Programs & Examples On #Nine patch

A NinePatch is a stretchable bitmap image, which Android will automatically resize to accommodate the contents of the View in which you have placed it as the background. The four corners are unscaled; the four edges are scaled in one axis, and the middle is scaled in both axes.

How to change the spinner background in Android?

You need to create a new personalized layout for your spinner items, like this, I will name it:


<TextView xmlns:android=""
    android:textColor="#ff0000" />

Then on your spinner declaration, you need to make your spinner use the new layout in the adapter:

ArrayAdapter adapter = ArrayAdapter.createFromResource(this,
R.layout.spinner_item, YOUR_SPINNER_CONTENT);

To personalize elements from the dropdown list, you need to create another layout, I will name it spinner_dropdown_item.xml:

<CheckedTextView xmlns:android=""

and then on the adapter:

ArrayAdapter adapter = ArrayAdapter.createFromResource(this,
R.layout.spinner_item, YOUR_SPINNER_CONTENT);

LINQ Aggregate algorithm explained

A short and essential definition might be this: Linq Aggregate extension method allows to declare a sort of recursive function applied on the elements of a list, the operands of whom are two: the elements in the order in which they are present into the list, one element at a time, and the result of the previous recursive iteration or nothing if not yet recursion.

In this way you can compute the factorial of numbers, or concatenate strings.

Good examples using java.util.logging

Should declare logger like this:

private final static Logger LOGGER = Logger.getLogger(MyClass.class.getName());

so if you refactor your class name it follows.

I wrote an article about java logger with examples here.

insert a NOT NULL column to an existing table


How to scale images to screen size in Pygame

You can scale the image with pygame.transform.scale:

import pygame
picture = pygame.image.load(filename)
picture = pygame.transform.scale(picture, (1280, 720))

You can then get the bounding rectangle of picture with

rect = picture.get_rect()

and move the picture with

rect = rect.move((x, y))
screen.blit(picture, rect)

where screen was set with something like

screen = pygame.display.set_mode((1600, 900))

To allow your widgets to adjust to various screen sizes, you could make the display resizable:

import os
import pygame
from pygame.locals import *

screen = pygame.display.set_mode((500, 500), HWSURFACE | DOUBLEBUF | RESIZABLE)
pic = pygame.image.load("image.png")
screen.blit(pygame.transform.scale(pic, (500, 500)), (0, 0))
while True:
    event = pygame.event.wait()
    if event.type == QUIT:
    elif event.type == VIDEORESIZE:
        screen = pygame.display.set_mode(
            event.dict['size'], HWSURFACE | DOUBLEBUF | RESIZABLE)
        screen.blit(pygame.transform.scale(pic, event.dict['size']), (0, 0))

How can I capitalize the first letter of each word in a string?

A quick function worked for Python 3

Python 3.6.9 (default, Nov  7 2019, 10:44:02) 
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> capitalizeFirtChar = lambda s: s[:1].upper() + s[1:]
>>> print(capitalizeFirtChar('??????? ????? ????????. ???????? ?? ?????? ? ??????????????!'))
??????? ????? ????????. ???????? ?? ?????? ? ??????????????!
>>> print(capitalizeFirtChar('??? ???? ?????? ???????! ??? ???? ?????? ????? ???.'))
??? ???? ?????? ???????! ??? ???? ?????? ????? ???.
>>> print(capitalizeFirtChar('faith and Labour make Dreams come true.'))
Faith and Labour make Dreams come true.

Javascript Equivalent to PHP Explode()

With no intentions to critique John Hartsock, just in case the number of delimiters may vary for anyone using the given code, I would formally suggest to use this instead...

var mystr = '0000000020C90037:TEMP:data';
var myarr = mystr.split(":");
var arrlen = myarr.length;
var myvar = myarr[arrlen-2] + ":" + myarr[arrlen-1];

Javascript - How to detect if document has loaded (IE 7/Firefox 3)

Mozila Firefox says that onreadystatechange is an alternative to DOMContentLoaded.

// alternative to DOMContentLoaded
document.onreadystatechange = function () {
    if (document.readyState == "complete") {

In DOMContentLoaded the Mozila's doc says:

The DOMContentLoaded event is fired when the document has been completely loaded and parsed, without waiting for stylesheets, images, and subframes to finish loading (the load event can be used to detect a fully-loaded page).

I think load event should be used for a full document+resources loading.

Only get hash value using md5sum (without filename)

md5=$(md5sum < $file | tr -d ' -')

Evenly distributing n points on a sphere

OR... to place 20 points, compute the centers of the icosahedronal faces. For 12 points, find the vertices of the icosahedron. For 30 points, the mid point of the edges of the icosahedron. you can do the same thing with the tetrahedron, cube, dodecahedron and octahedrons: one set of points is on the vertices, another on the center of the face and another on the center of the edges. They cannot be mixed, however.

How to get the children of the $(this) selector?

You could also use


which would return all imgs that are descendants of the div

Compare cell contents against string in Excel

You can use the EXACT Function for exact string comparisons.

=IF(EXACT(A1, "ENG"), 1, 0)

How to get data from observable in angular2

You need to subscribe to the observable and pass a callback that processes emitted values

this.myService.getConfig().subscribe(val => console.log(val));

Why is my method undefined for the type object?

Change your main to:

public static void main(String[] args) {
    EchoServer echoServer = new EchoServer();

When you declare Object EchoServer0; you have a few mistakes.

  1. EchoServer0 is of type Object, therefore it doesn't have the method listen().
  2. You will also need to create an instance of it with new.
  3. Another problem, this is only regarding naming conventions, you should call your variables starting by lower case letters, echoServer0 instead of EchoServer0. Uppercase names are usually for class names.
  4. You should not create a variable with the same name as its class. It is confusing.

'mvn' is not recognized as an internal or external command, operable program or batch file

I did all of this in Windows 10 and still had a problem. In the end it turned out that the path to the Maven home folder was not exactly what was expected in many of these answers as it turned out to be /apache-maven-3.6.3-bin/apache-maven-3.6.3. Once I corrected this for both the system variables and the PATH variable, it worked. In short, if you have set the environment variables up as directed and it still won't work, I would double check to make sure the variables really point to the exact path to the Maven home folder and the bin folder on your machine.

jQuery append() vs appendChild()

appendChild is a DOM vanilla-js function.

append is a jQuery function.

They each have their own quirks.

What requests do browsers' "F5" and "Ctrl + F5" refreshes generate?

I've implemented cross-browser compatible page to test browser's refresh behavior (here is the source code) and get results similar to @some, but for modern browsers:

enter image description here

How to do an INNER JOIN on multiple columns

If you want to search on both FROM and TO airports, you'll want to join on the Airports table twice - then you can use both from and to tables in your results set:

   Airports fromAirports on Flights.fairport = fromAirports.code
   Airports toAirports on Flights.tairport = toAirports.code

Wrap text in <td> tag

I had some of my tds with:

white-space: pre;

This solved it for me:

white-space: pre-wrap;

Why does JPA have a @Transient annotation?

Java's transient keyword is used to denote that a field is not to be serialized, whereas JPA's @Transient annotation is used to indicate that a field is not to be persisted in the database, i.e. their semantics are different.

How to execute a function when page has fully loaded?

Usually you can use window.onload, but you may notice that recent browsers don't fire window.onload when you use the back/forward history buttons.

Some people suggest weird contortions to work around this problem, but really if you just make a window.onunload handler (even one that doesn't do anything), this caching behavior will be disabled in all browsers. The MDC documents this "feature" pretty well, but for some reason there are still people using setInterval and other weird hacks.

Some versions of Opera have a bug that can be worked around by adding the following somewhere in your page:

<script>history.navigationMode = 'compatible';</script>

If you're just trying to get a javascript function called once per-view (and not necessarily after the DOM is finished loading), you can do something like this:

<img src="javascript:location.href='javascript:yourFunction();';">

For example, I use this trick to preload a very large file into the cache on a loading screen:

<img src="bigfile"

IIS error, Unable to start debugging on the webserver

In my case it was the lack of debug="true" in web.config (system.web -> compilation).


   <compilation debug="true" targetFramework="4.5.2" />

Google Maps API v3: How do I dynamically change the marker icon?

You can also use a circle as a marker icon, for example:

var oMarker = new google.maps.Marker({
    position: latLng,
    sName: "Marker Name",
    map: map,
    icon: {
        path: google.maps.SymbolPath.CIRCLE,
        scale: 8.5,
        fillColor: "#F00",
        fillOpacity: 0.4,
        strokeWeight: 0.4

and then, if you want to change the marker dynamically (like on mouseover), you can, for example:

            path: google.maps.SymbolPath.CIRCLE,
            scale: 10,
            fillColor: "#00F",
            fillOpacity: 0.8,
            strokeWeight: 1

What causes HttpHostConnectException?

You must set proxy server for gradle at some time, you can try to change the proxy server ip address in which is under .gradle document

Converting between datetime and Pandas Timestamp objects

You can use the to_pydatetime method to be more explicit:

In [11]: ts = pd.Timestamp('2014-01-23 00:00:00', tz=None)

In [12]: ts.to_pydatetime()
Out[12]: datetime.datetime(2014, 1, 23, 0, 0)

It's also available on a DatetimeIndex:

In [13]: rng = pd.date_range('1/10/2011', periods=3, freq='D')

In [14]: rng.to_pydatetime()
array([datetime.datetime(2011, 1, 10, 0, 0),
       datetime.datetime(2011, 1, 11, 0, 0),
       datetime.datetime(2011, 1, 12, 0, 0)], dtype=object)

Multiple file-extensions searchPattern for System.IO.Directory.GetFiles

The easy-to-remember, lazy and perhaps imperfect solution:

Directory.GetFiles(dir, "*.dll").Union(Directory.GetFiles(dir, "*.exe"))

Comparing strings in Java

Using the == operator will compare the references to the strings not the string themselves.

Ok, you have to toString() the Editable. I loaded up some of the code I had before that dealt with this situation.

String passwd1Text = passw1.getText().toString();
String passwd2Text = passw2.getText().toString();

if (passwd1Text.equals(passwd2Text))

Creating a zero-filled pandas data frame

Similar to @Shravan, but without the use of numpy:

  height = 10
  width = 20
  df_0 = pd.DataFrame(0, index=range(height), columns=range(width))

Then you can do whatever you want with it:

post_instantiation_fcn = lambda x: str(x)
df_ready_for_whatever = df_0.applymap(post_instantiation_fcn) Repeater get current index, pointer, or counter

Add a label control to your Repeater's ItemTemplate. Handle OnItemCreated event.


<asp:Repeater ID="rptr" runat="server" OnItemCreated="RepeaterItemCreated">
        <div id="width:50%;height:30px;background:#0f0a0f;">
            <asp:Label ID="lblSr" runat="server" 
               style="width:30%;float:left;text-align:right;text-indent:-2px;" />
               style="width:65%;float:right;text-align:left;text-indent:-2px;" >
            <%# Eval("Item") %>

Code Behind:

    protected void RepeaterItemCreated(object sender, RepeaterItemEventArgs e)
        Label l = e.Item.FindControl("lblSr") as Label;
        if (l != null)
            l.Text = e.Item.ItemIndex + 1+"";

How to get last 7 days data from current datetime to last 7 days in sql server

If you want to do it using Pentaho DI, you can use "Modified JavaScript" Step and write the below function:

dateAdd(d1, "d", -7);  // d1 is the current date and "d" is the date identifier

Check the image below: [Assuming current date is : 22 December 2014]

enter image description here

Hope it helps :)

How to get current CPU and RAM usage in Python?

This aggregate all the goodies: psutil + os to get Unix & Windows compatibility: That allows us to get:

  1. CPU
  2. memory
  3. disk


import os
import psutil  # need: pip install psutil

In [32]: psutil.virtual_memory()
Out[32]: svmem(total=6247907328, available=2502328320, percent=59.9, used=3327135744, free=167067648, active=3671199744, inactive=1662668800,     buffers=844783616, cached=1908920320, shared=123912192, slab=613048320)

In [33]: psutil.virtual_memory().percent
Out[33]: 60.0

In [34]: psutil.cpu_percent()
Out[34]: 5.5

In [35]: os.sep
Out[35]: '/'

In [36]: psutil.disk_usage(os.sep)
Out[36]: sdiskusage(total=50190790656, used=41343860736, free=6467502080, percent=86.5)

In [37]: psutil.disk_usage(os.sep).percent
Out[37]: 86.5

Count textarea characters

var maxchar = 10;_x000D_
$('#message').after('<span id="count" class="counter"></span>');_x000D_
$('#count').html(maxchar+' of '+maxchar);_x000D_
$('#message').attr('maxlength', maxchar);_x000D_
$('#message').on("keydown", function(e){_x000D_
 var len =  $('#message').val().length;_x000D_
 if (len >= maxchar && e.keyCode != 8)_x000D_
 else if(len <= maxchar && e.keyCode == 8){_x000D_
  if(len <= maxchar && len != 0)_x000D_
      $('#count').html(maxchar+' of '+(maxchar - len +1));_x000D_
     else if(len == 0)_x000D_
      $('#count').html(maxchar+' of '+(maxchar - len));_x000D_
   $('#count').html(maxchar+' of '+(maxchar - len-1)); _x000D_
<script src=""></script>_x000D_
<textarea id="message" name="text"></textarea>

How to save a figure in MATLAB from the command line?

imwrite(A,filename) writes image data A to the file specified by filename, inferring the file format from the extension

How to drop all tables from a database with one SQL query?

If you want to use only one SQL query to delete all tables you can use this:

EXEC sp_MSforeachtable @command1 = "DROP TABLE ?"

This is a hidden Stored Procedure in sql server, and will be executed for each table in the database you're connected.

Note: You may need to execute the query a few times to delete all tables due to dependencies.

Note2: To avoid the first note, before running the query, first check if there foreign keys relations to any table. If there are then just disable foreign key constraint by running the query bellow:


When to use single quotes, double quotes, and backticks in MySQL

There are two types of quotes in MySQL:

  1. ' for enclosing string literals
  2. ` for enclosing identifiers such as table and column names

And then there is " which is a special case. It could be used for one of above-mentioned purposes at a time depending on MySQL server's sql_mode:

  1. By default the " character can be used to enclose string literals just like '
  2. In ANSI_QUOTES mode the " character can be used to enclose identifiers just like `

The following query will produce different results (or errors) depending on SQL mode:

SELECT "column" FROM table WHERE foo = "bar"

ANSI_QUOTES disabled

The query will select the string literal "column" where column foo is equal to string "bar"


The query will select the column column where column foo is equal to column bar

When to use what

  • I suggest that you avoid using " so that your code becomes independent of SQL modes
  • Always quote identifiers since it is a good practice (quite a few questions on SO discuss this)

How can I create a text box for a note in markdown?

With GitHub, I usually insert a blockquote.

> **_NOTE:_**  The note content.


NOTE: The note content.

Of course, there is always plain HTML...

Use SQL Server Management Studio to connect remotely to an SQL Server Express instance hosted on an Azure Virtual Machine

I too struggled with something similar. My guess is your actual problem is connecting to a SQL Express instance running on a different machine. The steps to do this can be summarized as follows:

  1. Ensure SQL Express is configured for SQL Authentication as well as Windows Authentication (the default). You do this via SQL Server Management Studio (SSMS) Server Properties/Security
  2. In SSMS create a new login called "sqlUser", say, with a suitable password, "sql", say. Ensure this new login is set for SQL Authentication, not Windows Authentication. SSMS Server Security/Logins/Properties/General. Also ensure "Enforce password policy" is unchecked
  3. Under Properties/Server Roles ensure this new user has the "sysadmin" role
  4. In SQL Server Configuration Manager SSCM (search for SQLServerManagerxx.msc file in Windows\SysWOW64 if you can't find SSCM) under SQL Server Network Configuration/Protocols for SQLExpress make sure TCP/IP is enabled. You can disable Named Pipes if you want
  5. Right-click protocol TCP/IP and on the IPAddresses tab, ensure every one of the IP addresses is set to Enabled Yes, and TCP Port 1433 (this is the default port for SQL Server)
  6. In Windows Firewall (WF.msc) create two new Inbound Rules - one for SQL Server and another for SQL Browser Service. For SQL Server you need to open TCP Port 1433 (if you are using the default port for SQL Server) and very importantly for the SQL Browser Service you need to open UDP Port 1434. Name these two rules suitably in your firewall
  7. Stop and restart the SQL Server Service using either SSCM or the Services.msc snap-in
  8. In the Services.msc snap-in make sure SQL Browser Service Startup Type is Automatic and then start this service

At this point you should be able to connect remotely, using SQL Authentication, user "sqlUser" password "sql" to the SQL Express instance configured as above. A final tip and easy way to check this out is to create an empty text file with the .UDL extension, say "Test.UDL" on your desktop. Double-clicking to edit this file invokes the Microsoft Data Link Properties dialog with which you can quickly test your remote SQL connection

How to replace text of a cell based on condition in excel

You can use the IF statement in a new cell to replace text, such as:

=IF(A4="C", "Other", A4)

This will check and see if cell value A4 is "C", and if it is, it replaces it with the text "Other"; otherwise, it uses the contents of cell A4.


Assuming that the Employee_Count values are in B1-B10, you can use this:

=IF(B1=LARGE($B$1:$B$10, 10), "Other", B1)

This function doesn't even require the data to be sorted; the LARGE function will find the 10th largest number in the series, and then the rest of the formula will compare against that.

Disabling the button after once click

protected void Page_Load(object sender, EventArgs e)
        // prevent user from making operation twice
                               "this.disabled=true;" + GetPostBackEventReference(btnSave).ToString() + ";");

        // ... etc. 

Fast way of finding lines in one file that are not in another?

The way I usually do this is using the --suppress-common-lines flag, though note that this only works if your do it in side-by-side format.

diff -y --suppress-common-lines file1.txt file2.txt

Sending a file over TCP sockets in Python

Put file inside while True like so

while True:
     f = open('torecv.png','wb')
     c, addr = s.accept()     # Establish connection with client.
     print 'Got connection from', addr
     print "Receiving..."
     l = c.recv(1024)
     while (l):
         print "Receiving..."
         l = c.recv(1024)
     print "Done Receiving"
     c.send('Thank you for connecting')

How to convert a string or integer to binary in Ruby?

In ruby Integer class, to_s is defined to receive non required argument radix called base, pass 2 if you want to receive binary representation of a string.

Here is a link for an official documentation of String#to_s

  1.upto(10).each { |n|  puts n.to_s(2) }

When to use Interface and Model in TypeScript / Angular

As @ThierryTemplier said for receiving data from server and also transmitting model between components (to keep intellisense list and make design time error), it's fine to use interface but I think for sending data to server (DTOs) it's better to use class to take advantages of auto mapping DTO from model.

How to make an app's background image repeat

There is a property in the drawable xml to do it. android:tileMode="repeat"

See this site:

TypeScript Objects as Dictionary types as in C#

Lodash has a simple Dictionary implementation and has good TypeScript support

Install Lodash:

npm install lodash @types/lodash --save

Import and usage:

import { Dictionary } from "lodash";
let properties : Dictionary<string> = {
    "key": "value"        

How to open mail app from Swift

You should try sending with built-in mail composer, and if that fails, try with share:

func contactUs() {

    let email = "[email protected]" // insert your email here
    let subject = "your subject goes here"
    let bodyText = "your body text goes here"

    if MFMailComposeViewController.canSendMail() {

        let mailComposerVC = MFMailComposeViewController()
        mailComposerVC.mailComposeDelegate = self as? MFMailComposeViewControllerDelegate

        mailComposerVC.setMessageBody(bodyText, isHTML: false)

        self.present(mailComposerVC, animated: true, completion: nil)

    } else {
        print("Device not configured to send emails, trying with share ...")

        let coded = "mailto:\(email)?subject=\(subject)&body=\(bodyText)".addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)
        if let emailURL = URL(string: coded!) {
            if #available(iOS 10.0, *) {
                if UIApplication.shared.canOpenURL(emailURL) {
          , options: [:], completionHandler: { (result) in
                        if !result {
                            print("Unable to send email.")
            else {
                UIApplication.shared.openURL(emailURL as URL)

Capitalize first letter. MySQL

This is working nicely.

UPDATE state SET name = CONCAT(UCASE(LEFT(name, 1)), LCASE(SUBSTRING(name, 2)));

Get index of clicked element in collection with jQuery

Just do this way:-

$('ul li').on('click', function(e) {


$('ul li').click(function() {

Remove pattern from string with gsub

The following code works on your example :

gsub(".*_", "", a)

Difference of keywords 'typename' and 'class' in templates?

For naming template parameters, typename and class are equivalent. §14.1.2:

There is no semantic difference between class and typename in a template-parameter.

typename however is possible in another context when using templates - to hint at the compiler that you are referring to a dependent type. §14.6.2:

A name used in a template declaration or definition and that is dependent on a template-parameter is assumed not to name a type unless the applicable name lookup finds a type name or the name is qualified by the keyword typename.


typename some_template<T>::some_type

Without typename the compiler can't tell in general whether you are referring to a type or not.

How to get status code from webclient?

Erik's answer doesn't work on Windows Phone as is. The following does:

class WebClientEx : WebClient
    private WebResponse m_Resp = null;

    protected override WebResponse GetWebResponse(WebRequest Req, IAsyncResult ar)
            this.m_Resp = base.GetWebResponse(request);
        catch (WebException ex)
            if (this.m_Resp == null)
                this.m_Resp = ex.Response;
        return this.m_Resp;

    public HttpStatusCode StatusCode
            if (m_Resp != null && m_Resp is HttpWebResponse)
                return (m_Resp as HttpWebResponse).StatusCode;
                return HttpStatusCode.OK;

At least it does when using OpenReadAsync; for other xxxAsync methods, careful testing would be highly recommended. The framework calls GetWebResponse somewhere along the code path; all one needs to do is capture and cache the response object.

The fallback code is 200 in this snippet because genuine HTTP errors - 500, 404, etc - are reported as exceptions anyway. The purpose of this trick is to capture non-error codes, in my specific case 304 (Not modified). So the fallback assumes that if the status code is somehow unavailable, at least it's a non-erroneous one.

Character reading from file in Python

It is also possible to read an encoded text file using the python 3 read method:

f = open (file.txt, 'r', encoding='utf-8')
text =

With this variation, there is no need to import any additional libraries

Print string to text file

text_file = open("Output.txt", "w")
text_file.write("Purchase Amount: %s" % TotalAmount)

If you use a context manager, the file is closed automatically for you

with open("Output.txt", "w") as text_file:
    text_file.write("Purchase Amount: %s" % TotalAmount)

If you're using Python2.6 or higher, it's preferred to use str.format()

with open("Output.txt", "w") as text_file:
    text_file.write("Purchase Amount: {0}".format(TotalAmount))

For python2.7 and higher you can use {} instead of {0}

In Python3, there is an optional file parameter to the print function

with open("Output.txt", "w") as text_file:
    print("Purchase Amount: {}".format(TotalAmount), file=text_file)

Python3.6 introduced f-strings for another alternative

with open("Output.txt", "w") as text_file:
    print(f"Purchase Amount: {TotalAmount}", file=text_file)

Exception : peer not authenticated

if you are in dev mode with not valid certificate, why not just set weClient.setUseInsecureSSL(true). works for me

How to add new column to MYSQL table?

Something like:

$db = mysqli_connect("localhost", "user", "password", "database");
$name = $db->mysqli_real_escape_string($name);
$query = 'ALTER TABLE assesment ADD ' . $name . ' TINYINT NOT NULL DEFAULT \'0\'';
if($db->query($query)) {
    echo "It worked";

Haven't tested it but should work.

Is "&#160;" a replacement of "&nbsp;"?

Those do both mean non-breaking space, yes. &#xA0; is another synonym, in hex.

How do I execute code AFTER a form has loaded?

I sometimes use (in Load)

this.BeginInvoke((MethodInvoker) delegate {
  // some code


this.BeginInvoke((MethodInvoker) this.SomeMethod);

(change "this" to your form variable if you are handling the event on an instance other than "this").

This pushes the invoke onto the windows-forms loop, so it gets processed when the form is processing the message queue.

[updated on request]

The Control.Invoke/Control.BeginInvoke methods are intended for use with threading, and are a mechanism to push work onto the UI thread. Normally this is used by worker threads etc. Control.Invoke does a synchronous call, where-as Control.BeginInvoke does an asynchronous call.

Normally, these would be used as:

  // this code running on a worker thread...
  string newText = ExpensiveMethod(); // perhaps a DB/web call

  // now ask the UI thread to update itself
  this.Invoke((MethodInvoker) delegate {
      // this code runs on the UI thread!
      this.Text = newText;

It does this by pushing a message onto the windows message queue; the UI thread (at some point) de-queues the message, processes the delegate, and signals the worker that it completed... so far so good ;-p

OK; so what happens if we use Control.Invoke / Control.BeginInvoke on the UI thread? It copes... if you call Control.Invoke, it is sensible enough to know that blocking on the message queue would cause an immediate deadlock - so if you are already on the UI thread it simply runs the code immediately... so that doesn't help us...

But Control.BeginInvoke works differently: it always pushes work onto the queue, even it we are already on the UI thread. This makes a really simply way of saying "in a moment", but without the inconvenience of timers etc (which would still have to do the same thing anyway!).

htaccess redirect if URL contains a certain string

RewriteCond %{REQUEST_URI} foobar
RewriteRule .* index.php

or some variant thereof.

Start systemd service after specific service?

After= dependency is only effective when service including After= and service included by After= are both scheduled to start as part of your boot up.



This way, if both a.service and b.service are enabled, then systemd will order b.service after a.service.

If I am not misunderstanding, what you are asking is how to start b.service when a.service starts even though b.service is not enabled.

The directive for this is Wants= or Requires= under [Unit].


The difference between Wants= and Requires= is that with Requires=, a failure to start b.service will cause the startup of a.service to fail, whereas with Wants=, a.service will start even if b.service fails. This is explained in detail on the man page of .unit.

How to Execute SQL Server Stored Procedure in SQL Developer?

    EXECUTE [or EXEC] procedure_name
  @parameter_1_Name = 'parameter_1_Value', 
    @parameter_2_name = 'parameter_2_value',
    @parameter_z_name = 'parameter_z_value'

Parsing JSON using

     * This method takes in JSON in the form returned by javascript's
     * JSON.stringify(Object) and returns a string->string dictionary.
     * This method may be of use when the format of the json is unknown.
     * You can modify the delimiters, etc pretty easily in the source
     * (sorry I didn't abstract it--I have a very specific use).
    public static Dictionary<string, string> jsonParse(string rawjson)
        Dictionary<string, string> outdict = new Dictionary<string, string>();
        StringBuilder keybufferbuilder = new StringBuilder();
        StringBuilder valuebufferbuilder = new StringBuilder();
        StringReader bufferreader = new StringReader(rawjson);

        int s = 0;
        bool reading = false;
        bool inside_string = false;
        bool reading_value = false;
        //break at end (returns -1)
        while (s >= 0)
            s = bufferreader.Read();
            //opening of json
            if (!reading)
                if ((char)s == '{' && !inside_string && !reading) reading = true;
                //if we find a quote and we are not yet inside a string, advance and get inside
                if (!inside_string)
                    //read past the quote
                    if ((char)s == '\"') inside_string = true;
                if (inside_string)
                    //if we reached the end of the string
                    if ((char)s == '\"')
                        inside_string = false;
                        s = bufferreader.Read(); //advance pointer
                        if ((char)s == ':')
                            reading_value = true;
                        if (reading_value && (char)s == ',')
                            //we know we just ended the line, so put itin our dictionary
                            if (!outdict.ContainsKey(keybufferbuilder.ToString())) outdict.Add(keybufferbuilder.ToString(), valuebufferbuilder.ToString());
                            //and clear the buffers
                            reading_value = false;
                        if (reading_value && (char)s == '}')
                            //we know we just ended the line, so put itin our dictionary
                            if (!outdict.ContainsKey(keybufferbuilder.ToString())) outdict.Add(keybufferbuilder.ToString(), valuebufferbuilder.ToString());
                            //and clear the buffers
                            reading_value = false;
                            reading = false;
                        if (reading_value)
                    switch ((char)s)
                        case ':':
                            reading_value = true;
                            if (reading_value)
        return outdict;

IntelliJ, can't start simple web application: Unable to ping server at localhost:1099

I meet this question when i use intellij 15.0,then i update to 15.02 version. after that, I edit configurations and reset the Default JRE to my own JRE.It works well for me;

How to use callback with useState hook in react

Another way to achieve this:

const [Name, setName] = useState({val:"", callback: null});_x000D_
  const {callback} = Name;_x000D_
  callback && callback();_x000D_
}, [Name]);_x000D_
setName({val:'foo', callback: ()=>setName({val: 'then bar'})})

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

Try to use GMT instead of UTC. They refer to the same time zone, yet the name GMT is more common and might work.

HttpServletRequest - how to obtain the referring URL?

The URLs are passed in the request: request.getRequestURL().

If you mean other sites that are linking to you? You want to capture the HTTP Referrer, which you can do by calling:


Converting array to list in Java

you have to cast in to array

Arrays.asList((Object[]) array)

Get array of object's keys

In case you're here looking for something to list the keys of an n-depth nested object as a flat array:

const getObjectKeys = (obj, prefix = '') => {_x000D_
  return Object.entries(obj).reduce((collector, [key, val]) => {_x000D_
    const newKeys = [ ...collector, prefix ? `${prefix}.${key}` : key ]_x000D_
    if ( === '[object Object]') {_x000D_
      const newPrefix = prefix ? `${prefix}.${key}` : key_x000D_
      const otherKeys = getObjectKeys(val, newPrefix)_x000D_
      return [ ...newKeys, ...otherKeys ]_x000D_
    return newKeys_x000D_
  }, [])_x000D_
console.log(getObjectKeys({a: 1, b: 2, c: { d: 3, e: { f: 4 }}}))

What are the differences between C, C# and C++ in terms of real-world applications?

C is the core language that most closely resembles and directly translates into CPU machine code. CPUs follow instructions that move, add, logically combine, compare, jump, push and pop. C does exactly this using much easier syntax. If you study the disassembly, you can learn to write C code that is just as fast and compact as assembly. It is my preferred language on 8 bit micro controllers with limited memory. If you write a large PC program in C you will get into trouble because of its limited organization. That is where object oriented programming becomes powerful. The ability of C++ and C# classes to contain data and functions together enforces organization which in turn allows more complex operability over C. C++ was essential for quick processing in the past when CPUs only had one core. I am beginning to learn C# now. Its class only structure appears to enforce a higher degree of organization than C++ which should ultimately lead to faster development and promote code sharing. C# is not interpreted like VB. It is partially compiled at development time and then further translated at run time to become more platform friendly.

Data at the root level is invalid



should be:


LoadXml() is for loading an XML string, not a file name.

How to connect to LocalDB in Visual Studio Server Explorer?

Scenario: Windows 8.1, VS2013 Ultimate, SQL Express Installed and running, SQL Server Browser Disabled. This worked for me:

  1. First I enabled SQL Server Browser under services.
  2. In Visual Studio: Open the Package Manager Console then type: Enable-Migrations; Then Type Enable-Migrations -ContextTypeName YourContextDbName that created the Migrations folder in VS.
  3. Inside the Migrations folder you will find the "Configuration.cs" file, turn on automatic migrations by: AutomaticMigrationsEnabled = true;
  4. Run your application again, the environment creates a DefaultConnection and you will see the new tables from your context. This new connection points to the localdb. The created connection string shows: Data Source=(LocalDb)\v11.0 ... (more parameters and path to the created mdf file)

You can now create a new connection with Server name: (LocalDb)\v11.0 (hit refresh) Connect to a database: Select your new database under the dropdown.

I hope it helps.

What is the correct way to create a single-instance WPF application?

A time saving solution for C# Winforms...


using System;
using System.Windows.Forms;
// needs reference to Microsoft.VisualBasic
using Microsoft.VisualBasic.ApplicationServices;  

namespace YourNamespace
    public class SingleInstanceController : WindowsFormsApplicationBase
        public SingleInstanceController()
            this.IsSingleInstance = true;

        protected override void OnStartupNextInstance(StartupNextInstanceEventArgs e)
            e.BringToForeground = true;

        protected override void OnCreateMainForm()
            this.MainForm = new Form1();

    static class Program
        static void Main()
            string[] args = Environment.GetCommandLineArgs();
            SingleInstanceController controller = new SingleInstanceController();

Setting default values to null fields when mapping with Jackson

Only one proposed solution keeps the default-value when some-value:null was set explicitly (POJO readability is lost there and it's clumsy)

Here's how one can keep the default-value and never set it to null

public String someValue = "default-value";

public void setSomeValue(String s) {
    if (s != null) { 
        someValue = s; 

Java JTable getting the data of the selected row

You will find these methods in it:

getValueAt(int row, int column)

Use a mix of these to achieve your result.

Python send UDP packet

With Python3x, you need to convert your string to raw bytes. You would have to encode the string as bytes. Over the network you need to send bytes and not characters. You are right that this would work for Python 2x since in Python 2x, socket.sendto on a socket takes a "plain" string and not bytes. Try this:

print("UDP target IP:", UDP_IP)
print("UDP target port:", UDP_PORT)
print("message:", MESSAGE)

sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # UDP
sock.sendto(bytes(MESSAGE, "utf-8"), (UDP_IP, UDP_PORT))

Find the closest ancestor element that has a specific class

This solution should work for IE9 and up.

It's like jQuery's parents() method when you need to get a parent container which might be up a few levels from the given element, like finding the containing <form> of a clicked <button>. Looks through the parents until the matching selector is found, or until it reaches the <body>. Returns either the matching element or the <body>.

function parents(el, selector){
    var parent_container = el;
    do {
        parent_container = parent_container.parentNode;
    while( !parent_container.matches(selector) && parent_container !== document.body );

    return parent_container;

jQuery: Get height of hidden element in jQuery

You could also position the hidden div off the screen with a negative margin rather than using display:none, much like a the text indent image replacement technique.


left:  -2000px;
top: 0;

This way the height() is still available.

Get public/external IP address?

With .Net WebRequest:

  public static string GetPublicIP()
        string url = "";
        System.Net.WebRequest req = System.Net.WebRequest.Create(url);
        System.Net.WebResponse resp = req.GetResponse();
        System.IO.StreamReader sr = new System.IO.StreamReader(resp.GetResponseStream());
        string response = sr.ReadToEnd().Trim();
        string[] a = response.Split(':');
        string a2 = a[1].Substring(1);
        string[] a3 = a2.Split('<');
        string a4 = a3[0];
        return a4;

Reading multiple Scanner inputs

If every input asks the same question, you should use a for loop and an array of inputs:

Scanner dd = new Scanner(;
int[] vars = new int[3];

for(int i = 0; i < vars.length; i++) {
  System.out.println("Enter next var: ");
  vars[i] = dd.nextInt();

Or as Chip suggested, you can parse the input from one line:

Scanner in = new Scanner(;
int[] vars = new int[3];

System.out.println("Enter "+vars.length+" vars: ");
for(int i = 0; i < vars.length; i++)
  vars[i] = in.nextInt();

You were on the right track, and what you did works. This is just a nicer and more flexible way of doing things.

Programmatically add custom event in the iPhone Calendar

Remember to set the endDate to the created event, it is mandatory.

Otherwise it will fail (almost silently) with this error:

"Error Domain=EKErrorDomain Code=3 "No end date has been set." UserInfo={NSLocalizedDescription=No end date has been set.}"

The complete working code for me is:

EKEventStore *store = [EKEventStore new];
[store requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error) {
    if (!granted) { return; }
    EKEvent *calendarEvent = [EKEvent eventWithEventStore:store];
    calendarEvent.title = [NSString stringWithFormat:@"CEmprendedor: %@",];
    calendarEvent.startDate =;
    // 5 hours of duration, we must add the duration of the event to the API
    NSDate *endDate = [ dateByAddingTimeInterval:60*60*5];
    calendarEvent.endDate = endDate;
    calendarEvent.calendar = [store defaultCalendarForNewEvents];
    NSError *err = nil;
    [store saveEvent:calendarEvent span:EKSpanThisEvent commit:YES error:&err];
    self.savedEventId = calendarEvent.eventIdentifier;  //saving the calendar event id to possibly deleted them

What is the best/safest way to reinstall Homebrew?

For Mac OS X Mojave and above

To Uninstall Homebrew, run following command:

sudo ruby -e "$(curl -fsSL"

To Install Homebrew, run following command:

ruby -e "$(curl -fsSL"

And if you run into Permission denied issue, try running this command followed by install command again:

sudo chown -R $(whoami):admin /usr/local/* && sudo chmod -R g+rwx /usr/local/*

How to get the scroll bar with CSS overflow on iOS

Solution given by Chris Barr here

function isTouchDevice(){
        return true;
        return false;

function touchScroll(id){
    if(isTouchDevice()){ //if touch events exist...
        var el=document.getElementById(id);
        var scrollStartPos=0;

        document.getElementById(id).addEventListener("touchstart", function(event) {

        document.getElementById(id).addEventListener("touchmove", function(event) {

Works fine for me. Remove event.preventDefault if you need to use some clicks...

Using grep to search for a string that has a dot in it

There are so many answers here suggesting to escape the dot with \. but I have been running into this issue over and over again: \. gives me the same result as .

However, these two expressions work for me:

$ grep -r 0\\.49 *


$ grep -r 0[.]49 *

I'm using a "normal" bash shell on Ubuntu and Archlinux.

Edit, or, according to comments:

$ grep -r '0\.49' *

Note, the single-quotes doing the difference here.

Remove secure warnings (_CRT_SECURE_NO_WARNINGS) from projects by default in Visual Studio

If your project does not use stdafx.h, you can put the following lines as the first lines in your .cpp file and the compiler warning should go away -- at least it did for me in Visual Studio C++ 2008.


It's ok to have comment and blank lines before them.

How to scale a UIImageView proportionally?

Here is how you can scale it easily.

This works in 2.x with the Simulator and the iPhone.

UIImage *thumbnail = [originalImage _imageScaledToSize:CGSizeMake(40.0, 40.0) interpolationQuality:1];

Creating C formatted strings (not printing them)

If you have a POSIX-2008 compliant system (any modern Linux), you can use the safe and convenient asprintf() function: It will malloc() enough memory for you, you don't need to worry about the maximum string size. Use it like this:

char* string;
if(0 > asprintf(&string, "Formatting a number: %d\n", 42)) return error;

This is the minimum effort you can get to construct the string in a secure fashion. The sprintf() code you gave in the question is deeply flawed:

  • There is no allocated memory behind the pointer. You are writing the string to a random location in memory!

  • Even if you had written

    char s[42];

    you would be in deep trouble, because you can't know what number to put into the brackets.

  • Even if you had used the "safe" variant snprintf(), you would still run the danger that your strings gets truncated. When writing to a log file, that is a relatively minor concern, but it has the potential to cut off precisely the information that would have been useful. Also, it'll cut off the trailing endline character, gluing the next log line to the end of your unsuccessfully written line.

  • If you try to use a combination of malloc() and snprintf() to produce correct behavior in all cases, you end up with roughly twice as much code than I have given for asprintf(), and basically reprogram the functionality of asprintf().

If you are looking at providing a wrapper of log_out() that can take a printf() style parameter list itself, you can use the variant vasprintf() which takes a va_list as an argument. Here is a perfectly safe implementation of such a wrapper:

//Tell gcc that we are defining a printf-style function so that it can do type checking.
//Obviously, this should go into a header.
void log_out_wrapper(const char *format, ...) __attribute__ ((format (printf, 1, 2)));

void log_out_wrapper(const char *format, ...) {
    char* string;
    va_list args;

    va_start(args, format);
    if(0 > vasprintf(&string, format, args)) string = NULL;    //this is for logging, so failed allocation is not fatal

    if(string) {
    } else {
        log_out("Error while logging a message: Memory allocation failed.\n");

How can I find the number of elements in an array?

int main()
    int arr[]={10,20,30,40,50,60};
    int *p;
    int count=0;


    printf("The no of elements in array=%d",count);

    return 0;



p is a pointer to a 1-D array, and in the loop for(p=arr,p<&arr+1;p++) I made p point to the base address. Suppose its base address is 1000; if we increment p then it points to 1002 and so on. Now coming to the concept of &arr - It basically represents the whole array, and if we add 1 to the whole array i.e. &arr+1, it gives the address 1012 i.e. the address of next 1-D array (in our case the size of int is 2), so the condition becomes 1000<1012.

So, basically the condition becomes


And now let's check the condition and count the value

  • 1st time p=1000 and p<1012 condition is true: enter in the loop, increment the value of count to 1.
  • 2nd time p=1002 and p<1012 condition is true: enter in the loop, increment the value of count to 2.
  • ...
  • 6th time p=1010 and p<1012 condition is true: enter in the loop, increment the value of count to 6.
  • Last time p=1012 and p<1012 condition is false: print the value of count=6 in printf statement.

check if file exists in php

if (!file_exists('')) {   
$filefound = '0';

Select the first 10 rows - Laravel Eloquent

The simplest way in laravel 5 is:


return view('',compact('listings'));

Generate a dummy-variable

Hi i wrote this general function to generate a dummy variable which essentially replicates the replace function in Stata.

If x is the data frame is x and i want a dummy variable called a which will take value 1 when x$b takes value c

  for(i in 1:n){

Cannot connect to local SQL Server with Management Studio

Check the sql log in the LOG directory of your instance - see if anything is going on there. You'll need to stop the service to open the log - or restart and you can read the old one - named with .1 on the end.

With the error you're getting, you need to enable TCP/IP or Named pipes for named connections. Shared memory connection should work, but you seem to not be using that. Are you trying to connect through SSMS?

In my log I see entries like this...

Server local connection provider is ready to accept connection on [\\.\pipe\mssql$sqlexpress\sql\query ]

As the comments said, .\SQLEXPRESS should work. Also worstationName\SQLEXPRESS will work.

npm - "Can't find Python executable "python", you can set the PYTHON env variable."

You got to add python to your PATH variable. One thing you can do is Edit your Path variable now and add


Your variable PYTHON should point to the root directory of your python installation.

Executing an EXE file using a PowerShell script

In the Powershell, cd to the .exe file location. For example:

cd C:\Users\Administrators\Downloads

PS C:\Users\Administrators\Downloads> & '.\aaa.exe'

The installer pops up and follow the instruction on the screen.

How to check if a char is equal to an empty space?

To compare Strings you have to use the equals keyword.


Elegant ways to support equivalence ("equality") in Python classes

You don't have to override both __eq__ and __ne__ you can override only __cmp__ but this will make an implication on the result of ==, !==, < , > and so on.

is tests for object identity. This means a is b will be True in the case when a and b both hold the reference to the same object. In python you always hold a reference to an object in a variable not the actual object, so essentially for a is b to be true the objects in them should be located in the same memory location. How and most importantly why would you go about overriding this behaviour?

Edit: I didn't know __cmp__ was removed from python 3 so avoid it.

get the value of input type file , and alert if empty

<script type="text/javascript">
$(document).ready(function() {
        var imgVal = $('#uploadImage').val(); 
            alert("empty input file"); 

        return false; 


<input type="file" name="image" id="uploadImage" size="30" /> 
<input type="submit" name="upload" id="upload"  class="send_upload" value="upload" /> 

setImmediate vs. nextTick

Use setImmediate if you want to queue the function behind whatever I/O event callbacks that are already in the event queue. Use process.nextTick to effectively queue the function at the head of the event queue so that it executes immediately after the current function completes.

So in a case where you're trying to break up a long running, CPU-bound job using recursion, you would now want to use setImmediate rather than process.nextTick to queue the next iteration as otherwise any I/O event callbacks wouldn't get the chance to run between iterations.

Construct pandas DataFrame from list of tuples of (row,col,values)

You can pivot your DataFrame after creating:

>>> df = pd.DataFrame(data)
>>> df.pivot(index=0, columns=1, values=2)
# avg DataFrame
1      c1     c2
r1  avg11  avg12
r2  avg21  avg22
>>> df.pivot(index=0, columns=1, values=3)
# stdev DataFrame
1        c1       c2
r1  stdev11  stdev12
r2  stdev21  stdev22

APT command line interface-like yes/no input?

One-liner with Python 3.8 and above:

while res:= input("When correct, press enter to continue...").lower() not in {'y','yes','Y','YES',''}: pass

How do I check if an HTML element is empty using jQuery?

I found this to be the only reliable way (since Chrome & FF consider whitespaces and linebreaks as elements):


How to see the CREATE VIEW code for a view in PostgreSQL?

If you want an ANSI SQL-92 version:

select view_definition from information_schema.views where table_name = 'view_name';

Regular expression for first and last name

A simple function using preg_match in php

function name_validation($name) {
    if (!preg_match("/^[a-zA-Z ]*$/", $name) === false) {
        echo "$name is a valid name";
    } else {
        echo "$name is not a valid name";


How to make a div with no content have a width?

Use CSS to add a zero-width-space to your div. The content of the div will take no room but will force the div to display

   content: "\200B";

Access files stored on Amazon S3 through web browser

I found this related question: Directory Listing in S3 Static Website

As it turns out, if you enable public read for the whole bucket, S3 can serve directory listings. Problem is they are in XML instead of HTML, so not very user-friendly.

There are three ways you could go for generating listings:

  • Generate index.html files for each directory on your own computer, upload them to s3, and update them whenever you add new files to a directory. Very low-tech. Since you're saying you're uploading build files straight from Travis, this may not be that practical since it would require doing extra work there.

  • Use a client-side S3 browser tool.

  • Use a server-side browser tool.

    • s3browser (PHP)
    • s3index Scala. Going by the existence of a Procfile, it may be readily deployable to Heroku. Not sure since I don't have any experience with Scala.

PHP order array by date?

You don't need to convert your dates to timestamp before the sorting, but it's a good idea though because it will take more time to sort without it.

$data = array(
        "title" => "Another title",
        "date"  => "Fri, 17 Jun 2011 08:55:57 +0200"
        "title" => "My title",
        "date"  => "Mon, 16 Jun 2010 06:55:57 +0200"

function sortFunction( $a, $b ) {
    return strtotime($a["date"]) - strtotime($b["date"]);
usort($data, "sortFunction");

Error Message : Cannot find or open the PDB file

If this happens in visual studio then clean your project and run it again.

Build --> Clean Solution

Run (or F5)

From Now() to Current_timestamp in Postgresql

Here is an example ...

select * from tablename where to_char(added_time, 'YYYY-MM-DD')  = to_char( now(), 'YYYY-MM-DD' )

added_time is a column name which I converted to char for match

Difference between "enqueue" and "dequeue"

Enqueue means to add an element, dequeue to remove an element.

var stackInput= []; // First stack
var stackOutput= []; // Second stack

// For enqueue, just push the item into the first stack
function enqueue(stackInput, item) {
  return stackInput.push(item);

function dequeue(stackInput, stackOutput) {
  // Reverse the stack such that the first element of the output stack is the
  // last element of the input stack. After that, pop the top of the output to
  // get the first element that was ever pushed into the input stack
  if (stackOutput.length <= 0) {
    while(stackInput.length > 0) {
      var elementToOutput = stackInput.pop();

  return stackOutput.pop();

How do I enumerate through a JObject?

For people like me, linq addicts, and based on svick's answer, here a linq approach:

using System.Linq;
//make it linq iterable. 
var obj_linq = Response.Cast<KeyValuePair<string, JToken>>();

Now you can make linq expressions like:

JToken x = obj_linq
          .Where( d => d.Key == "my_key")
          .Select(v => v)
string y = ((JValue)x).Value;

Or just:

var y = obj_linq
       .Where(d => d.Key == "my_key")
       .Select(v => ((JValue)v.Value).Value)

Or this one to iterate over all data:

obj_linq.ToList().ForEach( x => { do stuff } ); 

Get int from String, also containing letters, in Java

Replace all non-digit with blank: the remaining string contains only digits.

Integer.parseInt(s.replaceAll("[\\D]", ""))

This will also remove non-digits inbetween digits, so "x1x1x" becomes 11.

If you need to confirm that the string consists of a sequence of digits (at least one) possibly followed a letter, then use this:


How do I get countifs to select all non-blank cells in Excel?

If you are using multiple criteria, and want to count the number of non-blank cells in a particular column, you probably want to look at DCOUNTA.


  A   B   C   D  E   F   G
1 Dog Cat Cow    Dog Cat
2 x   1          x   1
3 x   2 
4 x   1   nb     Result:
5 x   2   nb     1

Formula in E5: =DCOUNTA(A1:C5,"Cow",E1:F2)

How can I play sound in Java?

I'm surprised nobody suggested using Applet. Use Applet. You'll have to supply the beep audio file as a wav file, but it works. I tried this on Ubuntu:

package javaapplication2;

import java.applet.Applet;
import java.applet.AudioClip;

public class JavaApplication2 {

    public static void main(String[] args) throws MalformedURLException {
        File file = new File("/path/to/your/sounds/beep3.wav");
        URL url = null;
        if (file.canRead()) {url = file.toURI().toURL();}
        AudioClip clip = Applet.newAudioClip(url);;
        System.out.println("should've played by now");
//beep3.wav was available from:

plot is not defined

If you want to use a function form a package or module in python you have to import and reference them. For example normally you do the following to draw 5 points( [1,5],[2,4],[3,3],[4,2],[5,1]) in the space:

import matplotlib.pyplot

In your solution

from matplotlib import*

This imports the package matplotlib and "plot is not defined" means there is no plot function in matplotlib you can access directly, but instead if you import as

from matplotlib.pyplot import *

Now you can use any function in matplotlib.pyplot without referencing them with matplotlib.pyplot.

I would recommend you to name imports you have, in this case you can prevent disambiguation and future problems with the same function names. The last and clean version of above example looks like:

import matplotlib.pyplot as plt

reactjs - how to set inline style of backgroundcolor?

If you want more than one style this is the correct full answer. This is div with class and style:

<div className="class-example" style={{width: '300px', height: '150px'}}></div>

What are the advantages and disadvantages of recursion?

Any algorithm implemented using recursion can also be implemented using iteration.

Why not to use recursion

  1. It is usually slower due to the overhead of maintaining the stack.
  2. It usually uses more memory for the stack.

Why to use recursion

  1. Recursion adds clarity and (sometimes) reduces the time needed to write and debug code (but doesn't necessarily reduce space requirements or speed of execution).
  2. Reduces time complexity.
  3. Performs better in solving problems based on tree structures.

For example, the Tower of Hanoi problem is more easily solved using recursion as opposed to iteration.

How to comment multiple lines in Visual Studio Code?

Win10 with French / English Keyboard CTRL + / , ctrl+k+u and ctrl+k+l don't work.

Here's how it works:

/* */ SHIFT + ALT + A

// CTRL + É

É key is next to right Shift.

What is the ideal data type to use when storing latitude / longitude in a MySQL database?

No need to go far, according to Google Maps, the best is FLOAT(10,6) for lat and lng.

How to get base URL in Web API controller?

Al WebApi 2, just calling HttpContext.Current.Request.Path;

Get selected option text with JavaScript

Try options

function myNewFunction(sel) {_x000D_
<select id="box1" onChange="myNewFunction(this);">_x000D_
  <option value="98">dog</option>_x000D_
  <option value="7122">cat</option>_x000D_
  <option value="142">bird</option>_x000D_

Checking whether a string starts with XXXX

RanRag has already answered it for your specific question.

However, more generally, what you are doing with

if [[ "$string" =~ ^hello ]]

is a regex match. To do the same in Python, you would do:

import re
if re.match(r'^hello', somestring):
    # do stuff

Obviously, in this case, somestring.startswith('hello') is better.

Setting focus to a textbox control

Using Focus method

  Private Sub frmTest_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    End Sub

How do you calculate log base 2 in Java for integers?

Why not:

public static double log2(int n)
    return (Math.log(n) / Math.log(2));

builtins.TypeError: must be str, not bytes

The outfile should be in binary mode.

outFile = open('output.xml', 'wb')

Aligning textviews on the left and right edges in Android layout

enter image description here

This Code will Divide the control into two equal sides.

        android:text = "Left Side"
        android:layout_weight = "1"
        android:id = "@+id/txtLeft"/>

    <TextView android:text = "Right Side"
        android:layout_weight = "1"
        android:id = "@+id/txtRight"/>

Is there a way to rollback my last push to Git?

First you need to determine the revision ID of the last known commit. You can use HEAD^ or HEAD~{1} if you know you need to reverse exactly one commit.

git reset --hard <revision_id_of_last_known_good_commit>
git push --force

SQL Server 2008: TOP 10 and distinct together

well I wouldn't have expected it, but Halim's SELECT distinct TOP 10 MyId FROM sometable

is functionally identical to Vaishnavi Kumar's select top 10 from(select distinct from tablename)tablename

create table #names ([name] varchar(10))
insert into #names ([name]) values ('jim')
insert into #names ([name]) values ('jim')
insert into #names ([name]) values ('bob')
insert into #names ([name]) values ('mary')
insert into #names ([name]) values ('bob')
insert into #names ([name]) values ('mary')
insert into #names ([name]) values ('john')
insert into #names ([name]) values ('mark')
insert into #names ([name]) values ('matthew')
insert into #names ([name]) values ('luke')
insert into #names ([name]) values ('peter')

select distinct top 5 [name] from #names

select top 5 * from (select distinct [name] from #names) subquery 

drop table #names

produces the same results for both selects:

1   bob
2   jim
3   john
4   luke
5   mark

it's curious that select top 5 distinct is not valid, but select distinct top 5 is and works as you might expect select top 5 distinct to work.

How do I debug Node.js applications?

Assuming you have node-inspector installed on your computer (if not, just type 'npm install -g node-inspector') you just have to run:

node-inspector & node --debug-brk scriptFileName.js

And paste the URI from the command line into a WebKit (Chrome / Safari) browser.

fetch from origin with deleted remote branches?

This worked for me.

git remote update --prune

'pip install' fails for every package ("Could not find a version that satisfies the requirement")

Upgrade pip as follows:

curl | python

Note: You may need to use sudo python above if not in a virtual environment.

What's happening: sites are stopping support for TLS versions 1.0 and 1.1. This means that Mac OS X version 10.12 (Sierra) or older will not be able to use pip unless they upgrade pip as above.

(Note that upgrading pip via pip install --upgrade pip will also not upgrade it correctly. It is a chicken-and-egg issue)

This thread explains it (thanks to this Twitter post):

Mac users who use pip and PyPI:

If you are running macOS/OS X version 10.12 or older, then you ought to upgrade to the latest pip (9.0.3) to connect to the Python Package Index securely:

curl | python

and we recommend you do that by April 8th.

Pip 9.0.3 supports TLSv1.2 when running under system Python on macOS < 10.13. Official release notes:

Also, the Python status page:

Completed - The rolling brownouts are finished, and TLSv1.0 and TLSv1.1 have been disabled. Apr 11, 15:37 UTC

Update - The rolling brownouts have been upgraded to a blackout, TLSv1.0 and TLSv1.1 will be rejected with a HTTP 403 at all times. Apr 8, 15:49 UTC

Lastly, to avoid other install errors, make sure you also upgrade setuptools after doing the above:

pip install --upgrade setuptools

Unable to establish SSL connection upon wget on Ubuntu 14.04 LTS

If you trust the host, either add the valid certificate, specify --no-check-certificate or add:

check_certificate = off

into your ~/.wgetrc.

In some rare cases, your system time could be out-of-sync therefore invalidating the certificates.


Have you verified that there is in fact a row where Staff_Id = @PersonID? What you've posted works fine in a test script, assuming the row exists. If you comment out the insert statement, then the error is raised.

set nocount on

create table Timesheet_Hours (Staff_Id int, BookedHours int, Posted_Flag bit)

insert into Timesheet_Hours (Staff_Id, BookedHours, Posted_Flag) values (1, 5.5, 0)

declare @PersonID int
set @PersonID = 1

    SELECT 1    
    FROM Timesheet_Hours    
    WHERE Posted_Flag = 1    
        AND Staff_Id = @PersonID    
        RAISERROR('Timesheets have already been posted!', 16, 1)
        SELECT 1
        FROM Timesheet_Hours
        WHERE Staff_Id = @PersonID
            RAISERROR('Default list has not been loaded!', 16, 1)
            ROLLBACK TRAN
        print 'No problems here'

drop table Timesheet_Hours

How to import data from one sheet to another

Saw this thread while looking for something else and I know it is super old, but I wanted to add my 2 cents.

NEVER USE VLOOKUP. It's one of the worst performing formulas in excel. Use index match instead. It even works without sorting data, unless you have a -1 or 1 in the end of the match formula (explained more below)

Here is a link with the appropriate formulas.

The Sheet 2 formula would be this: =IF(A2="","",INDEX(Sheet1!B:B,MATCH($A2,Sheet1!$A:$A,0)))

  • IF(A2="","", means if A2 is blank, return a blank value
  • INDEX(Sheet1!B:B, is saying INDEX B:B where B:B is the data you want to return. IE the name column.
  • Match(A2, is saying to Match A2 which is the ID you want to return the Name for.
  • Sheet1!A:A, is saying you want to match A2 to the ID column in the previous sheet
  • ,0)) is specifying you want an exact value. 0 means return an exact match to A2, -1 means return smallest value greater than or equal to A2, 1 means return the largest value that is less than or equal to A2. Keep in mind -1 and 1 have to be sorted.

More information on the Index/Match formula

Other fun facts: $ means absolute in a formula. So if you specify $B$1 when filling a formula down or over keeps that same value. If you over $B1, the B remains the same across the formula, but if you fill down, the 1 increases with the row count. Likewise, if you used B$1, filling to the right will increment the B, but keep the reference of row 1.

I also included the use of indirect in the second section. What indirect does is allow you to use the text of another cell in a formula. Since I created a named range sheet1!A:A = ID, sheet1!B:B = Name, and sheet1!C:C=Price, I can use the column name to have the exact same formula, but it uses the column heading to change the search criteria.

Good luck! Hope this helps.

How do I escape a percentage sign in T-SQL?

WHERE column_name LIKE '%save 50[%] off!%'

Reading a string with spaces with sscanf

You want the %c conversion specifier, which just reads a sequence of characters without special handling for whitespace.

Note that you need to fill the buffer with zeroes first, because the %c specifier doesn't write a nul-terminator. You also need to specify the number of characters to read (otherwise it defaults to only 1):

memset(buffer, 0, 200);
sscanf("19 cool kid", "%d %199c", &age, buffer);

What does the colon (:) operator do?

Just to add, when used in a for-each loop, the ":" can basically be read as "in".


for (String name : names) {
    // remainder omitted

should be read "For each name IN names do ..."

what does "dead beef" mean?

It is also used for debugging purposes.

Here is a handy list of some of these values:

Add a pipe separator after items in an unordered list unless that item is the last on a line

Use :after pseudo selector. Look


ul li { float: left; }
ul li:after { content: "|"; padding: 0 .5em; }


jQuery solution:


    <ul id="animals">


div { width: 300px; }
ul li { float: left; border-right: 1px solid black; padding: 0 .5em; }
ul li:last-child { border: 0; }


var maxWidth = 300, // Your div max-width
    totalWidth = 0;
$('#animals li').each(function(){
    var currentWidth = $(this).outerWidth(),
        nextWidth = $(this).next().outerWidth();
    totalWidth += currentWidth;
    if ( (totalWidth + nextWidth) > maxWidth ) {
        $(this).css('border', 'none');
        totalWidth = 0;

Take a look here. I also added a few more animals.

What does the function then() mean in JavaScript?

Another example:

new Promise(function(ok) {
      /* myFunc1(param1, param2, ..) */
     /* myFunc1 succeed */
     /* Launch something else */
     /* console.log(whateverparam1) */
     /* myFunc2(whateverparam1, otherparam, ..) */
     /* myFunc2 succeed */
     /* Launch something else */
     /* myFunc3(whatever38, ..) */

The same logic using arrow functions shorthand.

?? This can cause issues with multiple calls see comments!

The syntax of the first snippet using plain function is preferable here.

new Promise((ok) =>
      /* myFunc1(param1, param2, ..) */
)).then(() =>
     /* myFunc1 succeed */
     /* Launch something else */
     /* Only ONE call or statment can be made inside arrow functions */
     /* For example, using console.log here will break everything */
     /* myFunc2(whateverparam1, otherparam, ..) */
).then(() =>
     /* myFunc2 succeed */
     /* Launch something else */
     /* Only ONE call or statment can be made inside arrow functions */
     /* For example, using console.log here will break everything */
     /* myFunc3(whatever38, ..) */

Parameter in like clause JPQL

You could use the JPA LOCATE function.

LOCATE(searchString, candidateString [, startIndex]): Returns the first index of searchString in candidateString. Positions are 1-based. If the string is not found, returns 0.

FYI: The documentation on my top google hit had the parameters reversed.

  entity e
  (0 < LOCATE(:searchStr,

How to avoid Sql Query Timeout

Although there is clearly some kind of network instability or something interfering with your connection (15 minutes is possible that you could be crossing a NAT boundary or something in your network is dropping the session), I would think you want such a simple?) query to return well within any anticipated timeoue (like 1s).

I would talk to your DBA and get an index created on the underlying tables on MemberType, Status. If there isn't a single underlying table or these are more complex and created by the view or UDF, and you are running SQL Server 2005 or above, have him consider indexing the view (basically materializing the view in an indexed fashion).

Mongoose: CastError: Cast to ObjectId failed for value "[object Object]" at path "_id"

I was receiving this error CastError: Cast to ObjectId failed for value “[object Object]” at path “_id” after creating a schema, then modifying it and couldn't track it down. I deleted all the documents in the collection and I could add 1 object but not a second. I ended up deleting the collection in Mongo and that worked as Mongoose recreated the collection.

Facebook api: (#4) Application request limit reached

The Facebook API limit isn't really documented, but apparently it's something like: 600 calls per 600 seconds, per token & per IP. As the site is restricted, quoting the relevant part:

After some testing and discussion with the Facebook platform team, there is no official limit I'm aware of or can find in the documentation. However, I've found 600 calls per 600 seconds, per token & per IP to be about where they stop you. I've also seen some application based rate limiting but don't have any numbers.

As a general rule, one call per second should not get rate limited. On the surface this seems very restrictive but remember you can batch certain calls and use the subscription API to get changes.

As you can access the Graph API on the client side via the Javascript SDK; I think if you travel your request for photos from the client, you won't hit any application limit as it's the user (each one with unique id) who's fetching data, not your application server (unique ID).

This may mean a huge refactor if everything you do go through a server. But it seems like the best solution if you have so many request (as it'll give a breath to your server).

Else, you can try batch request, but I guess you're already going this way if you have big traffic.

If nothing of this works, according to the Facebook Platform Policy you should contact them.

If you exceed, or plan to exceed, any of the following thresholds please contact us as you may be subject to additional terms: (>5M MAU) or (>100M API calls per day) or (>50M impressions per day).

What is the difference between function and procedure in PL/SQL?

In the few words - function returns something. You can use function in SQL query. Procedure is part of code to do something with data but you can not invoke procedure from query, you have to run it in PL/SQL block.

How to add a new schema to sql server 2008?

Here's a trick to easily check if the schema already exists, and then create it, in it's own batch, to avoid the error message of trying to create a schema when it's not the only command in a batch.

IF NOT EXISTS (SELECT schema_name 
    FROM information_schema.schemata 
    WHERE schema_name = 'newSchemaName' )
    EXEC sp_executesql N'CREATE SCHEMA NewSchemaName;';

How to make readonly all inputs in some div in Angular2?

If using reactive forms, you can also disable the entire form or any sub-set of controls in a FormGroup with myFormGroup.disable().

How to install a specific JDK on Mac OS X?

As of Mac OS X v10.6 (Snow Leopard), you can run Java 6 in 32-bit mode on either 32-bit or 64-bit Intel processor equipped Macs.

If you cannot upgrade to Snow Leopard, Soy Latte is a pre-compiled version of Java 6 for Intel 32-bit.

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

The following Javascript snippet works in Chrome by using the new 'download' attribute of links and simulating a click.

function downloadWithName(uri, name) {
  var link = document.createElement("a"); = name;
  link.href = uri;;

And the following example shows it's use:

downloadWithName("data:,Hello%2C%20World!", "helloWorld.txt")

Use Ant for running program with command line arguments

What I did in the end is make a batch file to extract the CLASSPATH from the ant file, then run java directly using this:

In my build.xml:

<target name="printclasspath">
    <pathconvert property="classpathProp" refid="project.class.path"/>

In another script called '':

export CLASSPATH=$(ant -q printclasspath | grep echo | cut -d \  -f 7):build
java "$@"

It's no longer cross-platform, but at least it's relatively easy to use, and one could provide a .bat file that does the same as the It's a very short batch script. It's not like migrating the entire build to platform-specific batch files.

I think it's a shame there's not some option in ant whereby you could do something like:

ant -- arg1 arg2 arg3

mpirun uses this type of syntax; ssh also can use this syntax I think.

Predicate Delegates in C#

Leading on from Andrew's answer with regards to c#2 and c#3 ... you can also do them inline for a one off search function (see below).

using System;
using System.Collections.Generic;

class Program
    static void Main()
        List<int> list = new List<int> { 1, 2, 3 };

        List<int> newList = list.FindAll(delegate(int arg)
                               return arg> 2;

Hope this helps.

$(document).ready equivalent without jQuery

The setTimeout/setInterval solutions presented here will only work in specific circumstances.

The problem shows up especially in older Internet Explorer versions up to 8.

The variables affecting the success of these setTimeout/setInterval solutions are:

1) dynamic or static HTML
2) cached or non cached requests
3) size of the complete HTML document
4) chunked or non chunked transfer encoding

the original (native Javascript) code solving this specific issue is here: (test)

this is the code from which the jQuery team have built their implementation.

ISO C++ forbids comparison between pointer and integer [-fpermissive]| [c++]

char a[2] defines an array of char's. a is a pointer to the memory at the beginning of the array and using == won't actually compare the contents of a with 'ab' because they aren't actually the same types, 'ab' is integer type. Also 'ab' should be "ab" otherwise you'll have problems here too. To compare arrays of char you'd want to use strcmp.

Something that might be illustrative is looking at the typeid of 'ab':

#include <iostream>
#include <typeinfo>
using namespace std;
int main(){
    int some_int =5;
    std::cout << typeid('ab').name() << std::endl;
    std::cout << typeid(some_int).name() << std::endl;
    return 0;

on my system this returns:


showing that 'ab' is actually evaluated as an int.

If you were to do the same thing with a std::string then you would be dealing with a class and std::string has operator == overloaded and will do a comparison check when called this way.

If you wish to compare the input with the string "ab" in an idiomatic c++ way I suggest you do it like so:

#include <iostream>
#include <string>
using namespace std;
int main(){
    string a;
    cout<<"enter ab ";
    return 0;

This one is due to:

if(a=='ab') , here, a is const char* type (ie : array of char)

'ab' is a constant value,which isn't evaluated as string (because of single quote) but will be evaluated as integer.

Since char is a primitive type inherited from C, no operator == is defined.

the good code should be:

if(strcmp(a,"ab")==0) , then you'll compare a const char* to another const char* using strcmp.

check all socket opened in linux OS

/proc/net/tcp -a list of open tcp sockets

/proc/net/udp -a list of open udp sockets

/proc/net/raw -a list all the 'raw' sockets

These are the files, use cat command to view them. For example:

cat /proc/net/tcp

You can also use the lsof command.

lsof is a command meaning "list open files", which is used in many Unix-like systems to report a list of all open files and the processes that opened them.

Can you change what a symlink points to after it is created?

Just in case it helps: there is a way to edit a symlink with midnight commander (mc). The menu command is (in French on my mc interface):

Fichier / Éditer le lien symbolique

which may be translated to:

File / Edit symbolic link

The shortcut is C-x C-s

Maybe it internally uses the ln --force command, I don't know.

Now, I'm trying to find a way to edit a whole lot of symlinks at once (that's how I arrived here).

How do I add FTP support to Eclipse?

Install Aptana plugin to your Eclipse installation.

It has built-in FTP support, and it works excellently.

You can:

  • Edit files directly from the FTP server
  • Perform file/folder management (copy, delete, move, rename, etc.)
  • Upload/download files to/from FTP server
  • Synchronize local files with FTP server. You can make several profiles (actually projects) for this so you won't have to reinput over and over again.

As a matter of fact the FTP support is so good I'm using Aptana (or Eclipse + Aptana) now for all my FTP needs. Plus I get syntax highlighting/whatever coding support there is. Granted, Eclipse is not the speediest app to launch, but it doesn't bug me so much.

How to remove the left part of a string?

Remove prefix from a string

# ...
if line.startswith(prefix):
   return line[len(prefix):]

Split on the first occurrence of the separator via str.partition()

def findvar(filename, varname="Path", sep="=") :
    for line in open(filename):
        if line.startswith(varname + sep):
           head, sep_, tail = line.partition(sep) # instead of `str.split()`
           assert head == varname
           assert sep_ == sep
           return tail

Parse INI-like file with ConfigParser

from ConfigParser import SafeConfigParser
config = SafeConfigParser() # requires section headers to be present

path = config.get(section, 'path', raw=1) # case-insensitive, no interpolation

Other options

C# error: Use of unassigned local variable

The compiler only knows that the code is or isn't reachable if you use "return". Think of Environment.Exit() as a function that you call, and the compiler don't know that it will close the application.

How to open a website when a Button is clicked in Android application?

You can wrap the buttons in anchors that href to the appropriate website.

<a href="">
  <input type="button" value="Button" />
<a href="">
  <input type="button" value="Button" />
<a href="">
  <input type="button" value="Button" />

When the user clicks the button (input) they are directed to the destination specified in the href property of the anchor.

Edit: Oops, I didn't read "Eclipse" in the question title. My mistake.

Nginx: Permission denied for nginx on Ubuntu

Make sure you are running the test as a superuser.

sudo nginx -t

Or the test wont have all the permissions needed to complete the test properly.

How can I control Chromedriver open window size?

#use chrome webdriver

driver = webdriver.Chrome('path to /chromedriver')

How to connect android wifi to adhoc wifi?

If you have a Microsoft Virtual WiFi Miniport Adapter as one of the available network adapters, you may do the following:

  • Run Windows Command Processor (cmd) as Administrator
  • Type: netsh wlan set hostednetwork mode=allow ssid=NAME key=PASSWORD
  • Then: netsh wlan start hostednetwork
  • Open "Control Panel\Network and Internet\Network Connections"
  • Right-click on your active network adapter (the one that you use to connect on the internet) and then click Properties
  • Then open Sharing tab
  • Check "Allow other network users to connect..." and select your WiFi Miniport Adapter
  • Once finished, type: netsh wlan stop hostednetwork

That's it!

Source: How to connect android phone to an ad-hoc network without softwares.

Convert JSONArray to String Array

The below code will convert the JSON array of the format


to List of String

[70.3.0;3, 6R_16B000I_J4;3, 46.3.0;3, 20.3.0;2, 4.1.3;0, 10.3.0;1]

Code :

ObjectMapper mapper = new ObjectMapper(); ArrayNode node = (ArrayNode)mapper.readTree(dataFromDb); data = node.findValuesAsText("version"); // "version" is the node in the JSON

and use com.fasterxml.jackson.databind.ObjectMapper

How to solve PHP error 'Notice: Array to string conversion in...'

$result = ob_get_clean();

if you want to capture the result in a variable

Pass array to MySQL stored routine

Use a join with a temporary table. You don't need to pass temporary tables to functions, they are global.

create temporary table ids( id int ) ;
insert into ids values (1),(2),(3) ;

delimiter //
drop procedure if exists tsel //
create procedure tsel() -- uses temporary table named ids. no params
  -- use the temporary table `ids` in the SELECT statement or
  -- whatever query you have
  select * from Users INNER JOIN ids on ;
END //

CALL tsel() ; -- call the procedure

Enabling the OpenSSL in XAMPP

Yes, you must open php.ini and remove the semicolon to:


If you don't have that line, check that you have the file (In my PC is on D:\xampp\php\ext) and add this to php.ini in the "Dynamic Extensions" section:


Things have changed for PHP > 7. This is what i had to do for PHP 7.2.

Step: 1: Uncomment extension=openssl

Step: 2: Uncomment extension_dir = "ext"

Step: 3: Restart xampp.


Explanation: ( From php.ini )

If you wish to have an extension loaded automatically, use the following syntax:


Note : The syntax used in previous PHP versions (extension=<ext>.so and extension='php_<ext>.dll) is supported for legacy reasons and may be deprecated in a future PHP major version. So, when it is possible, please move to the new (extension=<ext>) syntax.

Special Note: Be sure to appropriately set the extension_dir directive.

java.sql.SQLException: - ORA-01000: maximum open cursors exceeded

If your application is a Java EE application running on Oracle WebLogic as the application server, a possible cause for this issue is the Statement Cache Size setting in WebLogic.

If the Statement Cache Size setting for a particular data source is about equal to, or greater than, the Oracle database maximum open cursor count setting, then all of the open cursors can be consumed by cached SQL statements that are held open by WebLogic, resulting in the ORA-01000 error.

To address this, reduce the Statement Cache Size setting for each WebLogic datasource that points to the Oracle database to be significantly less than the maximum cursor count setting on the database.

In the WebLogic 10 Admin Console, the Statement Cache Size setting for each data source can be found at Services (left nav) > Data Sources > (individual data source) > Connection Pool tab.

Understanding lambda in python and using it to pass multiple arguments

I believe bind always tries to send an event parameter. Try:

self.entry_1.bind("<Return>", lambda event: self.calculate(self.buttonOut_1.grid_info(), 1))

You accept the parameter and never use it.

SELECT from nothing?

In Standard SQL, no. A WHERE clause implies a table expression.

From the SQL-92 spec:

7.6 "where clause"


Specify a table derived by the application of a "search condition" to the result of the preceding "from clause".

In turn:

7.4 "from clause"


Specify a table derived from one or more named tables.

A Standard way of doing it (i.e. should work on any SQL product):

SELECT DISTINCT 'Hello world' AS new_value
  FROM AnyTableWithOneOrMoreRows
 WHERE 1 = 1;

...assuming you want to change the WHERE clause to something more meaningful, otherwise it can be omitted.

Can you have a <span> within a <span>?

Yes. You can have a span within a span. Your problem stems from something else.

How much memory can a 32 bit process access on a 64 bit operating system?

An single 32-bit process under a 64-bit OS is limited to 2Gb. But if it is compiled to an EXE file with IMAGE_FILE_LARGE_ADDRESS_AWARE bit set, it then has a limit of 4 GB, not 2Gb - see

The things you hear about special boot flags, 3 GB, /3GB switches, or /userva are all about 32-bit operating systems and do not apply on 64-bit Windows.

See for more details.

As about the 32-bit operating systems, contrary to the belief, there is no physical limit of 4GB for 32-bit operating systems. For example, 32-bit Server Operating Systems like Microsoft Windows Server 2008 32-bit can access up to 64 GB (Windows Server 2008 Enterprise and Datacenter editions) – by means of Physical Address Extension (PAE), which was first introduced by Intel in the Pentium Pro, and later by AMD in the Athlon processor - it defines a page table hierarchy of three levels, with table entries of 64 bits each instead of 32, allowing these CPUs to directly access a physical address space larger than 4 gigabytes – so theoretically, a 32-bit OS can access 2^64 bytes theoretically, or 17,179,869,184 gigabytes, but the segment is limited by 4GB. However, due to marketing reasons, Microsoft have limited maximum accessible memory on non-server operating systems to just 4GB, or, even, 3GB effectively. Thus, a single process can access more than 4GB on a 32-bit OS - and Microsoft SQL server is an example.

32-bit processes under 64-bit Windows do not have any disadvantage comparing to 64-bit processes in using shared kernel's virtual address space (also called system space). All processes, be it 64-bit or 32-bit, under 64-bit Windows share the same 64-bit system space.

Given the fact that the system space is shared across all processes, on 32-bit Windows, processes that create large amount of handles (like threads, semaphores, files, etc.) consume system space by kernel objects and can run out of memory even if you have lot of memory available in total. In contrast, on 64-bit Windows, the kernel space is 64-bit and is not limited by 4 GB. All system calls made by 32-bit applications are converted to native 64-bit calls in the user mode.

SQL query with avg and group by

As I understand, you want the average value for each id at each pass. The solution is

SELECT id, pass, avg(value) FROM data_r1
GROUP BY id, pass;

@AspectJ pointcut for all methods of a class with specific annotation

Something like that:

@Before("execution(* com.yourpackage..*.*(..))")
public void monitor(JoinPoint jp) {
    if (jp.getTarget().getClass().isAnnotationPresent(Monitor.class)) {
       // perform the monitoring actions

Note that you must not have any other advice on the same class before this one, because the annotations will be lost after proxying.

Rails: How to run `rails generate scaffold` when the model already exists?

I had this challenge when working on a Rails 6 API application in Ubuntu 20.04.

I had already existing models, and I needed to generate corresponding controllers for the models and also add their allowed attributes in the controller params.

Here's how I did it:

I used the rails generate scaffold_controller to get it done.

I simply ran the following commands:

rails generate scaffold_controller School name:string logo:json motto:text address:text

rails generate scaffold_controller Program name:string logo:json school:references

This generated the corresponding controllers for the models and also added their allowed attributes in the controller params, including the foreign key attributes.

create  app/controllers/schools_controller.rb
invoke  test_unit
create    test/controllers/schools_controller_test.rb

create  app/controllers/programs_controller.rb
invoke  test_unit
create    test/controllers/programs_controller_test.rb

That's all.

I hope this helps

How do I create a slug in Django?

If you're using the admin interface to add new items of your model, you can set up a ModelAdmin in your and utilize prepopulated_fields to automate entering of a slug:

class ClientAdmin(admin.ModelAdmin):
    prepopulated_fields = {'slug': ('name',)}, ClientAdmin)

Here, when the user enters a value in the admin form for the name field, the slug will be automatically populated with the correct slugified name.

Change the default base url for axios

Instead of



this.$axios({ url: 'items', baseURL: '' })

If you don't pass method: 'XXX' then by default, it will send via get method.

Request Config:

How to pass an event object to a function in Javascript?

Although this is the accepted answer, toto_tico's answer below is better :)

Try making the onclick js use 'return' to ensure the desired return value gets used...

<button type="button" value="click me" onclick="return check_me();" />

Internal and external fragmentation

First of all the term fragmentation cues there's an entity divided into parts — fragments.

  • Internal fragmentation: Typical paper book is a collection of pages (text divided into pages). When a chapter's end isn't located at the end of page and new chapter starts from new page, there's a gap between those chapters and it's a waste of space — a chunk (page for a book) has unused space inside (internally) — "white space"

  • External fragmentation: Say you have a paper diary and you didn't write your thoughts sequentially page after page, but, rather randomly. You might end up with a situation when you'd want to write 3 pages in row, but you can't since there're no 3 clean pages one-by-one, you might have 15 clean pages in the diary totally, but they're not contiguous

Get git branch name in Jenkins Pipeline/Jenkinsfile

This is for simple Pipeline type - not multibranch. Using Jenkins 2.150.1

environment { FULL_PATH_BRANCH = "${sh(script:'git name-rev --name-only HEAD', returnStdout: true)}" GIT_BRANCH = FULL_PATH_BRANCH.substring(FULL_PATH_BRANCH.lastIndexOf('/') + 1, FULL_PATH_BRANCH.length()) }

then use it env.GIT_BRANCH

Is there a minlength validation attribute in HTML5?

See Some browsers may not support this attribute.

If the value of the "type" is one of them:

text, email, search, password, tel, or URL (warning: not include number | no browser support "tel" now - 2017.10)

Use the minlength(/ maxlength) attribute. It specifies the minimum number of characters.

For example,

<input type="text" minlength="11" maxlength="11" pattern="[0-9]*" placeholder="input your phone number">

Or use the "pattern" attribute:

<input type="text" pattern="[0-9]{11}" placeholder="input your phone number">

If the "type" is number, although minlength(/ maxlength) is not be supported, you can use the min(/ max) attribute instead of it.

For example,

<input type="number" min="100" max="999" placeholder="input a three-digit number">

What is the most efficient string concatenation method in python?

it pretty much depends on the relative sizes of the new string after every new concatenation. With the + operator, for every concatenation a new string is made. If the intermediary strings are relatively long, the + becomes increasingly slower because the new intermediary string is being stored.

Consider this case:

from time import time
#case 1
for i in range(1000):
print time()-t

#case 2
for i in xrange(1000):
print time()-t

#case 3
for i in range(1000):
print time()-t

#case 4
for i in xrange(1000):
print time()-t


1 0.00493192672729

2 0.000509023666382

3 0.00042200088501

4 0.000482797622681

In the case of 1&2, we add a large string, and join() performs about 10 times faster. In case 3&4, we add a small string, and '+' performs slightly faster

How can I truncate a double to only two decimal places in Java?

3.545555555 to get 3.54. Try Following for this:

    DecimalFormat df = new DecimalFormat("#.##");


    double result = new Double(df.format(3.545555555);

This will give= 3.54!

Why is my CSS bundling not working with a bin deployed MVC4 app?

I was facing this problem while deploying the code in Azure websites. it did worked when I deployed build from and wasn't when I tried to publish the build from visual studio 2013. the main problem was CSS Minification. I totally agree with 1st response to this question. but thought of sharing solution that worked for me, may be it will help you in fixing it.

basically when we deploy through VSO it generates minification files for css, js by kicking in system.web.Optimization, but when we do publish build from VS 2013 we have to take care of the below. bundling-and-minification 1. make sure the folder structure and your bundler naming convention should be different. something like this.

bundles.Add(new StyleBundle("~/Content/materialize/mcss").Include(

2. add at the bottom of your bundleconfig definition

public static void RegisterBundles(BundleCollection bundles)
  bundles.Add(new ScriptBundle("~/bundles/jquery").Include(

   // Code removed for clarity.
   BundleTable.EnableOptimizations = true;

3. make sure to add debug false in web.config (when you start local debuging VS2013 will give you a popup saying that you need to make sure to putting it back before deploying into prod. that itself explains much.

  <compilation debug="true" />
  <!-- Lines removed for clarity. -->

jQuery hide and show toggle div with plus and minus icon

Here is a quick edit of Enve's answer. I do like roXor's solution, but background images are not necessary. And everbody seems to forgot a preventDefault as well.

$(document).ready(function() {_x000D_
  $('.show_hide').click(function(e) {_x000D_
    var val = $(this).text() == "-" ? "+" : "-";_x000D_
<script src=""></script>_x000D_
<a href="#" class="show_hide">+</a>_x000D_
<div class="slidingDiv">_x000D_
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer nec odio. Praesent libero. Sed cursus ante dapibus diam. Sed nisi. Nulla quis sem at nibh elementum imperdiet. Duis sagittis ipsum. Praesent mauris. Fusce nec tellus sed augue semper porta._x000D_
    Mauris massa. Vestibulum lacinia arcu eget nulla. </p>_x000D_
  <p>Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Curabitur sodales ligula in libero. Sed dignissim lacinia nunc. Curabitur tortor. Pellentesque nibh. Aenean quam. In scelerisque sem at dolor. Maecenas mattis._x000D_
    Sed convallis tristique sem. Proin ut ligula vel nunc egestas porttitor. Morbi lectus risus, iaculis vel, suscipit quis, luctus non, massa. Fusce ac turpis quis ligula lacinia aliquet. Mauris ipsum. </p>_x000D_

How to use IntelliJ IDEA to find all unused code?

After you've run the Inspect by Name, select all the locations, and make use of the Apply quick fixes to all the problems drop-down, and use either (or both) of Delete unused parameter(s) and Safe Delete.

Don't forget to hit Do Refactor afterwards.

Then you'll need to run another analysis, as the refactored code will no doubt reveal more unused declarations.

Apply quick fixes to all the problems

Select folder dialog WPF

Based on Oyun's answer, it's better to use a dependency property for the FolderName. This allows (for example) binding to sub-properties, which doesn't work in the original. Also, in my adjusted version, the dialog shows selects the initial folder.

Usage in XAML:

<Button Content="...">
      <Behavior:FolderDialogBehavior FolderName="{Binding FolderPathPropertyName, Mode=TwoWay}"/>


using System.Windows;
using System.Windows.Forms;
using System.Windows.Interactivity;
using Button = System.Windows.Controls.Button;

public class FolderDialogBehavior : Behavior<Button>
    #region Attached Behavior wiring
    protected override void OnAttached()
        AssociatedObject.Click += OnClick;

    protected override void OnDetaching()
        AssociatedObject.Click -= OnClick;

    #region FolderName Dependency Property
    public static readonly DependencyProperty FolderName =
            typeof(string), typeof(FolderDialogBehavior));

    public static string GetFolderName(DependencyObject obj)
        return (string)obj.GetValue(FolderName);

    public static void SetFolderName(DependencyObject obj, string value)
        obj.SetValue(FolderName, value);

    private void OnClick(object sender, RoutedEventArgs e)
        var dialog = new FolderBrowserDialog();
        var currentPath = GetValue(FolderName) as string;
        dialog.SelectedPath = currentPath;
        var result = dialog.ShowDialog();
        if (result == DialogResult.OK)
            SetValue(FolderName, dialog.SelectedPath);

Getting file size in Python?

Use os.path.getsize(path) which will

Return the size, in bytes, of path. Raise OSError if the file does not exist or is inaccessible.

import os

Or use os.stat(path).st_size

import os

Or use Path(path).stat().st_size (Python 3.4+)

from pathlib import Path

How to specify function types for void (not Void) methods in Java8?

I feel you should be using the Consumer interface instead of Function<T, R>.

A Consumer is basically a functional interface designed to accept a value and return nothing (i.e void)

In your case, you can create a consumer elsewhere in your code like this:

Consumer<Integer> myFunction = x -> {
    System.out.println("processing value: " + x);    
    .... do some more things with "x" which returns nothing...

Then you can replace your myForEach code with below snippet:

public static void myForEach(List<Integer> list, Consumer<Integer> myFunction) 

You treat myFunction as a first-class object.

How to correctly get image from 'Resources' folder in NetBeans

Thanks, Valter Henrique, with your tip i managed to realise, that i simply entered incorrect path to this image. In one of my tries i use

    String pathToImageSortBy = "resources/testDataIcons/filling.png";
    ImageIcon SortByIcon = new ImageIcon(getClass().getClassLoader().getResource(pathToImageSortBy));

But correct way was use name of my project in path to resource

String pathToImageSortBy = "nameOfProject/resources/testDataIcons/filling.png";
ImageIcon SortByIcon = new ImageIcon(getClass().getClassLoader().getResource(pathToImageSortBy));

'foo' was not declared in this scope c++

In C++, your source files are usually parsed from top to bottom in a single pass, so any variable or function must be declared before they can be used. There are some exceptions to this, like when defining functions inline in a class definition, but that's not the case for your code.

Either move the definition of integrate above the one for getSkewNormal, or add a forward declaration above getSkewNormal:

double integrate (double start, double stop, int numSteps, Evaluatable evalObj);

The same applies for sum.

How can I install a package with go get?

First, we need GOPATH

The $GOPATH is a folder (or set of folders) specified by its environment variable. We must notice that this is not the $GOROOT directory where Go is installed.

export GOPATH=$HOME/gocode
export PATH=$PATH:$GOPATH/bin

We used ~/gocode path in our computer to store the source of our application and its dependencies. The GOPATH directory will also store the binaries of their packages.

Then check Go env

You system must have $GOPATH and $GOROOT, below is my Env:

GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0"

Now, you run download go package:

go get [-d] [-f] [-fix] [-t] [-u] [build flags] [packages]

Get downloads and installs the packages named by the import paths, along with their dependencies. For more details you can look here.

How to check SQL Server version


SQLCMD -S (LOCAL) -E -V 16 -Q "IF(ISNULL(CAST(SERVERPROPERTY('ProductMajorVersion') AS INT),0)<11) RAISERROR('You need SQL 2012 or later!',16,1)"

This uses SQLCMD (comes with SQL Server) to connect to the local server instance using Windows auth, throw an error if a version check fails and return the @@ERROR as the command line ERRORLEVEL if >= 16 (and the second line goes to the :ExitFail label if the aforementioned ERRORLEVEL is >= 1).

Watchas, Gotchas & More Info

For SQL 2000+ you can use the SERVERPROPERTY to determine a lot of this info.

While SQL 2008+ supports the ProductMajorVersion & ProductMinorVersion properties, ProductVersion has been around since 2000 (remembering that if a property is not supported the function returns NULL).

If you are interested in earlier versions you can use the PARSENAME function to split the ProductVersion (remembering the "parts" are numbered right to left i.e. PARSENAME('a.b.c', 1) returns c).

Also remember that PARSENAME('a.b.c', 4) returns NULL, because SQL 2005 and earlier only used 3 parts in the version number!

So for SQL 2008+ you can simply use:

    SERVERPROPERTY('ProductVersion') AS ProductVersion,
    CAST(SERVERPROPERTY('ProductMajorVersion')  AS INT) AS ProductMajorVersion,
    CAST(SERVERPROPERTY ('ProductMinorVersion') AS INT) AS ProductMinorVersion;

For SQL 2000-2005 you can use:

    SERVERPROPERTY('ProductVersion') AS ProductVersion,

(the PARSENAME(...,0) is a hack to improve readability)

So a check for a SQL 2000+ version would be:

OR (
AND (CAST(PARSENAME(CAST(SERVERPROPERTY('ProductVersion') AS SYSNAME), CASE WHEN SERVERPROPERTY('ProductVersion') IS NULL THEN 2 ELSE 1 END) AS INT) < 5)  -- R2 (this may need to be 50)
    RAISERROR('You need SQL 2008R2 or later!', 16, 1);

This is a lot simpler if you're only only interested in SQL 2008+ because SERVERPROPERTY('ProductMajorVersion') returns NULL for earlier versions, so you can use:

IF (ISNULL(CAST(SERVERPROPERTY('ProductMajorVersion') AS INT), 0) < 11) -- SQL2012
    RAISERROR('You need SQL 2012 or later!', 16, 1);

And you can use the ProductLevel and Edition (or EngineEdition) properties to determine RTM / SPn / CTPn and Dev / Std / Ent / etc respectively.

    CAST(SERVERPROPERTY('ProductVersion') AS SYSNAME) AS ProductVersion,
    CAST(SERVERPROPERTY('ProductLevel') AS SYSNAME)   AS ProductLevel,
    CAST(SERVERPROPERTY('Edition') AS SYSNAME)        AS Edition,
    CAST(SERVERPROPERTY('EngineEdition') AS INT)      AS EngineEdition;

FYI the major SQL version numbers are:

  • 8 = SQL 2000
  • 9 = SQL 2005
  • 10 = SQL 2008 (and 10.5 = SQL 2008R2)
  • 11 = SQL 2012
  • 12 = SQL 2014
  • 13 = SQL 2016
  • 14 = SQL 2017

And this all works for SQL Azure too!

EDITED: You may also want to check your DB compatibility level since it could be set to a lower compatibility.

IF EXISTS (SELECT * FROM sys.databases WHERE database_id=DB_ID() AND [compatibility_level] < 110)
    RAISERROR('Database compatibility level must be SQL2008R2 or later (110)!', 16, 1)

get the titles of all open windows

Based on the previous answer that give me some errors, finaly I use this code with GetOpenedWindows function:

public class InfoWindow
            public IntPtr Handle = IntPtr.Zero;
            public FileInfo File = new FileInfo( Application.ExecutablePath );
            public string Title = Application.ProductName;
            public override string ToString() {
                return  File.Name + "\t>\t" + Title;

/// <summary>Contains functionality to get info on the open windows.</summary>
public static class RuningWindows
            internal static event EventHandler WindowActivatedChanged;    
            internal static Timer TimerWatcher = new Timer();    
            internal static InfoWindow WindowActive = new InfoWindow();       
            internal static void DoStartWatcher() {
                TimerWatcher.Interval = 500;
                TimerWatcher.Tick += TimerWatcher_Tick;

            /// <summary>Returns a dictionary that contains the handle and title of all the open windows.</summary>
            /// <returns>A dictionary that contains the handle and title of all the open windows.</returns>
            public static IDictionary<IntPtr , InfoWindow> GetOpenedWindows()
                IntPtr shellWindow = GetShellWindow();
                Dictionary<IntPtr , InfoWindow> windows = new Dictionary<IntPtr , InfoWindow>();

                EnumWindows( new EnumWindowsProc( delegate( IntPtr hWnd , int lParam ) {
                    if ( hWnd == shellWindow ) return true;
                    if ( !IsWindowVisible( hWnd ) ) return true;    
                    int length = GetWindowTextLength( hWnd );
                    if ( length == 0 ) return true;    
                    StringBuilder builder = new StringBuilder( length );
                    GetWindowText( hWnd , builder , length + 1 );    
                    var info = new InfoWindow();
                    info.Handle = hWnd;
                    info.File = new FileInfo( GetProcessPath( hWnd ) );
                    info.Title = builder.ToString();    
                    windows[hWnd] = info;
                    return true;    
                } ) , 0 );    
                return windows;

            private delegate bool EnumWindowsProc( IntPtr hWnd , int lParam );  

            public static string GetProcessPath( IntPtr hwnd )
                uint pid = 0;
                GetWindowThreadProcessId( hwnd , out pid );
                if ( hwnd != IntPtr.Zero ) {
                    if ( pid != 0 ) {
                        var process = Process.GetProcessById( (int) pid );
                        if ( process != null ) {
                            return process.MainModule.FileName.ToString();
                return "";

            [DllImport( "USER32.DLL" )]
            private static extern bool EnumWindows( EnumWindowsProc enumFunc , int lParam );

            [DllImport( "USER32.DLL" )]
            private static extern int GetWindowText( IntPtr hWnd , StringBuilder lpString , int nMaxCount );

            [DllImport( "USER32.DLL" )]
            private static extern int GetWindowTextLength( IntPtr hWnd );

            [DllImport( "USER32.DLL" )]
            private static extern bool IsWindowVisible( IntPtr hWnd );

            [DllImport( "USER32.DLL" )]
            private static extern IntPtr GetShellWindow();

            [DllImport( "user32.dll" )]
            private static extern IntPtr GetForegroundWindow();

            //WARN: Only for "Any CPU":
            [DllImport( "user32.dll" , CharSet = CharSet.Auto , SetLastError = true )]
            private static extern int GetWindowThreadProcessId( IntPtr handle , out uint processId );    

            static void TimerWatcher_Tick( object sender , EventArgs e )
                var windowActive = new InfoWindow();
                windowActive.Handle = GetForegroundWindow();
                string path = GetProcessPath( windowActive.Handle );
                if ( string.IsNullOrEmpty( path ) ) return;
                windowActive.File = new FileInfo( path );
                int length = GetWindowTextLength( windowActive.Handle );
                if ( length == 0 ) return;
                StringBuilder builder = new StringBuilder( length );
                GetWindowText( windowActive.Handle , builder , length + 1 );
                windowActive.Title = builder.ToString();
                if ( windowActive.ToString() != WindowActive.ToString() ) {
                    WindowActive = windowActive;
                    if ( WindowActivatedChanged != null ) WindowActivatedChanged( sender , e );
                    Console.WriteLine( "Window: " + WindowActive.ToString() );


Warning: You can only compil/debug under "Any CPU" to access to 32bits Apps...

Free c# QR-Code generator

ZXing is an open source project that can detect and parse a number of different barcodes. It can also generate QR-codes. (Only QR-codes, though).

There are a number of variants for different languages: ActionScript, Android (java), C++, C#, IPhone (Obj C), Java ME, Java SE, JRuby, JSP. Support for generating QR-codes comes with some of those: ActionScript, Android, C# and the Java variants.

Forward slash in Java Regex

Double escaping is required when presented as a string.

Whenever I'm making a new regular expression I do a bunch of tests with online tools, for example:

That website allows you to enter the regular expression, which it'll escape into a string for you, and you can then test it against different inputs.

Why must wait() always be in synchronized block

What is the potential damage if it was possible to invoke wait() outside a synchronized block, retaining it's semantics - suspending the caller thread?

Let's illustrate what issues we would run into if wait() could be called outside of a synchronized block with a concrete example.

Suppose we were to implement a blocking queue (I know, there is already one in the API :)

A first attempt (without synchronization) could look something along the lines below

class BlockingQueue {
    Queue<String> buffer = new LinkedList<String>();

    public void give(String data) {
        notify();                   // Since someone may be waiting in take!

    public String take() throws InterruptedException {
        while (buffer.isEmpty())    // don't use "if" due to spurious wakeups.
        return buffer.remove();

This is what could potentially happen:

  1. A consumer thread calls take() and sees that the buffer.isEmpty().

  2. Before the consumer thread goes on to call wait(), a producer thread comes along and invokes a full give(), that is, buffer.add(data); notify();

  3. The consumer thread will now call wait() (and miss the notify() that was just called).

  4. If unlucky, the producer thread won't produce more give() as a result of the fact that the consumer thread never wakes up, and we have a dead-lock.

Once you understand the issue, the solution is obvious: Use synchronized to make sure notify is never called between isEmpty and wait.

Without going into details: This synchronization issue is universal. As Michael Borgwardt points out, wait/notify is all about communication between threads, so you'll always end up with a race condition similar to the one described above. This is why the "only wait inside synchronized" rule is enforced.

A paragraph from the link posted by @Willie summarizes it quite well:

You need an absolute guarantee that the waiter and the notifier agree about the state of the predicate. The waiter checks the state of the predicate at some point slightly BEFORE it goes to sleep, but it depends for correctness on the predicate being true WHEN it goes to sleep. There's a period of vulnerability between those two events, which can break the program.

The predicate that the producer and consumer need to agree upon is in the above example buffer.isEmpty(). And the agreement is resolved by ensuring that the wait and notify are performed in synchronized blocks.

This post has been rewritten as an article here: Java: Why wait must be called in a synchronized block

Convert JSON string to array of JSON objects in Javascript

Append extra an [ and ] to the beginning and end of the string. This will make it an array. Then use eval() or some safe JSON serializer to serialize the string and make it a real JavaScript datatype.

You should use instead of eval(). eval is only if you're doing some quick debugging/testing.

Java word count program


String str="Simple Java Word Count count Count Program";
Iterable<String> words = Splitter.on(" ").trimResults().split(str);

//google word counter       
Multiset<String> wordsMultiset = HashMultiset.create();
for (String string : words) {   

Set<String> result = wordsMultiset.elementSet();
for (String string : result) {
    System.out.println(string+" X "+wordsMultiset.count(string));

List to array conversion to use ravel() function

create an int array and a list

from array import array
listA = list(range(0,50))
for item in listA:
arrayA = array("i", listA)
for item in arrayA:

Should URL be case sensitive?

All “insensitive”s are boldened for readability.

Domain names are case insensitive according to RFC 4343. The rest of URL is sent to the server via the GET method. This may be case sensitive or not.

Take this page for example, receives GET string /questions/7996919/should-url-be-case-sensitive, sending a HTML document to your browser. is case insensitive because it produces the same result for /QUEStions/7996919/Should-url-be-case-sensitive.

On the other hand, Wikipedia is case sensitive except the first character of the title. The URLs and leads to the same article, but returns 404.

How do I check if the user is pressing a key?

Try this:

import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class Main {

    public static void main(String[] argv) throws Exception {

    JTextField textField = new JTextField();

    textField.addKeyListener(new Keychecker());

    JFrame jframe = new JFrame();


    jframe.setSize(400, 350);



class Keychecker extends KeyAdapter {

    public void keyPressed(KeyEvent event) {

        char ch = event.getKeyChar();




Using Vim's tabs like buffers

Bit late to the party here but surprised I didn't see the following in this list:

:tab sball - this opens a new tab for each open buffer.

:help switchbuf - this controls buffer switching behaviour, try :set switchbuf=usetab,newtab. This should mean switching to the existing tab if the buffer is open, or creating a new one if not.