Programs & Examples On #Evaluation strategy

JavaScript window resize event

window.onresize = function() {
    // your code
};

static const vs #define

Please see here: static const vs define

usually a const declaration (notice it doesn't need to be static) is the way to go

bootstrap datepicker today as default

If none of the above option work, use the following :

$(".datepicker").datepicker();
$(".datepicker").datepicker("setDate", new Date());

This worked for me.

Selenium wait until document is ready

The following code should probably work:

WebDriverWait wait = new WebDriverWait(driver, 10);
wait.until(ExpectedConditions.presenceOfAllElementsLocated(By.xpath("//*")));

PHP - remove <img> tag from string

$this->load->helper('security');
$h=mysql_real_escape_string(strip_image_tags($comment));

If user inputs

<img src="#">

In the database table just insert character this #

Works for me

How to import existing *.sql files in PostgreSQL 8.4?

in command line first reach the directory where psql is present then write commands like this:

psql [database name] [username]

and then press enter psql asks for password give the user password:

then write

> \i [full path and file name with extension]

then press enter insertion done.

Naming conventions for Java methods that return boolean

For methods which may fail, that is you specify boolean as return type, I would use the prefix try:

if (tryCreateFreshSnapshot())
{
  // ...
}

For all other cases use prefixes like is.. has.. was.. can.. allows.. ..

get the selected index value of <select> tag in php

As you said..

$Gender  = isset($_POST["gender"]); ' it returns a empty string 

because, you haven't mention method type either use POST or GET, by default it will use GET method. On the other side, you are trying to retrieve your value by using POST method, but in the form you haven't mentioned POST method. Which means miss-match method will result for empty.

Try this code..

<form name="signup_form"  action="./signup.php" onsubmit="return validateForm()"   method="post">
<table> 
  <tr> <td> First Name    </td><td> <input type="text" name="fname" size=10/></td></tr>
  <tr> <td> Last Name     </td><td> <input type="text" name="lname" size=10/></td></tr>
  <tr> <td> Your Email    </td><td> <input type="text" name="email" size=10/></td></tr>
  <tr> <td> Re-type Email </td><td> <input type="text" name="remail"size=10/></td></tr>
  <tr> <td> Password      </td><td> <input type="password" name="paswod" size=10/> </td></tr>
  <tr> <td> Gender        </td><td> <select name="gender">
  <option value="select">                Select </option>    
  <option value="male">   Male   </option>
  <option value="female"> Female </option></select></td></tr> 
  <tr> <td> <input type="submit" value="Sign up" id="signup"/> </td> </tr>
 </table>
 </form>

and on signup page

$Gender  = $_POST["gender"];

i'm sure.. now, you will get the value..

Issue with background color and Google Chrome

After trying all of the other solutions here without success, I skeptically tried the solution found in this article, and got it to work.

Essentially, it boils down to removing @charset "utf-8"; from your CSS.

This seems like a poor implementation in DreamWeaver - but it did fix the issue for me, regardless.

How to get the size of a varchar[n] field in one SQL statement?

For t-SQL I use the following query for varchar columns (shows the collation and is_null properties):

SELECT
    s.name
    , o.name as table_name
    , c.name as column_name
    , t.name as type
    , c.max_length
    , c.collation_name
    , c.is_nullable
FROM
    sys.columns c
    INNER JOIN sys.objects o ON (o.object_id = c.object_id)
    INNER JOIN sys.schemas s ON (s.schema_id = o.schema_id)
    INNER JOIN sys.types t ON (t.user_type_id = c.user_type_id)
WHERE
    s.name = 'dbo'
    AND t.name IN ('varchar') -- , 'char', 'nvarchar', 'nchar')
ORDER BY
    o.name, c.name

How to Load Ajax in Wordpress

As per your request I have put this in an answer for you.

As Hieu Nguyen suggested in his answer, you can use the ajaxurl javascript variable to reference the admin-ajax.php file. However this variable is not declared on the frontend. It is simple to declare this on the front end, by putting the following in the header.php of your theme.

<script type="text/javascript">
    var ajaxurl = "<?php echo admin_url('admin-ajax.php'); ?>";
</script>

As is described in the Wordpress AJAX documentation, you have two different hooks - wp_ajax_(action), and wp_ajax_nopriv_(action). The difference between these is:

  • wp_ajax_(action): This is fired if the ajax call is made from inside the admin panel.
  • wp_ajax_nopriv_(action): This is fired if the ajax call is made from the front end of the website.

Everything else is described in the documentation linked above. Happy coding!

P.S. Here is an example that should work. (I have not tested)

Front end:

<script type="text/javascript">
    jQuery.ajax({
        url: ajaxurl,
        data: {
            action: 'my_action_name'
        },
        type: 'GET'
    });
</script>

Back end:

<?php
    function my_ajax_callback_function() {
        // Implement ajax function here
    }
    add_action( 'wp_ajax_my_action_name', 'my_ajax_callback_function' );    // If called from admin panel
    add_action( 'wp_ajax_nopriv_my_action_name', 'my_ajax_callback_function' );    // If called from front end
?>

UPDATE Even though this is an old answer, it seems to keep getting thumbs up from people - which is great! I think this may be of use to some people.

WordPress has a function wp_localize_script. This function takes an array of data as the third parameter, intended to be translations, like the following:

var translation = {
    success: "Success!",
    failure: "Failure!",
    error: "Error!",
    ...
};

So this simply loads an object into the HTML head tag. This can be utilized in the following way:

Backend:

wp_localize_script( 'FrontEndAjax', 'ajax', array(
    'url' => admin_url( 'admin-ajax.php' )
) );

The advantage of this method is that it may be used in both themes AND plugins, as you are not hard-coding the ajax URL variable into the theme.

On the front end, the URL is now accessible via ajax.url, rather than simply ajaxurl in the previous examples.

SQL: how to use UNION and order by a specific select?

You want to do this:

select * from 
(
    SELECT id, 2 as ordered FROM a -- returns 1,4,2,3
    UNION
    SELECT id, 1 as ordered FROM b -- returns 2,1
)
order by ordered

Update

I noticed that even though you have two different tables, you join the IDs, that means, if you have 1 in both tables, you are getting only one occurrence. If that's the desired behavior, you should stick to UNION. If not, change to UNION ALL.

So I also notice that if you change to the code I proposed, You would start getting both 1 and 2 (from both a and b). In that case, you might want to change the proposed code to:

select distinct id from 
(
    SELECT id, 2 as ordered FROM a -- returns 1,4,2,3
    UNION
    SELECT id, 1 as ordered FROM b -- returns 2,1
)
order by ordered

How to pass a function as a parameter in Java?

Java does not (yet) support closures. But there are other languages like Scala and Groovy which run in the JVM and do support closures.

Resetting remote to a certain commit

If you want a previous version of file, I would recommend using git checkout.

git checkout <commit-hash>

Doing this will send you back in time, it does not affect the current state of your project, you can come to mainline git checkout mainline

but when you add a file in the argument, that file is brought back to you from a previous time to your current project time, i.e. your current project is changed and needs to be committed.

git checkout <commit-hash> -- file_name
git add .
git commit -m 'file brought from previous time'
git push

The advantage of this is that it does not delete history, and neither does revert a particular code changes (git revert)

Check more here https://www.atlassian.com/git/tutorials/undoing-changes#git-checkout

box-shadow on bootstrap 3 container

http://jsfiddle.net/Y93TX/2/

     @import url("http://netdna.bootstrapcdn.com/bootstrap/3.0.0-wip/css/bootstrap.min.css");

.row {
    height: 100px;
    background-color: green;
}
.container {
    margin-top: 50px;
    box-shadow: 0 0 30px black;
    padding:0 15px 0 15px;
}



    <div class="container">
        <div class="row">one</div>
        <div class="row">two</div>
        <div class="row">three</div>
    </div>
</body>

How can I set NODE_ENV=production on Windows?

To run your application in PowerShell (since && is disallowed):

($env:NODE_ENV="production") -and (node myapp/app.js)

Note that the text output of what the server's doing is suppressed, and I am not sure if that's fixable. (Expanding on @jsalonen's answer.)

Plot multiple boxplot in one graph

In base R a formula interface with interactions (:) can be used to achieve this.

df <- read.csv("~/Desktop/TestData.csv")
df <- data.frame(stack(df[,-1]), Label=df$Label) # reshape to long format

boxplot(values ~ Label:ind, data=df, col=c("red", "limegreen"), las=2)

example

How to get sp_executesql result into a variable?

If you have OUTPUT parameters you can do

DECLARE @retval int   
DECLARE @sSQL nvarchar(500);
DECLARE @ParmDefinition nvarchar(500);

DECLARE @tablename nvarchar(50)  
SELECT @tablename = N'products'  

SELECT @sSQL = N'SELECT @retvalOUT = MAX(ID) FROM ' + @tablename;  
SET @ParmDefinition = N'@retvalOUT int OUTPUT';

EXEC sp_executesql @sSQL, @ParmDefinition, @retvalOUT=@retval OUTPUT;

SELECT @retval;

But if you don't, and can not modify the SP:

-- Assuming that your SP return 1 value
create table #temptable (ID int null)
insert into #temptable exec mysp 'Value1', 'Value2'
select * from #temptable

Not pretty, but works.

How to get index using LINQ?

An IEnumerable is not an ordered set.
Although most IEnumerables are ordered, some (such as Dictionary or HashSet) are not.

Therefore, LINQ does not have an IndexOf method.

However, you can write one yourself:

///<summary>Finds the index of the first item matching an expression in an enumerable.</summary>
///<param name="items">The enumerable to search.</param>
///<param name="predicate">The expression to test the items against.</param>
///<returns>The index of the first matching item, or -1 if no items match.</returns>
public static int FindIndex<T>(this IEnumerable<T> items, Func<T, bool> predicate) {
    if (items == null) throw new ArgumentNullException("items");
    if (predicate == null) throw new ArgumentNullException("predicate");

    int retVal = 0;
    foreach (var item in items) {
        if (predicate(item)) return retVal;
        retVal++;
    }
    return -1;
}
///<summary>Finds the index of the first occurrence of an item in an enumerable.</summary>
///<param name="items">The enumerable to search.</param>
///<param name="item">The item to find.</param>
///<returns>The index of the first matching item, or -1 if the item was not found.</returns>
public static int IndexOf<T>(this IEnumerable<T> items, T item) { return items.FindIndex(i => EqualityComparer<T>.Default.Equals(item, i)); }

Place API key in Headers or URL

It is better to use API Key in header, not in URL.

URLs are saved in browser's history if it is tried from browser. It is very rare scenario. But problem comes when the backend server logs all URLs. It might expose the API key.

In two ways, you can use API Key in header

Basic Authorization:

Example from stripe:

curl https://api.stripe.com/v1/charges -u sk_test_BQokikJOvBiI2HlWgH4olfQ2:

curl uses the -u flag to pass basic auth credentials (adding a colon after your API key will prevent it from asking you for a password).

Custom Header

curl -H "X-API-KEY: 6fa741de1bdd1d91830ba" https://api.mydomain.com/v1/users

bootstrap responsive table content wrapping

The UberNeo response is Ok and i like it because you do not have to modify anything else except the TD. The only point is that you also have to add "white-space:normal" to the style in order to maintain the responsive characteristics of the table, if not, at certain resolutions the wrap is not made and the scroll of the table does not appear.

style="word-wrap: break-word;min-width: 160px;max-width: 160px;white-space:normal;"

Error: Cannot pull with rebase: You have unstaged changes

If you want to keep your working changes while performing a rebase, you can use --autostash. From the documentation:

Before starting rebase, stash local modifications away (see git-stash[1]) if needed, and apply the stash when done.

For example:

git pull --rebase --autostash

GZIPInputStream reading line by line

You can use the following method in a util class, and use it whenever necessary...

public static List<String> readLinesFromGZ(String filePath) {
    List<String> lines = new ArrayList<>();
    File file = new File(filePath);

    try (GZIPInputStream gzip = new GZIPInputStream(new FileInputStream(file));
            BufferedReader br = new BufferedReader(new InputStreamReader(gzip));) {
        String line = null;
        while ((line = br.readLine()) != null) {
            lines.add(line);
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
    return lines;
}

"Prevent saving changes that require the table to be re-created" negative effects

Tools --> Options --> Designers node --> Uncheck " Prevent saving changes that require table recreation ".

Time stamp in the C programming language

/*
 Returns the current time.
*/

char *time_stamp(){

char *timestamp = (char *)malloc(sizeof(char) * 16);
time_t ltime;
ltime=time(NULL);
struct tm *tm;
tm=localtime(&ltime);

sprintf(timestamp,"%04d%02d%02d%02d%02d%02d", tm->tm_year+1900, tm->tm_mon, 
    tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
return timestamp;
}


int main(){

printf(" Timestamp: %s\n",time_stamp());
return 0;

}

Output: Timestamp: 20110912130940 // 2011 Sep 12 13:09:40

How to make fixed header table inside scrollable div?

Using position: sticky on th will do the trick.

Note: if you use position: sticky on thead or tr, it won't work.

https://jsfiddle.net/hrg3tmxj/

Is it safe to store a JWT in localStorage with ReactJS?

Localstorage is designed to be accessible by javascript, so it doesn't provide any XSS protection. As mentioned in other answers, there is a bunch of possible ways to do an XSS attack, from which localstorage is not protected by default.

However, cookies have security flags which protect from XSS and CSRF attacks. HttpOnly flag prevents client side javascript from accessing the cookie, Secure flag only allows the browser to transfer the cookie through ssl, and SameSite flag ensures that the cookie is sent only to the origin. Although I just checked and SameSite is currently supported only in Opera and Chrome, so to protect from CSRF it's better to use other strategies. For example, sending an encrypted token in another cookie with some public user data.

So cookies are a more secure choice for storing authentication data.

SQL Server IF EXISTS THEN 1 ELSE 2

Its best practice to have TOP 1 1 always.

What if I use SELECT 1 -> If condition matches more than one record then your query will fetch all the columns records and returns 1.

What if I use SELECT TOP 1 1 -> If condition matches more than one record also, it will just fetch the existence of any row (with a self 1-valued column) and returns 1.

IF EXISTS (SELECT TOP 1 1 FROM tblGLUserAccess WHERE GLUserName ='xxxxxxxx') 
BEGIN
   SELECT 1 
END
ELSE
BEGIN
    SELECT 2
END

How to retrieve value from elements in array using jQuery?

jQuery collections have a built in iterator with .each:

$("input[name^='card']").each(function () {
   console.log($(this).val());
}

How to use ConcurrentLinkedQueue?

This is probably what you're looking for in terms of thread safety & "prettyness" when trying to consume everything in the queue:

for (YourObject obj = queue.poll(); obj != null; obj = queue.poll()) {
}

This will guarantee that you quit when the queue is empty, and that you continue to pop objects off of it as long as it's not empty.

java.lang.RuntimeException: Unable to start activity ComponentInfo

Dear You have used two Intent launcher in your Manifest. Make only one Activity as launcher: Your manifest activity is :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.th.mybook"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk android:minSdkVersion="8" />
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name=".MainTabPanel"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="MyBookActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.ALTERNATIVE" />
            </intent-filter>
        </activity>
    </application>
</manifest>

now write code will be ( i have made your 'MyActivityBook' your default activity launcher. Copy and paste it on your manifest.

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="org.th.mybook"
        android:versionCode="1"
        android:versionName="1.0" >
        <uses-sdk android:minSdkVersion="8" />
        <application
            android:icon="@drawable/ic_launcher"
            android:label="@string/app_name" >
            <activity
                android:name=".MainTabPanel"
                android:label="@string/app_name" >

            </activity>
            <activity
                android:name="MyBookActivity"
                android:label="@string/app_name" >
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
        </application>
    </manifest>

and Second error may be if you copy paste old code then please update com.example.packagename.FILE_NAME

hope this will work !

How do you parse and process HTML/XML in PHP?

I've created a library called HTML5DOMDocument that is freely available at https://github.com/ivopetkov/html5-dom-document-php

It supports query selectors too that I think will be extremely helpful in your case. Here is some example code:

$dom = new IvoPetkov\HTML5DOMDocument();
$dom->loadHTML('<!DOCTYPE html><html><body><h1>Hello</h1><div class="content">This is some text</div></body></html>');
echo $dom->querySelector('h1')->innerHTML;

403 Forbidden You don't have permission to access /folder-name/ on this server

under etc/apache2/apache2.conf, you can find one or more blocks that describe the server directories and permissions

As an example, this is the default configuration

<Directory /var/www/>
   Options Indexes FollowSymLinks
   AllowOverride None
   Require all granted
</Directory>

you can replicate this but change the directory path /var/www/ with the new directory.

Finally, you need to restart the apache server, you can do that from a terminal with the command: sudo service apache2 restart

jquery - disable click

You can use unbind method to remove handler that has been attached...

if (current = 1){ 
   $('li:eq(2)').unbind('click');
}

You can check what can unbind do ? Unbind manual

Batch file to perform start, run, %TEMP% and delete all

Just use

del /f /q C:\Users\%username%\AppData\Local\temp

And it will work.

Note: It will delete the whole folder however, Windows will remake it as it needs.

Convert integer to hexadecimal and back again

// Store integer 182
int intValue = 182;
// Convert integer 182 as a hex in a string variable
string hexValue = intValue.ToString("X");
// Convert the hex string back to the number
int intAgain = int.Parse(hexValue, System.Globalization.NumberStyles.HexNumber);

from http://www.geekpedia.com/KB8_How-do-I-convert-from-decimal-to-hex-and-hex-to-decimal.html

Get the value in an input text box

Pure JS

txt_name.value

_x000D_
_x000D_
txt_name.onkeyup = e=> alert(txt_name.value);
_x000D_
<input type="text" id="txt_name" />
_x000D_
_x000D_
_x000D_

Where does application data file actually stored on android device?

You can get if from your document_cache folder, subfolder (mine is 1946507). Once there, rename the "content" by adding .pdf to the end of the file, save, and open with any pdf reader.

Looping through array and removing items, without breaking for loop

Here is another example for the proper use of splice. This example is about to remove 'attribute' from 'array'.

for (var i = array.length; i--;) {
    if (array[i] === 'attribute') {
        array.splice(i, 1);
    }
}

PHP code to remove everything but numbers

You would need to enclose the pattern in a delimiter - typically a slash (/) is used. Try this:

echo preg_replace("/[^0-9]/","",'604-619-5135');

How can I change the image of an ImageView?

if (android.os.Build.VERSION.SDK_INT >= 21) {
            storeViewHolder.storeNameTextView.setImageDrawable(context.getResources().getDrawable(array[position], context.getTheme()));
} else {
            storeViewHolder.storeNameTextView.setImageDrawable(context.getResources().getDrawable(array[position]));
}

C fopen vs open

open() will be called at the end of each of the fopen() family functions. open() is a system call and fopen() are provided by libraries as a wrapper functions for user easy of use

Remove the string on the beginning of an URL

Try the following

var original = 'www.test.com';
var stripped = original.substring(4);

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

This is fast and works for small and (arbitrary) large ints:

def Dump(n): 
  s = '%x' % n
  if len(s) & 1:
    s = '0' + s
  return s.decode('hex')
print repr(Dump(1245427))  #: '\x13\x00\xf3'

What happened to console.log in IE8?

Make your own console in html .... ;-) This can be imprved but you can start with :

if (typeof console == "undefined" || typeof console.log === "undefined") {
    var oDiv=document.createElement("div");
    var attr = document.createAttribute('id'); attr.value = 'html-console';
    oDiv.setAttributeNode(attr);


    var style= document.createAttribute('style');
    style.value = "overflow: auto; color: red; position: fixed; bottom:0; background-color: black; height: 200px; width: 100%; filter: alpha(opacity=80);";
    oDiv.setAttributeNode(style);

    var t = document.createElement("h3");
    var tcontent = document.createTextNode('console');
    t.appendChild(tcontent);
    oDiv.appendChild(t);

    document.body.appendChild(oDiv);
    var htmlConsole = document.getElementById('html-console');
    window.console = {
        log: function(message) {
            var p = document.createElement("p");
            var content = document.createTextNode(message.toString());
            p.appendChild(content);
            htmlConsole.appendChild(p);
        }
    };
}

What is cURL in PHP?

cURL

  • cURL is a way you can hit a URL from your code to get a HTML response from it.
  • It's used for command line cURL from the PHP language.
  • cURL is a library that lets you make HTTP requests in PHP.

PHP supports libcurl, a library created by Daniel Stenberg, that allows you to connect and communicate to many different types of servers with many different types of protocols. libcurl currently supports the http, https, ftp, gopher, telnet, dict, file, and ldap protocols. libcurl also supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading (this can also be done with PHP's ftp extension), HTTP form based upload, proxies, cookies, and user+password authentication.

Once you've compiled PHP with cURL support, you can begin using the cURL functions. The basic idea behind the cURL functions is that you initialize a cURL session using the curl_init(), then you can set all your options for the transfer via the curl_setopt(), then you can execute the session with the curl_exec() and then you finish off your session using the curl_close().

Sample Code

// error reporting
error_reporting(E_ALL);
ini_set("display_errors", 1);

//setting url
$url = 'http://example.com/api';

//data
$data = array("message" => "Hello World!!!");

try {
    $ch = curl_init($url);
    $data_string = json_encode($data);

    if (FALSE === $ch)
        throw new Exception('failed to initialize');

        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
        curl_setopt($ch, CURLOPT_HTTPHEADER, array( 'Content-Type: application/json', 'Content-Length: ' . strlen($data_string)));
        curl_setopt($ch, CURLOPT_TIMEOUT, 5);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);

        $output = curl_exec($ch);

    if (FALSE === $output)
        throw new Exception(curl_error($ch), curl_errno($ch));

    // ...process $output now
} catch(Exception $e) {

    trigger_error(sprintf(
        'Curl failed with error #%d: %s',
        $e->getCode(), $e->getMessage()),
        E_USER_ERROR);
}

For more information, please check -

How should I deal with "package 'xxx' is not available (for R version x.y.z)" warning?

In the latest R (3.2.3) there is a bug, preventing it some times from finding correct package. The workaround is to set repository manually:

install.packages("lubridate", dependencies=TRUE, repos='http://cran.rstudio.com/')

Found solution in other question

How to get ID of clicked element with jQuery

You just need to remove the hash from the beginning:

$('a.pagerlink').click(function() { 
    var id = $(this).attr('id').substring(1);
    $container.cycle(id); 
    return false; 
}); 

Correct use for angular-translate in controllers

EDIT: Please see the answer from PascalPrecht (the author of angular-translate) for a better solution.


The asynchronous nature of the loading causes the problem. You see, with {{ pageTitle | translate }}, Angular will watch the expression; when the localization data is loaded, the value of the expression changes and the screen is updated.

So, you can do that yourself:

.controller('FirstPageCtrl', ['$scope', '$filter', function ($scope, $filter) {
    $scope.$watch(
        function() { return $filter('translate')('HELLO_WORLD'); },
        function(newval) { $scope.pageTitle = newval; }
    );
});

However, this will run the watched expression on every digest cycle. This is suboptimal and may or may not cause a visible performance degradation. Anyway it is what Angular does, so it cant be that bad...

How to represent a fix number of repeats in regular expression?

^\w{14}$ in Perl and any Perl-style regex.

If you want to learn more about regular expressions - or just need a handy reference - the Wikipedia Entry on Regular Expressions is actually pretty good.

How to add a progress bar to a shell script?

This is a psychedelic progressbar for bash scripting by nExace. It can be called from command line as './progressbar x y' where 'x' is a time in seconds and 'y' is a message associated with that portion of the progress.

The inner progressbar() function itself is good standalone as well if you want other portions of your script to control the progressbar. For instance, sending 'progressbar 10 "Creating directory tree";' will display:

[#######                                     ] (10%) Creating directory tree

Of course it will be nicely psychedelic though...

#!/bin/bash

if [ "$#" -eq 0 ]; then echo "x is \"time in seconds\" and z is \"message\""; echo "Usage: progressbar x z"; exit; fi
progressbar() {
        local loca=$1; local loca2=$2;
        declare -a bgcolors; declare -a fgcolors;
        for i in {40..46} {100..106}; do
                bgcolors+=("$i")
        done
        for i in {30..36} {90..96}; do
                fgcolors+=("$i")
        done
        local u=$(( 50 - loca ));
        local y; local t;
        local z; z=$(printf '%*s' "$u");
        local w=$(( loca * 2 ));
        local bouncer=".oO°Oo.";
        for ((i=0;i<loca;i++)); do
                t="${bouncer:((i%${#bouncer})):1}"
                bgcolor="\\E[${bgcolors[RANDOM % 14]}m \\033[m"
                y+="$bgcolor";
        done
        fgcolor="\\E[${fgcolors[RANDOM % 14]}m"
        echo -ne " $fgcolor$t$y$z$fgcolor$t \\E[96m(\\E[36m$w%\\E[96m)\\E[92m $fgcolor$loca2\\033[m\r"
};
timeprogress() {
        local loca="$1"; local loca2="$2";
        loca=$(bc -l <<< scale=2\;"$loca/50")
        for i in {1..50}; do
                progressbar "$i" "$loca2";
                sleep "$loca";
        done
        printf "\n"
};
timeprogress "$1" "$2"

Invalid use side-effecting operator Insert within a function

You can't use a function to insert data into a base table. Functions return data. This is listed as the very first limitation in the documentation:

User-defined functions cannot be used to perform actions that modify the database state.

"Modify the database state" includes changing any data in the database (though a table variable is an obvious exception the OP wouldn't have cared about 3 years ago - this table variable only lives for the duration of the function call and does not affect the underlying tables in any way).

You should be using a stored procedure, not a function.

What is a mutex?

In C#, the common mutex used is the Monitor. The type is 'System.Threading.Monitor'. It may also be used implicitly via the 'lock(Object)' statement. One example of its use is when constructing a Singleton class.

private static readonly Object instanceLock = new Object();
private static MySingleton instance;
public static MySingleton Instance
{
    lock(instanceLock)
    {
        if(instance == null)
        {
            instance = new MySingleton();
        }
        return instance;
    }
}

The lock statement using the private lock object creates a critical section. Requiring each thread to wait until the previous is finished. The first thread will enter the section and initialize the instance. The second thread will wait, get into the section, and get the initialized instance.

Any sort of synchronization of a static member may use the lock statement similarly.

Email & Phone Validation in Swift

Swift 3.0 to 5.0 Updated Solution:

//MARK:- Validation Extension -

extension String {

    //To check text field or String is blank or not
    var isBlank: Bool {
        get {
            let trimmed = trimmingCharacters(in: CharacterSet.whitespaces)
            return trimmed.isEmpty
        }
    }

    //Validate Email

    var isEmail: Bool {
        do {
            let regex = try NSRegularExpression(pattern: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}", options: .caseInsensitive)
            return regex.firstMatch(in: self, options: NSRegularExpression.MatchingOptions(rawValue: 0), range: NSMakeRange(0, self.count)) != nil
        } catch {
            return false
        }
    }

    var isAlphanumeric: Bool {
        return !isEmpty && range(of: "[^a-zA-Z0-9]", options: .regularExpression) == nil
    }

    //validate Password
    var isValidPassword: Bool {
        do {
            let regex = try NSRegularExpression(pattern: "^[a-zA-Z_0-9\\-_,;.:#+*?=!§$%&/()@]+$", options: .caseInsensitive)
            if(regex.firstMatch(in: self, options: NSRegularExpression.MatchingOptions(rawValue: 0), range: NSMakeRange(0, self.characters.count)) != nil){

                if(self.characters.count>=6 && self.count<=20){
                    return true
                }else{
                    return false
                }
            }else{
                return false
            }
        } catch {
            return false
        }
    }
}

use of Email Validation:

if(txtEmail.isEmail){
}

Swift 2.0 Solution

Paste these line anywhere in code.(or in your Constant file)

extension String {

    //To check text field or String is blank or not
    var isBlank: Bool {
        get {
            let trimmed = stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
            return trimmed.isEmpty
        }
    }

    //Validate Email
    var isEmail: Bool {
        do {
            let regex = try NSRegularExpression(pattern: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}", options: .CaseInsensitive)
            return regex.firstMatchInString(self, options: NSMatchingOptions(rawValue: 0), range: NSMakeRange(0, self.count)) != nil
        } catch {
            return false
        }
    }

    //validate PhoneNumber
    var isPhoneNumber: Bool {

        let charcter  = NSCharacterSet(charactersInString: "+0123456789").invertedSet
        var filtered:NSString!
        let inputString:NSArray = self.componentsSeparatedByCharactersInSet(charcter)
        filtered = inputString.componentsJoinedByString("")
        return  self == filtered

    }
}

Open an image using URI in Android's default gallery image viewer

This thing might help if your working with android N and below

 File file=new File(Environment.getExternalStorageDirectory()+"/directoryname/"+filename);
        Uri path= FileProvider.getUriForFile(MainActivity.this,BuildConfig.APPLICATION_ID + ".provider",file);

        Intent intent=new Intent(Intent.ACTION_VIEW);
        intent.setDataAndType(path,"image/*");
        intent.setFlags(FLAG_GRANT_READ_URI_PERMISSION | FLAG_GRANT_WRITE_URI_PERMISSION); //must for reading data from directory

Difference between onStart() and onResume()

Short answer:

We can't live without onStart because that is the state when the activity becomes "visible" to the user, but the user cant "interact" with it yet may be cause it's overlapped with some other small dialog. This ability to interact with the user is the one that differentiates onStart and onResume. Think of it as a person behind a glass door. You can see the person but you can't interact (talk/listen/shake hands) with him. OnResume is like the door opener after which you can begin the interaction.

Additionally onRestart() is the least understood one. We can ask the question as to why not directly go to onStart() or onResume() after onStop() instead of onRestart(). It becomes easier to understand if we note that onRestart() is partially equivalent to onCreate() if the creation part is omitted. Basically both states lead to onStart() (i.e the Activity becomes visible). So both the states have to "prepare" the stuff to be displayed. OnCreate has the additional responsibility to "create" the stuff to be displayed

So their code structures might fit to something like:

onCreate()
{
     createNecessaryObjects();

     prepareObjectsForDisplay();
}


onRestart()
{
     prepareObjectsForDisplay();

}

The entire confusion is caused since Google chose non-intuitive names instead of something as follows:

onCreateAndPrepareToDisplay()   [instead of onCreate() ]
onPrepareToDisplay()            [instead of onRestart() ]
onVisible()                     [instead of onStart() ]
onBeginInteraction()            [instead of onResume() ]
onPauseInteraction()            [instead of onPause() ]
onInvisible()                   [instead of onStop]
onDestroy()                     [no change] 

The Activity Diagram might be interpreted as:

Android Activity Lifecycle

What's the difference between SCSS and Sass?

Sass (Syntactically Awesome StyleSheets) have two syntaxes:

  • a newer: SCSS (Sassy CSS)
  • and an older, original: indent syntax, which is the original Sass and is also called Sass.

So they are both part of Sass preprocessor with two different possible syntaxes.

The most important difference between SCSS and original Sass:

SCSS:

  • Syntax is similar to CSS (so much that every regular valid CSS3 is also valid SCSS, but the relationship in the other direction obviously does not happen)

  • Uses braces {}

  • Uses semi-colons ;
  • Assignment sign is :
  • To create a mixin it uses the @mixin directive
  • To use mixin it precedes it with the @include directive
  • Files have the .scss extension.

Original Sass:

  • Syntax is similar to Ruby
  • No braces
  • No strict indentation
  • No semi-colons
  • Assignment sign is = instead of :
  • To create a mixin it uses the = sign
  • To use mixin it precedes it with the + sign
  • Files have the .sass extension.

Some prefer Sass, the original syntax - while others prefer SCSS. Either way, but it is worth noting that Sass’s indented syntax has not been and will never be deprecated.

Conversions with sass-convert:

# Convert Sass to SCSS
$ sass-convert style.sass style.scss

# Convert SCSS to Sass
$ sass-convert style.scss style.sass

The Sass and SCSS documentation

Error on renaming database in SQL Server 2008 R2

Try to close all connections to your database first:

use master
ALTER DATABASE BOSEVIKRAM SET SINGLE_USER WITH ROLLBACK IMMEDIATE 

ALTER DATABASE BOSEVIKRAM MODIFY NAME = [BOSEVIKRAM_Deleted]

ALTER DATABASE BOSEVIKRAM_Deleted SET MULTI_USER

Taken from here

What is the difference between instanceof and Class.isAssignableFrom(...)?

Consider following situation. Suppose you want to check whether type A is a super class of the type of obj, you can go either

... A.class.isAssignableFrom(obj.getClass()) ...

OR

... obj instanceof A ...

But the isAssignableFrom solution requires that the type of obj be visible here. If this is not the case (e.g., the type of obj might be of a private inner class), this option is out. However, the instanceof solution would always work.

Javascript change color of text and background to input value

Things seems a little confused in the code in your question, so I am going to give you an example of what I think you are try to do.

First considerations are about mixing HTML, Javascript and CSS:

Why is using onClick() in HTML a bad practice?

Unobtrusive Javascript

Inline Styles vs Classes

I will be removing inline content and splitting these into their appropriate files.

Next, I am going to go with the "click" event and displose of the "change" event, as it is not clear that you want or need both.

Your function changeBackground sets both the backround color and the text color to the same value (your text will not be seen), so I am caching the color value as we don't need to look it up in the DOM twice.

CSS

#TheForm {
    margin-left: 396px;
}
#submitColor {
    margin-left: 48px;
    margin-top: 5px;
}

HTML

<form id="TheForm">
    <input id="color" type="text" />
    <br/>
    <input id="submitColor" value="Submit" type="button" />
</form>
<span id="coltext">This text should have the same color as you put in the text box</span>

Javascript

function changeBackground() {
    var color = document.getElementById("color").value; // cached

    // The working function for changing background color.
    document.bgColor = color;

    // The code I'd like to use for changing the text simultaneously - however it does not work.
    document.getElementById("coltext").style.color = color;
}

document.getElementById("submitColor").addEventListener("click", changeBackground, false);

On jsfiddle

Source: w3schools

Color Values

CSS colors are defined using a hexadecimal (hex) notation for the combination of Red, Green, and Blue color values (RGB). The lowest value that can be given to one of the light sources is 0 (hex 00). The highest value is 255 (hex FF).

Hex values are written as 3 double digit numbers, starting with a # sign.

Update: as pointed out by @Ian

Hex can be either 3 or 6 characters long

Source: W3C

Numerical color values

The format of an RGB value in hexadecimal notation is a ‘#’ immediately followed by either three or six hexadecimal characters. The three-digit RGB notation (#rgb) is converted into six-digit form (#rrggbb) by replicating digits, not by adding zeros. For example, #fb0 expands to #ffbb00. This ensures that white (#ffffff) can be specified with the short notation (#fff) and removes any dependencies on the color depth of the display.

Here is an alternative function that will check that your input is a valid CSS Hex Color, it will set the text color only or throw an alert if it is not valid.

For regex testing, I will use this pattern

/^#(?:[0-9a-f]{3}){1,2}$/i

but if you were regex matching and wanted to break the numbers into groups then you would require a different pattern

function changeBackground() {
    var color = document.getElementById("color").value.trim(),
        rxValidHex = /^#(?:[0-9a-f]{3}){1,2}$/i;

    if (rxValidHex.test(color)) {
        document.getElementById("coltext").style.color = color;
    } else {
        alert("Invalid CSS Hex Color");
    }
}

document.getElementById("submitColor").addEventListener("click", changeBackground, false);

On jsfiddle

Here is a further modification that will allow colours by name along with by hex.

function changeBackground() {
    var names = ["AliceBlue", "AntiqueWhite", "Aqua", "Aquamarine", "Azure", "Beige", "Bisque", "Black", "BlanchedAlmond", "Blue", "BlueViolet", "Brown", "BurlyWood", "CadetBlue", "Chartreuse", "Chocolate", "Coral", "CornflowerBlue", "Cornsilk", "Crimson", "Cyan", "DarkBlue", "DarkCyan", "DarkGoldenRod", "DarkGray", "DarkGrey", "DarkGreen", "DarkKhaki", "DarkMagenta", "DarkOliveGreen", "Darkorange", "DarkOrchid", "DarkRed", "DarkSalmon", "DarkSeaGreen", "DarkSlateBlue", "DarkSlateGray", "DarkSlateGrey", "DarkTurquoise", "DarkViolet", "DeepPink", "DeepSkyBlue", "DimGray", "DimGrey", "DodgerBlue", "FireBrick", "FloralWhite", "ForestGreen", "Fuchsia", "Gainsboro", "GhostWhite", "Gold", "GoldenRod", "Gray", "Grey", "Green", "GreenYellow", "HoneyDew", "HotPink", "IndianRed", "Indigo", "Ivory", "Khaki", "Lavender", "LavenderBlush", "LawnGreen", "LemonChiffon", "LightBlue", "LightCoral", "LightCyan", "LightGoldenRodYellow", "LightGray", "LightGrey", "LightGreen", "LightPink", "LightSalmon", "LightSeaGreen", "LightSkyBlue", "LightSlateGray", "LightSlateGrey", "LightSteelBlue", "LightYellow", "Lime", "LimeGreen", "Linen", "Magenta", "Maroon", "MediumAquaMarine", "MediumBlue", "MediumOrchid", "MediumPurple", "MediumSeaGreen", "MediumSlateBlue", "MediumSpringGreen", "MediumTurquoise", "MediumVioletRed", "MidnightBlue", "MintCream", "MistyRose", "Moccasin", "NavajoWhite", "Navy", "OldLace", "Olive", "OliveDrab", "Orange", "OrangeRed", "Orchid", "PaleGoldenRod", "PaleGreen", "PaleTurquoise", "PaleVioletRed", "PapayaWhip", "PeachPuff", "Peru", "Pink", "Plum", "PowderBlue", "Purple", "Red", "RosyBrown", "RoyalBlue", "SaddleBrown", "Salmon", "SandyBrown", "SeaGreen", "SeaShell", "Sienna", "Silver", "SkyBlue", "SlateBlue", "SlateGray", "SlateGrey", "Snow", "SpringGreen", "SteelBlue", "Tan", "Teal", "Thistle", "Tomato", "Turquoise", "Violet", "Wheat", "White", "WhiteSmoke", "Yellow", "YellowGreen"],
        color = document.getElementById("color").value.trim(),
        rxValidHex = /^#(?:[0-9a-f]{3}){1,2}$/i,
        formattedName = color.charAt(0).toUpperCase() + color.slice(1).toLowerCase();

    if (names.indexOf(formattedName) !== -1 || rxValidHex.test(color)) {
        document.getElementById("coltext").style.color = color;
    } else {
        alert("Invalid CSS Color");
    }
}

document.getElementById("submitColor").addEventListener("click", changeBackground, false);

On jsfiddle

Differences Between vbLf, vbCrLf & vbCr Constants

The three constants have similar functions nowadays, but different historical origins, and very occasionally you may be required to use one or the other.

You need to think back to the days of old manual typewriters to get the origins of this. There are two distinct actions needed to start a new line of text:

  1. move the typing head back to the left. In practice in a typewriter this is done by moving the roll which carries the paper (the "carriage") all the way back to the right -- the typing head is fixed. This is a carriage return.
  2. move the paper up by the width of one line. This is a line feed.

In computers, these two actions are represented by two different characters - carriage return is CR, ASCII character 13, vbCr; line feed is LF, ASCII character 10, vbLf. In the old days of teletypes and line printers, the printer needed to be sent these two characters -- traditionally in the sequence CRLF -- to start a new line, and so the CRLF combination -- vbCrLf -- became a traditional line ending sequence, in some computing environments.

The problem was, of course, that it made just as much sense to only use one character to mark the line ending, and have the terminal or printer perform both the carriage return and line feed actions automatically. And so before you knew it, we had 3 different valid line endings: LF alone (used in Unix and Macintoshes), CR alone (apparently used in older Mac OSes) and the CRLF combination (used in DOS, and hence in Windows). This in turn led to the complications of DOS / Windows programs having the option of opening files in text mode, where any CRLF pair read from the file was converted to a single CR (and vice versa when writing).

So - to cut a (much too) long story short - there are historical reasons for the existence of the three separate line separators, which are now often irrelevant: and perhaps the best course of action in .NET is to use Environment.NewLine which means someone else has decided for you which to use, and future portability issues should be reduced.

Assign output to variable in Bash

Same with something more complex...getting the ec2 instance region from within the instance.

INSTANCE_REGION=$(curl -s 'http://169.254.169.254/latest/dynamic/instance-identity/document' | python -c "import sys, json; print json.load(sys.stdin)['region']")

echo $INSTANCE_REGION

Angular2 RC6: '<component> is not a known element'

I was facing this issue on Angular 7 and the problem was after creating the module, I did not perform ng build. So I performed -

  • ng build
  • ng serve

and it worked.

Concatenate multiple result rows of one column into one, group by another column

Simpler with the aggregate function string_agg() (Postgres 9.0 or later):

SELECT movie, string_agg(actor, ', ') AS actor_list
FROM   tbl
GROUP  BY 1;

The 1 in GROUP BY 1 is a positional reference and a shortcut for GROUP BY movie in this case.

string_agg() expects data type text as input. Other types need to be cast explicitly (actor::text) - unless an implicit cast to text is defined - which is the case for all other character types (varchar, character, "char"), and some other types.

As isapir commented, you can add an ORDER BY clause in the aggregate call to get a sorted list - should you need that. Like:

SELECT movie, string_agg(actor, ', ' ORDER BY actor) AS actor_list
FROM   tbl
GROUP  BY 1;

But it's typically faster to sort rows in a subquery. See:

Is there a pretty print for PHP?

This is what I use to print my arrays:

<pre>
    <?php
        print_r($your_array);
    ?>
</pre>

The magic comes with the pre tag.

Where to put Gradle configuration (i.e. credentials) that should not be committed?

You could also supply variables on the command line with -PmavenUser=user -PmavenPassword=password.

This might be useful you can't use a gradle.properties file for some reason. E.g. on a build server we're using Gradle with the -g option so that each build plan has it's own GRADLE_HOME.

Contain an image within a div?

#container img{
 height:100%;
 width:100%;   
}

Renaming column names of a DataFrame in Spark Scala

For those of you interested in PySpark version (actually it's same in Scala - see comment below) :

    merchants_df_renamed = merchants_df.toDF(
        'merchant_id', 'category', 'subcategory', 'merchant')

    merchants_df_renamed.printSchema()

Result:

root
|-- merchant_id: integer (nullable = true)
|-- category: string (nullable = true)
|-- subcategory: string (nullable = true)
|-- merchant: string (nullable = true)

PowerShell to remove text from a string

This should do what you want:

C:\PS> if ('=keep this,' -match '=([^,]*)') { $matches[1] }
keep this

invalid use of non-static data member

In C++, unlike (say) Java, an instance of a nested class doesn't intrinsically belong to any instance of the enclosing class. So bar::getA doesn't have any specific instance of foo whose a it can be returning. I'm guessing that what you want is something like:

    class bar {
      private:
        foo * const owner;
      public:
        bar(foo & owner) : owner(&owner) { }
        int getA() {return owner->a;}
    };

But even for this you may have to make some changes, because in versions of C++ before C++11, unlike (again, say) Java, a nested class has no special access to its enclosing class, so it can't see the protected member a. This will depend on your compiler version. (Hat-tip to Ken Wayne VanderLinde for pointing out that C++11 has changed this.)

How can I exclude multiple folders using Get-ChildItem -exclude?

My KISS approach to skip some folders is chaining Get-ChildItem calls. This excludes root level folders but not deeper level folders if that is what you want.

Get-ChildItem -Exclude folder1,folder2 | Get-ChildItem -Recurse | ...
  • Start excluding folders you don't want
  • Then do the recursive search with non desired folders excluded.

What I like from this approach is that it is simple and easy to remember. If you don't want to mix folders and files in the first search a filter would be needed.

AngularJS UI Router - change url without reloading state

Try something like this

$state.go($state.$current.name, {... $state.params, 'key': newValue}, {notify: false})

How to initialize a vector with fixed length in R

Just for the sake of completeness you can just take the wanted data type and add brackets with the number of elements like so:

x <- character(10)

How to iterate over the files of a certain directory, in Java?

I guess there are so many ways to make what you want. Here's a way that I use. With the commons.io library you can iterate over the files in a directory. You must use the FileUtils.iterateFiles method and you can process each file.

You can find the information here: http://commons.apache.org/proper/commons-io/download_io.cgi

Here's an example:

Iterator it = FileUtils.iterateFiles(new File("C:/"), null, false);
        while(it.hasNext()){
            System.out.println(((File) it.next()).getName());
        }

You can change null and put a list of extentions if you wanna filter. Example: {".xml",".java"}

Entity Framework Timeouts

If you are using Entity Framework like me, you should define Time out on Startup class as follows:

 services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"), o => o.CommandTimeout(180)));

Get table column names in MySQL?

The following SQL statements are nearly equivalent:

SELECT COLUMN_NAME
  FROM INFORMATION_SCHEMA.COLUMNS
 WHERE table_name = 'tbl_name'
  [AND table_schema = 'db_name']
  [AND column_name LIKE 'wild']

SHOW COLUMNS
FROM tbl_name
[FROM db_name]
[LIKE 'wild']

Reference: INFORMATION_SCHEMA COLUMNS

How to retrieve the dimensions of a view?

You are trying to get width and height of an elements, that weren't drawn yet.

If you use debug and stop at some point, you'll see, that your device screen is still empty, that's because your elements weren't drawn yet, so you can't get width and height of something, that doesn't yet exist.

And, I might be wrong, but setWidth() is not always respected, Layout lays out it's children and decides how to measure them (calling child.measure()), so If you set setWidth(), you are not guaranteed to get this width after element will be drawn.

What you need, is to use getMeasuredWidth() (the most recent measure of your View) somewhere after the view was actually drawn.

Look into Activity lifecycle for finding the best moment.

http://developer.android.com/reference/android/app/Activity.html#ActivityLifecycle

I believe a good practice is to use OnGlobalLayoutListener like this:

yourView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            if (!mMeasured) {
                // Here your view is already layed out and measured for the first time
                mMeasured = true; // Some optional flag to mark, that we already got the sizes
            }
        }
    });

You can place this code directly in onCreate(), and it will be invoked when views will be laid out.

Using Python's ftplib to get a directory listing, portably

That helped me with my code.

When I tried feltering only a type of files and show them on screen by adding a condition that tests on each line.

Like this

elif command == 'ls':
    print("directory of ", ftp.pwd())
    data = []
    ftp.dir(data.append)

    for line in data:
        x = line.split(".")
        formats=["gz", "zip", "rar", "tar", "bz2", "xz"]
        if x[-1] in formats:
            print ("-", line)

How to convert JTextField to String and String to JTextField?

The JTextField offers a getText() and a setText() method - those are for getting and setting the content of the text field.

"No such file or directory" but it exists

Added here for future reference (for users who might fall into the same case): This error happens when working on Windows (which introduces extra characters because of different line separator than Linux system) and trying to run this script (with extra characters inserted) in Linux. The error message is misleading.

In Windows, the line separator is CRLF (\r\n) whereas in linux it is LF (\n). This can be usually be chosen in text editor.

In my case, this happened due to working on Windows and uploading to Unix server for execution.

SVN Commit specific files

try this script..

#!/bin/bash
NULL="_"
for f in `svn st|grep -v ^\?|sed s/.\ *//`; 
     do LIST="${LIST} $f $NULL on"; 
done
dialog --checklist "Select files to commit" 30 60 30 $LIST 2>/tmp/svnlist.txt
svn ci `cat /tmp/svnlist.txt|sed 's/"//g'`

Where are my postgres *.conf files?

If you followed the white paper put out by Amazon for installing Postgresql on AWS, which included creating a /data/ directory on a filesystem mounted on a separate EBS volume, then your postgresql.conf file is in /data/

From which I conclude the file is created during initialisation of the data directory, and resides in the root of the data dir. For a default install this appears to be /var/lib/pgsql/data, but not if you moved the data dir

What is a predicate in c#?

Predicate<T> is a functional construct providing a convenient way of basically testing if something is true of a given T object.

For example suppose I have a class:

class Person {
    public string Name { get; set; }
    public int Age { get; set; }
}

Now let's say I have a List<Person> people and I want to know if there's anyone named Oscar in the list.

Without using a Predicate<Person> (or Linq, or any of that fancy stuff), I could always accomplish this by doing the following:

Person oscar = null;
foreach (Person person in people) {
    if (person.Name == "Oscar") {
        oscar = person;
        break;
    }
}

if (oscar != null) {
    // Oscar exists!
}

This is fine, but then let's say I want to check if there's a person named "Ruth"? Or a person whose age is 17?

Using a Predicate<Person>, I can find these things using a LOT less code:

Predicate<Person> oscarFinder = (Person p) => { return p.Name == "Oscar"; };
Predicate<Person> ruthFinder = (Person p) => { return p.Name == "Ruth"; };
Predicate<Person> seventeenYearOldFinder = (Person p) => { return p.Age == 17; };

Person oscar = people.Find(oscarFinder);
Person ruth = people.Find(ruthFinder);
Person seventeenYearOld = people.Find(seventeenYearOldFinder);

Notice I said a lot less code, not a lot faster. A common misconception developers have is that if something takes one line, it must perform better than something that takes ten lines. But behind the scenes, the Find method, which takes a Predicate<T>, is just enumerating after all. The same is true for a lot of Linq's functionality.

So let's take a look at the specific code in your question:

Predicate<int> pre = delegate(int a){ return a % 2 == 0; };

Here we have a Predicate<int> pre that takes an int a and returns a % 2 == 0. This is essentially testing for an even number. What that means is:

pre(1) == false;
pre(2) == true;

And so on. This also means, if you have a List<int> ints and you want to find the first even number, you can just do this:

int firstEven = ints.Find(pre);

Of course, as with any other type that you can use in code, it's a good idea to give your variables descriptive names; so I would advise changing the above pre to something like evenFinder or isEven -- something along those lines. Then the above code is a lot clearer:

int firstEven = ints.Find(evenFinder);

AES Encryption for an NSString on the iPhone

I have put together a collection of categories for NSData and NSString which uses solutions found on Jeff LaMarche's blog and some hints by Quinn Taylor here on Stack Overflow.

It uses categories to extend NSData to provide AES256 encryption and also offers an extension of NSString to BASE64-encode encrypted data safely to strings.

Here's an example to show the usage for encrypting strings:

NSString *plainString = @"This string will be encrypted";
NSString *key = @"YourEncryptionKey"; // should be provided by a user

NSLog( @"Original String: %@", plainString );

NSString *encryptedString = [plainString AES256EncryptWithKey:key];
NSLog( @"Encrypted String: %@", encryptedString );

NSLog( @"Decrypted String: %@", [encryptedString AES256DecryptWithKey:key] );

Get the full source code here:

https://gist.github.com/838614

Thanks for all the helpful hints!

-- Michael

The character encoding of the plain text document was not declared - mootool script

In your HTML it is a good pratice to provide the encoding like using the following meta like this for example:

<meta http-equiv="content-type" content="text/html; charset=utf-8" />

But your warning that you see may be trigged by one of multiple files. it might not be your HTML document. It might be something in a javascript file or css file. if you page is made of up multiples php files included together it may be only 1 of those files.

I dont think this error has anything to do with mootools. you see this message in your firefox console window. not mootools script.

maybe you simply need to re-save your html pages using a code editor that lets you specify the correct character encoding.

How can I convert ticks to a date format?

A DateTime object can be constructed with a specific value of ticks. Once you have determined the ticks value, you can do the following:

DateTime myDate = new DateTime(numberOfTicks);
String test = myDate.ToString("MMMM dd, yyyy");

How to make sql-mode="NO_ENGINE_SUBSTITUTION" permanent in MySQL my.cnf

If you're using mariadb, you have to modify the mariadb.cnf file located in /etc/mysql/conf.d/.

I supposed the stuff is the same for any other my-sql based solutions.

Parsing Json rest api response in C#

Create a C# class that maps to your Json and use Newsoft JsonConvert to Deserialise it.

For example:

public Class MyResponse
{
    public Meta Meta { get; set; }
    public Response Response { get; set; }
}

How to integrate Dart into a Rails app

If you run pub build --mode=debug the build directory contains the application without symlinks. The Dart code should be retained when --mode=debug is used.

Here is some discussion going on about this topic too Dart and it's place in Rails Assets Pipeline

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

Using JDK 1.6 or later

It has been pointed out by Justin in the comments below that keytool alone is capable of doing this using the following command (although only in JDK 1.6 and later):

keytool -importkeystore -srckeystore mypfxfile.pfx -srcstoretype pkcs12 
-destkeystore clientcert.jks -deststoretype JKS

Using JDK 1.5 or below

OpenSSL can do it all. This answer on JGuru is the best method that I've found so far.

Firstly make sure that you have OpenSSL installed. Many operating systems already have it installed as I found with Mac OS X.

The following two commands convert the pfx file to a format that can be opened as a Java PKCS12 key store:

openssl pkcs12 -in mypfxfile.pfx -out mypemfile.pem
openssl pkcs12 -export -in mypemfile.pem -out mykeystore.p12 -name "MyCert"

NOTE that the name provided in the second command is the alias of your key in the new key store.

You can verify the contents of the key store using the Java keytool utility with the following command:

keytool -v -list -keystore mykeystore.p12 -storetype pkcs12

Finally if you need to you can convert this to a JKS key store by importing the key store created above into a new key store:

keytool -importkeystore -srckeystore mykeystore.p12 -destkeystore clientcert.jks -srcstoretype pkcs12 -deststoretype JKS

Getting an option text/value with JavaScript

var option_user_selection = document.getElementById("maincourse").options[document.getElementById("maincourse").selectedIndex ].text

How can I create objects while adding them into a vector?

// create a vector of unknown players.
std::vector<player> players;

// resize said vector to only contain 6 players.
players.resize(6);

Values are always initialized, so a vector of 6 players is a vector of 6 valid player objects.

As for the second part, you need to use pointers. Instantiating c++ interface as a child class

No visible cause for "Unexpected token ILLEGAL"

why you looking for this problem into your code? Even, if it's copypasted.

If you can see, what exactly happening after save file in synced folder - you will see something like ***** at the end of file. It's not related to your code at all.

Solution.

If you are using nginx in vagrant box - add to server config:

sendfile off;

If you are using apache in vagrant box - add to server config:

EnableSendfile Off;

Source of problem: VirtualBox Bug

Adding a module (Specifically pymorph) to Spyder (Python IDE)

You can run:

pip install pymorph

But you need to run that command in the anaconda terminal of your environment. For example:

enter image description here

How to convert TimeStamp to Date in Java?

I have been looking for this since a long time, turns out that Eposh converter does it easily:

long epoch = new java.text.SimpleDateFormat("MM/dd/yyyy HH:mm:ss").parse("01/01/1970 01:00:00").getTime() / 1000;

Or the opposite:

String date = new java.text.SimpleDateFormat("MM/dd/yyyy HH:mm:ss").format(new java.util.Date (epoch*1000));

adb not finding my device / phone (MacOS X)

I had a similar issue. I've discovered that MTP is not supported in OSX. I changed it to PTP, I was promoted to approve my laptop and then my device was finally listed (LG G3).

enter image description here

What's the difference between setWebViewClient vs. setWebChromeClient?

WebViewClient provides the following callback methods, with which you can interfere in how WebView makes a transition to the next content.

void doUpdateVisitedHistory (WebView view, String url, boolean isReload)
void onFormResubmission (WebView view, Message dontResend, Message resend)
void onLoadResource (WebView view, String url)
void onPageCommitVisible (WebView view, String url)
void onPageFinished (WebView view, String url)
void onPageStarted (WebView view, String url, Bitmap favicon)
void onReceivedClientCertRequest (WebView view, ClientCertRequest request)
void onReceivedError (WebView view, int errorCode, String description, String failingUrl)
void onReceivedError (WebView view, WebResourceRequest request, WebResourceError error)
void onReceivedHttpAuthRequest (WebView view, HttpAuthHandler handler, String host, String realm)
void onReceivedHttpError (WebView view, WebResourceRequest request, WebResourceResponse errorResponse)
void onReceivedLoginRequest (WebView view, String realm, String account, String args)
void onReceivedSslError (WebView view, SslErrorHandler handler, SslError error)
boolean onRenderProcessGone (WebView view, RenderProcessGoneDetail detail)
void onSafeBrowsingHit (WebView view, WebResourceRequest request, int threatType, SafeBrowsingResponse callback)
void onScaleChanged (WebView view, float oldScale, float newScale)
void onTooManyRedirects (WebView view, Message cancelMsg, Message continueMsg)
void onUnhandledKeyEvent (WebView view, KeyEvent event)
WebResourceResponse shouldInterceptRequest (WebView view, WebResourceRequest request)
WebResourceResponse shouldInterceptRequest (WebView view, String url)
boolean shouldOverrideKeyEvent (WebView view, KeyEvent event)
boolean shouldOverrideUrlLoading (WebView view, WebResourceRequest request)
boolean shouldOverrideUrlLoading (WebView view, String url)

WebChromeClient provides the following callback methods, with which your Activity or Fragment can update the surroundings of WebView.

Bitmap getDefaultVideoPoster ()
View getVideoLoadingProgressView ()
void getVisitedHistory (ValueCallback<String[]> callback)
void onCloseWindow (WebView window)
boolean onConsoleMessage (ConsoleMessage consoleMessage)
void onConsoleMessage (String message, int lineNumber, String sourceID)
boolean onCreateWindow (WebView view, boolean isDialog, boolean isUserGesture, Message resultMsg)
void onExceededDatabaseQuota (String url, String databaseIdentifier, long quota, long estimatedDatabaseSize, long totalQuota, WebStorage.QuotaUpdater quotaUpdater)
void onGeolocationPermissionsHidePrompt ()
void onGeolocationPermissionsShowPrompt (String origin, GeolocationPermissions.Callback callback)
void onHideCustomView ()
boolean onJsAlert (WebView view, String url, String message, JsResult result)
boolean onJsBeforeUnload (WebView view, String url, String message, JsResult result)
boolean onJsConfirm (WebView view, String url, String message, JsResult result)
boolean onJsPrompt (WebView view, String url, String message, String defaultValue, JsPromptResult result)
boolean onJsTimeout ()
void onPermissionRequest (PermissionRequest request)
void onPermissionRequestCanceled (PermissionRequest request)
void onProgressChanged (WebView view, int newProgress)
void onReachedMaxAppCacheSize (long requiredStorage, long quota, WebStorage.QuotaUpdater quotaUpdater)
void onReceivedIcon (WebView view, Bitmap icon)
void onReceivedTitle (WebView view, String title)
void onReceivedTouchIconUrl (WebView view, String url, boolean precomposed)
void onRequestFocus (WebView view)
void onShowCustomView (View view, int requestedOrientation, WebChromeClient.CustomViewCallback callback)
void onShowCustomView (View view, WebChromeClient.CustomViewCallback callback)
boolean onShowFileChooser (WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams)

laravel select where and where condition

After reading your previous comments, it's clear that you misunderstood the Hash::make function. Hash::make uses bcrypt hashing. By design, this means that every time you run Hash::make('password'), the result will be different (due to random salting). That's why you can't verify the password by simply checking the hashed password against the hashed input.

The proper way to validate a hash is by using:

Hash::check($passwordToCheck, $hashedPassword);

So, for example, your login function would be implemented like this:

public static function login($email, $password) {
    $user = User::whereEmail($email)->first();
    if ( !$user ) return null;  //check if user exists
    if ( Hash::check($password, $user->password) ) {
        return $user;
    } else return null;
}

And then you'd call it like this:

$user = User::login('[email protected]', 'password');
if ( !$user ) echo "Invalid credentials.";
else echo "First name: $user->firstName";

I recommend reviewing the Laravel security documentation, as functions already exist in Laravel to perform this type of authorization.

Furthermore, if your custom-made hashing algorithm generates the same hash every time for a given input, it's a security risk. A good one-way hashing algorithm should use random salting.

How do I import material design library to Android Studio?

There is a new official design library, just add this to your build.gradle: for details visit android developers page

compile 'com.android.support:design:27.0.0'

How do I remove background-image in css?

background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #fff), color-stop(0.5, #fff));
background-image: -webkit-linear-gradient(center top, #fff 0%, #fff 50%);
background-image: -moz-linear-gradient(center top, #fff 0%, #fff 50%);
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#ffffff', GradientType=0);
background-image: linear-gradient(to bottom, #fff 0%, #fff 50%);

for older browsers.. if you have defined css in some framewokrk.css like select2.css in IE9 background-image: -webkit-gradient etc. and you want it via another .css rewrite with "background-image: none !important" not works. I used same color to color gradient like page background color.

How to retrieve JSON Data Array from ExtJS Store

A simple way to do this is

var jsonArray = store.data.items

So if your JSON store is

[{"text": "ABC"}, {"text": "DEF"},{"text": "GHI"},{"text": "JKL"}]

Then you can retreive "DEF" as

jsonArray[1].data.text

In the following code, I noticed that it converts each and every character into an array item.

var jsonData = Ext.encode(Ext.pluck(store.data.items, 'data'));

HTML/CSS - Adding an Icon to a button

You could add a span before the link with a specific class like so:

<div class="btn btn_red"><span class="icon"></span><a href="#">Crimson</a><span></span></div>

And then give that a specific width and a background image just like you are doing with the button itself.

.btn span.icon {
    background: url(imgs/icon.png) no-repeat;
    float: left;
    width: 10px;
    height: 40px;
}

I am no CSS guru but off the top of my head I think that should work.

Dynamically create checkbox with JQuery from text input

One of the elements to consider as you design your interface is on what event (when A takes place, B happens...) does the new checkbox end up being added?

Let's say there is a button next to the text box. When the button is clicked the value of the textbox is turned into a new checkbox. Our markup could resemble the following...

<div id="checkboxes">
    <input type="checkbox" /> Some label<br />
    <input type="checkbox" /> Some other label<br />
</div>

<input type="text" id="newCheckText" /> <button id="addCheckbox">Add Checkbox</button>

Based on this markup your jquery could bind to the click event of the button and manipulate the DOM.

$('#addCheckbox').click(function() {
    var text = $('#newCheckText').val();
    $('#checkboxes').append('<input type="checkbox" /> ' + text + '<br />');
});

How to set a cron job to run every 3 hours

Change Minute to be 0. That's it :)

Note: you can check your "crons" in http://cronchecker.net/

Example

replace anchor text with jquery

To reference an element by id, you need to use the # qualifier.

Try:

alert($("#link1").text());

To replace it, you could use:

$("#link1").text('New text');

The .html() function would work in this case too.

how to activate a textbox if I select an other option in drop down box

Below is the core JavaScript you need to write:

<html> 
<head>  
<script type="text/javascript">
function CheckColors(val){
 var element=document.getElementById('color');
 if(val=='pick a color'||val=='others')
   element.style.display='block';
 else  
   element.style.display='none';
}

</script> 
</head>
<body>
  <select name="color" onchange='CheckColors(this.value);'> 
    <option>pick a color</option>  
    <option value="red">RED</option>
    <option value="blue">BLUE</option>
    <option value="others">others</option>
  </select>
<input type="text" name="color" id="color" style='display:none;'/>
</body>
</html>

Python WindowsError: [Error 123] The filename, directory name, or volume label syntax is incorrect:

As it solved the problem, I put it as an answer.

Don't use single and double quotes, especially when you define a raw string with r in front of it.

The correct call is then

path = r"C:\Apps\CorVu\DATA\Reports\AlliD\Monthly Commission Reports\Output\pdcom1"

or

path = r'C:\Apps\CorVu\DATA\Reports\AlliD\Monthly Commission Reports\Output\pdcom1'

Returning from a void function

An old question, but I'll answer anyway. The answer to the actual question asked is that the bare return is redundant and should be left out.

Furthermore, the suggested value is false for the following reason:

if (ret<0) return;

Redefining a C reserved word as a macro is a bad idea on the face of it, but this particular suggestion is simply unsupportable, both as an argument and as code.

Selected value for JSP drop down using JSTL

I think above examples are correct. but you dont' really need to set

request.setAttribute("selectedDept", selectedDept);

you can reuse that info from JSTL, just do something like this..

<!DOCTYPE html>
<html lang="en">
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<head>
    <script src="../js/jquery-1.8.1.min.js"></script>
</head>
<body>
    <c:set var="authors" value="aaa,bbb,ccc,ddd,eee,fff,ggg" scope="application" />
    <c:out value="Before : ${param.Author}"/>
    <form action="TestSelect.action">
        <label>Author
            <select id="Author" name="Author">
                <c:forEach items="${fn:split(authors, ',')}" var="author">
                    <option value="${author}" ${author == param.Author ? 'selected' : ''}>${author}</option>
                </c:forEach>
            </select>
        </label>
        <button type="submit" value="submit" name="Submit"></button>
        <Br>
        <c:out value="After :   ${param.Author}"/>
    </form>
</body>
</html>

Where to change default pdf page width and font size in jspdf.debug.js?

Besides using one of the default formats you can specify any size you want in the unit you specify.

For example:

// Document of 210mm wide and 297mm high
new jsPDF('p', 'mm', [297, 210]);
// Document of 297mm wide and 210mm high
new jsPDF('l', 'mm', [297, 210]);
// Document of 5 inch width and 3 inch high
new jsPDF('l', 'in', [3, 5]);

The 3rd parameter of the constructor can take an array of the dimensions. However they do not correspond to width and height, instead they are long side and short side (or flipped around).

Your 1st parameter (landscape or portrait) determines what becomes the width and the height.

In the sourcecode on GitHub you can see the supported units (relative proportions to pt), and you can also see the default page formats (with their sizes in pt).

Text File Parsing in Java

Have a look at these pages. They contain many open source CSV parsers. JSaPar is one of them.

start/play embedded (iframe) youtube-video on click of an image

You are supposed to be able to specify a domain that is safe for scripting. the api document mentions "As an extra security measure, you should also include the origin parameter to the URL" http://code.google.com/apis/youtube/iframe_api_reference.html src="http://www.youtube.com/embed/J---aiyznGQ?enablejsapi=1&origin=mydomain.com" would be the src of your iframe.

however it is not very well documented. I am trying something similar right now.

Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript?

I have a solution for that, tailor it to your own needs, an excerpt from one of my libs:

    elvisStructureSeparator: '.',

    // An Elvis operator replacement. See:
    // http://coffeescript.org/ --> The Existential Operator
    // http://fantom.org/doc/docLang/Expressions.html#safeInvoke
    //
    // The fn parameter has a SPECIAL SYNTAX. E.g.
    // some.structure['with a selector like this'].value transforms to
    // 'some.structure.with a selector like this.value' as an fn parameter.
    //
    // Configurable with tulebox.elvisStructureSeparator.
    //
    // Usage examples: 
    // tulebox.elvis(scope, 'arbitrary.path.to.a.function', fnParamA, fnParamB, fnParamC);
    // tulebox.elvis(this, 'currentNode.favicon.filename');
    elvis: function (scope, fn) {
        tulebox.dbg('tulebox.elvis(' + scope + ', ' + fn + ', args...)');

        var implicitMsg = '....implicit value: undefined ';

        if (arguments.length < 2) {
            tulebox.dbg(implicitMsg + '(1)');
            return undefined;
        }

        // prepare args
        var args = [].slice.call(arguments, 2);
        if (scope === null || fn === null || scope === undefined || fn === undefined 
            || typeof fn !== 'string') {
            tulebox.dbg(implicitMsg + '(2)');
            return undefined;   
        }

        // check levels
        var levels = fn.split(tulebox.elvisStructureSeparator);
        if (levels.length < 1) {
            tulebox.dbg(implicitMsg + '(3)');
            return undefined;
        }

        var lastLevel = scope;

        for (var i = 0; i < levels.length; i++) {
            if (lastLevel[levels[i]] === undefined) {
                tulebox.dbg(implicitMsg + '(4)');
                return undefined;
            }
            lastLevel = lastLevel[levels[i]];
        }

        // real return value
        if (typeof lastLevel === 'function') {
            var ret = lastLevel.apply(scope, args);
            tulebox.dbg('....function value: ' + ret);
            return ret;
        } else {
            tulebox.dbg('....direct value: ' + lastLevel);
            return lastLevel;
        }
    },

works like a charm. Enjoy the less pain!

Cast to generic type in C#

You can write a method that takes the type as a generic parameter:

void GenericProcessMessage<T>(T message)
{
    MessageProcessor<T> processor = messageProcessors[typeof(T)]
        as MessageProcessor<T>;

    //  Call method processor or whatever you need to do
}

Then you need a way to call the method with the correct generic argument. You can do this with reflection:

public void ProcessMessage(object message)
{
    Type messageType = message.GetType();
    MethodInfo method = this.GetType().GetMethod("GenericProcessMessage");
    MethodInfo closedMethod = method.MakeGenericMethod(messageType);
    closedMethod.Invoke(this, new object[] {message});
}

Java get last element of a collection

To avoid some of the problems mentioned above (not robust for nulls etc etc), to get first and last element in a list an approach could be

import java.util.List;

public static final <A> A getLastElement(List<A> list) {
    return list != null ? getElement(list, list.size() - 1) : null;
}

public static final <A> A getFirstElement(List<A> list) {
    return list != null ? getElement(list, 0) : null;
}   

private static final <A> A getElement(List<A> list, int pointer) {
    A res = null;
    if (list.size() > 0) {
        res = list.get(pointer);            
    }
    return res;
}

The convention adopted is that the first/last element of an empty list is null...

AlertDialog.Builder with custom layout and EditText; cannot access view

In case any one wants it in Kotlin :

val dialogBuilder = AlertDialog.Builder(this)
// ...Irrelevant code for customizing the buttons and title
val dialogView = layoutInflater.inflate(R.layout.alert_label_editor, null)
dialogBuilder.setView(dialogView)

val editText =  dialogView.findViewById(R.id.label_field)
editText.setText("test label")
val alertDialog = dialogBuilder.create()
alertDialog.show()

Reposted @user370305's answer.

Size-limited queue that holds last N elements in Java

I like @FractalizeR solution. But I would in addition keep and return the value from super.add(o)!

public class LimitedQueue<E> extends LinkedList<E> {

    private int limit;

    public LimitedQueue(int limit) {
        this.limit = limit;
    }

    @Override
    public boolean add(E o) {
        boolean added = super.add(o);
        while (added && size() > limit) {
           super.remove();
        }
        return added;
    }
}

What is the difference between aggregation, composition and dependency?

Aggregation implies a relationship where the child can exist independently of the parent. Example: Class (parent) and Student (child). Delete the Class and the Students still exist.

Composition implies a relationship where the child cannot exist independent of the parent. Example: House (parent) and Room (child). Rooms don't exist separate to a House.

The above two are forms of containment (hence the parent-child relationships).

Dependency is a weaker form of relationship and in code terms indicates that a class uses another by parameter or return type.

Dependency is a form of association.

C# error: "An object reference is required for the non-static field, method, or property"

It looks like you want:

public static string GetRandomBits()

Without static, you would need an object before you can call the GetRandomBits() method. However, since the implementation of GetRandomBits() does not depend on the state of any Program object, it's best to declare it static.

How do I merge a git tag onto a branch

I'm late to the game here, but another approach could be:

1) create a branch from the tag ($ git checkout -b [new branch name] [tag name])

2) create a pull-request to merge with your new branch into the destination branch

How to plot vectors in python using matplotlib

What did you expect the following to do?

v1 = [0,0],[M[i,0],M[i,1]]
v1 = [M[i,0]],[M[i,1]]

This is making two different tuples, and you overwrite what you did the first time... Anyway, matplotlib does not understand what a "vector" is in the sense you are using. You have to be explicit, and plot "arrows":

In [5]: ax = plt.axes()

In [6]: ax.arrow(0, 0, *v1, head_width=0.05, head_length=0.1)
Out[6]: <matplotlib.patches.FancyArrow at 0x114fc8358>

In [7]: ax.arrow(0, 0, *v2, head_width=0.05, head_length=0.1)
Out[7]: <matplotlib.patches.FancyArrow at 0x115bb1470>

In [8]: plt.ylim(-5,5)
Out[8]: (-5, 5)

In [9]: plt.xlim(-5,5)
Out[9]: (-5, 5)

In [10]: plt.show()

Result:

enter image description here

Handling of non breaking space: <p>&nbsp;</p> vs. <p> </p>

If I understand your issue this should work

&emsp—the em space; this should be a very wide space, typically as much as four real spaces. &ensp—the en space; this should be a somewhat wide space, roughly two regular spaces. &thinsp—this will be a narrow space, even more narrow than a regular space.

Sources: http://hea-www.harvard.edu/~fine/Tech/html-sentences.html

How can I check if the array of objects have duplicate property values?

Try an simple loop:

var repeat = [], tmp, i = 0;

while(i < values.length){
  repeat.indexOf(tmp = values[i++].name) > -1 ? values.pop(i--) : repeat.push(tmp)
}

Demo

How to install ia32-libs in Ubuntu 14.04 LTS (Trusty Tahr)

The problem is that in many cases the packages are multiarch already so the i386 package is not available, but other packages still depend on the i386 package only. This is a problem in the repository, and the managers of the repos should fix it

Printf width specifier to maintain precision of floating-point value

Simply use the macros from <float.h> and the variable-width conversion specifier (".*"):

float f = 3.14159265358979323846;
printf("%.*f\n", FLT_DIG, f);

Docker Error bind: address already in use

docker-compose down --rmi all 

and then restart your computer

Debug assertion failed. C++ vector subscript out of range

Regardless of how do you index the pushbacks your vector contains 10 elements indexed from 0 (0, 1, ..., 9). So in your second loop v[j] is invalid, when j is 10.

This will fix the error:

for(int j = 9;j >= 0;--j)
{
    cout << v[j];
}

In general it's better to think about indexes as 0 based, so I suggest you change also your first loop to this:

for(int i = 0;i < 10;++i)
{
    v.push_back(i);
}

Also, to access the elements of a container, the idiomatic approach is to use iterators (in this case: a reverse iterator):

for (vector<int>::reverse_iterator i = v.rbegin(); i != v.rend(); ++i)
{
    std::cout << *i << std::endl;
}

Changing Shell Text Color (Windows)

This is extremely simple! Rather than importing odd modules for python or trying long commands you can take advantage of windows OS commands.

In windows, commands exist to change the command prompt text color. You can use this in python by starting with a: import os

Next you need to have a line changing the text color, place it were you want in your code. os.system('color 4')

You can figure out the other colors by starting cmd.exe and typing color help.

The good part? Thats all their is to it, to simple lines of code. -Day

How to get PID of process I've just started within java program?

the jnr-process project provides this capability.

It is part of the java native runtime used by jruby and can be considered a prototype for a future java-FFI

What does it mean to have an index to scalar variable error? python

IndexError: invalid index to scalar variable happens when you try to index a numpy scalar such as numpy.int64 or numpy.float64. It is very similar to TypeError: 'int' object has no attribute '__getitem__' when you try to index an int.

>>> a = np.int64(5)
>>> type(a)
<type 'numpy.int64'>
>>> a[3]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: invalid index to scalar variable.
>>> a = 5
>>> type(a)
<type 'int'>
>>> a[3]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'int' object has no attribute '__getitem__'

Android disable screen timeout while app is running

Its importante to note that these methods all must be run from the UI thread to work. See changing KeepScreenOn from javascript in Android cordova app

What is Model in ModelAndView from Spring MVC?

It is all explained by the javadoc for the constructor. It is a convenience constructor that populates the model with one attribute / value pair.

So ...

   new ModelAndView(view, name, value);

is equivalent to:

   Map model = ...
   model.put(name, value);
   new ModelAndView(view, model);

What is the difference between `throw new Error` and `throw someObject`?

TLDR: they are equivalent Error(x) === new Error(x).

// this:
const x = Error('I was created using a function call!');
????// has the same functionality as this:
const y = new Error('I was constructed via the "new" keyword!');

source: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error

throw and throw Error will are functionally equivalent. But when you catch them and serialize them to console.log they are not serialized exactly the same way:

throw 'Parameter is not a number!';
throw new Error('Parameter is not a number!');
throw Error('Parameter is not a number!');

Console.log(e) of the above will produce 2 different results:

Parameter is not a number!
Error: Parameter is not a number!
Error: Parameter is not a number!

How to enable C++11/C++0x support in Eclipse CDT?

Neither the hack nor the cleaner version work for Indigo. The hack is ignored, and the required configuration options are missing. For no apparent reason, build started working after not working and not providing any useful reason why. At least from the command line, I get reproducible results.

find first sequence item that matches a criterion

a=[100,200,300,400,500]
def search(b):
 try:
  k=a.index(b)
  return a[k] 
 except ValueError:
    return 'not found'
print(search(500))

it'll return the object if found else it'll return "not found"

How to use ? : if statements with Razor and inline code blocks

This should work:

<span class="vote-up@(puzzle.UserVote == VoteType.Up ? "-selected" : "")">Vote Up</span>

GitHub: How to make a fork of public repository private?

The answers are correct but don't mention how to sync code between the public repo and the fork.

Here is the full workflow (we've done this before open sourcing React Native):


First, duplicate the repo as others said (details here):

Create a new repo (let's call it private-repo) via the Github UI. Then:

git clone --bare https://github.com/exampleuser/public-repo.git
cd public-repo.git
git push --mirror https://github.com/yourname/private-repo.git
cd ..
rm -rf public-repo.git

Clone the private repo so you can work on it:

git clone https://github.com/yourname/private-repo.git
cd private-repo
make some changes
git commit
git push origin master

To pull new hotness from the public repo:

cd private-repo
git remote add public https://github.com/exampleuser/public-repo.git
git pull public master # Creates a merge commit
git push origin master

Awesome, your private repo now has the latest code from the public repo plus your changes.


Finally, to create a pull request private repo -> public repo:

Use the GitHub UI to create a fork of the public repo (the small "Fork" button at the top right of the public repo page). Then:

git clone https://github.com/yourname/the-fork.git
cd the-fork
git remote add private_repo_yourname https://github.com/yourname/private-repo.git
git checkout -b pull_request_yourname
git pull private_repo_yourname master
git push origin pull_request_yourname

Now you can create a pull request via the Github UI for public-repo, as described here.

Once project owners review your pull request, they can merge it.

Of course the whole process can be repeated (just leave out the steps where you add remotes).

How do I hide certain files from the sidebar in Visual Studio Code?

For .meta files while using Unity3D, I found the best pattern for hiding is:

"files.exclude": {
  "*/**/**.meta": true
}

This captures all folders and subfolders, and will pick up foo.cs.meta in addition to foo.meta

How to check if android checkbox is checked within its onClick method (declared in XML)?

This will do the trick:

  public void itemClicked(View v) {
    if (((CheckBox) v).isChecked()) {
        Toast.makeText(MyAndroidAppActivity.this,
           "Checked", Toast.LENGTH_LONG).show();
    }
  }

How to check if variable's type matches Type stored in a variable

You need to see if the Type of your instance is equal to the Type of the class. To get the type of the instance you use the GetType() method:

 u.GetType().Equals(t);

or

 u.GetType.Equals(typeof(User));

should do it. Obviously you could use '==' to do your comparison if you prefer.

How do you properly use WideCharToMultiByte

Elaborating on the answer provided by Brian R. Bondy: Here's an example that shows why you can't simply size the output buffer to the number of wide characters in the source string:

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

/* string consisting of several Asian characters */
wchar_t wcsString[] = L"\u9580\u961c\u9640\u963f\u963b\u9644";

int main() 
{

    size_t wcsChars = wcslen( wcsString);

    size_t sizeRequired = WideCharToMultiByte( 950, 0, wcsString, -1, 
                                               NULL, 0,  NULL, NULL);

    printf( "Wide chars in wcsString: %u\n", wcsChars);
    printf( "Bytes required for CP950 encoding (excluding NUL terminator): %u\n",
             sizeRequired-1);

    sizeRequired = WideCharToMultiByte( CP_UTF8, 0, wcsString, -1,
                                        NULL, 0,  NULL, NULL);
    printf( "Bytes required for UTF8 encoding (excluding NUL terminator): %u\n",
             sizeRequired-1);
}

And the output:

Wide chars in wcsString: 6
Bytes required for CP950 encoding (excluding NUL terminator): 12
Bytes required for UTF8 encoding (excluding NUL terminator): 18

window.onload vs document.onload

According to Parsing HTML documents - The end,

  1. The browser parses the HTML source and runs deferred scripts.

  2. A DOMContentLoaded is dispatched at the document when all the HTML has been parsed and have run. The event bubbles to the window.

  3. The browser loads resources (like images) that delay the load event.

  4. A load event is dispatched at the window.

Therefore, the order of execution will be

  1. DOMContentLoaded event listeners of window in the capture phase
  2. DOMContentLoaded event listeners of document
  3. DOMContentLoaded event listeners of window in the bubble phase
  4. load event listeners (including onload event handler) of window

A bubble load event listener (including onload event handler) in document should never be invoked. Only capture load listeners might be invoked, but due to the load of a sub-resource like a stylesheet, not due to the load of the document itself.

_x000D_
_x000D_
window.addEventListener('DOMContentLoaded', function() {_x000D_
  console.log('window - DOMContentLoaded - capture'); // 1st_x000D_
}, true);_x000D_
document.addEventListener('DOMContentLoaded', function() {_x000D_
  console.log('document - DOMContentLoaded - capture'); // 2nd_x000D_
}, true);_x000D_
document.addEventListener('DOMContentLoaded', function() {_x000D_
  console.log('document - DOMContentLoaded - bubble'); // 2nd_x000D_
});_x000D_
window.addEventListener('DOMContentLoaded', function() {_x000D_
  console.log('window - DOMContentLoaded - bubble'); // 3rd_x000D_
});_x000D_
_x000D_
window.addEventListener('load', function() {_x000D_
  console.log('window - load - capture'); // 4th_x000D_
}, true);_x000D_
document.addEventListener('load', function(e) {_x000D_
  /* Filter out load events not related to the document */_x000D_
  if(['style','script'].indexOf(e.target.tagName.toLowerCase()) < 0)_x000D_
    console.log('document - load - capture'); // DOES NOT HAPPEN_x000D_
}, true);_x000D_
document.addEventListener('load', function() {_x000D_
  console.log('document - load - bubble'); // DOES NOT HAPPEN_x000D_
});_x000D_
window.addEventListener('load', function() {_x000D_
  console.log('window - load - bubble'); // 4th_x000D_
});_x000D_
_x000D_
window.onload = function() {_x000D_
  console.log('window - onload'); // 4th_x000D_
};_x000D_
document.onload = function() {_x000D_
  console.log('document - onload'); // DOES NOT HAPPEN_x000D_
};
_x000D_
_x000D_
_x000D_

How do I escape ampersands in XML so they are rendered as entities in HTML?

I have tried &amp, but it didn't work. Based on Wim ten Brink's answer I tried &amp;amp and it worked.

One of my fellow developers suggested me to use &#x26; and that worked regardless of how many times it may be rendered.

Using Node.js require vs. ES6 import/export

I personally use import because, we can import the required methods, members by using import.

import {foo, bar} from "dep";

FileName: dep.js

export foo function(){};
export const bar = 22

Credit goes to Paul Shan. More info.

How to solve "The directory is not empty" error when running rmdir command in a batch script?

Im my case i just moved the folder to root directory like so.

move <source directory> c:\

And then ran the command to remove the directory

rmdir c:\<moved directory> /s /q

Make div 100% Width of Browser Window

.myDiv {
    background-color: red;
    width: 100%;
    min-height: 100vh;
    max-height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    margin: 0 auto;
}

Basically, we're fixing the div's position regardless of it's parent, and then position it using margin: 0 auto; and settings its position at the top left corner.

What is JSONP, and why was it created?

JSONP is a great away to get around cross-domain scripting errors. You can consume a JSONP service purely with JS without having to implement a AJAX proxy on the server side.

You can use the b1t.co service to see how it works. This is a free JSONP service that alllows you to minify your URLs. Here is the url to use for the service:

http://b1t.co/Site/api/External/MakeUrlWithGet?callback=[resultsCallBack]&url=[escapedUrlToMinify]

For example the call, http://b1t.co/Site/api/External/MakeUrlWithGet?callback=whateverJavascriptName&url=google.com

would return

whateverJavascriptName({"success":true,"url":"http://google.com","shortUrl":"http://b1t.co/54"});

And thus when that get's loaded in your js as a src, it will automatically run whateverJavascriptName which you should implement as your callback function:

function minifyResultsCallBack(data)
{
    document.getElementById("results").innerHTML = JSON.stringify(data);
}

To actually make the JSONP call, you can do it about several ways (including using jQuery) but here is a pure JS example:

function minify(urlToMinify)
{
   url = escape(urlToMinify);
   var s = document.createElement('script');
   s.id = 'dynScript';
   s.type='text/javascript';
   s.src = "http://b1t.co/Site/api/External/MakeUrlWithGet?callback=resultsCallBack&url=" + url;
   document.getElementsByTagName('head')[0].appendChild(s);
}

A step by step example and a jsonp web service to practice on is available at: this post

How to get URI from an asset File?

The correct url is:

file:///android_asset/RELATIVEPATH

where RELATIVEPATH is the path to your resource relative to the assets folder.

Note the 3 /'s in the scheme. Web view would not load any of my assets without the 3. I tried 2 as (previously) commented by CommonsWare and it wouldn't work. Then I looked at CommonsWare's source on github and noticed the extra forward slash.

This testing though was only done on the 1.6 Android emulator but I doubt its different on a real device or higher version.

EDIT: CommonsWare updated his answer to reflect this tiny change. So I've edited this so it still makes sense with his current answer.

How do I split a string so I can access item x?

What about using string and values() statement?

DECLARE @str varchar(max)
SET @str = 'Hello John Smith'

DECLARE @separator varchar(max)
SET @separator = ' '

DECLARE @Splited TABLE(id int IDENTITY(1,1), item varchar(max))

SET @str = REPLACE(@str, @separator, '''),(''')
SET @str = 'SELECT * FROM (VALUES(''' + @str + ''')) AS V(A)' 

INSERT INTO @Splited
EXEC(@str)

SELECT * FROM @Splited

Result-set achieved.

id  item
1   Hello
2   John
3   Smith

Why can't overriding methods throw exceptions broader than the overridden method?

Let us take an interview Question. There is a method that throws NullPointerException in the superclass. Can we override it with a method that throws RuntimeException?

To answer this question, let us know what is an Unchecked and Checked exception.

  1. Checked exceptions must be explicitly caught or propagated as described in Basic try-catch-finally Exception Handling. Unchecked exceptions do not have this requirement. They don't have to be caught or declared thrown.

  2. Checked exceptions in Java extend the java.lang.Exception class. Unchecked exceptions extend the java.lang.RuntimeException.

public class NullPointerException extends RuntimeException

Unchecked exceptions extend the java.lang.RuntimeException. Thst's why NullPointerException is an Uncheked exception.

Let's take an example: Example 1 :

    public class Parent {
       public void name()  throws NullPointerException {
           System.out.println(" this is parent");
       }
}

public class Child  extends Parent{
     public  void name() throws RuntimeException{
             System.out.println(" child ");
     }

     public static void main(String[] args) {
        Parent parent  = new Child();
        parent.name();// output => child
    }
}

The program will compile successfully. Example 2:

    public class Parent {
       public void name()  throws RuntimeException {
           System.out.println(" this is parent");
       }
}

public class Child  extends Parent{
     public  void name() throws  NullPointerException {
             System.out.println(" child ");
     }

     public static void main(String[] args) {
        Parent parent  = new Child();
        parent.name();// output => child
    }
}

The program will also compile successfully. Therefore it is evident, that nothing happens in case of Unchecked exceptions. Now, let's take a look what happens in case of Checked exceptions. Example 3: When base class and child class both throws a checked exception

    public class Parent {
       public void name()  throws IOException {
           System.out.println(" this is parent");
       }
}
public class Child  extends Parent{
     public  void name() throws IOException{
             System.out.println(" child ");
     }

     public static void main(String[] args) {
        Parent parent  = new Child();

        try {
            parent.name();// output=> child
        }catch( Exception e) {
            System.out.println(e);
        }

    }
}

The program will compile successfully. Example 4: When child class method is throwing border checked exception compared to the same method of base class.

import java.io.IOException;

public class Parent {
       public void name()  throws IOException {
           System.out.println(" this is parent");
       }
}
public class Child  extends Parent{
     public  void name() throws Exception{ // broader exception
             System.out.println(" child ");
     }

     public static void main(String[] args) {
        Parent parent  = new Child();

        try {
            parent.name();//output=> Compilation failure
        }catch( Exception e) {
            System.out.println(e);
        }

    }
}

The program will fail to compile. So, we have to be careful when we are using Checked exceptions.

How to solve ERR_CONNECTION_REFUSED when trying to connect to localhost running IISExpress - Error 502 (Cannot debug from Visual Studio)?

Ensure Script Debugging is disabled

enter image description here

I was getting this intermittently despite having tried several of the above suggestions. As soon as I disabled this, my debugging my site worked like a dream. (Think I'd only turned it on by accident, or perhaps in a previous life).

How do I read and parse an XML file in C#?

LINQ to XML Example:

// Loading from a file, you can also load from a stream
var xml = XDocument.Load(@"C:\contacts.xml");


// Query the data and write out a subset of contacts
var query = from c in xml.Root.Descendants("contact")
            where (int)c.Attribute("id") < 4
            select c.Element("firstName").Value + " " +
                   c.Element("lastName").Value;


foreach (string name in query)
{
    Console.WriteLine("Contact's Full Name: {0}", name);
}

Reference: LINQ to XML at MSDN

How to create Python egg file

I think you should use python wheels for distribution instead of egg now.

Wheels are the new standard of python distribution and are intended to replace eggs. Support is offered in pip >= 1.4 and setuptools >= 0.8.

jquery can't get data attribute value

Make sure to check if the event related to the button click is not propagating to child elements as an icon tag (<i class="fa...) inside the button for example, so this propagation can make you miss the button $(this).attr('data-X10') and hit the icon tag.

<button data-x10="C5">
    <i class="fa fa-check"></i> Text
</button>

$('button.toggleStatus').on('click', function (event) {
    event.preventDefault();
    event.stopPropagation();
    $(event.currentTarget).attr('data-X10');
});

Is there a way to follow redirects with command line cURL?

I had a similar problem. I am posting my solution here because I believe it might help one of the commenters.

For me, the obstacle was that the page required a login and then gave me a new URL through javascript. Here is what I had to do:

curl -c cookiejar -g -O -J -L -F "j_username=username" -F "j_password=password" <URL>

Note that j_username and j_password is the name of the fields for my website's login form. You will have to open the source of the webpage to see what the 'name' of the username field and the 'name' of the password field is in your case. After that I go an html file with java script in which the new URL was embedded. After parsing this out just resubmit with the new URL:

curl -c cookiejar -g -O -J -L -F "j_username=username" -F "j_password=password" <NEWURL>

How do I delete a Git branch locally and remotely?

Delete remote branch

git push origin :<branchname>

Delete local branch

git branch -D <branchname>

Delete local branch steps:

  1. checkout to another branch
  2. delete local branch

Equivalent of Clean & build in Android Studio?

In latest releases of Android Studio one more option has been added dedicatedly for Clean.

Build > Clean Project 

Visual Studio can't build due to rc.exe

I'm on Windows 10 x64 and Visual Studio 2017. I copied and pasted rc.exe and rcdll.dll from:

C:\Program Files (x86)\Windows Kits\8.1\bin\x86

to

C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\amd64

it's works with: ( qt creator 5.7.1)

Read from a gzip file in python

Try gzipping some data through the gzip libary like this...

import gzip
content = "Lots of content here"
f = gzip.open('Onlyfinnaly.log.gz', 'wb')
f.write(content)
f.close()

... then run your code as posted ...

import gzip
f=gzip.open('Onlyfinnaly.log.gz','rb')
file_content=f.read()
print file_content

This method worked for me as for some reason the gzip library fails to read some files.

How to read request body in an asp.net core webapi controller?

In ASP.Net Core it seems complicated to read several times the body request, however if your first attempt does it the right way, you should be fine for the next attempts.

I read several turnaround for example by substituting the body stream, but I think the following is the cleanest:

The most important points being

  1. to let the request know that you will read its body twice or more times,
  2. to not close the body stream, and
  3. to rewind it to its initial position so the internal process does not get lost.

[EDIT]

As pointed out by Murad, you may also take advantage of the .Net Core 2.1 extension: EnableBuffering It stores large requests onto the disk instead of keeping it in memory, avoiding large-streams issues stored in memory (files, images, ...). You can change the temporary folder by setting ASPNETCORE_TEMP environment variable, and files are deleted once the request is over.

In an AuthorizationFilter, you can do the following:

// Helper to enable request stream rewinds
using Microsoft.AspNetCore.Http.Internal;
[...]
public class EnableBodyRewind : Attribute, IAuthorizationFilter
{
    public void OnAuthorization(AuthorizationFilterContext context)
    {
        var bodyStr = "";
        var req = context.HttpContext.Request;

        // Allows using several time the stream in ASP.Net Core
        req.EnableRewind(); 

        // Arguments: Stream, Encoding, detect encoding, buffer size 
        // AND, the most important: keep stream opened
        using (StreamReader reader 
                  = new StreamReader(req.Body, Encoding.UTF8, true, 1024, true))
        {
            bodyStr = reader.ReadToEnd();
        }

        // Rewind, so the core is not lost when it looks the body for the request
        req.Body.Position = 0;

        // Do whatever work with bodyStr here

    }
}



public class SomeController : Controller
{
    [HttpPost("MyRoute")]
    [EnableBodyRewind]
    public IActionResult SomeAction([FromBody]MyPostModel model )
    {
        // play the body string again
    }
}

Then you can use the body again in the request handler.

In your case if you get a null result, it probably means that the body has already been read at an earlier stage. In that case you may need to use a middleware (see below).

However be careful if you handle large streams, that behavior implies that everything is loaded into memory, this should not be triggered in case of a file upload.

You may want to use this as a Middleware

Mine looks like this (again, if you download/upload large files, this should be disabled to avoid memory issues):

public sealed class BodyRewindMiddleware
{
    private readonly RequestDelegate _next;

    public BodyRewindMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task Invoke(HttpContext context)
    {
        try { context.Request.EnableRewind(); } catch { }
        await _next(context);
        // context.Request.Body.Dipose() might be added to release memory, not tested
    }
}
public static class BodyRewindExtensions
{
    public static IApplicationBuilder EnableRequestBodyRewind(this IApplicationBuilder app)
    {
        if (app == null)
        {
            throw new ArgumentNullException(nameof(app));
        }

        return app.UseMiddleware<BodyRewindMiddleware>();
    }

}

Vim multiline editing like in sublimetext?

There are several ways to accomplish that in Vim. I don't know which are most similar to Sublime Text's though.


The first one would be via multiline insert mode. Put your cursor to the second "a" in the first line, press Ctrl-V, select all lines, then press I, and put in a doublequote. Pressing <esc> will repeat the operation on every line.


The second one is via macros. Put the cursor on the first character, and start recording a macro with qa. Go the your right with llll, enter insert mode with a, put down a doublequote, exit insert mode, and go back to the beginning of your row with <home> (or equivalent). Press j to move down one row. Stop recording with q. And then replay the macro with @a. Several times.


Does any of the above approaches work for you?

Find the version of an installed npm package

Combining some of the above answers and produces a super simple and super quick lookup.
Run from project root. No need to cd into any folder, just 1 line:

node -p "require('SOMEPACKAGE/package.json').version"

Incomplete type is not allowed: stringstream

An incomplete type error is when the compiler encounters the use of an identifier that it knows is a type, for instance because it has seen a forward-declaration of it (e.g. class stringstream;), but it hasn't seen a full definition for it (class stringstream { ... };).

This could happen for a type that you haven't used in your own code but is only present through included header files -- when you've included header files that use the type, but not the header file where the type is defined. It's unusual for a header to not itself include all the headers it needs, but not impossible.

For things from the standard library, such as the stringstream class, use the language standard or other reference documentation for the class or the individual functions (e.g. Unix man pages, MSDN library, etc.) to figure out what you need to #include to use it and what namespace to find it in if any. You may need to search for pages where the class name appears (e.g. man -k stringstream).

What does OpenCV's cvWaitKey( ) function do?

The cvWaitKey simply provides something of a delay. For example:

char c = cvWaitKey(33);
if( c == 27 ) break;

Tis was apart of my code in which a video was loaded into openCV and the frames outputted. The 33 number in the code means that after 33ms, a new frame would be shown. Hence, the was a dely or time interval of 33ms between each frame being shown on the screen. Hope this helps.

How to loop through all the files in a directory in c # .net?

You can have a look at this page showing Deep Folder Copy, it uses recursive means to iterate throught the files and has some really nice tips, like filtering techniques etc.

http://www.codeproject.com/Tips/512208/Folder-Directory-Deep-Copy-including-sub-directori

Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.Button.Borderless.Colored'

The ideal answer found in the forum mentioned above is this:

sed -i 's/facebook-android-sdk:4.+/facebook-android-sdk:4.22.1/g' ./node_modules/react-native-fbsdk/android/build.gradle

This works

Get clicked item and its position in RecyclerView

Use below code:-

public class SergejAdapter extends RecyclerView.Adapter<SergejAdapter.MyViewHolder>{

...

class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{


    @Override
    public void onClick(View v) {
        // here you use position
        int position = getAdapterPosition();
        ...

    }
}
}

Dynamically generating a QR code with PHP

The easiest way to generate QR codes with PHP is the phpqrcode library.

AngularJS - difference between pristine/dirty and touched/untouched

It's worth mentioning that the validation properties are different for forms and form elements (note that touched and untouched are for fields only):

Input fields have the following states:

$untouched The field has not been touched yet
$touched The field has been touched
$pristine The field has not been modified yet
$dirty The field has been modified
$invalid The field content is not valid
$valid The field content is valid

They are all properties of the input field, and are either true or false.

Forms have the following states:

$pristine No fields have been modified yet
$dirty One or more have been modified
$invalid The form content is not valid
$valid The form content is valid
$submitted The form is submitted

They are all properties of the form, and are either true or false.

JUnit test for System.out.println()

You cannot directly print by using system.out.println or using logger api while using JUnit. But if you want to check any values then you simply can use

Assert.assertEquals("value", str);

It will throw below assertion error:

java.lang.AssertionError: expected [21.92] but found [value]

Your value should be 21.92, Now if you will test using this value like below your test case will pass.

 Assert.assertEquals(21.92, str);

Double decimal formatting in Java

Use String.format:

String.format("%.2f", 4.52135);

As per docs:

The locale always used is the one returned by Locale.getDefault().

apache not accepting incoming connections from outside of localhost

this is what worked for us to get the apache accessible from outside:

sudo iptables -I INPUT 4 -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT
sudo service iptables restart

npm throws error without sudo

I ran into this issue, and while it's true that ~/.npm should be owned by your user, npm was not installing the modules there.

What actually solved my issue is this command:

npm config set prefix ~/.npm

It will make sure that all your global installation will go under this prefix. And it's important that your user owns this directory.

How can I have grep not print out 'No such file or directory' errors?

Errors like that are usually sent to the "standard error" stream, which you can pipe to a file or just make disappear on most commands:

grep pattern * -R -n 2>/dev/null

start MySQL server from command line on Mac OS Lion

Try /usr/local/mysql/bin/mysqld_safe

Example:

shell> sudo /usr/local/mysql/bin/mysqld_safe
(Enter your password, if necessary)
(Press Control-Z)
shell> bg
(Press Control-D or enter "exit" to exit the shell)

You can also add these to your bash startup scripts:

export MYSQL_HOME=/usr/local/mysql
alias start_mysql='sudo $MYSQL_HOME/bin/mysqld_safe &'
alias stop_mysql='sudo $MYSQL_HOME/bin/mysqladmin shutdown'

Reading in a JSON File Using Swift

SWIFTYJSON VERSION SWIFT 3

func loadJson(fileName: String) -> JSON {

    var dataPath:JSON!

    if let path : String = Bundle.main.path(forResource: fileName, ofType: "json") {
        if let data = NSData(contentsOfFile: path) {
             dataPath = JSON(data: data as Data)
        }
    }
    return dataPath
}

How to use http.client in Node.js if there is basic authorization

for what it's worth I'm using node.js 0.6.7 on OSX and I couldn't get 'Authorization':auth to work with our proxy, it needed to be set to 'Proxy-Authorization':auth my test code is:

var http = require("http");
var auth = 'Basic ' + new Buffer("username:password").toString('base64');
var options = {
    host: 'proxyserver',
    port: 80,
    method:"GET",
    path: 'http://www.google.com',
    headers:{
        "Proxy-Authorization": auth,
        Host: "www.google.com"
    } 
};
http.get(options, function(res) {
    console.log(res);
    res.pipe(process.stdout);
});

How do you use String.substringWithRange? (or, how do Ranges work in Swift?)

Rob Napier had already given a awesome answer using subscript. But i felt one drawback in that as there is no check for out of bound conditions. This can tend to crash. So i modified the extension and here it is

extension String {
    subscript (r: Range<Int>) -> String? { //Optional String as return value
        get {
            let stringCount = self.characters.count as Int
            //Check for out of boundary condition
            if (stringCount < r.endIndex) || (stringCount < r.startIndex){
                return nil
            }
            let startIndex = self.startIndex.advancedBy(r.startIndex)

            let endIndex = self.startIndex.advancedBy(r.endIndex - r.startIndex)

            return self[Range(start: startIndex, end: endIndex)]
        }
    }
}

Output below

var str2 = "Hello, World"

var str3 = str2[0...5]
//Hello,
var str4 = str2[0..<5]
//Hello
var str5 = str2[0..<15]
//nil

So i suggest always to check for the if let

if let string = str[0...5]
{
    //Manipulate your string safely
}

SSIS Excel Import Forcing Incorrect Column Type

I've seen this issue before, it's Excel that is the issue not SSIS. Excel samples the 1st few rows and then infers the data type even if you explicitly set it to text. What you need to do is put this into the Excel file connection string in the SSIS package. This instruction tells Excel that the columns contain mixed data types and hints it to do extra checking before deciding that the column is a numeric type when in fact it's not.

;Extended Properties="IMEX=1"

It should work with this (in most cases). The safer thing to do is export the Excel data to tab delimited text and use SSIS to import that.

Adding a new value to an existing ENUM Type

PostgreSQL 9.1 introduces ability to ALTER Enum types:

ALTER TYPE enum_type ADD VALUE 'new_value'; -- appends to list
ALTER TYPE enum_type ADD VALUE 'new_value' BEFORE 'old_value';
ALTER TYPE enum_type ADD VALUE 'new_value' AFTER 'old_value';

Javascript array value is undefined ... how do I test for that

array[index] == 'undefined' compares the value of the array index to the string "undefined".
You're probably looking for typeof array[index] == 'undefined', which compares the type.

HTML input - name vs. id

Adding some actual references to W3 docs that authoritatively explain the role of the 'name' attribute on form elements. (For what it's worth, I arrived here while exploring exactly how Stripe.js works to implement safe interaction with payment gateway Stripe. In particular, what causes a form input element to get submitted back to the server, or prevents it from being submitted?)

The following W3 docs are relevent:

HTML 4: https://www.w3.org/TR/html401/interact/forms.html#control-name Section 17.2 Controls

HTML 5: https://www.w3.org/TR/html5/forms.html#form-submission-0 and https://www.w3.org/TR/html5/forms.html#constructing-the-form-data-set Section 4.10.22.4 Constructing the form data set.

As explained therein, an input element will be submitted by the browser if and only if it has a valid 'name' attribute.

As others have noted, the 'id' attribute uniquely identifies DOM elements, but is not involved in normal form submission. (Though 'id' or other attributes can of course be used by javascript to obtain form values, which javascript could then use for AJAX submissions and so on.)

One oddity regarding previous answers/commenters concern about id's values and name's values being in the same namespace. So far as I can tell from the specs, this applied to some deprecated uses of the name attribute (not on form elements). For example https://www.w3.org/TR/html5/obsolete.html:

"Authors should not specify the name attribute on a elements. If the attribute is present, its value must not be the empty string and must neither be equal to the value of any of the IDs in the element's home subtree other than the element's own ID, if any, nor be equal to the value of any of the other name attributes on a elements in the element's home subtree. If this attribute is present and the element has an ID, then the attribute's value must be equal to the element's ID. In earlier versions of the language, this attribute was intended as a way to specify possible targets for fragment identifiers in URLs. The id attribute should be used instead."

Clearly in this special case there's some overlap between id and name values for 'a' tags. But this seems to be a peculiarity of processing for fragment ids, not due to general sharing of namespace of ids and names.

DateTime "null" value

I'd consider using a nullable types.

DateTime? myDate instead of DateTime myDate.

IntelliJ shortcut to show a popup of methods in a class that can be searched

On linux distributions (@least on Debian with plasma) the default shortcut is

Ctrl + 0

.bashrc: Permission denied

.bashrc is not meant to be executed but sourced. Try this instead:

. ~/.bashrc

Cheers!

Get all attributes of an element using jQuery

A debugging script (jquery solution based on the answer above by hashchange)

function getAttributes ( $node ) {
      $.each( $node[0].attributes, function ( index, attribute ) {
      console.log(attribute.name+':'+attribute.value);
   } );
}

getAttributes($(this));  // find out what attributes are available

Get properties and values from unknown object

This example trims all the string properties of an object.

public static void TrimModelProperties(Type type, object obj)
{
    var propertyInfoArray = type.GetProperties(
                                    BindingFlags.Public | 
                                    BindingFlags.Instance);
    foreach (var propertyInfo in propertyInfoArray)
    {
        var propValue = propertyInfo.GetValue(obj, null);
        if (propValue == null) 
            continue;
        if (propValue.GetType().Name == "String")
            propertyInfo.SetValue(
                             obj, 
                             ((string)propValue).Trim(), 
                             null);
    }
}

Random character generator with a range of (A..Z, 0..9) and punctuation

Using some simple command line (bash scripting):

$ cat /dev/urandom | tr -cd 'a-z0-9,.?/\-' | head -c 30 | xargs
t315,qeqaszwz6kxv?761rf.cj/7gc

$ cat /dev/urandom | tr -cd 'a-z0-9,.?/\-' | head -c 1 | xargs
f
  • cat /dev/urandom: get a random stream of char from the kernel
  • tr: keep only char char we want
  • head: take only the first n chars
  • xargs: just for adding a '\n' char

What is lexical scope?

Here's a different angle on this question that we can get by taking a step back and looking at the role of scoping in the larger framework of interpretation (running a program). In other words, imagine that you were building an interpreter (or compiler) for a language and were responsible for computing the output, given a program and some input to it.

Interpretation involves keeping track of three things:

  1. State - namely, variables and referenced memory locations on the heap and stack.

  2. Operations on that state - namely, every line of code in your program

  3. The environment in which a given operation runs - namely, the projection of state on an operation.

An interpreter starts at the first line of code in a program, computes its environment, runs the line in that environment and captures its effect on the program's state. It then follows the program's control flow to execute the next line of code, and repeats the process till the program ends.

The way you compute the environment for any operation is through a formal set of rules defined by the programming language. The term "binding" is frequently used to describe the mapping of the overall state of the program to a value in the environment. Note that by "overall state" we do not mean global state, but rather the sum total of every reachable definition, at any point in the execution).

This is the framework in which the scoping problem is defined. Now to the next part of what our options are.

  • As the implementor of the interpreter, you could simplify your task by making the environment as close as possible to the program's state. Accordingly, the environment of a line of code would simply be defined by environment of the previous line of code with the effects of that operation applied to it, regardless of whether the previous line was an assignment, a function call, return from a function, or a control structure such as a while loop.

This is the gist of dynamic scoping, wherein the environment that any code runs in is bound to the state of the program as defined by its execution context.

  • Or, you could think of a programmer using your language and simplify his or her task of keeping track of the values a variable can take. There are way too many paths and too much complexity involved in reasoning about the outcome the totality of past execution. Lexical Scoping helps do this by restricting the current environment to the portion of state defined in the current block, function or other unit of scope, and its parent (i.e. the block enclosing the current clock, or the function that called the present function).

In other words, with lexical scope the environment that any code sees is bound to state associated with a scope defined explicitly in the language, such as a block or a function.

How do I assert my exception message with JUnit Test annotation?

I like user64141's answer but found that it could be more generalized. Here's my take:

public abstract class ExpectedThrowableAsserter implements Runnable {

    private final Class<? extends Throwable> throwableClass;
    private final String expectedExceptionMessage;

    protected ExpectedThrowableAsserter(Class<? extends Throwable> throwableClass, String expectedExceptionMessage) {
        this.throwableClass = throwableClass;
        this.expectedExceptionMessage = expectedExceptionMessage;
    }

    public final void run() {
        try {
            expectException();
        } catch (Throwable e) {
            assertTrue(String.format("Caught unexpected %s", e.getClass().getSimpleName()), throwableClass.isInstance(e));
            assertEquals(String.format("%s caught, but unexpected message", throwableClass.getSimpleName()), expectedExceptionMessage, e.getMessage());
            return;
        }
        fail(String.format("Expected %s, but no exception was thrown.", throwableClass.getSimpleName()));
    }

    protected abstract void expectException();

}

Note that leaving the "fail" statement within the try block causes the related assertion exception to be caught; using return within the catch statement prevents this.

maximum value of int

What about (1 << (8*sizeof(int)-2)) - 1 + (1 << (8*sizeof(int)-2)). This is the same as 2^(8*sizeof(int)-2) - 1 + 2^(8*sizeof(int)-2).

If sizeof(int) = 4 => 2^(8*4-2) - 1 + 2^(8*4-2) = 2^30 - 1 + 20^30 = (2^32)/2 - 1 [max signed int of 4 bytes].

You can't use 2*(1 << (8*sizeof(int)-2)) - 1 because it will overflow, but (1 << (8*sizeof(int)-2)) - 1 + (1 << (8*sizeof(int)-2)) works.

How to reset a form using jQuery with .reset() method

Here is simple solution with Jquery. It works globally. Have a look on the code.

$('document').on("click", ".clear", function(){
   $(this).closest('form').trigger("reset");
})

Add a clear class to a button in every form you need to reset it. For example:

<button class="button clear" type="reset">Clear</button>

What does "pending" mean for request in Chrome Developer Window?

I had a similar issue with application/json ajax calls. In ff/IE they were fine. In chrome in the Developer Network window Status was always (pending) because a different status code was being returned.

In my case I changed my Json response to send a HttpStatusCode of 200 then Chrome was fine and the Status Text changed to 200 OK.

For example using ASP.NET Web Api

 return new HttpResponseMessage(HttpStatusCode.OK ) {
            Content = request.Content
        };

No Activity found to handle Intent : android.intent.action.VIEW

First try this code inside AndroidManifest

  <application>
       
    <uses-library
        android:name="org.apache.http.legacy"
        android:required="false" />
 </application>

If this code works, so fine. But if not. Try this code from which class you want to pass the data or uri.

Intent window = new Intent(getApplicationContext(), Browser.class);
window.putExtra("LINK", "http://www.yourwebsite.com");
startActivity(window);

Does Java have a path joining method?

Try:

String path1 = "path1";
String path2 = "path2";

String joinedPath = new File(path1, path2).toString();

Enable/Disable Anchor Tags using AngularJS

My problem was slightly different: I have anchor tags that define an href, and I want to use ng-disabled to prevent the link from going anywhere when clicked. The solution is to un-set the href when the link is disabled, like this:

<a ng-href="{{isDisabled ? '' : '#/foo'}}"
   ng-disabled="isDisabled">Foo</a>

In this case, ng-disabled is only used for styling the element.

If you want to avoid using unofficial attributes, you'll need to style it yourself:

<style>
a.disabled {
    color: #888;
}
</style>
<a ng-href="{{isDisabled ? '' : '#/foo'}}"
   ng-class="{disabled: isDisabled}">Foo</a>

how to remove untracked files in Git?

Well, I had the similar issue. I had taken latest but there were some changes in the local due to which the merge was not happening to a particular file. The file was untracked and I did not want them so What I did was -

$ git checkout filepath/filename

filepath - The location from where I did the git bash. then when I took the latest the changes were available