Yes", "No")%></ItemTemplate>

And this should work for C# (untested):

<asp:TemplateField HeaderText="Active" SortExpression="Active">
    <ItemTemplate><%# (Boolean.Parse(Eval("Active").ToString())) ? "Yes" : "No" %></ItemTemplate>

Toggle visibility property of div

To clean this up a little bit and maintain a single line of code (like you would with a toggle()), you can use a ternary operator so your code winds up looking like this (also using jQuery):

$('#video-over').css('visibility', $('#video-over').css('visibility') == 'hidden' ? 'visible' : 'hidden');

How to determine an object's class?

Multiple right answers were presented, but there are still more methods: Class.isAssignableFrom() and simply attempting to cast the object (which might throw a ClassCastException).

Possible ways summarized

Let's summarize the possible ways to test if an object obj is an instance of type C:

// Method #1
if (obj instanceof C)

// Method #2
if (C.class.isInstance(obj))

// Method #3
if (C.class.isAssignableFrom(obj.getClass()))

// Method #4
try {
    C c = (C) obj;
    // No exception: obj is of type C or IT MIGHT BE NULL!
} catch (ClassCastException e) {

// Method #5
try {
    C c = C.class.cast(obj);
    // No exception: obj is of type C or IT MIGHT BE NULL!
} catch (ClassCastException e) {

Differences in null handling

There is a difference in null handling though:

  • In the first 2 methods expressions evaluate to false if obj is null (null is not instance of anything).
  • The 3rd method would throw a NullPointerException obviously.
  • The 4th and 5th methods on the contrary accept null because null can be cast to any type!

To remember: null is not an instance of any type but it can be cast to any type.


  • Class.getName() should not be used to perform an "is-instance-of" test becase if the object is not of type C but a subclass of it, it may have a completely different name and package (therefore class names will obviously not match) but it is still of type C.
  • For the same inheritance reason Class.isAssignableFrom() is not symmetric:
    obj.getClass().isAssignableFrom(C.class) would return false if the type of obj is a subclass of C.

Convert a Python int into a big-endian string of bytes

Using the bitstring module:

>>> bitstring.BitArray(uint=1245427, length=24).bytes

Note though that for this method you need to specify the length in bits of the bitstring you are creating.

Internally this is pretty much the same as Alex's answer, but the module has a lot of extra functionality available if you want to do more with your data.

python mpl_toolkits installation issue

It is not on PyPI and you should not be installing it via pip. If you have matplotlib installed, you should be able to import mpl_toolkits directly:

$ pip install --upgrade matplotlib

$ python
>>> import mpl_toolkits

Can't find out where does a node.js app running and can't kill it

If all those kill process commands don't work for you, my suggestion is to check if you were using any other packages to run your node process.

I had the similar issue, and it was due to I was running my node process using PM2(a NPM package). The kill [processID] command disables the process but keeps the port occupied. Hence I had to go into PM2 and dump all node process to free up the port again.

Google Maps how to Show city or an Area outline

use this code:

<iframe width="600" height="450" frameborder="0" style="border:0" src="" allowfullscreen></iframe>

What is the garbage collector in Java?

An object becomes eligible for Garbage collection or GC if it's not reachable from any live threads or by any static references.

In other words, you can say that an object becomes eligible for garbage collection if its all references are null. Cyclic dependencies are not counted as the reference so if object A has a reference to object B and object B has a reference to Object A and they don't have any other live reference then both Objects A and B will be eligible for Garbage collection.

Heap Generations for Garbage Collection -

Java objects are created in Heap and Heap is divided into three parts or generations for the sake of garbage collection in Java, these are called as Young(New) generation, Tenured(Old) Generation and Perm Area of the heap.

Java Heap Space New Generation is further divided into three parts known as Eden space, Survivor 1 and Survivor 2 space. When an object first created in heap its gets created in new generation inside Eden space and after subsequent minor garbage collection if an object survives its gets moved to survivor 1 and then survivor 2 before major garbage collection moved that object to old or tenured generation.

Perm space of Java Heap is where JVM stores Metadata about classes and methods, String pool and Class level details.

Heap Generations for Garbage Collection

Refer here for more : Garbage Collection

You can't force JVM to run Garbage Collection though you can make a request using System.gc() or Runtime.gc() method.

In java.lang.System

public static void gc() {

In java.lang.Runtime

public native void gc();  // note native  method

Mark and Sweep Algorithm -

This is one of the most popular algorithms used by Garbage collection. Any garbage collection algorithm must perform 2 basic operations. One, it should be able to detect all the unreachable objects and secondly, it must reclaim the heap space used by the garbage objects and make the space available again to the program.

The above operations are performed by Mark and Sweep Algorithm in two phases:

  1. Mark phase
  2. Sweep phase

read here for more details - Mark and Sweep Algorithm

Flask Error: "Method Not Allowed The method is not allowed for the requested URL"

What is happening here is that database route does not accept any url methods.

I would try putting the url methods in the app route just like you have in the entry_page function:

@app.route('/entry', methods=['GET', 'POST'])
def entry_page():
    if request.method == 'POST':
        date = request.form['date']
        title = request.form['blog_title']
        post = request.form['blog_main']
        post_entry = models.BlogPost(date = date, title = title, post = post)
        return redirect(url_for('database'))
        return render_template('entry.html')

@app.route('/database', methods=['GET', 'POST'])        
def database():
    query = []
    for i in session.query(models.BlogPost):
    return render_template('database.html', query = query)

Disable Scrolling on Body

This post was helpful, but just wanted to share a slight alternative that may help others:

Setting max-height instead of height also does the trick. In my case, I'm disabling scrolling based on a class toggle. Setting .someContainer {height: 100%; overflow: hidden;} when the container's height is smaller than that of the viewport would stretch the container, which wouldn't be what you'd want. Setting max-height accounts for this, but if the container's height is greater than the viewport's when the content changes, still disables scrolling.

How do I parse a YAML file in Ruby?

I had the same problem but also wanted to get the content of the file (after the YAML front-matter).

This is the best solution I have found:

if (md = contents.match(/^(?<metadata>---\s*\n.*?\n?)^(---\s*$\n?)/m))
  self.contents = md.post_match
  self.metadata = YAML.load(md[:metadata])

Source and discussion:

How can I scale an entire web page with CSS?

For Cross-Browser Compatibility :

Example Goes Below :

<html><body class="entire-webpage"></body></html>

        zoom: 2;
        -moz-transform: scale(2);/* Firefox Property */
        -moz-transform-origin: 0 0;
        -o-transform: scale(2);/* Opera Property */
        -o-transform-origin: 0 0;
        -webkit-transform: scale(2);/* Safari Property */
        -webkit-transform-origin: 0 0;
        transform: scale(2); /* Standard Property */
        transform-origin: 0 0;  /* Standard Property */

OpenMP set_num_threads() is not working

The omp_get_num_threads() function returns the number of threads that are currently in the team executing the parallel region from which it is called. You are calling it outside of the parallel region, which is why it returns 1.

bower command not found

Alternatively, you can use npx which comes along with the npm > 5.6.

npx bower install

How to write file in UTF-8 format?

I put all together and got easy way to convert ANSI text files to "UTF-8 No Mark":

function filesToUTF8($searchdir,$convdir,$filetypes) {
  $get_files = glob($searchdir.'*{'.$filetypes.'}', GLOB_BRACE);
  foreach($get_files as $file) {
    $expl_path = explode('/',$file);
    $filename = end($expl_path);
    $get_file_content = file_get_contents($file);
    $new_file_content = iconv(mb_detect_encoding($get_file_content, mb_detect_order(), true), "UTF-8", $get_file_content);
    $put_new_file = file_put_contents($convdir.$filename,$new_file_content);

Usage: filesToUTF8('C:/Temp/','C:/Temp/conv_files/','php,txt');

How to check if Receiver is registered in Android?

For me the following worked:

if (receiver.isOrderedBroadcast()) {

What does [object Object] mean? (JavaScript)

That is because there are different types of objects in Javascript!

For example

  • Function objects:

stringify(function (){}) -> [object Function]

  • Array objects:

stringify([]) -> [object Array]

  • RegExp objects

stringify(/x/) -> [object RegExp]

  • Date objects

stringify(new Date) -> [object Date]

  • Object objects!

stringify({}) -> [object Object]

the constructor function is called Object (with a capital "O"), and the term "object" (with small "o") refers to the structural nature of the thingy.

When you're talking about "objects" in Javascript, you actually mean "Object objects", and not the other types.

If you want to see value inside "[Object objects]" use:


The program can't start because libgcc_s_dw2-1.dll is missing

Find that dll on your PC, and copy it into the same directory your executable is in.

Static extension methods

specifically I want to overload Boolean.Parse to allow an int argument.

Would an extension for int work?

public static bool ToBoolean(this int source){
    // do it
    // return it

Then you can call it like this:

int x = 1;

bool y = x.ToBoolean();

What is causing ImportError: No module named pkg_resources after upgrade of Python on os X?

I encountered with the same problem when i am working on autobahn related project.

1) So I download the setuptools.-0.9.8.tar.gz form and extract it.

2 )Then i get the pkg_resources module and copy it to the folder where it needed. **in my case that folder was C:\Python27\Lib\site-packages\autobahn

Iterating through populated rows

For the benefit of anyone searching for similar, see worksheet .UsedRange,
e.g. ? ActiveSheet.UsedRange.Rows.Count
and loops such as
For Each loopRow in Sheets(1).UsedRange.Rows: Print loopRow.Row: Next

Communication between tabs or windows

Checkout AcrossTabs - Easy communication between cross-origin browser tabs. It uses a combination of postMessage and sessionStorage API to make communication much easier and reliable.

There are different approaches and each one has its own advantages and disadvantages. Lets discuss each:

  1. LocalStorage


    1. Web storage can be viewed simplistically as an improvement on cookies, providing much greater storage capacity. If you look at the Mozilla source code we can see that 5120KB (5MB which equals 2.5 Million chars on Chrome) is the default storage size for an entire domain. This gives you considerably more space to work with than a typical 4KB cookie.
    2. The data is not sent back to the server for every HTTP request (HTML, images, JavaScript, CSS, etc) - reducing the amount of traffic between client and server.
    3. The data stored in localStorage persists until explicitly deleted. Changes made are saved and available for all current and future visits to the site.


    1. It works on same-origin policy. So, data stored will only be able available on the same origin.
  2. Cookies


    1. Compared to others, there's nothing AFAIK.


    1. The 4K limit is for the entire cookie, including name, value, expiry date etc. To support most browsers, keep the name under 4000 bytes, and the overall cookie size under 4093 bytes.
    2. The data is sent back to the server for every HTTP request (HTML, images, JavaScript, CSS, etc) - increasing the amount of traffic between client and server.

      Typically, the following are allowed:

      • 300 cookies in total
      • 4096 bytes per cookie
      • 20 cookies per domain
      • 81920 bytes per domain(Given 20 cookies of max size 4096 = 81920 bytes.)
  3. sessionStorage


    1. It is similar to localStorage.
    2. Changes are only available per window (or tab in browsers like Chrome and Firefox). Changes made are saved and available for the current page, as well as future visits to the site on the same window. Once the window is closed, the storage is deleted


    1. The data is available only inside the window/tab in which it was set.
    2. The data is not persistent i.e. it will be lost once the window/tab is closed.
    3. Like localStorage, tt works on same-origin policy. So, data stored will only be able available on the same origin.
  4. PostMessage


    1. Safely enables cross-origin communication.
    2. As a data point, the WebKit implementation (used by Safari and Chrome) doesn't currently enforce any limits (other than those imposed by running out of memory).


    1. Need to open a window from the current window and then can communicate only as long as you keep the windows open.
    2. Security concerns - Sending strings via postMessage is that you will pick up other postMessage events published by other JavaScript plugins, so be sure to implement a targetOrigin and a sanity check for the data being passed on to the messages listener.
  5. A combination of PostMessage + SessionStorage

    Using postMessage to communicate between multiple tabs and at the same time using sessionStorage in all the newly opened tabs/windows to persist data being passed. Data will be persisted as long as the tabs/windows remain opened. So, even if the opener tab/window gets closed, the opened tabs/windows will have the entire data even after getting refreshed.

I have written a JavaScript library for this, named AcrossTabs which uses postMessage API to communicate between cross-origin tabs/windows and sessionStorage to persist the opened tabs/windows identity as long as they live.

How to find/identify large commits in git history?

How can I track down the large files in the git history?

Start by analyzing, validating and selecting the root cause. Use git-repo-analysis to help.

You may also find some value in the detailed reports generated by BFG Repo-Cleaner, which can be run very quickly by cloning to a Digital Ocean droplet using their 10MiB/s network throughput.

Change Name of Import in Java, or import two classes with the same name

As the other answers already stated, Java does not provide this feature.

Implementation of this feature has been requested multiple times, e.g. as JDK-4194542: class name aliasing or JDK-4214789: Extend import to allow renaming of imported type.

From the comments:

This is not an unreasonable request, though hardly essential. The occasional use of fully qualified names is not an undue burden (unless the library really reuses the same simple names right and left, which is bad style).

In any event, it doesn't pass the bar of price/performance for a language change.

So I guess we will not see this feature in Java anytime soon :-P

How to center a WPF app on screen?

Put this in your window constructor

WindowStartupLocation = System.Windows.WindowStartupLocation.CenterScreen;

.NET FrameworkSupported in: 4, 3.5, 3.0

.NET Framework Client ProfileSupported in: 4, 3.5 SP1

python pandas remove duplicate columns

If I'm not mistaken, the following does what was asked without the memory problems of the transpose solution and with fewer lines than @kalu 's function, keeping the first of any similarly named columns.

Cols = list(df.columns)
for i,item in enumerate(df.columns):
    if item in df.columns[:i]: Cols[i] = "toDROP"
df.columns = Cols
df = df.drop("toDROP",1)

How do I set the default locale in the JVM?

You can use JVM args

java -Duser.language=es -Duser.variant=Traditional_WIN

Execute function after Ajax call is complete

You can use .ajaxStop() or .ajaxComplete()

.ajaxComplete() fires after completion of each AJAX request on your page.

$( document ).ajaxComplete(function() {

.ajaxStop() fires after completion of all AJAX requests on your page.

$( document ).ajaxStop(function() {

how to compare two string dates in javascript?

Directly parsing a date string that is not in yyyy-mm-dd format, like in the accepted answer does not work. The answer by vitran does work but has some JQuery mixed in so I reworked it a bit.

// Takes two strings as input, format is dd/mm/yyyy
// returns true if d1 is smaller than or equal to d2

function compareDates(d1, d2){
var parts =d1.split('/');
var d1 = Number(parts[2] + parts[1] + parts[0]);
parts = d2.split('/');
var d2 = Number(parts[2] + parts[1] + parts[0]);
return d1 <= d2;

P.S. would have commented directly to vitran's post but I don't have the rep to do that.

How to delete an SVN project from SVN repository

The correct sentence is: svnadmin deltify $PATH. do not forghet to delet the project or repository from the file svn-acl (if you use it). if you simply delete the folder of repository you may corrupt the svn directory depending on how your svn is configured in your environment.

How do I generate random number for each row in a TSQL Select?

If you want to generate a random number between 1 and 14 inclusive.

SELECT CONVERT(int, RAND() * (14 - 1) + 1)


SELECT ABS(CHECKSUM(NewId())) % (14 -1) + 1

Number of visitors on a specific page

As Blexy already answered, go to "Behavior > Site Content > All Pages".

Just pay attention that "Behavior" appears two times in the left sidebar and we need to click on the second option:


Pass user defined environment variable to tomcat

If you are starting your Tomcat from Eclipse ("Servers" view) then you should have a "Run/Run Configuration" (menu) entry called "Apache Tomcat / Tomcat …". When you select this entry in the list of run configurations you get a window with several tabs, one of which is labeled "Environment". There you can configure environment variables for your Tomcat. Be sure to restart Tomcat afterwards.

Angular 4 default radio button checked by default

getting following error

It happens:  Error: 
      ngModel cannot be used to register form controls with a parent formGroup directive.  Try using
      formGroup's partner directive "formControlName" instead.  Example:

Getting data-* attribute for onclick event for an html element

User $() to get jQuery object from your link and data() to get your values

<a id="option1" 
       Click to do something

How do you echo a 4-digit Unicode character in Bash?

If you don't mind a Perl one-liner:

$ perl -CS -E 'say "\x{2620}"'

-CS enables UTF-8 decoding on input and UTF-8 encoding on output. -E evaluates the next argument as Perl, with modern features like say enabled. If you don't want a newline at the end, use print instead of say.

How to import data from one sheet to another


You can do it with a simple VLOOKUP formula. I've put the data in the same sheet, but you can also reference a different worksheet. For the price column just change the last value from 2 to 3, as you are referencing the third column of the matrix "A2:C4". VLOOKUP example

External Reference

To reference a cell of the same Workbook use the following pattern:




To reference a cell of a different Workbook use this pattern:




What is the "__v" field in Mongoose

It is the version key.It gets updated whenever a new update is made. I personally don't like to disable it .

Read this solution if you want to know more [1]: Mongoose versioning: when is it safe to disable it?

div hover background-color change?

if you want the color to change when you have simply add the :hover pseudo

div.e:hover {

Java - sending HTTP parameters via POST method easily

Try this pattern:

public static PricesResponse getResponse(EventRequestRaw request) {

    // String urlParameters  = "param1=a&param2=b&param3=c";
    String urlParameters = Piping.serialize(request);

    HttpURLConnection conn = RestClient.getPOSTConnection(endPoint, urlParameters);

    PricesResponse response = null;

    try {
        // POST
        OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());

        // RESPONSE
        BufferedReader reader = new BufferedReader(new InputStreamReader((conn.getInputStream()), StandardCharsets.UTF_8));
        String json = Buffering.getString(reader);
        response = (PricesResponse) Piping.deserialize(json, PricesResponse.class);


    } catch (Exception e) {


    System.out.println("PricesClient: " + response.toString());

    return response;

public static HttpURLConnection getPOSTConnection(String endPoint, String urlParameters) {

    return RestClient.getConnection(endPoint, "POST", urlParameters);


public static HttpURLConnection getConnection(String endPoint, String method, String urlParameters) {

    System.out.println("ENDPOINT " + endPoint + " METHOD " + method);
    HttpURLConnection conn = null;

    try {
        URL url = new URL(endPoint);
        conn = (HttpURLConnection) url.openConnection();
        conn.setRequestProperty("Content-Type", "text/plain");

    } catch (IOException e) {

    return conn;

chai test array equality doesn't work as expected

You can use .deepEqual()

const { assert } = require('chai');

assert.deepEqual([0,0], [0,0]);

Convert data.frame column format from character to factor

You could use dplyr::mutate_if() to convert all character columns or dplyr::mutate_at() for select named character columns to factors:


# all character columns to factor:
df <- mutate_if(df, is.character, as.factor)

# select character columns 'char1', 'char2', etc. to factor:
df <- mutate_at(df, vars(char1, char2), as.factor)

How can I know if Object is String type object?

javamonkey79 is right. But don't forget what you might want to do (e.g. try something else or notify someone) if object is not an instance of String.

String myString;
if (object instanceof String) {
  myString = (String) object;
} else {
  // do something else     

BTW: If you use ClassCastException instead of Exception in your code above, you can be sure that you will catch the exception caused by casting object to String. And not any other exceptions caused by other code (e.g. NullPointerExceptions).

Temporarily switch working copy to a specific Git commit

If you are at a certain branch mybranch, just go ahead and git checkout commit_hash. Then you can return to your branch by git checkout mybranch. I had the same game bisecting a bug today :) Also, you should know about git bisect.

How do I get the name of the active user via the command line in OS X?

You can also retrieve it from the environment variables, but that is probably not secure, so I would go with Andrew's answer.

printenv USER

If you need to retrieve it from an app, like Node, it's easier to get it from the environment variables, such as


Python: Random numbers into a list

You could use random.sample to generate the list with one call:

import random
my_randoms = random.sample(range(100), 10)

That generates numbers in the (inclusive) range from 0 to 99. If you want 1 to 100, you could use this (thanks to @martineau for pointing out my convoluted solution):

my_randoms = random.sample(range(1, 101), 10)

Detecting endianness programmatically in a C++ program

The way C compilers (at least everyone I know of) work the endianness has to be decided at compile time. Even for biendian processors (like ARM och MIPS) you have to choose endianness at compile time. Further more the endianness is defined in all common file formats for executables (such as ELF). Although it is possible to craft a binary blob of biandian code (for some ARM server exploit maybe?) it probably has to be done in assembly.

Show values from a MySQL database table inside a HTML table on a webpage

Surely a better solution would by dynamic so that it would work for any query without having to know the column names?

If so, try this (obviously the query should match your database):

// You'll need to put your db connection details in here.
$conn = new mysqli($server_hostname, $server_username, $server_password, $server_database);

// Run the query.
$result = $conn->query("SELECT * FROM table LIMIT 10");

// Get the result in to a more usable format.
$query = array();
while($query[] = mysqli_fetch_assoc($result));

// Output a dynamic table of the results with column headings.
echo '<table border="1">';
echo '<tr>';
foreach($query[0] as $key => $value) {
    echo '<td>';
    echo $key;
    echo '</td>';
echo '</tr>';
foreach($query as $row) {
    echo '<tr>';
    foreach($row as $column) {
        echo '<td>';
        echo $column;
        echo '</td>';
    echo '</tr>';
echo '</table>';

Taken from here:

Set CSS property in Javascript?

<h1>Silence and Smile</h1>
<input  type="button"  value="Show Red"   onclick="document.getElementById('h1').style.color='Red'"/>
<input  type="button"  value="Show Green" onclick="document.getElementById('h1').style.color='Green'"/>

Difference between x86, x32, and x64 architectures?

As the 64bit version is an x86 architecture and was accordingly first called x86-64, that would be the most appropriate name, IMO. Also, x32 is a thing (as mentioned before)—‘x64’, however, is not a continuation of that, so is (theoretically) missleading (even though many people will know what you are talking about) and should thus only be recognised as a marketing thing, not an ‘official’ architecture (again, IMO–obviously, others disagree).

Overlay normal curve to histogram in R

You just need to find the right multiplier, which can be easily calculated from the hist object.

myhist <- hist(mtcars$mpg)
multiplier <- myhist$counts / myhist$density
mydensity <- density(mtcars$mpg)
mydensity$y <- mydensity$y * multiplier[1]


enter image description here

A more complete version, with a normal density and lines at each standard deviation away from the mean (including the mean):

myhist <- hist(mtcars$mpg)
multiplier <- myhist$counts / myhist$density
mydensity <- density(mtcars$mpg)
mydensity$y <- mydensity$y * multiplier[1]


myx <- seq(min(mtcars$mpg), max(mtcars$mpg), length.out= 100)
mymean <- mean(mtcars$mpg)
mysd <- sd(mtcars$mpg)

normal <- dnorm(x = myx, mean = mymean, sd = mysd)
lines(myx, normal * multiplier[1], col = "blue", lwd = 2)

sd_x <- seq(mymean - 3 * mysd, mymean + 3 * mysd, by = mysd)
sd_y <- dnorm(x = sd_x, mean = mymean, sd = mysd) * multiplier[1]

segments(x0 = sd_x, y0= 0, x1 = sd_x, y1 = sd_y, col = "firebrick4", lwd = 2)

Passing a Bundle on startActivity()?

You can use the Bundle from the Intent:

Bundle extras = myIntent.getExtras();

Or an entire bundle:


Is this what you're looking for?

How to find a value in an array and remove it by using PHP array functions?

The unset array_search has some pretty terrible side effects because it can accidentally strip the first element off your array regardless of the value:

        // bad side effects
        $a = [0,1,2,3,4,5];
        unset($a[array_search(3, $a)]);
        unset($a[array_search(6, $a)]);
        // result: [1,2,4,5]
        // what? where is 0?
        // it was removed because false is interpreted as 0

        // goodness
        $b = [0,1,2,3,4,5];
        $b = array_diff($b, [3,6]);
        // result: [0,1,2,4,5]

If you know that the value is guaranteed to be in the array, go for it, but I think the array_diff is far safer. (I'm using php7)

find_spec_for_exe': can't find gem bundler (>= 0.a) (Gem::GemNotFoundException)

The problem in my case is that the Gemfile.lock file had a BUNDLED_WITH version of 1.16.1 and gem install bundler installed version 2.0.1, so there was a version mismatch when looking to right the folder

gem install bundler -v 1.16.1 fixed it

Of course, you can also change your Gemfile.lock's BUNDLED_WITH with last bundler version and use recent software, as Sam3000 suggests

SQL: set existing column as Primary Key in MySQL

ALTER TABLE your_table

iOS 8 UITableView separator inset 0 not working

Just override the "cellForRowAtIndexPath" and set "cell.preservesSuperviewLayoutMargins = false" and "cell.separatorInset =" and "cell.layoutMargins ="

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell: LayoutTableViewCell! = tableView.dequeueReusableCell(withIdentifier: "LayoutCell") as? LayoutTableViewCell

    let currentLayout = OrderLayouts()[indexPath.row]

    cell.NameLabel?.text =
    cell.DescrLabel?.text = currentLayout.descr


        cell.DescrLabel?.text = "\( \n \(currentLayout.descr)"


    cell.preservesSuperviewLayoutMargins = false
    cell.separatorInset =
    cell.layoutMargins =

    return cell


How do I include a JavaScript script file in Angular and call a function from that script?

You can either

import * as abc from './abc';;


import { xyz } from './abc';

Usage of __slots__?

You have — essentially — no use for __slots__.

For the time when you think you might need __slots__, you actually want to use Lightweight or Flyweight design patterns. These are cases when you no longer want to use purely Python objects. Instead, you want a Python object-like wrapper around an array, struct, or numpy array.

class Flyweight(object):

    def get(self, theData, index):
        return theData[index]

    def set(self, theData, index, value):
        theData[index]= value

The class-like wrapper has no attributes — it just provides methods that act on the underlying data. The methods can be reduced to class methods. Indeed, it could be reduced to just functions operating on the underlying array of data.

How to check if a JavaScript variable is NOT undefined?

var lastname = "Hi";

if(typeof lastname !== "undefined")
  alert("Hi. Variable is defined.");

How to get an object's methods?

In Chrome is keys(foo.prototype). Returns ["a", "b"].

See: image description here

Later edit: If you need to copy it quick (for bigger objects), do copy(keys(foo.prototype)) and you will have it in the clipboard.