Programs & Examples On #Lambdaj

LambdaJ is a library to manipulate a collections without any iterations.

DTO pattern: Best way to copy properties between two objects

I suggest you should use one of the mappers' libraries: Mapstruct, ModelMapper, etc. With Mapstruct your mapper will look like:

@Mapper
public interface UserMapper {     
    UserMapper INSTANCE = Mappers.getMapper( UserMapper.class ); 

    UserDTO toDto(User user);
}

The real object with all getters and setters will be automatically generated from this interface. You can use it like:

UserDTO userDTO = UserMapper.INSTANCE.toDto(user);

You can also add some logic for your activeText filed using @AfterMapping annotation.

How do I check that multiple keys are in a dict in a single pass?

You don't have to wrap the left side in a set. You can just do this:

if {'foo', 'bar'} <= set(some_dict):
    pass

This also performs better than the all(k in d...) solution.

Several ports (8005, 8080, 8009) required by Tomcat Server at localhost are already in use

If you are on mac environment, here is what I did.

Find the process id running on this port from terminal, eg, 8080:

lsof -i :8080

and kill it:

kill -9 <PID>  

Example:

You may see following result:

MacSys:bin krunal.$ lsof -i :8080

COMMAND   PID     USER   FD   TYPE     DEVICE  SIZE/OFF   NODE  NAME
java     21347   krunal  52u  IPv6      XXX      0t0      TCP  *:http-xxx (LISTEN)

and kill it: (kill -9 21347)

How to pass all arguments passed to my bash script to a function of mine?

I needed a variation on this, which I expect will be useful to others:

function diffs() {
        diff "${@:3}" <(sort "$1") <(sort "$2")
}

The "${@:3}" part means all the members of the array starting at 3. So this function implements a sorted diff by passing the first two arguments to diff through sort and then passing all other arguments to diff, so you can call it similarly to diff:

diffs file1 file2 [other diff args, e.g. -y]

How do I declare a 2d array in C++ using new?

Start by defining the array using pointers (Line 1):

int** a = new int* [x];     //x is the number of rows
for(int i = 0; i < x; i++)
    a[i] = new int[y];     //y is the number of columns

calling java methods in javascript code

Java is a server side language, whereas javascript is a client side language. Both cannot communicate. If you have setup some server side script using Java you could use AJAX on the client in order to send an asynchronous request to it and thus invoke any possible Java functions. For example if you use jQuery as js framework you may take a look at the $.ajax() method. Or if you wanted to do it using plain javascript, here's a tutorial.

Match the path of a URL, minus the filename extension

There's no need to use a regular expression to dissect a URL. PHP has built-in functions for this, pathinfo() and parse_url().

When do you use Java's @Override annotation and why?

It does allow you (well, the compiler) to catch when you've used the wrong spelling on a method name you are overriding.

Why am I seeing net::ERR_CLEARTEXT_NOT_PERMITTED errors after upgrading to Cordova Android 8?

The default API level in the Cordova Android platform has been upgraded. On an Android 9 device, clear text communication is now disabled by default.

To allow clear text communication again, set the android:usesCleartextTraffic on your application tag to true:

<platform name="android">
  <edit-config file="app/src/main/AndroidManifest.xml" mode="merge" target="/manifest/application">
      <application android:usesCleartextTraffic="true" />
  </edit-config>
</platform>

As noted in the comments, if you have not defined the android XML namespace previously, you will receive an error: unbound prefix during build. This indicates that you need to add it to your widget tag in the same config.xml, like so:

<widget id="you-app-id" version="1.2.3"
xmlns="http://www.w3.org/ns/widgets" 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:cdv="http://cordova.apache.org/ns/1.0">

html select option separator

I'm making @Laurence Gonsalves' comment into an answer because it's the only one that works semantically and doesn't look like a hack.

Try adding this to your stylesheet:

optgroup + optgroup { border-top: 1px solid black } 

Much less cheesy looking than a bunch of dashes.

LaTeX table too wide. How to make it fit?

Use p{width} column specifier: e.g. \begin{tabular}{ l p{10cm} } will put column's content into 10cm-wide parbox, and the text will be properly broken to several lines, like in normal paragraph.

You can also use tabular* environment to specify width for the entire table.

PHP - syntax error, unexpected T_CONSTANT_ENCAPSED_STRING

'<option value=''.$key.'">'

should be

'<option value="'.$key.'">'

What is {this.props.children} and when you should use it?

I assume you're seeing this in a React component's render method, like this (edit: your edited question does indeed show that):

_x000D_
_x000D_
class Example extends React.Component {_x000D_
  render() {_x000D_
    return <div>_x000D_
      <div>Children ({this.props.children.length}):</div>_x000D_
      {this.props.children}_x000D_
    </div>;_x000D_
  }_x000D_
}_x000D_
_x000D_
class Widget extends React.Component {_x000D_
  render() {_x000D_
    return <div>_x000D_
      <div>First <code>Example</code>:</div>_x000D_
      <Example>_x000D_
        <div>1</div>_x000D_
        <div>2</div>_x000D_
        <div>3</div>_x000D_
      </Example>_x000D_
      <div>Second <code>Example</code> with different children:</div>_x000D_
      <Example>_x000D_
        <div>A</div>_x000D_
        <div>B</div>_x000D_
      </Example>_x000D_
    </div>;_x000D_
  }_x000D_
}_x000D_
_x000D_
ReactDOM.render(_x000D_
  <Widget/>,_x000D_
  document.getElementById("root")_x000D_
);
_x000D_
<div id="root"></div>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
_x000D_
_x000D_
_x000D_

children is a special property of React components which contains any child elements defined within the component, e.g. the divs inside Example above. {this.props.children} includes those children in the rendered result.

...what are the situations to use the same

You'd do it when you want to include the child elements in the rendered output directly, unchanged; and not if you didn't.

Save base64 string as PDF at client side with JavaScript

I know this question is old, but also wanted to accomplish this and came across it while looking. For internet explorer I used code from here to save a Blob. To create a blob from the base64 string there were many results on this site, so its not my code I just can't remember the specific source:

function b64toBlob(b64Data, contentType) {
    contentType = contentType || '';
    var sliceSize = 512;
    b64Data = b64Data.replace(/^[^,]+,/, '');
    b64Data = b64Data.replace(/\s/g, '');
    var byteCharacters = window.atob(b64Data);
    var byteArrays = [];

    for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
        var slice = byteCharacters.slice(offset, offset + sliceSize);

        var byteNumbers = new Array(slice.length);
        for (var i = 0; i < slice.length; i++) {
            byteNumbers[i] = slice.charCodeAt(i);
        }

        var byteArray = new Uint8Array(byteNumbers);

        byteArrays.push(byteArray);
    }

    var blob = new Blob(byteArrays, {type: contentType});
    return blob;

Using the linked filesaver:

if (window.saveAs) { window.saveAs(blob, name); }
    else { navigator.saveBlob(blob, name); }

Parse usable Street Address, City, State, Zip from a string

There is javascript port of perl Geo::StreetAddress::US package: https://github.com/hassansin/parse-address . It's regex-based and works fairly well.

Float sum with javascript

Once you read what What Every Computer Scientist Should Know About Floating-Point Arithmetic you could use the .toFixed() function:

var result = parseFloat('2.3') + parseFloat('2.4');
alert(result.toFixed(2));?

how do I get a new line, after using float:left?

Try the clear property.

Remember that float removes an element from the document layout - so yes, in a way it is "interfering" with br and p tags, in the sense that it would basically be ignoring anything in the main flow layout.

How to get the current loop index when using Iterator?

Here's a way to do it using your own variable and keeping it concise:

List<String> list = Arrays.asList("zero", "one", "two");

int i = 0;
for (Iterator<String> it = list.iterator(); it.hasNext(); i++) {
    String s = it.next();
    System.out.println(i + ": " + s);
}

Output (you guessed it):

0: zero
1: one
2: two

The advantage is that you don't increment your index within the loop (although you need to be careful to only call Iterator#next once per loop - just do it at the top).

Listing files in a specific "folder" of a AWS S3 bucket

Everything in S3 is an object. To you, it may be files and folders. But to S3, they're just objects.

Objects that end with the delimiter (/ in most cases) are usually perceived as a folder, but it's not always the case. It depends on the application. Again, in your case, you're interpretting it as a folder. S3 is not. It's just another object.

In your case above, the object users/<user-id>/contacts/<contact-id>/ exists in S3 as a distinct object, but the object users/<user-id>/ does not. That's the difference in your responses. Why they're like that, we cannot tell you, but someone made the object in one case, and didn't in the other. You don't see it in the AWS Management Console because the console is interpreting it as a folder and hiding it from you.

Since S3 just sees these things as objects, it won't "exclude" certain things for you. It's up to the client to deal with the objects as they should be dealt with.

Your Solution

Since you're the one that doesn't want the folder objects, you can exclude it yourself by checking the last character for a /. If it is, then ignore the object from the response.

Is Tomcat running?

Create a Shell script that checks if tomcat is up or down and set a cron for sh to make it check every few minutes, and auto start tomcat if down. Sample Snippet of code below

TOMCAT_PID=$(ps -ef | awk '/[t]omcat/{print $2}')
echo TOMCAT PROCESSID $TOMCAT_PID

if [ -z "$TOMCAT_PID" ]
then
    echo "TOMCAT NOT RUNNING"
    sudo /opt/tomcat/bin/startup.sh
else
   echo "TOMCAT RUNNING"
fi

Str_replace for multiple items

I guess you are looking after this:

// example
private const TEMPLATE = __DIR__.'/Resources/{type}_{language}.json';

...

public function templateFor(string $type, string $language): string
{
   return \str_replace(['{type}', '{language}'], [$type, $language], self::TEMPLATE);
}

How to use subList()

You could use streams in Java 8. To always get 10 entries at the most, you could do:

dataList.stream().skip(5).limit(10).collect(Collectors.toList());
dataList.stream().skip(30).limit(10).collect(Collectors.toList());

Error :- java runtime environment JRE or java development kit must be available in order to run eclipse

If you are using 32 bit eclipse IDE, then u might have to install the "jdk-7u45-windows-i586" version.

i have tried using 64 bit version JDK but no luck!

Thanks,

Puneeth

Pass parameters in setInterval function

Also, with IE Support > 9, you can pass more variables insider set interval that will be taken by you function. E.g:

function myFunc(arg1, arg2){};
setInterval(myFunc, 500, arg1, arg2);

Greetings!

Undefined reference to `sin`

You need to link with the math library, libm:

$ gcc -Wall foo.c -o foo -lm 

Insert new item in array on any position in PHP

Based on @Halil great answer, here is simple function how to insert new element after a specific key, while preserving integer keys:

private function arrayInsertAfterKey($array, $afterKey, $key, $value){
    $pos   = array_search($afterKey, array_keys($array));

    return array_merge(
        array_slice($array, 0, $pos, $preserve_keys = true),
        array($key=>$value),
        array_slice($array, $pos, $preserve_keys = true)
    );
} 

Avoid "current URL string parser is deprecated" warning by setting useNewUrlParser to true

You just need to set the following things before connecting to the database as below:

const mongoose = require('mongoose');

mongoose.set('useNewUrlParser', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);
mongoose.set('useUnifiedTopology', true);

mongoose.connect('mongodb://localhost/testaroo');

Also,

Replace update() with updateOne(), updateMany(), or replaceOne()
Replace remove() with deleteOne() or deleteMany().
Replace count() with countDocuments(), unless you want to count how many documents are in the whole collection (no filter).
In the latter case, use estimatedDocumentCount().

Get last key-value pair in PHP array

"SPL-way":

$splArray = SplFixedArray::fromArray($array);
$last_item_with_preserved_index[$splArray->getSize()-1] = $splArray->offsetGet($splArray->getSize()-1);

Read more about SplFixedArray and why it's in some cases ( especially with big-index sizes array-data) more preferable than basic array here => The SplFixedArray class.

Removing the textarea border in HTML

Add this to your <head>:

<style type="text/css">
    textarea { border: none; }
</style>

Or do it directly on the textarea:

<textarea style="border: none"></textarea>

Plot multiple boxplot in one graph

ggplot version of the lattice plot:

library(reshape2)
library(ggplot2)
df <- read.csv("TestData.csv", header=T)
df.m <- melt(df, id.var = "Label")

ggplot(data = df.m, aes(x=Label, y=value)) + 
         geom_boxplot() + facet_wrap(~variable,ncol = 4)

Plot: enter image description here

failed to find target with hash string android-23

Mine was complaining about 26. I looked in my folders and found a folder for 27, but not 26. So I modified my build.gradle file, replacing 26 with 27. compileSdkVersion, targetSdkVersion, and implementation (changed those numbers to v:7:27.02). That changed my error message. Then I added buildToolsVersion "27.0.3" to the android bracket section right under compileSdkVersion.

Now the make project button works with 0 messages.

Next up, how to actually select a module in my configuration so I can run this.

How do I call paint event?

In a method of your Form or Control, you have 3 choices:

this.Invalidate();  // request a delayed Repaint by the normal MessageLoop system    
this.Update();      // forces Repaint of invalidated area 
this.Refresh();     // Combines Invalidate() and Update()

Normally, you would just call Invalidate() and let the system combine that with other Screen updates. If you're in a hurry you should call Refresh() but then you run the risk that it will be repainted several times consecutively because of other controls (especially the Parent) Invalidating.

The normal way Windows (Win32 and WinForms.Net) handles this is to wait for the MessageQueue to run empty and then process all invalidated screen areas. That is efficient because when something changes that usually cascades into other things (controls) changing as well.

The most common scenario for Update() is when you change a property (say, label1.Text, which will invalidate the Label) in a for-loop and that loop is temporarily blocking the Message-Loop. Whenever you use it, you should ask yourself if you shouldn't be using a Thread instead. But the answer is't always Yes.

Check if a variable is between two numbers with Java

public static boolean between(int i, int minValueInclusive, int maxValueInclusive) {
    if (i >= minValueInclusive && i <= maxValueInclusive)
        return true;
    else
        return false;
}

https://alvinalexander.com/java/java-method-integer-is-between-a-range

Is it possible to view RabbitMQ message contents directly from the command line?

a bit late to this, but yes rabbitmq has a build in tracer that allows you to see the incomming messages in a log. When enabled, you can just tail -f /var/tmp/rabbitmq-tracing/.log (on mac) to watch the messages.

the detailed discription is here http://www.mikeobrien.net/blog/tracing-rabbitmq-messages

jQuery Refresh/Reload Page if Ajax Success after time

$.ajax("youurl", function(data){
    if (data.success == true)
    setTimeout(function(){window.location = window.location}, 5000); 
    })
)

Django 1.7 throws django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet

Another option is that you have a duplicate entry in INSTALLED_APPS. That threw this error for two different apps I tested. Apparently it's not something Django checks for, but then who's silly enough to put the same app in the list twice. Me, that's who.

Checking whether a String contains a number value in Java

Why don't you try to write a function based on Integer.parseInt(String obj) ? The function could accept as parameter your String object, and then tokenize the String and use Integer.parseInt(String obj) to extract the number from the "lucky" substring...

Javadoc of Integer.parseInt(String obj)

#1214 - The used table type doesn't support FULLTEXT indexes

Before MySQL 5.6 Full-Text Search is supported only with MyISAM Engine.

Therefore either change the engine for your table to MyISAM

CREATE TABLE gamemech_chat (
  id bigint(20) unsigned NOT NULL auto_increment,
  from_userid varchar(50) NOT NULL default '0',
  to_userid varchar(50) NOT NULL default '0',
  text text NOT NULL,
  systemtext text NOT NULL,
  timestamp datetime NOT NULL default '0000-00-00 00:00:00',
  chatroom bigint(20) NOT NULL default '0',
  PRIMARY KEY  (id),
  KEY from_userid (from_userid),
  FULLTEXT KEY from_userid_2 (from_userid),
  KEY chatroom (chatroom),
  KEY timestamp (timestamp)
) ENGINE=MyISAM;

Here is SQLFiddle demo

or upgrade to 5.6 and use InnoDB Full-Text Search.

Distinct in Linq based on only one field of the table

There are lots of discussions around this topic.

You can find one of them here:

One of the most popular suggestions have been the Distinct method taking a lambda expression as a parameter as @Servy has pointed out.

The chief architect of C#, Anders Hejlsberg has suggested the solution here. Also explaining why the framework design team decided not to add an overload of Distinct method which takes a lambda.

How to install latest version of openssl Mac OS X El Capitan

Only

export PATH=$(brew --prefix openssl)/bin:$PATH in ~/.bash_profile

has worked for me! Thank you mipadi.

Is there an easy way to strike through text in an app widget?

Add the line below:-

TextView tv=(TextView) v.findViewById(android.R.id.text1);
tv.setPaintFlags(tv.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);

use your reference instead of "tv"

What is the right way to debug in iPython notebook?

Use ipdb

Install it via

pip install ipdb

Usage:

In[1]: def fun1(a):
   def fun2(a):
       import ipdb; ipdb.set_trace() # debugging starts here
       return do_some_thing_about(b)
   return fun2(a)
In[2]: fun1(1)

For executing line by line use n and for step into a function use s and to exit from debugging prompt use c.

For complete list of available commands: https://appletree.or.kr/quick_reference_cards/Python/Python%20Debugger%20Cheatsheet.pdf

SoapFault exception: Could not connect to host

If the connection is through SSL, could be a problem of server instead of client (it is my case).

In PHP versions greater than 5.6 and 7, is important to check the CipherSuite used in server certificate. There is a full list of ciphers allowed by this versions and a full list of ciphers that do not in this web link: https://wiki.mozilla.org/Security/Server_Side_TLS#Recommended_Ciphersuite

If the cipher used is not allowed (it is a deprecated algorithm), SoapClient receives "Could not connect to host" and there is no more trace about it.

The cipher used can be checked by clients like SoapUI in the section of "SSL Info", for example.

There is no thread forum treating about this in internet.

Check this out, too: http://php.net/manual/en/migration56.openssl.php

How to set margin with jquery?

try

el.css('margin-left',mrg+'px');

using awk with column value conditions

please try this

echo $VAR | grep ClNonZ | awk '{print $3}';

or

echo cat filename | grep ClNonZ | awk '{print $3}';

How to debug Angular JavaScript Code

Add call to debugger where you intend to use it.

someFunction(){
  debugger;
}

In the console tab of your browser's web developer tools, issue angular.reloadWithDebugInfo();

Visit or reload the page you intend to debug and see the debugger appear in your browser.

How to delete object from array inside foreach loop?

I'm not much of a php programmer, but I can say that in C# you cannot modify an array while iterating through it. You may want to try using your foreach loop to identify the index of the element, or elements to remove, then delete the elements after the loop.

difference between throw and throw new Exception()

If you want you can throw a new Exception, with the original one set as an inner exception.

Key hash for Android-Facebook app

This is what is given at the official page of Facebook:

   keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore | openssl sha1 -binary | openssl base64

Let me break this command into fragments.

  1. Look for "keytool.exe". You can search that on the C: drive. You can find it in "java jdk" or "java jre". If you have installed multiple versions, choose any.

  2. Open a CMD prompt and go to the above directory where you found "keytool.exe".

    Clip the "exe`" and paste the above command provided on the Facebook page.

  3. You will get an error on entering this that OpenSSL is not recognized as in input output command. Solution : Download "Openssl" from OpenSSL (if you have a 64-bit machine you must download openssl-0.9.8e X64). Extract and save it anywhere... I saved it on the C: drive in the OpenSSl folder

  4. Replace the openssl in the above command in which you was getting an error of OpenSSL with "C:\OpenSSL\bin\openssl" at both the places after the pipe, "|".

  5. If prompted for a password, enter android.

And you will get your hash key. For further steps, refer again to the Facebook page.

Remove all stylings (border, glow) from textarea

if no luck with above try to it a class or even id something like textarea.foo and then your style. or try to !important

changing source on html5 video tag

I hated all these answers because they were too short or relied on other frameworks.

Here is "one" vanilla JS way of doing this, working in Chrome, please test in other browsers:

http://jsfiddle.net/mattdlockyer/5eCEu/2/

HTML:

<video id="video" width="320" height="240"></video>

JS:

var video = document.getElementById('video');
var source = document.createElement('source');

source.setAttribute('src', 'http://www.tools4movies.com/trailers/1012/Kill%20Bill%20Vol.3.mp4');

video.appendChild(source);
video.play();

setTimeout(function() {  
    video.pause();

    source.setAttribute('src', 'http://www.tools4movies.com/trailers/1012/Despicable%20Me%202.mp4'); 

    video.load();
    video.play();
}, 3000);

Segmentation fault on large array sizes

Also, if you are running in most UNIX & Linux systems you can temporarily increase the stack size by the following command:

ulimit -s unlimited

But be careful, memory is a limited resource and with great power come great responsibilities :)

How to set "style=display:none;" using jQuery's attr method?

You can use the hide and show functions of jquery. Examples

In your case just set $('#msform').hide() or $('#msform').show()

image processing to improve tesseract OCR accuracy

  1. fix DPI (if needed) 300 DPI is minimum
  2. fix text size (e.g. 12 pt should be ok)
  3. try to fix text lines (deskew and dewarp text)
  4. try to fix illumination of image (e.g. no dark part of image)
  5. binarize and de-noise image

There is no universal command line that would fit to all cases (sometimes you need to blur and sharpen image). But you can give a try to TEXTCLEANER from Fred's ImageMagick Scripts.

If you are not fan of command line, maybe you can try to use opensource scantailor.sourceforge.net or commercial bookrestorer.

Disable keyboard on EditText

You can also use setShowSoftInputOnFocus(boolean) directly on API 21+ or through reflection on API 14+:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
    editText.setShowSoftInputOnFocus(false);
} else {
    try {
        final Method method = EditText.class.getMethod(
                "setShowSoftInputOnFocus"
                , new Class[]{boolean.class});
        method.setAccessible(true);
        method.invoke(editText, false);
    } catch (Exception e) {
        // ignore
    }
}

Git: Remove committed file after push

You can revert only one file to a specified revision.

First you can check on which commits the file was changed.

git log path/to/file.txt

Then you can checkout the file with the revision number.

git checkout 3cdc61015724f9965575ba954c8cd4232c8b42e4 /path/to/file.txt

After that you can commit and push it again.

How do you post data with a link

If you want to pass the data using POST instead of GET, you can do it using a combination of PHP and JavaScript, like this:

function formSubmit(house_number)
{
  document.forms[0].house_number.value = house_number;
  document.forms[0].submit();
}

Then in PHP you loop through the house-numbers, and create links to the JavaScript function, like this:

<form action="house.php" method="POST">
<input type="hidden" name="house_number" value="-1">

<?php
foreach ($houses as $id => name)
{
    echo "<a href=\"javascript:formSubmit($id);\">$name</a>\n";
}
?>
</form>

That way you just have one form whose hidden variable(s) get modified according to which link you click on. Then JavasScript submits the form.

Get the first element of an array

This is not so simple response in the real world. Suppose that we have these examples of possible responses that you can find in some libraries.

$array1 = array();
$array2 = array(1,2,3,4);
$array3 = array('hello'=>'world', 'foo'=>'bar');
$array4 = null;

var_dump('reset1', reset($array1));
var_dump('reset2', reset($array2));
var_dump('reset3', reset($array3));
var_dump('reset4', reset($array4)); // Warning

var_dump('array_shift1', array_shift($array1));
var_dump('array_shift2', array_shift($array2));
var_dump('array_shift3', array_shift($array3));
var_dump('array_shift4', array_shift($array4)); // Warning

var_dump('each1', each($array1));
var_dump('each2', each($array2));
var_dump('each3', each($array3));
var_dump('each4', each($array4)); // Warning

var_dump('array_values1', array_values($array1)[0]); // Notice
var_dump('array_values2', array_values($array2)[0]);
var_dump('array_values3', array_values($array3)[0]);
var_dump('array_values4', array_values($array4)[0]); // Warning

var_dump('array_slice1', array_slice($array1, 0, 1));
var_dump('array_slice2', array_slice($array2, 0, 1));
var_dump('array_slice3', array_slice($array3, 0, 1));
var_dump('array_slice4', array_slice($array4, 0, 1)); // Warning

list($elm) = $array1; // Notice
var_dump($elm);
list($elm) = $array2;
var_dump($elm);
list($elm) = $array3; // Notice
var_dump($elm);
list($elm) = $array4;
var_dump($elm);

Like you can see, we have several 'one line' solutions that work well in some cases, but not in all.

In my opinion, you have should that handler only with arrays.

Now talking about performance, assuming that we have always array, like this:

$elm = empty($array) ? null : ...($array);

...you would use without errors:
$array[count($array)-1];
array_shift
reset
array_values
array_slice

array_shift is faster than reset, that is more fast than [count()-1], and these three are faster than array_values and array_slice.

Pandas create empty DataFrame with only column names

df.to_html() has a columns parameter.

Just pass the columns into the to_html() method.

df.to_html(columns=['A','B','C','D','E','F','G'])

new Runnable() but no new thread?

A thread is something like some branch. Multi-branched means when there are at least two branches. If the branches are reduced, then the minimum remains one. This one is although like the branches removed, but in general we do not consider it branch.

Similarly when there are at least two threads we call it multi-threaded program. If the threads are reduced, the minimum remains one. Hello program is a single threaded program, but no one needs to know multi-threading to write or run it.

In simple words when a program is not said to be having threads, it means that the program is not a multi-threaded program, more over in true sense it is a single threaded program, in which YOU CAN put your code as if it is multi-threaded.

Below a useless code is given, but it will suffice to do away with your some confusions about Runnable. It will print "Hello World".

class NamedRunnable implements Runnable {

    public void run() { // The run method prints a message to standard output.
        System.out.println("Hello World");
    }

    public static void main(String[]arg){ 
        NamedRunnable namedRunnable = new NamedRunnable( );
        namedRunnable.run();
    } 
}

Using JQuery to open a popup window and print

You should put the print function in your view-details.php file and call it once the file is loaded, by either using

<body onload="window.print()"> 

or

$(document).ready(function () { 
  window.print(); 
});

Get rid of "The value for annotation attribute must be a constant expression" message

The value for an annotation must be a compile time constant, so there is no simple way of doing what you are trying to do.

See also here: How to supply value to an annotation from a Constant java

It is possible to use some compile time tools (ant, maven?) to config it if the value is known before you try to run the program.

How can I disable ReSharper in Visual Studio and enable it again?

In ReSharper 8: Tools -> Options -> ReSharper -> Suspend Now

Auto-loading lib files in Rails 4

I think this may solve your problem:

  1. in config/application.rb:

    config.autoload_paths << Rails.root.join('lib')
    

    and keep the right naming convention in lib.

    in lib/foo.rb:

    class Foo
    end
    

    in lib/foo/bar.rb:

    class Foo::Bar
    end
    
  2. if you really wanna do some monkey patches in file like lib/extensions.rb, you may manually require it:

    in config/initializers/require.rb:

    require "#{Rails.root}/lib/extensions" 
    

P.S.

How can I remove a character from a string using JavaScript?

_x000D_
_x000D_
let str = '1234567';
let index = 3;
str = str.substring(0, index) + str.substring(index + 1);
console.log(str) // 123567 - number "4" under index "3" is removed
_x000D_
_x000D_
_x000D_

How can I check if a string contains ANY letters from the alphabet?

Regex should be a fast approach:

re.search('[a-zA-Z]', the_string)

Fixed page header overlaps in-page anchors

Official Bootstrap Adopted Answer:

*[id]:before { 
  display: block; 
  content: " "; 
  margin-top: -75px; // Set the Appropriate Height
  height: 75px; // Set the Appropriate Height
  visibility: hidden; 
}

Credits

Merge

SSRS Field Expression to change the background color of the Cell

=IIF(Fields!Column.Value = "Approved", "Green", "No Color")

How to allow access outside localhost

Mac users:

  1. Go to System Preferences -> Network -> Wi-Fi
  2. Copy the IP address below Status (Usually 192.168.1.x)
  3. Paste it in your ng serve like: ng serve --host 192.168.1.x

Then you must be able to see your page on other devices through 192.168.1.x:4200.

How to get request URL in Spring Boot RestController

Add a parameter of type UriComponentsBuilder to your controller method. Spring will give you an instance that's preconfigured with the URI for the current request, and you can then customize it (such as by using MvcUriComponentsBuilder.relativeTo to point at a different controller using the same prefix).

Displaying output of a remote command with Ansible

Prints pubkey and avoid the changed status by adding changed_when: False to cat task:

- name: Generate SSH keys for vagrant user   
  user: name=vagrant generate_ssh_key=yes ssh_key_bits=2048

- name: Check SSH public key   
  command: /bin/cat $home_directory/.ssh/id_rsa.pub
  register: cat
  changed_when: False

- name: Print SSH public key
  debug: var=cat.stdout

- name: Wait for user to copy SSH public key   
  pause: prompt="Please add the SSH public key above to your GitHub account"

What's the difference between `raw_input()` and `input()` in Python 3?

The difference is that raw_input() does not exist in Python 3.x, while input() does. Actually, the old raw_input() has been renamed to input(), and the old input() is gone, but can easily be simulated by using eval(input()). (Remember that eval() is evil. Try to use safer ways of parsing your input if possible.)

SAP Crystal Reports runtime for .Net 4.0 (64-bit)

I have found a variety of runtimes including Visual Studio(VS) versions are available at http://scn.sap.com/docs/DOC-7824

What is a good pattern for using a Global Mutex in C#?

A solution (for WPF) without WaitOne because it can cause an AbandonedMutexException. This solution uses the Mutex constructor that returns the createdNew boolean to check if the mutex is already created. It also uses the GetType().GUID so renaming an executable doesn't allow multiple instances.

Global vs local mutex see note in: https://docs.microsoft.com/en-us/dotnet/api/system.threading.mutex?view=netframework-4.8

private Mutex mutex;
private bool mutexCreated;

public App()
{
    string mutexId = $"Global\\{GetType().GUID}";
    mutex = new Mutex(true, mutexId, out mutexCreated);
}

protected override void OnStartup(StartupEventArgs e)
{
    base.OnStartup(e);
    if (!mutexCreated)
    {
        MessageBox.Show("Already started!");
        Shutdown();
    }
}

Because Mutex implements IDisposable it is released automatically but for completeness call dispose:

protected override void OnExit(ExitEventArgs e)
{
    base.OnExit(e);
    mutex.Dispose();
}

Move everything into a base class and add the allowEveryoneRule from the accepted answer. Also added ReleaseMutex though it doesn't look like it's really needed because it is released automatically by the OS (what if the application crashes and never calls ReleaseMutex would you need to reboot?).

public class SingleApplication : Application
{
    private Mutex mutex;
    private bool mutexCreated;

    public SingleApplication()
    {
        string mutexId = $"Global\\{GetType().GUID}";

        MutexAccessRule allowEveryoneRule = new MutexAccessRule(
            new SecurityIdentifier(WellKnownSidType.WorldSid, null),
            MutexRights.FullControl, 
            AccessControlType.Allow);
        MutexSecurity securitySettings = new MutexSecurity();
        securitySettings.AddAccessRule(allowEveryoneRule);

        // initiallyOwned: true == false + mutex.WaitOne()
        mutex = new Mutex(initiallyOwned: true, mutexId, out mutexCreated, securitySettings);        
    }

    protected override void OnExit(ExitEventArgs e)
    {
        base.OnExit(e);
        if (mutexCreated)
        {
            try
            {
                mutex.ReleaseMutex();
            }
            catch (ApplicationException ex)
            {
                MessageBox.Show(ex.Message, ex.GetType().FullName, MessageBoxButton.OK, MessageBoxImage.Error);
            }
        }
        mutex.Dispose();
    }

    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);
        if (!mutexCreated)
        {
            MessageBox.Show("Already started!");
            Shutdown();
        }
    }
}

Omit rows containing specific column of NA

Just try this:

DF %>% t %>% na.omit %>% t

It transposes the data frame and omits null rows which were 'columns' before transposition and then you transpose it back.

Java NoSuchAlgorithmException - SunJSSE, sun.security.ssl.SSLContextImpl$DefaultSSLContext

I've had a similar issue with this error. In my case, I was entering the incorrect password for the Keystore.

I changed the password for the Keystore to match what I was entering (I didn't want to change the password I was entering), but it still gave the same error.

keytool -storepasswd -keystore keystore.jks

Problem was that I also needed to change the Key's password within the Keystore.

When I initially created the Keystore, the Key was created with the same password as the Keystore (I accepted this default option). So I had to also change the Key's password as follows:

keytool -keypasswd  -alias my.alias -keystore keystore.jks

Hard reset of a single file

To revert to upstream/master do:

git checkout upstream/master -- myfile.txt

C# MessageBox dialog result

Rather than using if statements might I suggest using a switch instead, I try to avoid using if statements when possible.

var result = MessageBox.Show(@"Do you want to save the changes?", "Confirmation", MessageBoxButtons.YesNoCancel);
switch (result)
{
    case DialogResult.Yes:
        SaveChanges();
        break;
    case DialogResult.No:
        Rollback();
        break;
    default:
        break;
}

cURL equivalent in Node.js?

Since looks like node-curl is dead, I've forked it, renamed, and modified to be more curl like and to compile under Windows.

node-libcurl

Usage example:

var Curl = require( 'node-libcurl' ).Curl;

var curl = new Curl();

curl.setOpt( Curl.option.URL, 'www.google.com' );
curl.setOpt( 'FOLLOWLOCATION', true );

curl.on( 'end', function( statusCode, body, headers ) {

    console.info( statusCode );
    console.info( '---' );
    console.info( body.length );
    console.info( '---' );
    console.info( headers );
    console.info( '---' );
    console.info( this.getInfo( Curl.info.TOTAL_TIME ) );

    this.close();
});

curl.on( 'error', function( err, curlErrorCode ) {

    console.error( err.message );
    console.error( '---' );
    console.error( curlErrorCode );

    this.close();

});

curl.perform();

Perform is async, and there is no way to use it synchronous currently (and probably will never have).

It's still in alpha, but this is going to change soon, and help is appreciated.

Now it's possible to use Easy handle directly for sync requests, example:

var Easy = require( 'node-libcurl' ).Easy,
    Curl = require( 'node-libcurl' ).Curl,
    url = process.argv[2] || 'http://www.google.com',
    ret, ch;

ch = new Easy();

ch.setOpt( Curl.option.URL, url );

ch.setOpt( Curl.option.HEADERFUNCTION, function( buf, size, nmemb ) {

    console.log( buf );

    return size * nmemb;
});

ch.setOpt( Curl.option.WRITEFUNCTION, function( buf, size, nmemb ) {

    console.log( arguments );

    return size * nmemb;
});

// this call is sync!
ret = ch.perform();

ch.close();

console.log( ret, ret == Curl.code.CURLE_OK, Easy.strError( ret ) );

Also, the project is stable now!

When to catch java.lang.Error?

It might be appropriate to catch error within unit tests that check an assertion is made. If someone disables assertions or otherwise deletes the assertion you would want to know

How to print multiple lines of text with Python

I wanted to answer to the following question which is a little bit different than this:

Best way to print messages on multiple lines

He wanted to show lines from repeated characters too. He wanted this output:

----------------------------------------
# Operator Micro-benchmarks
# Run_mode: short
# Num_repeats: 5
# Num_runs: 1000

----------------------------------------

You can create those lines inside f-strings with a multiplication, like this:

run_mode, num_repeats, num_runs = 'short', 5, 1000

s = f"""
{'-'*40}
# Operator Micro-benchmarks
# Run_mode: {run_mode}
# Num_repeats: {num_repeats}
# Num_runs: {num_runs}

{'-'*40}
"""

print(s)

String Padding in C

You must make sure that the input string has enough space to hold all the padding characters. Try this:

char hello[11] = "Hello";
StringPadRight(hello, 10, "0");

Note that I allocated 11 bytes for the hello string to account for the null terminator at the end.

How to create empty text file from a batch file?

fsutil file createnew file.cmd 0

Java decimal formatting using String.format?

Yes you can do it with String.format:

String result = String.format("%.2f", 10.0 / 3.0);
// result:  "3.33"

result = String.format("%.3f", 2.5);
// result:  "2.500"

SQL recursive query on self referencing table (Oracle)

What about using PRIOR,

so

SELECT id, parent_id, PRIOR name
   FROM tbl 
START WITH id = 1 
CONNECT BY PRIOR id = parent_id`

or if you want to get the root name

SELECT id, parent_id, CONNECT_BY_ROOT name
   FROM tbl 
START WITH id = 1 
CONNECT BY PRIOR id = parent_id

Java Replace Line In Text File

just how to replace strings :) as i do first arg will be filename second target string third one the string to be replaced instead of targe

public class ReplaceString{
      public static void main(String[] args)throws Exception {
        if(args.length<3)System.exit(0);
        String targetStr = args[1];
        String altStr = args[2];
        java.io.File file = new java.io.File(args[0]);
        java.util.Scanner scanner = new java.util.Scanner(file);
        StringBuilder buffer = new StringBuilder();
        while(scanner.hasNext()){
          buffer.append(scanner.nextLine().replaceAll(targetStr, altStr));
          if(scanner.hasNext())buffer.append("\n");
        }
        scanner.close();
        java.io.PrintWriter printer = new java.io.PrintWriter(file);
        printer.print(buffer);
        printer.close();
      }
    }

Best timestamp format for CSV/Excel?

For second accuracy, yyyy-MM-dd HH:mm:ss should do the trick.

I believe Excel is not very good with fractions of a second (loses them when interacting with COM object IIRC).

sqlalchemy filter multiple columns

You can simply call filter multiple times:

query = meta.Session.query(User).filter(User.firstname.like(searchVar1)). \
                                 filter(User.lastname.like(searchVar2))

What does "commercial use" exactly mean?

Fundamentally if you use it as part of a business then its commercial use - so its not a matter of whether the tools are directly generating income or not rather one of if they are being used in support of income generation directly or indirectly.

To take your specific example, if the purpose of the site is to sell or promote your paid services/product then its a commercial enterprise.

Using module 'subprocess' with timeout

jcollado's answer can be simplified using the threading.Timer class:

import shlex
from subprocess import Popen, PIPE
from threading import Timer

def run(cmd, timeout_sec):
    proc = Popen(shlex.split(cmd), stdout=PIPE, stderr=PIPE)
    timer = Timer(timeout_sec, proc.kill)
    try:
        timer.start()
        stdout, stderr = proc.communicate()
    finally:
        timer.cancel()

# Examples: both take 1 second
run("sleep 1", 5)  # process ends normally at 1 second
run("sleep 5", 1)  # timeout happens at 1 second

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

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

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

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

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

Is there a typical state machine implementation pattern?

For compiler which support __COUNTER__ , you can use them for simple (but large) state mashines.

  #define START 0      
  #define END 1000

  int run = 1;
  state = START;    
  while(run)
  {
    switch (state)
    {
        case __COUNTER__:
            //do something
            state++;
            break;
        case __COUNTER__:
            //do something
            if (input)
               state = END;
            else
               state++;
            break;
            .
            .
            .
        case __COUNTER__:
            //do something
            if (input)
               state = START;
            else
               state++;
            break;
        case __COUNTER__:
            //do something
            state++;
            break;
        case END:
            //do something
            run = 0;
            state = START;
            break;
        default:
            state++;
            break;
     } 
  } 

The advantage of using __COUNTER__ instead of hard coded numbers is that you can add states in the middle of other states, without renumbering everytime everything. If the compiler doesnt support __COUNTER__, in a limited way its posible to use with precaution __LINE__

Install gitk on Mac

What I ended up doing was: brew info git

Which gave me info that git was cloned into: /usr/local/Cellar/git/1.9.0

So I just added: /usr/local/Cellar/git/1.9.0/bin to the beginning of my PATH env variable.

Note: I don't know how to use homebrew... just want to get going quickly as I have other things to do... this basically gets gitk running for me so I'm sticking to it for now. (probably not the way to work with homebrew though).

List comprehension vs. lambda + filter

This is a somewhat religious issue in Python. Even though Guido considered removing map, filter and reduce from Python 3, there was enough of a backlash that in the end only reduce was moved from built-ins to functools.reduce.

Personally I find list comprehensions easier to read. It is more explicit what is happening from the expression [i for i in list if i.attribute == value] as all the behaviour is on the surface not inside the filter function.

I would not worry too much about the performance difference between the two approaches as it is marginal. I would really only optimise this if it proved to be the bottleneck in your application which is unlikely.

Also since the BDFL wanted filter gone from the language then surely that automatically makes list comprehensions more Pythonic ;-)

Error in Python script "Expected 2D array, got 1D array instead:"?

I use the below approach.

reg = linear_model.LinearRegression()
reg.fit(df[['year']],df.income)

reg.predict([[2136]])

Unable to access JSON property with "-" dash

jsonObj.profile-id is a subtraction expression (i.e. jsonObj.profile - id).

To access a key that contains characters that cannot appear in an identifier, use brackets:

jsonObj["profile-id"]

Laravel Migration Change to Make a Column Nullable

Try it:

$table->integer('user_id')->unsigned()->nullable();

Convert Json Array to normal Java list

Instead of using bundled-in org.json library, try using Jackson or GSON, where this is a one-liner. With Jackson, f.ex:

List<String> list = new ObjectMapper().readValue(json, List.class);
// Or for array:
String[] array = mapper.readValue(json, String[].class);

Delete file from internal storage

This is an old topic, but I will add my experience, maybe someone finds this helpful

>     2019-11-12 20:05:50.178 27764-27764/com.strba.myapplicationx I/File: /storage/emulated/0/Android/data/com.strba.myapplicationx/files/Readings/JPEG_20191112_200550_4444350520538787768.jpg//file when it was created

2019-11-12 20:05:58.801 27764-27764/com.strba.myapplicationx I/File: content://com.strba.myapplicationx.fileprovider/my_images/JPEG_20191112_200550_4444350520538787768.jpg //same file when trying to delete it

solution1:

              Uri uriDelete=Uri.parse (adapter.getNoteAt (viewHolder.getAdapterPosition ()).getImageuri ());//getter getImageuri on my object from adapter that returns String with content uri

here I initialize Content resolver and delete it with a passed parameter of that URI

            ContentResolver contentResolver = getContentResolver ();
            contentResolver.delete (uriDelete,null ,null );

solution2(my first solution-from head in this time I do know that ): content resolver exists...

              String path = "/storage/emulated/0/Android/data/com.strba.myapplicationx/files/Readings/" +
                    adapter.getNoteAt (viewHolder.getAdapterPosition ()).getImageuri ().substring (58);

            File file = new File (path);
            if (file != null) {
                file.delete ();
            }

Hope that this will be helpful to someone happy coding

Google Maps API 3 - Custom marker color for default (dot) marker

Combine a symbol-based marker whose path draws the outline, with a '?' character for the center. You can substitute the dot with other text ('A', 'B', etc.) as desired.

This function returns options for a marker with the a given text (if any), text color, and fill color. It uses the text color for the outline.

function createSymbolMarkerOptions(text, textColor, fillColor) {
    return {
        icon: {
            path: 'M 0,0 C -2,-20 -10,-22 -10,-30 A 10,10 0 1,1 10,-30 C 10,-22 2,-20 0,0 z',
            fillColor: fillColor,
            fillOpacity: 1,
            strokeColor: textColor,
            strokeWeight: 1.8,
            labelOrigin: { x: 0, y: -30 }
        },
        label: {
            text: text || '?',
            color: textColor
        }
    };
}

Difference between .keystore file and .jks file

Ultimately, .keystore and .jks are just file extensions: it's up to you to name your files sensibly. Some application use a keystore file stored in $HOME/.keystore: it's usually implied that it's a JKS file, since JKS is the default keystore type in the Sun/Oracle Java security provider. Not everyone uses the .jks extension for JKS files, because it's implied as the default. I'd recommend using the extension, just to remember which type to specify (if you need).

In Java, the word keystore can have either of the following meanings, depending on the context:

When talking about the file and storage, this is not really a storage facility for key/value pairs (there are plenty or other formats for this). Rather, it's a container to store cryptographic keys and certificates (I believe some of them can also store passwords). Generally, these files are encrypted and password-protected so as not to let this data available to unauthorized parties.

Java uses its KeyStore class and related API to make use of a keystore (whether it's file based or not). JKS is a Java-specific file format, but the API can also be used with other file types, typically PKCS#12. When you want to load a keystore, you must specify its keystore type. The conventional extensions would be:

  • .jks for type "JKS",
  • .p12 or .pfx for type "PKCS12" (the specification name is PKCS#12, but the # is not used in the Java keystore type name).

In addition, BouncyCastle also provides its implementations, in particular BKS (typically using the .bks extension), which is frequently used for Android applications.

How to transfer paid android apps from one google account to another google account

You will not be able to do that. You can download apps again to the same userid account on different devices, but you cannot transfer those licenses to other userids.

There is no way to do this programatically - I don't think you can do that practically (except for trying to call customer support at the Play Store).

Showing all session data at once?

For print session data you do not need to use print_r() function every time .

If you use it then it will be non-readable format.Data will be looks very dirty.

But if you use my function all you have to do is to use p()-Funtion and pass data into it. //create new file into application/cms_helper.php and load helper cms into //autoload or on controller

/*Copy Code for p function from here and paste into cms_helper.php in application/helpers folder */

   //@parram $data-array,$d-if true then die by default it is false
   //@author Your name

    function p($data,$d = false){

          echo "<pre>"; 
             print_r($data);
          echo "</pre>"; 

        if($d == TRUE){
             die();
          } 
      }

Just remember to load cms_helper into your project or controller using $this->load->helper('cms'); use bellow code into your controller or model it will works just GREAT.

 p($this->session->all_userdata()); // it will apply pre to your sesison data and other array as  well

How to use cookies in Python Requests

You can use a session object. It stores the cookies so you can make requests, and it handles the cookies for you

s = requests.Session() 
# all cookies received will be stored in the session object

s.post('http://www...',data=payload)
s.get('http://www...')

Docs: https://requests.readthedocs.io/en/master/user/advanced/#session-objects

You can also save the cookie data to an external file, and then reload them to keep session persistent without having to login every time you run the script:

How to save requests (python) cookies to a file?

Use css gradient over background image

The accepted answer works well. Just for completeness (and since I like it's shortness), I wanted to share how to to it with compass (SCSS/SASS):

body{
  $colorStart: rgba(0,0,0,0);
  $colorEnd: rgba(0,0,0,0.8);
  @include background-image(linear-gradient(to bottom, $colorStart, $colorEnd), url("bg.jpg"));
}

What is the difference between Digest and Basic Authentication?

Let us see the difference between the two HTTP authentication using Wireshark (Tool to analyse packets sent or received) .

1. Http Basic Authentication

Basic

As soon as the client types in the correct username:password,as requested by the Web-server, the Web-Server checks in the Database if the credentials are correct and gives the access to the resource .

Here is how the packets are sent and received :

enter image description here In the first packet the Client fill the credentials using the POST method at the resource - lab/webapp/basicauth .In return the server replies back with http response code 200 ok ,i.e, the username:password were correct .

Detail of HTTP packet

Now , In the Authorization header it shows that it is Basic Authorization followed by some random string .This String is the encoded (Base64) version of the credentials admin:aadd (including colon ) .

2 . Http Digest Authentication(rfc 2069)

So far we have seen that the Basic Authentication sends username:password in plaintext over the network .But the Digest Auth sends a HASH of the Password using Hash algorithm.

Here are packets showing the requests made by the client and response from the server .

Digest

As soon as the client types the credentials requested by the server , the Password is converted to a response using an algorithm and then is sent to the server , If the server Database has same response as given by the client the server gives the access to the resource , otherwise a 401 error .

Detailed digest auth packet In the above Authorization , the response string is calculated using the values of Username,Realm,Password,http-method,URI and Nonce as shown in the image :

Response algorithm (colons are included)

Hence , we can see that the Digest Authentication is more Secure as it involve Hashing (MD5 encryption) , So the packet sniffer tools cannot sniff the Password although in Basic Auth the exact Password was shown on Wireshark.

Want to make Font Awesome icons clickable

In your css add a class:

.fa-clickable {
    cursor:pointer;
    outline:none;
}

Then add the class to the clickable fontawesome icons (also an id so you can differentiate the clicks):

 <i class="fa fa-dribbble fa-4x fa-clickable" id="epd-dribble"></i>
 <i class="fa fa-behance-square fa-4x fa-clickable" id="epd-behance"></i>
 <i class="fa fa-linkedin-square fa-4x fa-clickable" id="epd-linkedin"></i>
 <i class="fa fa-twitter-square fa-4x fa-clickable" id="epd-twitter"></i>
 <i class="fa fa-facebook-square fa-4x fa-clickable" id="epd-facebook"></i>

Then add a handler in your jQuery

$(document).on("click", "i", function(){
    switch (this.id) {
        case "epd-dribble":
            // do stuff
            break;
        // add additional cases
    }
});

Connecting to SQL Server Express - What is my server name?

If sql server is installed on your machine, you should check

Programs -> Microsoft SQL Server 20XX -> Configuration Tools -> SQL Server Configuration Manager -> SQL Server Services You'll see "SQL Server (MSSQLSERVER)"

Programs -> Microsoft SQL Server 20XX -> Configuration Tools -> SQL Server Configuration Manager -> SQL Server Network Configuration -> Protocols for MSSQLSERVER -> TCP/IP Make sure it's using port number 1433

If you want to see if the port is open and listening try this from your command prompt... telnet 127.0.0.1 1433

And yes, SQL Express installs use localhost\SQLEXPRESS as the instance name by default.

Cannot find mysql.sock

Unfortunately none of the above have worked in my case. But finally I found solutions.

To find where is mysql.sock file, simply open xampp manager, select MySQL and click on Configure on the right. On the config panel click Open Conf File, and simply search for mysql.sock by pressing the CMD+F shortcut.

In my case, the owner of the mysql.sock was changed, and I had to change it back to root admin with: chmod root:admin mysql.sock

After that the database had been accessed.

get the data of uploaded file in javascript

you can use the new HTML 5 file api to read file contents

https://developer.mozilla.org/en-US/docs/Using_files_from_web_applications

but this won't work on every browser so you probably need a server side fallback.

String length in bytes in JavaScript

This would work for BMP and SIP/SMP characters.

    String.prototype.lengthInUtf8 = function() {
        var asciiLength = this.match(/[\u0000-\u007f]/g) ? this.match(/[\u0000-\u007f]/g).length : 0;
        var multiByteLength = encodeURI(this.replace(/[\u0000-\u007f]/g)).match(/%/g) ? encodeURI(this.replace(/[\u0000-\u007f]/g, '')).match(/%/g).length : 0;
        return asciiLength + multiByteLength;
    }

    'test'.lengthInUtf8();
    // returns 4
    '\u{2f894}'.lengthInUtf8();
    // returns 4
    '???? ?????'.lengthInUtf8();
    // returns 19, each Arabic/Persian alphabet character takes 2 bytes. 
    '??,JavaScript ??'.lengthInUtf8();
    // returns 26, each Chinese character/punctuation takes 3 bytes. 

How do I remedy "The breakpoint will not currently be hit. No symbols have been loaded for this document." warning?

Because there's file in another project have same name, May be you have two controllers have same name

How to resolve git's "not something we can merge" error

I had the same problem. I fixed it using the command below:

git checkout main
git fetch
git checkout branch_name
git fetch
git checkout main
git fetch
git merge branch_name

Two values from one input in python?

All input will be through a string. It's up to you to process that string after you've received it. Unless that is, you use the eval(input()) method, but that isn't recommended for most situations anyway.

input_string = raw_input("Enter 2 numbers here: ")
a, b = split_string_into_numbers(input_string)
do_stuff(a, b)

Integrate ZXing in Android Studio

I was integrating ZXING into an Android application and there were no good sources for the input all over, I will give you a hint on what worked for me - because it turned out to be very easy.

There is a real handy git repository that provides the zxing android library project as an AAR archive.

All you have to do is add this to your build.gradle

repositories {
    jcenter()
}

dependencies {
    implementation 'com.journeyapps:zxing-android-embedded:3.0.2@aar'
    implementation 'com.google.zxing:core:3.2.0'
}

and Gradle does all the magic to compile the code and makes it accessible in your app.

To start the Scanner afterwards, use this class/method: From the Activity:

new IntentIntegrator(this).initiateScan(); // `this` is the current Activity

From a Fragment:

IntentIntegrator.forFragment(this).initiateScan(); // `this` is the current Fragment
// If you're using the support library, use IntentIntegrator.forSupportFragment(this) instead.

There are several customizing options:

IntentIntegrator integrator = new IntentIntegrator(this);
integrator.setDesiredBarcodeFormats(IntentIntegrator.ONE_D_CODE_TYPES);
integrator.setPrompt("Scan a barcode");
integrator.setCameraId(0);  // Use a specific camera of the device
integrator.setBeepEnabled(false);
integrator.setBarcodeImageEnabled(true);
integrator.initiateScan();

They have a sample-project and are providing several integration examples:

If you already visited the link you going to see that I just copy&pasted the code from the git README. If not, go there to get some more insight and code examples.

Is it possible to use an input value attribute as a CSS selector?

It is possible, if you're using a browser which supports the CSS :valid pseudo-class and the pattern validation attribute on inputs -- which includes most modern browsers except IE9.

For instance, to change the text of an input from black to green when the correct answer is entered:

_x000D_
_x000D_
input {_x000D_
  color: black;_x000D_
}_x000D_
input:valid {_x000D_
  color: green;_x000D_
}
_x000D_
<p>Which country has fifty states?</p>_x000D_
_x000D_
<input type="text" pattern="^United States$">
_x000D_
_x000D_
_x000D_

When should one use a spinlock instead of mutex?

Please also note that on certain environments and conditions (such as running on windows on dispatch level >= DISPATCH LEVEL), you cannot use mutex but rather spinlock. On unix - same thing.

Here is equivalent question on competitor stackexchange unix site: https://unix.stackexchange.com/questions/5107/why-are-spin-locks-good-choices-in-linux-kernel-design-instead-of-something-more

Info on dispatching on windows systems: http://download.microsoft.com/download/e/b/a/eba1050f-a31d-436b-9281-92cdfeae4b45/IRQL_thread.doc

How do I open workbook programmatically as read-only?

Does this work?

Workbooks.Open Filename:=filepath, ReadOnly:=True

Or, as pointed out in a comment, to keep a reference to the opened workbook:

Dim book As Workbook
Set book = Workbooks.Open(Filename:=filepath, ReadOnly:=True)

Autoresize View When SubViews are Added

Yes, it is because you are using auto layout. Setting the view frame and resizing mask will not work.

You should read Working with Auto Layout Programmatically and Visual Format Language.

You will need to get the current constraints, add the text field, adjust the contraints for the text field, then add the correct constraints on the text field.

Pandas Replace NaN with blank/empty string

I tried with one column of string values with nan.

To remove the nan and fill the empty string:

df.columnname.replace(np.nan,'',regex = True)

To remove the nan and fill some values:

df.columnname.replace(np.nan,'value',regex = True)

I tried df.iloc also. but it needs the index of the column. so you need to look into the table again. simply the above method reduced one step.

MySQL: ALTER TABLE if column not exists

Sometimes it may happen that there are multiple schema created in a database.

So to be specific schema we need to target, so this will help to do it.

SELECT count(*) into @colCnt FROM information_schema.columns WHERE table_name = 'mytable' AND column_name = 'mycolumn' and table_schema = DATABASE();
IF @colCnt = 0 THEN
    ALTER TABLE `mytable` ADD COLUMN `mycolumn` VARCHAR(20) DEFAULT NULL;
END IF;

How do I turn off the mysql password validation?

On some installations, you cannot execute this command until you have reset the root password. You cannot reset the root password, until you execute this command. Classic Catch-22.

One solution not mention by other responders is to temporarily disable the plugin via mysql configuration. In any my.cnf, in the [mysqld] section, add:

skip-validate_password=1

and restart the server. Change the password, and set the value back to 0, and restart again.

error: invalid type argument of ‘unary *’ (have ‘int’)

Once you declare the type of a variable, you don't need to cast it to that same type. So you can write a=&b;. Finally, you declared c incorrectly. Since you assign it to be the address of a, where a is a pointer to int, you must declare it to be a pointer to a pointer to int.

#include <stdio.h>
int main(void)
{
    int b=10;
    int *a=&b;
    int **c=&a;
    printf("%d", **c);
    return 0;
} 

How to load image files with webpack file-loader

webpack.config.js

{
    test: /\.(png|jpe?g|gif)$/i,
    loader: 'file-loader',
    options: {
        name: '[name].[ext]',
    },
}

anyfile.html

<img src={image_name.jpg} />

Git - deleted some files locally, how do I get them from a remote repository

If you deleted multiple files locally and did not commit the changes, go to your local repository path, open the git shell and type.

$ git checkout HEAD .

All the deleted files before the last commit will be recovered.

Adding "." will recover all the deleted the files in the current repository, to their respective paths.

For more details checkout the documentation.

How can I get the first two digits of a number?

Comparing the O(n) time solution with the "constant time" O(1) solution provided in other answers goes to show that if the O(n) algorithm is fast enough, n may have to get very large before it is slower than a slow O(1).

The strings version is approx. 60% faster than the "maths" version for numbers of 20 or fewer digits. They become closer only when then number of digits approaches 200 digits

# the "maths" version
import math

def first_n_digits1(num, n):
    return num // 10 ** (int(math.log(num, 10)) - n + 1)

%timeit first_n_digits1(34523452452, 2)
1.21 µs ± 75 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit first_n_digits1(34523452452, 8)
1.24 µs ± 47.5 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

# 22 digits
%timeit first_n_digits1(3423234239472523452452, 2)
1.33 µs ± 59.4 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit first_n_digits1(3423234239472523452452, 15)
1.23 µs ± 61.2 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

# 196 digits
%timeit first_n_digits1(3423234239472523409283475908723908723409872390871243908172340987123409871234012089172340987734507612340981344509873123401234670350981234098123140987314509812734091823509871345109871234098172340987125988123452452, 39)
1.86 µs ± 21.8 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

# The "string" verions
def first_n_digits2(num, n):
    return int(str(num)[:n])

%timeit first_n_digits2(34523452452, 2)
744 ns ± 28.1 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit first_n_digits2(34523452452, 8)
768 ns ± 42.7 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

# 22 digits
%timeit first_n_digits2(3423234239472523452452, 2)
767 ns ± 33.6 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit first_n_digits2(3423234239472523452452, 15)
830 ns ± 55.1 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

# 196 digits
%timeit first_n_digits2(3423234239472523409283475908723908723409872390871243908098712340987123401208917234098773450761234098134450987312340123467035098123409812314098734091823509871345109871234098172340987125988123452452, 39)
1.87 µs ± 140 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

MySQL INNER JOIN Alias

You'll need to join twice:

SELECT home.*, away.*, g.network, g.date_start 
FROM game AS g
INNER JOIN team AS home
  ON home.importid = g.home
INNER JOIN team AS away
  ON away.importid = g.away
ORDER BY g.date_start DESC 
LIMIT 7

PDF to byte array and vice versa

public static void main(String[] args) throws FileNotFoundException, IOException {
        File file = new File("java.pdf");

        FileInputStream fis = new FileInputStream(file);
        //System.out.println(file.exists() + "!!");
        //InputStream in = resource.openStream();
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        byte[] buf = new byte[1024];
        try {
            for (int readNum; (readNum = fis.read(buf)) != -1;) {
                bos.write(buf, 0, readNum); //no doubt here is 0
                //Writes len bytes from the specified byte array starting at offset off to this byte array output stream.
                System.out.println("read " + readNum + " bytes,");
            }
        } catch (IOException ex) {
            Logger.getLogger(genJpeg.class.getName()).log(Level.SEVERE, null, ex);
        }
        byte[] bytes = bos.toByteArray();

        //below is the different part
        File someFile = new File("java2.pdf");
        FileOutputStream fos = new FileOutputStream(someFile);
        fos.write(bytes);
        fos.flush();
        fos.close();
    }

How best to determine if an argument is not sent to the JavaScript function

I'm sorry, I still yet cant comment, so to answer Tom's answer... In javascript (undefined != null) == false In fact that function wont work with "null", you should use "undefined"

React component initialize state from props

You don't need to call setState in a Component's constructor - it's idiomatic to set this.state directly:

class FirstComponent extends React.Component {

  constructor(props) {
    super(props);

    this.state = {
      x: props.initialX
    };
  }
  // ...
}

See React docs - Adding Local State to a Class.

There is no advantage to the first method you describe. It will result in a second update immediately before mounting the component for the first time.

Redis: How to access Redis log file

You can also login to the redis-cli and use the MONITOR command to see what queries are happening against Redis.

Objective-C: Extract filename from path string

Taken from the NSString reference, you can use :

NSString *theFileName = [[string lastPathComponent] stringByDeletingPathExtension];

The lastPathComponent call will return thefile.ext, and the stringByDeletingPathExtension will remove the extension suffix from the end.

Convert Iterable to Stream using Java 8 JDK

If you can use Guava library, since version 21, you can use

Streams.stream(iterable)

Spring MVC - How to return simple String as JSON in Rest Controller

In one project we addressed this using JSONObject (maven dependency info). We chose this because we preferred returning a simple String rather than a wrapper object. An internal helper class could easily be used instead if you don't want to add a new dependency.

Example Usage:

@RestController
public class TestController
{
    @RequestMapping("/getString")
    public String getString()
    {
        return JSONObject.quote("Hello World");
    }
}

How do I migrate an SVN repository with history to a new Git repository?

I suggest getting comfortable with Git before trying to use git-svn constantly, i.e. keeping SVN as the centralized repo and using Git locally.

However, for a simple migration with all the history, here are the few simple steps:

Initialize the local repo:

mkdir project
cd project
git svn init http://svn.url

Mark how far back you want to start importing revisions:

git svn fetch -r42

(or just "git svn fetch" for all revs)

Actually fetch everything since then:

git svn rebase

You can check the result of the import with Gitk. I'm not sure if this works on Windows, it works on OSX and Linux:

gitk

When you've got your SVN repo cloned locally, you may want to push it to a centralized Git repo for easier collaboration.

First create your empty remote repo (maybe on GitHub?):

git remote add origin [email protected]:user/project-name.git

Then, optionally sync your main branch so the pull operation will automatically merge the remote master with your local master, when both contain new stuff:

git config branch.master.remote origin
git config branch.master.merge refs/heads/master

After that, you may be interested in trying out my very own git_remote_branch tool, which helps dealing with remote branches:

First explanatory post: "Git remote branches"

Follow-up for the most recent version: "Time to git collaborating with git_remote_branch"

Gson: Directly convert String to JsonObject (no POJO)

The JsonParser constructor has been deprecated. Use the static method instead:

JsonObject asJsonObject = JsonParser.parseString(request.schema).getAsJsonObject();

Where is `%p` useful with printf?

They do not do the same thing. The latter printf statement interprets b as an unsigned int, which is wrong, as b is a pointer.

Pointers and unsigned ints are not always the same size, so these are not interchangeable. When they aren't the same size (an increasingly common case, as 64-bit CPUs and operating systems become more common), %x will only print half of the address. On a Mac (and probably some other systems), that will ruin the address; the output will be wrong.

Always use %p for pointers.

ascending/descending in LINQ - can one change the order via parameter?

In terms of how this is implemented, this changes the method - from OrderBy/ThenBy to OrderByDescending/ThenByDescending. However, you can apply the sort separately to the main query...

var qry = from .... // or just dataList.AsEnumerable()/AsQueryable()

if(sortAscending) {
    qry = qry.OrderBy(x=>x.Property);
} else {
    qry = qry.OrderByDescending(x=>x.Property);
}

Any use? You can create the entire "order" dynamically, but it is more involved...

Another trick (mainly appropriate to LINQ-to-Objects) is to use a multiplier, of -1/1. This is only really useful for numeric data, but is a cheeky way of achieving the same outcome.

How to write data to a JSON file using Javascript

Unfortunatelly, today (September 2018) you can not find cross-browser solution for client side file writing.

For example: in some browser like a Chrome we have today this possibility and we can write with FileSystemFileEntry.createWriter() with client side call, but according to the docu:

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


For IE (but not MS Edge) we could use ActiveX too, but this is only for this client.

If you want update your JSON file cross-browser you have to use server and client side together.

The client side script

On client side you can make a request to the server and then you have to read the response from server. Or you could read a file with FileReader too. For the cross-browser writing to the file you have to have some server (see below on server part).

var xhr = new XMLHttpRequest(),
    jsonArr,
    method = "GET",
    jsonRequestURL = "SOME_PATH/jsonFile/";

xhr.open(method, jsonRequestURL, true);
xhr.onreadystatechange = function()
{
    if(xhr.readyState == 4 && xhr.status == 200)
    {
        // we convert your JSON into JavaScript object
        jsonArr = JSON.parse(xhr.responseText);

        // we add new value:
        jsonArr.push({"nissan": "sentra", "color": "green"});

        // we send with new request the updated JSON file to the server:
        xhr.open("POST", jsonRequestURL, true);
        xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        // if you want to handle the POST response write (in this case you do not need it):
        // xhr.onreadystatechange = function(){ /* handle POST response */ };
        xhr.send("jsonTxt="+JSON.stringify(jsonArr));
        // but on this place you have to have a server for write updated JSON to the file
    }
};
xhr.send(null);

Server side scripts

You can use a lot of different servers, but I would like to write about PHP and Node.js servers.

By using searching machine you could find "free PHP Web Hosting*" or "free Node.js Web Hosting". For PHP server I would recommend 000webhost.com and for Node.js I would recommend to see and to read this list.

PHP server side script solution

The PHP script for reading and writing from JSON file:

<?php

// This PHP script must be in "SOME_PATH/jsonFile/index.php"

$file = 'jsonFile.txt';

if($_SERVER['REQUEST_METHOD'] === 'POST')
// or if(!empty($_POST))
{
    file_put_contents($file, $_POST["jsonTxt"]);
    //may be some error handeling if you want
}
else if($_SERVER['REQUEST_METHOD'] === 'GET')
// or else if(!empty($_GET))
{
    echo file_get_contents($file);
    //may be some error handeling if you want
}
?>

Node.js server side script solution

I think that Node.js is a little bit complex for beginner. This is not normal JavaScript like in browser. Before you start with Node.js I would recommend to read one from two books:

The Node.js script for reading and writing from JSON file:

var http = require("http"),
    fs = require("fs"),
    port = 8080,
    pathToJSONFile = '/SOME_PATH/jsonFile.txt';

http.createServer(function(request, response)
{
    if(request.method == 'GET')
    {
        response.writeHead(200, {"Content-Type": "application/json"});
        response.write(fs.readFile(pathToJSONFile, 'utf8'));
        response.end();
    }
    else if(request.method == 'POST')
    {
        var body = [];

        request.on('data', function(chunk)
        {
            body.push(chunk);
        });

        request.on('end', function()
        {
            body = Buffer.concat(body).toString();
            var myJSONdata = body.split("=")[1];
            fs.writeFileSync(pathToJSONFile, myJSONdata); //default: 'utf8'
        });
    }
}).listen(port);

Related links for Node.js:

How to fix: "You need to use a Theme.AppCompat theme (or descendant) with this activity"

u should add a theme to ur all activities (u should add theme for all application in ur <application> in ur manifest) but if u have set different theme to ur activity u can use :

 android:theme="@style/Theme.AppCompat"

or each kind of AppCompat theme!

Angular Directive refresh on parameter change

What you're trying to do is to monitor the property of attribute in directive. You can watch the property of attribute changes using $observe() as follows:

angular.module('myApp').directive('conversation', function() {
  return {
    restrict: 'E',
    replace: true,
    compile: function(tElement, attr) {
      attr.$observe('typeId', function(data) {
            console.log("Updated data ", data);
      }, true);

    }
  };
});

Keep in mind that I used the 'compile' function in the directive here because you haven't mentioned if you have any models and whether this is performance sensitive.

If you have models, you need to change the 'compile' function to 'link' or use 'controller' and to monitor the property of a model changes, you should use $watch(), and take of the angular {{}} brackets from the property, example:

<conversation style="height:300px" type="convo" type-id="some_prop"></conversation>

And in the directive:

angular.module('myApp').directive('conversation', function() {
  return {
    scope: {
      typeId: '=',
    },
    link: function(scope, elm, attr) {

      scope.$watch('typeId', function(newValue, oldValue) {
          if (newValue !== oldValue) {
            // You actions here
            console.log("I got the new value! ", newValue);
          }
      }, true);

    }
  };
});

cmake error 'the source does not appear to contain CMakeLists.txt'

You should do mkdir build and cd build while inside opencv folder, not the opencv-contrib folder. The CMakeLists.txt is there.

Java: Casting Object to Array type

What you've got (according to the debug image) is an object array containing a string array. So you need something like:

Object[] objects = (Object[]) values;
String[] strings = (String[]) objects[0];

You haven't shown the type of values - if this is already Object[] then you could just use (String[])values[0].

Of course even with the cast to Object[] you could still do it in one statement, but it's ugly:

String[] strings = (String[]) ((Object[])values)[0];

How to debug Google Apps Script (aka where does Logger.log log to?)

2017 Update: Stackdriver Logging is now available for Google Apps Script. From the menu bar in the script editor, goto: View > Stackdriver Logging to view or stream the logs.

console.log() will write DEBUG level messages

Example onEdit() logging:

function onEdit (e) {
  var debug_e = {
    authMode:  e.authMode,  
    range:  e.range.getA1Notation(),    
    source:  e.source.getId(),
    user:  e.user,   
    value:  e.value,
    oldValue: e. oldValue
  }

  console.log({message: 'onEdit() Event Object', eventObject: debug_e});
}

Then check the logs in the Stackdriver UI labeled onEdit() Event Object to see the output

How to implement a Boolean search with multiple columns in pandas

the query() method can do that very intuitively. Express your condition in a string to be evaluated like the following example :

df = df.query("columnNameA <= @x or columnNameB == @y")

with x and y are declared variables which you can refer to with @

ERROR: Sonar server 'http://localhost:9000' can not be reached

You should configure the sonar-runner to use your existing SonarQube server. To do so, you need to update its conf/sonar-runner.properties file and specify the SonarQube server URL, username, password, and JDBC URL as well. See https://docs.sonarqube.org/display/SCAN/Analyzing+with+SonarQube+Scanner for details.

If you don't yet have an up and running SonarQube server, then you can launch one locally (with the default configuration) - it will bind to http://localhost:9000 and work with the default sonar-runner configuration. See https://docs.sonarqube.org/latest/setup/get-started-2-minutes/ for details on how to get started with the SonarQube server.

Change the value in app.config file dynamically

Expanding on Adis H's example to include the null case (got bit on this one)

 Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            if (config.AppSettings.Settings["HostName"] != null)
                config.AppSettings.Settings["HostName"].Value = hostName;
            else                
                config.AppSettings.Settings.Add("HostName", hostName);                
            config.Save(ConfigurationSaveMode.Modified);
            ConfigurationManager.RefreshSection("appSettings");

Excel SUMIF between dates

One more solution when you want to use data from any sell ( in the key C3)

=SUMIF(Sheet6!M:M;CONCATENATE("<";TEXT(C3;"dd.mm.yyyy"));Sheet6!L:L)

Get today date in google appScript

Utilities.formatDate(new Date(), "GMT+1", "dd/MM/yyyy")

You can change the format by doing swapping the values.

  • dd = day(31)
  • MM = Month(12) - Case sensitive
  • yyyy = Year(2017)
function changeDate() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(GA_CONFIG);
    // You could use now Date(); on its own but it will not look nice.
    var date = Utilities.formatDate(new Date(), "GMT+1", "dd/MM/yyyy")
    var endDate = date
}

Understanding dispatch_async

All of the DISPATCH_QUEUE_PRIORITY_X queues are concurrent queues (meaning they can execute multiple tasks at once), and are FIFO in the sense that tasks within a given queue will begin executing using "first in, first out" order. This is in comparison to the main queue (from dispatch_get_main_queue()), which is a serial queue (tasks will begin executing and finish executing in the order in which they are received).

So, if you send 1000 dispatch_async() blocks to DISPATCH_QUEUE_PRIORITY_DEFAULT, those tasks will start executing in the order you sent them into the queue. Likewise for the HIGH, LOW, and BACKGROUND queues. Anything you send into any of these queues is executed in the background on alternate threads, away from your main application thread. Therefore, these queues are suitable for executing tasks such as background downloading, compression, computation, etc.

Note that the order of execution is FIFO on a per-queue basis. So if you send 1000 dispatch_async() tasks to the four different concurrent queues, evenly splitting them and sending them to BACKGROUND, LOW, DEFAULT and HIGH in order (ie you schedule the last 250 tasks on the HIGH queue), it's very likely that the first tasks you see starting will be on that HIGH queue as the system has taken your implication that those tasks need to get to the CPU as quickly as possible.

Note also that I say "will begin executing in order", but keep in mind that as concurrent queues things won't necessarily FINISH executing in order depending on length of time for each task.

As per Apple:

https://developer.apple.com/library/content/documentation/General/Conceptual/ConcurrencyProgrammingGuide/OperationQueues/OperationQueues.html

A concurrent dispatch queue is useful when you have multiple tasks that can run in parallel. A concurrent queue is still a queue in that it dequeues tasks in a first-in, first-out order; however, a concurrent queue may dequeue additional tasks before any previous tasks finish. The actual number of tasks executed by a concurrent queue at any given moment is variable and can change dynamically as conditions in your application change. Many factors affect the number of tasks executed by the concurrent queues, including the number of available cores, the amount of work being done by other processes, and the number and priority of tasks in other serial dispatch queues.

Basically, if you send those 1000 dispatch_async() blocks to a DEFAULT, HIGH, LOW, or BACKGROUND queue they will all start executing in the order you send them. However, shorter tasks may finish before longer ones. Reasons behind this are if there are available CPU cores or if the current queue tasks are performing computationally non-intensive work (thus making the system think it can dispatch additional tasks in parallel regardless of core count).

The level of concurrency is handled entirely by the system and is based on system load and other internally determined factors. This is the beauty of Grand Central Dispatch (the dispatch_async() system) - you just make your work units as code blocks, set a priority for them (based on the queue you choose) and let the system handle the rest.

So to answer your above question: you are partially correct. You are "asking that code" to perform concurrent tasks on a global concurrent queue at the specified priority level. The code in the block will execute in the background and any additional (similar) code will execute potentially in parallel depending on the system's assessment of available resources.

The "main" queue on the other hand (from dispatch_get_main_queue()) is a serial queue (not concurrent). Tasks sent to the main queue will always execute in order and will always finish in order. These tasks will also be executed on the UI Thread so it's suitable for updating your UI with progress messages, completion notifications, etc.

AWK: Access captured group from line pattern

That was a stroll down memory lane...

I replaced awk by perl a long time ago.

Apparently the AWK regular expression engine does not capture its groups.

you might consider using something like :

perl -n -e'/test(\d+)/ && print $1'

the -n flag causes perl to loop over every line like awk does.

hasNext in Python iterators?

very interesting question, but this "hasnext" design had been put into leetcode: https://leetcode.com/problems/iterator-for-combination/

here is my implementation:

class CombinationIterator:

def __init__(self, characters: str, combinationLength: int):
    from itertools import combinations
    from collections import deque
    self.iter = combinations(characters, combinationLength)
    self.res = deque()


def next(self) -> str:
    if len(self.res) == 0:
        return ''.join(next(self.iter))
    else:
        return ''.join(self.res.pop())


def hasNext(self) -> bool:
    try:
        self.res.insert(0, next(self.iter))
        return True
    except:
        return len(self.res) > 0

PHP unable to load php_curl.dll extension

In PHP 5.6.x version You should do the following:

Move to Windows\system32 folder DLLs from php folder:

libssh2.dll, ssleay32.dll, libeay32.dll and php_curl.dll from php ext folder

Move to Apache24\bin folder from php folder:

libssh2.dll

Also, don't forget to uncomment extension=php_curl.dll in php.ini

Using cut command to remove multiple columns

The same could be done with Perl
Because it uses 0-based-indexing instead of 1-based-indexing, the field values are offset by 1

perl -F, -lane 'print join ",", @F[1..3,5..9,11..19]'    

is equivalent to:

cut -d, -f2-4,6-10,12-20

If the commas are not needed in the output:

perl -F, -lane 'print "@F[1..3,5..9,11..19]"'

How do you launch the JavaScript debugger in Google Chrome?

These are the tools you see

Press the F12

developer tools

Completely Remove MySQL Ubuntu 14.04 LTS

Different solution for those still having issues. Hopefully I can help those trying to reinstall Mysql. Note, It's a seek and destroy mission. So be weary. Assuming your root:

apt-get purge mysql*
apt-get purge dbconfig-common #the screen used for mysql password
find / -name *mysql*          #delete any traces of mysql
#insert apt-get cleanups, autoremove,updates etc.

Originally, something leftover was interfering with my startup of mysqlserver-5.5. These commands ended up resolving the issue for myself.

Maven 3 Archetype for Project With Spring, Spring MVC, Hibernate, JPA

Possible duplicate: Is there a maven 2 archetype for spring 3 MVC applications?

That said, I would encourage you to think about making your own archetype. The reason is, no matter what you end up getting from someone else's, you can do better in not that much time, and a decent sized Java project is going to end up making a lot of jar projects.

Printing integer variable and string on same line in SQL

Double check if you have set and initial value for int and decimal values to be printed.

This sample is printing an empty line

declare @Number INT
print 'The number is : ' + CONVERT(VARCHAR, @Number)

And this sample is printing -> The number is : 1

declare @Number INT = 1
print 'The number is : ' + CONVERT(VARCHAR, @Number)

What are Long-Polling, Websockets, Server-Sent Events (SSE) and Comet?

Tieme put a lot of effort into his excellent answer, but I think the core of the OP's question is how these technologies relate to PHP rather than how each technology works.

PHP is the most used language in web development besides the obvious client side HTML, CSS, and Javascript. Yet PHP has 2 major issues when it comes to real-time applications:

  1. PHP started as a very basic CGI. PHP has progressed very far since its early stage, but it happened in small steps. PHP already had many millions of users by the time it became the embed-able and flexible C library that it is today, most of whom were dependent on its earlier model of execution, so it hasn't yet made a solid attempt to escape the CGI model internally. Even the command line interface invokes the PHP library (libphp5.so on Linux, php5ts.dll on Windows, etc) as if it still a CGI processing a GET/POST request. It still executes code as if it just has to build a "page" and then end its life cycle. As a result, it has very little support for multi-thread or event-driven programming (within PHP userspace), making it currently unpractical for real-time, multi-user applications.

Note that PHP does have extensions to provide event loops (such as libevent) and threads (such as pthreads) in PHP userspace, but very, very, few of the applications use these.

  1. PHP still has significant issues with garbage collection. Although these issues have been consistently improving (likely its greatest step to end the life cycle as described above), even the best attempts at creating long-running PHP applications require being restarted on a regular basis. This also makes it unpractical for real-time applications.

PHP 7 will be a great step to fix these issues as well, and seems very promising as a platform for real-time applications.

Get the number of rows in a HTML table

Well it depends on what you have in your table.

its one of the following If you have only one table

var count = $('#gvPerformanceResult tr').length;

If you are concerned about sub tables but this wont work with tbody and thead (if you use them)

var count = $('#gvPerformanceResult>tr').length;

Where by this will work (but is quite frankly overkill.)

var count = $('#gvPerformanceResult>tbody>tr').length;

Common sources of unterminated string literal

I've had trouble with angled quotes in the past ( ‘ ) usually from copy and pasting from Word. Replacing them with regular single quotes ( ' ) does the trick.

Android - drawable with rounded corners at the top only

Building upon busylee's answer, this is how you can make a drawable that only has one unrounded corner (top-left, in this example):

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <solid android:color="@color/white" />
            <!-- A numeric value is specified in "radius" for demonstrative purposes only,
                  it should be @dimen/val_name -->
            <corners android:radius="10dp" />
        </shape>
    </item>
    <!-- To keep the TOP-LEFT corner UNROUNDED set both OPPOSITE offsets (bottom+right): -->
    <item
        android:bottom="10dp"
        android:right="10dp">
        <shape android:shape="rectangle">
            <solid android:color="@color/white" />
        </shape>
    </item>
</layer-list>

Please note that the above drawable is not shown correctly in the Android Studio preview (2.0.0p7). To preview it anyway, create another view and use this as android:background="@drawable/...".

Is std::vector copying the objects with a push_back?

Yes, std::vector stores copies. How should vector know what the expected life-times of your objects are?

If you want to transfer or share ownership of the objects use pointers, possibly smart pointers like shared_ptr (found in Boost or TR1) to ease resource management.

Angularjs: Get element in controller

Create custom directive

masterApp.directive('ngRenderCallback', function() {
    return {
        restrict: "A",
        link: function ($scope, element, attrs) {
            setTimeout(function(){ 
                $scope[attrs.ngEl] = element[0];
                $scope.$eval(attrs.ngRenderCallback);               
            }, 30);
        }
    }
});

code for html template

<div ng-render-callback="fnRenderCarousel('carouselA')" ng-el="carouselA"></div>

function in controller

$scope.fnRenderCarousel = function(elName){
    $($scope[elName]).carousel();
}

Count number of occurrences for each unique value

If i am understanding your question, would this work? (you will have to replace with your actual column and table names)

SELECT time_col, COUNT(time_col) As Count
FROM time_table
GROUP BY time_col
WHERE activity_col = 3

Selecting default item from Combobox C#

private void comboBox_Loaded(object sender, RoutedEventArgs e)
{
 Combobox.selectedIndex= your index;
}

OR if you want to display some value after comparing into combobox

 foreach (var item in comboBox.Items)
            {
                if (item.ToString().ToLower().Equals("your item in lower"))
                {
                    comboBox.SelectedValue = item;
                }
            }

I hope it will help, it works for me.

How to copy directories in OS X 10.7.3?

Is there something special with that directory or are you really just asking how to copy directories?

Copy recursively via CLI:

cp -R <sourcedir> <destdir>

If you're only seeing the files under the sourcedir being copied (instead of sourcedir as well), that's happening because you kept the trailing slash for sourcedir:

cp -R <sourcedir>/ <destdir>

The above only copies the files and their directories inside of sourcedir. Typically, you want to include the directory you're copying, so drop the trailing slash:

cp -R <sourcedir> <destdir>

AngularJS : Prevent error $digest already in progress when calling $scope.$apply()

You can use $timeout to prevent the error.

$timeout(function () {
    var scope = angular.element($("#myController")).scope();
    scope.myMethod(); 
    scope.$scope();
}, 1);

How can I symlink a file in Linux?

How to create symlink in vagrant. Steps:

  1. In vagrant file create a synced folder. e.g config.vm.synced_folder "F:/Sunburst/source/sunburst/lms", "/source" F:/Sunburst/source/sunburst/lms :- where the source code, /source :- directory path inside the vagrant
  2. Vagrant up and type vagrant ssh and go to source directory e.g cd source
  3. Verify your source code folder structure is available in the source directory. e.g /source/local
  4. Then go to the guest machine directory where the files which are associate with the browser. After get backup of the file. e.g sudo mv local local_bk
  5. Then create symlink e.g sudo ln -s /source/local local. local mean link-name (folder name in guest machine which you are going to link) if you need to remove the symlink :- Type sudo rm local

How can I convert String to Int?

You can convert a string to int in C# using:

Functions of convert class i.e. Convert.ToInt16(), Convert.ToInt32(), Convert.ToInt64() or by using Parse and TryParse Functions. Examples are given here.

How to wait for the 'end' of 'resize' event and only then perform an action?

Here is VERY simple script to trigger both a 'resizestart' and 'resizeend' event on the window object.

There is no need to muck around with dates and times.

The d variable represents the number of milliseconds between resize events before triggering the resize end event, you can play with this to change how sensitive the end event is.

To listen to these events all you need to do is:

resizestart: $(window).on('resizestart', function(event){console.log('Resize Start!');});

resizeend: $(window).on('resizeend', function(event){console.log('Resize End!');});

(function ($) {
    var d = 250, t = null, e = null, h, r = false;

    h = function () {
        r = false;
        $(window).trigger('resizeend', e);
    };

    $(window).on('resize', function (event) {
        e = event || e;
        clearTimeout(t);

        if (!r) {
            $(window).trigger('resizestart', e);
            r = true;
        }

        t = setTimeout(h, d);
    });
}(jQuery));

error: invalid initialization of non-const reference of type ‘int&’ from an rvalue of type ‘int’

12 is a compile-time constant which can not be changed unlike the data referenced by int&. What you can do is

const int& z = 12;

How do I set vertical space between list items?

you can also use the line-height property on the ul

_x000D_
_x000D_
ul {
  line-height: 45px;
}
_x000D_
<ul>
<li>line one</li>
<li>line two</li>
<li>line three</li>
</ul>
_x000D_
_x000D_
_x000D_

What is ":-!!" in C code?

It's creating a size 0 bitfield if the condition is false, but a size -1 (-!!1) bitfield if the condition is true/non-zero. In the former case, there is no error and the struct is initialized with an int member. In the latter case, there is a compile error (and no such thing as a size -1 bitfield is created, of course).

specifying goal in pom.xml

I am facing same Issue after run my build.

The error message tell us to specify your goal

Jenkins Issue related to goal for build

So I specify the goal Ex:-test.

Now It's running fine

How do you resize a form to fit its content automatically?

You could calculate the required height of the TreeView, by figuring out the height of a node, multiplying it by the number of nodes, then setting the form's MinimumSize property accordingly.

// assuming the treeview is populated!
nodeHeight = treeview1.Nodes[0].Bounds.Height;

this.MaximumSize = new Size(someMaximumWidth, someMaximumHeight);

int requiredFormHeight = (treeView1.GetNodeCount(true) * nodeHeight);

this.MinimumSize = new Size(this.Width, requiredFormHeight);

NB. This assumes though that the treeview1 is the only control on the form. When setting the requiredFormHeight variable you'll need to allow for other controls and height requirements surrounding the treeview, such as the tabcontrol you mentioned.

(I would however agree with @jgauffin and assess the rationale behind the requirement to resize a form everytime it loads without the user's consent - maybe let the user position and size the form and remember that instead??)

TypeError: 'tuple' object does not support item assignment when swapping values

Evaluating "1,2,3" results in (1, 2, 3), a tuple. As you've discovered, tuples are immutable. Convert to a list before processing.

How do I set the default font size in Vim?

For the first one remove the spaces. Whitespace matters for the set command.

set guifont=Monaco:h20

For the second one it should be (the h specifies the height)

set guifont=Monospace:h20

My recommendation for setting the font is to do (if your version supports it)

set guifont=*

This will pop up a menu that allows you to select the font. After selecting the font, type

set guifont?

To show what the current guifont is set to. After that copy that line into your vimrc or gvimrc. If there are spaces in the font add a \ to escape the space.

set guifont=Monospace\ 20

Converting a double to an int in C#

you can round your double and cast ist:

(int)Math.Round(myDouble);

How do I escape a string inside JavaScript code inside an onClick handler?

Declare separate functions in the <head> section and invoke those in your onClick method. If you have lots you could use a naming scheme that numbers them, or pass an integer in in your onClicks and have a big fat switch statement in the function.

Spring Could not Resolve placeholder

Hopefully it will be still helpful, the application.properties (or application.yml) file must be in both the paths:

  • src/main/resource/config
  • src/test/resource/config

containing the same property you are referring

What is the difference between require and require-dev sections in composer.json?

General rule is that you want packages from require-dev section only in development (dev) environments, for example local environment.

Packages in require-dev section are packages which help you debug app, run tests etc.

At staging and production environment you probably want only packages from require section.

But anyway you can run composer install --no-dev and composer update --no-dev on any environment, command will install only packages from required section not from require-dev, but probably you want to run this only at staging and production environments not on local.

Theoretically you can put all packages in require section and nothing will happened, but you don't want developing packages at production environment because of the following reasons :

  1. speed
  2. potential of expose some debuging info
  3. etc

Some good candidates for require-dev are :

"filp/whoops": "^2.0",
"fzaninotto/faker": "^1.4",
"mockery/mockery": "^1.0",
"nunomaduro/collision": "^2.0",
"phpunit/phpunit": "^7.0"

you can see what above packages are doing and you will see why you don't need them on production.

See more here : https://getcomposer.org/doc/04-schema.md

SQL Server datetime LIKE select?

There's no direct support for LIKE operator against DATETIME variables, but you can always cast the DATETIME to a VARCHAR:

SELECT (list of fields) FROM YourTable
WHERE CONVERT(VARCHAR(25), register_date, 126) LIKE '2009-10-10%'

Check the MSDN docs for a complete list of available "styles" in the CONVERT function.

Marc

Convert seconds value to hours minutes seconds?

Here's my function to address the problem:

public static String getConvertedTime(double time){

    double h,m,s,mil;

    mil = time % 1000;
    s = time/1000;
    m = s/60;
    h = m/60;
    s = s % 60;
    m = m % 60;
    h = h % 24;

    return ((int)h < 10 ? "0"+String.valueOf((int)h) : String.valueOf((int)h))+":"+((int)m < 10 ? "0"+String.valueOf((int)m) : String.valueOf((int)m))
            +":"+((int)s < 10 ? "0"+String.valueOf((int)s) : String.valueOf((int)s))
            +":"+((int)mil > 100 ? String.valueOf((int)mil) : (int)mil > 9 ? "0"+String.valueOf((int)mil) : "00"+String.valueOf((int)mil));
}

Negative list index?

Negative numbers mean that you count from the right instead of the left. So, list[-1] refers to the last element, list[-2] is the second-last, and so on.

How to get the indexpath.row when an element is activated?

For Swift2.1

I found a way to do it, hopefully, it'll help.

let point = tableView.convertPoint(CGPoint.zero, fromView: sender)

    guard let indexPath = tableView.indexPathForRowAtPoint(point) else {
        fatalError("can't find point in tableView")
    }

Forking vs. Branching in GitHub

Forking creates an entirely new repository from existing repository (simply doing git clone on gitHub/bitbucket)

Forks are best used: when the intent of the ‘split’ is to create a logically independent project, which may never reunite with its parent.

Branch strategy creates a new branch over the existing/working repository

Branches are best used: when they are created as temporary places to work through a feature, with the intent to merge the branch with the origin.

More Specific :- In open source projects it is the owner of the repository who decides who can push to the repository. However, the idea of open source is that everybody can contribute to the project.

This problem is solved by forks: any time a developer wants to change something in an open source project, they don’t clone the official repository directly. Instead, they fork it to create a copy. When the work is finished, they make a pull request so that the owner of the repository can review the changes and decide whether to merge them to his project.

At its core forking is similar to feature branching, but instead of creating branches a fork of the repository is made, and instead of doing a merge request you create a pull request.

The below links provide the difference in a well-explained manner :

https://blog.gitprime.com/the-definitive-guide-to-forks-and-branches-in-git/

https://buddy.works/blog/5-types-of-git-workflows

http://www.continuousagile.com/unblock/branching.html

How to overwrite the output directory in spark

From the pyspark.sql.DataFrame.save documentation (currently at 1.3.1), you can specify mode='overwrite' when saving a DataFrame:

myDataFrame.save(path='myPath', source='parquet', mode='overwrite')

I've verified that this will even remove left over partition files. So if you had say 10 partitions/files originally, but then overwrote the folder with a DataFrame that only had 6 partitions, the resulting folder will have the 6 partitions/files.

See the Spark SQL documentation for more information about the mode options.

Executors.newCachedThreadPool() versus Executors.newFixedThreadPool()

If you look at the source code, you will see, they are calling ThreadPoolExecutor. internally and setting their properties. You can create your one to have a better control of your requirement.

public static ExecutorService newFixedThreadPool(int nThreads) {
   return new ThreadPoolExecutor(nThreads, nThreads,0L, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>());
}

public static ExecutorService newCachedThreadPool() {
        return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
                                      60L, TimeUnit.SECONDS,
                                      new SynchronousQueue<Runnable>());
}

Keep the order of the JSON keys during JSON conversion to CSV

patchFor(answer @gary) :

$ git diff JSONObject.java                                                         
diff --git a/JSONObject.java b/JSONObject.java
index e28c9cd..e12b7a0 100755
--- a/JSONObject.java
+++ b/JSONObject.java
@@ -32,7 +32,7 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.Collection;
 import java.util.Enumeration;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.Iterator;
 import java.util.Locale;
 import java.util.Map;
@@ -152,7 +152,9 @@ public class JSONObject {
      * Construct an empty JSONObject.
      */
     public JSONObject() {
-        this.map = new HashMap<String, Object>();
+//      this.map = new HashMap<String, Object>();
+        // I want to keep order of the given data:
+        this.map = new LinkedHashMap<String, Object>();
     }

     /**
@@ -243,7 +245,7 @@ public class JSONObject {
      * @throws JSONException
      */
     public JSONObject(Map<String, Object> map) {
-        this.map = new HashMap<String, Object>();
+        this.map = new LinkedHashMap<String, Object>();
         if (map != null) {
             Iterator<Entry<String, Object>> i = map.entrySet().iterator();
             while (i.hasNext()) {

How do I revert my changes to a git submodule?

If you want to do this for all submodules, without having to change directories, you can perform

git submodule foreach git reset --hard

You can also use the recursive flag to apply to all submodules:

git submodule foreach --recursive git reset --hard

Can I set an opacity only to the background image of a div?

I implemented Marcus Ekwall's solution but was able to remove a few things to make it simpler and it still works. Maybe 2017 version of html/css?

html:

<div id="content">
  <div id='bg'></div>
  <h2>What is Lorem Ipsum?</h2>
  <p><strong>Lorem Ipsum</strong> is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen
    book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with
    desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
</div>

css:

#content {
  text-align: left;
  width: 75%;
  margin: auto;
  position: relative;
}

#bg {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background: url('https://static.pexels.com/photos/6644/sea-water-ocean-waves.jpg') center center;
  opacity: .4;
  width: 100%;
  height: 100%;
}

https://jsfiddle.net/abalter/3te9fjL5/

Why is Maven downloading the maven-metadata.xml every time?

Maven does this because your dependency is in a SNAPSHOT version and maven has no way to detect any changes made to that snapshot version in the repository. Release your artifact and change the version in pom.xml to that version and maven will no longer fetch the metadata file.

websocket closing connection automatically

I have a similar experience and I believe that it might be the browser that is cutting the session short. I also set the maxIdleTimeout, but the session is dropped regardless. To me, it looks like it is the client (the browser) that is timing out the session and then hangs up.

Don't know how to work around it.

Getting Chrome to accept self-signed localhost certificate

Click anywhere on the page and type a BYPASS_SEQUENCE

"thisisunsafe" is a BYPASS_SEQUENCE for Chrome version 65

"badidea" Chrome version 62 - 64.

"danger" used to work in earlier versions of Chrome

You don't need to look for input field, just type it. It feels strange but it is working.

I tried it on Mac High Sierra.

To double check if they changed it again go to Latest chromium Source Code

To look for BYPASS_SEQUENCE, at the moment it looks like that:

var BYPASS_SEQUENCE = window.atob('dGhpc2lzdW5zYWZl');

Now they have it camouflaged, but to see the real BYPASS_SEQUENCE you can run following line in a browser console.

console.log(window.atob('dGhpc2lzdW5zYWZl'));

How to convert vector to array

You can do some what like this

vector <int> id;
vector <double> v;

if(id.size() > 0)
{
    for(int i = 0; i < id.size(); i++)
    {
        for(int j = 0; j < id.size(); j++)
        {
            double x = v[i][j];
            cout << x << endl;
        }
    }
}