Programs & Examples On #Dotfuscator

Dotfuscator provides application self-protection and obfuscation for any type of .NET app through a combination of binary obfuscation/hardening, detection, defense and alert controls. A lite version (Dotfuscator CE) is included inside Visual Studio.

.NET obfuscation tools/strategy

We have a multi tier app with an and winform interface that also supports remoting. I've had no problems with using any obfuscator with the exception of the encrypting type which generates a loader which can be problematic in all sorts of unexpected ways and just not worth it in my opinion. Actually my advice would be more along the lines of "Avoid encrypting loader type obfuscators like the plague". :)

In my experience any obfuscator will work fine with any aspect of .net including and remoting, you just have to become intimate with the settings and learn how far you can push it in which areas of your code. And take the time to attempt reverse engineering on what you get and see how it works with the various settings.

We used several over the years in our commercial apps and settled on Spices obfuscator from because the price is right, it does the job and they have good support though we really haven't needed the support in years anymore but to be honest I don't think it really matters which obfuscator you use, the issues and learning curve are all the same if you want to have it work properly with remoting and

As others have mentioned all you're really doing is the equivalent of a padlock, keeping otherwise honest people out and or making it harder to simply recompile an app.

Licensing is usually the key area for most people and you should definitely be using some kind of digitally signed certificate system for licensing anyway. Your biggest loss will come from casual sharing of licenses if you don't have a smart system in place, the people that break the licensing system were never going to buy in the first place.

It's really easy to take this too far and have a negative impact on your customers and your business, do what is simple and reasonable and then don't worry about it.

Integrity constraint violation: 1452 Cannot add or update a child row:

Maybe you have some rows in the table that you want to create de FK.

Run the migration with foreign_key_checks OFF Insert only those records that have corresponding id field in contents table.

Is there a cross-domain iframe height auto-resizer that works?

I have a script that drops in the iframe with it's content. It also makes sure that iFrameResizer exists (it injects it as a script) and then does the resizing.

I'll drop in a simplified example below.

// /js/embed-iframe-content.js

    // Note the id, we need to set this correctly on the script tag responsible for
    // requesting this file.
    var me = document.getElementById('my-iframe-content-loader-script-tag');

    function loadIFrame() {
        var ifrm = document.createElement('iframe'); = 'my-iframe-identifier';
        ifrm.setAttribute('src', ''); = '100%'; = 0;
        // we initially hide the iframe to avoid seeing the iframe resizing = 0;
        ifrm.onload = function () {
            // this will resize our iframe
            iFrameResize({ log: true }, '#my-iframe-identifier');
            // make our iframe visible
   = 1;

        me.insertAdjacentElement('afterend', ifrm);

    if (!window.iFrameResize) {
        // We first need to ensure we inject the js required to resize our iframe.

        var resizerScriptTag = document.createElement('script');
        resizerScriptTag.type = 'text/javascript';

        // IMPORTANT: insert the script tag before attaching the onload and setting the src.
        me.insertAdjacentElement('afterend', ifrm);

        // IMPORTANT: attach the onload before setting the src.
        resizerScriptTag.onload = loadIFrame;

        // This a CDN resource to get the iFrameResizer code.
        // NOTE: You must have the below "coupled" script hosted by the content that
        // is loaded within the iframe:
        //[email protected]/js/iframeResizer.contentWindow.min.js
        resizerScriptTag.src = '[email protected]/js/iframeResizer.min.js';
    } else {
        // Cool, the iFrameResizer exists so we can just load our iframe.

Then the iframe content can be injected anywhere within another page/site by using the script like so:


The iframe content will be injected below wherever you place the script tag.

Hope this is helpful to someone.

What is getattr() exactly and how do I use it?

I sometimes use getattr(..) to lazily initialise attributes of secondary importance just before they are used in the code.

Compare the following:

class Graph(object):
    def __init__(self):
        self.n_calls_to_plot = 0

    #A lot of code here

    def plot(self):
        self.n_calls_to_plot += 1

To this:

class Graph(object):
    def plot(self):
        self.n_calls_to_plot = 1 + getattr(self, "n_calls_to_plot", 0)

The advantage of the second way is that n_calls_to_plot only appears around the place in the code where it is used. This is good for readability, because (1) you can immediately see what value it starts with when reading how it's used, (2) it doesn't introduce a distraction into the __init__(..) method, which ideally should be about the conceptual state of the class, rather than some utility counter that is only used by one of the function's methods for technical reasons, such as optimisation, and has nothing to do with the meaning of the object.

How to retrieve data from sqlite database in android and display it in TextView

You are using getData() method as void.

You can not return values from void.

Converting dict to OrderedDict

Most of the time we go for OrderedDict when we required a custom order not a generic one like ASC etc.

Here is the proposed solution:

import collections
ship = {"NAME": "Albatross",

ship = collections.OrderedDict(ship)

print ship

new_dict = collections.OrderedDict()

print new_dict

This will be output:

OrderedDict([('PRICE', 250), ('HP', 50), ('NAME', 'Albatross'), ('BLASTERS', 13), ('THRUSTERS', 18)])
OrderedDict([('NAME', 'Albatross'), ('HP', 50), ('BLASTERS', 13), ('THRUSTERS', 18), ('PRICE', 250)])

Note: The new sorted dictionaries maintain their sort order when entries are deleted. But when new keys are added, the keys are appended to the end and the sort is not maintained.(official doc)

How to get Activity's content view?

How about

View view = Activity.getCurrentFocus();

How can I query a value in SQL Server XML column

  Roles.value('(/root/role)[1]', 'varchar(max)') like 'StringToSearchFor'

In case your column is not XML, you need to convert it. You can also use other syntax to query certain attributes of your XML data. Here is an example...

Let's suppose that data column has this:

<Utilities.CodeSystems.CodeSystemCodes iid="107" CodeSystem="2" Code="0001F" CodeTags="-19-"..../>

... and you only want the ones where CodeSystem = 2 then your query will be:

  CAST([data] as XML).value('(/Utilities.CodeSystems.CodeSystemCodes/@CodeSystem)[1]', 'varchar(max)') = '2'

These pages will show you more about how to query XML in T-SQL:

Querying XML fields using t-sql

Flattening XML Data in SQL Server


After playing with it a little bit more, I ended up with this amazing query that uses CROSS APPLY. This one will search every row (role) for the value you put in your like expression...

Given this table structure:

create table MyTable (Roles XML)

insert into MyTable values

We can query it like this:

select * from 

       pref.value('(text())[1]', 'varchar(32)') as RoleName
       MyTable CROSS APPLY

       Roles.nodes('/root/role') AS Roles(pref)
)  as Result

where RoleName like '%ga%'

You can check the SQL Fiddle here:!18/dc4d2/1/0

Eclipse error, "The selection cannot be launched, and there are no recent launches"

Eclipse can't work out what you want to run and since you've not run anything before, it can't try re-running that either.

Instead of clicking the green 'run' button, click the dropdown next to it and chose Run Configurations. On the Android tab, make sure it's set to your project. In the Target tab, set the tick box and options as appropriate to target your device. Then click Run. Keep an eye on your Console tab in Eclipse - that'll let you know what's going on. Once you've got your run configuration set, you can just hit the green 'run' button next time.

Sometimes getting everything to talk to your device can be problematic to begin with. Consider using an AVD (i.e. an emulator) as alternative, at least to begin with if you have problems. You can easily create one from the menu Window -> Android Virtual Device Manager within Eclipse.

To view the progress of your project being installed and started on your device, check the console. It's a panel within Eclipse with the tabs Problems/Javadoc/Declaration/Console/LogCat etc. It may be minimised - check the tray in the bottom right. Or just use Window/Show View/Console from the menu to make it come to the front. There are two consoles, Android and DDMS - there is a dropdown by its icon where you can switch.

Change some value inside the List<T>

I'd probably go with this (I know its not pure linq), keep a reference to the original list if you want to retain all items, and you should find the updated values are in there:

 foreach (var mc in list.Where(x => x.Name == "height"))  
     mc.Value = 30;

A project with an Output Type of Class Library cannot be started directly

I had a similar issue when trying to use the Experimental Instance of Visual Studio 2013. This was for a vsix project (Creating Snippets).

Solution was:

Right Click Project in Solution Explorer > Properties > Debug

Setting the Start Action to "Start external program" and using the following path:

C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\devenv.exe

This option was set to "Start project" which won't work for the application output type Class Library, which caused that same error.

Note: Yours may differ depending on how you installed VS.

Is there any way to specify a suggested filename when using data: URI?

Using service workers, this is finally possible in the truest sense.

  1. Create a fake URL. For example /saveAs/myPrettyName.jpg
  2. Use URL in <a href, <img src, url ), absolutely anything that can be done with a "real" URL.
  3. Inside the worker, catch the fetch event, and respond with the correct data.

The browser will now suggest myPrettyName.jpg even if the user opens the file in a new tab, and tries to save it there. It will be exactly as if the file had come from the server.

// In the service worker
self.addEventListener( 'fetch', function(e)
    if( e.request.url.startsWith( '/blobUri/' ) )
        // Logic to select correct dataUri, and return it as a Response
        e.respondWith( dataURLAsRequest );

how to run or install a *.jar file in windows?

Open up a command prompt and type java -jar jbpm-installer-3.2.7.jar

How can I view an old version of a file with Git?

In addition to Jim Hunziker's answer,

you can export the file from the revision as,

git show HEAD@{2013-02-25}:./fileInCurrentDirectory.txt > old_fileInCurrentDirectory.txt

Hope this helps :)

Bootstrap 4: Multilevel Dropdown Inside Navigation

Updated 2018

Here is another variation on the Bootstrap 4.1 Navbar with multi-level dropdown. This one uses minimal CSS for the submenu, and can be re-positioned as desired:

enter image description here

.dropdown-submenu {
  position: relative;

.dropdown-submenu .dropdown-menu {
  top: 0;
  left: 100%;
  margin-top: -1px;

jQuery to control display of submenus:

$('.dropdown-submenu > a').on("click", function(e) {
    var submenu = $(this);
    $('.dropdown-submenu .dropdown-menu').removeClass('show');'.dropdown-menu').addClass('show');

$('.dropdown').on("", function() {
    // hide any open menus when parent closes

See this answer for activating the Bootstrap 4 submenus on hover

Styling HTML email for Gmail

Use inline styles for everything. This site will convert your classes to inline styles:

Difference between DataFrame, Dataset, and RDD in Spark

Because DataFrame is weakly typed and developers aren't getting the benefits of the type system. For example, lets say you want to read something from SQL and run some aggregation on it:

val people ="...")
val department ="...")

people.filter("age > 30")
  .join(department, people("deptId") === department("id"))
  .groupBy(department("name"), "gender")
  .agg(avg(people("salary")), max(people("age")))

When you say people("deptId"), you're not getting back an Int, or a Long, you're getting back a Column object which you need to operate on. In languages with a rich type systems such as Scala, you end up losing all the type safety which increases the number of run-time errors for things that could be discovered at compile time.

On the contrary, DataSet[T] is typed. when you do:

val people: People = val people ="...").as[People]

You're actually getting back a People object, where deptId is an actual integral type and not a column type, thus taking advantage of the type system.

As of Spark 2.0, the DataFrame and DataSet APIs will be unified, where DataFrame will be a type alias for DataSet[Row].

Bulk Insert into Oracle database: Which is better: FOR Cursor loop or a simple Select?

A simple insert/select like your 2nd option is far preferable. For each insert in the 1st option you require a context switch from pl/sql to sql. Run each with trace/tkprof and examine the results.

If, as Michael mentions, your rollback cannot handle the statement then have your dba give you more. Disk is cheap, while partial results that come from inserting your data in multiple passes is potentially quite expensive. (There is almost no undo associated with an insert.)

Storing Data in MySQL as JSON

You can use this gist:

After installing it to the server (just need root privilege not super), you can do something like this:

select extract_json_value('{"a":["a","2"]}','(/a)')

It will return a 2 .You can return anything inside JSON by using this The good part is that it is support MySQL 5.1,5.2,5.6. And you do not need to install any binary on the server.

Based on old project common-schema, but it is still working today

Git remote branch deleted, but still it appears in 'branch -a'

git remote prune origin, as suggested in the other answer, will remove all such stale branches. That's probably what you'd want in most cases, but if you want to just remove that particular remote-tracking branch, you should do:

git branch -d -r origin/coolbranch

(The -r is easy to forget...)

-r in this case will "List or delete (if used with -d) the remote-tracking branches." according to the Git documentation found here:

Bad Request - Invalid Hostname IIS7

If working on local server or you haven't got domain name, delete "Host Name:" field. enter image description here

Python 3 string.join() equivalent?

There are method join for string objects:


Free Barcode API for .NET

Could the Barcode Rendering Framework at Codeplex GitHub be of help?

MVC 4 Razor adding input type date

I managed to do it by using the following code.

@Html.TextBoxFor(model => model.EndTime, new { type = "time" })

mysql: get record count between two date-time

select * from yourtable where created < now() and created > '2011-04-25 04:00:00'

Difference between parameter and argument

Generally, the parameters are what are used inside the function and the arguments are the values passed when the function is called. (Unless you take the opposite view — Wikipedia mentions alternative conventions when discussing parameters and arguments).

double sqrt(double x)
    return x;

void other(void)
     double two = sqrt(2.0);

Under my thesis, x is the parameter to sqrt() and 2.0 is the argument.

The terms are often used at least somewhat interchangeably.

Jquery in React is not defined

Isn't easier than doing like :

1- Install jquery in your project:

yarn add jquery

2- Import jquery and start playing with DOM:

import $ from 'jquery';

Copying text outside of Vim with set mouse=a enabled

In ESC mode, when set mouse=a, select the text using mouse. This would enable the visual mode in vim. Then you can press 'y' to yank the selected text and 'p' to paste it wherever you want. This happens only within vim.

Drawing in Java using Canvas

Why would the first way not work. Canvas object is created and the size is set and the grahpics are set. I always find this strange. Also if a class extends JComponent you can override the


and then shouldn't you be able to create and instance of the class inside of another class and then just call NewlycreateinstanceOfAnyClass.repaint();

I have tried this approach for some game programming I have been working and it doesn't seem to work the way I think that it should be.

Doug Hauf

accessing a variable from another class

I hope I'm understanding the problem correctly, but it looks like you don't have a reference back to your DrawFrame object from DrawCircle.

Try this:

Change your constructor signature for DrawCircle to take in a DrawFrame object. Within the constructor, set the class variable "d" to the DrawFrame object you just took in. Now add the getWidth/getHeight methods to DrawFrame as mentioned in previous answers. See if that allows you to get what you're looking for.

Your DrawCircle constructor should be changed to something like:

public DrawCircle(DrawFrame frame)
    d = frame;
    w = 400;
    h = 400;
    diBig = 300;
    diSmall = 10;
    maxRad = (diBig/2) - diSmall;
    xSq = 50;
    ySq = 50;
    xPoint = 200;
    yPoint = 200;

The last line of code in DrawFrame should look something like:

contentPane.add(new DrawCircle(this));

Then, try using d.getheight(), d.getWidth() and so on within DrawCircle. This assumes you still have those methods available on DrawFrame to access them, of course.

How to generate all permutations of a list?

A quite obvious way in my opinion might be also:

def permutList(l):
    if not l:
            return [[]]
    res = []
    for e in l:
            temp = l[:]
            res.extend([[e] + r for r in permutList(temp)])

    return res

Java: object to byte[] and byte[] to object converter (for Tokyo Cabinet)

You can use ObjectMapper

        ObjectMapper objectMapper = new ObjectMapper();
        ObjectClass object = objectMapper.readValue(data, ObjectClass.class);

How to add a changed file to an older (not last) commit in Git

To "fix" an old commit with a small change, without changing the commit message of the old commit, where OLDCOMMIT is something like 091b73a:

git add <my fixed files>
git commit --fixup=OLDCOMMIT
git rebase --interactive --autosquash OLDCOMMIT^

You can also use git commit --squash=OLDCOMMIT to edit the old commit message during rebase.

See documentation for git commit and git rebase. As always, when rewriting git history, you should only fixup or squash commits you have not yet published to anyone else (including random internet users and build servers).

Detailed explanation

  • git commit --fixup=OLDCOMMIT copies the OLDCOMMIT commit message and automatically prefixes fixup! so it can be put in the correct order during interactive rebase. (--squash=OLDCOMMIT does the same but prefixes squash!.)
  • git rebase --interactive will bring up a text editor (which can be configured) to confirm (or edit) the rebase instruction sequence. There is info for rebase instruction changes in the file; just save and quit the editor (:wq in vim) to continue with the rebase.
  • --autosquash will automatically put any --fixup=OLDCOMMIT commits in the correct order. Note that --autosquash is only valid when the --interactive option is used.
  • The ^ in OLDCOMMIT^ means it's a reference to the commit just before OLDCOMMIT. (OLDCOMMIT^ is the first parent of OLDCOMMIT.)

Optional automation

The above steps are good for verification and/or modifying the rebase instruction sequence, but it's also possible to skip/automate the interactive rebase text editor by:

Escape dot in a regex range

On this web page, I see that:

"Remember that the dot is not a metacharacter inside a character class, so we do not need to escape it with a backslash."

So I guess the escaping of it is unnecessary...

How to change owner of PostgreSql database?


See the Postgresql manual's entry on this for more details.

How to create a custom string representation for a class object?

class foo(object):
    def __str__(self):
        return "representation"
    def __unicode__(self):
        return u"representation"

CSS align images and text on same line

In this case you can use display:inline or inline-block.


img.likeordisklike {display:inline;vertical-align:middle;  }_x000D_
h4.liketext { color:#F00; display:inline;vertical-align:top;padding-left:10px; }
<img class='likeordislike' src='design/like.png'/><h4 class='liketext'>$likes</h4>_x000D_
<img class='likeordislike' src='design/dislike.png'/><h4 class='liketext'>$dislikes</h4>

Don't use float:left because again need to write one more clear line and its old method also..

Swift alert view with OK and Cancel: which button tapped?

var refreshAlert = UIAlertController(title: "Log Out", message: "Are You Sure to Log Out ? ", preferredStyle: UIAlertControllerStyle.Alert)

refreshAlert.addAction(UIAlertAction(title: "Confirm", style: .Default, handler: { (action: UIAlertAction!) in

refreshAlert.addAction(UIAlertAction(title: "Cancel", style: .Default, handler: { (action: UIAlertAction!) in

    refreshAlert .dismissViewControllerAnimated(true, completion: nil)


presentViewController(refreshAlert, animated: true, completion: nil)

How do I output text without a newline in PowerShell?

It may not be terribly elegant, but it does exactly what OP requested. Note that the ISE messes with StdOut, so there will be no output. In order to see this script work it can't be run within the ISE.

$strOutput="Enabling feature XYZ... "

Definitive way to trigger keypress events with jQuery

Slightly more concise now with jQuery 1.6+:

var e = jQuery.Event( 'keydown', { which: $.ui.keyCode.ENTER } );


(If you're not using jQuery UI, sub in the appropriate keycode instead.)

Jetty: HTTP ERROR: 503/ Service Unavailable

I had the same problem. I solved it by removing the line break from the xml file. I did


instead of ...


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;
     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.

Bootstrap Modal Backdrop Remaining

If after modal hide, faded background is remained and does not let you click any where you can forcefully remove those by using below piece of code.

First hide (all) your modal div elements.


Secondly remove 'modal-open' class from body and '.modal-backdrop' at the end of the page.


MySQL IF ELSEIF in select query

You have what you have used in stored procedures like this for reference, but they are not intended to be used as you have now. You can use IF as shown by duskwuff. But a Case statement is better for eyes. Like this:

select id, 
        WHEN qty_1 <= '23' THEN price
        WHEN '23' > qty_1 && qty_2 <= '23' THEN price_2
        WHEN '23' > qty_2 && qty_3 <= '23' THEN price_3
        WHEN '23' > qty_3 THEN price_4
        ELSE 1
    END) AS total
 from product;

This looks cleaner. I suppose you do not require the inner SELECT anyway..

"Could not find acceptable representation" using spring-boot-starter-web

In my case I was sending in correct object in ResponseEntity<>().

Correct :

@PostMapping(value = "/get-customer-details", produces = { MediaType.APPLICATION_JSON_VALUE })
public ResponseEntity<?> getCustomerDetails(@RequestBody String requestMessage) throws JSONException {
    JSONObject jsonObject = new JSONObject();
    jsonObject.put("customerId", "123");
    jsonObject.put("mobileNumber", "XXX-XXX-XXXX");
    return new ResponseEntity<>(jsonObject.toString(), HttpStatus.OK);

Incorrect :

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

Because, jsonObject's toString() method "Encodes the jsonObject as a compact JSON string". Therefore, Spring returns json string directly without any further serialization.

When we send jsonObject instead, Spring tries to serialize it based on produces method used in RequestMapping and fails due to it "Could not find acceptable representation".

$.ajax - dataType

(ps: the answer given by Nick Craver is incorrect)

contentType specifies the format of data being sent to the server as part of request(it can be sent as part of response too, more on that later).

dataType specifies the expected format of data to be received by the client(browser).

Both are not interchangable.

  • contentType is the header sent to the server, specifying the format of data(i.e the content of message body) being being to the server. This is used with POST and PUT requests. Usually when u send POST request, the message body comprises of passed in parameters like:


Sample request:

POST /search HTTP/1.1 
Content-Type: application/x-www-form-urlencoded 
<<other header>>



The last line above "name=sam&age=35" is the message body and contentType specifies it as application/x-www-form-urlencoded since we are passing the form parameters in the message body. However we aren't limited to just sending the parameters, we can send json, xml,... like this(sending different types of data is especially useful with RESTful web services):


Sample request:

POST /orders HTTP/1.1
Content-Type: application/xml
<<other header>>

   <date>December 22, 2008 06:56</date>


So the ContentType this time is: application/xml, cause that's what we are sending. The above examples showed sample request, similarly the response send from the server can also have the Content-Type header specifying what the server is sending like this:


sample response:

HTTP/1.1 201 Created
Content-Type: application/xml
<<other headers>>

<order id="233">
   <link rel="self" href=""/>
   <date>December 22, 2008 06:56</date>


  • dataType specifies the format of response to expect. Its related to Accept header. JQuery will try to infer it based on the Content-Type of the response.


Sample request:

GET /someFolder/index.html HTTP/1.1
Accept: application/xml
<<other headers>>


Above request is expecting XML from the server.

Regarding your question,

contentType: "application/json; charset=utf-8",
dataType: "json",

Here you are sending json data using UTF8 character set, and you expect back json data from the server. As per the JQuery docs for dataType,

The json type parses the fetched data file as a JavaScript object and returns the constructed object as the result data.

So what you get in success handler is proper javascript object(JQuery converts the json object for you)


contentType: "application/json",
dataType: "text",

Here you are sending json data, since you haven't mentioned the encoding, as per the JQuery docs,

If no charset is specified, data will be transmitted to the server using the server's default charset; you must decode this appropriately on the server side.

and since dataType is specified as text, what you get in success handler is plain text, as per the docs for dataType,

The text and xml types return the data with no processing. The data is simply passed on to the success handler

What's the difference between an argument and a parameter?

The parameters of a function/method describe to you the values that it uses to calculate its result.

The arguments of a function are the values assigned to these parameters during a particular call of the function/method.

Outputting data from unit test in Python

Expanding @F.C. 's answer, this works quite well for me:

class MyTest(unittest.TestCase):
    def messenger(self, message):
            self.assertEqual(1, 2, msg=message)
        except AssertionError as e:      
            print "\nMESSENGER OUTPUT: %s" % str(e),

Enums in Javascript with ES6

You can check Enumify, a very good and well featured library for ES6 enums.

Getting parts of a URL (Regex)

This improved version should work as reliably as a parser.

   // Applies to URI, not just URL or URN:
   // (?:([^:/?#]+):)?(?://([^/?#]*))?([^?#]*)(?:\?([^#]*))?(?:#(.*))?
   // $@ matches the entire uri
   // $1 matches scheme (ftp, http, mailto, mshelp, ymsgr, etc)
   // $2 matches authority (host, user:pwd@host, etc)
   // $3 matches path
   // $4 matches query (http GET REST api, etc)
   // $5 matches fragment (html anchor, etc)
   // Match specific schemes, non-optional authority, disallow white-space so can delimit in text, and allow 'www.' w/o scheme
   // Note the schemes must match ^[^\s|:/?#]+(?:\|[^\s|:/?#]+)*$
   // (?:()(www\.[^\s/?#]+\.[^\s/?#]+)|(schemes)://([^\s/?#]*))([^\s?#]*)(?:\?([^\s#]*))?(#(\S*))?
   // Validate the authority with an orthogonal RegExp, so the RegExp above won’t fail to match any valid urls.
   function uriRegExp( flags, schemes/* = null*/, noSubMatches/* = false*/ )
      if( !schemes )
         schemes = '[^\\s:\/?#]+'
      else if( !RegExp( /^[^\s|:\/?#]+(?:\|[^\s|:\/?#]+)*$/ ).test( schemes ) )
         throw TypeError( 'expected URI schemes' )
      return noSubMatches ? new RegExp( '(?:www\\.[^\\s/?#]+\\.[^\\s/?#]+|' + schemes + '://[^\\s/?#]*)[^\\s?#]*(?:\\?[^\\s#]*)?(?:#\\S*)?', flags ) :
         new RegExp( '(?:()(www\\.[^\\s/?#]+\\.[^\\s/?#]+)|(' + schemes + ')://([^\\s/?#]*))([^\\s?#]*)(?:\\?([^\\s#]*))?(?:#(\\S*))?', flags )

   function uriSchemesRegExp()
      return 'about|callto|ftp|gtalk|http|https|irc|ircs|javascript|mailto|mshelp|sftp|ssh|steam|tel|view-source|ymsgr'

Force GUI update from UI Thread

you can try this

using System.Windows.Forms; // u need this to include.

MethodInvoker updateIt = delegate
                    this.label1.Text = "Started...";

See if it works.

aspx page to redirect to a new page

Redirect aspx :


    <script runat="server">
    private void Page_Load(object sender, System.EventArgs e)
    Response.Status = "301 Moved Permanently";


How to find array / dictionary value using key?

It looks like you're writing PHP, in which case you want:

$arr=array('us'=>'United', 'ca'=>'canada');
echo $arr[$key];

Notice that the ('us'=>'United', 'ca'=>'canada') needs to be a parameter to the array function in PHP.

Most programming languages that support associative arrays or dictionaries use arr['key'] to retrieve the item specified by 'key'

For instance:


ruby-1.9.1-p378 > h = {'us' => 'USA', 'ca' => 'Canada' }
 => {"us"=>"USA", "ca"=>"Canada"} 
ruby-1.9.1-p378 > h['ca']
 => "Canada" 


>>> h = {'us':'USA', 'ca':'Canada'}
>>> h['ca']


class P
    static void Main()
        var d = new System.Collections.Generic.Dictionary<string, string> { {"us", "USA"}, {"ca", "Canada"}};


t = {us='USA', ca='Canada'}
print( -- Lua's a little different with tables

Change New Google Recaptcha (v2) Width

I have this function in the document ready event so that the reCaptcha is dynamically sized. Anyone should be able to drop this in place and go.

function ScaleReCaptcha()
if (document.getElementsByClassName('g-recaptcha').length > 0)
{parentWidth = document.getElementsByClassName('g-recaptcha') [0].parentNode.clientWidth;
         childWidth = document.getElementsByClassName('g-recaptcha')[0].firstChild.clientWidth;
         scale = (parentWidth) / (childWidth);
         new_width = childWidth * scale;
         document.getElementsByClassName('g-recaptcha')[0].style.transform = 'scale(' + scale + ')';
         document.getElementsByClassName('g-recaptcha')[0].style.transformOrigin = '0 0';

How to know if a Fragment is Visible?

Try this if you have only one Fragment

if (getSupportFragmentManager().getBackStackEntryCount() == 0) {
                    //TODO: Your Code Here

Facebook Open Graph not clearing cache

Years later and this is still a common problem, but its not always facebook's cache: It is very often human error (allow me to elaborate)

OG:TYPE effects your image scrape:

  1. not the same as

Be aware that og:type=website will cause any /sub-pages/ of that url to become "canonical". This means you will have trouble getting your images to update using the scraper no matter what you do.

Consider this "assumption and common mistake"

-<meta property="og:type" content="website" /> => (parent)
-<meta property="og:type" content="website" /> =>
-<meta property="og:type" content="website" /> =>
- Ergo: /sub-page/ and /child-2/ will inherit the og:image of the parent

Those are not "all websites", 1 is a website, the others are articles.

If you do that Facebook will think all of those are canonical and it will put the FIRST og:image into all of them. (try it, you'll see) - if you set the og:url to be your root or parent domain you've told facebook they are all canonical. (there is good reason for that, but its off topic)

Consider this solution (which is what most people "really want")

-<meta property="og:type" content="article" /> =>
-<meta property="og:type" content="article" /> =>

If you do that now Facebook will give you far far less problems with scraping your NEW images.

In closing, YES the cache busters, random vars, changing urls and suggestions here can work, but they will seem like "intermittent voodoo" if the og:type is not specified correctly.

PS: remember that a CDN or serverside cache will serve to Facebook's scraper even if you "think" you can see the most recent version. (I wont spend any time on this other than to point out it will waste colossal amounts of your time if not double checked.)

Kotlin Android start new Activity

From activity to activity

val intent = Intent(this,

From fragment to activity

val intent = Intent(activity,

Is it really impossible to make a div fit its size to its content?

CSS display setting

It is of course possible - JSFiddle proof of concept where you can see all three possible solutions:

  • display: inline-block - this is the one you're not aware of

  • position: absolute

  • float: left/right

C# : "A first chance exception of type 'System.InvalidOperationException'"

Consider using System.Windows.Forms.Timer instead of System.Threading.Timer for a GUI application, for timers that are based on the Windows message queue instead of on dedicated threads or the thread pool.

In your scenario, for the purpose of periodic updates of UI, it seems particularly appropriate since you don't really have a background work or long calculation to perform. You just want to do periodic small tasks that have to happen on the UI thread anyway.

Can I set subject/content of email using mailto:?

Note that it is not possible to use HTML in the message body, according to RFC 2368:

The special hname "body" indicates that the associated hvalue is the body of the message. The "body" hname should contain the content for the first text/plain body part of the message. The mailto URL is primarily intended for generation of short text messages that are actually the content of automatic processing (such as "subscribe" messages for mailing lists), not general MIME bodies.


jQuery .search() to any string

Ah, that would be because RegExp is not jQuery. :)

Try this page. jQuery.attr doesn't return a String so that would certainly cause in this regard. Fortunately I believe you can just use .text() to return the String representation.

Something like:


JavaScript Promises - reject vs. throw

There's one difference — which shouldn't matter — that the other answers haven't touched on, so:

There's no difference that's likely to matter, no. Yes, there is a very small difference.

If the fulfillment handler passed to then throws, the promise returned by that call to then is rejected with what was thrown.

If it returns a rejected promise, the promise returned by the call to then is resolved to that promise (and will ultimately be rejected, since the promise it's resolved to is rejected), which may introduce one extra async "tick" (one more loop in the microtask queue, to put it in browser terms).

Any code that relies on that difference is fundamentally broken, though. :-) It shouldn't be that sensitive to the timing of the promise settlement.

Here's an example:

function usingThrow(val) {
    return Promise.resolve(val)
        .then(v => {
            if (v !== 42) {
                throw new Error(`${v} is not 42!`);
            return v;
function usingReject(val) {
    return Promise.resolve(val)
        .then(v => {
            if (v !== 42) {
                return Promise.reject(new Error(`${v} is not 42!`));
            return v;

// The rejection handler on this chain may be called **after** the
// rejection handler on the following chain
.then(v => console.log(v))
.catch(e => console.error("Error from usingReject:", e.message));

// The rejection handler on this chain may be called **before** the
// rejection handler on the preceding chain
.then(v => console.log(v))
.catch(e => console.error("Error from usingThrow:", e.message));

If you run that, as of this writing you get:

Error from usingThrow: 2 is not 42!
Error from usingReject: 1 is not 42!

Note the order.

Compare that to the same chains but both using usingThrow:

function usingThrow(val) {
    return Promise.resolve(val)
        .then(v => {
            if (v !== 42) {
                throw new Error(`${v} is not 42!`);
            return v;

.then(v => console.log(v))
.catch(e => console.error("Error from usingThrow:", e.message));

.then(v => console.log(v))
.catch(e => console.error("Error from usingThrow:", e.message));

which shows that the rejection handlers ran in the other order:

Error from usingThrow: 1 is not 42!
Error from usingThrow: 2 is not 42!

I said "may" above because there's been some work in other areas that removed this unnecessary extra tick in other similar situations if all of the promises involved are native promises (not just thenables). (Specifically: In an async function, return await x originally introduced an extra async tick vs. return x while being otherwise identical; ES2020 changed it so that if x is a native promise, the extra tick is removed.)

Again, any code that's that sensitive to the timing of the settlement of a promise is already broken. So really it doesn't/shouldn't matter.

In practical terms, as other answers have mentioned:

  • As Kevin B pointed out, throw won't work if you're in a callback to some other function you've used within your fulfillment handler — this is the biggie
  • As lukyer pointed out, throw abruptly terminates the function, which can be useful (but you're using return in your example, which does the same thing)
  • As Vencator pointed out, you can't use throw in a conditional expression (? :), at least not for now

Other than that, it's mostly a matter of style/preference, so as with most of those, agree with your team what you'll do (or that you don't care either way), and be consistent.

How to Right-align flex item?

As easy as

.main {
    display: flex;

Fitting empirical distribution to theoretical ones with Scipy (Python)?

fit() method mentioned by @Saullo Castro provides maximum likelihood estimates (MLE). The best distribution for your data is the one give you the highest can be determined by several different ways: such as

1, the one that gives you the highest log likelihood.

2, the one that gives you the smallest AIC, BIC or BICc values (see wiki:, basically can be viewed as log likelihood adjusted for number of parameters, as distribution with more parameters are expected to fit better)

3, the one that maximize the Bayesian posterior probability. (see wiki:

Of course, if you already have a distribution that should describe you data (based on the theories in your particular field) and want to stick to that, you will skip the step of identifying the best fit distribution.

scipy does not come with a function to calculate log likelihood (although MLE method is provided), but hard code one is easy: see Is the build-in probability density functions of `scipy.stat.distributions` slower than a user provided one?

find index of an int in a list

FindIndex seems to be what you're looking for:



list1.FindIndex(x => x==5);


// given list1 {3, 4, 6, 5, 7, 8}
list1.FindIndex(x => x==5);  // should return 3, as list1[3] == 5;

"getaddrinfo failed", what does that mean?

It most likely means the hostname can't be resolved.

import socket
socket.getaddrinfo('localhost', 8080)

If it doesn't work there, it's not going to work in the Bottle example. You can try '' instead of 'localhost' in case that's the problem.

Numeric for loop in Django templates

You should use "slice" in template, a example like this:


contexts = {
    'ALL_STORES': Store.objects.all(),

return render_to_response('store_list.html', contexts, RequestContext(request, processors=[custom_processor]))

in store_list.html:

{% for store in ALL_STORES|slice:":10" %}
    <li class="store_item">{{ }}</li>
{% endfor %}

ImportError: No module named PytQt5

this can be solved under MacOS X by installing pyqt with brew

brew install pyqt

Right way to split an std::string into a vector<string>

std::vector<std::string> split(std::string text, char delim) {
    std::string line;
    std::vector<std::string> vec;
    std::stringstream ss(text);
    while(std::getline(ss, line, delim)) {
    return vec;

split("String will be split", ' ') -> {"String", "will", "be", "split"}

split("Hello, how are you?", ',') -> {"Hello", "how are you?"}

EDIT: Here's a thing I made, this can use multi-char delimiters, albeit I'm not 100% sure if it always works:

std::vector<std::string> split(std::string text, std::string delim) {
    std::vector<std::string> vec;
    size_t pos = 0, prevPos = 0;
    while (1) {
        pos = text.find(delim, prevPos);
        if (pos == std::string::npos) {
            return vec;

        vec.push_back(text.substr(prevPos, pos - prevPos));
        prevPos = pos + delim.length();

Error in eval(expr, envir, enclos) : object not found

I think I got what I was looking for..

data.train <- read.table("Assign2.WineComplete.csv",sep=",",header=T)
fit <- rpart(quality ~ ., method="class",data=data.train)
text(fit, use.n=TRUE)

Adding a SVN repository in Eclipse

At my day job I sit behind a corporate firewall protecting and caching web traffic (among other things). For the most part it stays out of the way. But sometimes it rears its ugly head and stands firmly in the path of what I am trying to do.

Earlier this week I was trying to look at a cool new general validation system for ColdFusion called Validat, put out by the great guys at Alagad. They don't have a download on the RIAForge site yet, but the files are available via SVN. I loaded up the subclipse plugin into my Eclipse, restarted and began adding the Validat SVN repository. I started getting errors abou the "RA layer request failed" and "svn: PROPFIND request failed on /Validat/trunk", followed by an error about not being able to connect to the SVN server.

I already had Eclipse setup with my proxy settings, so I thought I was doing something wrong or Alagad didn't actually have the subversion repository up-and-available. After going home that night, I tried it from home and wa-la it worked. Stupid proxy server! So the subclipse plugin won't use the Eclipse proxy settings. (Can that be fixed please!). After digging around the subclipse help site and being redirected to the help, then unproductively searching through the eclipse workspace, plugins, and configuration folders for the settings file, I was finally able to figure out how to set up subclipse to use the proxy server.

In my Windows development environment, I opened the following file: C:\Documents and Settings\MyUserId\Application Data\Subversion\servers in my favorite text editor. Near the bottom of that file is a [global] section with http-proxy-host and http-proxy-port settings. I uncommented those two lines, modified them for my corporate proxy server, went back to the SVN Repository view in Eclipse, refreshed the Validat repository and Boom! it worked!


Webview load html from assets directory

You are getting the WebView before setting the Content view so the wv is probably null.

public class ViewWeb extends Activity {  
        public void onCreate(Bundle savedInstanceState) {  
            WebView wv;  
            wv = (WebView) findViewById(;  
            wv.loadUrl("file:///android_asset/aboutcertified.html");   // now it will not fail here

jquery find closest previous sibling with class

You can follow this code:

<script src=""></script>
    $(document).ready(function () {
        $(".add").on("click", function () {
            var v = $(this).closest(".division").find("input[name='roll']").val();

for ($i = 1; $i <= 5; $i++) {
    echo'<div class = "division">'
        . '<form method="POST" action="">'
        . '<p><input type="number" name="roll" placeholder="Enter Roll"></p>'
        . '<p><input type="button" class="add" name = "submit" value = "Click"></p>'
        . '</form></div>';

You can get idea from this.

JavaScript Regular Expression Email Validation

var emailRegex = /^[A-Z0-9_'%=+!`#~$*?^{}&|-]+([\.][A-Z0-9_'%=+!`#~$*?^{}&|-]+)*@[A-Z0-9-]+(\.[A-Z0-9-]+)+$/i;

How to export library to Jar in Android Studio?

Here's yet another, slightly different answer with a few enhancements.

This code takes the .jar right out of the .aar. Personally, that gives me a bit more confidence that the bits being shipped via .jar are the same as the ones shipped via .aar. This also means that if you're using ProGuard, the output jar will be obfuscated as desired.

I also added a super "makeJar" task, that makes jars for all build variants.

task(makeJar) << {
    // Empty. We'll add dependencies for this task below

// Generate jar creation tasks for all build variants
android.libraryVariants.all { variant ->
    String taskName = "makeJar${}"

    // Create a jar by extracting it from the assembled .aar
    // This ensures that products distributed via .aar and .jar exactly the same bits
    task (taskName, type: Copy) {
        String archiveName = "${}-${}"
        String outputDir = "${buildDir.getPath()}/outputs"

        dependsOn "assemble${}"
        rename ('classes.jar', "${archiveName}-${variant.mergedFlavor.versionName}.jar")

    makeJar.dependsOn tasks[taskName]

For the curious reader, I struggled to determine the correct variables and parameters that the plugin uses to name .aar files. I finally found them in the Android Open Source Project here.

Setting default checkbox value in Objective-C?

Documentation on UISwitch says:

[mySwitch setOn:NO]; 

In Interface Builder, select your switch and in the Attributes inspector you'll find State which can be set to on or off.

Android Color Picker

try this open source projects that might help you

How to change font size in a textbox in html

Here are some ways to edit the text and the size of the box:



<textarea rows="5" cols="30" style="font-size: 12pt" id="myText">Enter 
Text Here</textarea>

Java NIO FileChannel versus FileOutputstream performance / usefulness

My experience with larger files sizes has been that java.nio is faster than Solidly faster. Like in the >250% range. That said, I am eliminating obvious bottlenecks, which I suggest your micro-benchmark might suffer from. Potential areas for investigating:

The buffer size. The algorithm you basically have is

  • copy from disk to buffer
  • copy from buffer to disk

My own experience has been that this buffer size is ripe for tuning. I've settled on 4KB for one part of my application, 256KB for another. I suspect your code is suffering with such a large buffer. Run some benchmarks with buffers of 1KB, 2KB, 4KB, 8KB, 16KB, 32KB and 64KB to prove it to yourself.

Don't perform java benchmarks that read and write to the same disk.

If you do, then you are really benchmarking the disk, and not Java. I would also suggest that if your CPU is not busy, then you are probably experiencing some other bottleneck.

Don't use a buffer if you don't need to.

Why copy to memory if your target is another disk or a NIC? With larger files, the latency incured is non-trivial.

Like other have said, use FileChannel.transferTo() or FileChannel.transferFrom(). The key advantage here is that the JVM uses the OS's access to DMA (Direct Memory Access), if present. (This is implementation dependent, but modern Sun and IBM versions on general purpose CPUs are good to go.) What happens is the data goes straight to/from disc, to the bus, and then to the destination... bypassing any circuit through RAM or the CPU.

The web app I spent my days and night working on is very IO heavy. I've done micro benchmarks and real-world benchmarks too. And the results are up on my blog, have a look-see:

Use production data and environments

Micro-benchmarks are prone to distortion. If you can, make the effort to gather data from exactly what you plan to do, with the load you expect, on the hardware you expect.

My benchmarks are solid and reliable because they took place on a production system, a beefy system, a system under load, gathered in logs. Not my notebook's 7200 RPM 2.5" SATA drive while I watched intensely as the JVM work my hard disc.

What are you running on? It matters.

Java IOException "Too many open files"

You're obviously not closing your file descriptors before opening new ones. Are you on windows or linux?

How do I set the request timeout for one controller action in an mvc application

<location path="ControllerName/ActionName">
        <httpRuntime executionTimeout="1000"/>

Probably it is better to set such values in web.config instead of controller. Hardcoding of configurable options is considered harmful.

How do I zip two arrays in JavaScript?

Zip Arrays of same length:


const zip = (a, b) =>, i) => [k, b[i]]);

console.log(zip([1,2,3], ["a","b","c"]));
// [[1, "a"], [2, "b"], [3, "c"]]

Zip Arrays of different length:

Using Array.from()

const zip = (a, b) => Array.from(Array(Math.max(b.length, a.length)), (_, i) => [a[i], b[i]]);

console.log( zip([1,2,3], ["a","b","c","d"]) );
// [[1, "a"], [2, "b"], [3, "c"], [undefined, "d"]]

Using Array.prototype.fill() and

const zip = (a, b) => Array(Math.max(b.length, a.length)).fill().map((_,i) => [a[i], b[i]]);

console.log(zip([1,2,3], ["a","b","c","d"]));
// [[1, "a"], [2, "b"], [3, "c"], [undefined, 'd']]

BehaviorSubject vs Observable?

Think of Observables as a pipe with flowing water in it, sometimes water flows and sometimes it doesn't. In some cases, you may actually need a pipe that has always water in it, you can do this by creating a special pipe which always contains a water no matter how small it is, lets call this special pipe BehaviorSubject, if you happens to be a water supply provider in your community, you can sleep peacefully at night knowing that your newly installed pipe just works.

In technical terms: you may encounter usescases where an Observable should always have value in it, perhaps you want to capture the value of a input text over time, you can then create an instance of BehaviorSubject to ensure this kind of behavior, lets say:

const firstNameChanges = new BehaviorSubject("<empty>");

// pass value changes."Jon");"Arya");

You can then use "value" to sample changes over time.


This comes handy when you combine Observables later, by taking a look at the type of your stream as BehaviorSubject you can then ensure that the stream at least fires or signal just once atleast.

MySQL: #126 - Incorrect key file for table

I got this error when I set ft_min_word_len = 2 in my.cnf, which lowers the minimum word length in a full text index to 2, from the default of 4.

Repairing the table fixed the problem.

ModuleNotFoundError: What does it mean __main__ is not a package?

If you have created directory and sub-directory, follow the steps below and please keep in mind all directory must have to get it recognized as a directory.

  1. In your script, include import sys and sys.path, you will be able to see all the paths available to Python. You must be able to see your current working directory.

  2. Now import sub-directory and respective module that you want to use using: import subdir.subdir.modulename as abc and now you can use the methods in that module.

enter image description here

As an example, you can see in this screenshot I have one parent directory and two sub-directories and under second sub-directories I have the module CommonFunction. On the right my console shows that after execution of sys.path, I can see my working directory.

How do I get the current date in Cocoa

You have problems with iOS 4.2? Use this Code:

NSDate *currDate = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:@"dd.MM.YY HH:mm:ss"];
NSString *dateString = [dateFormatter stringFromDate:currDate];

-->20.01.2011 10:36:02

How to convert a unix timestamp (seconds since epoch) to Ruby DateTime?

One command to convert date time to Unix format and then to string

    DateTime.strptime(,'%s').strftime("%d %m %y") #Converts time from Unix format
    DateTime.strptime(,'%s') #Converts date and time from unix format to DateTime

finally strftime is used to format date


    irb(main):034:0> DateTime.strptime("1410321600",'%s').strftime("%d %m %y")
    "10 09 14"

Inserting an item in a Tuple

one way is to convert it to list

>>> b=list(mytuple)
>>> b.append("something")
>>> a=tuple(b)

What is a "callback" in C and how are they implemented?

A callback function in C is the equivalent of a function parameter / variable assigned to be used within another function.Wiki Example

In the code below,

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

/* The calling function takes a single callback as a parameter. */
void PrintTwoNumbers(int (*numberSource)(void)) {
    printf("%d and %d\n", numberSource(), numberSource());

/* A possible callback */
int overNineThousand(void) {
    return (rand() % 1000) + 9001;

/* Another possible callback. */
int meaningOfLife(void) {
    return 42;

/* Here we call PrintTwoNumbers() with three different callbacks. */
int main(void) {
    return 0;

The function (*numberSource) inside the function call PrintTwoNumbers is a function to "call back" / execute from inside PrintTwoNumbers as dictated by the code as it runs.

So if you had something like a pthread function you could assign another function to run inside the loop from its instantiation.

How to find prime numbers between 0 - 100?

First, change your inner code for another loop (for and while) so you can repeat the same code for different values.

More specific for your problem, if you want to know if a given n is prime, you need to divide it for all values between 2 and sqrt(n). If any of the modules is 0, it is not prime.

If you want to find all primes, you can speed it and check n only by dividing by the previously found primes. Another way of speeding the process is the fact that, apart from 2 and 3, all the primes are 6*k plus or less 1.

JavaScript Editor Plugin for Eclipse

Complete the following steps in Eclipse to get plugins for JavaScript files:

  1. Open Eclipse -> Go to "Help" -> "Install New Software"
  2. Select the repository for your version of Eclipse. I have Juno so I selected
  3. Expand "Programming Languages" -> Check the box next to "JavaScript Development Tools"
  4. Click "Next" -> "Next" -> Accept the Terms of the License Agreement -> "Finish"
  5. Wait for the software to install, then restart Eclipse (by clicking "Yes" button at pop up window)
  6. Once Eclipse has restarted, open "Window" -> "Preferences" -> Expand "General" and "Editors" -> Click "File Associations" -> Add ".js" to the "File types:" list, if it is not already there
  7. In the same "File Associations" dialog, click "Add" in the "Associated editors:" section
  8. Select "Internal editors" radio at the top
  9. Select "JavaScript Viewer". Click "OK" -> "OK"

To add JavaScript Perspective: (Optional)
10. Go to "Window" -> "Open Perspective" -> "Other..."
11. Select "JavaScript". Click "OK"

To open .html or .js file with highlighted JavaScript syntax:
12. (Optional) Select JavaScript Perspective
13. Browse and Select .html or .js file in Script Explorer in [JavaScript Perspective] (Or Package Explorer [Java Perspective] Or PyDev Package Explorer [PyDev Perspective] Don't matter.)
14. Right-click on .html or .js file -> "Open With" -> "Other..."
15. Select "Internal editors"
16. Select "Java Script Editor". Click "OK" (see JavaScript syntax is now highlighted )

How can I use Guzzle to send a POST request in JSON?

The simple and basic way (guzzle6):

$client = new Client([
    'headers' => [ 'Content-Type' => 'application/json' ]

$response = $client->post('',
    ['body' => json_encode(
            'hello' => 'World'

To get the response status code and the content of the body I did this:

echo '<pre>' . var_export($response->getStatusCode(), true) . '</pre>';
echo '<pre>' . var_export($response->getBody()->getContents(), true) . '</pre>';

jQuery keypress() event not firing?

With jQuery, I've done it this way:

function checkKey(e){
     switch (e.keyCode) {
        case 40:
        case 38:
        case 37:
        case 39:

if ($.browser.mozilla) {
    $(document).keypress (checkKey);
} else {
    $(document).keydown (checkKey);

Also, try these plugins, which looks like they do all that work for you:

JsonMappingException: No suitable constructor found for type [simple type, class ]: can not instantiate from JSON object

Thumb Rule: Add a default constructor for each class you used as a mapping class. You missed this and issue arise!
Simply add default constructor and it should work.

List<String> to ArrayList<String> conversion issue

In Kotlin List can be converted into ArrayList through passing it as a constructor parameter.


PyCharm shows unresolved references error for valid code

I finally got this working after none of the proposed solutions worked for me. I was playing with a django rest framework project and was using a virtualenv I had setup with it. I was able to get Pycharm fixed by marking the root folder as the sources root, but then django's server would throw resolve exceptions. So one would work when the other wouldn't and vice versa.

Ultimately I just had to mark the subfolder as the sources root in pycharm. So my structure was like this


That second playground folder is the one I had to mark as the sources root for everything to work as expected. That didn't present any issues for my scenario so it was a workable solution.

Just thought I'd share in case someone else can use it.

Biggest differences of Thrift vs Protocol Buffers?

Protocol Buffers seems to have a more compact representation, but that's only an impression I get from reading the Thrift whitepaper. In their own words:

We decided against some extreme storage optimizations (i.e. packing small integers into ASCII or using a 7-bit continuation format) for the sake of simplicity and clarity in the code. These alterations can easily be made if and when we encounter a performance-critical use case that demands them.

Also, it may just be my impression, but Protocol Buffers seems to have some thicker abstractions around struct versioning. Thrift does have some versioning support, but it takes a bit of effort to make it happen.

How to sort a file, based on its numerical values for a field?

Take a peek at the man page for sort...

   -n, --numeric-sort
          compare according to string numerical value

So here is an example...

sort -n filename

Install Visual Studio 2013 on Windows 7

your log files shows it is stopping on error "0x8004C000"

From MS Website (

Setup Status

Restart not required
0x80044000 [-2147205120]

Restart required
0x8004C000 [-2147172352]

If the only block to be reported is “Reboot Pending,” the returned value is the Incomplete-Reboot Required value (0x80048bc7).

How to do logging in React Native?

Every developer facing this issue of debugging with the react native, even I faced too and I refer this and solution is sufficient for me at initial level, it cover few ways that help us to try and use what ever comfortable with us

  1. Debugging with console.log
  2. Debugging code (logic) with Nuclide
  3. Debugging code(logic) with Chrome
  4. Use Xcode to debug GUI

Find position of a node using xpath

I do a lot of Novell Identity Manager stuff, and XPATH in that context looks a little different.

Assume the value you are looking for is in a string variable, called TARGET, then the XPATH would be:


Additionally it was pointed out that to save a few characters of space, the following would work as well:

count(attr/value[.='$TARGET']/preceding::*) + 1

I also posted a prettier version of this at Novell's Cool Solutions: Using XPATH to get the position node

How can I build XML in C#?

For simple cases, I would also suggest looking at XmlOutput a fluent interface for building Xml.

XmlOutput is great for simple Xml creation with readable and maintainable code, while generating valid Xml. The orginal post has some great examples.

Get bytes from std::string in C++

std::string::data would seem to be sufficient and most efficient. If you want to have non-const memory to manipulate (strange for encryption) you can copy the data to a buffer using memcpy:

unsigned char buffer[mystring.length()];
memcpy(buffer,, mystring.length());

STL fanboys would encourage you to use std::copy instead:

std::copy(mystring.begin(), mystring.end(), buffer);

but there really isn't much of an upside to this. If you need null termination use std::string::c_str() and the various string duplication techniques others have provided, but I'd generally avoid that and just query for the length. Particularly with cryptography you just know somebody is going to try to break it by shoving nulls in to it, and using std::string::data() discourages you from lazily making assumptions about the underlying bits in the string.

How do I correctly detect orientation change using Phonegap on iOS?

I've found this code to detect if the device is in landscape orientation and in this case add a splash page saying "change orientation to see the site". It's working on iOS, android and windows phones. I think that this is very useful since it's quite elegant and avoid to set a landscape view for the mobile site. The code is working very well. The only thing not completely satisfying is that if someone load the page being in landscape view the splash page doesn't appears.

(function() {
    'use strict';

    var isMobile = {
        Android: function() {
            return navigator.userAgent.match(/Android/i);
        BlackBerry: function() {
            return navigator.userAgent.match(/BlackBerry/i);
        iOS: function() {
            return navigator.userAgent.match(/iPhone|iPad|iPod/i);
        Opera: function() {
            return navigator.userAgent.match(/Opera Mini/i);
        Windows: function() {
            return navigator.userAgent.match(/IEMobile/i);
        any: function() {
            return (isMobile.Android() || isMobile.BlackBerry() || isMobile.iOS() || isMobile.Opera() || isMobile.Windows());
    if (isMobile.any()) {
        window.addEventListener('resize', doOnOrientationChange, 'false');

    function doOnOrientationChange() {
        var a = document.getElementById('alert');
        var b = document.body;
        var w = b.offsetWidth;
        var h = b.offsetHeight;
        (w / h > 1) ? (a.className = 'show', b.className = 'full-body') : (a.className = 'hide', b.className = '');

And the HTML: <div id="alert" class="hide"> <div id="content">This site is not thought to be viewed in landscape mode, please turn your device </div> </div>

Test if number is odd or even

Try this,

$number = 10;
 switch ($number%2)
 case 0:
 echo "It's even";
 echo "It's odd";

Homebrew refusing to link OpenSSL

If migrating your mac breaks homebrew:

I migrated my mac, and it unlinked all my homebrew installs - including OpenSSL. This broke gem install, which is how I first noticed the problem and started trying to repair this.

After a million solutions (when migrating to OSX Sierra - 10.12.5), the solution ended up being comically simple:

brew reinstall ruby
brew reinstall openssl

How to import existing Git repository into another?

If you want to retain the exact commit history of the second repository and therefore also retain the ability to easily merge upstream changes in the future then here is the method you want. It results in unmodified history of the subtree being imported into your repo plus one merge commit to move the merged repository to the subdirectory.

git remote add XXX_remote <path-or-url-to-XXX-repo>
git fetch XXX_remote
git merge -s ours --no-commit --allow-unrelated-histories XXX_remote/master
git read-tree --prefix=ZZZ/ -u XXX_remote/master
git commit -m "Imported XXX as a subtree."

You can track upstream changes like so:

git pull -s subtree XXX_remote master

Git figures out on its own where the roots are before doing the merge, so you don't need to specify the prefix on subsequent merges.

The downside is that in the merged history the files are unprefixed (not in a subdirectory). As a result git log ZZZ/a will show you all the changes (if any) except those in the merged history. You can do:

git log --follow -- a

but that won't show the changes other then in the merged history.

In other words, if you don't change ZZZ's files in repository XXX, then you need to specify --follow and an unprefixed path. If you change them in both repositories, then you have 2 commands, none of which shows all the changes.

Git versions before 2.9: You don’t need to pass the --allow-unrelated-histories option to git merge.

The method in the other answer that uses read-tree and skips the merge -s ours step is effectively no different than copying the files with cp and committing the result.

Original source was from github's "Subtree Merge" help article. And another useful link.

How to filter in NaN (pandas)?

This doesn't work because NaN isn't equal to anything, including NaN. Use pd.isnull(df.var2) instead.

Select a date from date picker using Selenium webdriver

I tried this code, it may work for you also:

            DateFormat dateFormat2 = new SimpleDateFormat("dd"); 
            Date date2 = new Date();

            String today = dateFormat2.format(date2); 

            //find the calendar
            WebElement dateWidget = driver.findElement("dp-calendar"));  
            List<WebElement> columns=dateWidget.findElements(By.tagName("td"));  

            //comparing the text of cell with today's date and clicking it.
            for (WebElement cell : columns)
               if (cell.getText().equals(today))

What is the Java equivalent for LINQ?

There is a project called quaere.

It's a Java framework which adds the ability to query collections.

Note: According to the author, the project is not maintained anymore.

Read/Parse text file line by line in VBA

You Can use this code to read line by line in text file and You could also check about the first character is "*" then you can leave that..

Public Sub Test()

    Dim ReadData as String

    Open "C:\satheesh\myfile\file.txt" For Input As #1

    Do Until EOF(1) 
       Line Input #1, ReadData 'Adding Line to read the whole line, not only first 128 positions
    If Not Left(ReadData, 1) = "*" then
       '' you can write the variable ReadData into the database or file
    End If 


    Close #1

End Sub

How do I get my Maven Integration tests to run

By default, Maven only runs tests that have Test somewhere in the class name.

Rename to IntegrationTest and it'll probably work.

Alternatively you can change the Maven config to include that file but it's probably easier and better just to name your tests SomethingTest.

From Inclusions and Exclusions of Tests:

By default, the Surefire Plugin will automatically include all test classes with the following wildcard patterns:

  • \*\*/Test\*.java - includes all of its subdirectory and all java filenames that start with "Test".
  • \*\*/\* - includes all of its subdirectory and all java filenames that end with "Test".
  • \*\*/\* - includes all of its subdirectory and all java filenames that end with "TestCase".

If the test classes does not go with the naming convention, then configure Surefire Plugin and specify the tests you want to include.

"for loop" with two variables?

If you really just have lock-step iteration over a range, you can do it one of several ways:

for i in range(x):
  j = i
# or
for i, j in enumerate(range(x)):
# or
for i, j in ((i,i) for i in range(x)):

All of the above are equivalent to for i, j in zip(range(x), range(y)) if x <= y.

If you want a nested loop and you only have two iterables, just use a nested loop:

for i in range(x):
  for i in range(y):

If you have more than two iterables, use itertools.product.

Finally, if you want lock-step iteration up to x and then to continue to y, you have to decide what the rest of the x values should be.

for i, j in itertools.zip_longest(range(x), range(y), fillvalue=float('nan')):
# or
for i in range(min(x,y)):
  j = i
for i in range(min(x,y), max(x,y)):
  j = float('nan')

MySQL Job failed to start

I had the same problem. But i discover that my hd is full.

$ sudo cat /var/log/upstart/mysql.log
/proc/self/fd/9: ERROR: The partition with /var/lib/mysql is too full!

So, I run

$ df -h

And I got the message

/dev/xvda1      7.8G  7.4G     0 100% /

Then I found out which folder was full by running the following command on the terminal

$ cd /var/www
$ for i in *; do echo $i; find $i |wc -l; done

This give me the number of files on each folder on /var/www. I logged into the folder with most files, and deleted some backup files, and i continued deleting useless files and cache files.

then I run $ sudo /etc/init.d/mysql start and it work again

Jquery get form field value

An alternative approach, without searching for the field html:

var $form = $('#' + DynamicValueAssignedHere).find('form');
var formData = $form.serializeArray();
var myFieldName = 'FirstName';
var myFieldFilter = function (field) {
  return == myFieldName;
var value = formData.filter(myFieldFilter)[0].value;

Why dict.get(key) instead of dict[key]?

The purpose is that you can give a default value if the key is not found, which is very useful


How to edit a JavaScript alert box title?

I had a similar issue when I wanted to change the box title and button title of the default confirm box. I have gone for the Jquery Ui dialog plugin

When I had the following:

function testConfirm() {
  if (confirm("Are you sure you want to delete?")) {
    //some stuff

I have changed it to:

function testConfirm() {

  var $dialog = $('<div></div>')
    .html("Are you sure you want to delete?")
      resizable: false,
      title: "Confirm Deletion",
      modal: true,
      buttons: {
        Cancel: function() {
        "Delete": function() {
          //some stuff


Can be seen working here

Hope that helps.

How to disable a ts rule for a specific line?


TS 3.9 introduces a new magic comment. @ts-expect-error will:

  • have same functionality as @ts-ignore
  • trigger an error, if actually no compiler error has been suppressed (= indicates useless flag)
if (false) {
  // @ts-expect-error: Let's ignore a single compiler error like this unreachable code 
  console.log("hello"); // compiles

// If @ts-expect-error didn't suppress anything at all, we now get a nice warning 
let flag = true;
// ...
if (flag) {
  // @ts-expect-error
  // ^~~~~~~~~~~~~~~^ error: "Unused '@ts-expect-error' directive.(2578)"


@ts-ignore and @ts-expect-error can be used for all sorts of compiler errors. For type issues (like in OP), I recommend one of the following alternatives due to narrower error suppression scope:

? Use any type

// type assertion for single expression
delete ($ as any).summernote.options.keyMap.pc.TAB;

// new variable assignment for multiple usages
const $$: any = $
delete $$.summernote.options.keyMap.pc.TAB;
delete $$.summernote.options.keyMap.mac.TAB;

? Augment JQueryStatic interface

// ./global.d.ts
interface JQueryStatic {
  summernote: any;

// ./main.ts
delete $.summernote.options.keyMap.pc.TAB; // works

In other cases, shorthand module declarations or module augmentations for modules with no/extendable types are handy utilities. A viable strategy is also to keep not migrated code in .js and use --allowJs with checkJs: false.

import sun.misc.BASE64Encoder results in error compiled in Eclipse

Java 6 ships the javax.xml.bind.DatatypeConverter. This class provides two static methods that support the same decoding & encoding:

parseBase64Binary() / printBase64Binary()

Update: Since Java 8 we now have a much better Base64 Support.

Use this and you will not need an extra library, like Apache Commons Codec.

How to correctly save instance state of Fragments in back stack?

I just want to give the solution that I came up with that handles all cases presented in this post that I derived from Vasek and devconsole. This solution also handles the special case when the phone is rotated more than once while fragments aren't visible.

Here is were I store the bundle for later use since onCreate and onSaveInstanceState are the only calls that are made when the fragment isn't visible

MyObject myObject;
private Bundle savedState = null;
private boolean createdStateInDestroyView;
private static final String SAVED_BUNDLE_TAG = "saved_bundle";

public void onCreate(Bundle savedInstanceState) {
    if (savedInstanceState != null) {
        savedState = savedInstanceState.getBundle(SAVED_BUNDLE_TAG);

Since destroyView isn't called in the special rotation situation we can be certain that if it creates the state we should use it.

public void onDestroyView() {
    savedState = saveState();
    createdStateInDestroyView = true;
    myObject = null;

This part would be the same.

private Bundle saveState() { 
    Bundle state = new Bundle();
    state.putSerializable(SAVED_BUNDLE_TAG, myObject);
    return state;

Now here is the tricky part. In my onActivityCreated method I instantiate the "myObject" variable but the rotation happens onActivity and onCreateView don't get called. Therefor, myObject will be null in this situation when the orientation rotates more than once. I get around this by reusing the same bundle that was saved in onCreate as the out going bundle.

public void onSaveInstanceState(Bundle outState) {

    if (myObject == null) {
        outState.putBundle(SAVED_BUNDLE_TAG, savedState);
    } else {
        outState.putBundle(SAVED_BUNDLE_TAG, createdStateInDestroyView ? savedState : saveState());
    createdStateInDestroyView = false;

Now wherever you want to restore the state just use the savedState bundle

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    if(savedState != null) {
        myObject = (MyObject) savedState.getSerializable(SAVED_BUNDLE_TAG);

How do you run CMD.exe under the Local System Account?

Found an answer here which seems to solve the problem by adding /k start to the binPath parameter. So that would give you:

sc create testsvc binpath= "cmd /K start" type= own type= interact

However, Ben said that didn't work for him and when I tried it on Windows Server 2008 it did create the cmd.exe process under local system, but it wasn't interactive (I couldn't see the window).

I don't think there is an easy way to do what you ask, but I'm wondering why you're doing it at all? Are you just trying to see what is happening when you run your service? Seems like you could just use logging to determine what is happening instead of having to run the exe as local system...

Image resolution for mdpi, hdpi, xhdpi and xxhdpi

Please read the Android Documentation regarding screen sizes.

From a base image size, there is a 3:4:6:8:12:16 scaling ratio in drawable size by DPI.

LDPI - 0.75x
MDPI - Original size // means 1.0x here 
HDPI - 1.5x
XHDPI - 2.0x
XXXHDPI - 4.0x

For example, 100x100px image on a MDPI will be the same size of a 200x200px on a XHDPI screen.

How to get the index of an element in an IEnumerable?

An alternative to finding the index after the fact is to wrap the Enumerable, somewhat similar to using the Linq GroupBy() method.

public static class IndexedEnumerable
    public static IndexedEnumerable<T> ToIndexed<T>(this IEnumerable<T> items)
        return IndexedEnumerable<T>.Create(items);

public class IndexedEnumerable<T> : IEnumerable<IndexedEnumerable<T>.IndexedItem>
    private readonly IEnumerable<IndexedItem> _items;

    public IndexedEnumerable(IEnumerable<IndexedItem> items)
        _items = items;

    public class IndexedItem
        public IndexedItem(int index, T value)
            Index = index;
            Value = value;

        public T Value { get; private set; }
        public int Index { get; private set; }

    public static IndexedEnumerable<T> Create(IEnumerable<T> items)
        return new IndexedEnumerable<T>(items.Select((item, index) => new IndexedItem(index, item)));

    public IEnumerator<IndexedItem> GetEnumerator()
        return _items.GetEnumerator();

    IEnumerator IEnumerable.GetEnumerator()
        return GetEnumerator();

Which gives a use case of:

var items = new[] {1, 2, 3};
var indexedItems = items.ToIndexed();
foreach (var item in indexedItems)
    Console.WriteLine("items[{0}] = {1}", item.Index, item.Value);

IIS w3svc error

Go to Task Manager --> Processes and manually stop the W3SVC process. After doing this the process should start normally when restarting IIS

Jenkins restrict view of jobs per user

Only one plugin help me: Role-Based Strategy :

But official documentation ( is deficient.

The following configurations worked for me:


Basically you just need to create roles and match them with job names using regex.

Calendar.getInstance(TimeZone.getTimeZone("UTC")) is not returning UTC time

You are definitely missing a small thing and that is you are not setting a default value:


So the code would look like:

Calendar cal_Two = Calendar.getInstance(TimeZone.getTimeZone("UTC"));

Explanation: If you want to change the time zone, set the default time zone using TimeZone.setDefault()

Creating columns in listView and add items

Your first problem is that you are passing -3 to the 2nd parameter of Columns.Add. It needs to be -2 for it to auto-size the column. Source: (look at the comments on the code example at the bottom)

private void initListView()
    // Add columns
    lvRegAnimals.Columns.Add("Id", -2,HorizontalAlignment.Left);
    lvRegAnimals.Columns.Add("Name", -2, HorizontalAlignment.Left);
    lvRegAnimals.Columns.Add("Age", -2, HorizontalAlignment.Left);

You can also use the other overload, Add(string). E.g:


Reference for more overloads:

Second, to add items to the ListView, you need to create instances of ListViewItem and add them to the listView's Items collection. You will need to use the string[] constructor.

var item1 = new ListViewItem(new[] {"id123", "Tom", "24"});
var item2 = new ListViewItem(new[] {person.Id, person.Name, person.Age});

You can also store objects in the item's Tag property.

item2.Tag = person;

And then you can extract it

var person = item2.Tag as Person;

Let me know if you have any questions and I hope this helps!

Searching in a ArrayList with custom objects for certain strings

try this

ArrayList<Datapoint > searchList = new ArrayList<Datapoint >();
String search = "a";
int searchListLength = searchList.size();
for (int i = 0; i < searchListLength; i++) {
if (searchList.get(i).getName().contains(search)) {
//Do whatever you want here

How to size an Android view based on its parent's dimensions

It's something like this:

<RelativeLayout xmlns:android=""

    android:weightSum="100">   <!-- Overall weights sum of children elements -->

        android:layout_width="0dp"   <!-- It's 0dp because is determined by android:layout_weight -->
        android:id="@+id/spinner" />



        android:id="@+id/input" />



iPhone hide Navigation Bar only on first page

The simplest implementation may be to just have each view controller specify whether its navigation bar is hidden or not in its viewWillAppear:animated: method. The same approach works well for hiding/showing the toolbar as well:

- (void)viewWillAppear:(BOOL)animated {
    [self.navigationController setToolbarHidden:YES/NO animated:animated];
    [super viewWillAppear:animated];

Cannot find Dumpbin.exe

As for VS2017, I found it under C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.14.26428\bin\Hostx64\x64

How to update large table with millions of rows in SQL Server?

I want share my experience. A few days ago I have to update 21 million records in table with 76 million records. My colleague suggested the next variant. For example, we have the next table 'Persons':

Id | FirstName | LastName | Email            | JobTitle
1  | John      |  Doe     | [email protected]     | Software Developer
2  | John1     |  Doe1    | [email protected]     | Software Developer
3  | John2     |  Doe2    | [email protected]     | Web Designer

Task: Update persons to the new Job Title: 'Software Developer' -> 'Web Developer'.

1. Create Temporary Table 'Persons_SoftwareDeveloper_To_WebDeveloper (Id INT Primary Key)'

2. Select into temporary table persons which you want to update with the new Job Title:

INSERT INTO Persons_SoftwareDeveloper_To_WebDeveloper SELECT Id FROM
Persons WITH(NOLOCK) --avoid lock 
WHERE JobTitle = 'Software Developer' 
OPTION(MAXDOP 1) -- use only one core

Depends on rows count, this statement will take some time to fill your temporary table, but it would avoid locks. In my situation it took about 5 minutes (21 million rows).

3. The main idea is to generate micro sql statements to update database. So, let's print them:

DECLARE @i INT, @pagesize INT, @totalPersons INT
    SET @i=0
    SET @pagesize=2000
    SELECT @totalPersons = MAX(Id) FROM Persons

    while @i<= @totalPersons
    Print '
    UPDATE persons 
      SET persons.JobTitle = ''ASP.NET Developer''
      FROM  Persons_SoftwareDeveloper_To_WebDeveloper tmp
      JOIN Persons persons ON tmp.Id = persons.Id
      where persons.Id between '+cast(@i as varchar(20)) +' and '+cast(@i+@pagesize as varchar(20)) +' 
        PRINT ''Page ' + cast((@i / @pageSize) as varchar(20))  + ' of ' + cast(@totalPersons/@pageSize as varchar(20))+'
     set @i=@i+@pagesize

After executing this script you will receive hundreds of batches which you can execute in one tab of MS SQL Management Studio.

4. Run printed sql statements and check for locks on table. You always can stop process and play with @pageSize to speed up or speed down updating(don't forget to change @i after you pause script).

5. Drop Persons_SoftwareDeveloper_To_AspNetDeveloper. Remove temporary table.

Minor Note: This migration could take a time and new rows with invalid data could be inserted during migration. So, firstly fix places where your rows adds. In my situation I fixed UI, 'Software Developer' -> 'Web Developer'.

Set a cookie to never expire

My privilege prevents me making my comment on the first post so it will have to go here.

Consideration should be taken into account of 2038 unix bug when setting 20 years in advance from the current date which is suggest as the correct answer above.

Your cookie on January 19, 2018 + (20 years) could well hit 2038 problem depending on the browser and or versions you end up running on.

Get JSONArray without array name?

I've assumed a named JSONArray is a JSONObject and accessed the data from the server to populate an Android GridView. For what it is worth my method is:

private String[] fillTable( JSONObject jsonObject ) {
   String[] dummyData = new String[] {"1", "2", "3", "4", "5", "6", "7","1", "2", "3", "4", "5", "6", "7","1", "2", "3", "4", "5", "6", "7", };
  if( jsonObject != null ) {
      ArrayList<String> data = new ArrayList<String>();
      try {
          // jsonArray looks like { "everything" : [{}, {},] }
          JSONArray jsonArray = jsonObject.getJSONArray( "everything" );
          int number = jsonArray.length(); //How many rows have got from the database?
          Log.i( Constants.INFORMATION, "Number of ows returned:  " + Integer.toString( number ) );
                  // Array elements look like this
          //{"success":1,"error":0,"name":"English One","owner":"Tutor","description":"Initial Alert","posted":"2013-08-09 15:35:40"}
          for( int element = 0; element < number; element++ ) { //visit each element
             JSONObject jsonObject_local = jsonArray.getJSONObject( element );
             //  Overkill on the error/success checking
             Log.e("JSON SUCCESS", Integer.toString( jsonObject_local.getInt(Constants.KEY_SUCCESS) ) );
             Log.e("JSON ERROR", Integer.toString( jsonObject_local.getInt(Constants.KEY_ERROR) ) );
                if ( jsonObject_local.getInt( Constants.KEY_SUCCESS) == Constants.JSON_SUCCESS ) {
                   String name = jsonObject_local.getString( Constants.KEY_NAME );
                   data.add( name );
                   String owner = jsonObject_local.getString( Constants.KEY_OWNER );
                   data.add( owner );
                   String description = jsonObject_local.getString( Constants.KEY_DESCRIPTION );
                   Log.i( "DESCRIPTION", description );
                   data.add( description ); 
                   String date = jsonObject_local.getString( Constants.KEY_DATE );
                   data.add( date );
                else {
                    for( int i = 0; i < 4; i++ ) {
                        data.add( "ERROR" );
  }  //JSON object is null
  catch ( JSONException jsone) {
      Log.e( "JSON EXCEPTION", jsone.getMessage() );
      dummyData = data.toArray( dummyData );
  return dummyData;


Adding Only Untracked Files

git ls-files -o --exclude-standard gives untracked files, so you can do something like below ( or add an alias to it):

git add $(git ls-files -o --exclude-standard)

Send file via cURL from form POST in PHP

For people finding this post and using PHP5.5+, this might help.

I was finding the approach suggested by netcoder wasn't working. i.e. this didn't work:

$tmpfile = $_FILES['image']['tmp_name'];
$filename = basename($_FILES['image']['name']);
$data = array(
    'uploaded_file' => '@'.$tmpfile.';filename='.$filename,
$ch = curl_init();   
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

I would receive in the $_POST var the 'uploaded_file' field - and nothing in the $_FILES var.

It turns out that for php5.5+ there is a new curl_file_create() function you need to use. So the above would become:

$data = array(
    'uploaded_file' => curl_file_create($tmpfile, $_FILES['image']['type'], $filename)

As the @ format is now deprecated.

How to test if a DataSet is empty?

It is not a valid answer as it gives following error

Cannot find table 0.

Use the following statement instead

if (ds.Tables.Count == 0)
     //DataSet is empty

JQuery get data from JSON array

You're not looping over the items. Try this instead:

$.getJSON(url, function(data){
    $.each(, function (index, value) {

Comparison of DES, Triple DES, AES, blowfish encryption for data

                DES                               AES
Developed       1977                              2000
Key Length      56 bits                           128, 192, or 256 bits
Cipher Type     Symmetric                         Symmetric
Block Size      64 bits                           128 bits
Security        inadequate                        secure
Performance     Fast                              Slow

How do I select last 5 rows in a table without sorting?

This is just about the most bizarre query I've ever written, but I'm pretty sure it gets the "last 5" rows from a table without ordering:

select * 
from issues
where issueid not in (
    select top (
        (select count(*) from issues) - 5
    ) issueid
    from issues

Note that this makes use of SQL Server 2005's ability to pass a value into the "top" clause - it doesn't work on SQL Server 2000.

Disable dragging an image from an HTML page

img {
  -moz-user-select: none;
  -webkit-user-select: none;
  -ms-user-select: none;
  user-select: none;
  -webkit-user-drag: none;
  user-drag: none;
  -webkit-touch-callout: none;

I used it on my website at It's works like a magic!!! :)

Exit codes in Python

From the documentation for sys.exit:

The optional argument arg can be an integer giving the exit status (defaulting to zero), or another type of object. If it is an integer, zero is considered “successful termination” and any nonzero value is considered “abnormal termination” by shells and the like. Most systems require it to be in the range 0-127, and produce undefined results otherwise. Some systems have a convention for assigning specific meanings to specific exit codes, but these are generally underdeveloped; Unix programs generally use 2 for command line syntax errors and 1 for all other kind of errors.

One example where exit codes are used are in shell scripts. In Bash you can check the special variable $? for the last exit status:

me@mini:~$ python -c ""; echo $?
me@mini:~$ python -c "import sys; sys.exit(0)"; echo $?
me@mini:~$ python -c "import sys; sys.exit(43)"; echo $?

Personally I try to use the exit codes I find in /usr/include/asm-generic/errno.h (on a Linux system), but I don't know if this is the right thing to do.

How to create an empty DataFrame with a specified schema?

Lets assume you want a data frame with the following schema:

 |-- k: string (nullable = true)
 |-- v: integer (nullable = false)

You simply define schema for a data frame and use empty RDD[Row]:

import org.apache.spark.sql.types.{
    StructType, StructField, StringType, IntegerType}
import org.apache.spark.sql.Row

val schema = StructType(
    StructField("k", StringType, true) ::
    StructField("v", IntegerType, false) :: Nil)

// Spark < 2.0
// sqlContext.createDataFrame(sc.emptyRDD[Row], schema) 
spark.createDataFrame(sc.emptyRDD[Row], schema)

PySpark equivalent is almost identical:

from pyspark.sql.types import StructType, StructField, IntegerType, StringType

schema = StructType([
    StructField("k", StringType(), True), StructField("v", IntegerType(), False)

# or df = sc.parallelize([]).toDF(schema)

# Spark < 2.0 
# sqlContext.createDataFrame([], schema)
df = spark.createDataFrame([], schema)

Using implicit encoders (Scala only) with Product types like Tuple:

import spark.implicits._

Seq.empty[(String, Int)].toDF("k", "v")

or case class:

case class KV(k: String, v: Int)




Why is JsonRequestBehavior needed?

To make it easier for yourself you could also create an actionfilterattribute

public class AllowJsonGetAttribute : ActionFilterAttribute
    public override void OnResultExecuting(ResultExecutingContext filterContext)
        var jsonResult = filterContext.Result as JsonResult;

        if (jsonResult == null)
            throw new ArgumentException("Action does not return a JsonResult, 
                                                   attribute AllowJsonGet is not allowed");

        jsonResult.JsonRequestBehavior = JsonRequestBehavior.AllowGet;            


and use it on your action

public JsonResult MyAjaxAction()
    return Json("this is my test");

'Access denied for user 'root'@'localhost' (using password: NO)'

You can reset your root password. Have in mind that it is not advisable to use root without password.

Convert NSDate to NSString

In Swift:

var formatter = NSDateFormatter()
formatter.dateFormat = "yyyy"
var dateString = formatter.stringFromDate(YourNSDateInstanceHERE)

Build fat static library (device + simulator) using Xcode and SDK 4+

I have spent many hours trying to build a fat static library that will work on armv7, armv7s, and the simulator. Finally found a solution.

The gist is to build the two libraries (one for the device and then one for the simulator) separately, rename them to distinguish from each other, and then lipo -create them into one library.

lipo -create libPhone.a libSimulator.a -output libUniversal.a

I tried it and it works!

Passing arguments to angularjs filters

From what I understand you can't pass an arguments to a filter function (when using the 'filter' filter). What you would have to do is to write a custom filter, sth like this:

.filter('weDontLike', function(){

return function(items, name){

    var arrayToReturn = [];        
    for (var i=0; i<items.length; i++){
        if (items[i].name != name) {

    return arrayToReturn;

Here is the working jsFiddle:

The other simple alternative, without writing custom filters is to store a name to filter out in a scope and then write:

$scope.weDontLike = function(item) {
  return != $;

How to prevent robots from automatically filling up a form?

With increasingly sophisticated spam bots and techniques like automated browsers, it will become harder to determine the source of spam. But whether posted by software, a human, or both, spam is spam because of its content. I think the best solution is to run the posted content through an anti-spam API like Cleantalk or Akismet. It's relatively cheap and effective and doesn't hassle the user. You can check form submission times and the other traditional checks for less sophisticated bots before hitting the API.

Executing a shell script from a PHP script

It's a simple problem. When you are running from terminal, you are running the php file from terminal as a privileged user. When you go to the php from your web browser, the php script is being run as the web server user which does not have permissions to execute files in your home directory. In Ubuntu, the www-data user is the apache web server user. If you're on ubuntu you would have to do the following: chown yourusername:www-data /home/testuser/testscript chmod g+x /home/testuser/testscript

what the above does is transfers user ownership of the file to you, and gives the webserver group ownership of it. the next command gives the group executable permission to the file. Now the next time you go ahead and do it from the browser, it should work.

Append an empty row in dataframe using pandas

You can add it by appending a Series to the dataframe as follows. I am assuming by blank you mean you want to add a row containing only "Nan". You can first create a Series object with Nan. Make sure you specify the columns while defining 'Series' object in the -Index parameter. The you can append it to the DF. Hope it helps!

from numpy import nan as Nan
import pandas as pd

>>> df1 = pd.DataFrame({'A': ['A0', 'A1', 'A2', 'A3'],
...                     'B': ['B0', 'B1', 'B2', 'B3'],
...                     'C': ['C0', 'C1', 'C2', 'C3'],
...                     'D': ['D0', 'D1', 'D2', 'D3']},
...                     index=[0, 1, 2, 3])

>>> s2 = pd.Series([Nan,Nan,Nan,Nan], index=['A', 'B', 'C', 'D'])
>>> result = df1.append(s2)
>>> result
     A    B    C    D
0   A0   B0   C0   D0
1   A1   B1   C1   D1
2   A2   B2   C2   D2
3   A3   B3   C3   D3
4  NaN  NaN  NaN  NaN

How can I time a code segment for testing performance with Pythons timeit?

I see the question has already been answered, but still want to add my 2 cents for the same.

I have also faced similar scenario in which I have to test the execution times for several approaches and hence written a small script, which calls timeit on all functions written in it.

The script is also available as github gist here.

Hope it will help you and others.

from random import random
import types

def list_without_comprehension():
    l = []
    for i in xrange(1000):
        l.append(int(random()*100 % 100))
    return l

def list_with_comprehension():
    # 1K random numbers between 0 to 100
    l = [int(random()*100 % 100) for _ in xrange(1000)]
    return l

# operations on list_without_comprehension
def sort_list_without_comprehension():

def reverse_sort_list_without_comprehension():

def sorted_list_without_comprehension():

# operations on list_with_comprehension
def sort_list_with_comprehension():

def reverse_sort_list_with_comprehension():

def sorted_list_with_comprehension():

def main():
    objs = globals()
    funcs = []
    f = open("", "w+")

    for objname in objs:
        if objname != 'main' and type(objs[objname]) == types.FunctionType:
    for func in funcs:
        f.write('''echo "Timing: %(funcname)s"
python -m timeit "import timeit_demo; timeit_demo.%(funcname)s();"\n\n
echo "------------------------------------------------------------"
''' % dict(
                funcname = func,


if __name__ == "__main__":

    from os import system

    #Works only for *nix platforms

    #un-comment below for windows

Oracle "Partition By" Keyword

It is the SQL extension called analytics. The "over" in the select statement tells oracle that the function is a analytical function, not a group by function. The advantage to using analytics is that you can collect sums, counts, and a lot more with just one pass through of the data instead of looping through the data with sub selects or worse, PL/SQL.

It does look confusing at first but this will be second nature quickly. No one explains it better then Tom Kyte. So the link above is great.

Of course, reading the documentation is a must.

python: order a list of numbers without built-in sort, min, max function

How do I keep looping through until the len(new_list) = len(data_list)

while len(new_list) != len(data_list):
    # ...

Maybe like this?

And no, it’s not necessary to create a new list; most sorting algorithms work by changing the list in place.

What you probably trying to do is Selection sort with a separate list. See the Wikipedia article for more information about that sorting algorithm and you’ll see how it works with a single list, and how efficient it is (spoiler: it isn’t).

How to Convert date into MM/DD/YY format in C#

Look into using the ToString() method with a specified format.

taking input of a string word by word

Put the line in a stringstream and extract word by word back:

#include <iostream>
#include <sstream>
using namespace std;

int main()
    string t;

    istringstream iss(t);
    string word;
    while(iss >> word) {
        /* do stuff with word */

Of course, you can just skip the getline part and read word by word from cin directly.

And here you can read why is using namespace std considered bad practice.

How do you read scanf until EOF in C?

Man, if you are using Windows, EOF is not reached by pressing enter, but by pressing Crtl+Z at the console. This will print "^Z", an indicator of EOF. The behavior of functions when reading this (the EOF or Crtl+Z):

Function: Output: scanf(...) EOF gets(<variable>) NULL feof(stdin) 1 getchar() EOF

Creating an iframe with given HTML dynamically

Allthough your src = encodeURI should work, I would have gone a different way:

var iframe = document.createElement('iframe');
var html = '<body>Foo</body>';

As this has no x-domain restraints and is completely done via the iframe handle, you may access and manipulate the contents of the frame later on. All you need to make sure of is, that the contents have been rendered, which will (depending on browser type) start during/after the .write command is issued - but not nescessarily done when close() is called.

A 100% compatible way of doing a callback could be this approach:

<html><body onload="parent.myCallbackFunc(this.window)"></body></html>

Iframes has the onload event, however. Here is an approach to access the inner html as DOM (js):

iframe.onload = function() {
   var div=iframe.contentWindow.document.getElementById('mydiv');

dotnet ef not found in .NET Core 3

For everyone using .NET Core CLI on MinGW MSYS. After installing using

dotnet tool install --global dotnet-ef

add this line to to bashrc file c:\msys64\home\username\ .bashrc (location depend on your setup)

export PATH=$PATH:/c/Users/username/.dotnet/tools

FirstOrDefault returns NullReferenceException if no match is found

Use the SingleOrDefault() instead of FirstOrDefault().

Setting onSubmit in React.js

<form onSubmit={(e) => {this.doSomething(); e.preventDefault();}}></form>

it work fine for me

How do I base64 encode a string efficiently using Excel VBA?

This code works very fast. It comes from here

Option Explicit

Private Const clOneMask = 16515072          '000000 111111 111111 111111
Private Const clTwoMask = 258048            '111111 000000 111111 111111
Private Const clThreeMask = 4032            '111111 111111 000000 111111
Private Const clFourMask = 63               '111111 111111 111111 000000

Private Const clHighMask = 16711680         '11111111 00000000 00000000
Private Const clMidMask = 65280             '00000000 11111111 00000000
Private Const clLowMask = 255               '00000000 00000000 11111111

Private Const cl2Exp18 = 262144             '2 to the 18th power
Private Const cl2Exp12 = 4096               '2 to the 12th
Private Const cl2Exp6 = 64                  '2 to the 6th
Private Const cl2Exp8 = 256                 '2 to the 8th
Private Const cl2Exp16 = 65536              '2 to the 16th

Public Function Encode64(sString As String) As String

    Dim bTrans(63) As Byte, lPowers8(255) As Long, lPowers16(255) As Long, bOut() As Byte, bIn() As Byte
    Dim lChar As Long, lTrip As Long, iPad As Integer, lLen As Long, lTemp As Long, lPos As Long, lOutSize As Long

    For lTemp = 0 To 63                                 'Fill the translation table.
        Select Case lTemp
            Case 0 To 25
                bTrans(lTemp) = 65 + lTemp              'A - Z
            Case 26 To 51
                bTrans(lTemp) = 71 + lTemp              'a - z
            Case 52 To 61
                bTrans(lTemp) = lTemp - 4               '1 - 0
            Case 62
                bTrans(lTemp) = 43                      'Chr(43) = "+"
            Case 63
                bTrans(lTemp) = 47                      'Chr(47) = "/"
        End Select
    Next lTemp

    For lTemp = 0 To 255                                'Fill the 2^8 and 2^16 lookup tables.
        lPowers8(lTemp) = lTemp * cl2Exp8
        lPowers16(lTemp) = lTemp * cl2Exp16
    Next lTemp

    iPad = Len(sString) Mod 3                           'See if the length is divisible by 3
    If iPad Then                                        'If not, figure out the end pad and resize the input.
        iPad = 3 - iPad
        sString = sString & String(iPad, Chr(0))
    End If

    bIn = StrConv(sString, vbFromUnicode)               'Load the input string.
    lLen = ((UBound(bIn) + 1) \ 3) * 4                  'Length of resulting string.
    lTemp = lLen \ 72                                   'Added space for vbCrLfs.
    lOutSize = ((lTemp * 2) + lLen) - 1                 'Calculate the size of the output buffer.
    ReDim bOut(lOutSize)                                'Make the output buffer.

    lLen = 0                                            'Reusing this one, so reset it.

    For lChar = LBound(bIn) To UBound(bIn) Step 3
        lTrip = lPowers16(bIn(lChar)) + lPowers8(bIn(lChar + 1)) + bIn(lChar + 2)    'Combine the 3 bytes
        lTemp = lTrip And clOneMask                     'Mask for the first 6 bits
        bOut(lPos) = bTrans(lTemp \ cl2Exp18)           'Shift it down to the low 6 bits and get the value
        lTemp = lTrip And clTwoMask                     'Mask for the second set.
        bOut(lPos + 1) = bTrans(lTemp \ cl2Exp12)       'Shift it down and translate.
        lTemp = lTrip And clThreeMask                   'Mask for the third set.
        bOut(lPos + 2) = bTrans(lTemp \ cl2Exp6)        'Shift it down and translate.
        bOut(lPos + 3) = bTrans(lTrip And clFourMask)   'Mask for the low set.
        If lLen = 68 Then                               'Ready for a newline
            bOut(lPos + 4) = 13                         'Chr(13) = vbCr
            bOut(lPos + 5) = 10                         'Chr(10) = vbLf
            lLen = 0                                    'Reset the counter
            lPos = lPos + 6
            lLen = lLen + 4
            lPos = lPos + 4
        End If
    Next lChar

    If bOut(lOutSize) = 10 Then lOutSize = lOutSize - 2 'Shift the padding chars down if it ends with CrLf.

    If iPad = 1 Then                                    'Add the padding chars if any.
        bOut(lOutSize) = 61                             'Chr(61) = "="
    ElseIf iPad = 2 Then
        bOut(lOutSize) = 61
        bOut(lOutSize - 1) = 61
    End If

    Encode64 = StrConv(bOut, vbUnicode)                 'Convert back to a string and return it.

End Function

Public Function Decode64(sString As String) As String

    Dim bOut() As Byte, bIn() As Byte, bTrans(255) As Byte, lPowers6(63) As Long, lPowers12(63) As Long
    Dim lPowers18(63) As Long, lQuad As Long, iPad As Integer, lChar As Long, lPos As Long, sOut As String
    Dim lTemp As Long

    sString = Replace(sString, vbCr, vbNullString)      'Get rid of the vbCrLfs.  These could be in...
    sString = Replace(sString, vbLf, vbNullString)      'either order.

    lTemp = Len(sString) Mod 4                          'Test for valid input.
    If lTemp Then
        Call Err.Raise(vbObjectError, "MyDecode", "Input string is not valid Base64.")
    End If

    If InStrRev(sString, "==") Then                     'InStrRev is faster when you know it's at the end.
        iPad = 2                                        'Note:  These translate to 0, so you can leave them...
    ElseIf InStrRev(sString, "=") Then                  'in the string and just resize the output.
        iPad = 1
    End If

    For lTemp = 0 To 255                                'Fill the translation table.
        Select Case lTemp
            Case 65 To 90
                bTrans(lTemp) = lTemp - 65              'A - Z
            Case 97 To 122
                bTrans(lTemp) = lTemp - 71              'a - z
            Case 48 To 57
                bTrans(lTemp) = lTemp + 4               '1 - 0
            Case 43
                bTrans(lTemp) = 62                      'Chr(43) = "+"
            Case 47
                bTrans(lTemp) = 63                      'Chr(47) = "/"
        End Select
    Next lTemp

    For lTemp = 0 To 63                                 'Fill the 2^6, 2^12, and 2^18 lookup tables.
        lPowers6(lTemp) = lTemp * cl2Exp6
        lPowers12(lTemp) = lTemp * cl2Exp12
        lPowers18(lTemp) = lTemp * cl2Exp18
    Next lTemp

    bIn = StrConv(sString, vbFromUnicode)               'Load the input byte array.
    ReDim bOut((((UBound(bIn) + 1) \ 4) * 3) - 1)       'Prepare the output buffer.

    For lChar = 0 To UBound(bIn) Step 4
        lQuad = lPowers18(bTrans(bIn(lChar))) + lPowers12(bTrans(bIn(lChar + 1))) + _
                lPowers6(bTrans(bIn(lChar + 2))) + bTrans(bIn(lChar + 3))           'Rebuild the bits.
        lTemp = lQuad And clHighMask                    'Mask for the first byte
        bOut(lPos) = lTemp \ cl2Exp16                   'Shift it down
        lTemp = lQuad And clMidMask                     'Mask for the second byte
        bOut(lPos + 1) = lTemp \ cl2Exp8                'Shift it down
        bOut(lPos + 2) = lQuad And clLowMask            'Mask for the third byte
        lPos = lPos + 3
    Next lChar

    sOut = StrConv(bOut, vbUnicode)                     'Convert back to a string.
    If iPad Then sOut = Left$(sOut, Len(sOut) - iPad)   'Chop off any extra bytes.
    Decode64 = sOut

End Function

How to count number of files in each directory?

Assuming you have GNU find, let it find the directories and let bash do the rest:

find . -type d -print0 | while read -d '' -r dir; do
    printf "%5d files in directory %s\n" "${#files[@]}" "$dir"

Set Culture in an ASP.Net MVC app

I would do it in the Initialize event of the controller like this...

    protected override void Initialize(System.Web.Routing.RequestContext requestContext)

        const string culture = "en-US";
        CultureInfo ci = CultureInfo.GetCultureInfo(culture);

        Thread.CurrentThread.CurrentCulture = ci;
        Thread.CurrentThread.CurrentUICulture = ci;

When to use 'raise NotImplementedError'?

You might want to you use the @property decorator,

>>> class Foo():
...     @property
...     def todo(self):
...             raise NotImplementedError("To be implemented")
>>> f = Foo()
>>> f.todo
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 4, in todo
NotImplementedError: To be implemented

How do I specify new lines on Python, when writing on files?

The same way with '\n', though you'd probably not need the '\r'. Is there a reason you have it in your Java version? If you do need/want it, you can use it in the same way in Python too.

What's the best way to cancel event propagation between nested ng-click calls?

<div ng-click="methodName(event)"></div>

IN controller use

$scope.methodName = function(event) { 

Git asks for username every time I push

Make sure that you are using SSH instead of http. Check this SO answer.

Transparent background in JPEG image

You can't make a JPEG image transparent. You should use a format that allows transparency, like GIF or PNG.

Paint will open these files, but AFAIK it'll erase transparency if you edit the file. Use some other application like Paint.NET (it's free).

Edit: since other people have mentioned it: you can convert JPEG images into PNG, in any editor that's capable of working with both types.

Load properties file in JAR?

The problem is that you are using getSystemResourceAsStream. Use simply getResourceAsStream. System resources load from the system classloader, which is almost certainly not the class loader that your jar is loaded into when run as a webapp.

It works in Eclipse because when launching an application, the system classloader is configured with your jar as part of its classpath. (E.g. java -jar my.jar will load my.jar in the system class loader.) This is not the case with web applications - application servers use complex class loading to isolate webapplications from each other and from the internals of the application server. For example, see the tomcat classloader how-to, and the diagram of the classloader hierarchy used.

EDIT: Normally, you would call getClass().getResourceAsStream() to retrieve a resource in the classpath, but as you are fetching the resource in a static initializer, you will need to explicitly name a class that is in the classloader you want to load from. The simplest approach is to use the class containing the static initializer, e.g.

[public] class MyClass {

Bash script and /bin/bash^M: bad interpreter: No such file or directory

Your file has Windows line endings, which is confusing Linux.

Remove the spurious CR characters. You can do it with the following command:

 $ sed -i -e 's/\r$//'

How to display a confirmation dialog when clicking an <a> link?

You can also try this:

<a href="" onclick="if (confirm('Delete selected item?')){return true;}else{event.stopPropagation(); event.preventDefault();};" title="Link Title">
    Link Text

Username and password in command for git push

For anyone having issues with passwords with special chars just omit the password and it will prompt you for it:

git push https://[email protected]/YOUR_GIT_USERNAME/yourGitFileName.git

git replace local version with remote version

This is the safest solution:

git stash

Now you can do whatever you want without fear of conflicts.

For instance:

git checkout origin/master

If you want to include the remote changes in the master branch you can do:

git reset --hard origin/master

This will make you branch "master" to point to "origin/master".

Have border wrap around text

Try this and see if you get what you are aiming for:

<div id='page' style='width: 600px'>_x000D_
  <h1 style='border:2px black solid; font-size:42px; width:fit-content; width:-webkit-fit-content; width:-moz-fit-content;'>Title</h1>_x000D_

Generate Java class from JSON?

If you're using Jackson (the most popular library there), try

Its open source (last updated on Jun 7, 2013 as of year 2020) and anyone should be able to contribute.


A JsonToJava source class file generator that deduces the schema based on supplied sample json data and generates the necessary java data structures.

It encourages teams to think in Json first, before writing actual code.


  • Can generate classes for an arbitrarily complex hierarchy (recursively)
  • Can read your existing Java classes and if it can deserialize into those structures, will do so
  • Will prompt for user input when ambiguous cases exist

sql: check if entry in table A exists in table B

                   FROM   A 
                   WHERE  A.ID = B.ID)

What is cURL in PHP?

cURL is a way you can hit a URL from your code to get a html response from it. cURL means client URL which allows you to connect with other URLs and use their responses in your code.

Reliable way for a Bash script to get the full path to itself

Easy to read? Below is an alternative. It ignores symlinks

  cd $(dirname "$0")

echo -n "current "
echo script $currentDir

Since I posted the above answer a couple years ago, I've evolved my practice to using this linux specific paradigm, which properly handles symlinks:

ORIGIN=$(dirname $(readlink -f $0))

Execute a terminal command from a Cocoa app

kent's article gave me a new idea. this runCommand method doesn't need a script file, just runs a command by a line:

- (NSString *)runCommand:(NSString *)commandToRun
    NSTask *task = [[NSTask alloc] init];
    [task setLaunchPath:@"/bin/sh"];

    NSArray *arguments = [NSArray arrayWithObjects:
                          @"-c" ,
                          [NSString stringWithFormat:@"%@", commandToRun],
    NSLog(@"run command:%@", commandToRun);
    [task setArguments:arguments];

    NSPipe *pipe = [NSPipe pipe];
    [task setStandardOutput:pipe];

    NSFileHandle *file = [pipe fileHandleForReading];

    [task launch];

    NSData *data = [file readDataToEndOfFile];

    NSString *output = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    return output;

You can use this method like this:

NSString *output = runCommand(@"ps -A | grep mysql");

How do I loop through children objects in javascript?

In the year 2020 / 2021 it is even easier with Array.from to 'convert' from a array-like nodes to an actual array, and then using .map to loop through the resulting array. The code is as simple as the follows:


Hiding a button in Javascript

You can set its visibility property to hidden.

Here is a little demonstration, where one button is used to toggle the other one:

<input type="button" id="toggler" value="Toggler" onClick="action();" />
<input type="button" id="togglee" value="Togglee" />

    var hidden = false;
    function action() {
        hidden = !hidden;
        if(hidden) {
            document.getElementById('togglee').style.visibility = 'hidden';
        } else {
            document.getElementById('togglee').style.visibility = 'visible';

Remove HTML tags from string including &nbsp in C#

I took @Ravi Thapliyal's code and made a method: It is simple and might not clean everything, but so far it is doing what I need it to do.

public static string ScrubHtml(string value) {
    var step1 = Regex.Replace(value, @"<[^>]+>|&nbsp;", "").Trim();
    var step2 = Regex.Replace(step1, @"\s{2,}", " ");
    return step2;

Finding duplicate integers in an array and display how many times they occurred

int[] array = { 10, 5, 10, 2, 2, 3, 4, 5, 5, 7, 7, 8, 9, 7, 12, 12 };
Dictionary<int, int> duplicateNumbers = new Dictionary<int, int>();
int count=1;
for (int i = 0; i < array.Length; i++)
        for (int j = i; j < array.Length-1; j++)
            if (array[i] == array[j+1])
        if (count > 1)
            duplicateNumbers.Add(array[i], count);
foreach (var num in duplicateNumbers)
    Console.WriteLine("Duplicate numbers, NUMBER-{0}, OCCURRENCE- {1}",num.Key,num.Value);

What's the difference between Visual Studio Community and other, paid versions?

Visual Studio Community is same (almost) as professional edition. What differs is that VS community do not have TFS features, and the licensing is different. As stated by @Stefan.

The different versions on VS are compared here -

enter image description here

Bootstrap : TypeError: $(...).modal is not a function

I was getting the same error because of jquery CDN (<script src=""></script>) was added two times in the HTML head.

How do I get the total number of unique pairs of a set in the database?

What you're looking for is n choose k. Basically:

enter image description here

For every pair of 100 items, you'd have 4,950 combinations - provided order doesn't matter (AB and BA are considered a single combination) and you don't want to repeat (AA is not a valid pair).

How to make/get a multi size .ico file?

I found an app for Mac OSX called ICOBundle that allows you to easily drop a selection of ico files in different sizes onto the, prompts you for a folder destination and file name, and it creates the multi-icon .ico file.

Now if it were only possible to mix-in an animated gif version into that one file it'd be a complete icon set, sadly not possible and requires a separate file and code snippet.

How to concatenate text from multiple rows into a single text string in SQL server?

This method applies to Teradata Aster database only as it utilizes its NPATH function.

Again, we have table Students

SubjectID       StudentName
----------      -------------
1               Mary
1               John
1               Sam
2               Alaina
2               Edward

Then with NPATH it is just single SELECT:

SELECT * FROM npath(
  ON Students
  ORDER BY StudentName
    'true' as A
    FIRST(SubjectID of A) as SubjectID,
    ACCUMULATE(StudentName of A) as StudentName


SubjectID       StudentName
----------      -------------
1               [John, Mary, Sam]
2               [Alaina, Edward]

Why Anaconda does not recognize conda command?

I suspect you forget to export PATH, anaconda/bin must be added in your $PATH. (Linux, OSX common problem). On Windows make sure you run install and commands as administrator.

What is "Linting"?

Linting is the process of checking the source code for Programmatic as well as Stylistic errors. This is most helpful in identifying some common and uncommon mistakes that are made during coding.

A Lint or a Linter is a program that supports linting (verifying code quality). They are available for most languages like JavaScript, CSS, HTML, Python, etc..

Some of the useful linters are JSLint, CSSLint, JSHint, Pylint

How to Generate a random number of fixed length using JavaScript?

parseInt(Math.random().toString().slice(2,Math.min(length+2, 18)), 10); // 18 -> due to max digits in Math.random

Update: This method has few flaws: - Sometimes the number of digits might be lesser if its left padded with zeroes.

How to map calculated properties with JPA and Hibernate

JPA doesn't offer any support for derived property so you'll have to use a provider specific extension. As you mentioned, @Formula is perfect for this when using Hibernate. You can use an SQL fragment:

private float finalPrice;

Or even complex queries on other tables:

@Formula("(select min(o.creation_date) from Orders o where o.customer_id = id)")
private Date firstOrderDate;

Where id is the id of the current entity.

The following blog post is worth the read: Hibernate Derived Properties - Performance and Portability.

Without more details, I can't give a more precise answer but the above link should be helpful.

See also:

How to add bootstrap in angular 6 project?

For Angular Version 11+


The styles and scripts options in your angular.json configuration now allow to reference a package directly:

before: "styles": ["../node_modules/bootstrap/dist/css/bootstrap.css"]
after: "styles": ["bootstrap/dist/css/bootstrap.css"]

          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/ng6",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/",
            "assets": [
            "styles": [

            "scripts": [

Angular Version 10 and below

You are using Angular v6 not 2

Angular v6 Onwards

CLI projects in angular 6 onwards will be using angular.json instead of .angular-cli.json for build and project configuration.

Each CLI workspace has projects, each project has targets, and each target can have configurations.Docs

. {
  "projects": {
    "my-project-name": {
      "projectType": "application",
      "architect": {
        "build": {
          "configurations": {
            "production": {},
            "demo": {},
            "staging": {},
        "serve": {},
        "extract-i18n": {},
        "test": {},
    "my-project-name-e2e": {}

execute npm install bootstrap@4 jquery --save
The JavaScript parts of Bootstrap are dependent on jQuery. So you need the jQuery JavaScript library file too.

In your angular.json add the file paths to the styles and scripts array in under build target
NOTE: Before v6 the Angular CLI project configuration was stored in <PATH_TO_PROJECT>/.angular-cli.json. As of v6 the location of the file changed to angular.json. Since there is no longer a leading dot, the file is no longer hidden by default and is on the same level.
which also means that file paths in angular.json should not contain leading dots and slash

i.e you can provide an absolute path instead of a relative path

In .angular-cli.json file Path was "../node_modules/"
In angular.json it is "node_modules/"

 "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/ng6",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/",
            "assets": [
            "styles": [
            "scripts": ["node_modules/jquery/dist/jquery.min.js",

Add files from CDN (Content Delivery Network) to your project CDN LINK

Open file src/index.html and insert

the <link> element at the end of the head section to include the Bootstrap CSS file
a <script> element to include jQuery at the bottom of the body section
a <script> element to include Popper.js at the bottom of the body section
a <script> element to include the Bootstrap JavaScript file at the bottom of the body section

  <!doctype html>
      <meta charset="utf-8">
      <base href="/">
      <meta name="viewport" content="width=device-width, initial-scale=1">
      <link rel="icon" type="image/x-icon" href="favicon.ico">
      <link rel="stylesheet" href="" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
      <script src="" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>

Execute npm install bootstrap
In src/styles.css add the following line:

@import "~bootstrap/dist/css/bootstrap.css";

ng-bootstrap It contains a set of native Angular directives based on Bootstrap’s markup and CSS. As a result, it's not dependent on jQuery or Bootstrap’s JavaScript

npm install --save @ng-bootstrap/ng-bootstrap

After Installation import it in your root module and register it in @NgModule imports` array

import {NgbModule} from '@ng-bootstrap/ng-bootstrap';
  declarations: [AppComponent, ...],
  imports: [NgbModule.forRoot(), ...],
  bootstrap: [AppComponent]

ng-bootstrap requires Bootstrap's 4 css to be added in your project. you need to Install it explicitly via:
npm install bootstrap@4 --save In your angular.json add the file paths to the styles array in under build target

   "styles": [

P.S Do Restart Your server

`ng serve || npm start`

Java 8 List<V> into Map<K, V>

For example, if you want convert object fields to map:

Example object:

class Item{
        private String code;
        private String name;

        public Item(String code, String name) {
            this.code = code;
   = name;

        //getters and setters

And operation convert List To Map:

List<Item> list = new ArrayList<>();
list.add(new Item("code1", "name1"));
list.add(new Item("code2", "name2"));

Map<String,String> map =
     .collect(Collectors.toMap(Item::getCode, Item::getName));

Change the fill color of a cell based on a selection from a Drop Down List in an adjacent cell

You can leverage Conditional Formatting as follows.

  1. In cell H8 select Format > Conditional Formatting...
  2. In Condition1, select Formula Is in first drop down menu
  3. In the next textbox type =I8="Elementary"
  4. Select Format... and select the color you want etc.
  5. Select Add>> and repeat steps 1 to 4

Note that you can only have (in excel 2003) three separate conditions so you will only be able to have different formatting for three items in the drop down menu. If the idea is to make them visually distinct then (maybe) having no color for one of the selections is not a problem?

If the cell is never blank, you can use format (not conditional) to get 4 distinct visuals.

List of Java processes

To know the list of java running on the linux machine. ps -e | grep java