How can I create a memory leak in Java?

I don't think anyone has said this yet: you can resurrect an object by overriding the finalize() method such that finalize() stores a reference of this somewhere. The garbage collector will only be called once on the object so after that the object will never destroyed.

How can I upload files asynchronously?

For PHP, look for https://developer.hyvor.com/php/image-upload-ajax-php-mysql

HTML

<html>
<head>
    <title>Image Upload with AJAX, PHP and MYSQL</title>
</head>
<body>
<form onsubmit="submitForm(event);">
    <input type="file" name="image" id="image-selecter" accept="image/*">
    <input type="submit" name="submit" value="Upload Image">
</form>
<div id="uploading-text" style="display:none;">Uploading...</div>
<img id="preview">
</body>
</html>

JAVASCRIPT

var previewImage = document.getElementById("preview"),  
    uploadingText = document.getElementById("uploading-text");

function submitForm(event) {
    // prevent default form submission
    event.preventDefault();
    uploadImage();
}

function uploadImage() {
    var imageSelecter = document.getElementById("image-selecter"),
        file = imageSelecter.files[0];
    if (!file) 
        return alert("Please select a file");
    // clear the previous image
    previewImage.removeAttribute("src");
    // show uploading text
    uploadingText.style.display = "block";
    // create form data and append the file
    var formData = new FormData();
    formData.append("image", file);
    // do the ajax part
    var ajax = new XMLHttpRequest();
    ajax.onreadystatechange = function() {
        if (this.readyState === 4 && this.status === 200) {
            var json = JSON.parse(this.responseText);
            if (!json || json.status !== true) 
                return uploadError(json.error);

            showImage(json.url);
        }
    }
    ajax.open("POST", "upload.php", true);
    ajax.send(formData); // send the form data
}

PHP

<?php
$host = 'localhost';
$user = 'user';
$password = 'password';
$database = 'database';
$mysqli = new mysqli($host, $user, $password, $database);


 try {
    if (empty($_FILES['image'])) {
        throw new Exception('Image file is missing');
    }
    $image = $_FILES['image'];
    // check INI error
    if ($image['error'] !== 0) {
        if ($image['error'] === 1) 
            throw new Exception('Max upload size exceeded');

        throw new Exception('Image uploading error: INI Error');
    }
    // check if the file exists
    if (!file_exists($image['tmp_name']))
        throw new Exception('Image file is missing in the server');
    $maxFileSize = 2 * 10e6; // in bytes
    if ($image['size'] > $maxFileSize)
        throw new Exception('Max size limit exceeded'); 
    // check if uploaded file is an image
    $imageData = getimagesize($image['tmp_name']);
    if (!$imageData) 
        throw new Exception('Invalid image');
    $mimeType = $imageData['mime'];
    // validate mime type
    $allowedMimeTypes = ['image/jpeg', 'image/png', 'image/gif'];
    if (!in_array($mimeType, $allowedMimeTypes)) 
        throw new Exception('Only JPEG, PNG and GIFs are allowed');

    // nice! it's a valid image
    // get file extension (ex: jpg, png) not (.jpg)
    $fileExtention = strtolower(pathinfo($image['name'] ,PATHINFO_EXTENSION));
    // create random name for your image
    $fileName = round(microtime(true)) . mt_rand() . '.' . $fileExtention; // anyfilename.jpg
    // Create the path starting from DOCUMENT ROOT of your website
    $path = '/examples/image-upload/images/' . $fileName;
    // file path in the computer - where to save it 
    $destination = $_SERVER['DOCUMENT_ROOT'] . $path;

    if (!move_uploaded_file($image['tmp_name'], $destination))
        throw new Exception('Error in moving the uploaded file');

    // create the url
    $protocol = stripos($_SERVER['SERVER_PROTOCOL'],'https') === true ? 'https://' : 'http://';
    $domain = $protocol . $_SERVER['SERVER_NAME'];
    $url = $domain . $path;
    $stmt = $mysqli -> prepare('INSERT INTO image_uploads (url) VALUES (?)');
    if (
        $stmt &&
        $stmt -> bind_param('s', $url) &&
        $stmt -> execute()
    ) {
        exit(
            json_encode(
                array(
                    'status' => true,
                    'url' => $url
                )
            )
        );
    } else 
        throw new Exception('Error in saving into the database');

} catch (Exception $e) {
    exit(json_encode(
        array (
            'status' => false,
            'error' => $e -> getMessage()
        )
    ));
}

Memory errors and list limits?

If you want to circumvent this problem you could also use the shelve. Then you would create files that would be the size of your machines capacity to handle, and only put them on the RAM when necessary, basically writing to the HD and pulling the information back in pieces so you can process it.

Create binary file and check if information is already in it if yes make a local variable to hold it else write some data you deem necessary.

Data = shelve.open('File01')
   for i in range(0,100):
     Matrix_Shelve = 'Matrix' + str(i)
     if Matrix_Shelve in Data:
        Matrix_local = Data[Matrix_Shelve]
     else:
        Data[Matrix_Selve] = 'somenthingforlater'

Hope it doesn't sound too arcaic.

What is difference between @RequestBody and @RequestParam?

@RequestParam annotated parameters get linked to specific Servlet request parameters. Parameter values are converted to the declared method argument type. This annotation indicates that a method parameter should be bound to a web request parameter.

For example Angular request for Spring RequestParam(s) would look like that:

$http.post('http://localhost:7777/scan/l/register?username="Johny"&password="123123"&auth=true')
      .success(function (data, status, headers, config) {
                        ...
                    })

Endpoint with RequestParam:

@RequestMapping(method = RequestMethod.POST, value = "/register")
public Map<String, String> register(Model uiModel,
                                    @RequestParam String username,
                                    @RequestParam String password,
                                    @RequestParam boolean auth,
                                    HttpServletRequest httpServletRequest) {...

@RequestBody annotated parameters get linked to the HTTP request body. Parameter values are converted to the declared method argument type using HttpMessageConverters. This annotation indicates a method parameter should be bound to the body of the web request.

For example Angular request for Spring RequestBody would look like that:

$scope.user = {
            username: "foo",
            auth: true,
            password: "bar"
        };    
$http.post('http://localhost:7777/scan/l/register', $scope.user).
                        success(function (data, status, headers, config) {
                            ...
                        })

Endpoint with RequestBody:

@RequestMapping(method = RequestMethod.POST, produces = "application/json", 
                value = "/register")
public Map<String, String> register(Model uiModel,
                                    @RequestBody User user,
                                    HttpServletRequest httpServletRequest) {...

Hope this helps.

Save range to variable

My use case was to save range to variable and then select it later on

Dim targetRange As Range
Set targetRange = Sheets("Sheet").Range("Name")
Application.Goto targetRange
Set targetRangeQ = Nothing ' reset

CSV API for Java

The CSV format sounds easy enough for StringTokenizer but it can become more complicated. Here in Germany a semicolon is used as a delimiter and cells containing delimiters need to be escaped. You're not going to handle that easily with StringTokenizer.

I would go for http://sourceforge.net/projects/javacsv

Best method for reading newline delimited files and discarding the newlines?

I'd do it like this:

f = open('test.txt')
l = [l for l in f.readlines() if l.strip()]
f.close()
print l

Showing all errors and warnings

Display errors could be turned off in the php.ini or your Apache configuration file.

You can turn it on in the script:

error_reporting(E_ALL);
ini_set('display_errors', '1');

You should see the same messages in the PHP error log.

Java Project: Failed to load ApplicationContext

I had the same problem, and I was using the following plugin for tests:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.9</version>
    <configuration>
        <useFile>true</useFile>
        <includes>
            <include>**/*Tests.java</include>
            <include>**/*Test.java</include>
        </includes>
        <excludes>
            <exclude>**/Abstract*.java</exclude>
        </excludes>
        <junitArtifactName>junit:junit</junitArtifactName>
        <parallel>methods</parallel>
        <threadCount>10</threadCount>
    </configuration>
</plugin>

The test were running fine in the IDE (eclipse sts), but failed when using command mvn test.

After a lot of trial and error, I figured the solution was to remove parallel testing, the following two lines from the plugin configuration above:

    <parallel>methods</parallel>
    <threadCount>10</threadCount>

Hope that this helps someone out!

Cannot Resolve Collation Conflict

The thing about collations is that although the database has its own collation, every table, and every column can have its own collation. If not specified it takes the default of its parent object, but can be different.

When you change collation of the database, it will be the new default for all new tables and columns, but it doesn't change the collation of existing objects inside the database. You have to go and change manually the collation of every table and column.

Luckily there are scripts available on the internet that can do the job. I am not going to recommend any as I haven't tried them but here are few links:

http://www.codeproject.com/Articles/302405/The-Easy-way-of-changing-Collation-of-all-Database

Update Collation of all fields in database on the fly

http://www.sqlservercentral.com/Forums/Topic820675-146-1.aspx

If you need to have different collation on two objects or can't change collations - you can still JOIN between them using COLLATE command, and choosing the collation you want for join.

SELECT * FROM A JOIN B ON A.Text = B.Text COLLATE Latin1_General_CI_AS

or using default database collation:

SELECT * FROM A JOIN B ON A.Text = B.Text COLLATE DATABASE_DEFAULT

How to include JavaScript file or library in Chrome console?

In the modern browsers you can use the fetch to download resource (Mozilla docs) and then eval to execute it.

For example to download Angular1 you need to type:

fetch('https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.8/angular.min.js')
    .then(response => response.text())
    .then(text => eval(text))
    .then(() => { /* now you can use your library */ })

How can I make a JUnit test wait?

Thread.sleep() could work in most cases, but usually if you're waiting, you are actually waiting for a particular condition or state to occur. Thread.sleep() does not guarantee that whatever you're waiting for has actually happened.

If you are waiting on a rest request for example maybe it usually return in 5 seconds, but if you set your sleep for 5 seconds the day your request comes back in 10 seconds your test is going to fail.

To remedy this JayWay has a great utility called Awatility which is perfect for ensuring that a specific condition occurs before you move on.

It has a nice fluent api as well

await().until(() -> 
{
    return yourConditionIsMet();
});

https://github.com/jayway/awaitility

How to find a Java Memory Leak

I use following approach to finding memory leaks in Java. I've used jProfiler with great success, but I believe that any specialized tool with graphing capabilities (diffs are easier to analyze in graphical form) will work.

Start the application and wait until it get to "stable" state, when all the initialization is complete and the application is idle.
Run the operation suspected of producing a memory leak several times to allow any cache, DB-related initialization to take place.
Run GC and take memory snapshot.
Run the operation again. Depending on the complexity of operation and sizes of data that is processed operation may need to be run several to many times.
Run GC and take memory snapshot.
Run a diff for 2 snapshots and analyze it.

Basically analysis should start from greatest positive diff by, say, object types and find what causes those extra objects to stick in memory.

For web applications that process requests in several threads analysis gets more complicated, but nevertheless general approach still applies.

I did quite a number of projects specifically aimed at reducing memory footprint of the applications and this general approach with some application specific tweaks and trick always worked well.

Can two Java methods have same name with different return types?

Only if their parameter declarations are different from memory.

How to close a thread from within?

A little late, but I use a _is_running variable to tell the thread when I want to close. It's easy to use, just implement a stop() inside your thread class.

def stop(self):
  self._is_running = False

And in run() just loop on while(self._is_running)

What is the difference between smoke testing and sanity testing?

THERE IS NO DIFFERENCE BETWEEN smoke and sanity as per ISTQB.

sanity is synonym of smoke.

Check it here : https://glossary.istqb.org/en/search/sanity

How to round up a number to nearest 10?

I wanted to round up to the next number in the largest digits place (is there a name for that?), so I made the following function (in php):

//Get the max value to use in a graph scale axis, 
//given the max value in the graph
function getMaxScale($maxVal) {
    $maxInt = ceil($maxVal);
    $numDigits = strlen((string)$maxInt)-1; //this makes 2150->3000 instead of 10000
    $dividend = pow(10,$numDigits);
    $maxScale= ceil($maxInt/ $dividend) * $dividend;
    return $maxScale;
}

How to add Button over image using CSS?

Adapt this example to your code

HTML

<div class="img-holder">
    <img src="images/img-1.png" alt="image description"/>
    <a class="link" href=""></a>
</div>

CSS

.img-holder {position: relative;}
.img-holder .link {
    position: absolute;
    bottom: 10px; /*your button position*/
    right: 10px; /*your button position*/
}

How to use jQuery in AngularJS

This should be working. Please have a look at this fiddle.

$(function() {
   $( "#slider" ).slider();
});//Links to jsfiddle must be accompanied by code

Make sure you're loading the libraries in this order: jQuery, jQuery UI CSS, jQuery UI, AngularJS.

How to pass parameters on onChange of html select

_x000D_

function getComboA(selectObject) {_x000D_
  var value = selectObject.value;  _x000D_
  console.log(value);_x000D_
}

_x000D_

<select id="comboA" onchange="getComboA(this)">_x000D_
  <option value="">Select combo</option>_x000D_
  <option value="Value1">Text1</option>_x000D_
  <option value="Value2">Text2</option>_x000D_
  <option value="Value3">Text3</option>_x000D_
</select>

_x000D_

The above example gets you the selected value of combo box on OnChange event.

Editing dictionary values in a foreach loop

Along with the other answers, I thought I'd note that if you get sortedDictionary.Keys or sortedDictionary.Values and then loop over them with foreach, you also go through in sorted order. This is because those methods return System.Collections.Generic.SortedDictionary<TKey,TValue>.KeyCollection or SortedDictionary<TKey,TValue>.ValueCollection objects, which maintain the sort of the original dictionary.

array_push() with key value pair

So what about having:

$data['cat']='wagon';

Java URLConnection Timeout

Try this:

       import java.net.HttpURLConnection;

       URL url = new URL("http://www.myurl.com/sample.xml");

       HttpURLConnection huc = (HttpURLConnection) url.openConnection();
       HttpURLConnection.setFollowRedirects(false);
       huc.setConnectTimeout(15 * 1000);
       huc.setRequestMethod("GET");
       huc.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)");
       huc.connect();
       InputStream input = huc.getInputStream();

OR

       import org.jsoup.nodes.Document;

       Document doc = null;
       try {
           doc = Jsoup.connect("http://www.myurl.com/sample.xml").get();
       } catch (Exception e) {
           //log error
       }

And take look on how to use Jsoup: http://jsoup.org/cookbook/input/load-document-from-url

jQuery select option elements by value

You can use .val() to select the value, like the following:

function select_option(i) {
    $("#span_id select").val(i);
}

Here is a jsfiddle: https://jsfiddle.net/tweissin/uscq42xh/8/

An unhandled exception of type 'System.IO.FileNotFoundException' occurred in Unknown Module

Enable this option in VS: Just My Code option

Tools -> Options -> Debugging -> General -> Enable Just My Code (Managed only)

How to fix a collation conflict in a SQL Server query?

I resolved a similar issue by wrapping the query in another query...

Initial query was working find giving individual columns of output, with some of the columns coming from sub queries with Max or Sum function, and other with "distinct" or case substitutions and such.

I encountered the collation error after attempting to create a single field of output with...

select
rtrim(field1)+','+rtrim(field2)+','+...

The query would execute as I wrote it, but the error would occur after saving the sql and reloading it.

Wound up fixing it with something like...

select z.field1+','+z.field2+','+... as OUTPUT_REC
from (select rtrim(field1), rtrim(field2), ... ) z

Some fields are "max" of a subquery, with a case substitution if null and others are date fields, and some are left joins (might be NULL)...in other words, mixed field types. I believe this is the cause of the issue being caused by OS collation and Database collation being slightly different, but by converting all to trimmed strings before the final select, it sorts it out, all in the SQL.

How can I process each letter of text using Javascript?

When I need to write short code or a one-liner, I use this "hack":

'Hello World'.replace(/./g, function (char) {
    alert(char);
    return char; // this is optional 
});

This won't count newlines so that can be a good thing or a bad thing. If you which to include newlines, replace: /./ with /[\S\s]/. The other one-liners you may see probably use .split() which has many problems

Angular2 If ngModel is used within a form tag, either the name attribute must be set or the form

For me, the solution was very simple. I changed the <form> tag into a <div> and the error goes away.

Display A Popup Only Once Per User

The code to show only one time the popup (Bootstrap Modal in the case) :

modal.js

 $(document).ready(function() {
     if (Cookies('pop') == null) {
         $('#ModalIdName').modal('show');
         Cookies('pop', '365');
     }
 });

Here is the full code snipet for Rails :

Add the script above to your js repo (in Rails : app/javascript/packs)

In Rails we have a specific packing way for script, so :

Download the js-cookie plugin (needed to work with Javascript Cokkies) https://github.com/js-cookie/js-cookie (the name should be : 'js.cookie.js')

/*!
 * JavaScript Cookie v2.2.0
 * https://github.com/js-cookie/js-cookie
 *
 * Copyright 2006, 2015 Klaus Hartl & Fagner Brack
 * Released under the MIT license
 */
;(function (factory) {
  var registeredInModuleLoader = false;
  if (typeof define === 'function' && define.amd) {
    define(factory);
    registeredInModul
 ...

Add //= require js.cookie to application.js

It will works perfectly for 365 days!

How to trigger a phone call when clicking a link in a web page on mobile phone

The proper URL scheme is tel:[number] so you would do

_x000D_

<a href="tel:5551234567"><img src="callme.jpg" /></a>

_x000D_

data.table vs dplyr: can one do something well the other can't or does poorly?

Reading Hadley and Arun's answers one gets the impression that those who prefer dplyr's syntax would have in some cases to switch over to data.table or compromise for long running times.

But as some have already mentioned, dplyr can use data.table as a backend. This is accomplished using the dtplyr package which recently had it's version 1.0.0 release. Learning dtplyr incurs practically zero additional effort.

When using dtplyr one uses the function lazy_dt() to declare a lazy data.table, after which standard dplyr syntax is used to specify operations on it. This would look something like the following:

new_table <- mtcars2 %>% 
  lazy_dt() %>%
  filter(wt < 5) %>% 
  mutate(l100k = 235.21 / mpg) %>% # liters / 100 km
  group_by(cyl) %>% 
  summarise(l100k = mean(l100k))

  new_table

#> Source: local data table [?? x 2]
#> Call:   `_DT1`[wt < 5][, `:=`(l100k = 235.21/mpg)][, .(l100k = mean(l100k)), 
#>     keyby = .(cyl)]
#> 
#>     cyl l100k
#>   <dbl> <dbl>
#> 1     4  9.05
#> 2     6 12.0 
#> 3     8 14.9 
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results

The new_table object is not evaluated until calling on it as.data.table()/as.data.frame()/as_tibble() at which point the underlying data.table operation is executed.

I've recreated a benchmark analysis done by data.table author Matt Dowle back at December 2018 which covers the case of operations over large numbers of groups. I've found that dtplyr indeed enables for the most part those who prefer the dplyr syntax to keep using it while enjoying the speed offered by data.table.

anaconda - graphviz - can't import after installation

For ubuntu users I recommend this way:

sudo apt-get install -y graphviz libgraphviz-dev

Change package name for Android in React Native

The simplest one:

npx react-native-rename YourNewAppName -b com.YourCompanyName.YourNewAppName

current/duration time of html5 video?

I am assuming you want to display this as part of the player.

This site breaks down how to get both the current and total time regardless of how you want to display it though using jQuery:

http://dev.opera.com/articles/view/custom-html5-video-player-with-css3-and-jquery/

This will also cover how to set it to a specific div. As philip has already mentioned, .currentTime will give you where you are in the video.

CSS transition fade in

I believe you could addClass to the element. But either way you'd have to use Jquery or reg JS

div {
  opacity:0;
  transition:opacity 1s linear;*
}
div.SomeClass {
  opacity:1;
}

Where does SVN client store user authentication data?

On Windows, you can find it under.

%USERPROFILE%\AppData\Roaming\Subversion\auth\svn.simple
(same as below)
%APPDATA%\Roaming\Subversion\auth\svn.simple

There may be multiple files under this directory, depending upon the repos you are contributing to. You can assume this as one file for each svn server. You can open the file with any text editor and make sure you are going to delete the correct file.

Linux: Which process is causing "device busy" when doing umount?

Filesystems mounted on the filesystem you're trying to unmount can cause the target is busy error in addition to any files that are in use. (For example when you mount -o bind /dev /mnt/yourmount/dev in order to use chroot there.)

To find which file systems are mounted on the filesystem run the following:

mount | grep '/mnt/yourmount'

To find which files are in use the advice already suggested by others here:

lsof | grep '/mnt/yourmount'

What is the difference between parseInt() and Number()?

I always use parseInt, but beware of leading zeroes that will force it into octal mode.

Running JAR file on Windows

Besides all of the other suggestions, there is one other thing you need to consider. Is your helloworld.jar a console program? If it is, then I don't believe you'll be able to make it into a double-clickable jar file. Console programs use the regular cmd.exe shell window for their input and output. Usually the jar "launcher" is bound to javaw.exe which doesn't create a command-shell window.

Check date between two other dates spring data jpa

You should take a look the reference documentation. It's well explained.

In your case, I think you cannot use between because you need to pass two parameters

Between - findByStartDateBetween … where x.startDate between ?1 and ?2

In your case take a look to use a combination of LessThan or LessThanEqual with GreaterThan or GreaterThanEqual

LessThan/LessThanEqual

LessThan - findByEndLessThan … where x.start< ?1

LessThanEqual findByEndLessThanEqual … where x.start <= ?1

GreaterThan/GreaterThanEqual

GreaterThan - findByStartGreaterThan … where x.end> ?1

GreaterThanEqual - findByStartGreaterThanEqual … where x.end>= ?1

You can use the operator And and Or to combine both.

How to parse XML to R data frame

Data in XML format are rarely organized in a way that would allow the xmlToDataFrame function to work. You're better off extracting everything in lists and then binding the lists together in a data frame:

require(XML)
data <- xmlParse("http://forecast.weather.gov/MapClick.php?lat=29.803&lon=-82.411&FcstType=digitalDWML")

xml_data <- xmlToList(data)

In the case of your example data, getting location and start time is fairly straightforward:

location <- as.list(xml_data[["data"]][["location"]][["point"]])

start_time <- unlist(xml_data[["data"]][["time-layout"]][
    names(xml_data[["data"]][["time-layout"]]) == "start-valid-time"])

Temperature data is a bit more complicated. First you need to get to the node that contains the temperature lists. Then you need extract both the lists, look within each one, and pick the one that has "hourly" as one of its values. Then you need to select only that list but only keep the values that have the "value" label:

temps <- xml_data[["data"]][["parameters"]]
temps <- temps[names(temps) == "temperature"]
temps <- temps[sapply(temps, function(x) any(unlist(x) == "hourly"))]
temps <- unlist(temps[[1]][sapply(temps, names) == "value"])

out <- data.frame(
  as.list(location),
  "start_valid_time" = start_time,
  "hourly_temperature" = temps)

head(out)
  latitude longitude          start_valid_time hourly_temperature
1    29.81    -82.42 2013-06-19T16:00:00-04:00                 91
2    29.81    -82.42 2013-06-19T17:00:00-04:00                 90
3    29.81    -82.42 2013-06-19T18:00:00-04:00                 89
4    29.81    -82.42 2013-06-19T19:00:00-04:00                 85
5    29.81    -82.42 2013-06-19T20:00:00-04:00                 83
6    29.81    -82.42 2013-06-19T21:00:00-04:00                 80

How should a model be structured in MVC?

In my case I have a database class that handle all the direct database interaction such as querying, fetching, and such. So if I had to change my database from MySQL to PostgreSQL there won't be any problem. So adding that extra layer can be useful.

Each table can have its own class and have its specific methods, but to actually get the data, it lets the database class handle it:

File `Database.php`

class Database {
    private static $connection;
    private static $current_query;
    ...

    public static function query($sql) {
        if (!self::$connection){
            self::open_connection();
        }
        self::$current_query = $sql;
        $result = mysql_query($sql,self::$connection);

        if (!$result){
            self::close_connection();
            // throw custom error
            // The query failed for some reason. here is query :: self::$current_query
            $error = new Error(2,"There is an Error in the query.\n<b>Query:</b>\n{$sql}\n");
            $error->handleError();
        }
        return $result;
    }
 ....

    public static function find_by_sql($sql){
        if (!is_string($sql))
            return false;

        $result_set = self::query($sql);
        $obj_arr = array();
        while ($row = self::fetch_array($result_set))
        {
            $obj_arr[] = self::instantiate($row);
        }
        return $obj_arr;
    }
}

Table object classL

class DomainPeer extends Database {

    public static function getDomainInfoList() {
        $sql = 'SELECT ';
        $sql .='d.`id`,';
        $sql .='d.`name`,';
        $sql .='d.`shortName`,';
        $sql .='d.`created_at`,';
        $sql .='d.`updated_at`,';
        $sql .='count(q.id) as queries ';
        $sql .='FROM `domains` d ';
        $sql .='LEFT JOIN queries q on q.domainId = d.id ';
        $sql .='GROUP BY d.id';
        return self::find_by_sql($sql);
    }

    ....
}

I hope this example helps you create a good structure.

How to limit depth for recursive file list?

Checkout the -maxdepth flag of find

find . -maxdepth 1 -type d -exec ls -ld "{}" \;

Here I used 1 as max level depth, -type d means find only directories, which then ls -ld lists contents of, in long format.

turn typescript object into json string

If you're using fs-extra, you can skip the JSON.stringify part with the writeJson function:

const fsExtra = require('fs-extra');

fsExtra.writeJson('./package.json', {name: 'fs-extra'})
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

How to terminate script execution when debugging in Google Chrome?

There are many appropiate solution to this problem as mentioned above in this post, but i have found a small hack that can be inserrted in the script or pasted in the Chromes console (debugger) to achieve it:

jQuery(window).keydown(function(e) { if (e.keyCode == 123) debugger; });

This will cause execution to be paused when you hit F12.

Can I use Twitter Bootstrap and jQuery UI at the same time?

Although this question specifically mentions jQuery-UI autosuggest feature, the question title is more general: does bootstrap 3 work with jQuery UI? I was having trouble with the jQUI datepicker (pop-up calendar) feature. I solved the datepicker problem and hope the solution will help with other jQUI/BS issues.

I had a difficult time today getting the latest jQueryUI (ver 1.12.1) datepicker to work with bootstrap 3.3.7. What was happening is that the calendar would display but it would not close.

Turned out to be a version problem with jQUI and BS. I was using the latest version of Bootstrap, and found that I had to downgrade to these versions of jQUI and jQuery:

jQueryUI - 1.9.2 (tested - works)
jQuery - 1.9.1 or 2.1.4 (tested - both work. Other vers may work, but these work.)
Bootstrap 3.3.7 (tested - works)

Because I wanted to use a custom theme, I also built a custom download of jQUI (removed a few things like all the interactions, dialog, progressbar and a few effects I don't use) -- and made sure to select "Cupertino" at the bottom as my theme.

I installed them thus:

<head>
...etc...
<link rel="stylesheet" href="css/font-awesome.min.css">
<link rel="stylesheet" href="css/cupertino/jquery-ui-1.9.2.custom.min.css">
<link rel="stylesheet" href="css/bootstrap-3.3.7.min.css">

<!-- <script src="js/jquery-1.9.1.min.js"></script> -->
<script src="js/jquery-2.1.4.min.js"></script>
<script src="js/jquery-ui-1.9.2.custom.min.js"></script>
<script src="js/bootstrap-3.3.7.min.js"></script>
...etc...
</head>

For those interested, the CSS folder looks like this:

[css]
  - bootstrap-3.3.7.min.css
  - font-awesome.min.css
  - style.css
  - [cupertino]
      - jquery-ui-1.9.2.custom.min.css
      [images]
          - ui-bg_diagonals-thick_90_eeeeee_40x40.png
          - ui-bg_glass_100_e4f1fb_1x400.png
          - ui-bg_glass_50_3baae3_1x400.png
          - ui-bg_glass_80_d7ebf9_1x400.png
          - ui-bg_highlight-hard_100_f2f5f7_1x100.png
          - etc (8 more files that were in the downloaded jQUI zip file)

Adding newline characters to unix shell variables

How to place two forms on the same page?

You could make two forms with 2 different actions

<form action="login.php" method="post">
    <input type="text" name="user">
    <input type="password" name="password">
    <input type="submit" value="Login">
</form>

<br />

<form action="register.php" method="post">
    <input type="text" name="user">
    <input type="password" name="password">
    <input type="submit" value="Register">
</form>

Or do this

<form action="doStuff.php" method="post">
    <input type="text" name="user">
    <input type="password" name="password">
    <input type="hidden" name="action" value="login">
    <input type="submit" value="Login">
</form>

<br />

<form action="doStuff.php" method="post">
    <input type="text" name="user">
    <input type="password" name="password">
    <input type="hidden" name="action" value="register">
    <input type="submit" value="Register">
</form>

Then you PHP file would work as a switch($_POST['action']) ... furthermore, they can't click on both links at the same time or make a simultaneous request, each submit is a separate request.

Your PHP would then go on with the switch logic or have different php files doing a login procedure then a registration procedure

Improving bulk insert performance in Entity framework

Currently there is no better way, however there may be a marginal improvement by moving SaveChanges inside for loop for probably 10 items.

int i = 0;

foreach (Employees item in sequence)
{
   t = new Employees ();
   t.Text = item.Text;
   dataContext.Employees.AddObject(t);   

   // this will add max 10 items together
   if((i % 10) == 0){
       dataContext.SaveChanges();
       // show some progress to user based on
       // value of i
   }
   i++;
}
dataContext.SaveChanges();

You can adjust 10 to be closer to better performance. It will not greatly improve speed but it will allow you to show some progress to user and make it more user friendly.

java.lang.ClassNotFoundException: HttpServletRequest

I had the same problem, and the cause was the missing of commons-logging-1.2.jar

I add it to the lib folder, then my Apache Tomcat 7 server executed without problems.

What is pluginManagement in Maven's pom.xml?

You still need to add

<plugins>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
    </plugin>
</plugins>

in your build, because pluginManagement is only a way to share the same plugin configuration across all your project modules.

From Maven documentation:

pluginManagement: is an element that is seen along side plugins. Plugin Management contains plugin elements in much the same way, except that rather than configuring plugin information for this particular project build, it is intended to configure project builds that inherit from this one. However, this only configures plugins that are actually referenced within the plugins element in the children. The children have every right to override pluginManagement definitions.

How to do integer division in javascript (Getting division answer in int not float)?

var x = parseInt(455/10);

The parseInt() function parses a string and returns an integer.

The radix parameter is used to specify which numeral system to be used, for example, a radix of 16 (hexadecimal) indicates that the number in the string should be parsed from a hexadecimal number to a decimal number.

If the radix parameter is omitted, JavaScript assumes the following:
If the string begins with "0x", the radix is 16 (hexadecimal)
If the string begins with "0", the radix is 8 (octal). This feature is deprecated
If the string begins with any other value, the radix is 10 (decimal)

How to get the type of a variable in MATLAB?

Another related function is whos. It will list all sorts of information (dimensions, byte size, type) for the variables in a given workspace.

>> a = [0 0 7];
>> whos a
  Name      Size            Bytes  Class     Attributes

  a         1x3                24  double              

>> b = 'James Bond';
>> whos b
  Name      Size            Bytes  Class    Attributes

  b         1x10               20  char

Checkbox angular material checked by default

// in component.ts
checked: boolean = true;
indeterminate:boolean = false;
disabled:boolean = false;
label:string;

onCheck() {
    this.label = this.checked?'ON':'OFF';
}

// in component.html`enter code here`
<mat-checkbox class="example-margin" [color]="primary" [(ngModel)]="checked" [(indeterminate)]="indeterminate" [labelPosition]="after" [disabled]="disabled" (change)="onCheck()">
                    {{label}}
                  </mat-checkbox>

The above code should work fine. Mat checkbox allows you to make it checked/unchecked, disabled, set indeterminate state, do some operation onChange of the state etc. Refer API for more details.

Why is there extra padding at the top of my UITableView with style UITableViewStyleGrouped in iOS7

use this one i think this help...

 - (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
 {
    return 0.005f;// set this according to that you want...
 }

Passing variables through handlebars partial

This is very possible if you write your own helper. We are using a custom $ helper to accomplish this type of interaction (and more):

/*///////////////////////

Adds support for passing arguments to partials. Arguments are merged with 
the context for rendering only (non destructive). Use `:token` syntax to 
replace parts of the template path. Tokens are replace in order.

USAGE: {{$ 'path.to.partial' context=newContext foo='bar' }}
USAGE: {{$ 'path.:1.:2' replaceOne replaceTwo foo='bar' }}

///////////////////////////////*/

Handlebars.registerHelper('$', function(partial) {
    var values, opts, done, value, context;
    if (!partial) {
        console.error('No partial name given.');
    }
    values = Array.prototype.slice.call(arguments, 1);
    opts = values.pop();
    while (!done) {
        value = values.pop();
        if (value) {
            partial = partial.replace(/:[^\.]+/, value);
        }
        else {
            done = true;
        }
    }
    partial = Handlebars.partials[partial];
    if (!partial) {
        return '';
    }
    context = _.extend({}, opts.context||this, _.omit(opts, 'context', 'fn', 'inverse'));
    return new Handlebars.SafeString( partial(context) );
});

Select first and last row from grouped data

Another approach with lapply and a dplyr statement. We can apply an arbitrary number of whatever summary functions to the same statement:

lapply(c(first, last), 
       function(x) df %>% group_by(id) %>% summarize_all(funs(x))) %>% 
bind_rows()

You could for example be interested in rows with the max stopSequence value as well and do:

lapply(c(first, last, max("stopSequence")), 
       function(x) df %>% group_by(id) %>% summarize_all(funs(x))) %>%
bind_rows()

What is the "Temporary ASP.NET Files" folder for?

These are what's known as Shadow Copy Folders.

Simplistically....and I really mean it:

When ASP.NET runs your app for the first time, it copies any assemblies found in the /bin folder, copies any source code files (found for example in the App_Code folder) and parses your aspx, ascx files to c# source files. ASP.NET then builds/compiles all this code into a runnable application.

One advantage of doing this is that it prevents the possibility of .NET assembly DLL's #(in the /bin folder) becoming locked by the ASP.NET worker process and thus not updatable.

ASP.NET watches for file changes in your website and will if necessary begin the whole process all over again.

Theoretically the folder shouldn't need any maintenance, but from time to time, and only very rarely you may need to delete contents. That said, I work for a hosting company, we run up to 1200 sites per shared server and I haven't had to touch this folder on any of the 250 or so machines for years.

This is outlined in the MSDN article Understanding ASP.NET Dynamic Compilation

How to permanently set $PATH on Linux/Unix?

I think the most elegant way is:

1.add this in ~/.bashrc file Run this command

gedit ~/.bashrc

add your path inside it

export PATH=$PATH:/opt/node/bin

2.source ~/.bashrc

(Ubuntu)

what is .subscribe in angular?

In Angular (currently on Angular-6) .subscribe() is a method on the Observable type. The Observable type is a utility that asynchronously or synchronously streams data to a variety of components or services that have subscribed to the observable.

The observable is an implementation/abstraction over the promise chain and will be a part of ES7 as a proposed and very supported feature. In Angular it is used internally due to rxjs being a development dependency.

An observable itself can be thought of as a stream of data coming from a source, in Angular this source is an API-endpoint, a service, a database or another observable. But the power it has is that it's not expecting a single response. It can have one or many values that are returned.

Link to rxjs for observable/subscribe docs here: https://rxjs-dev.firebaseapp.com/api/index/class/Observable#subscribe-

Subscribe takes 3 methods as parameters each are functions:

next: For each item being emitted by the observable perform this function
error: If somewhere in the stream an error is found, do this method
complete: Once all items are complete from the stream, do this method

Within each of these, there is the potentional to pipe (or chain) other utilities called operators onto the results to change the form or perform some layered logic.

In the simple example above:

.subscribe(hero => this.hero = hero); basically says on this observable take the hero being emitted and set it to this.hero.

Adding this answer to give more context to Observables based off the documentation and my understanding.

Get Value of a Edit Text field

step 1 : create layout with name activity_main.xml

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rl"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="10dp"
    tools:context=".MainActivity"
    android:background="#c6cabd"
    >
    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="17dp"
        android:textColor="#ff0e13"
        />
    <EditText
        android:id="@+id/et"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tv"
        android:hint="Input your country"
        />
    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Get EditText Text"
        android:layout_below="@id/et"
        />
</RelativeLayout>

Step 2 : Create class Main.class

public class Main extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn = (Button) findViewById(R.id.btn);
        final TextView tv = (TextView) findViewById(R.id.tv);
        final EditText et = (EditText) findViewById(R.id.et);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                String country = et.getText().toString();
                tv.setText("Your inputted country is : " + country);
            }
        });
 }
}

HashMap to return default value for non-found keys?

Not directly, but you can extend the class to modify its get method. Here is a ready to use example: http://www.java2s.com/Code/Java/Collections-Data-Structure/ExtendedVersionofjavautilHashMapthatprovidesanextendedgetmethodaccpetingadefaultvalue.htm

/exclude in xcopy just for a file type

The /EXCLUDE: argument expects a file containing a list of excluded files.

So create a file called excludedfileslist.txt containing:

.cs\

Then a command like this:

xcopy /r /d /i /s /y /exclude:excludedfileslist.txt C:\dev\apan C:\web\apan

Alternatively you could use Robocopy, but would require installing / copying a robocopy.exe to the machines.

Update

An anonymous comment edit which simply stated "This Solution exclude also css file!"

This is true creating a excludedfileslist.txt file contain just:

.cs

(note no backslash on the end)

Will also exclude all of the following:

file1.cs
file2.css
dir1.cs\file3.txt
dir2\anyfile.cs.something.txt

Sometimes people don't read or understand the XCOPY command's help, here is an item I would like to highlight:

Using /exclude

List each string in a separate line in each file. If any of the listed strings match any part of the absolute path of the file to be copied, that file is then excluded from the copying process. For example, if you specify the string "\Obj\", you exclude all files underneath the Obj directory. If you specify the string ".obj", you exclude all files with the .obj extension.

As the example states it excludes "all files with the .obj extension" but it doesn't state that it also excludes files or directories named file1.obj.tmp or dir.obj.output\example2.txt.

There is a way around .css files being excluded also, change the excludedfileslist.txt file to contain just:

.cs\

(note the backslash on the end).

Here is a complete test sequence for your reference:

C:\test1>ver

Microsoft Windows [Version 6.1.7601]

C:\test1>md src
C:\test1>md dst
C:\test1>md src\dir1
C:\test1>md src\dir2.cs
C:\test1>echo "file contents" > src\file1.cs
C:\test1>echo "file contents" > src\file2.css
C:\test1>echo "file contents" > src\dir1\file3.txt
C:\test1>echo "file contents" > src\dir1\file4.cs.txt
C:\test1>echo "file contents" > src\dir2.cs\file5.txt

C:\test1>xcopy /r /i /s /y .\src .\dst
.\src\file1.cs
.\src\file2.css
.\src\dir1\file3.txt
.\src\dir1\file4.cs.txt
.\src\dir2.cs\file5.txt
5 File(s) copied

C:\test1>echo .cs > excludedfileslist.txt
C:\test1>xcopy /r /i /s /y /exclude:excludedfileslist.txt .\src .\dst
.\src\dir1\file3.txt
1 File(s) copied

C:\test1>echo .cs\ > excludedfileslist.txt
C:\test1>xcopy /r /i /s /y /exclude:excludedfileslist.txt .\src .\dst
.\src\file2.css
.\src\dir1\file3.txt
.\src\dir1\file4.cs.txt
3 File(s) copied

This test was completed on a Windows 7 command line and retested on Windows 10 "10.0.14393".

Note that the last example does exclude .\src\dir2.cs\file5.txt which may or may not be unexpected for you.

Flask-SQLalchemy update a row's information

Models.py define the serializers

def default(o):
   if isinstance(o, (date, datetime)):
      return o.isoformat()

class User(db.Model):
   __tablename__='user'
   id = db.Column(db.Integer, primary_key=True, autoincrement=True)
   .......
   ####

    def serializers(self):
       dict_val={"id":self.id,"created_by":self.created_by,"created_at":self.created_at,"updated_by":self.updated_by,"updated_at":self.updated_at}
       return json.loads(json.dumps(dict_val,default=default))

In RestApi, We can update the record dynamically by passing the json data into update query:

class UpdateUserDetails(Resource):
   @auth_token_required
   def post(self):
      json_data = request.get_json()
      user_id = current_user.id
      try:
         instance = User.query.filter(User.id==user_id)
         data=instance.update(dict(json_data))
         db.session.commit()
         updateddata=instance.first()
         msg={"msg":"User details updated successfully","data":updateddata.serializers()}
         code=200
      except Exception as e:
         print(e)
         msg = {"msg": "Failed to update the userdetails! please contact your administartor."}
         code=500
      return msg

Please add a @Pipe/@Directive/@Component annotation. Error

The Above error occurs if any wrong import done. For example sometimes Service files may be added in TestBed.configureTestingModule. And also while importing Material component for example import from

import {MatDialogModule} from '@angular/material/dialog'

not from

import {MatDialogModule} from '@angular/material'

How to extract .war files in java? ZIP vs JAR

WAR file is just a JAR file, to extract it, just issue following jar command –

jar -xvf yourWARfileName.war

If the jar command is not found, which sometimes happens in the Windows command prompt, then specify full path i.e. in my case it is,

 c:\java\jdk-1.7.0\bin\jar -xvf my-file.war

How to deal with SQL column names that look like SQL keywords?

Wrap the column name in brackets like so, from becomes [from].

select [from] from table;

It is also possible to use the following (useful when querying multiple tables):

select table.[from] from table;

SSH configuration: override the default username

man ssh_config says

User
Specifies the user to log in as. This can be useful when a different user name is used on different machines. This saves the trouble of having to remember to give the user name on the command line.

SignalR - Sending a message to a specific user using (IUserIdProvider) NEW 2.0.0

Old thread, but just came across this in a sample:

services.AddSignalR()
            .AddAzureSignalR(options =>
        {
            options.ClaimsProvider = context => new[]
            {
                new Claim(ClaimTypes.NameIdentifier, context.Request.Query["username"])
            };
        });

How to read XML response from a URL in java?

I found that the above answer caused me an exception when I tried to instantiate the parser. I found the following code that resolved this at http://docstore.mik.ua/orelly/xml/sax2/ch03_02.htm.

import org.xml.sax.*;
import javax.xml.parsers.*;

XMLReader        parser;

try {
    SAXParserFactory factory;

    factory = SAXParserFactory.newInstance ();
    factory.setNamespaceAware (true);
    parser = factory.newSAXParser ().getXMLReader ();
    // success!

} catch (FactoryConfigurationError err) {
    System.err.println ("can't create JAXP SAXParserFactory, "
    + err.getMessage ());
} catch (ParserConfigurationException err) {
    System.err.println ("can't create XMLReader with namespaces, "
    + err.getMessage ());
} catch (SAXException err) {
    System.err.println ("Hmm, SAXException, " + err.getMessage ());
}

After Spring Boot 2.0 migration: jdbcUrl is required with driverClassName

As this post gets a bit of popularity I edited it a bit. Spring Boot 2.x.x changed default JDBC connection pool from Tomcat to faster and better HikariCP. Here comes incompatibility, because HikariCP uses different property of jdbc url. There are two ways how to handle it:

OPTION ONE

There is very good explanation and workaround in spring docs:

Also, if you happen to have Hikari on the classpath, this basic setup does not work, because Hikari has no url property (but does have a jdbcUrl property). In that case, you must rewrite your configuration as follows:

app.datasource.jdbc-url=jdbc:mysql://localhost/test
app.datasource.username=dbuser
app.datasource.password=dbpass

OPTION TWO

There is also how-to in the docs how to get it working from "both worlds". It would look like below. ConfigurationProperties bean would do "conversion" for jdbcUrl from app.datasource.url

@Configuration
public class DatabaseConfig {
    @Bean
    @ConfigurationProperties("app.datasource")
    public DataSourceProperties dataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    @ConfigurationProperties("app.datasource")
    public HikariDataSource dataSource(DataSourceProperties properties) {
        return properties.initializeDataSourceBuilder().type(HikariDataSource.class)
                .build();
    }
}

Calculating Waiting Time and Turnaround Time in (non-preemptive) FCFS queue

wt = tt - cpu tm.
Tt = cpu tm + wt.

Where wt is a waiting time and tt is turnaround time. Cpu time is also called burst time.

Android Drawing Separator/Divider Line in Layout?

<TextView
    android:id="@+id/line"
    style="?android:attr/listSeparatorTextViewStyle"
    android:paddingTop="5dip"
    android:gravity="center_horizontal"
    android:layout_below="@+id/connect_help"
    android:layout_width="match_parent"
    android:layout_height="1dp"
    android:background="#000" />

Can I override and overload static methods in Java?

Static methods is a method whose single copy shared by all the objects of the class . Static method belongs to the class rather than objects .since static methods are not depend on the objects , Java Compiler need not wait till the objects creation .so to call static method we uses syntax like ClassName.method() ;

In case of method overloading , methods should be in the same class to overload .even if they are declared as static it is possible to overload them as ,

   Class Sample
    {
         static int calculate(int a,int b,int c)
           {
                int res = a+b+c;
                return res;
           }
           static int calculate(int a,int b)
           {
                int res = a*b;
                return res;
           }
}
class Test
{
   public static void main(String []args)
   {
     int res = Sample.calculate(10,20,30);
   }
}

But in case of method overriding , the method in the super class and the method in the sub class act as different method . the super class will have its own copy and the sub class will have its own copy so it does not come under method overriding .

Escaping Double Quotes in Batch Script

Google eventually came up with the answer. The syntax for string replacement in batch is this:

set v_myvar=replace me
set v_myvar=%v_myvar:ace=icate%

Which produces "replicate me". My script now looks like this:

@echo off
set v_params=%*
set v_params=%v_params:"=\"%
call bash -c "g++-linux-4.1 %v_params%"

Which replaces all instances of " with \", properly escaped for bash.

How to manually deploy artifacts in Nexus Repository Manager OSS 3

For Windows:

mvn deploy:deploy-file -DgroupId=joda-time -DartifactId=joda-time -Dversion=2.7 -Dpackaging=jar -Dfile=joda-time-2.7.jar 
-DgeneratePom=true -DrepositoryId=[Your ID] -Durl=[YourURL]

How to change working directory in Jupyter Notebook?

First you need to create the config file, using cmd : jupyter notebook --generate-config Then, search for C:\Users\your_username\.jupyter folder (Search for that folder), and right click edit the jupyter_notebook_config.py.

Then, Ctrl+F: #c.NotebookApp.notebook_dir ='' . Note that the quotes are single quotes. Select your directory you want to have as home for your jupyter, and copy it with Ctrl+C, for example: C:\Users\username\Python Projects.

Then on that line, paste it like this : c.NotebookApp.notebook_dir = 'C:\\Users\\username\\Python Projects'

Make sure to remove #, as it is as comment.

Make sure to double slash \\ on each name of your path. Ctrl+S to save the config.py file !!!

Go back to your cmd and run jupyter notebook. It should be in your directory of choice. Test it by making a folder and watch your directory from your computer.

How to access random item in list?

Why not[2]:

public static T GetRandom<T>(this List<T> list)
{
     return list[(int)(DateTime.Now.Ticks%list.Count)];
}

Get user input from textarea

Remove the spaces around your =:

<div>    
  <input type="text" [(ngModel)]="str" name="str">
</div>

But you need to have the variable named str on back-end, than its should work fine.

What's the Kotlin equivalent of Java's String[]?

Those types are there so that you can create arrays of the primitives, and not the boxed types. Since String isn't a primitive in Java, you can just use Array<String> in Kotlin as the equivalent of a Java String[].

Postgres could not connect to server

On Yosemite, if the pid file is blocking Postgres from starting and you have a launchctl daemon trying (and failing) to load the database daemons, then you'll need to unload the plist file:

$ launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

Then remove the pid file

$ rm /usr/local/var/postgres/postmaster.pid

Then reload the launchctl daemon

$ launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

WHERE Clause to find all records in a specific month

More one tip very simple. You also could use to_char function, look:

For Month:

to_char(happened_at , 'MM') = 01

For Year:

to_char(happened_at , 'YYYY') = 2009

For Day:

to_char(happened_at , 'DD') = 01

to_char funcion is suported by sql language and not by one specific database.

I hope help anybody more...

Abs!

How do I use NSTimer?

Firstly I'd like to draw your attention to the Cocoa/CF documentation (which is always a great first port of call). The Apple docs have a section at the top of each reference article called "Companion Guides", which lists guides for the topic being documented (if any exist). For example, with NSTimer, the documentation lists two companion guides:

For your situation, the Timer Programming Topics article is likely to be the most useful, whilst threading topics are related but not the most directly related to the class being documented. If you take a look at the Timer Programming Topics article, it's divided into two parts:

Timers
Using Timers

For articles that take this format, there is often an overview of the class and what it's used for, and then some sample code on how to use it, in this case in the "Using Timers" section. There are sections on "Creating and Scheduling a Timer", "Stopping a Timer" and "Memory Management". From the article, creating a scheduled, non-repeating timer can be done something like this:

[NSTimer scheduledTimerWithTimeInterval:2.0
    target:self
    selector:@selector(targetMethod:)
    userInfo:nil
    repeats:NO];

This will create a timer that is fired after 2.0 seconds and calls targetMethod: on self with one argument, which is a pointer to the NSTimer instance.

If you then want to look in more detail at the method you can refer back to the docs for more information, but there is explanation around the code too.

If you want to stop a timer that is one which repeats, (or stop a non-repeating timer before it fires) then you need to keep a pointer to the NSTimer instance that was created; often this will need to be an instance variable so that you can refer to it in another method. You can then call invalidate on the NSTimer instance:

[myTimer invalidate];
myTimer = nil;

It's also good practice to nil out the instance variable (for example if your method that invalidates the timer is called more than once and the instance variable hasn't been set to nil and the NSTimer instance has been deallocated, it will throw an exception).

Note also the point on Memory Management at the bottom of the article:

Because the run loop maintains the timer, from the perspective of memory management there's typically no need to keep a reference to a timer after you’ve scheduled it. Since the timer is passed as an argument when you specify its method as a selector, you can invalidate a repeating timer when appropriate within that method. In many situations, however, you also want the option of invalidating the timer—perhaps even before it starts. In this case, you do need to keep a reference to the timer, so that you can send it an invalidate message whenever appropriate. If you create an unscheduled timer (see “Unscheduled Timers”), then you must maintain a strong reference to the timer (in a reference-counted environment, you retain it) so that it is not deallocated before you use it.

LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup

I got this error while I was trying to turn off precompiled headers in a Console Application Project and removing the header file stdafx.h

To fix this go to your project properties -> Linker -> SubSystem and change the value to Not Set

In your main class, use the standard C++ main function protoype that others have already mentioned :

int main(int argc, char** argv)

Embedding VLC plugin on HTML page

test.html is will be helpful for how to use VLC WebAPI.

test.html is located in the directory where VLC was installed.

e.g. C:\Program Files (x86)\VideoLAN\VLC\sdk\activex\test.html

The following code is a quote from the test.html.

HTML:

<object classid="clsid:9BE31822-FDAD-461B-AD51-BE1D1C159921" width="640" height="360" id="vlc" events="True">
  <param name="MRL" value="" />
  <param name="ShowDisplay" value="True" />
  <param name="AutoLoop" value="False" />
  <param name="AutoPlay" value="False" />
  <param name="Volume" value="50" />
  <param name="toolbar" value="true" />
  <param name="StartTime" value="0" />
  <EMBED pluginspage="http://www.videolan.org"
    type="application/x-vlc-plugin"
    version="VideoLAN.VLCPlugin.2"
    width="640"
    height="360"
    toolbar="true"
    loop="false"
    text="Waiting for video"
    name="vlc">
  </EMBED>
</object>

JavaScript:

You can get vlc object from getVLC().
It works on IE 10 and Chrome.

function getVLC(name)
{
    if (window.document[name])
    {
        return window.document[name];
    }
    if (navigator.appName.indexOf("Microsoft Internet")==-1)
    {
        if (document.embeds && document.embeds[name])
            return document.embeds[name];
    }
    else // if (navigator.appName.indexOf("Microsoft Internet")!=-1)
    {
        return document.getElementById(name);
    }
}

var vlc = getVLC("vlc");

// do something.
// e.g. vlc.playlist.play();

How to open .dll files to see what is written inside?

Open .dll file with visual studio. Or resource editor.

Detect home button press in android

I needed to start/stop background music in my application when first activity opens and closes or when any activity is paused by home button and then resumed from task manager. Pure playback stopping/resuming in Activity.onPause() and Activity.onResume() interrupted the music for a while, so I had to write the following code:

@Override
public void onResume() {
  super.onResume();

  // start playback here (if not playing already)
}

@Override
public void onPause() {
  super.onPause();

  ActivityManager manager = (ActivityManager) this.getSystemService(Activity.ACTIVITY_SERVICE);
  List<ActivityManager.RunningTaskInfo> tasks = manager.getRunningTasks(Integer.MAX_VALUE);
  boolean is_finishing = this.isFinishing();
  boolean is_last = false;
  boolean is_topmost = false;
  for (ActivityManager.RunningTaskInfo task : tasks) {
    if (task.topActivity.getPackageName().startsWith("cz.matelier.skolasmyku")) {
      is_last = task.numRunning == 1;
      is_topmost = task.topActivity.equals(this.getComponentName());
      break;
    }
  }

  if ((is_finishing && is_last) || (!is_finishing && is_topmost && !mIsStarting)) {
    mIsStarting = false;
    // stop playback here
  }
}

which interrupts the playback only when application (all its activities) is closed or when home button is pressed. Unfortunatelly I didn't manage to change order of calls of onPause() method of the starting activity and onResume() of the started actvity when Activity.startActivity() is called (or detect in onPause() that activity is launching another activity other way) so this case have to be handled specially:

private boolean mIsStarting;

@Override
public void startActivity(Intent intent) {
  mIsStarting = true;
  super.startActivity(intent);
}

Another drawback is that this requires GET_TASKS permission added to AndroidManifest.xml:

<uses-permission
  android:name="android.permission.GET_TASKS"/>

Modifying this code that it only reacts on home button press is straighforward.

Filename timestamp in Windows CMD batch script getting truncated

It wants the full time in DD-MM-YYYY_HH-MM-SS.TT where TT is the ticks. The exception says it all.

Java JTable setting Column Width

This code is worked for me without setAutoResizeModes.

        TableColumnModel columnModel = jTable1.getColumnModel();
        columnModel.getColumn(1).setPreferredWidth(170);
        columnModel.getColumn(1).setMaxWidth(170);
        columnModel.getColumn(2).setPreferredWidth(150);
        columnModel.getColumn(2).setMaxWidth(150);
        columnModel.getColumn(3).setPreferredWidth(40);
        columnModel.getColumn(3).setMaxWidth(40);

Formatting Phone Numbers in PHP

Check Phone number

$phone = '+385 99 1234 1234'

$str = preg_match('/^\+?\d{1,3}[\s-]?\d{1,3}[\s-]?\d{1,4}[\s-]?\d{1,4}$/', $phone);

if($str){
return true;
}else{
return false;
}

Failed to instantiate module error in Angular js

For me the error occurred due to my browser using a cached version of the js file containing the module. Clearing the cache and reloading the page solved the problem.

Procedure or function !!! has too many arguments specified

For those who might have the same problem as me, I got this error when the DB I was using was actually master, and not the DB I should have been using.

Just put use [DBName] on the top of your script, or manually change the DB in use in the SQL Server Management Studio GUI.

Assign width to half available screen width declaratively

If your widget is a Button:

<LinearLayout android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:weightSum="2"
    android:orientation="horizontal">
    <Button android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="somebutton"/>

    <TextView android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"/>
</LinearLayout>

I'm assuming you want your widget to take up one half, and another widget to take up the other half. The trick is using a LinearLayout, setting layout_width="fill_parent" on both widgets, and setting layout_weight to the same value on both widgets as well. If there are two widgets, both with the same weight, the LinearLayout will split the width between the two widgets.

What does the variable $this mean in PHP?

The best way to learn about the `$this` variable in PHP is to try it against the interpreter in various contexts:

print isset($this);              //true,   $this exists
print gettype($this);            //Object, $this is an object 
print is_array($this);           //false,  $this isn't an array
print get_object_vars($this);    //true,   $this's variables are an array
print is_object($this);          //true,   $this is still an object
print get_class($this);          //YourProject\YourFile\YourClass
print get_parent_class($this);   //YourBundle\YourStuff\YourParentClass
print gettype($this->container); //object
print_r($this);                  //delicious data dump of $this
print $this->yourvariable        //access $this variable with ->

So the $this pseudo-variable has the Current Object's method's and properties. Such a thing is useful because it lets you access all member variables and member methods inside the class. For example:

Class Dog{
    public $my_member_variable;                             //member variable

    function normal_method_inside_Dog() {                   //member method

        //Assign data to member variable from inside the member method
        $this->my_member_variable = "whatever";

        //Get data from member variable from inside the member method.
        print $this->my_member_variable;
    }
}

$this is reference to a PHP Object that was created by the interpreter for you, that contains an array of variables.

If you call $this inside a normal method in a normal class, $this returns the Object (the class) to which that method belongs.

It's possible for $this to be undefined if the context has no parent Object.

php.net has a big page talking about PHP object oriented programming and how $this behaves depending on context. https://www.php.net/manual/en/language.oop5.basic.php

How to calculate the time interval between two time strings

Try this -- it's efficient for timing short-term events. If something takes more than an hour, then the final display probably will want some friendly formatting.

import time
start = time.time()

time.sleep(10)  # or do something more productive

done = time.time()
elapsed = done - start
print(elapsed)

The time difference is returned as the number of elapsed seconds.

Pass Javascript Variable to PHP POST

Your idea of an hidden form element is solid. Something like this

<form action="script.php" method="post">
<input type="hidden" name="total" id="total">
</form>

<script type="text/javascript">
var element = document.getElementById("total");
element.value = getTotalFromSomewhere;
element.form.submit();
</script>

Of course, this will change the location to script.php. If you want to do this invisibly to the user, you'll want to use AJAX. Here's a jQuery example (for brevity). No form or hidden inputs required

$.post("script.php", { total: getTotalFromSomewhere });

What does 'const static' mean in C and C++?

A lot of people gave the basic answer but nobody pointed out that in C++ const defaults to static at namespace level (and some gave wrong information). See the C++98 standard section 3.5.3.

First some background:

Translation unit: A source file after the pre-processor (recursively) included all its include files.

Static linkage: A symbol is only available within its translation unit.

External linkage: A symbol is available from other translation units.

At `namespace` level

This includes the global namespace aka global variables.

static const int sci = 0; // sci is explicitly static
const int ci = 1;         // ci is implicitly static
extern const int eci = 2; // eci is explicitly extern
extern int ei = 3;        // ei is explicitly extern
int i = 4;                // i is implicitly extern
static int si = 5;        // si is explicitly static

At function level

static means the value is maintained between function calls.
The semantics of function static variables is similar to global variables in that they reside in the program's data-segment (and not the stack or the heap), see this question for more details about static variables' lifetime.

At `class` level

static means the value is shared between all instances of the class and const means it doesn't change.

ASP.NET Custom Validator Client side & Server Side validation not firing

Server-side validation won't fire if client-side validation is invalid, the postback is not send.

Don't you have some other validation that doesn't pass?

The client-side validation is not executed because you specified ClientValidationFunction="TextBoxDTownCityClient" and this will look for a function named TextBoxDTownCityClient as validation function, but the function name should be TextBoxDAddress1Client

(as you wrote)

How can I query for null values in entity framework?

Personnally, I prefer:

var result = from entry in table    
             where (entry.something??0)==(value??0)                    
              select entry;

over

var result = from entry in table
             where (value == null ? entry.something == null : entry.something == value)
             select entry;

because it prevents repetition -- though that's not mathematically exact, but it fits well most cases.

Python: Get relative path from comparing two absolute paths

os.path.commonprefix() and os.path.relpath() are your friends:

>>> print os.path.commonprefix(['/usr/var/log', '/usr/var/security'])
'/usr/var'
>>> print os.path.commonprefix(['/tmp', '/usr/var'])  # No common prefix: the root is the common prefix
'/'

You can thus test whether the common prefix is one of the paths, i.e. if one of the paths is a common ancestor:

paths = […, …, …]
common_prefix = os.path.commonprefix(list_of_paths)
if common_prefix in paths:
    …

You can then find the relative paths:

relative_paths = [os.path.relpath(path, common_prefix) for path in paths]

You can even handle more than two paths, with this method, and test whether all the paths are all below one of them.

PS: depending on how your paths look like, you might want to perform some normalization first (this is useful in situations where one does not know whether they always end with '/' or not, or if some of the paths are relative). Relevant functions include os.path.abspath() and os.path.normpath().

PPS: as Peter Briggs mentioned in the comments, the simple approach described above can fail:

>>> os.path.commonprefix(['/usr/var', '/usr/var2/log'])
'/usr/var'

even though /usr/var is not a common prefix of the paths. Forcing all paths to end with '/' before calling commonprefix() solves this (specific) problem.

PPPS: as bluenote10 mentioned, adding a slash does not solve the general problem. Here is his followup question: How to circumvent the fallacy of Python's os.path.commonprefix?

PPPPS: starting with Python 3.4, we have pathlib, a module that provides a saner path manipulation environment. I guess that the common prefix of a set of paths can be obtained by getting all the prefixes of each path (with PurePath.parents()), taking the intersection of all these parent sets, and selecting the longest common prefix.

PPPPPS: Python 3.5 introduced a proper solution to this question: os.path.commonpath(), which returns a valid path.

Dividing two integers to produce a float result

Cast the operands to floats:

float ans = (float)a / (float)b;

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

$('#formID')[0].reset(); // Reset all form fields

IntelliJ IDEA generating serialVersionUID

After spending some time on Serialization, I find that, we should not generate serialVersionUID with some random value, we should give it a meaningful value.

Here is a details comment on this. I am coping the comment here.

Actually, you should not be "generating" serial version UIDs. It is a dumb "feature" that stems from the general misunderstanding of how that ID is used by Java. You should be giving these IDs meaningful, readable values, e.g. starting with 1L, and incrementing them each time you think the new version of the class should render all previous versions (that might be previously serialized) obsolete. All utilities that generate such IDs basically do what the JVM does when the ID is not defined: they generate the value based on the content of the class file, hence coming up with unreadable meaningless long integers. If you want each and every version of your class to be distinct (in the eyes of the JVM) then you should not even specify the serialVersionUID value isnce the JVM will produce one on the fly, and the value of each version of your class will be unique. The purpose of defining that value explicitly is to tell the serialization mechanism to treat different versions of the class that have the same SVUID as if they are the same, e.g. not to reject the older serialized versions. So, if you define the ID and never change it (and I assume that's what you do since you rely on the auto-generation, and you probably never re-generate your IDs) you are ensuring that all - even absolutely different - versions of your class will be considered the same by the serialization mechanism. Is that what you want? If not, and if you indeed want to have control over how your objects are recognized, you should be using simple values that you yourself can understand and easily update when you decide that the class has changed significantly. Having a 23-digit value does not help at all.

Hope this helps. Good luck.

Effects of the extern keyword on C functions

The extern keyword takes on different forms depending on the environment. If a declaration is available, the extern keyword takes the linkage as that specified earlier in the translation unit. In the absence of any such declaration, extern specifies external linkage.

static int g();
extern int g(); /* g has internal linkage */

extern int j(); /* j has tentative external linkage */

extern int h();
static int h(); /* error */

Here are the relevant paragraphs from the C99 draft (n1256):

6.2.2 Linkages of identifiers

[...]

4 For an identifier declared with the storage-class specifier extern in a scope in which a prior declaration of that identifier is visible,23) if the prior declaration specifies internal or external linkage, the linkage of the identifier at the later declaration is the same as the linkage specified at the prior declaration. If no prior declaration is visible, or if the prior declaration specifies no linkage, then the identifier has external linkage.

5 If the declaration of an identifier for a function has no storage-class specifier, its linkage is determined exactly as if it were declared with the storage-class specifier extern. If the declaration of an identifier for an object has file scope and no storage-class specifier, its linkage is external.

NameError: name 'datetime' is not defined

It can also be used as below:

from datetime import datetime
start_date = datetime(2016,3,1)
end_date = datetime(2016,3,10)

What exactly does big ? notation represent?

First of All Theory

Big O = Upper Limit O(n)
Theta = Order Function - theta(n)
Omega = Q-Notation(Lower Limit) Q(n)

Why People Are so Confused?

In many Blogs & Books How this Statement is emphasised is Like

"This is Big O(n^3)" etc.

and people often Confuse like weather

O(n) == theta(n) == Q(n)

But What Worth keeping in mind is They Are Just Mathematical Function With Names O, Theta & Omega

so they have same General Formula of Polynomial,

Let,

f(n) = 2n4 + 100n2 + 10n + 50 then,

g(n) = n4, So g(n) is Function which Take function as Input and returns Variable with Biggerst Power,

Same f(n) & g(n) for Below all explainations

Big O - Function (Provides Upper Bound)

Big O(n4) = 3n4, Because 3n4 > 2n4

3n4 is value of Big O(n4) Just like f(x) = 3x

n4 is playing a role of x here so,

Replacing n4 with x'so, Big O(x') = 2x', Now we both are happy General Concept is

So 0 = f(n) = O(x')

O(x') = cg(n) = 3n4

Putting Value,

0 = 2n4 + 100n2 + 10n + 50 = 3n4

3n4 is our Upper Bound

Theta(n) Provides Lower Bound

Theta(n4) = cg(n) = 2n4 Because 2n4 = Our Example f(n)

2n4 is Value of Theta(n4)

so, 0 = cg(n) = f(n)

0 = 2n4 = 2n4 + 100n2 + 10n + 50

2n4 is our Lower Bound

Omega n - Order Function

This is Calculated to find out that weather lower Bound is similar to Upper bound,

Case 1). Upper Bound is Similar to Lower Bound

if Upper Bound is Similar to Lower Bound, The Average Case is Similar

Example, 2n4 = f(x) = 2n4,
Then Omega(n) = 2n4

Case 2). if Upper Bound is not Similar to Lower Bound

in this case, Omega(n) is Not fixed but Omega(n) is the set of functions with the same order of growth as g(n).

Example 2n4 = f(x) = 3n4, This is Our Default Case,
Then, Omega(n) = c'n4, is a set of functions with 2 = c' = 3

Hope This Explained!!

How do you overcome the HTML form nesting limitation?

I would implement this exactly as you described: submit everything to the server and do a simple if/else to check what button was clicked.

And then I would implement a Javascript call tying into the form's onsubmit event which would check before the form was submitted, and only submit the relevant data to the server (possibly through a second form on the page with the ID needed to process the thing as a hidden input, or refresh the page location with the data you need passed as a GET request, or do an Ajax post to the server, or...).

This way the people without Javascript are able to use the form just fine, but the server load is offset because the people who do have Javascript are only submitting the single piece of data needed. Getting yourself focused on only supporting one or the other really limits your options unnecessarily.

Alternatively, if you're working behind a corporate firewall or something and everybody has Javascript disabled, you might want to do two forms and work some CSS magic to make it look like the delete button is part of the first form.

Best Practice to Use HttpClient in Multithreaded Environment

Definitely Method A because its pooled and thread safe.

If you are using httpclient 4.x, the connection manager is called ThreadSafeClientConnManager. See this link for further details (scroll down to "Pooling connection manager"). For example:

    HttpParams params = new BasicHttpParams();
    SchemeRegistry registry = new SchemeRegistry();
    registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
    ClientConnectionManager cm = new ThreadSafeClientConnManager(params, registry);
    HttpClient client = new DefaultHttpClient(cm, params);

Java ResultSet how to check if there are any results

That's correct, initially the ResultSet's cursor is pointing to before the first row, if the first call to next() returns false then there was no data in the ResultSet.

If you use this method, you may have to call beforeFirst() immediately after to reset it, since it has positioned itself past the first row now.

It should be noted however, that Seifer's answer below is a more elegant solution to this question.

Counting Chars in EditText Changed Listener

This is a slightly more general answer with more explanation for future viewers.

Add a text changed listener

If you want to find the text length or do something else after the text has been changed, you can add a text changed listener to your edit text.

EditText editText = (EditText) findViewById(R.id.testEditText);
editText.addTextChangedListener(new TextWatcher() {

    @Override
    public void beforeTextChanged(CharSequence charSequence, int start, int count, int after) {

    }

    @Override
    public void onTextChanged(CharSequence charSequence, int start, int before, int count)  {

    }

    @Override
    public void afterTextChanged(Editable editable) {

    }
});

The listener needs a TextWatcher, which requires three methods to be overridden: beforeTextChanged, onTextChanged, and afterTextChanged.

Counting the characters

You can get the character count in onTextChanged or beforeTextChanged with

charSequence.length()

or in afterTextChanged with

editable.length()

Meaning of the methods

The parameters are a little confusing so here is a little extra explanation.

beforeTextChanged

beforeTextChanged(CharSequence charSequence, int start, int count, int after)

charSequence: This is the text content before the pending change is made. You should not try to change it.
start: This is the index of where the new text will be inserted. If a range is selected, then it is the beginning index of the range.
count: This is the length of selected text that is going to be replaced. If nothing is selected then count will be 0.
after: this is the length of the text to be inserted.

onTextChanged

onTextChanged(CharSequence charSequence, int start, int before, int count)

charSequence: This is the text content after the change was made. You should not try to modify this value here. Modify the editable in afterTextChanged if you need to.
start: This is the index of the start of where the new text was inserted.
before: This is the old value. It is the length of previously selected text that was replaced. This is the same value as count in beforeTextChanged.
count: This is the length of text that was inserted. This is the same value as after in beforeTextChanged.

afterTextChanged

afterTextChanged(Editable editable)

Like onTextChanged, this is called after the change has already been made. However, now the text may be modified.

editable: This is the editable text of the EditText. If you change it, though, you have to be careful not to get into an infinite loop. See the documentation for more details.

Supplemental image from this answer

Finding the mode of a list

Why not just

def print_mode (thelist):
  counts = {}
  for item in thelist:
    counts [item] = counts.get (item, 0) + 1
  maxcount = 0
  maxitem = None
  for k, v in counts.items ():
    if v > maxcount:
      maxitem = k
      maxcount = v
  if maxcount == 1:
    print "All values only appear once"
  elif counts.values().count (maxcount) > 1:
    print "List has multiple modes"
  else:
    print "Mode of list:", maxitem

This doesn't have a few error checks that it should have, but it will find the mode without importing any functions and will print a message if all values appear only once. It will also detect multiple items sharing the same maximum count, although it wasn't clear if you wanted that.

Place API key in Headers or URL

passing api key in parameters makes it difficult for clients to keep their APIkeys secret, they tend to leak keys on a regular basis. A better approach is to pass it in header of request url.you can set user-key header in your code . For testing your request Url you can use Postman app in google chrome by setting user-key header to your api-key.

Git Bash won't run my python files?

That command did not work for me, I used:

$ export PATH="$PATH:/c/Python27"

Then to make sure that git remembers the python path every time you open git type the following.

echo 'export PATH="$PATH:/c/Python27"' > .profile

port 8080 is already in use and no process using 8080 has been listed

If no other process is using the port 8080, Eventhough eclipse shows the port 8080 is used while starting the server in eclipse, first you have to stop the server by hitting the stop button in "Configure Tomcat"(which you can find in your start menu under tomcat folder), then try to start the server in eclipse then it will be started.

If any other process is using the port 8080 and as well as you no need to disturb it. then you can change the port.

How to fix Error: "Could not find schema information for the attribute/element" by creating schema

An XSD is included with EntLib 5, and is installed in the Visual Studio schema directory. In my case, it could be found at:

C:\Program Files (x86)\Microsoft Visual Studio 10.0\Xml\Schemas\EnterpriseLibrary.Configuration.xsd

CONTEXT

Visual Studio 2010
Enterprise Library 5

STEPS TO REMOVE THE WARNINGS

open app.config in your Visual Studio project
right click in the XML Document editor, select "Properties"
add the fully qualified path to the "EnterpriseLibrary.Configuration.xsd"

ASIDE

It is worth repeating that these "Error List" "Messages" ("Could not find schema information for the element") are only visible when you open the app.config file. If you "Close All Documents" and compile... no messages will be reported.

App.Config file in console application C#

You can add a reference to System.Configuration in your project and then:

using System.Configuration;

then

string sValue = ConfigurationManager.AppSettings["BatchFile"];

with an app.config file like this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
   <appSettings>
       <add key="BatchFile" value="blah.bat" />
   </appSettings>
</configuration>

Non-static method requires a target

All the answers are pointing to a Lambda expression with an NRE (Null Reference Exception). I have found that it also occurs when using Linq to Entities. I thought it would be helpful to point out that this exception is not limited to just an NRE inside a Lambda expression.

Windows 7 environment variable not working in path

Also worth making sure you're using the command prompt as an administrator - the system lock on my work machine meant that the standard cmd just reported mvn could not be found when typing mvn --version

To use click 'start > all programs > accessories', right-click on 'command prompt' and select 'run as administrator'.

how to change namespace of entire project?

When renaming a project, it's a simple process

Rename your project
Edit project properties to have new Default Namespace value
Find/Replace all "namespace OLD" and "using OLD" statements in your solution
Manually edit .sln file in text editor and replace your old project name in the directory structure with your new project name.
Reload solution when VS prompts

Determine the process pid listening on a certain port

The -p flag of netstat gives you PID of the process:

netstat -l -p

Edit: The command that is needed to get PIDs of socket users in FreeBSD is sockstat. As we worked out during the discussion with @Cyclone, the line that does the job is:

sockstat -4 -l | grep :80 | awk '{print $3}' | head -1

When are static variables initialized?

Starting with the code from the other question:

class MyClass {
  private static MyClass myClass = new MyClass();
  private static final Object obj = new Object();
  public MyClass() {
    System.out.println(obj); // will print null once
  }
}

A reference to this class will start initialization. First, the class will be marked as initialized. Then the first static field will be initialized with a new instance of MyClass(). Note that myClass is immediately given a reference to a blank MyClass instance. The space is there, but all values are null. The constructor is now executed and prints obj, which is null.

Now back to initializing the class: obj is made a reference to a new real object, and we're done.

If this was set off by a statement like: MyClass mc = new MyClass(); space for a new MyClass instance is again allocated (and the reference placed in mc). The constructor is again executed and again prints obj, which now is not null.

The real trick here is that when you use new, as in WhatEverItIs weii = new WhatEverItIs( p1, p2 ); weii is immediately given a reference to a bit of nulled memory. The JVM will then go on to initialize values and run the constructor. But if you somehow reference weii before it does so--by referencing it from another thread or or by referencing from the class initialization, for instance--you are looking at a class instance filled with null values.

Javascript one line If...else...else if statement

  a === "a" ? do something
: a === "b" ? do something
: do something

Function pointer as parameter

Replace void *disconnectFunc; with void (*disconnectFunc)(); to declare function pointer type variable. Or even better use a typedef:

typedef void (*func_t)(); // pointer to function with no args and void return
...
func_t fptr; // variable of pointer to function
...
void D::setDisconnectFunc( func_t func )
{
    fptr = func;
}

void D::disconnected()
{
    fptr();
    connected = false;
}

cat, grep and cut - translated to python

For Translating the command to python refer below:-

1)Alternative of cat command is open refer this. Below is the sample

>>> f = open('workfile', 'r')
>>> print f

2)Alternative of grep command refer this

3)Alternative of Cut command refer this

java.net.UnknownHostException: Invalid hostname for server: local

Try the following :

String url = "http://www.google.com/search?q=java";
URL urlObj = (URL)new URL(url.trim());
HttpURLConnection httpConn = 
(HttpURLConnection)urlObj.openConnection();
httpConn.setRequestMethod("GET");
Integer rescode = httpConn.getResponseCode();
System.out.println(rescode);

Trim() the URL

How to use GNU Make on Windows?

user1594322 gave a correct answer but when I tried it I ran into admin/permission problems. I was able to copy 'mingw32-make.exe' and paste it, over-ruling/by-passing admin issues and then editing the copy to 'make.exe'. On VirtualBox in a Win7 guest.

C# static class constructor

You can use static constructor to initialization static variable. Static constructor will be entry point for your class

public class MyClass
{

    static MyClass()
    {

        //write your initialization code here
    }

}

How to make a div with a circular shape?

HTML div elements, unlike SVG circle primitives, are always rectangular.

You could use round corners (i.e. CSS border-radius) to make it look round. On square elements, a value of 50% naturally forms a circle. Use this, or even a SVG inside your HTML:

_x000D_

document.body.innerHTML+='<i></i>'.repeat(4);

_x000D_

i{border-radius:50%;display:inline-block;background:#F48024;}
svg {fill:#F48024;width:60px;height:60px;}
i:nth-of-type(1n){width:30px;height:30px;}
i:nth-of-type(2n){width:60px;height:60px;}

_x000D_

<svg viewBox="0 0 120 120" xmlns="http://www.w3.org/2000/svg">
  <circle cx="60" cy="60" r="60"/>
</svg>

_x000D_

Error Code: 2013. Lost connection to MySQL server during query

If all the other solutions here fail - check your syslog (/var/log/syslog or similar) to see if your server is running out of memory during the query.

Had this issue when innodb_buffer_pool_size was set too close to physical memory without a swapfile configured. MySQL recommends for a database specific server setting innodb_buffer_pool_size at a max of around 80% of physical memory, I had it set to around 90%, the kernel was killing the mysql process. Moved innodb_buffer_pool_size back down to around 80% and that fixed the issue.

EF Code First "Invalid column name 'Discriminator'" but no inheritance

Here is the Fluent API syntax.

http://blogs.msdn.com/b/adonet/archive/2010/12/06/ef-feature-ctp5-fluent-api-samples.aspx

class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string FullName { 
        get {
            return this.FirstName + " " + this.LastName;
        }
    }
}

class PersonViewModel : Person
{
    public bool UpdateProfile { get; set; }
}


protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    // ignore a type that is not mapped to a database table
    modelBuilder.Ignore<PersonViewModel>();

    // ignore a property that is not mapped to a database column
    modelBuilder.Entity<Person>()
        .Ignore(p => p.FullName);

}

How to find all trigger associated with a table with SQL Server?

Try to Use:

select * from sys.objects where type='tr' and name like '%_Insert%'

How to delete a folder and all contents using a bat file in windows?

del /s /q c:\where ever the file is\*
rmdir /s /q c:\where ever the file is\
mkdir c:\where ever the file is\

Reloading submodules in IPython

I hate to add yet another answer to a long thread, but I found a solution that enables recursive reloading of submodules on %run() that others might find useful (I have anyway)

del the submodule you wish to reload on run from sys.modules in iPython:

In[1]: from sys import modules
In[2]: del modules["mymodule.mysubmodule"] # tab completion can be used like mymodule.<tab>!

Now your script will recursively reload this submodule:

In[3]: %run myscript.py

JQuery show/hide when hover

This code also works.

_x000D_

$(".circle").hover(function() {$(this).hide(200).show(200);});

_x000D_

.circle{_x000D_
    width:100px;_x000D_
    height:100px;_x000D_
    border-radius:50px;_x000D_
    font-size:20px;_x000D_
    color:black;_x000D_
    line-height:100px;_x000D_
    text-align:center;_x000D_
    background:yellow_x000D_
}

_x000D_

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.0/jquery.min.js"></script>_x000D_
<div class="circle">hover me</div>

_x000D_

What are the specific differences between .msi and setup.exe file?

.msi files are windows installer files without the windows installer runtime, setup.exe can be any executable programm (probably one that installs stuff on your computer)

How to Select Top 100 rows in Oracle?

As Moneer Kamal said, you can do that simply:

SELECT id, client_id FROM order 
WHERE rownum <= 100
ORDER BY create_time DESC;

Notice that the ordering is done after getting the 100 row. This might be useful for who does not want ordering.

How can I split a text into sentences?

You can try using Spacy instead of regex. I use it and it does the job.

import spacy
nlp = spacy.load('en')

text = '''Your text here'''
tokens = nlp(text)

for sent in tokens.sents:
    print(sent.string.strip())

laravel 5.5 The page has expired due to inactivity. Please refresh and try again

Still anyone have this problem, use following code inside your form as below.

 echo '<input type = "hidden" name = "_token" value = "'. csrf_token().'" >';

scrollTop jquery, scrolling to div with id?

try this:

$('html, body').animate({scrollTop:$('#xxx').position().top}, 'slow');
$('#xxx').focus();

Simplest way to append data to a SQL Column

Angular.js How to change an elements css class on click and to remove all others

To me it seems like the best solution is to use a directive; there's no need for the controller to know that the view is being updated.

Javascript:

var app = angular.module('app', ['directives']);

angular.module('directives', []).directive('toggleClass', function () {
    var directiveDefinitionObject = {
        restrict: 'A',
        template: '<span ng-click="localFunction()" ng-class="selected"  ng-transclude></span>',
        replace: true,
        scope: {
            model: '='
        },
        transclude: true,
        link: function (scope, element, attrs) {
            scope.localFunction = function () {
                scope.model.value = scope.$id;
            };
            scope.$watch('model.value', function () {
                // Is this set to my scope?
                if (scope.model.value === scope.$id) {
                    scope.selected = "active";
                } else {
                    // nope
                    scope.selected = '';
                }
            });
        }
    };
    return directiveDefinitionObject;
});

HTML:

<div ng-app="app" ng-init="model = { value: 'dsf'}"> <span>Click a span... then click another</span>

<br/>
<br/>
<span toggle-class model="model">span1</span>

<br/><span toggle-class model="model">span2</span>

<br/><span toggle-class model="model">span3</span>

CSS:

.active {
     color:red;
 }

I have a fiddle that demonstrates. The idea is when a directive is clicked, a function is called on the directive that sets a variable to the current scope id. Then each directive also watches the same value. If the scope ID's match, then the current element is set to be active using ng-class.

The reason to use directives, is that you no longer are dependent on a controller. In fact I don't have a controller at all (I do define a variable in the view named "model"). You can then reuse this directive anywhere in your project, not just on one controller.

How to send parameters with jquery $.get()

If you say that it works with accessing directly manageproducts.do?option=1 in the browser then it should work with:

$.get('manageproducts.do', { option: '1' }, function(data) {
    ...
});

as it would send the same GET request.

Oracle insert if not exists statement

insert into OPT (email, campaign_id) 
select '[email protected]',100
from dual
where not exists(select * 
                 from OPT 
                 where (email ='[email protected]' and campaign_id =100));

How do I fix this "TypeError: 'str' object is not callable" error?

this part :

"Your new price is: $"(float(price)

asks python to call this string:

"Your new price is: $"

just like you would a function: function( some_args) which will ALWAYS trigger the error:

TypeError: 'str' object is not callable

How to get the host name of the current machine as defined in the Ansible hosts file?

This is an alternative:

- name: Install this only for local dev machine
  pip: name=pyramid
  delegate_to: localhost

Meaning of "487 Request Terminated"

It's the response code a SIP User Agent Server (UAS) will send to the client after the client sends a CANCEL request for the original unanswered INVITE request (yet to receive a final response).

Here is a nice CANCEL SIP Call Flow illustration.

Getting RAW Soap Data from a Web Reference Client running in ASP.net

Not sure why all the fuss with web.config or a serializer class. The below code worked for me:

XmlSerializer xmlSerializer = new XmlSerializer(myEnvelope.GetType());

using (StringWriter textWriter = new StringWriter())
{
    xmlSerializer.Serialize(textWriter, myEnvelope);
    return textWriter.ToString();
}

Understanding Python super() with init() methods

It's been noted that in Python 3.0+ you can use

super().__init__()

to make your call, which is concise and does not require you to reference the parent OR class names explicitly, which can be handy. I just want to add that for Python 2.7 or under, some people implement a name-insensitive behaviour by writing self.__class__ instead of the class name, i.e.

super(self.__class__, self).__init__()  # DON'T DO THIS!

HOWEVER, this breaks calls to super for any classes that inherit from your class, where self.__class__ could return a child class. For example:

class Polygon(object):
    def __init__(self, id):
        self.id = id

class Rectangle(Polygon):
    def __init__(self, id, width, height):
        super(self.__class__, self).__init__(id)
        self.shape = (width, height)

class Square(Rectangle):
    pass

Here I have a class Square, which is a sub-class of Rectangle. Say I don't want to write a separate constructor for Square because the constructor for Rectangle is good enough, but for whatever reason I want to implement a Square so I can reimplement some other method.

When I create a Square using mSquare = Square('a', 10,10), Python calls the constructor for Rectangle because I haven't given Square its own constructor. However, in the constructor for Rectangle, the call super(self.__class__,self) is going to return the superclass of mSquare, so it calls the constructor for Rectangle again. This is how the infinite loop happens, as was mentioned by @S_C. In this case, when I run super(...).__init__() I am calling the constructor for Rectangle but since I give it no arguments, I will get an error.

Package signatures do not match the previously installed version

If you are trying to install it in an Emulator but have another phone connected to the computer via USB, detach the USB cable or disable USB debugging in the physical device. (Wasted 30min on it myself.)

How to compare LocalDate instances Java 8

Using equals() LocalDate does override equals:

int compareTo0(LocalDate otherDate) {
    int cmp = (year - otherDate.year);
    if (cmp == 0) {
        cmp = (month - otherDate.month);
        if (cmp == 0) {
            cmp = (day - otherDate.day);
        }
    }
    return cmp;
}

If you are not happy with the result of equals(), you are good using the predefined methods of LocalDate.

Notice that all of those method are using the compareTo0() method and just check the cmp value. if you are still getting weird result (which you shouldn't), please attach an example of input and output

How to render a DateTime in a specific format in ASP.NET MVC 3?

if I just want to display the date in short format I just use @Model.date.ToShortDateString() and it prints the date in

Convert string to Time

string Time = "16:23:01";
DateTime date = DateTime.Parse(Time, System.Globalization.CultureInfo.CurrentCulture);

string t = date.ToString("HH:mm:ss tt");

How do I install opencv using pip?

As a reference it might help someone... On Debian system I hard to do the following:

apt-get install -y libsm6 libxext6 libxrender-dev
pip3 install opencv-python
python3 -c "import cv2"

Adding a column after another column within SQL

In a Firebird database the AFTER myOtherColumn does not work but you can try re-positioning the column using:

ALTER TABLE name ALTER column POSITION new_position

I guess it may work in other cases as well.

Purpose of Activator.CreateInstance with example?

Say you have a class called MyFancyObject like this one below:

class MyFancyObject
{
 public int A { get;set;}
}

It lets you turn:

String ClassName = "MyFancyObject";

Into

MyFancyObject obj;

Using

obj = (MyFancyObject)Activator.CreateInstance("MyAssembly", ClassName))

and can then do stuff like:

obj.A = 100;

That's its purpose. It also has many other overloads such as providing a Type instead of the class name in a string. Why you would have a problem like that is a different story. Here's some people who needed it:

Extracting time from POSIXct

There have been previous answers that showed the trick. In essence:

you must retain POSIXct types to take advantage of all the existing plotting functions
if you want to 'overlay' several days worth on a single plot, highlighting the intra-daily variation, the best trick is too ...
impose the same day (and month and even year if need be, which is not the case here)

which you can do by overriding the day-of-month and month components when in POSIXlt representation, or just by offsetting the 'delta' relative to 0:00:00 between the different days.

So with times and val as helpfully provided by you:

## impose month and day based on first obs
ntimes <- as.POSIXlt(times)    # convert to 'POSIX list type'
ntimes$mday <- ntimes[1]$mday  # and $mon if it differs too
ntimes <- as.POSIXct(ntimes)   # convert back

par(mfrow=c(2,1))
plot(times,val)   # old times
plot(ntimes,val)  # new times

yields this contrasting the original and modified time scales:

enter image description here

System has not been booted with systemd as init system (PID 1). Can't operate

If you are using Docker, you may try an image that has Ubuntu with System D already active with this command:

docker run -d --name redis --privileged -v /sys/fs/cgroup:/sys/fs/cgroup:ro jrei/systemd-ubuntu:18.04

Then you just need to run:

docker exec -it redis /bin/bash

and there you can just install Redis, start it, restart it or whatever you need.

Add timer to a Windows Forms application

Download http://download.cnet.com/Free-Desktop-Timer/3000-2350_4-75415517.html

Then add a button or something on the form and inside its event, just open this app ie:

{

Process.Start(@"C:\Program Files (x86)\Free Desktop Timer\DesktopTimer");

}

Java dynamic array sizes?

In Java Array Sizes are always of Fixed Length But there is way in which you can Dynamically increase the Size of the Array at Runtime Itself

This is the most "used" as well as preferred way to do it-

    int temp[]=new int[stck.length+1];
    for(int i=0;i<stck.length;i++)temp[i]=stck[i];
    stck=temp;

In the above code we are initializing a new temp[] array, and further using a for loop to initialize the contents of the temp with the contents of the original array ie. stck[]. And then again copying it back to the original one, giving us a new array of new SIZE.

No doubt it generates a CPU Overhead due to reinitializing an array using for loop repeatedly. But you can still use and implement it in your code. For the best practice use "Linked List" instead of Array, if you want the data to be stored dynamically in the memory, of variable length.

Here's a Real-Time Example based on Dynamic Stacks to INCREASE ARRAY SIZE at Run-Time

File-name: DStack.java

public class DStack {
private int stck[];
int tos;

void Init_Stck(int size) {
    stck=new int[size];
    tos=-1;
}
int Change_Stck(int size){
    return stck[size];
}

public void push(int item){
    if(tos==stck.length-1){
        int temp[]=new int[stck.length+1];
        for(int i=0;i<stck.length;i++)temp[i]=stck[i];
        stck=temp;
        stck[++tos]=item;
    }
    else
        stck[++tos]=item;
}
public int pop(){
    if(tos<0){
        System.out.println("Stack Underflow");
        return 0;
    }
    else return stck[tos--];
}

public void display(){
    for(int x=0;x<stck.length;x++){
        System.out.print(stck[x]+" ");
    }
    System.out.println();
}

}

File-name: Exec.java
(with the main class)

import java.util.*;
public class Exec {

private static Scanner in;

public static void main(String[] args) {
    in = new Scanner(System.in);
    int option,item,i=1;
    DStack obj=new DStack();
    obj.Init_Stck(1);
    do{
        System.out.println();
        System.out.println("--MENU--");
        System.out.println("1. Push a Value in The Stack");
        System.out.println("2. Pop a Value from the Stack");
        System.out.println("3. Display Stack");
        System.out.println("4. Exit");
        option=in.nextInt();
        switch(option){
        case 1:
            System.out.println("Enter the Value to be Pushed");
            item=in.nextInt();
            obj.push(item);
            break;
        case 2:
            System.out.println("Popped Item: "+obj.pop());
            obj.Change_Stck(obj.tos);
            break;
        case 3:
            System.out.println("Displaying...");
            obj.display();
            break;
        case 4:
            System.out.println("Exiting...");
            i=0;
            break;
        default:
            System.out.println("Enter a Valid Value");

        }
    }while(i==1);

}

}

Hope this solves your query.

What is the difference between static_cast<> and C style casting?

static_cast checks at compile time that conversion is not between obviously incompatible types. Contrary to dynamic_cast, no check for types compatibility is done at run time. Also, static_cast conversion is not necessarily safe.

static_cast is used to convert from pointer to base class to pointer to derived class, or between native types, such as enum to int or float to int.

The user of static_cast must make sure that the conversion is safe.

The C-style cast does not perform any check, either at compile or at run time.

SQL Server : Transpose rows to columns

Another option that may be suitable in this situation is using XML

The XML option to transposing rows into columns is basically an optimal version of the PIVOT in that it addresses the dynamic column limitation.

The XML version of the script addresses this limitation by using a combination of XML Path, dynamic T-SQL and some built-in functions (i.e. STUFF, QUOTENAME).

Vertical expansion

Similar to the PIVOT and the Cursor, newly added policies are able to be retrieved in the XML version of the script without altering the original script.

Horizontal expansion

Unlike the PIVOT, newly added documents can be displayed without altering the script.

Performance breakdown

In terms of IO, the statistics of the XML version of the script is almost similar to the PIVOT – the only difference is that the XML has a second scan of dtTranspose table but this time from a logical read – data cache.

You can find some more about these solutions (including some actual T-SQL exmaples) in this article: https://www.sqlshack.com/multiple-options-to-transposing-rows-into-columns/

VBoxManage: error: Failed to create the host-only adapter

My solution

System Preferences -> System Security Privacy -> Allow oracle.xxxx; then reinstalling the virtualBox.

SQL Server stored procedure Nullable parameter

You can/should set your parameter to value to DBNull.Value;

if (variable == "")
{
     cmd.Parameters.Add("@Param", SqlDbType.VarChar, 500).Value = DBNull.Value;
}
else
{
     cmd.Parameters.Add("@Param", SqlDbType.VarChar, 500).Value = variable;
}

Or you can leave your server side set to null and not pass the param at all.

In Node.js, how do I turn a string to a json?

use the JSON function >

JSON.parse(theString)

twig: IF with multiple conditions

If I recall correctly Twig doesn't support || and && operators, but requires or and and to be used respectively. I'd also use parentheses to denote the two statements more clearly although this isn't technically a requirement.

{%if ( fields | length > 0 ) or ( trans_fields | length > 0 ) %}

Expressions

Expressions can be used in {% blocks %} and ${ expressions }.

Operator    Description
==          Does the left expression equal the right expression?
+           Convert both arguments into a number and add them.
-           Convert both arguments into a number and substract them.
*           Convert both arguments into a number and multiply them.
/           Convert both arguments into a number and divide them.
%           Convert both arguments into a number and calculate the rest of the integer division.
~           Convert both arguments into a string and concatenate them.
or          True if the left or the right expression is true.
and         True if the left and the right expression is true.
not         Negate the expression.

For more complex operations, it may be best to wrap individual expressions in parentheses to avoid confusion:

{% if (foo and bar) or (fizz and (foo + bar == 3)) %}

Quick-and-dirty way to ensure only one instance of a shell script is running at a time

I use a simple approach that handles stale lock files.

Note that some of the above solutions that store the pid, ignore the fact that the pid can wrap around. So - just checking if there is a valid process with the stored pid is not enough, especially for long running scripts.

I use noclobber to make sure only one script can open and write to the lock file at one time. Further, I store enough information to uniquely identify a process in the lockfile. I define the set of data to uniquely identify a process to be pid,ppid,lstart.

When a new script starts up, if it fails to create the lock file, it then verifies that the process that created the lock file is still around. If not, we assume the original process died an ungraceful death, and left a stale lock file. The new script then takes ownership of the lock file, and all is well the world, again.

Should work with multiple shells across multiple platforms. Fast, portable and simple.

#!/usr/bin/env sh
# Author: rouble

LOCKFILE=/var/tmp/lockfile #customize this line

trap release INT TERM EXIT

# Creates a lockfile. Sets global variable $ACQUIRED to true on success.
# 
# Returns 0 if it is successfully able to create lockfile.
acquire () {
    set -C #Shell noclobber option. If file exists, > will fail.
    UUID=`ps -eo pid,ppid,lstart $$ | tail -1`
    if (echo "$UUID" > "$LOCKFILE") 2>/dev/null; then
        ACQUIRED="TRUE"
        return 0
    else
        if [ -e $LOCKFILE ]; then 
            # We may be dealing with a stale lock file.
            # Bring out the magnifying glass. 
            CURRENT_UUID_FROM_LOCKFILE=`cat $LOCKFILE`
            CURRENT_PID_FROM_LOCKFILE=`cat $LOCKFILE | cut -f 1 -d " "`
            CURRENT_UUID_FROM_PS=`ps -eo pid,ppid,lstart $CURRENT_PID_FROM_LOCKFILE | tail -1`
            if [ "$CURRENT_UUID_FROM_LOCKFILE" == "$CURRENT_UUID_FROM_PS" ]; then 
                echo "Script already running with following identification: $CURRENT_UUID_FROM_LOCKFILE" >&2
                return 1
            else
                # The process that created this lock file died an ungraceful death. 
                # Take ownership of the lock file.
                echo "The process $CURRENT_UUID_FROM_LOCKFILE is no longer around. Taking ownership of $LOCKFILE"
                release "FORCE"
                if (echo "$UUID" > "$LOCKFILE") 2>/dev/null; then
                    ACQUIRED="TRUE"
                    return 0
                else
                    echo "Cannot write to $LOCKFILE. Error." >&2
                    return 1
                fi
            fi
        else
            echo "Do you have write permissons to $LOCKFILE ?" >&2
            return 1
        fi
    fi
}

# Removes the lock file only if this script created it ($ACQUIRED is set), 
# OR, if we are removing a stale lock file (first parameter is "FORCE") 
release () {
    #Destroy lock file. Take no prisoners.
    if [ "$ACQUIRED" ] || [ "$1" == "FORCE" ]; then
        rm -f $LOCKFILE
    fi
}

# Test code
# int main( int argc, const char* argv[] )
echo "Acquring lock."
acquire
if [ $? -eq 0 ]; then 
    echo "Acquired lock."
    read -p "Press [Enter] key to release lock..."
    release
    echo "Released lock."
else
    echo "Unable to acquire lock."
fi

Handling back button in Android Navigation Component

Here is solution that should do what you want, but i think it is a bad solution, because it is going against Android Navigation component idea(letting the android handle the navigation).

Override "onBackPressed" inside your activity

override fun onBackPressed() {
    when(NavHostFragment.findNavController(nav_host_fragment).currentDestination.id) {
        R.id.fragment2-> {
            val dialog=AlertDialog.Builder(this).setMessage("Hello").setPositiveButton("Ok", DialogInterface.OnClickListener { dialogInterface, i ->
                finish()
            }).show()
        }
        else -> {
            super.onBackPressed()
        }
    }
}

how to get login option for phpmyadmin in xampp

Step 1:

Locate phpMyAdmin installation path.

Step 2:

Open phpMyAdmin/config.inc.php in your favourite text editor. Copy config.sample.inc.php to config.inc.php if it's missing.

Step 3:

Search for $cfg['Servers'][$i]['auth_type'] = 'config';

Replace it with $cfg['Servers'][$i]['auth_type'] = 'cookie';

LINQ - Left Join, Group By, and Count

 (from p in context.ParentTable     
  join c in context.ChildTable 
    on p.ParentId equals c.ChildParentId into j1 
  from j2 in j1.DefaultIfEmpty() 
     select new { 
          ParentId = p.ParentId,
         ChildId = j2==null? 0 : 1 
      })
   .GroupBy(o=>o.ParentId) 
   .Select(o=>new { ParentId = o.key, Count = o.Sum(p=>p.ChildId) })

Computational complexity of Fibonacci Sequence

It is simple to calculate by diagramming function calls. Simply add the function calls for each value of n and look at how the number grows.

The Big O is O(Z^n) where Z is the golden ratio or about 1.62.

Both the Leonardo numbers and the Fibonacci numbers approach this ratio as we increase n.

Unlike other Big O questions there is no variability in the input and both the algorithm and implementation of the algorithm are clearly defined.

There is no need for a bunch of complex math. Simply diagram out the function calls below and fit a function to the numbers.

Or if you are familiar with the golden ratio you will recognize it as such.

This answer is more correct than the accepted answer which claims that it will approach f(n) = 2^n. It never will. It will approach f(n) = golden_ratio^n.

2 (2 -> 1, 0)

4 (3 -> 2, 1) (2 -> 1, 0)

8 (4 -> 3, 2) (3 -> 2, 1) (2 -> 1, 0)
            (2 -> 1, 0)


14 (5 -> 4, 3) (4 -> 3, 2) (3 -> 2, 1) (2 -> 1, 0)
            (2 -> 1, 0)

            (3 -> 2, 1) (2 -> 1, 0)

22 (6 -> 5, 4)
            (5 -> 4, 3) (4 -> 3, 2) (3 -> 2, 1) (2 -> 1, 0)
                        (2 -> 1, 0)

                        (3 -> 2, 1) (2 -> 1, 0)

            (4 -> 3, 2) (3 -> 2, 1) (2 -> 1, 0)
                        (2 -> 1, 0)

How can I return an empty IEnumerable?

I think the simplest way would be

 return new Friend[0];

The requirements of the return are merely that the method return an object which implements IEnumerable<Friend>. The fact that under different circumstances you return two different kinds of objects is irrelevant, as long as both implement IEnumerable.

How to Get Element By Class in JavaScript?

I assume this was not a valid option when this was originally asked, but you can now use document.getElementsByClassName('');. For example:

var elements = document.getElementsByClassName(names); // or:
var elements = rootElement.getElementsByClassName(names);

See the MDN documentation for more.

How to get the ASCII value of a character

To get the ASCII code of a character, you can use the ord() function.

Here is an example code:

value = input("Your value here: ")
list=[ord(ch) for ch in value]
print(list)

Output:

Your value here: qwerty
[113, 119, 101, 114, 116, 121]

How to print something when running Puppet client?

You can run the client like this ...

puppet agent --test --debug --noop

with that command you get all the output you can get.

excerpt puppet agent help

* --test:
  Enable the most common options used for testing. These are 'onetime',
  'verbose', 'ignorecache', 'no-daemonize', 'no-usecacheonfailure',
  'detailed-exitcodes', 'no-splay', and 'show_diff'.

NOTE: No need to include --verbose when you use the --test|-t switch, it implies the --verbose as well.

Set a cookie to never expire

Can't you just say a never ending loop, cookie expires as current date + 1 so it never hits the date it's supposed to expire on because it's always tomorrow? A bit overkill but just saying.

How to pass data between fragments

If you use Roboguice you can use the EventManager in Roboguice to pass data around without using the Activity as an interface. This is quite clean IMO.

If you're not using Roboguice you can use Otto too as a event bus: http://square.github.com/otto/

Update 20150909: You can also use Green Robot Event Bus or even RxJava now too. Depends on your use case.

Position DIV relative to another DIV?

You want to use position: absolute while inside the other div.

DEMO

Selected value for JSP drop down using JSTL

In HTML, the selected option is represented by the presence of the selected attribute on the <option> element like so:

<option ... selected>...</option>

Or if you're HTML/XHTML strict:

<option ... selected="selected">...</option>

Thus, you just have to let JSP/EL print it conditionally. Provided that you've prepared the selected department as follows:

request.setAttribute("selectedDept", selectedDept);

then this should do:

<select name="department">
    <c:forEach var="item" items="${dept}">
        <option value="${item.key}" ${item.key == selectedDept ? 'selected="selected"' : ''}>${item.value}</option>
    </c:forEach>
</select>

How to disable the back button in the browser using JavaScript

You can't, and you shouldn't.

Every other approach / alternative will only cause really bad user engagement.

That's my opinion.

How to check if a row exists in MySQL? (i.e. check if an email exists in MySQL)

The following are tried, tested and proven methods to check if a row exists.

(Some of which I use myself, or have used in the past).

Edit: I made an previous error in my syntax where I used mysqli_query() twice. Please consult the revision(s).

I.e.:

if (!mysqli_query($con,$query)) which should have simply read as if (!$query).

I apologize for overlooking that mistake.

Side note: Both '".$var."' and '$var' do the same thing. You can use either one, both are valid syntax.

Here are the two edited queries:

$query = mysqli_query($con, "SELECT * FROM emails WHERE email='".$email."'");

    if (!$query)
    {
        die('Error: ' . mysqli_error($con));
    }

if(mysqli_num_rows($query) > 0){

    echo "email already exists";

}else{

    // do something

}

and in your case:

$query = mysqli_query($dbl, "SELECT * FROM `tblUser` WHERE email='".$email."'");

    if (!$query)
    {
        die('Error: ' . mysqli_error($dbl));
    }

if(mysqli_num_rows($query) > 0){

    echo "email already exists";

}else{

    // do something

}

You can also use mysqli_ with a prepared statement method:

$query = "SELECT `email` FROM `tblUser` WHERE email=?";

if ($stmt = $dbl->prepare($query)){

        $stmt->bind_param("s", $email);

        if($stmt->execute()){
            $stmt->store_result();

            $email_check= "";         
            $stmt->bind_result($email_check);
            $stmt->fetch();

            if ($stmt->num_rows == 1){

            echo "That Email already exists.";
            exit;

            }
        }
    }

Or a PDO method with a prepared statement:

<?php
$email = $_POST['email'];

$mysql_hostname = 'xxx';
$mysql_username = 'xxx';
$mysql_password = 'xxx';
$mysql_dbname = 'xxx';

try {
$conn= new PDO("mysql:host=$mysql_hostname;dbname=$mysql_dbname", $mysql_username, $mysql_password); 
     $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
     exit( $e->getMessage() );
}

// assuming a named submit button
if(isset($_POST['submit']))
    {

        try {
            $stmt = $conn->prepare('SELECT `email` FROM `tblUser` WHERE email = ?');
            $stmt->bindParam(1, $_POST['email']); 
            $stmt->execute();
            while($row = $stmt->fetch(PDO::FETCH_ASSOC)) {

            }
        }
        catch(PDOException $e) {
            echo 'ERROR: ' . $e->getMessage();
        }

    if($stmt->rowCount() > 0){
        echo "The record exists!";
    } else {
        echo "The record is non-existant.";
    }


    }
?>

Prepared statements are best to be used to help protect against an SQL injection.

N.B.:

When dealing with forms and POST arrays as used/outlined above, make sure that the POST arrays contain values, that a POST method is used for the form and matching named attributes for the inputs.

FYI: Forms default to a GET method if not explicity instructed.

Note: <input type = "text" name = "var"> - $_POST['var'] match. $_POST['Var'] no match.

POST arrays are case-sensitive.

Consult:

http://php.net/manual/en/tutorial.forms.php

Error checking references:

Please note that MySQL APIs do not intermix, in case you may be visiting this Q&A and you're using mysql_ to connect with (and querying with).

You must use the same one from connecting to querying.

Consult the following about this:

Can I mix MySQL APIs in PHP?

If you are using the mysql_ API and have no choice to work with it, then consult the following Q&A on Stack:

MySql php: check if Row exists

The mysql_* functions are deprecated and will be removed from future PHP releases.

It's time to step into the 21st century.

You can also add a UNIQUE constraint to (a) row(s).

References:

Convert string to int array using LINQ

    public static int[] ConvertArray(string[] arrayToConvert)
    {
        int[] resultingArray = new int[arrayToConvert.Length];

        int itemValue;

        resultingArray = Array.ConvertAll<string, int>
            (
                arrayToConvert, 
                delegate(string intParameter) 
                {
                    int.TryParse(intParameter, out itemValue);
                    return itemValue;
                }
            );

        return resultingArray;
    }

Reference:

http://codepolice.net/convert-string-array-to-int-array-and-vice-versa-in-c/

How to alter a column's data type in a PostgreSQL table?

Cool @derek-kromm, Your answer is accepted and correct, But I am wondering if we need to alter more than the column. Here is how we can do.

ALTER TABLE tbl_name 
ALTER COLUMN col_name TYPE varchar (11), 
ALTER COLUMN col_name2 TYPE varchar (11),
ALTER COLUMN col_name3 TYPE varchar (11);

Documentation

Cheers!! Read Simple Write Simple

What does 'index 0 is out of bounds for axis 0 with size 0' mean?

In numpy, index and dimension numbering starts with 0. So axis 0 means the 1st dimension. Also in numpy a dimension can have length (size) 0. The simplest case is:

In [435]: x = np.zeros((0,), int)
In [436]: x
Out[436]: array([], dtype=int32)
In [437]: x[0]
...
IndexError: index 0 is out of bounds for axis 0 with size 0

I also get it if x = np.zeros((0,5), int), a 2d array with 0 rows, and 5 columns.

So someplace in your code you are creating an array with a size 0 first axis.

When asking about errors, it is expected that you tell us where the error occurs.

Also when debugging problems like this, the first thing you should do is print the shape (and maybe the dtype) of the suspected variables.

Applied to `pandas`

The same error can occur for those using pandas, when sending a Series or DataFrame to a numpy.array, as with the following:
- pandas.Series.values or pandas.Series.to_numpy() or pandas.Series.array
- pandas.DataFrame.values or pandas.DataFrame.to_numpy()

Resolving the error:

Use a try-except block
Verify the size of the array is not 0
- if x.size != 0:

Adding system header search path to Xcode

To use quotes just for completeness.

"/Users/my/work/a project with space"/**

If not recursive, remove the /**

Basic Apache commands for a local Windows machine

For frequent uses of this command I found it easy to add the location of C:\xampp\apache\bin to the PATH. Use whatever directory you have this installed in.

Then you can run from any directory in command line:

httpd -k restart

The answer above that suggests httpd -k -restart is actually a typo. You can see the commands by running httpd /?

Populate XDocument from String

You can use XDocument.Parse(string) instead of Load(string).

What is the difference between Visual Studio Express 2013 for Windows and Visual Studio Express 2013 for Windows Desktop?

Visual Studio for Windows Apps is meant to be used to build Windows Store Apps using HTML & Javascript or WinRT and XAML. These can also run on the Windows tablet that run Windows RT.

Visual Studio for Windows Desktop is meant to build applications using Windows Forms or Windows Presentation Foundation, these can run on Windows 8.1 on a normal desktop or on a tablet device like the Surface Pro in desktop mode (like a classic windows application).

Auto-indent spaces with C in vim?

Simply run:

user@host:~ $ echo set autoindent >> .vimrc

.gitignore for Visual Studio Projects and Solutions

Added InstallShield ignores for the build deployment. InstallShield is the new direction Microsoft is headed over Visual Studio Installer, so we've started using it on all new projects. This added line removes the SingleImage installation files. Other InstallShield types may include DVD distribution among others. You may want to add those directory names or just [Ee]xpress/ to prevent any InstallShield LE deployment files from getting into the repo.

Here is our .gitignore for VS2010 C# projects using Install Shield LE with SingleImage deployments for the installer:

#OS junk files
[Tt]humbs.db
*.DS_Store

#Visual Studio files
*.[Oo]bj
*.exe
*.pdb
*.user
*.aps
*.pch
*.vspscc
*.vssscc
*_i.c
*_p.c
*.ncb
*.suo
*.tlb
*.tlh
*.bak
*.[Cc]ache
*.ilk
*.log
*.lib
*.sbr
*.sdf
ipch/
obj/
[Bb]in
[Dd]ebug*/
[Rr]elease*/
Ankh.NoLoad

#InstallShield
[Ss]ingle[Ii]mage/
[Dd][Vv][Dd]-5/
[Ii]nterm/

#Tooling
_ReSharper*/
*.resharper
[Tt]est[Rr]esult*

#Project files
[Bb]uild/

#Subversion files
.svn

# Office Temp Files
~$*

Convert .pfx to .cer

the simple way I believe is to import it then export it, using the certificate manager in Windows Management Console.

Send JSON via POST in C# and Receive the JSON returned?

You can build your HttpContent using the combination of JObject to avoid and JProperty and then call ToString() on it when building the StringContent:

        /*{
          "agent": {                             
            "name": "Agent Name",                
            "version": 1                                                          
          },
          "username": "Username",                                   
          "password": "User Password",
          "token": "xxxxxx"
        }*/

        JObject payLoad = new JObject(
            new JProperty("agent", 
                new JObject(
                    new JProperty("name", "Agent Name"),
                    new JProperty("version", 1)
                    ),
                new JProperty("username", "Username"),
                new JProperty("password", "User Password"),
                new JProperty("token", "xxxxxx")    
                )
            );

        using (HttpClient client = new HttpClient())
        {
            var httpContent = new StringContent(payLoad.ToString(), Encoding.UTF8, "application/json");

            using (HttpResponseMessage response = await client.PostAsync(requestUri, httpContent))
            {
                response.EnsureSuccessStatusCode();
                string responseBody = await response.Content.ReadAsStringAsync();
                return JObject.Parse(responseBody);
            }
        }

Circular dependency in Spring

The Spring reference manual explains how circular dependencies are resolved. The beans are instantiated first, then injected into each other.

Consider this class:

package mypackage;

public class A {

    public A() {
        System.out.println("Creating instance of A");
    }

    private B b;

    public void setB(B b) {
        System.out.println("Setting property b of A instance");
        this.b = b;
    }

}

And a similar class B:

package mypackage;

public class B {

    public B() {
        System.out.println("Creating instance of B");
    }

    private A a;

    public void setA(A a) {
        System.out.println("Setting property a of B instance");
        this.a = a;
    }

}

If you then had this configuration file:

<bean id="a" class="mypackage.A">
    <property name="b" ref="b" />
</bean>

<bean id="b" class="mypackage.B">
    <property name="a" ref="a" />
</bean>

You would see the following output when creating a context using this configuration:

Creating instance of A
Creating instance of B
Setting property a of B instance
Setting property b of A instance

Note that when a is injected into b, a is not yet fully initialised.

Is it possible to set a number to NaN or infinity?

Is it possible to set a number to NaN or infinity?

Yes, in fact there are several ways. A few work without any imports, while others require import, however for this answer I'll limit the libraries in the overview to standard-library and NumPy (which isn't standard-library but a very common third-party library).

The following table summarizes the ways how one can create a not-a-number or a positive or negative infinity float:

+-------------------------------------------------------------------+
¦   result ¦ NaN          ¦ Infinity           ¦ -Infinity          ¦
¦ module   ¦              ¦                    ¦                    ¦
¦----------+--------------+--------------------+--------------------¦
¦ built-in ¦ float("nan") ¦ float("inf")       ¦ -float("inf")      ¦
¦          ¦              ¦ float("infinity")  ¦ -float("infinity") ¦
¦          ¦              ¦ float("+inf")      ¦ float("-inf")      ¦
¦          ¦              ¦ float("+infinity") ¦ float("-infinity") ¦
+----------+--------------+--------------------+--------------------¦
¦ math     ¦ math.nan     ¦ math.inf           ¦ -math.inf          ¦
+----------+--------------+--------------------+--------------------¦
¦ cmath    ¦ cmath.nan    ¦ cmath.inf          ¦ -cmath.inf         ¦
+----------+--------------+--------------------+--------------------¦
¦ numpy    ¦ numpy.nan    ¦ numpy.PINF         ¦ numpy.NINF         ¦
¦          ¦ numpy.NaN    ¦ numpy.inf          ¦ -numpy.inf         ¦
¦          ¦ numpy.NAN    ¦ numpy.infty        ¦ -numpy.infty       ¦
¦          ¦              ¦ numpy.Inf          ¦ -numpy.Inf         ¦
¦          ¦              ¦ numpy.Infinity     ¦ -numpy.Infinity    ¦
+-------------------------------------------------------------------+

A couple remarks to the table:

The float constructor is actually case-insensitive, so you can also use float("NaN") or float("InFiNiTy").
The cmath and numpy constants return plain Python float objects.
The numpy.NINF is actually the only constant I know of that doesn't require the -.

It is possible to create complex NaN and Infinity with complex and cmath:

+------------------------------------------------------------------------------------------+
¦   result ¦ NaN+0j         ¦ 0+NaNj          ¦ Inf+0j              ¦ 0+Infj               ¦
¦ module   ¦                ¦                 ¦                     ¦                      ¦
¦----------+----------------+-----------------+---------------------+----------------------¦
¦ built-in ¦ complex("nan") ¦ complex("nanj") ¦ complex("inf")      ¦ complex("infj")      ¦
¦          ¦                ¦                 ¦ complex("infinity") ¦ complex("infinityj") ¦
+----------+----------------+-----------------+---------------------+----------------------¦
¦ cmath    ¦ cmath.nan ¹    ¦ cmath.nanj      ¦ cmath.inf ¹         ¦ cmath.infj           ¦
+------------------------------------------------------------------------------------------+

The options with ¹ return a plain float, not a complex.

is there any function to check whether a number is infinity or not?

Yes there is - in fact there are several functions for NaN, Infinity, and neither Nan nor Inf. However these predefined functions are not built-in, they always require an import:

+--------------------------------------------------------------+
¦      for ¦ NaN         ¦ Infinity or    ¦ not NaN and        ¦
¦          ¦             ¦ -Infinity      ¦ not Infinity and   ¦
¦ module   ¦             ¦                ¦ not -Infinity      ¦
¦----------+-------------+----------------+--------------------¦
¦ math     ¦ math.isnan  ¦ math.isinf     ¦ math.isfinite      ¦
+----------+-------------+----------------+--------------------¦
¦ cmath    ¦ cmath.isnan ¦ cmath.isinf    ¦ cmath.isfinite     ¦
+----------+-------------+----------------+--------------------¦
¦ numpy    ¦ numpy.isnan ¦ numpy.isinf    ¦ numpy.isfinite     ¦
+--------------------------------------------------------------+

Again a couple of remarks:

The cmath and numpy functions also work for complex objects, they will check if either real or imaginary part is NaN or Infinity.
The numpy functions also work for numpy arrays and everything that can be converted to one (like lists, tuple, etc.)
There are also functions that explicitly check for positive and negative infinity in NumPy: numpy.isposinf and numpy.isneginf.
Pandas offers two additional functions to check for NaN: pandas.isna and pandas.isnull (but not only NaN, it matches also None and NaT)

Even though there are no built-in functions, it would be easy to create them yourself (I neglected type checking and documentation here):

def isnan(value):
    return value != value  # NaN is not equal to anything, not even itself

infinity = float("infinity")

def isinf(value):
    return abs(value) == infinity 

def isfinite(value):
    return not (isnan(value) or isinf(value))

To summarize the expected results for these functions (assuming the input is a float):

+----------------------------------------------------------------------+
¦          input ¦ NaN   ¦ Infinity   ¦ -Infinity   ¦ something else   ¦
¦ function       ¦       ¦            ¦             ¦                  ¦
¦----------------+-------+------------+-------------+------------------¦
¦ isnan          ¦ True  ¦ False      ¦ False       ¦ False            ¦
+----------------+-------+------------+-------------+------------------¦
¦ isinf          ¦ False ¦ True       ¦ True        ¦ False            ¦
+----------------+-------+------------+-------------+------------------¦
¦ isfinite       ¦ False ¦ False      ¦ False       ¦ True             ¦
+----------------------------------------------------------------------+

Is it possible to set an element of an array to NaN in Python?

In a list it's no problem, you can always include NaN (or Infinity) there:

>>> [math.nan, math.inf, -math.inf, 1]  # python list
[nan, inf, -inf, 1]

However if you want to include it in an array (for example array.array or numpy.array) then the type of the array must be float or complex because otherwise it will try to downcast it to the arrays type!

>>> import numpy as np
>>> float_numpy_array = np.array([0., 0., 0.], dtype=float)
>>> float_numpy_array[0] = float("nan")
>>> float_numpy_array
array([nan,  0.,  0.])

>>> import array
>>> float_array = array.array('d', [0, 0, 0])
>>> float_array[0] = float("nan")
>>> float_array
array('d', [nan, 0.0, 0.0])

>>> integer_numpy_array = np.array([0, 0, 0], dtype=int)
>>> integer_numpy_array[0] = float("nan")
ValueError: cannot convert float NaN to integer

How to convert an array of key-value tuples into an object

Update June 2020

ECMAScript 2021 brings Object.fromEntries which does exactly the requirement:

_x000D_

const array =    [ [ 'cardType', 'iDEBIT' ],
      [ 'txnAmount', '17.64' ],
      [ 'txnId', '20181' ],
      [ 'txnType', 'Purchase' ],
      [ 'txnDate', '2015/08/13 21:50:04' ],
      [ 'respCode', '0' ],
      [ 'isoCode', '0' ],
      [ 'authCode', '' ],
      [ 'acquirerInvoice', '0' ],
      [ 'message', '' ],
      [ 'isComplete', 'true' ],
      [ 'isTimeout', 'false' ] ];
      
const obj = Object.fromEntries(array);
console.log(obj);

_x000D_

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/fromEntries

This will do it:

_x000D_

const array =    [ [ 'cardType', 'iDEBIT' ],
      [ 'txnAmount', '17.64' ],
      [ 'txnId', '20181' ],
      [ 'txnType', 'Purchase' ],
      [ 'txnDate', '2015/08/13 21:50:04' ],
      [ 'respCode', '0' ],
      [ 'isoCode', '0' ],
      [ 'authCode', '' ],
      [ 'acquirerInvoice', '0' ],
      [ 'message', '' ],
      [ 'isComplete', 'true' ],
      [ 'isTimeout', 'false' ] ];
    
var obj = {};
array.forEach(function(data){
    obj[data[0]] = data[1]
});
console.log(obj);

_x000D_

C programming in Visual Studio

Yes, you very well can learn C using Visual Studio.

Visual Studio comes with its own C compiler, which is actually the C++ compiler. Just use the .c file extension to save your source code.

You don't have to be using the IDE to compile C. You can write the source in Notepad, and compile it in command line using Developer Command Prompt which comes with Visual Studio.

Open the Developer Command Prompt, enter the directory you are working in, use the cl command to compile your C code.

For example, cl helloworld.c compiles a file named helloworld.c.

Refer this for more information: Walkthrough: Compiling a C Program on the Command Line

Hope this helps

A circular reference was detected while serializing an object of type 'SubSonic.Schema .DatabaseColumn'.

Using Newtonsoft.Json: In your Global.asax Application_Start method add this line:

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;

syntax for creating a dictionary into another dictionary in python

dict1 = {}

dict1['dict2'] = {}

print dict1

>>> {'dict2': {},}

this is commonly known as nesting iterators into other iterators I think

JSONP call showing "Uncaught SyntaxError: Unexpected token : "

Working fiddle:

http://jsfiddle.net/repjt/

$.ajax({
    url: 'https://api.flightstats.com/flex/schedules/rest/v1/jsonp/flight/AA/100/departing/2013/10/4?appId=19d57e69&appKey=e0ea60854c1205af43fd7b1203005d59',
    dataType: 'JSONP',
    jsonpCallback: 'callback',
    type: 'GET',
    success: function (data) {
        console.log(data);
    }
});

I had to manually set the callback to callback, since that's all the remote service seems to support. I also changed the url to specify that I wanted jsonp.

split string only on first instance of specified character

Mark F's solution is awesome but it's not supported by old browsers. Kennebec's solution is awesome and supported by old browsers but doesn't support regex.

So, if you're looking for a solution that splits your string only once, that is supported by old browsers and supports regex, here's my solution:

_x000D_

String.prototype.splitOnce = function(regex)_x000D_
{_x000D_
    var match = this.match(regex);_x000D_
    if(match)_x000D_
    {_x000D_
        var match_i = this.indexOf(match[0]);_x000D_
        _x000D_
        return [this.substring(0, match_i),_x000D_
        this.substring(match_i + match[0].length)];_x000D_
    }_x000D_
    else_x000D_
    { return [this, ""]; }_x000D_
}_x000D_
_x000D_
var str = "something/////another thing///again";_x000D_
_x000D_
alert(str.splitOnce(/\/+/)[1]);

_x000D_

How to convert an address into a Google Maps Link (NOT MAP)

The best way is to use this line:

var mapUrl = "http://maps.google.com/maps?f=q&amp;source=s_q&amp;hl=en&amp;geocode=&amp;q=16900+North+Bay+Road,+Sunny+Isles+Beach,+FL+33160&amp;aq=0&amp;sll=37.0625,-95.677068&amp;sspn=61.282355,146.513672&amp;ie=UTF8&amp;hq=&amp;hnear=16900+North+Bay+Road,+Sunny+Isles+Beach,+FL+33160&amp;spn=0.01628,0.025663&amp;z=14&amp;iwloc=A&amp;output=embed"

Remember to replace the first and second addresses when necessary.

You can look at work sample

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