Programs & Examples On #Argument unpacking

What does ** (double star/asterisk) and * (star/asterisk) do for parameters?

In Python 3.5, you can also use this syntax in list, dict, tuple, and set displays (also sometimes called literals). See PEP 488: Additional Unpacking Generalizations.

>>> (0, *range(1, 4), 5, *range(6, 8))
(0, 1, 2, 3, 5, 6, 7)
>>> [0, *range(1, 4), 5, *range(6, 8)]
[0, 1, 2, 3, 5, 6, 7]
>>> {0, *range(1, 4), 5, *range(6, 8)}
{0, 1, 2, 3, 5, 6, 7}
>>> d = {'one': 1, 'two': 2, 'three': 3}
>>> e = {'six': 6, 'seven': 7}
>>> {'zero': 0, **d, 'five': 5, **e}
{'five': 5, 'seven': 7, 'two': 2, 'one': 1, 'three': 3, 'six': 6, 'zero': 0}

It also allows multiple iterables to be unpacked in a single function call.

>>> range(*[1, 10], *[2])
range(1, 10, 2)

(Thanks to mgilson for the PEP link.)

What does the star operator mean, in a function call?

I find this particularly useful for when you want to 'store' a function call.

For example, suppose I have some unit tests for a function 'add':

def add(a, b): return a + b
tests = { (1,4):5, (0, 0):0, (-1, 3):3 }
for test, result in tests.items():
    print 'test: adding', test, '==', result, '---', add(*test) == result

There is no other way to call add, other than manually doing something like add(test[0], test[1]), which is ugly. Also, if there are a variable number of variables, the code could get pretty ugly with all the if-statements you would need.

Another place this is useful is for defining Factory objects (objects that create objects for you). Suppose you have some class Factory, that makes Car objects and returns them. You could make it so that myFactory.make_car('red', 'bmw', '335ix') creates Car('red', 'bmw', '335ix'), then returns it.

def make_car(*args):
    return Car(*args)

This is also useful when you want to call a superclass' constructor.

Passing an array/list into a Python function

When you define your function using this syntax:

def someFunc(*args):
    for x in args
        print x

You're telling it that you expect a variable number of arguments. If you want to pass in a List (Array from other languages) you'd do something like this:

def someFunc(myList = [], *args):
    for x in myList:
        print x

Then you can call it with this:

items = [1,2,3,4,5]


You need to define named arguments before variable arguments, and variable arguments before keyword arguments. You can also have this:

def someFunc(arg1, arg2, arg3, *args, **kwargs):
    for x in args
        print x

Which requires at least three arguments, and supports variable numbers of other arguments and keyword arguments.

How do you list volumes in docker containers?

Useful variation for docker-compose users:

docker-compose ps -q | xargs docker container inspect  \
   -f '{{ range .Mounts }}{{ .Name }}:{{ .Destination }} {{ end }}' 

This will very neatly output parseable volume info. Example from my wordpress docker-compose:

ubuntu@core $ docker-compose ps -q | xargs docker container inspect  -f '{{ range .Mounts }}{{ .Name }}:{{ .Destination }} {{ end }}' 
core_wpcode:/code core_wphtml:/var/www/html 

The output contains one line for each container, listing the volumes (and mount points) used. Alter the {{ .Name }}:{{ .Destination }} portion to output the info you would like.

If you just want a simple list of volumes, one per line

$ docker-compose ps -q | xargs docker container inspect  \
   -f '{{ range .Mounts }}{{ .Name }} {{ end }}' \
   | xargs -n 1 echo

Great to generate a list of volumes to backup. I use this technique along with Blacklabelops Volumerize to backup all volumes used by all containers within a docker-compose. The docs for Volumerize don't call it out, but you don't need to use it in a persistent container or to use the built-in facilities for starting and stopping services. I prefer to leave critical operations such as backup and service control to the actual user (outside docker). My backups are triggered by the actual (non-docker) user account, and use docker-compose stop to stop services, backup all volumes in use, and finally docker-compose start to restart.

Required attribute HTML5

Safari 7.0.5 still does not support notification for validation of input fields.

To overcome it is possible to write fallback script like this:

To see what HTML5 / CSS3 features are supported by browsers check:

function hasHtml5Validation () {
  //Check if validation supported && not safari
  return (typeof document.createElement('input').checkValidity === 'function') && 
    !("Safari") >= 0 &&"Chrome") < 0);

        var isValid = true;
        var $inputs = $(this).find('[required]');
            var $input = $(this);
                isValid = false;
            return false;


input, select, textarea {
    @include appearance(none);
    border-radius: 0px;

    &.invalid {
        border-color: red !important;

Changing default startup directory for command prompt in Windows 7

changing shortcut under Windows System on 8.1 worked for me - another thing I found is that 'Start In:' WORKS when Advanced -> Run as admin is UNCHECKED, however, if CHECKED, it does not work

Colors in JavaScript console

template system, useful if you want to create colorful line text without creating full style for every block

var tpl = 'background-color:greenyellow; border:3px solid orange; font-size:18px; font-weight: bold;padding:3px 5px;color:';
console.log('%cNo #1' + '.%cRed Text' + '%cBlue Text', 
             tpl+'magenta', tpl+'red', tpl+'blue');

colorful console log

How to create a horizontal loading progress bar?

Worked for me , can try with the same


Play audio file from the assets directory


Your version would work if you had only one file in the assets directory. The asset directory contents are not actually 'real files' on disk. All of them are put together one after another. So, if you do not specify where to start and how many bytes to read, the player will read up to the end (that is, will keep playing all the files in assets directory)

How do I change Android Studio editor's background color?

You can change it by going File => Settings (Shortcut CTRL+ ALT+ S) , from Left panel Choose Appearance , Now from Right Panel choose theme.

enter image description here

Android Studio 2.1

Preference -> Search for Appearance -> UI options , Click on DropDown Theme

enter image description here

Android 2.2

Android studio -> File -> Settings -> Appearance & Behavior -> Look for UI Options


Import External Themes

You can download custom theme from this website. Choose your theme, download it. To set theme Go to Android studio -> File -> Import Settings -> Choose the .jar file downloaded.

What is useState() in React?

useState is one of the hooks available in React v16.8.0. It basically lets you turn your otherwise non-stateful/functional components to one that can have its own state.

At the very basic level, it's used this way:

const [isLoading, setLoading] = useState(true);

This then lets you call setLoading passing a boolean value. It's a cool way of having "stateful" functional component.

How to fire a button click event from JavaScript in ASP.NET; 

works for me. Enjoy.

How to test Spring Data repositories?

If you're using Spring Boot, you can simply use @SpringBootTest to load in your ApplicationContext (which is what your stacktrace is barking at you about). This allows you to autowire in your spring-data repositories. Be sure to add @RunWith(SpringRunner.class) so the spring-specific annotations are picked up:

public class OrphanManagementTest {

  private UserRepository userRepository;

  public void saveTest() {
    User user = new User("Tom");;

You can read more about testing in spring boot in their docs.

Set mouse focus and move cursor to end of input using jQuery

like other said, clear and fill worked for me:

    var elem = $('#input_field');
    var val = elem.val();

How can I convert integer into float in Java?

You just need to transfer the first value to float, before it gets involved in further computations:

float z = x * 1.0 / y;

How do getters and setters work?

Tutorial is not really required for this. Read up on encapsulation

private String myField; //"private" means access to this is restricted

public String getMyField()
     //include validation, logic, logging or whatever you like here
    return this.myField;
public void setMyField(String value)
     //include more logic
     this.myField = value;

Spring @ContextConfiguration how to put the right location for the xml

@RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration(locations = {"/Beans.xml"}) public class DemoTest{}

require_once :failed to open stream: no such file or directory

The error pretty much explains what the problem is: you are trying to include a file that is not there.

Try to use the full path to the file, using realpath(), and use dirname(__FILE__) to get your current directory:

require_once(realpath(dirname(__FILE__) . '/../includes/'));

Maven Unable to locate the Javac Compiler in:

None of the current answers helped me here. We were getting something like:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:
    #.#.#:compile (default-compile) on project Streaming_Test: Compilation failure
[ERROR] Unable to locate the Javac Compiler in:
[ERROR] /opt/java/J7.0/../lib/tools.jar

This happens because the Java installation has determined that it is a JRE installation. It's expecting there to be JDK stuff above the JRE subdirectory, hence the ../lib in the path. Our tools.jar is in $JAVA_HOME/lib/tools.jar not in $JAVA_HOME/../lib/tools.jar.

Unfortunately, we do not have an option to install a JDK on our OS (don't ask) so that wasn't an option. I fixed the problem by adding the following to the maven pom.xml:

      <fork>true</fork>  <!-- not sure if this is also needed -->
      <!--        ^^^^^^^^^^^^^^^^^^^^^^ -->

By pointing the executable to the right place this at least got past our compilation failures.

Android camera intent

I found a pretty simple way to do this. Use a button to open it using an on click listener to start the function openc(), like this:

String fileloc;
private void openc()
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    File f = null;
        f = File.createTempFile("temppic",".jpg",getApplicationContext().getCacheDir());
        if (takePictureIntent.resolveActivity(getPackageManager()) != null)
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,FileProvider.getUriForFile(profile.this, BuildConfig.APPLICATION_ID+".provider",f));
            fileloc = Uri.fromFile(f)+"";
            Log.d("texts", "openc: "+fileloc);
            startActivityForResult(takePictureIntent, 3);
    catch (IOException e) 

protected void onActivityResult(int requestCode, int resultCode, Intent data) 
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode == 3 && resultCode == RESULT_OK) {
        Log.d("texts", "onActivityResult: "+fileloc);
        // fileloc is the uri of the file so do whatever with it

You can do whatever you want with the uri location string. For instance, I send it to an image cropper to crop the image.

Chaining multiple filter() in Django, is this a bug?

From Django docs :

To handle both of these situations, Django has a consistent way of processing filter() calls. Everything inside a single filter() call is applied simultaneously to filter out items matching all those requirements. Successive filter() calls further restrict the set of objects, but for multi-valued relations, they apply to any object linked to the primary model, not necessarily those objects that were selected by an earlier filter() call.

  • It is clearly said that multiple conditions in a single filter() are applied simultaneously. That means that doing :
objs = Mymodel.objects.filter(a=True, b=False)

will return a queryset with raws from model Mymodel where a=True AND b=False.

  • Successive filter(), in some case, will provide the same result. Doing :
objs = Mymodel.objects.filter(a=True).filter(b=False)

will return a queryset with raws from model Mymodel where a=True AND b=False too. Since you obtain "first" a queryset with records which have a=True and then it's restricted to those who have b=False at the same time.

  • The difference in chaining filter() comes when there are multi-valued relations, which means you are going through other models (such as the example given in the docs, between Blog and Entry models). It is said that in that case (...) they apply to any object linked to the primary model, not necessarily those objects that were selected by an earlier filter() call.

Which means that it applies the successives filter() on the target model directly, not on previous filter()

If I take the example from the docs :


remember that it's the model Blog that is filtered, not the Entry. So it will treat the 2 filter() independently.

It will, for instance, return a queryset with Blogs, that have entries that contain 'Lennon' (even if they are not from 2008) and entries that are from 2008 (even if their headline does not contain 'Lennon')

THIS ANSWER goes even further in the explanation. And the original question is similar.

How do I put variables inside javascript strings?

As of node.js >4.0 it gets more compatible with ES6 standard, where string manipulation greatly improved.

The answer to the original question can be as simple as:

var s = `hello ${my_name}, how are you doing`;
// note: tilt ` instead of single quote '

Where the string can spread multiple lines, it makes templates or HTML/XML processes quite easy. More details and more capabilitie about it: Template literals are string literals at

How can I print the contents of an array horizontally?

private int[,] MirrorH(int[,] matrix)               //the method will return mirror horizintal of matrix
    int[,] MirrorHorizintal = new int[4, 4];
    for (int i = 0; i < 4; i++)
        for (int j = 0; j < 4; j ++)
            MirrorHorizintal[i, j] = matrix[i, 3 - j];
    return MirrorHorizintal;

Weblogic Transaction Timeout : how to set in admin console in WebLogic AS 8.1

If you don't want to change the domain-wide default timeout, your best option is to change the deployment descriptor by setting the trans-timeout-seconds attribute in the weblogic-ejb-jar.xml - see

This overrides the "Timeout Seconds" default, only for this specific EJB, while leaving all other EJB unaffected.

Replacement for deprecated sizeWithFont: in iOS 7?

Try this syntax:

NSAttributedString *attributedText =
    [[NSAttributedString alloc] initWithString:text 
                                    attributes:@{NSFontAttributeName: font}];

Properly close mongoose's connection once you're done

Just as Jake Wilson said: You can set the connection to a variable then disconnect it when you are done:

let db;
    db = dbConnection;

function afterwards(){

    //do stuff


or if inside Async function:

(async ()=>{
    const db = await mongoose.connect('mongodb://localhost:27017/somedb', { useMongoClient: 
                  true })

    //do stuff


otherwise when i was checking it in my environment it has an error.

Can I get the name of the currently running function in JavaScript?

An updated answer to this can can be found over at this answer:

and, if you don't feel like clicking:

function test() {
  var z =;

Creating a JSON dynamically with each input value using jquery

May be this will help, I'd prefer pure JS wherever possible, it improves the performance drastically as you won't have lots of JQuery function calls.

var obj = [];
var elems = $("input[class=email]");

for (i = 0; i < elems.length; i += 1) {
    var id = this.getAttribute('title');
    var email = this.value;
    tmp = {
        'title': id,
        'email': email


How do I retrieve my MySQL username and password?

While you can't directly recover a MySQL password without bruteforcing, there might be another way - if you've used MySQL Workbench to connect to the database, and have saved the credentials to the "vault", you're golden.

On Windows, the credentials are stored in %APPDATA%\MySQL\Workbench\workbench_user_data.dat - encrypted with CryptProtectData (without any additional entropy). Decrypting is easy peasy:

std::vector<unsigned char> decrypt(BYTE *input, size_t length) {
    DATA_BLOB inblob { length, input };
    DATA_BLOB outblob;

    if (!CryptUnprotectData(&inblob, NULL, NULL, NULL, NULL, CRYPTPROTECT_UI_FORBIDDEN, &outblob)) {
            throw std::runtime_error("Couldn't decrypt");

    std::vector<unsigned char> output(length);
    memcpy(&output[0], outblob.pbData, outblob.cbData);

    return output;

Or you can check out this DonationCoder thread for source + executable of a quick-and-dirty implementation.

How to pass integer from one Activity to another?

It's simple. On the sender side, use Intent.putExtra:

Intent myIntent = new Intent(A.this, B.class);
myIntent.putExtra("intVariableName", intValue);

On the receiver side, use Intent.getIntExtra:

 Intent mIntent = getIntent();
 int intValue = mIntent.getIntExtra("intVariableName", 0);

Suppress/ print without b' prefix for bytes in Python 3

If the data is in an UTF-8 compatible format, you can convert the bytes to a string.

>>> import curses
>>> print(str(curses.version, "utf-8"))

Optionally convert to hex first, if the data is not already UTF-8 compatible. E.g. when the data are actual raw bytes.

from binascii import hexlify
from codecs import encode  # alternative
>>> print(hexlify(b"\x13\x37"))
>>> print(str(hexlify(b"\x13\x37"), "utf-8"))
>>>> print(str(encode(b"\x13\x37", "hex"), "utf-8"))

Using ffmpeg to change framerate

You can use this command and the video duration is still unaltered.

ffmpeg -i input.mp4 -r 24 output.mp4

ImportError: No module named dateutil.parser

None of the solutions worked for me. If you are using PIP do:

pip install pycrypto==2.6.1

How do you get the string length in a batch file?

You can do it in two lines, fully in a batch file, by writing the string to a file and then getting the length of the file. You just have to subtract two bytes to account for the automatic CR+LF added to the end.

Let's say your string is in a variable called strvar:

ECHO %strvar%> tempfile.txt
FOR %%? IN (tempfile.txt) DO ( SET /A strlength=%%~z? - 2 )

The length of the string is now in a variable called strlength.

In slightly more detail:

  • FOR %%? IN (filename) DO ( ... : gets info about a file
  • SET /A [variable]=[expression] : evaluate the expression numerically
  • %%~z? : Special expression to get the length of the file

To mash the whole command in one line:

ECHO %strvar%>x&FOR %%? IN (x) DO SET /A strlength=%%~z? - 2&del x

How to get a value of an element by name instead of ID

What element is used for the part with a green background? Just type the name of the element without "<" and ">" characters. For example type P, not <P> if the answer is the <P> element.

Installing Android Studio, does not point to a valid JVM installation error

Don't include bin folder while coping the path for Java_home.

Refresh an page on button click

That on code behind redirect to the same page.


What does the regex \S mean in JavaScript?

\S matches anything but a whitespace, according to this reference.

Are list-comprehensions and functional functions faster than "for loops"?

I wrote a simple script that test the speed and this is what I found out. Actually for loop was fastest in my case. That really suprised me, check out bellow (was calculating sum of squares).

from functools import reduce
import datetime

def time_it(func, numbers, *args):
    start_t =
    for i in range(numbers):
    print (

def square_sum1(numbers):
    return reduce(lambda sum, next: sum+next**2, numbers, 0)

def square_sum2(numbers):
    a = 0
    for i in numbers:
        i = i**2
        a += i
    return a

def square_sum3(numbers):
    sqrt = lambda x: x**2
    return sum(map(sqrt, numbers))

def square_sum4(numbers):
    return(sum([int(i)**2 for i in numbers]))

time_it(square_sum1, 100000, [1, 2, 5, 3, 1, 2, 5, 3])
time_it(square_sum2, 100000, [1, 2, 5, 3, 1, 2, 5, 3])
time_it(square_sum3, 100000, [1, 2, 5, 3, 1, 2, 5, 3])
time_it(square_sum4, 100000, [1, 2, 5, 3, 1, 2, 5, 3])
0:00:00.302000 #Reduce
0:00:00.144000 #For loop
0:00:00.318000 #Map
0:00:00.390000 #List comprehension

Jquery Ajax beforeSend and success,error & complete

Maybe you can try the following :

var i = 0;
function AjaxSendForm(url, placeholder, form, append) {
var data = $(form).serialize();
append = (append === undefined ? false : true); // whatever, it will evaluate to true or false only
    type: 'POST',
    url: url,
    data: data,
    beforeSend: function() {
        // setting a timeout
    success: function(data) {
        if (append) {
        } else {
    error: function(xhr) { // if error occured
        alert("Error occured.please try again");
        $(placeholder).append(xhr.statusText + xhr.responseText);
    complete: function() {
        if (i <= 0) {
    dataType: 'html'

This way, if the beforeSend statement is called before the complete statement i will be greater than 0 so it will not remove the class. Then only the last call will be able to remove it.

I cannot test it, let me know if it works or not.

How to get current PHP page name

In your case you can use __FILE__ variable !
It should help.
It is one of predefined.
Read more about predefined constants in PHP

adding onclick event to dynamically added button?

Try this:

var inputTag = document.createElement("div");              
inputTag.innerHTML = "<input type = 'button' value = 'oooh' onClick = 'your_function_name()'>";    

This creates a button inside a DIV which works perfectly!

SSRS custom number format

am assuming that you want to know how to format numbers in SSRS

Just right click the TextBox on which you want to apply formatting, go to its expression.

suppose its expression is something like below


then do this




difference between the two is that former one would make 4 as 4 and later one would make 4 as 04.00

this should give you an idea.

also: you might have to convert your field into a numerical one. i.e.


so: 0 in format expression means, when no number is present, place a 0 there and # means when no number is present, leave it. Both of them works same when numbers are present ie. 45.6567 would be 45.65 for both of them:


if you want to apply variable formatting on the same column based on row values i.e. you want myField to have no formatting when it has no decimal value but formatting with double precision when it has decimal then you can do it through logic. (though you should not be doing so)

Go to the appropriate textbox and go to its expression and do this:

=IIF((Fields!myField.Value - CInt(Fields!myField.Value)) > 0, 
    Format(Fields!myField.Value, "##.##"),Fields!myField.Value)

so basically you are using IIF(condition, true,false) operator of SSRS, ur condition is to check whether the number has decimal value, if it has, you apply the formatting and if no, you let it as it is.

this should give you an idea, how to handle variable formatting.

Windows.history.back() + location.reload() jquery

window.history.back() does not support reload or refresh of the page. But you can use following if you are okay with an extra refresh


However a real complete solution would be as follows: I wrote a service to keep track of previous page and then navigate to that page with reload:true

Here is how i did it.

'use strict';

    .factory('RouterTracker', function RouterTracker($rootScope) {
          var routeHistory = [];
          var service = {
            getRouteHistory: getRouteHistory

          $rootScope.$on('$stateChangeSuccess', function (ev, to, toParams, from, fromParams) {
              routeHistory = [];
              routeHistory.push({route: from, routeParams: fromParams});

          function getRouteHistory() {
            return routeHistory;

          return service;       

Make sure you have included this js file from you index.html

<script src="scripts/components/util/route.service.js"></script>

Now from you stateprovider or controller you can access this service and navigate

var routeHistory = RouterTracker.getRouteHistory();    
$state.go(routeHistory[0], null, { reload: true });

or alternatively even perform checks and conditional routing

var routeHistory = RouterTracker.getRouteHistory();    
if(routeHistory[0] == 'seat') {
      $state.go('seat', null, { reload: true });
} else {

Make sure you have added RouterTracker as an argument in your function in my case it was :

.state('', {
                parent: 'seat',
                url: '/new',
                data: {
                    authorities: ['ROLE_USER'],
                onEnter: ['$stateParams', '$state', '$uibModal', 'RouterTracker', function($stateParams, $state, $uibModal, RouterTracker) {
      //....Open dialog.....
 }).result.then(function(result) {
            var routeHistory = RouterTracker.getRouteHistory();    
            $state.go(routeHistory[0], null, { reload: true });
 }, function() {

Sending HTTP POST Request In Java

A simple way using Apache HTTP Components is

            .bodyForm(Form.form().add("id", "10").build())

Take a look at the Fluent API

Reading a .txt file using Scanner class in Java

  1. Make sure the filename is correct (proper capitalisation, matching extension etc - as already suggested).

  2. Use the Class.getResource method to locate your file in the classpath - don't rely on the current directory:

    URL url = insertionSort.class.getResource("10_Random");
    File file = new File(url.toURI());
  3. Specify the absolute file path via command-line arguments:

    File file = new File(args[0]);

In Eclipse:

  1. Choose "Run configurations"
  2. Go to the "Arguments" tab
  3. Put your "c:/my/file/is/here/10_Random.txt.or.whatever" into the "Program arguments" section

change figure size and figure format in matplotlib

If you need to change the figure size after you have created it, use the methods

fig = plt.figure()

where value_height and value_width are in inches. For me this is the most practical way.

Subtract minute from DateTime in SQL Server 2005

I spent a while trying to do the same thing, trying to subtract the hours:minutes from datetime - here's how I did it:

convert( varchar, cast((RouteMileage / @average_speed) as integer))+ ':' +  convert( varchar, cast((((RouteMileage / @average_speed) - cast((RouteMileage / @average_speed) as integer)) * 60) as integer)) As TravelTime,

dateadd( n, -60 * CAST( (RouteMileage / @average_speed) AS DECIMAL(7,2)), @entry_date) As DepartureTime 


DeliveryDate                TravelTime             DepartureTime
2012-06-02 12:00:00.000       25:49         2012-06-01 10:11:00.000

Create a custom callback in JavaScript

function loadData(callback) {

    //execute other requirement

    if(callback && typeof callback == "function"){


   //execute callback


HTML iframe - disable scroll

I solved the same issue with this css:


Git - How to fix "corrupted" interactive rebase?

I got stuck in this. I created the head-name file, and then I ran into another error saying it couldn't find the onto file, so I created that file. Then I got another error saying could not read '.git/rebase-apply/onto': No such file or directory.

So I looked at the git documentation for rebasing and found another command:

git rebase --quit

This set me back on my branch with no changes, and I could start my rebase over again, good as new.

Check existence of directory and create if doesn't exist

Here's the simple check, and creates the dir if doesn't exists:

## Provide the dir name(i.e sub dir) that you want to create under main dir:
output_dir <- file.path(main_dir, sub_dir)

if (!dir.exists(output_dir)){
} else {
    print("Dir already exists!")

How to count no of lines in text file and store the value into a variable using batch script?

One nice surprise is for one who has git bash on his windows: just plain old linux wc -l <filename> will works for you there

Best way to format if statement with multiple conditions

I prefer Option A

bool a, b, c;

if( a && b && c )
   //This is neat & readable

If you do have particularly long variables/method conditions you can just line break them

if( VeryLongConditionMethod(a) &&
    VeryLongConditionMethod(b) &&
   //This is still readable

If they're even more complicated, then I'd consider doing the condition methods separately outside the if statement

bool aa = FirstVeryLongConditionMethod(a) && SecondVeryLongConditionMethod(a);
bool bb = FirstVeryLongConditionMethod(b) && SecondVeryLongConditionMethod(b);
bool cc = FirstVeryLongConditionMethod(c) && SecondVeryLongConditionMethod(c);

if( aa && bb && cc)
   //This is again neat & readable
   //although you probably need to sanity check your method names ;)

IMHO The only reason for option 'B' would be if you have separate else functions to run for each condition.


if( a )
    if( b )
        //Do Something Else B
   //Do Something Else A

Installing RubyGems in Windows

I recommend you just use rubyinstaller

It is recommended by the official Ruby page - see

Ways of Installing Ruby

We have several tools on each major platform to install Ruby:

  • On Linux/UNIX, you can use the package management system of your distribution or third-party tools (rbenv and RVM).
  • On OS X machines, you can use third-party tools (rbenv and RVM).
  • On Windows machines, you can use RubyInstaller.

Is it possible to override / remove background: none!important with jQuery?

With a <script> right after the <style> that applies the !important things, you should be able to do something like this:

var lastStylesheet = document.styleSheets[document.styleSheets.length - 1];
lastStylesheet.disabled = true;

document.write('<style type="text/css">');
// Call fixBackground for each element that needs fixing

lastStylesheet.disabled = false;

function fixBackground(el) {
    document.write('html #' + + ' { background-image: ' +
        document.defaultView.getComputedStyle(el).backgroundImage +
        ' !important; }');

This probably depends on what kind of browser compatibility you need, though.

Artisan migrate could not find driver

if you've installed php and mysql in your linux machine, php needs php-mysql extention to communicate with mysql. so make sure you've also installed this extention using:

sudo yum install php-mysql in redhat based machines.


sudo apt-get install php-mysql in debian machines.

Angular: 'Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays'

As the error messages stated, ngFor only supports Iterables such as Array, so you cannot use it for Object.


private extractData(res: Response) {
  let body = <Afdelingen[]>res.json();
  return body || {};       // here you are return an object


private extractData(res: Response) {
  let body = <Afdelingen[]>res.json().afdelingen;    // return array from json file
  return body || [];     // also return empty array if there is no data

JPA getSingleResult() or null

The undocumented method uniqueResultOptional in org.hibernate.query.Query should do the trick. Instead of having to catch a NoResultException you can just call query.uniqueResultOptional().orElse(null).

Why do I get access denied to data folder when using adb?

before we start, do you have a rooted phone? if not, I strongly suggest that it's time you make the jump. 99% of the tutorials that help you to do this require that you have a rooted phone (I know b/c I spent about an hour searching for a way to do it without having a rooted phone.. couldn't find any..) also if you think about it, your iPhone also has to be rooted to do this same task. So it's totally reasonable. More about rooting at end of answer.

from your command line type:

adb shell

this takes you to your android shell comand line (you should see something like this: shell@android:/ $ now type:

shell@android:/ $run-as com.domain.yourapp

this should take you directly to the data directory of com.domain.yourapp:

shell@android:/data/data/com.domain.yourapp $ 

if it doesn't (ie if you get an error) then you probably don't have a rooted phone, or you haven't used your root user privileges. To use your root user privileges, type su on the adb command line and see what happens, if you get an error, then you're phone is not rooted. If it's not, root it first then continue these instructions.

from there you can type ls and you'll see all the directories including the dbs:

shell@android:/data/data/com.domain.yourapp $ ls


after that you can use sqlite3 to browse the dbase.. if you don't have it installed (you can find it out by typing sqlite3, if you get command not found then you'll have to install it. To install sqlite, follow instructions here.

about rooting: if you've never rooted your phone before, and you're worried about it screwing your phone, I can tell you with full confidence that there is nothing to worry about. there are tonnes of quick and easy phone rooting tutorials for pretty much all the new and old models out there, and you can root your phone even if you have a mac (I rooted my s3 with my mac).

how to fix the issue "Command /bin/sh failed with exit code 1" in iphone

I'll list things I did that did not work for me and finally what did

First, the accepted answer of Run script only when installing did not work.

Deleting derived data did not work.

What did work:

  1. I added a new build phase in Build Phases

  2. New Copy Files Phase

  3. Drag & Drop the chosen framework into the drop target

  4. Set the 'Destination' to Frameworks

Credit due to Kevin Le's Medium post

View the change history of a file using Git versioning

If you're using the git GUI (on Windows) under the Repository menu you can use "Visualize master's History". Highlight a commit in the top pane and a file in the lower right and you'll see the diff for that commit in the lower left.

How do I add a resources folder to my Java project in Eclipse

Build Path -> Configure Build Path -> Libraries (Tab) -> Add Class Folder, then select your folder or create one.

How to install maven on redhat linux

Pretty much what others said, but using "~/.bash_profile" and step by step (for beginners):

  1. Move to home folder and create a new folder for maven artifacts:
    • cd ~ && mkdir installed-packages
  2. Go to and wget the latest artifact:
    • If you don't have wget installed: sudo yum install -y wget
    • cd ~/installed-packages
    • wget
  3. Uncompress the downloaded file:
    • tar -xvf apache-maven-3.5.0-bin.tar.gz
  4. Create a symbolic link of the uncompressed file:
    • ln -s ~/installed-packages/apache-maven-3.5.0 /usr/local/apache-maven
  5. Edit ~/.bash_profile (This is where environment variables are commonly stored):
    • vi ~/.bash_profile
    • Add the variable: MVN_HOME=/usr/local/apache-maven (do this before PATH variable is defined)
      • (For those who don't know vi tool: Press i key to enable insert mode)
    • Go to the end of the line where PATH variable is defined and append the following: :$MVN_HOME:$MVN_HOME/bin
    • Save changes
      • (For those who don't know vi tool: Press esc key to exit insert mode and :wq! to save and quit file)
  6. Reload environment variables:
    • source ~/.bash_profile
  7. Confirm that maven command now works properly:
    • mvn --help

Visual Studio: ContextSwitchDeadlock

You can solve this by unchecking contextswitchdeadlock from

Debug->Exceptions ... -> Expand MDA node -> uncheck -> contextswitchdeadlock

How to check Oracle patches are installed?

Here is an article on how to check and or install new patches :

To find the OPatch tool setup your database enviroment variables and then issue this comand:

> pwd

To list all the patches applies to your database use the lsinventory option:

[oracle@DCG023 8828328]$ opatch lsinventory
Oracle Interim Patch Installer version
Copyright (c) 2012, Oracle Corporation. All rights reserved.

Oracle Home : /u00/product/11.2.0/dbhome_1
Central Inventory : /u00/oraInventory
from : /u00/product/11.2.0/dbhome_1/oraInst.loc
OPatch version :
OUI version :
Log file location : /u00/product/11.2.0/dbhome_1/cfgtoollogs/opatch/opatch2013-11-13_13-55-22PM_1.log
Lsinventory Output file location : /u00/product/11.2.0/dbhome_1/cfgtoollogs/opatch/lsinv/lsinventory2013-11-13_13-55-22PM.txt

Installed Top-level Products (1):
Oracle Database 11g
There are 1 products installed in this Oracle Home.

Interim patches (1) :
Patch 8405205 : applied on Mon Aug 19 15:18:04 BRT 2013
Unique Patch ID: 11805160
Created on 23 Sep 2009, 02:41:32 hrs PST8PDT
Bugs fixed:

OPatch succeeded.

To list the patches using sql :

select * from registry$history;

Swap x and y axis without manually swapping values

In Numbers, click on the chart. Then in the BOTTOM LEFT corner there is the the option to either 'Plot Rows as Series'or 'Plot Columns as series'

svn : how to create a branch from certain revision of trunk

$ svn copy \ \
   -m "Creating a private branch of /calc/trunk."

Where 192 is the revision you specify

You can find this information from the SVN Book, specifically here on the page about svn copy

Sorting rows in a data table

Or, if you can use a DataGridView, you could just call Sort(column, direction):

namespace Sorter
    using System;
    using System.ComponentModel;
    using System.Windows.Forms;

    public partial class Form1 : Form
        public Form1()

        private void Form1_Load(object sender, EventArgs e)
            this.dataGridView1.Rows.Add("Abc", 5);
            this.dataGridView1.Rows.Add("Def", 8);
            this.dataGridView1.Rows.Add("Ghi", 3);

Which would give you the desired result:

Debugger view

How to replace deprecated

There's no need for you to use super-call of the ActionBarDrawerToggle which requires the Toolbar. This means instead of using the following constructor:

ActionBarDrawerToggle(Activity activity, DrawerLayout drawerLayout, Toolbar toolbar, int openDrawerContentDescRes, int closeDrawerContentDescRes)

You should use this one:

ActionBarDrawerToggle(Activity activity, DrawerLayout drawerLayout, int openDrawerContentDescRes, int closeDrawerContentDescRes)

So basically the only thing you have to do is to remove your custom drawable:

super(mActivity, mDrawerLayout, R.string.ns_menu_open, R.string.ns_menu_close);

More about the "new" ActionBarDrawerToggle in the Docs (click).

Failed to install *.apk on device 'emulator-5554': EOF

Neither above helped me, instead, I connected my phone through the back USB hubs (I used forward USB hubs previously), and this helped me!

Parsing time string in Python

In [117]: datetime.datetime.strptime?
Type:           builtin_function_or_method
Base Class:     <type 'builtin_function_or_method'>
String Form:    <built-in method strptime of type object at 0x9a2520>
Namespace:      Interactive
    string, format -> new datetime parsed from a string (like time.strptime()).

Get hostname of current request in node.js Express

Here's an alternate


Read about it in the Express Docs.

Looping over a list in Python

Try this,

x in mylist is better and more readable than x in mylist[:] and your len(x) should be equal to 3.

>>> mylist = [[1,2,3],[4,5,6,7],[8,9,10]]
>>> for x in mylist:
...      if len(x)==3:
...        print x
[1, 2, 3]
[8, 9, 10]

or if you need more pythonic use list-comprehensions

>>> [x for x in mylist if len(x)==3]
[[1, 2, 3], [8, 9, 10]]

How to decrypt a password from SQL server?

A quick google indicates that pwdencrypt() is not deterministic, and your statement select pwdencrypt('AAAA') returns a different value on my installation!

See also this article

C# HttpWebRequest of type "application/x-www-form-urlencoded" - how to send '&' character in content body?

Since your content-type is application/x-www-form-urlencoded you'll need to encode the POST body, especially if it contains characters like & which have special meaning in a form.

Try passing your string through HttpUtility.UrlEncode before writing it to the request stream.

Here are a couple links for reference.

How to list the properties of a JavaScript object?

Building on the accepted answer.

If the Object has properties you want to call say .properties() try!

var keys = Object.keys(myJSONObject);

for (var j=0; j < keys.length; j++) {

How to get the selected row values of DevExpress XtraGrid?

var rowHandle = gridView.FocusedRowHandle;

var obj = gridView.GetRowCellValue(rowHandle, "FieldName");

//For example  
int val= Convert.ToInt32(gridView.GetRowCellValue(rowHandle, "FieldName"));

CSS: Position loading indicator in the center of the screen

This is what I've done for Angular 4:

<style type="text/css">  
  .centered {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    transform: -webkit-translate(-50%, -50%);
    transform: -moz-translate(-50%, -50%);
    transform: -ms-translate(-50%, -50%);


        <div class="centered">

checking if number entered is a digit in jquery

var yourfield = $('fieldname').val();

if($.isNumeric(yourfield)) { 
        console.log('IM A NUMBER');
} else { 
        console.log('not a number');


How to find list intersection?

If, by Boolean AND, you mean items that appear in both lists, e.g. intersection, then you should look at Python's set and frozenset types.

ASP.NET DateTime Picker

There is an easy, out of the box implementation: the HTML 5 input type="date" and the other date-related input types.

Okay, you can't style the controls that much and it doesn't work on every browser, but still it can be a very good option in the long term if all modern browsers support it and don't want to include heavy libraries that don't always work that good on mobile devices.

How to securely save username/password (local)?

I wanted to encrypt and decrypt the string as a readable string.

Here is a very simple quick example in C# Visual Studio 2019 WinForms based on the answer from @Pradip.

Right click project > properties > settings > Create a username and password setting.

enter image description here

Now you can leverage those settings you just created. Here I save the username and password but only encrypt the password in it's respectable value field in the user.config file.

Example of the encrypted string in the user.config file.

<?xml version="1.0" encoding="utf-8"?>
            <setting name="username" serializeAs="String">
            <setting name="password" serializeAs="String">

enter image description here

Full Code

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Security;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace secure_password_store
    public partial class Form1 : Form
        public Form1()

        private void Exit_Click(object sender, EventArgs e)

        private void Login_Click(object sender, EventArgs e)
            if (checkBox1.Checked == true)
                Properties.Settings.Default.username = textBox1.Text;
                Properties.Settings.Default.password = EncryptString(ToSecureString(textBox2.Text));
            else if (checkBox1.Checked == false)
                Properties.Settings.Default.username = "";
                Properties.Settings.Default.password = "";
            MessageBox.Show("{\"data\": \"some data\"}","Login Message Alert",MessageBoxButtons.OK, MessageBoxIcon.Information);
        private void DecryptString_Click(object sender, EventArgs e)
            SecureString password = DecryptString(Properties.Settings.Default.password);
            string readable = ToInsecureString(password);
            textBox4.AppendText(readable + Environment.NewLine);
        private void Form_Load(object sender, EventArgs e)
            //textBox1.Text = "UserName";
            //textBox2.Text = "Password";
            if (Properties.Settings.Default.username != string.Empty)
                textBox1.Text = Properties.Settings.Default.username;
                checkBox1.Checked = true;
                SecureString password = DecryptString(Properties.Settings.Default.password);
                string readable = ToInsecureString(password);
                textBox2.Text = readable;

        static byte[] entropy = Encoding.Unicode.GetBytes("SaLtY bOy 6970 ePiC");

        public static string EncryptString(SecureString input)
            byte[] encryptedData = ProtectedData.Protect(Encoding.Unicode.GetBytes(ToInsecureString(input)),entropy,DataProtectionScope.CurrentUser);
            return Convert.ToBase64String(encryptedData);

        public static SecureString DecryptString(string encryptedData)
                byte[] decryptedData = ProtectedData.Unprotect(Convert.FromBase64String(encryptedData),entropy,DataProtectionScope.CurrentUser);
                return ToSecureString(Encoding.Unicode.GetString(decryptedData));
                return new SecureString();

        public static SecureString ToSecureString(string input)
            SecureString secure = new SecureString();
            foreach (char c in input)
            return secure;

        public static string ToInsecureString(SecureString input)
            string returnValue = string.Empty;
            IntPtr ptr = System.Runtime.InteropServices.Marshal.SecureStringToBSTR(input);
                returnValue = System.Runtime.InteropServices.Marshal.PtrToStringBSTR(ptr);
            return returnValue;

        private void EncryptString_Click(object sender, EventArgs e)
            Properties.Settings.Default.password = EncryptString(ToSecureString(textBox2.Text));
            textBox3.AppendText(Properties.Settings.Default.password.ToString() + Environment.NewLine);

JPA With Hibernate Error: [PersistenceUnit: JPA] Unable to build EntityManagerFactory

You don't need both hibernate.cfg.xml and persistence.xml in this case. Have you tried removing hibernate.cfg.xml and mapping everything in persistence.xml only?

But as the other answer also pointed out, this is not okay like this:

@JoinColumn(name = "categoria") 
private String id;

Didn't you want to use @Column instead?

How to create an Observable from static data similar to http one in Angular?

Things seem to have changed since Angular 2.0.0

import { Observable } from 'rxjs/Observable';
import { Subscriber } from 'rxjs/Subscriber';
// ...
public fetchModel(uuid: string = undefined): Observable<string> {
  if(!uuid) {
    return new Observable<TestModel>((subscriber: Subscriber<TestModel>) => TestModel())).map(o => JSON.stringify(o));
  else {
    return this.http.get("http://localhost:8080/myapp/api/model/" + uuid)
            .map(res => res.text());

The .next() function will be called on your subscriber.

java.sql.SQLException: No suitable driver found for jdbc:microsoft:sqlserver

I was having the same error, but had a proper connection string. My problem was that the driver was not being used, therefore was optimized out of the compiled war.

Be sure to import the driver:


And then to force it to be included in the final war, you can do something like this:


That line is in the original question. This will also work:

SQLServerDriver driver = new SQLServerDriver();

Print current call stack from a method in Python code

Here's an example of getting the stack via the traceback module, and printing it:

import traceback

def f():

def g():
    for line in traceback.format_stack():


# Prints:
# File "", line 10, in <module>
#     f()
# File "", line 4, in f
#     g()
# File "", line 7, in g
#     for line in traceback.format_stack():

If you really only want to print the stack to stderr, you can use:


Or to print to stdout (useful if want to keep redirected output together), use:


But getting it via traceback.format_stack() lets you do whatever you like with it.

JS file gets a net::ERR_ABORTED 404 (Not Found)

As mentionned in comments: you need a way to send your static files to the client. This can be achieved with a reverse proxy like Nginx, or simply using express.static().

Put all your "static" (css, js, images) files in a folder dedicated to it, different from where you put your "views" (html files in your case). I'll call it static for the example. Once it's done, add this line in your server code:

app.use("/static", express.static('./static/'));

This will effectively serve every file in your "static" folder via the /static route.

Querying your index.js file in the client thus becomes:

<script src="static/index.js"></script>

Only allow specific characters in textbox

You can probably use the KeyDown event, KeyPress event or KeyUp event. I would first try the KeyDown event I think.

You can set the Handled property of the event args to stop handling the event.

"call to undefined function" error when calling class method

you need to call the function like this


instead of just assign()

Better way to sort array in descending order

Depending on the sort order, you can do this :

    int[] array = new int[] { 3, 1, 4, 5, 2 };
                    new Comparison<int>(
                            (i1, i2) => i2.CompareTo(i1)

... or this :

    int[] array = new int[] { 3, 1, 4, 5, 2 };
                    new Comparison<int>(
                            (i1, i2) => i1.CompareTo(i2)

i1 and i2 are just reversed.

JavaScript string and number conversion

Simplest is when you want to make a integer a string do

var a,b, c;
a = 1;
b = a.toString(); // This will give you string

Now, from the variable b which is of type string we can get the integer

c = b *1; //This will give you integer value of number :-)

If you want to check above is a number. If you are not sure if b contains integer then you can use

if(isNaN(c*1)) {
  //NOt a number
else //number

Can I get div's background-image url?

I'm using this one

  function getBackgroundImageUrl($element) {
    if (!($element instanceof jQuery)) {
      $element = $($element);

    var imageUrl = $element.css('background-image');
    return imageUrl.replace(/(url\(|\)|'|")/gi, ''); // Strip everything but the url itself

SELECT from nothing?

I know this is an old question but the best workaround for your question is using a dummy subquery:

SELECT 'Hello World'
FROM (SELECT name='Nothing') n

This way you can have WHERE and any clause (like Joins or Apply, etc.) after the select statement since the dummy subquery forces the use of the FROM clause without changing the result.

Print to standard printer from Python?

To print to any printer on the network you can send a PJL/PCL print job directly to a network printer on port 9100.

Please have a look at the below link that should give a good start:

Also, If there is a way to call Windows cmd you can use FTP put to print your page on 9100. Below link should give you details, I have used this method for HP printers but I believe it will work for other printers.

How to use a switch case 'or' in PHP

switch ($value)
    case 1:
    case 2:
        echo "the value is either 1 or 2.";

This is called "falling through" the case block. The term exists in most languages implementing a switch statement.

Extract / Identify Tables from PDF python

I'd just like to add to the very helpful answer from Kurt Pfeifle - there is now a Python wrapper for Tabula, and this seems to work very well so far:

This will convert your PDF table to a Pandas data frame. You can also set the area in x,y co-ordinates which is obviously very handy for irregular data.

How to make two plots side-by-side using Python?

You can use - matplotlib.gridspec.GridSpec

Check -

The below code displays a heatmap on right and an Image on left.

#Creating 1 row and 2 columns grid
gs = gridspec.GridSpec(1, 2) 
fig = plt.figure(figsize=(25,3))

#Using the 1st row and 1st column for plotting heatmap

#Using the 1st row and 2nd column to show the image

#The below lines are used to display the image on ax1
image = io.imread("https://images-na.ssl-images-")


Output image

Insert data using Entity Framework model

It should be:



  1. TableName: the name of the table in the database.
  2. TableEntityInstance: an instance of the table entity class.

If your table is Orders, then:

Order order = new Order();

For example:

 var id = Guid.NewGuid();

 // insert
 using (var db = new EfContext("name=EfSample"))
    var customers = db.Set<Customer>();
    customers.Add( new Customer { CustomerId = id, Name = "John Doe" } );


Here is a live example:

public void UpdatePlayerScreen(byte[] imageBytes, string installationKey)
  var player = (from p in this.ObjectContext.Players where p.InstallationKey == installationKey select p).FirstOrDefault();

  var current = (from d in this.ObjectContext.Screenshots where d.PlayerID == player.ID select d).FirstOrDefault();

  if (current != null)
    current.Screen = imageBytes;
    current.Refreshed = DateTime.Now;

    Screenshot screenshot = new Screenshot();

    screenshot.ID = Guid.NewGuid();
    screenshot.Interval = 1000;
    screenshot.IsTurnedOn = true;
    screenshot.PlayerID = player.ID;
    screenshot.Refreshed = DateTime.Now;
    screenshot.Screen = imageBytes;


What is the best way to calculate a checksum for a file that is on my machine?

QuickHash an open source tool supporting MD5, SHA1, SHA256, SHA512 and available for the Linux, Windows, and Apple Mac.

How to create a thread?

The following ways work.

// The old way of using ParameterizedThreadStart. This requires a
// method which takes ONE object as the parameter so you need to
// encapsulate the parameters inside one object.
Thread t = new Thread(new ParameterizedThreadStart(StartupA));
t.Start(new MyThreadParams(path, port));

// You can also use an anonymous delegate to do this.
Thread t2 = new Thread(delegate()
    StartupB(port, path);

// Or lambda expressions if you are using C# 3.0
Thread t3 = new Thread(() => StartupB(port, path));

The Startup methods have following signature for these examples.

public void StartupA(object parameters);

public void StartupB(int port, string path);

Dynamic SELECT TOP @var In SQL Server

In x0n's example, it should be:


SELECT * from sometable


HTML5 Canvas Rotate Image

You can use canvas’ context.translate & context.rotate to do rotate your image

enter image description here

Here’s a function to draw an image that is rotated by the specified degrees:

function drawRotated(degrees){

    // save the unrotated context of the canvas so we can restore it later
    // the alternative is to untranslate & unrotate after drawing;

    // move to the center of the canvas

    // rotate the canvas to the specified degrees

    // draw the image
    // since the context is rotated, the image will be rotated also

    // we’re done with the rotating so restore the unrotated context

Here is code and a Fiddle:

<!doctype html>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src=""></script>

    body{ background-color: ivory; }
    canvas{border:1px solid red;}


    var canvas=document.getElementById("canvas");
    var ctx=canvas.getContext("2d");

    var angleInDegrees=0;

    var image=document.createElement("img");



    function drawRotated(degrees){

}); // end $(function(){});


    <canvas id="canvas" width=300 height=300></canvas><br>
    <button id="clockwise">Rotate right</button>
    <button id="counterclockwise">Rotate left</button>

XPath: How to select elements based on their value?

The condition below:

//Element[@attribute1="abc" and @attribute2="xyz" and Data]

checks for the existence of the element Data within Element and not for element value Data.

Instead you can use

//Element[@attribute1="abc" and @attribute2="xyz" and text()="Data"]

How do I get the domain originating the request in express.js?

Instead of:

var host = req.get('host');
var origin = req.get('origin');

you can also use:

var host =;
var origin = req.headers.origin;

Java ArrayList - Check if list is empty

You should use method listName.isEmpty()

How to view the stored procedure code in SQL Server Management Studio

You can view all the objects code stored in the database with this query:

    USE [test] --Database Name
SELECT'.' AS       [Object], 
     sys.objects AS ob
     LEFT JOIN sys.schemas AS sch ON
            sch.schema_id = ob.schema_id
     LEFT JOIN sys.sql_modules AS mod ON
            mod.object_id = ob.object_id
WHERE mod.definition IS NOT NULL --Selects only objects with the definition (code)

Can I force a page break in HTML printing?

I needed a page break after every 3rd row while we use print command on browser.

I added

<div style='page-break-before: always;'></div>

after every 3rd row and my parent div have display: flex; so I removed display: flex; and it was working as I want.

Install Chrome extension form outside the Chrome Web Store

For Windows, you can also whitelist your extension through Windows policies. The full steps are details in this answer, but there are quicker steps:

  1. Create the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallWhitelist.
  2. For each extension you want to whitelist, add a string value whose name should be a sequence number (starting at 1) and value is the extension ID.

For instance, in order to whitelist 2 extensions with ID aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa and bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb, create a string value with name 1 and value aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, and a second value with name 2 and value bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb. This can be sum up by this registry file:

Windows Registry Editor Version 5.00



EDIT: actually, Chromium docs also indicate how to do it for other OS.

How do I Geocode 20 addresses without receiving an OVER_QUERY_LIMIT response?

Unfortunately this is a restriction of the Google maps service.

I am currently working on an application using the geocoding feature, and I'm saving each unique address on a per-user basis. I generate the address information (city, street, state, etc) based on the information returned by Google maps, and then save the lat/long information in the database as well. This prevents you from having to re-code things, and gives you nicely formatted addresses.

Another reason you want to do this is because there is a daily limit on the number of addresses that can be geocoded from a particular IP address. You don't want your application to fail for a person for that reason.

What are the most-used vim commands/keypresses?

Have you run through Vim's built-in tutorial? If not, drop to the command-line and type vimtutor. It's a great way to learn the initial commands.

Vim has an incredible amount of flexibility and power and, if you're like most vim users, you'll learn a lot of new commands and forget old ones, then relearn them. The built-in help is good and worthy of periodic browsing to learn new stuff.

There are several good FAQs and cheatsheets for vim on the internet. I'd recommend searching for vim + faq and vim + cheatsheet. is a good source, as is Vim Tips wiki.

How to connect Android app to MySQL database?

The one way is by using webservice, simply write a webservice method in PHP or any other language . And From your android app by using http client request and response , you can hit the web service method which will return whatever you want.

For PHP You can create a webservice like this. Assuming below we have a php file in the server. And the route of the file is

       case 'userlogin':
           //perform your userlogin task here

Now you can use Volley or Retrofit to send a network request to the above PHP Script and then, actually the php script will handle the database operation.

In this case the PHP script is called a RESTful API.

You can learn all the operation at MySQL from this tutorial. Android MySQL Tutorial to Perform CRUD.

How do I change tab size in Vim?

Several of the answers on this page are 'single use' fixes to the described problem. Meaning, the next time you open a document with vim, the previous tab settings will return.

If anyone is interested in permanently changing the tab settings:

How do I check if a string contains another string in Swift?

> IN SWIFT 3.0

let str = "Hello Swift"
if str.lowercased().contains("Swift".lowercased()) {
    print("String Contains Another String")
} else {
    print("Not Exists")


String Contains Another String

How do you connect to multiple MySQL databases on a single webpage?

Unless you really need to have more than one instance of a PDO object in play, consider the following:

$con = new PDO('mysql:host=localhost', $username, $password, 
      array(PDO::ATTR_PERSISTENT => true));

Notice the absence of dbname= in the construction arguments.

When you connect to MySQL via a terminal or other tool, the database name is not needed off the bat. You can switch between databases by using the USE dbname statement via the PDO::exec() method.

$con->exec("USE someDatabase");
$con->exec("USE anotherDatabase");

Of course you may want to wrap this in a catch try statement.

How to update the constant height constraint of a UIView programmatically?

To update a layout constraint you only need to update the constant property and call layoutIfNeeded after.

myConstraint.constant = newValue

Use jquery to set value of div tag

try this function $('').text('test');

datetime datatype in java

java.util.Date represents an instant in time, with no reference to a particular time zone or calendar system. It does hold both date and time though - it's basically a number of milliseconds since the Unix epoch.

Alternatively you can use java.util.Calendar which does know about both of those things.

Personally I would strongly recommend you use Joda Time which is a much richer date/time API. It allows you to express your data much more clearly, with types for "just dates", "just local times", "local date/time", "instant", "date/time with time zone" etc. Most of the types are also immutable, which is a huge benefit in terms of code clarity.

How to get a reference to an iframe's window object inside iframe's onload handler created from parent window

You're declaring everything in the parent page. So the references to window and document are to the parent page's. If you want to do stuff to the iframe's, use iframe || iframe.contentWindow to access its window, and iframe.contentDocument || iframe.contentWindow.document to access its document.

There's a word for what's happening, possibly "lexical scope": What is lexical scope?

The only context of a scope is this. And in your example, the owner of the method is doc, which is the iframe's document. Other than that, anything that's accessed in this function that uses known objects are the parent's (if not declared in the function). It would be a different story if the function were declared in a different place, but it's declared in the parent page.

This is how I would write it:

(function () {
  var dom, win, doc, where, iframe;

  iframe = document.createElement('iframe');
  iframe.src = "javascript:false";

  where = document.getElementsByTagName('script')[0];
  where.parentNode.insertBefore(iframe, where);

  win = iframe.contentWindow || iframe;
  doc = iframe.contentDocument || iframe.contentWindow.document;;
  doc._l = (function (w, d) {
    return function () {
      w.vanishing_global = new Date().getTime();

      var js = d.createElement("script");
      js.src = 'test-vanishing-global.js?' + w.vanishing_global; = "foobar";
      d.foobar = "foobar:" + Math.random();
      d.foobar = "barfoo:" + Math.random();
  })(win, doc);
  doc.write('<body onload="document._l();"></body>');

The aliasing of win and doc as w and d aren't necessary, it just might make it less confusing because of the misunderstanding of scopes. This way, they are parameters and you have to reference them to access the iframe's stuff. If you want to access the parent's, you still use window and document.

I'm not sure what the implications are of adding methods to a document (doc in this case), but it might make more sense to set the _l method on win. That way, things can be run without a prefix...such as <body onload="_l();"></body>

SQL Server 2008 R2 can't connect to local database in Management Studio

I have the same error but with different case. Let me quote the solution from here:

Luckly I also have the same set up on my desktop. I have installed first default instance and then Sql Express. Everything is fine for me for several days. Then I tried connecting the way you trying, i.e with MachineName\MsSqlServer to default instance and I got exctaly the same error.

So the solution is when you trying to connect to default instance you don't need to provide instance name.(well this is something puzzled me, why it is failing when we are giving instance name when it is a default instance? Is it some bug, don't know)

Just try with - PC-NAME and everything will be fine. PC-NAME is the MSSQLServer instance.

Edit : Well after reading your question again I realized that you are not aware of the fact that MSSQLSERVER is the default instance of Sql Server. And for connecting to default instance (MSSQLSERVER) you don't need to provide the instance name in connection string. The "MachineName" is itself means "MachineName\MSSQLSERVER".

A simple scenario using wait() and notify() in java

The wait() and notify() methods are designed to provide a mechanism to allow a thread to block until a specific condition is met. For this I assume you're wanting to write a blocking queue implementation, where you have some fixed size backing-store of elements.

The first thing you have to do is to identify the conditions that you want the methods to wait for. In this case, you will want the put() method to block until there is free space in the store, and you will want the take() method to block until there is some element to return.

public class BlockingQueue<T> {

    private Queue<T> queue = new LinkedList<T>();
    private int capacity;

    public BlockingQueue(int capacity) {
        this.capacity = capacity;

    public synchronized void put(T element) throws InterruptedException {
        while(queue.size() == capacity) {

        notify(); // notifyAll() for multiple producer/consumer threads

    public synchronized T take() throws InterruptedException {
        while(queue.isEmpty()) {

        T item = queue.remove();
        notify(); // notifyAll() for multiple producer/consumer threads
        return item;

There are a few things to note about the way in which you must use the wait and notify mechanisms.

Firstly, you need to ensure that any calls to wait() or notify() are within a synchronized region of code (with the wait() and notify() calls being synchronized on the same object). The reason for this (other than the standard thread safety concerns) is due to something known as a missed signal.

An example of this, is that a thread may call put() when the queue happens to be full, it then checks the condition, sees that the queue is full, however before it can block another thread is scheduled. This second thread then take()'s an element from the queue, and notifies the waiting threads that the queue is no longer full. Because the first thread has already checked the condition however, it will simply call wait() after being re-scheduled, even though it could make progress.

By synchronizing on a shared object, you can ensure that this problem does not occur, as the second thread's take() call will not be able to make progress until the first thread has actually blocked.

Secondly, you need to put the condition you are checking in a while loop, rather than an if statement, due to a problem known as spurious wake-ups. This is where a waiting thread can sometimes be re-activated without notify() being called. Putting this check in a while loop will ensure that if a spurious wake-up occurs, the condition will be re-checked, and the thread will call wait() again.

As some of the other answers have mentioned, Java 1.5 introduced a new concurrency library (in the java.util.concurrent package) which was designed to provide a higher level abstraction over the wait/notify mechanism. Using these new features, you could rewrite the original example like so:

public class BlockingQueue<T> {

    private Queue<T> queue = new LinkedList<T>();
    private int capacity;
    private Lock lock = new ReentrantLock();
    private Condition notFull = lock.newCondition();
    private Condition notEmpty = lock.newCondition();

    public BlockingQueue(int capacity) {
        this.capacity = capacity;

    public void put(T element) throws InterruptedException {
        try {
            while(queue.size() == capacity) {

        } finally {

    public T take() throws InterruptedException {
        try {
            while(queue.isEmpty()) {

            T item = queue.remove();
            return item;
        } finally {

Of course if you actually need a blocking queue, then you should use an implementation of the BlockingQueue interface.

Also, for stuff like this I'd highly recommend Java Concurrency in Practice, as it covers everything you could want to know about concurrency related problems and solutions.

How do I find out what License has been applied to my SQL Server installation?

I know this post is older, but haven't seen a solution that provides the actual information, so I want to share what I use for SQL Server 2012 and above. the link below leads to the screenshot showing the information.

First (so no time is wasted):

SQL Server 2000:

SQL Server 2005+

The "SELECT SERVERPROPERTY('LicenseType'), SERVERPROPERTY('NumLicenses')" is not in use anymore. You can see more details on MSFT documentation:

SQL Server 2005 - 2008R2 you would have to:

Using PowerShell:

Using TSQL (you would need to know the registry key path off hand):

SQL Server 2012+

Now, you can extract SQL Server Licensing information from the SQL Server Error Log, granted it may not be formatted the way you want, but the information is there and can be parsed, along with more descriptive information that you probably didn't expect.

EXEC sp_readerrorlog @p1 = 0
                    ,@p2 = 1
                    ,@p3 = N'licensing'

NOTE: I tried pasting the image directly, but since I am new at stakoverflow we have to follow the link below.

SQL Server License information via sp_readerrorlog

How to convert List to Json in Java

download java-json.jar from Java2s then use the JSONArray constructor

List myList = new ArrayList<>();    
JSONArray jsonArray = new JSONArray(myList);

How to reset the use/password of jenkins on windows?

I had the same problem, no possible connection at second login.

After solving the problem (useSecurity, etc., see above), I realized that admin/admin worked (with Synology, it that's relevant).

How to use ArrayList.addAll()?

May be this helps

List<String> l = Arrays.asList("+","-");

How can I confirm a database is Oracle & what version it is using SQL?

This will work starting from Oracle 10

select version
      , regexp_substr(banner, '[^[:space:]]+', 1, 4) as edition 
from    v$instance
     ,  v$version where regexp_like(banner, 'edition', 'i');

how to find 2d array size in c++

Along with the _countof() macro you can refer to the array size using pointer notation, where the array name by itself refers to the row, the indirection operator appended by the array name refers to the column.

#include <iostream>
#include <iomanip>

using namespace std;

int main()
    int beans[3][4]{
        { 1, 2, 3, 4 }, 
        { 5, 6, 7, 8 }, 
        { 9, 10, 11, 12 }

    cout << "Row size = " << _countof(beans)  // Output row size
        << "\nColumn size = " << _countof(*beans);  // Output column size
    cout << endl;

    // Used in a for loop with a pointer.

    int(*pbeans)[4]{ beans };

    for (int i{}; i < _countof(beans); ++i) {

        cout << endl;

        for (int j{}; j < _countof(*beans); ++j) {

            cout << setw(4) << pbeans[i][j];

    cout << endl;

Project Links do not work on Wamp Server

Re: Wampserver LocalHost links not working correctly
This is as of June 2014 with Wampserver2.5 (maybe they'll fix this in later builds).
Note: to use LocalHost:8080 instead of LocalHost just make the appropriate changes in the edits mentioned below.

There are 2 aspects of this issue -
The first is to be able to access items under "Your Projects" from the Wamp localhost homepage.
The second is to be able to correctly access items listed in the Wampserver Icon Taskbar's "My Projects" list.

To fix the first (to be able to access items under "Your Projects" from the Wamp localhost homepage) you will need to do the following...

There are 2 edits that you must make in the index.php file located in your wamp\www folder (usually C:\wamp\www)

1) on Line 30 change

  $suppress_localhost = true;


  $suppress_localhost = false;

2) on line 338 change

  $projectContents .= '<li><a href="'.($suppress_localhost ? 'http://' : '').$file.'">'.$file.'</a></li>';


  $projectContents .= '<li><a href="'.($suppress_localhost ? 'http://' : 'http://localhost//').$file.'">'.$file.'</a></li>';

After you've made the above edits - if the Wampserver is running just refresh the local host page and the changes become immediately effective.

To fix the 2nd item (the Wampserver Icon Taskbar's "My Projects" list): You need to edit C:\wamp\scripts\refresh.php

Locate line 651 and change the section of the line that reads

   Parameters: "http://'.$projectContents[$i].'/"; Glyph: 5


   Parameters: "http://localhost//'.$projectContents[$i].'/"; Glyph: 5

After you make these 2nd set of changes you may have to force Wampserver to refresh the "My Projects" list by toggling the Put Online/Offline option at the bottom of the Wamp Icon Tray App.

How to get PID of process by specifying process name and store it in a variable to use further?

If you want to kill -9 based on a string (you might want to try kill first) you can do something like this:

ps axf | grep <process name> | grep -v grep | awk '{print "kill -9 " $1}'

This will show you what you're about to kill (very, very important) and just pipe it to sh when the time comes to execute:

ps axf | grep <process name> | grep -v grep | awk '{print "kill -9 " $1}' | sh

New og:image size for Facebook share? og:image is 325x325 (1:1 aspect ratio, square)

How to submit a form with JavaScript by clicking a link?

You could give the form and the link some ids and then subscribe for the onclick event of the link and submit the form:

<form id="myform" action="" method="POST">
    <a href="#" id="mylink"> submit </a>

and then:

window.onload = function() {
    document.getElementById('mylink').onclick = function() {
        return false;

I would recommend you using a submit button for submitting forms as it respects the markup semantics and it will work even for users with javascript disabled.

Ship an application with a database

My solution neither uses any third-party library nor forces you to call custom methods on SQLiteOpenHelper subclass to initialize the database on creation. It also takes care of database upgrades as well. All that needs to be done is to subclass SQLiteOpenHelper.


  1. The database that you wish to ship with the app. It should contain a 1x1 table named android_metadata with an attribute locale having the value en_US in addition to the tables unique to your app.

Subclassing SQLiteOpenHelper:

  1. Subclass SQLiteOpenHelper.
  2. Create a private method within the SQLiteOpenHelper subclass. This method contains the logic to copy database contents from the database file in the 'assets' folder to the database created in the application package context.
  3. Override onCreate, onUpgrade and onOpen methods of SQLiteOpenHelper.

Enough said. Here goes the SQLiteOpenHelper subclass:

public class PlanDetailsSQLiteOpenHelper extends SQLiteOpenHelper {
    private static final String TAG = "SQLiteOpenHelper";

    private final Context context;
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "my_custom_db";

    private boolean createDb = false, upgradeDb = false;

    public PlanDetailsSQLiteOpenHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;

     * Copy packaged database from assets folder to the database created in the
     * application package context.
     * @param db
     *            The target database in the application package context.
    private void copyDatabaseFromAssets(SQLiteDatabase db) {
        Log.i(TAG, "copyDatabase");
        InputStream myInput = null;
        OutputStream myOutput = null;
        try {
            // Open db packaged as asset as the input stream
            myInput = context.getAssets().open("path/to/shipped/db/file");

            // Open the db in the application package context:
            myOutput = new FileOutputStream(db.getPath());

            // Transfer db file contents:
            byte[] buffer = new byte[1024];
            int length;
            while ((length = > 0) {
                myOutput.write(buffer, 0, length);

            // Set the version of the copied database to the current
            // version:
            SQLiteDatabase copiedDb = context.openOrCreateDatabase(
                DATABASE_NAME, 0, null);
            copiedDb.execSQL("PRAGMA user_version = " + DATABASE_VERSION);

        } catch (IOException e) {
            throw new Error(TAG + " Error copying database");
        } finally {
            // Close the streams
            try {
                if (myOutput != null) {
                if (myInput != null) {
            } catch (IOException e) {
                throw new Error(TAG + " Error closing streams");

    public void onCreate(SQLiteDatabase db) {
        Log.i(TAG, "onCreate db");
        createDb = true;

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.i(TAG, "onUpgrade db");
        upgradeDb = true;

    public void onOpen(SQLiteDatabase db) {
        Log.i(TAG, "onOpen db");
        if (createDb) {// The db in the application package
            // context is being created.
            // So copy the contents from the db
            // file packaged in the assets
            // folder:
            createDb = false;

        if (upgradeDb) {// The db in the application package
            // context is being upgraded from a lower to a higher version.
            upgradeDb = false;
            // Your db upgrade logic here:

Finally, to get a database connection, just call getReadableDatabase() or getWritableDatabase() on the SQLiteOpenHelper subclass and it will take care of creating a db, copying db contents from the specified file in the 'assets' folder, if the database does not exist.

In short, you can use the SQLiteOpenHelper subclass to access the db shipped in the assets folder just as you would use for a database that is initialized using SQL queries in the onCreate() method.

What is the best way to tell if a character is a letter or number in Java without using regexes?

As the answers indicate (if you examine them carefully!), your question is ambiguous. What do you mean by "an A-z letter" or a digit?

  • If you want to know if a character is a Unicode letter or digit, then use the Character.isLetter and Character.isDigit methods.

  • If you want to know if a character is an ASCII letter or digit, then the best thing to do is to test by comparing with the character ranges 'a' to 'z', 'A' to 'Z' and '0' to '9'.

Note that all ASCII letters / digits are Unicode letters / digits ... but there are many Unicode letters / digits characters that are not ASCII. For example, accented letters, cyrillic, sanskrit, ...

The general solution is to do this:

Character.UnicodeBlock block = Character.UnicodeBlock.of(someCodePoint);

and then test to see if the block is one of the ones that you are interested in. In some cases you will need to test for multiple blocks. For example, there are (at least) 4 code blocks for Cyrillic characters and 7 for Latin. The Character.UnicodeBlock class defines static constants for well-known blocks; see the javadocs.

Note that any code point will be in at most one block.

Resize iframe height according to content height in it

To directly answer your two subquestions: No, you cannot do this with Ajax, nor can you calculate it with PHP.

What I have done in the past is use a trigger from the iframe'd page in window.onload (NOT domready, as it can take a while for images to load) to pass the page's body height to the parent.

<body onload='parent.resizeIframe(document.body.scrollHeight)'>

Then the parent.resizeIframe looks like this:

function resizeIframe(newHeight)
    document.getElementById('blogIframe').style.height = parseInt(newHeight,10) + 10 + 'px';

Et voila, you have a robust resizer that triggers once the page is fully rendered with no nasty contentdocument vs contentWindow fiddling :)

Sure, now people will see your iframe at default height first, but this can be easily handled by hiding your iframe at first and just showing a 'loading' image. Then, when the resizeIframe function kicks in, put two extra lines in there that will hide the loading image, and show the iframe for that faux Ajax look.

Of course, this only works from the same domain, so you may want to have a proxy PHP script to embed this stuff, and once you go there, you might as well just embed your blog's RSS feed directly into your site with PHP.

How to install Openpyxl with pip

  1. go to command prompt, and run as Administrator
  2. in c:/> prompt -> pip install openpyxl
  3. once you run in CMD you will get message like, Successfully installed et-xmlfile-1.0.1 jdcal-1.4.1 openpyxl-3.0.5
  4. go to python interactive shell and run openpyxl module
  5. openpyxl will work

How to replace sql field value

It depends on what you need to do. You can use replace since you want to replace the value:

select replace(email, '.com', '.org')
from yourtable

Then to UPDATE your table with the new ending, then you would use:

update yourtable
set email = replace(email, '.com', '.org')

You can also expand on this by checking the last 4 characters of the email value:

update yourtable
set email = replace(email, '.com', '.org')
where right(email, 4) = '.com'

However, the issue with replace() is that .com can be will in other locations in the email not just the last one. So you might want to use substring() the following way:

update yourtable
set email = substring(email, 1, len(email) -4)+'.org'
where right(email, 4) = '.com';

See SQL Fiddle with Demo

Using substring() will return the start of the email value, without the final .com and then you concatenate the .org to the end. This prevents the replacement of .com elsewhere in the string.

Alternatively you could use stuff(), which allows you to do both deleting and inserting at the same time:

update yourtable
set email = stuff(email, len(email) - 3, 4, '.org')
where right(email, 4) = '.com';

This will delete 4 characters at the position of the third character before the last one (which is the starting position of the final .com) and insert .org instead.

See SQL Fiddle with Demo for this method as well.

Get list of databases from SQL Server

I use the following SQL Server Management Objects code to get a list of databases that aren't system databases and aren't snapshots.

using Microsoft.SqlServer.Management.Smo;

public static string[] GetDatabaseNames( string serverName )
   var server = new Server( serverName );
   return ( from Database database in server.Databases 
            where !database.IsSystemObject && !database.IsDatabaseSnapshot
            select database.Name 

How to export MySQL database with triggers and procedures?

I've created the following script and it worked for me just fine.

#! /bin/sh
cd $(dirname $0)
FILE=$DB-$(date +%F).sql
mysqldump --routines "--user=${DBUSER}"  --password=$DBPASSWD $DB > $PWD/$FILE
gzip $FILE
echo Created $PWD/$FILE*

and you call the script using command line arguments. my_db dev_user dev_password

Most efficient way to check if a file is empty in Java on Windows

Now both these methods fail at times when the log file is empty (has no content), yet the file size is not zero (2 bytes).

Actually, I think you will find that the file is NOT empty. Rather I think that you will find that those two characters are a CR and a NL; i.e. the file consists of one line that is empty.

If you want to test if a file is either empty or has a single empty line then a simple, relatively efficient way is:

try (BufferedReader br = new BufferedReader(FileReader(fileName))) {
    String line = br.readLine();
    if (line == null || 
        (line.length() == 0 && br.readLine() == null)) {
        System.out.println("NO ERRORS!");
    } else {
        System.out.println("SOME ERRORS!");

Can we do this more efficiently? Possibly. It depends on how often you have to deal with the three different cases:

  • a completely empty file
  • a file consisting of a single empty line
  • a file with a non-empty line, or multiple lines.

You can probably do better by using Files.length() and / or reading just the first two bytes. However, the problems include:

  • If you both test the file size AND read the first few bytes then you are making 2 syscalls.
  • The actual line termination sequence could be CR, NL or CR NL, depending on the platform. (I know you say this is for Windows, but what happens if you need to port your application? Or if someone sends you a non-Windows file?)
  • It would be nice to avoid setting up stream / reader stack, but the file's character encoding could map CR and NL to something other than the bytes 0x0d and 0x0a. (For example ... UTF-16)
  • Then there's the annoying habit of some Windows utilities have putting BOM markers into UTF-8 encoded files. (This would even mess up the simple version above!)

All of this means that the most efficient possible solution is going to be rather complicated.

Add Expires headers

The easiest way to add these headers is a .htaccess file that adds some configuration to your server. If the assets are hosted on a server that you don't control, there's nothing you can do about it.

Note that some hosting providers will not let you use .htaccess files, so check their terms if it doesn't seem to work.

The HTML5Boilerplate project has an excellent .htaccess file that covers the necessary settings. See the relevant part of the file at their Github repository

These are the important bits

# ----------------------------------------------------------------------
# Expires headers (for better cache control)
# ----------------------------------------------------------------------

# These are pretty far-future expires headers.
# They assume you control versioning with filename-based cache busting
# Additionally, consider that outdated proxies may miscache

# If you don't use filenames to version, lower the CSS and JS to something like
# "access plus 1 week".

<IfModule mod_expires.c>
  ExpiresActive on

# Your document html
  ExpiresByType text/html "access plus 0 seconds"

# Media: images, video, audio
  ExpiresByType audio/ogg "access plus 1 month"
  ExpiresByType image/gif "access plus 1 month"
  ExpiresByType image/jpeg "access plus 1 month"
  ExpiresByType image/png "access plus 1 month"
  ExpiresByType video/mp4 "access plus 1 month"
  ExpiresByType video/ogg "access plus 1 month"
  ExpiresByType video/webm "access plus 1 month"

# CSS and JavaScript
  ExpiresByType application/javascript "access plus 1 year"
  ExpiresByType text/css "access plus 1 year"

They have documented what that file does, the most important bit is that you need to rename your CSS and Javascript files whenever they change, because your visitor's browsers will not check them again for a year, once they are cached.

Add Favicon to Website

  1. This is not done in PHP. It's part of the <head> tags in a HTML page.
  2. That icon is called a favicon. According to Wikipedia:

    A favicon (short for favorites icon), also known as a shortcut icon, website icon, URL icon, or bookmark icon is a 16×16 or 32×32 pixel square icon associated with a particular website or webpage.

  3. Adding it is easy. Just add an .ico image file that is either 16x16 pixels or 32x32 pixels. Then, in the web pages, add <link rel="shortcut icon" href="favicon.ico" type="image/x-icon"> to the <head> element.
  4. You can easily generate favicons here.

Common MySQL fields and their appropriate data types

Here are some common datatypes I use (I am not much of a pro though):

| Column           | Data type     | Note
| ---------------- | ------------- | -------------------------------------
| id               | INTEGER       | AUTO_INCREMENT, UNSIGNED                                                          |  
| uuid             | CHAR(36)      | or CHAR(16) binary                                                                |  
| title            | VARCHAR(255)  |                                                                                   |  
| full name        | VARCHAR(70)   |                                                                                   |  
| gender           | TINYINT       | UNSIGNED                                                                          |  
| description      | TINYTEXT      | often may not be enough, use TEXT 
| post body        | TEXT          |                                                                                   |  
| email            | VARCHAR(255)  |                                                                                   |  
| url              | VARCHAR(2083) | MySQL version < 5.0.3 - use TEXT                                                  |  
| salt             | CHAR(x)       | randomly generated string, usually of 
                                     fixed length (x)    
| digest (md5)     | CHAR(32)      |                                                                                   |  
| phone number     | VARCHAR(20)   |                                                                                   |  
| US zip code      | CHAR(5)       | Use CHAR(10) if you store extended 
| US/Canada p.code | CHAR(6)       |                                                                                   |  
| file path        | VARCHAR(255)  |                                                                                   |  
| 5-star rating    | DECIMAL(3,2)  | UNSIGNED                                                                          |  
| price            | DECIMAL(10,2) | UNSIGNED                                                                          |  
| date (creation)  | DATE/DATETIME | usually displayed as initial date of 
                                     a post                                       |  
| date (tracking)  | TIMESTAMP     | can be used for tracking changes in a 
                                     post                                        |  
| tags, categories | TINYTEXT      | comma separated values *                                                          |  
| status           | TINYINT(1)    | 1 – published, 0 – unpublished, … You 
                                     can also use ENUM for human-readable 
| json data        | JSON          | or LONGTEXT       

addEventListener in Internet Explorer

addEventListener is supported from version 9 onwards; for older versions use the somewhat similar attachEvent function.

How to close an iframe within iframe itself

function closeWin()   // Tested Code
var someIframe = window.parent.document.getElementById('iframe_callback');

<input class="question" name="Close" type="button" value="Close" onClick="closeWin()" tabindex="10" /> 

Kill detached screen session

[xxx@devxxx ~]$ screen -ls

There are screens on:
        23487.pts-0.devxxx      (Detached)
        26727.pts-0.devxxx      (Attached)
2 Sockets in /tmp/uscreens/S-xxx.

[xxx@devxxx ~]$ screen -X -S 23487.pts-0.devxxx kill

[xxx@devxxx ~]$ screen -ls
There is a screen on:
        26727.pts-0.devxxx      (Attached)
1 Socket in /tmp/uscreens/S-xxx.

How do I format a number with commas in T-SQL?

While I agree with everyone, including the OP, who says that formatting should be done in the presentation layer, this formatting can be accomplished in T-SQL by casting to money and then converting to varchar. This does include trailing decimals, though, that could be looped off with SUBSTRING.

SELECT CONVERT(varchar, CAST(987654321 AS money), 1)

Android XML Percent Symbol

Not exactly your problem but a similar one.

If you have more than one formatting in your string entry, you should not use "%s" multiple times.


<string name="entry">Planned time %s - %s (%s)</string>

DO :

<string name="entry">Planned time %1$s - %2$s (%3$s)</string>

How to format a numeric column as phone number in SQL

Updated @sqiller's function for my purposes

CREATE FUNCTION [toolbox].[FormatPhoneNumber] (
    @PhoneNumber VARCHAR(50),
    @DefaultIfUnknown VARCHAR(50)
    -- remove any extension
    IF CHARINDEX('x', @PhoneNumber, 1) > 0
        SET @PhoneNumber = SUBSTRING(@PhoneNumber, 1, CHARINDEX('x', @PhoneNumber, 1) - 1)

    -- cleanse phone number string
    WHILE PATINDEX('%[^0-9]%',@PhoneNumber) > 0
        SET @PhoneNumber = REPLACE(@PhoneNumber,

    -- Remove US international code if exists, i.e. 12345678900
    IF SUBSTRING(@PhoneNumber,1,1) = '1' AND LEN(@PhoneNumber) = 11
        SET @PhoneNumber = SUBSTRING(@PhoneNumber, 2, 10)

    -- any phone numbers without 10 characters are set to default
    IF LEN(@PhoneNumber) <> 10
        RETURN @DefaultIfUnknown

    -- build US standard phone number
    SET @PhoneNumber = '(' + SUBSTRING(@PhoneNumber,1,3) + ') ' +
                SUBSTRING(@PhoneNumber,4,3) + '-' + SUBSTRING(@PhoneNumber,7,4)

    RETURN @PhoneNumber

Removing display of row names from data frame

If you want to format your table via kable, you can use row.names = F

kable(df, row.names = F)

Setting max-height for table cell contents

Possibly not cross browser but I managed get this:

basically it requires a fixed height header and footer. and it absolute positions the table.

    table {
        width: 50%;
        height: 50%;
        border-spacing: 0;
    td {
        border: 1px solid black;
    #content {
        overflow: hidden;

javascript, is there an isObject function like isArray?

use the following

It will return a true or false

theObject instanceof Object

C# Linq Group By on multiple columns

Given a list:

var list = new List<Child>()
    new Child()
        {School = "School1", FavoriteColor = "blue", Friend = "Bob", Name = "John"},
    new Child()
        {School = "School2", FavoriteColor = "blue", Friend = "Bob", Name = "Pete"},
    new Child()
        {School = "School1", FavoriteColor = "blue", Friend = "Bob", Name = "Fred"},
    new Child()
        {School = "School2", FavoriteColor = "blue", Friend = "Fred", Name = "Bob"},

The query would look like:

var newList = list
    .GroupBy(x => new {x.School, x.Friend, x.FavoriteColor})
    .Select(y => new ConsolidatedChild()
            FavoriteColor = y.Key.FavoriteColor,
            Friend = y.Key.Friend,
            School = y.Key.School,
            Children = y.ToList()

Test code:

foreach(var item in newList)
    Console.WriteLine("School: {0} FavouriteColor: {1} Friend: {2}", item.School,item.FavoriteColor,item.Friend);
    foreach(var child in item.Children)
        Console.WriteLine("\t Name: {0}", child.Name);


School: School1 FavouriteColor: blue Friend: Bob
    Name: John
    Name: Fred
School: School2 FavouriteColor: blue Friend: Bob
    Name: Pete
School: School2 FavouriteColor: blue Friend: Fred
    Name: Bob

Android: How to add R.raw to project?

(With reference to Android Studio)

Create a new directory in res folder. Make sure to create new "Android Resource Directory" and not new "Directory".

Then ensure that there is at least one valid file in it. It should show up now.

JavaScript getElementByID() not working

You need to put the JavaScript at the end of the body tag.

It doesn't find it because it's not in the DOM yet!

You can also wrap it in the onload event handler like this:

window.onload = function() {
var refButton = document.getElementById( 'btnButton' );
refButton.onclick = function() {
   alert( 'I am clicked!' );

Validate email address textbox using JavaScript

This is quite an old question so I've updated this answer to take the HTML 5 email type into account.

You don't actually need JavaScript for this at all with HTML 5; just use the email input type:

<input type="email" />
  • If you want to make it mandatory, you can add the required parameter.

  • If you want to add additional RegEx validation (limit to email addresses for example), you can use the pattern parameter, e.g.:

    <input type="email" pattern="[email protected]" />

There's more information available on MozDev.

Original answer follows

First off - I'd recommend the email validator RegEx from Hexillion:

It's pretty comprehensive - :


I think you want a function in your JavaScript like:

function validateEmail(sEmail) {
  var reEmail = /^(?:[\w\!\#\$\%\&\'\*\+\-\/\=\?\^\`\{\|\}\~]+\.)*[\w\!\#\$\%\&\'\*\+\-\/\=\?\^\`\{\|\}\~]+@(?:(?:(?:[a-zA-Z0-9](?:[a-zA-Z0-9\-](?!\.)){0,61}[a-zA-Z0-9]?\.)+[a-zA-Z0-9](?:[a-zA-Z0-9\-](?!$)){0,61}[a-zA-Z0-9]?)|(?:\[(?:(?:[01]?\d{1,2}|2[0-4]\d|25[0-5])\.){3}(?:[01]?\d{1,2}|2[0-4]\d|25[0-5])\]))$/;

  if(!sEmail.match(reEmail)) {
    alert("Invalid email address");
    return false;

  return true;


In the HTML input you need to trigger the event with an onblur - the easy way to do this is to simply add something like:

<input type="text" name="email" onblur="validateEmail(this.value);" />

Of course that's lacking some sanity checks and won't do domain verification (that has to be done server side) - but it should give you a pretty solid JS email format verifier.

Note: I tend to use the match() string method rather than the test() RegExp method but it shouldn't make any difference.

"java.lang.OutOfMemoryError: PermGen space" in Maven build

I have found a solution of git bash command when you try to build war using git mvn clean install for “java.lang.OutOfMemoryError: PermGen space” in Maven build error come

use below command first 

$ export MAVEN_OPTS="-Xmx512m -Xss32m"

then use your mvn command to clean install /build war file

$ mvn clean install

NOTE: you don't need -XX:MaxPermSize argument in MAVEN_OPTS when your are using jdk1.8
Java HotSpot(TM) Client VM warning: ignoring option MaxPermSize=XXXm; support was removed in 8.0

How can I connect to MySQL on a WAMP server?

Change localhost:8080 to localhost:3306.

Refreshing page on click of a button

<button onclick=location=URL>Refresh</button>

Small hack.

PHP Get name of current directory

$myVar = str_replace('/', '', $_SERVER[REQUEST_URI]);

Result: images

Format timedelta to string

He already has a timedelta object so why not use its built-in method total_seconds() to convert it to seconds, then use divmod() to get hours and minutes?

hours, remainder = divmod(myTimeDelta.total_seconds(), 3600)
minutes, seconds = divmod(remainder, 60)

# Formatted only for hours and minutes as requested
print '%s:%s' % (hours, minutes)

This works regardless if the time delta has even days or years.

display:inline vs display:block

Block Elements: Elements liked div, p, headings are block level. They start from new line and occupy full width of parent element. Inline Elements: Elements liked b, i, span, img are inline level. They never start from new line and occupy width of content.

Python string prints as [u'String']

Maybe i dont understand , why cant you just get the element.text and then convert it before using it ? for instance (dont know why you would do this but...) find all label elements of the web page and iterate between them until you find one called MyText

        avail = []
        avail = driver.find_elements_by_class_name("label");
        for i in avail:
                if  i.text == "MyText":

Convert the string from i and do whatever you wanted to do ... maybe im missing something in the original message ? or was this what you were looking for ?

How to remove a web site from google analytics

Feb 2016 version: Admin tab, then select Property in the middle column, click Property Settings, then the Move To Trash Can button at the top right. No need to delete individual views.

Call to getLayoutInflater() in places not in activity

You can use this outside activities - all you need is to provide a Context:

LayoutInflater inflater = (LayoutInflater) context.getSystemService( Context.LAYOUT_INFLATER_SERVICE );

Then to retrieve your different widgets, you inflate a layout:

View view = inflater.inflate( R.layout.myNewInflatedLayout, null );
Button myButton = (Button) view.findViewById( );

EDIT as of July 2014

Davide's answer on how to get the LayoutInflater is actually more correct than mine (which is still valid though).

How to increase the distance between table columns in HTML?

A better solution than selected answer would be to use border-size rather than border-spacing. The main problem with using border-spacing is that even the first column would have a spacing in the front.

For example,

table {_x000D_
  border-collapse: separate;_x000D_
  border-spacing: 80px 0;_x000D_
td {_x000D_
  padding: 10px 0;_x000D_
    <td>First Column</td>_x000D_
    <td>Second Column</td>_x000D_
    <td>Third Column</td>_x000D_

To avoid this use: border-left: 100px solid #FFF; and set border:0px for the first column.

For example,

  border-left: 100px solid #FFF;_x000D_
 tr>td:first-child {_x000D_
<table id="t">_x000D_

Disable Drag and Drop on HTML elements?

using @SyntaxError's answer,

I've managed to do this in React; the only way I could figure out was to attach the ondragstart and ondrop methods to a ref, like so:

  const panelManagerBody = React.createRef<HTMLDivElement>();
  useEffect(() => {
    if (panelManagerBody.current) {
      panelManagerBody.current.ondragstart = () => false;
      panelManagerBody.current.ondrop = () => false;
  }, [panelManagerBody]);

  return (
    <div ref={panelManagerBody}>

What does <> mean?

could be a shorthand for React.Fragment

WPF TemplateBinding vs RelativeSource TemplatedParent

TemplateBinding is not quite the same thing. MSDN docs are often written by people that have to quiz monosyllabic SDEs about software features, so the nuances are not quite right.

TemplateBindings are evaluated at compile time against the type specified in the control template. This allows for much faster instantiation of compiled templates. Just fumble the name in a templatebinding and you'll see that the compiler will flag it.

The binding markup is resolved at runtime. While slower to execute, the binding will resolve property names that are not visible on the type declared by the template. By slower, I'll point out that its kind of relative since the binding operation takes very little of the application's cpu. If you were blasting control templates around at high speed you might notice it.

As a matter of practice use the TemplateBinding when you can but don't fear the Binding.

Java: How to convert String[] to List or Set

If you really want to use a set:

String[] strArray = {"foo", "foo", "bar"};  
Set<String> mySet = new HashSet<String>(Arrays.asList(strArray));


[foo, bar]

Change language for bootstrap DateTimePicker

you need to add the javascript language file,after the moment library, example:

<script type="text/javascript" src="js/moment/moment.js"></script>
<script type="text/javascript" src="js/moment/es.js"></script>

now you can set a language.

<script type="text/javascript">
$(function () {

Here are all language:

How to use the CSV MIME-type?

You could try to force the browser to open a "Save As..." dialog by doing something like:

header('Content-type: text/csv');
header('Content-disposition: attachment;filename=MyVerySpecial.csv');
echo "cell 1, cell 2";

Which should work across most major browsers.

VB.NET: how to prevent user input in a ComboBox

---- in form level Declaration of cbx veriable---

Dim cbx as string

Private Sub comboBox1_Enter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles comboBox1.Enter
    cbx = Me.comboBox1.Text
End Sub

Private Sub comboBox1_Leave(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles comboBox1.Leave
    Me.comboBox1.Text = cbx
End Sub

How to get first record in each group using Linq

Use it to achieve what you want. Then decide which properties you want to return.

yourList.OrderBy(l => l.Id).GroupBy(l => new { GroupName = l.F1}).Select(r => r.Key.GroupName)

Adding local .aar files to Gradle build using "flatDirs" is not working

The easiest way now is to add it as a module

enter image description here

This will create a new module containing the aar file, so you just need to include that module as a dependency afterwards

List all employee's names and their managers by manager name using an inner join

Select e.lastname as employee ,m.lastname as manager
  from employees e,employees m
 where e.managerid=m.employyid(+)

Force flushing of output to a file while bash script is still running

bash itself will never actually write any output to your log file. Instead, the commands it invokes as part of the script will each individually write output and flush whenever they feel like it. So your question is really how to force the commands within the bash script to flush, and that depends on what they are.

In LINQ, select all values of property X where X != null

I tend to create a static class containing basic functions for cases like these. They allow me write expressions like

var myValues myItems.Select(x => x.Value).Where(Predicates.IsNotNull);

And the collection of predicate functions:

public static class Predicates
    public static bool IsNull<T>(T value) where T : class
        return value == null;

    public static bool IsNotNull<T>(T value) where T : class
        return value != null;

    public static bool IsNull<T>(T? nullableValue) where T : struct
        return !nullableValue.HasValue;

    public static bool IsNotNull<T>(T? nullableValue) where T : struct
        return nullableValue.HasValue;

    public static bool HasValue<T>(T? nullableValue) where T : struct
        return nullableValue.HasValue;

    public static bool HasNoValue<T>(T? nullableValue) where T : struct
        return !nullableValue.HasValue;

Finding the number of days between two dates

$early_start_date = date2sql($_POST['early_leave_date']);

$date = new DateTime($early_start_date);
$date->modify('+1 day');

$date_a = new DateTime($early_start_date . ' ' . $_POST['start_hr'] . ':' . $_POST['start_mm']);
$date_b = new DateTime($date->format('Y-m-d') . ' ' . $_POST['end_hr'] . ':' . $_POST['end_mm']);

$interval = date_diff($date_a, $date_b);

$time = $interval->format('%h:%i');
$parsed = date_parse($time);
$seconds = $parsed['hour'] * 3600 + $parsed['minute'] * 60;
//        display_error($seconds);

$second3 = $employee_information['shift'] * 60 * 60;

if ($second3 < $seconds)
    display_error(_('Leave time can not be greater than shift time.Please try again........'));
    return FALSE;

.Contains() on a list of custom class objects

You need to implement IEquatable or override Equals() and GetHashCode()

For example:

public class CartProduct : IEquatable<CartProduct>
    public Int32 ID;
    public String Name;
    public Int32 Number;
    public Decimal CurrentPrice;

    public CartProduct(Int32 ID, String Name, Int32 Number, Decimal CurrentPrice)
        this.ID = ID;
        this.Name = Name;
        this.Number = Number;
        this.CurrentPrice = CurrentPrice;

    public String ToString()
        return Name;

    public bool Equals( CartProduct other )
        // Would still want to check for null etc. first.
        return this.ID == other.ID && 
               this.Name == other.Name && 
               this.Number == other.Number && 
               this.CurrentPrice == other.CurrentPrice;

call javascript function on hyperlink click

The simplest answer of all is...

<a href="javascript:alert('You clicked!')">My link</a>

Or to answer the question of calling a javascript function:

<script type="text/javascript">_x000D_
function myFunction(myMessage) {_x000D_
<a href="javascript:myFunction('You clicked!')">My link</a>

How to make circular background using css?

It can be done using the border-radius property. basically, you need to set the border-radius to exactly half of the height and width to get a circle.



<div id="container">
    <div id="inner">


    border:1px black solid;

    -moz-border-radius: 100px;
    -webkit-border-radius: 100px;
    border-radius: 100px;

SEVERE: ContainerBase.addChild: start:org.apache.catalina.LifecycleException: Failed to start error

My problem was that I had @WebServlet("/route") and the same servlet declared in web.xml

ASP.NET Display "Loading..." message while update panel is updating

You can use code as below when

using Image as Loading

<asp:UpdateProgress id="updateProgress" runat="server">
        <div style="position: fixed; text-align: center; height: 100%; width: 100%; top: 0; right: 0; left: 0; z-index: 9999999; background-color: #000000; opacity: 0.7;">
            <asp:Image ID="imgUpdateProgress" runat="server" ImageUrl="~/images/ajax-loader.gif" AlternateText="Loading ..." ToolTip="Loading ..." style="padding: 10px;position:fixed;top:45%;left:50%;" />

using Text as Loading

<asp:UpdateProgress id="updateProgress" runat="server">
        <div style="position: fixed; text-align: center; height: 100%; width: 100%; top: 0; right: 0; left: 0; z-index: 9999999; background-color: #000000; opacity: 0.7;">
            <span style="border-width: 0px; position: fixed; padding: 50px; background-color: #FFFFFF; font-size: 36px; left: 40%; top: 40%;">Loading ...</span>

Can someone explain how to append an element to an array in C programming?

For some people which might still see this question, there is another way on how to append another array element(s) in C. You can refer to this blog which shows a C code on how to append another element in your array.

But you can also use memcpy() function, to append element(s) of another array. You can use memcpy()like this:

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

int main(void)

int first_array[10] = {45, 2, 48, 3, 6};
int scnd_array[] = {8, 14, 69, 23, 5};

// 5 is the number of the elements which are going to be appended
memcpy(a + 5, b, 5 * sizeof(int));

// loop through and print all the array
for (i = 0; i < 10; i++) {
    printf("%d\n", a[i]);


A valid provisioning profile for this executable was not found for debug mode

One of the cause could be your "project => Build Settings => Signing => Development Team" is different from your "target => Build Settings => Signing => Development Team", just make them same

How to run single test method with phpunit?

If you're using an XML configuration file, you can add the following inside the phpunit tag:



Linker error: "linker input file unused because linking not done", undefined reference to a function in that file

I think you are confused about how the compiler puts things together. When you use -c flag, i.e. no linking is done, the input is C++ code, and the output is object code. The .o files thus don't mix with -c, and compiler warns you about that. Symbols from object file are not moved to other object files like that.

All object files should be on the final linker invocation, which is not the case here, so linker (called via g++ front-end) complains about missing symbols.

Here's a small example (calling g++ explicitly for clarity):

PROG ?= myprog
OBJS = worker.o main.o

all: $(PROG)

        g++ -Wall -pedantic -ggdb -O2 -c -o $@ $<

$(PROG): $(OBJS)
        g++ -Wall -pedantic -ggdb -O2 -o $@ $(OBJS)

There's also makedepend utility that comes with X11 - helps a lot with source code dependencies. You might also want to look at the -M gcc option for building make rules.

Stretch background image css?

Just paste this into your line of codes:

<meta http-equiv="X-UA-Compatible" content="IE=Edge" />

What is a raw type and why shouldn't we use it?

What are raw types in Java, and why do I often hear that they shouldn't be used in new code?

Raw-types are ancient history of the Java language. In the beginning there were Collections and they held Objects nothing more and nothing less. Every operation on Collections required casts from Object to the desired type.

List aList = new ArrayList();
String s = "Hello World!";
String c = (String)aList.get(0);

While this worked most of the time, errors did happen

List aNumberList = new ArrayList();
String one = "1";//Number one
Integer iOne = (Integer)aNumberList.get(0);//Insert ClassCastException here

The old typeless collections could not enforce type-safety so the programmer had to remember what he stored within a collection.
Generics where invented to get around this limitation, the developer would declare the stored type once and the compiler would do it instead.

List<String> aNumberList = new ArrayList<String>();
Integer iOne = aNumberList.get(0);//Compile time error
String sOne = aNumberList.get(0);//works fine

For Comparison:

// Old style collections now known as raw types
List aList = new ArrayList(); //Could contain anything
// New style collections with Generics
List<String> aList = new ArrayList<String>(); //Contains only Strings

More complex the Compareable interface:

//raw, not type save can compare with Other classes
class MyCompareAble implements CompareAble
   int id;
   public int compareTo(Object other)
   {return - ((MyCompareAble)other).id;}
class MyCompareAble implements CompareAble<MyCompareAble>
   int id;
   public int compareTo(MyCompareAble other)
   {return -;}

Note that it is impossible to implement the CompareAble interface with compareTo(MyCompareAble) with raw types. Why you should not use them:

  • Any Object stored in a Collection has to be cast before it can be used
  • Using generics enables compile time checks
  • Using raw types is the same as storing each value as Object

What the compiler does: Generics are backward compatible, they use the same java classes as the raw types do. The magic happens mostly at compile time.

List<String> someStrings = new ArrayList<String>();
String one = someStrings.get(0);

Will be compiled as:

List someStrings = new ArrayList();
String one = (String)someStrings.get(0);

This is the same code you would write if you used the raw types directly. Thought I'm not sure what happens with the CompareAble interface, I guess that it creates two compareTo functions, one taking a MyCompareAble and the other taking an Object and passing it to the first after casting it.

What are the alternatives to raw types: Use generics

How to run the Python program forever?

How about this one?

import signal

This will let your program sleep until it receives a signal from some other process (or itself, in another thread), letting it know it is time to do something.

What are the differences between git branch, fork, fetch, merge, rebase and clone?

Here is Oliver Steele's image of how it all fits together:

enter image description here

How do I use shell variables in an awk script?

I just changed @Jotne's answer for "for loop".

for i in `seq 11 20`; do host myserver-$i | awk -v i="$i" '{print "myserver-"i" " $4}'; done

Remove #N/A in vlookup result

if you are looking to change the colour of the cell in case of vlookup error then go for conditional formatting . To do this go the "CONDITIONAL FORMATTING" > "NEW RULE". In this choose the "Select the rule type" = "Format only cells that contains" . After this the window below changes , in which choose "Error" in the first drop-down .After this proceed accordingly.

Unable to Resolve Module in React Native App

I had this error and then I realized that my package.json file was mostly empty. Make sure you have all the dependencies you have first.

use yarn add DEPENDENCY_NAME to add dependencies.

git am error: "patch does not apply"

What is a patch?

A patch is little more (see below) than a series of instructions: "add this here", "remove that there", "change this third thing to a fourth". That's why git tells you:

The copy of the patch that failed is found in:

You can open that patch in your favorite viewer or editor, open the files-to-be-changed in your favorite editor, and "hand apply" the patch, using what you know (and git does not) to figure out how "add this here" is to be done when the files-to-be-changed now look little or nothing like what they did when they were changed earlier, with those changes delivered to you as a patch.

A little more

A three-way merge introduces that "little more" information than the plain "series of instructions": it tells you what the original version of the file was as well. If your repository has the original version, your git can compare what you did to a file, to what the patch says to do to the file.

As you saw above, if you request the three-way merge, git can't find the "original version" in the other repository, so it can't even attempt the three-way merge. As a result you get no conflict markers, and you must do the patch-application by hand.

Using --reject

When you have to apply the patch by hand, it's still possible that git can apply most of the patch for you automatically and leave only a few pieces to the entity with the ability to reason about the code (or whatever it is that needs patching). Adding --reject tells git to do that, and leave the "inapplicable" parts of the patch in rejection files. If you use this option, you must still hand-apply each failing patch, and figure out what to do with the rejected portions.

Once you have made the required changes, you can git add the modified files and use git am --continue to tell git to commit the changes and move on to the next patch.

What if there's nothing to do?

Since we don't have your code, I can't tell if this is the case, but sometimes, you wind up with one of the patches saying things that amount to, e.g., "fix the spelling of a word on line 42" when the spelling there was already fixed.

In this particular case, you, having looked at the patch and the current code, should say to yourself: "aha, this patch should just be skipped entirely!" That's when you use the other advice git already printed:

If you prefer to skip this patch, run "git am --skip" instead.

If you run git am --skip, git will skip over that patch, so that if there were five patches in the mailbox, it will end up adding just four commits, instead of five (or three instead of five if you skip twice, and so on).

How to install a python library manually

I'm going to assume compiling the QuickFix package does not produce a file, but rather only compiles the Python bindings and relies on make install to put them in the appropriate place.

In this case, a quick and dirty fix is to compile the QuickFix source, locate the Python extension modules (you indicated on your system these end with a .so extension), and add that directory to your PYTHONPATH environmental variable e.g., add

export PYTHONPATH=~/path/to/python/extensions:PYTHONPATH

or similar line in your shell configuration file.

A more robust solution would include making sure to compile with ./configure --prefix=$HOME/.local. Assuming QuickFix knows to put the Python files in the appropriate site-packages, when you do make install, it should install the files to ~/.local/lib/pythonX.Y/site-packages, which, for Python 2.6+, should already be on your Python path as the per-user site-packages directory.

If, on the other hand, it did provide a file, simply run

python install --user

for Python 2.6+.