Programs & Examples On #Catransform3d

CATransform3D is a Objective-C/C struct defined by the Core Animation framework. It represents a homogeneous three-dimensional transform. (i.e. 3D transformation matrix)

How can I test that a variable is more than eight characters in PowerShell?

Use the length property of the [String] type:

if ($dbUserName.length -gt 8) {
    Write-Output "Please enter more than 8 characters."
    $dbUserName = Read-Host "Re-enter database username"

Please note that you have to use -gt instead of > in your if condition. PowerShell uses the following comparison operators to compare values and test conditions:

  • -eq = equals
  • -ne = not equals
  • -lt = less than
  • -gt = greater than
  • -le = less than or equals
  • -ge = greater than or equals

Max or Default?

One interesting difference that seems worth noting is that while FirstOrDefault and Take(1) generate the same SQL (according to LINQPad, anyway), FirstOrDefault returns a value--the default--when there are no matching rows and Take(1) returns no results... at least in LINQPad.

Unfinished Stubbing Detected in Mockito

You're nesting mocking inside of mocking. You're calling getSomeList(), which does some mocking, before you've finished the mocking for MyMainModel. Mockito doesn't like it when you do this.


public myTest(){
    MyMainModel mainModel =  Mockito.mock(MyMainModel.class);
    Mockito.when(mainModel.getList()).thenReturn(getSomeList()); --> Line 355


public myTest(){
    MyMainModel mainModel =  Mockito.mock(MyMainModel.class);
    List<SomeModel> someModelList = getSomeList();

To understand why this causes a problem, you need to know a little about how Mockito works, and also be aware in what order expressions and statements are evaluated in Java.

Mockito can't read your source code, so in order to figure out what you are asking it to do, it relies a lot on static state. When you call a method on a mock object, Mockito records the details of the call in an internal list of invocations. The when method reads the last of these invocations off the list and records this invocation in the OngoingStubbing object it returns.

The line


causes the following interactions with Mockito:

  • Mock method mainModel.getList() is called,
  • Static method when is called,
  • Method thenReturn is called on the OngoingStubbing object returned by the when method.

The thenReturn method can then instruct the mock it received via the OngoingStubbing method to handle any suitable call to the getList method to return someModelList.

In fact, as Mockito can't see your code, you can also write your mocking as follows:


This style is somewhat less clear to read, especially since in this case the null has to be casted, but it generates the same sequence of interactions with Mockito and will achieve the same result as the line above.

However, the line


causes the following interactions with Mockito:

  1. Mock method mainModel.getList() is called,
  2. Static method when is called,
  3. A new mock of SomeModel is created (inside getSomeList()),
  4. Mock method model.getName() is called,

At this point Mockito gets confused. It thought you were mocking mainModel.getList(), but now you're telling it you want to mock the model.getName() method. To Mockito, it looks like you're doing the following:

// ...

This looks silly to Mockito as it can't be sure what you're doing with mainModel.getList().

Note that we did not get to the thenReturn method call, as the JVM needs to evaluate the parameters to this method before it can call the method. In this case, this means calling the getSomeList() method.

Generally it is a bad design decision to rely on static state, as Mockito does, because it can lead to cases where the Principle of Least Astonishment is violated. However, Mockito's design does make for clear and expressive mocking, even if it leads to astonishment sometimes.

Finally, recent versions of Mockito add an extra line to the error message above. This extra line indicates you may be in the same situation as this question:

3: you are stubbing the behaviour of another mock inside before 'thenReturn' instruction if completed

git discard all changes and pull from upstream

You can do it in a single command:

git fetch --all && git reset --hard origin/master

Or in a pair of commands:

git fetch --all
git reset --hard origin/master

Note than you will lose ALL your local changes

Convert a binary NodeJS Buffer to JavaScript ArrayBuffer

I have already update my node to Version 5.0.0 And I work work with this:

function toArrayBuffer(buffer){
    var array = [];
    var json = buffer.toJSON();
    var list =

    for(var key in list){

    function fixcode(key){
            return '0'+key.toUpperCase()
            return key.toUpperCase()

    return array

I use it to check my vhd disk image.

regex to remove all text before a character

The regular expression:


Then get the part between parenthesis. In perl:

my var = "3.04_somename.jpg";
$var =~ m/^[^_]*_(.*)$/;
my fileName = $1;

In Java:

String var = "3.04_somename.jpg";
String fileName = "";
Pattern pattern = Pattern.compile("^[^_]*_(.*)$");
Matcher matcher = pattern.matcher(var);
if (matcher.matches()) {
    fileName =;


Failed to load the JNI shared Library (JDK)

You have change proper version of the JAVA_HOME and PATH in environmental variables.

HTML&CSS + Twitter Bootstrap: full page layout or height 100% - Npx

I know it's late in the day but might help someone else!

body,html {
  height: 100%;

.contentarea {

  * replace 160px with the sum of height of all other divs 
  * inc padding, margins etc 
  min-height: calc(100% - 160px); 

SQL Server - transactions roll back on error?

You are correct in that the entire transaction will be rolled back. You should issue the command to roll it back.

You can wrap this in a TRY CATCH block as follows


        INSERT INTO myTable (myColumns ...) VALUES (myValues ...);
        INSERT INTO myTable (myColumns ...) VALUES (myValues ...);
        INSERT INTO myTable (myColumns ...) VALUES (myValues ...);

    COMMIT TRAN -- Transaction Success!
    IF @@TRANCOUNT > 0
        ROLLBACK TRAN --RollBack in case of Error

    -- you can Raise ERROR with RAISEERROR() Statement including the details of the exception

How to call JavaScript function instead of href in HTML

Your should also separate the javascript from the HTML.

<a href="#" id="function-click"><img title="next page" alt="next page" src="/themes/me/img/arrn.png"></a>


myLink = document.getElementById('function-click');
myLink.onclick = ShowOld(2367,146986,2);

Just make sure the last line in the ShowOld function is:

return false;

as this will stop the link from opening in the browser.

BULK INSERT with identity (auto-increment) column

You have to do bulk insert with format file:

   BULK INSERT Employee FROM 'path\tempFile.csv ' 
   WITH (FORMATFILE = 'path\tempFile.fmt');

where format file (tempFile.fmt) looks like this:

1 SQLCHAR 0 50 "\t"  2  Name   SQL_Latin1_General_CP1_CI_AS
2 SQLCHAR 0 50 "\r\n" 3  Address  SQL_Latin1_General_CP1_CI_AS

more details here -

What is more efficient? Using pow to square or just multiply it with itself?

If the exponent is constant and small, expand it out, minimizing the number of multiplications. (For example, x^4 is not optimally x*x*x*x, but y*y where y=x*x. And x^5 is y*y*x where y=x*x. And so on.) For constant integer exponents, just write out the optimized form already; with small exponents, this is a standard optimization that should be performed whether the code has been profiled or not. The optimized form will be quicker in so large a percentage of cases that it's basically always worth doing.

(If you use Visual C++, std::pow(float,int) performs the optimization I allude to, whereby the sequence of operations is related to the bit pattern of the exponent. I make no guarantee that the compiler will unroll the loop for you, though, so it's still worth doing it by hand.)

[edit] BTW pow has a (un)surprising tendency to crop up on the profiler results. If you don't absolutely need it (i.e., the exponent is large or not a constant), and you're at all concerned about performance, then best to write out the optimal code and wait for the profiler to tell you it's (surprisingly) wasting time before thinking further. (The alternative is to call pow and have the profiler tell you it's (unsurprisingly) wasting time -- you're cutting out this step by doing it intelligently.)

Multiline TextView in Android?

I like neither of the answers. Simply set the inputType and the TextView will adapt to its content


Tested on a Nexus One (2.3) and Nexus 4 (4.4)

Android Recyclerview GridLayoutManager column spacing

When using CardView for children problem with spaces between items can by solved by setting app:cardUseCompatPadding to true.

For bigger margins enlarge item elevation. CardElevation is optional (use default value).


How to get all privileges back to the root user in MySQL?

If you facing grant permission access denied problem, you can try mysql to fix the problem:

grant all privileges on . to root@'localhost' identified by 'Your password';

grant all privileges on . to root@'IP ADDRESS' identified by 'Your password?';

your can try this on any mysql user, its working.

Use below command to login mysql with iP address.

mysql -h -u root -p

What is the use of "assert"?

The assert statement exists in almost every programming language. It helps detect problems early in your program, where the cause is clear, rather than later when some other operation fails.

When you do...

assert condition

... you're telling the program to test that condition, and immediately trigger an error if the condition is false.

In Python, it's roughly equivalent to this:

if not condition:
    raise AssertionError()

Try it in the Python shell:

>>> assert True # nothing happens
>>> assert False
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>

Assertions can include an optional message, and you can disable them when running the interpreter.

To print a message if the assertion fails:

assert False, "Oh no! This assertion failed!"

Do not use parenthesis to call assert like a function. It is a statement. If you do assert(condition, message) you'll be running the assert with a (condition, message) tuple as first parameter.

As for disabling them, when running python in optimized mode, where __debug__ is False, assert statements will be ignored. Just pass the -O flag:

python -O

See here for the relevant documentation.

What is the default encoding of the JVM?

Note that you can change the default encoding of the JVM using the confusingly-named property file.encoding.

If your application is particularly sensitive to encodings (perhaps through usage of APIs implying default encodings), then you should explicitly set this on JVM startup to a consistent (known) value.

Access-Control-Allow-Origin error sending a jQuery Post to Google API's

I solved the Access-Control-Allow-Origin error modifying the dataType parameter to dataType:'jsonp' and adding a crossDomain:true


    url: ''+key,
    data: myData,
    type: 'GET',
    crossDomain: true,
    dataType: 'jsonp',
    success: function() { alert("Success"); },
    error: function() { alert('Failed!'); },
    beforeSend: setHeader

Manage toolbar's navigation and back button from fragment in android

You have to manage your back button pressed action on your main Activity because your main Activity is container for your fragment.

First, add your all fragment to transaction.addToBackStack(null) and now navigation back button call will be going on main activity. I hope following code will help you...

    public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    return super.onOptionsItemSelected(item);

you can also use

Fragment fragment =fragmentManager.findFragmentByTag(Constant.TAG); 
if(fragment!=null) {          
      FragmentTransaction transaction = fragmentManager.beginTransaction();

And to change the title according to fragment name from fragment you can use the following code:

activity.getSupportActionBar().setTitle("Keyword Report Detail");

Maven artifact and groupId naming

Weirdness is highly subjective, I just suggest to follow the official recommendation:

Guide to naming conventions on groupId, artifactId and version

  • groupId will identify your project uniquely across all projects, so we need to enforce a naming schema. It has to follow the package name rules, what means that has to be at least as a domain name you control, and you can create as many subgroups as you want. Look at More information about package names.

    eg. org.apache.maven, org.apache.commons

    A good way to determine the granularity of the groupId is to use the project structure. That is, if the current project is a multiple module project, it should append a new identifier to the parent's groupId.

    eg. org.apache.maven, org.apache.maven.plugins, org.apache.maven.reporting

  • artifactId is the name of the jar without version. If you created it then you can choose whatever name you want with lowercase letters and no strange symbols. If it's a third party jar you have to take the name of the jar as it's distributed.

    eg. maven, commons-math

  • version if you distribute it then you can choose any typical version with numbers and dots (1.0, 1.1, 1.0.1, ...). Don't use dates as they are usually associated with SNAPSHOT (nightly) builds. If it's a third party artifact, you have to use their version number whatever it is, and as strange as it can look.

    eg. 2.0, 2.0.1, 1.3.1

How to find encoding of a file via script on Linux?

Sounds like you're looking for enca. It can guess and even convert between encodings. Just look at the man page.

Or, failing that, use file -i (linux) or file -I (osx). That will output MIME-type information for the file, which will also include the character-set encoding. I found a man-page for it, too :)

Waiting for Target Device to Come Online

Seems like Android Studio (using version 3.5.1) gets into a weird state after a while. This worked for me.

File -> Invalidate Caches / Restart -> Invalidate and Restart

javascript clear field value input

do like

<input name="name" id="name" type="text" value="Name" 
   onblur="fillField(this,'Name');" onfocus="clearField(this,'Name');"/>

and js

function fillField(input,val) {
      if(input.value == "")

function clearField(input,val) {
      if(input.value == val)


here is a demo fiddle of the same

How do I commit case-sensitive only filename changes in Git?

Using SourceTree I was able to do this all from the UI

  1. Rename FILE.ext to whatever.ext
  2. Stage that file
  3. Now rename whatever.ext to file.ext
  4. Stage that file again

It's a bit tedious, but if you only need to do it to a few files it's pretty quick

PHP Fatal error: Cannot redeclare class

You must use require_once() function.

Entity framework self referencing loop detected

Self-referencing as example

public class Employee {
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
    public int ManagerId { get; set; }
    public virtual Employee Manager { get; set; }

    public virtual ICollection<Employee> Employees { get; set; }

    public Employee() {
        Employees = new HashSet<Employee>();
HasMany(e => e.Employees)
    .WithRequired(e => e.Manager)
    .HasForeignKey(e => e.ManagerId)

Detect changes in the DOM

I have recently written a plugin that does exactly that - jquery.initialize

You use it the same way as .each function

$(".some-element").initialize( function(){
    $(this).css("color", "blue"); 

The difference from .each is - it takes your selector, in this case .some-element and wait for new elements with this selector in the future, if such element will be added, it will be initialized too.

In our case initialize function just change element color to blue. So if we'll add new element (no matter if with ajax or even F12 inspector or anything) like:

$("<div/>").addClass('some-element').appendTo("body"); //new element will have blue color!

Plugin will init it instantly. Also plugin makes sure one element is initialized only once. So if you add element, then .detach() it from body and then add it again, it will not be initialized again.

//initialized only once

Plugin is based on MutationObserver - it will work on IE9 and 10 with dependencies as detailed on the readme page.

How to sort a list/tuple of lists/tuples by the element at a given index?

For sorting by multiple criteria, namely for instance by the second and third elements in a tuple, let

data = [(1,2,3),(1,2,1),(1,1,4)]

and so define a lambda that returns a tuple that describes priority, for instance

sorted(data, key=lambda tup: (tup[1],tup[2]) )
[(1, 1, 4), (1, 2, 1), (1, 2, 3)]

How to open .mov format video in HTML video Tag?

Content Type for MOV videos are video/quicktime in my case. Adding type="video/mp4" to MOV video file solved issue in my case.

<video width="400" controls Autoplay=autoplay>
  <source src="D:/" type="video/mp4">

Add line break to 'git commit -m' from the command line

From Git documentation:

-m <msg>
Use the given <msg> as the commit message. If multiple -m options are given, their values are concatenated as separate paragraphs.

So, if you are looking for grouping multiple commit messages this should do the work:

git commit -m "commit message1" -m "commit message2"

'module' object has no attribute 'DataFrame'

I have faced similar problem, 'int' object has no attribute 'DataFrame',

This was because i have mistakenly used pd as a variable in my code and assigned an integer to it, while using the same pd as my pandas dataframe object by declaring - import pandas as pd.

I realized this, and changed my variable to something else, and fixed the error.

What is the difference between bindParam and bindValue?

From the manual entry for PDOStatement::bindParam:

[With bindParam] Unlike PDOStatement::bindValue(), the variable is bound as a reference and will only be evaluated at the time that PDOStatement::execute() is called.

So, for example:

$sex = 'male';
$s = $dbh->prepare('SELECT name FROM students WHERE sex = :sex');
$s->bindParam(':sex', $sex); // use bindParam to bind the variable
$sex = 'female';
$s->execute(); // executed with WHERE sex = 'female'


$sex = 'male';
$s = $dbh->prepare('SELECT name FROM students WHERE sex = :sex');
$s->bindValue(':sex', $sex); // use bindValue to bind the variable's value
$sex = 'female';
$s->execute(); // executed with WHERE sex = 'male'

How to install CocoaPods?

These are the complete steps that I usually follow. I am posting this steps as short as possible and assuming that you know about Mac and Xcode projects. First of all, open the terminal and use the following commands, and press enter after each command.

Type in the following command if you don't already have CocoaPods installed:

sudo gem install cocoapods

Now please move to your Xcode Project directory by using this following command, and replace /Your Xcode Project Directory Path with the actual path to the directory:

cd /Your Xcode Project Directory Path

Below are instructions for how to use CocoaPods. Please wait for some time after each and every command entered to the terminal to execute successfully.

  1. Searching for pods in terminal:

pod search networking (replace networking with which you want to search)

  1. Creating the pod file:

pod init

  1. Opening the pod file:

open -a Xcode Podfile

  1. Adding the pods: (After adding your pods you must save the podfile first and then head back to the terminal again.)
target 'WebServiceUsingMantleAFNetworking' do
# platform :ios, '8.0' //Choose your version of iOS
pod 'AFNetworking', '~> 2.6.0’



platform :ios, '8.0'
pod 'AFNetworking'
pod 'Mantle'
pod 'LBBlurredImage'
pod 'TSMessages'
pod 'ReactiveCocoa'
  1. Installing the pods:

pod install

  1. Check for updates of pods on existing project:

pod outdated

  1. Update the existing pods:

pod update

  1. Uninstall the Cocoapods from system:

sudo gem uninstall cocoapods

There is a complete tutorial for removing pods from your Xcode project on stackoverflow. You can check on this following link for more info.

How to remove CocoaPods from a project?


Hope this helped.

How to solve could not create the virtual machine error of Java Virtual Machine Launcher?

On ubuntu (version 18), some application support java 8 and do not support java 11. If this is the case , you can switch to java 8 by following instruction on below topic :

Check if a String is in an ArrayList of Strings

    List list1 = new ArrayList();

    List list2 = new ArrayList();
    list2.add("five"); x -> !list1.contains(x) ).forEach(x -> System.out.println(x));

The output is:


Eclipse reports rendering library more recent than ADT plug-in

Please try once uninstalling from Help-->Installation details

and try again installing using

Check existence of directory and create if doesn't exist

I had an issue with R 2.15.3 whereby while trying to create a tree structure recursively on a shared network drive I would get a permission error.

To get around this oddity I manually create the structure;

mkdirs <- function(fp) {
    if(!file.exists(fp)) {


Repository Pattern Step by Step Explanation

As a summary, I would describe the wider impact of the repository pattern. It allows all of your code to use objects without having to know how the objects are persisted. All of the knowledge of persistence, including mapping from tables to objects, is safely contained in the repository.

Very often, you will find SQL queries scattered in the codebase and when you come to add a column to a table you have to search code files to try and find usages of a table. The impact of the change is far-reaching.

With the repository pattern, you would only need to change one object and one repository. The impact is very small.

Perhaps it would help to think about why you would use the repository pattern. Here are some reasons:

  • You have a single place to make changes to your data access

  • You have a single place responsible for a set of tables (usually)

  • It is easy to replace a repository with a fake implementation for testing - so you don't need to have a database available to your unit tests

There are other benefits too, for example, if you were using MySQL and wanted to switch to SQL Server - but I have never actually seen this in practice!

Parsing jQuery AJAX response

     type: "POST",
     url: '/admin/systemgoalssystemgoalupdate?format=html',
     data: formdata,
     success: function (data) {
     dataType: "json"

How to deselect a selected UITableView cell?

If you want to select any table cell with the first click and deselect with the second, you should use this code:

- (void)tableView:(UITableView *)tableView 
        didSelectRowAtIndexPath:(NSIndexPath *)indexPath {   

    if (self.selectedIndexPath && 
        [indexPath compare:self.selectedIndexPath] == NSOrderedSame) {

        [tableView deselectRowAtIndexPath:indexPath animated:YES];
         self.selectedIndexPath = nil;
    else {
        self.selectedIndexPath = indexPath;

Select top 10 records for each category

I do it this way:

SELECT a.* FROM articles AS a
  LEFT JOIN articles AS a2 
    ON a.section = a2.section AND a.article_date <= a2.article_date
GROUP BY a.article_id
HAVING COUNT(*) <= 10;

update: This example of GROUP BY works in MySQL and SQLite only, because those databases are more permissive than standard SQL regarding GROUP BY. Most SQL implementations require that all columns in the select-list that aren't part of an aggregate expression are also in the GROUP BY.

Can Mockito capture arguments of a method called multiple times?

First of all: you should always import mockito static, this way the code will be much more readable (and intuitive) - the code samples below require it to work:

import static org.mockito.Mockito.*;

In the verify() method you can pass the ArgumentCaptor to assure execution in the test and the ArgumentCaptor to evaluate the arguments:

ArgumentCaptor<MyExampleClass> argument = ArgumentCaptor.forClass(MyExampleClass.class);
verify(yourmock, atleast(2)).myMethod(argument.capture());

List<MyExampleClass> passedArguments = argument.getAllValues();

for (MyExampleClass data : passedArguments){
    //assertSometing ...

The list of all passed arguments during your test is accessible via the argument.getAllValues() method.

The single (last called) argument's value is accessible via the argument.getValue() for further manipulation / checking or whatever you wish to do.

PHP check if file is an image

The getimagesize() should be the most definite way of working out whether the file is an image:

    $image = true;
} else {
    $image = false;

because this is a sample getimagesize() output:

Array (
[0] => 800
[1] => 450
[2] => 2
[3] => width="800" height="450"
[bits] => 8
[channels] => 3
[mime] => image/jpeg)

Fatal error: Namespace declaration statement has to be the very first statement in the script in

Sometimes the space after <?php visible if you are using the same editor, in my case I was using TextWrapper. Due to the file type configuration in the TextWrapper (in your case some other editor), you might not see the space. Use a different editor in your machine and you'll see it. Then remove them -- works perfectly afterward.

HTTP 400 (bad request) for logical error, not malformed request syntax

As of this time, the latest draft of the HTTPbis specification, which is intended to replace and make RFC 2616 obsolete, states:

The 400 (Bad Request) status code indicates that the server cannot or will not process the request because the received syntax is invalid, nonsensical, or exceeds some limitation on what the server is willing to process.

This definition, while of course still subject to change, ratifies the widely used practice of responding to logical errors with a 400.

Get root password for Google Cloud Engine VM

I tried "ManiIOT"'s solution and it worked surprisingly. I've added another role (Compute Admin Role) for my google user account from IAM admin. Then stopped and restarted the VM. Afterwards 'sudo passwd' let me to generate a new password for the user.

So here are steps.

  1. Go to IAM & Admin
  2. Select IAM
  3. Find your user name service account (basically your google account) and click Edit-member
  4. Add another role --> select 'Compute Engine' - 'Compute Admin'
  5. Restart your Compute VM
  6. open SSH shell and run the command 'sudo passwd'
  7. enter a brand new password. Voilà!

How can you find out which process is listening on a TCP or UDP port on Windows?

Programmatically, you need stuff from iphlpapi.h, for example GetTcpTable2(). Structures like MIB_TCP6ROW2 contain the owner PID.

How to count digits, letters, spaces for a string in Python?

def match_string(words):
    nums = 0
    letter = 0
    other = 0
    for i in words :
        if i.isalpha():
        elif i.isdigit():
    return nums,letter,other

x = match_string("Hello World")
(0, 10, 2)

ArithmeticException: "Non-terminating decimal expansion; no exact representable decimal result"

Answer for BigDecimal throws ArithmeticException

public static void main(String[] args) {
        int age = 30;
        BigDecimal retireMentFund = new BigDecimal("10000.00");
        BigDecimal yearsInRetirement = new BigDecimal("20.00");
        String name = " Dennis";
        for ( int i = age; i <=65; i++){
            recalculate(retireMentFund,new BigDecimal("0.10"));
        BigDecimal monthlyPension =   retireMentFund.divide(
                yearsInRetirement.divide(new BigDecimal("12"), new MathContext(2, RoundingMode.CEILING)), new MathContext(2, RoundingMode.CEILING));      
        System.out.println(name+ " will have £" + monthlyPension +" per month for retirement");
public static void recalculate (BigDecimal fundAmount, BigDecimal rate){
        fundAmount.multiply(rate.add(new BigDecimal("1.00")));

Add MathContext object in your divide method call and adjust precision and rounding mode. This should fix your problem

Submitting the value of a disabled input field

you can also use the Readonly attribute: the input is not gonna be grayed but it won't be editable

<input type="text" name="lat" value="22.2222" readonly="readonly" />

Time complexity of accessing a Python dict

You are not correct. dict access is unlikely to be your problem here. It is almost certainly O(1), unless you have some very weird inputs or a very bad hashing function. Paste some sample code from your application for a better diagnosis.

c# regex matches example

So you're trying to grab numeric values that are preceded by the token "%download%#"?

Try this pattern:


That should work. I don't think # or % are special characters in .NET Regex, but you'll have to either escape the backslash like \\ or use a verbatim string for the whole pattern:

var regex = new Regex(@"(?<=%download%#)\d+");
return regex.Matches(strInput);

Tested here:

NOTE: The lookbehind assertion (?<=...) is important because you don't want to include %download%# in your results, only the numbers after it. However, your example appears to require it before each string you want to capture. The lookbehind group will make sure it's there in the input string, but won't include it in the returned results. More on lookaround assertions here.

Two decimal places using printf( )

Try using a format like %d.%02d

int iAmount = 10050;
printf("The number with fake decimal point is %d.%02d", iAmount/100, iAmount%100);

Another approach is to type cast it to double before printing it using %f like this:

printf("The number with fake decimal point is %0.2f", (double)(iAmount)/100);

My 2 cents :)

jQuery Date Picker - disable past dates

You must create a new date object and set it as minDate when you initialize the datepickers

<label for="from">From</label> <input type="text" id="from" name="from"/> <label for="to">to</label> <input type="text" id="to" name="to"/>

var dateToday = new Date();
var dates = $("#from, #to").datepicker({
    defaultDate: "+1w",
    changeMonth: true,
    numberOfMonths: 3,
    minDate: dateToday,
    onSelect: function(selectedDate) {
        var option = == "from" ? "minDate" : "maxDate",
            instance = $(this).data("datepicker"),
            date = $.datepicker.parseDate(instance.settings.dateFormat || $.datepicker._defaults.dateFormat, selectedDate, instance.settings);
        dates.not(this).datepicker("option", option, date);

Edit - from your comment now it works as expected

Is there a way to get the source code from an APK file?

Below ONLINE tool:

it do ALL by one click: decompiled .java files + resources + xml (in one .zip file) with very good decompiler (jadx return java code in places/functions where other compiles return comments inside function like "unable to decompile" or some android assembler/machine code)

ASP.NET MVC 404 Error Handling

I've investigated A LOT on how to properly manage 404s in MVC (specifically MVC3), and this, IMHO is the best solution I've come up with:

In global.asax:

public class MvcApplication : HttpApplication
    protected void Application_EndRequest()
        if (Context.Response.StatusCode == 404)

            var rd = new RouteData();
            rd.DataTokens["area"] = "AreaName"; // In case controller is in another area
            rd.Values["controller"] = "Errors";
            rd.Values["action"] = "NotFound";

            IController c = new ErrorsController();
            c.Execute(new RequestContext(new HttpContextWrapper(Context), rd));


public sealed class ErrorsController : Controller
    public ActionResult NotFound()
        ActionResult result;

        object model = Request.Url.PathAndQuery;

        if (!Request.IsAjaxRequest())
            result = View(model);
            result = PartialView("_NotFound", model);

        return result;


If you're using IoC (e.g. AutoFac), you should create your controller using:

var rc = new RequestContext(new HttpContextWrapper(Context), rd);
var c = ControllerBuilder.Current.GetControllerFactory().CreateController(rc, "Errors");

Instead of

IController c = new ErrorsController();
c.Execute(new RequestContext(new HttpContextWrapper(Context), rd));



There are 6 scenarios that I can think of where an ASP.NET MVC3 apps can generate 404s.

Generated by ASP.NET:

  • Scenario 1: URL does not match a route in the route table.

Generated by ASP.NET MVC:

  • Scenario 2: URL matches a route, but specifies a controller that doesn't exist.

  • Scenario 3: URL matches a route, but specifies an action that doesn't exist.

Manually generated:

  • Scenario 4: An action returns an HttpNotFoundResult by using the method HttpNotFound().

  • Scenario 5: An action throws an HttpException with the status code 404.

  • Scenario 6: An actions manually modifies the Response.StatusCode property to 404.


  • (A) Show a custom 404 error page to the user.

  • (B) Maintain the 404 status code on the client response (specially important for SEO).

  • (C) Send the response directly, without involving a 302 redirection.

Solution Attempt: Custom Errors

    <customErrors mode="On">
        <error statusCode="404" redirect="~/Errors/NotFound"/>

Problems with this solution:

  • Does not comply with objective (A) in scenarios (1), (4), (6).
  • Does not comply with objective (B) automatically. It must be programmed manually.
  • Does not comply with objective (C).

Solution Attempt: HTTP Errors

    <httpErrors errorMode="Custom">
        <remove statusCode="404"/>
        <error statusCode="404" path="App/Errors/NotFound" responseMode="ExecuteURL"/>

Problems with this solution:

  • Only works on IIS 7+.
  • Does not comply with objective (A) in scenarios (2), (3), (5).
  • Does not comply with objective (B) automatically. It must be programmed manually.

Solution Attempt: HTTP Errors with Replace

    <httpErrors errorMode="Custom" existingResponse="Replace">
        <remove statusCode="404"/>
        <error statusCode="404" path="App/Errors/NotFound" responseMode="ExecuteURL"/>

Problems with this solution:

  • Only works on IIS 7+.
  • Does not comply with objective (B) automatically. It must be programmed manually.
  • It obscures application level http exceptions. E.g. can't use customErrors section, System.Web.Mvc.HandleErrorAttribute, etc. It can't only show generic error pages.

Solution Attempt customErrors and HTTP Errors

    <customErrors mode="On">
        <error statusCode="404" redirect="~/Errors/NotFound"/>


    <httpErrors errorMode="Custom">
        <remove statusCode="404"/>
        <error statusCode="404" path="App/Errors/NotFound" responseMode="ExecuteURL"/>

Problems with this solution:

  • Only works on IIS 7+.
  • Does not comply with objective (B) automatically. It must be programmed manually.
  • Does not comply with objective (C) in scenarios (2), (3), (5).

People that have troubled with this before even tried to create their own libraries (see But the previous solution seems to cover all the scenarios without the complexity of using an external library.

How do I execute .js files locally in my browser?

If you're using Google Chrome you can use the Chrome Dev Editor:

Where's the IE7/8/9/10-emulator in IE11 dev tools?

I posted an answer to this already when someone else asked the same question (see How to bring back "Browser mode" in IE11?).

Read my answer there for a fuller explaination, but in short:

  • They removed it deliberately, because compat mode is not actually really very good for testing compatibility.

  • If you really want to test for compatibility with any given version of IE, you need to test in a real copy of that IE version. MS provide free VMs on for you to use for this purpose.

  • The only way to get compat mode in IE11 is to set the X-UA-Compatible header. When you have this and the site defaults to compat mode, you will be able to set the mode in dev tools, but only between edge or the specified compat mode; other modes will still not be available.

Showing Thumbnail for link in WhatsApp || og:image meta-tag doesn't work

If after all these tips, the thumbnail is still not showing, try this:

My problem was that the double quotes from the og attributes were being removed when built for production (npm run build). The Minify module was doing that.

So the solution was to cancel this removal, setting the removeAttributeQuotes attribute to false:

minify: {
    removeAttributeQuotes: false,

In my development environment, I set it on the "" file. Set it at your equivalent file.

Just rebuild and it's now working.

How do I copy an object in Java?

I use Google's JSON library to serialize it then create a new instance of the serialized object. It does deep copy with a few restrictions:

  • there can't be any recursive references

  • it won't copy arrays of disparate types

  • arrays and lists should be typed or it won't find the class to instantiate

  • you may need to encapsulate strings in a class you declare yourself

I also use this class to save user preferences, windows and whatnot to be reloaded at runtime. It is very easy to use and effective.


public class SerialUtils {


public static String serializeObject(Object o) {
    Gson gson = new Gson();
    String serializedObject = gson.toJson(o);
    return serializedObject;

public static Object unserializeObject(String s, Object o){
    Gson gson = new Gson();
    Object object = gson.fromJson(s, o.getClass());
    return object;
public static Object cloneObject(Object o){
    String s = serializeObject(o);
    Object object = unserializeObject(s,o);
    return object;

Android, How to create option Menu

you can create options menu like below:

Menu XML code:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android=""

        android:title="About US"/>

How you can get the menu from MENU XML(Convert menu XML to java):

    public boolean onCreateOptionsMenu(Menu menu) {
        return super.onCreateOptionsMenu(menu);

How to get Selected Item from Menu:

    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()){

                //About US

                //Do Logout
        return super.onOptionsItemSelected(item);

Javascript: output current datetime in YYYY/mm/dd hh:m:sec format

Not tested, but something like this:

var now = new Date();
var str = now.getUTCFullYear().toString() + "/" +
          (now.getUTCMonth() + 1).toString() +
          "/" + now.getUTCDate() + " " + now.getUTCHours() +
          ":" + now.getUTCMinutes() + ":" + now.getUTCSeconds();

Of course, you'll need to pad the hours, minutes, and seconds to two digits or you'll sometimes get weird looking times like "2011/12/2 19:2:8."

Conflict with dependency ''. Resolved versions for app (23.1.0) and test app (23.0.1) differ

In my case, I added below code in dependencies of app level build.gradle

androidTestCompile('', {
    exclude group: '', module: 'support-annotations'

After that, I clean the project and rebuild.My problem solved.

How to connect to LocalDb

Use (localdb)\MSSQLLocalDBwith Windows Auth

Find max and second max salary for a employee table MySQL

try this

select max(salary) as first, 
       (select salary from employee order by salary desc limit 1, 1) as second 
from employee limit 1

Make a nav bar stick

add to your .nav css block the

position: fixed

and it will work

How to include view/partial specific styling in AngularJS

'use strict'; angular.module('app') .run( [ '$rootScope', '$state', '$stateParams', function($rootScope, $state, $stateParams) { $rootScope.$state = $state; $rootScope.$stateParams = $stateParams; } ] ) .config( [ '$stateProvider', '$urlRouterProvider', function($stateProvider, $urlRouterProvider) {

                .state('app', {
                    abstract: true,
                    url: '/app',
                    templateUrl: 'views/layout.html'
                .state('app.dashboard', {
                    url: '/dashboard',
                    templateUrl: 'views/dashboard.html',
                    ncyBreadcrumb: {
                        label: 'Dashboard',
                        description: ''
                    resolve: {
                        deps: [
                            function($ocLazyLoad) {
                                return $ocLazyLoad.load({
                                    serie: true,
                                    files: [
                .state('ram', {
                    abstract: true,
                    url: '/ram',
                    templateUrl: 'views/layout-ram.html'
                .state('ram.dashboard', {
                    url: '/dashboard',
                    templateUrl: 'views/dashboard-ram.html',
                    ncyBreadcrumb: {
                        label: 'test'
                    resolve: {
                        deps: [
                            function($ocLazyLoad) {
                                return $ocLazyLoad.load({
                                    serie: true,
                                    files: [

Remove rows with all or some NAs (missing values) in data.frame

One approach that's both general and yields fairly-readable code is to use the filter() function and the across() helper functions from the {dplyr} package.


vars_to_check <- c("rnor", "cfam")

# Filter a specific list of columns to keep only non-missing entries

df %>% 
                ~ !

# Filter all the columns to exclude NA
df %>% 
                ~ !

# Filter only numeric columns
df %>%
                ~ !

Similarly, there are also the variant functions in the dplyr package (filter_all, filter_at, filter_if) which accomplish the same thing:


vars_to_check <- c("rnor", "cfam")

# Filter a specific list of columns to keep only non-missing entries
df %>% 
  filter_at(.vars = vars(one_of(vars_to_check)),
            ~ !

# Filter all the columns to exclude NA
df %>% 
  filter_all(~ !

# Filter only numeric columns
df %>%
            ~ !

UIWebView open links in Safari

App rejection Note:

Finally UIWbView is dead and Apple will not longer accept it.

Apple started sending email to all the App owner who are still using UIWebView:

Deprecated API Usage - Apple will stop accepting submissions of apps that use UIWebView APIs.

Apple takes User Privacy very seriously and it is obvious that they won’t allow insecure webview.

So do remove UIWebView from your app as soon as possible. don't use try to use UIWebView in new created app and I Prefer to using WKWebView if possible

ITMS-90809: Deprecated API Usage - Apple will stop accepting submissions of apps that use UIWebView APIs . See for more information.


import UIKit
import WebKit

class WebInfoController: UIViewController,WKNavigationDelegate {

    var webView : WKWebView = {
        var webview = WKWebView()
        return webview

    var _fileName : String!

    override func viewDidLoad() {
        let url = Bundle.main.url(forResource: _fileName, withExtension: "html")!
        webView.loadFileURL(url, allowingReadAccessTo: url)
        let request = URLRequest(url: url)

    func webView(webView: WKWebView, didFailProvisionalNavigation navigation: WKNavigation!, withError error: NSError) {
    func webView(webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation!) {
        print("Strat to load")
    func webView(webView: WKWebView, didFinishNavigation navigation: WKNavigation!) {
        print("finish to load")

Bootstrap - How to add a logo to navbar class?

I found a solution on another thread that works - use the pull-left class:

 <a href="#" class="pull-left"><img src="/path/to/image.png"></a> 

Thanks to Michael in this thread:

Bootstrap - How to add a logo to navbar class?

installing vmware tools: location of GCC binary?

to avoid the problem with CDROM: sudo nano /etc/apt/sources.list

find your cdrom and comment it with #

save the changes: "cntrl + o", than exit the file: "cntrl + x"

and try to install again

How to delete the top 1000 rows from a table using Sql Server 2008?



How to force DNS refresh for a website?

So if the issue is you just created a website and your clients or any given ISP DNS is cached and doesn't show new site yet. Yes all the other stuff applies ipconfig reset browser etc. BUT here's an Idea and something I do from time to time. You can set an alternate network ISP's DNS in the tcpip properties on the NIC properties. So if your ISP is say telstra and it hasn't propagated or updated you can specify an alternate service providers dns there. if that isp dns is updated before your native one hey presto you will see new site.But there is lots of other tricks you can do to determine propagation and get mail to work prior to the DNS updating. drop me a line if any one wants to chat.

How to disable a link using only CSS?

It's possible to do it in CSS

<a href="" target="_blank" class="disabled">Google</a>

See at:

Please note that the text-decoration: none; and color: black; is not needed but it makes the link look more like plain text.

Live video streaming using Java?

You can do this today in Java with the Red5 media server from Flash. If you want to also decode and encode video in Java, you can use the Xuggler project.

C++ catching all exceptions

Let me just mention this here: the Java

catch (Exception e)

may NOT catch all exceptions! I've actually had this sort of thing happen before, and it's insantiy-provoking; Exception derives from Throwable. So literally, to catch everything, you DON'T want to catch Exceptions; you want to catch Throwable.

I know it sounds nitpicky, but when you've spent several days trying to figure out where the "uncaught exception" came from in code that was surrounded by a try ... catch (Exception e)" block comes from, it sticks with you.

Difference between number and integer datatype in oracle dictionary views

This is what I got from oracle documentation, but it is for oracle 10g release 2:

When you define a NUMBER variable, you can specify its precision (p) and scale (s) so that it is sufficiently, but not unnecessarily, large. Precision is the number of significant digits. Scale can be positive or negative. Positive scale identifies the number of digits to the right of the decimal point; negative scale identifies the number of digits to the left of the decimal point that can be rounded up or down.

The NUMBER data type is supported by Oracle Database standard libraries and operates the same way as it does in SQL. It is used for dimensions and surrogates when a text or INTEGER data type is not appropriate. It is typically assigned to variables that are not used for calculations (like forecasts and aggregations), and it is used for variables that must match the rounding behavior of the database or require a high degree of precision. When deciding whether to assign the NUMBER data type to a variable, keep the following facts in mind in order to maximize performance:

  • Analytic workspace calculations on NUMBER variables is slower than other numerical data types because NUMBER values are calculated in software (for accuracy) rather than in hardware (for speed).
  • When data is fetched from an analytic workspace to a relational column that has the NUMBER data type, performance is best when the data already has the NUMBER data type in the analytic workspace because a conversion step is not required.

How to log Apache CXF Soap Request and Soap Response using Log4j?

When configuring, putting org.apache.cxf logging level to INFO is enough to see the plain SOAP messages:

DEBUG is too verbose.

How to disable Google asking permission to regularly check installed apps on my phone?

It is also available in general settings

Settings -> Security -> Verify Apps

Just un-check it.

( I am running 4.2.2 but most probably it should be available in 4.0 and higher. Cant say about previous versions ... )

Create normal zip file programmatically

You can try SharpZipLib for that. Is is open source, platform independent pure c# code.

Using numpy to build an array of all combinations of two arrays

Here's yet another way, using pure NumPy, no recursion, no list comprehension, and no explicit for loops. It's about 20% slower than the original answer, and it's based on np.meshgrid.

def cartesian(*arrays):
    mesh = np.meshgrid(*arrays)  # standard numpy meshgrid
    dim = len(mesh)  # number of dimensions
    elements = mesh[0].size  # number of elements, any index will do
    flat = np.concatenate(mesh).ravel()  # flatten the whole meshgrid
    reshape = np.reshape(flat, (dim, elements)).T  # reshape and transpose
    return reshape

For example,

x = np.arange(3)
a = cartesian(x, x, x, x, x)


[[0 0 0 0 0]
 [0 0 0 0 1]
 [0 0 0 0 2]
 [2 2 2 2 0]
 [2 2 2 2 1]
 [2 2 2 2 2]]

m2e error in MavenArchiver.getManifest()

I solved this error in pom.xml by adding the below code

spring-rest-demo org.apache.maven.plugins maven-war-plugin 2.6

Getting the size of an array in an object

Javascript arrays have a length property. Use it like this:


How to find the socket buffer size of linux

Whilst, as has been pointed out, it is possible to see the current default socket buffer sizes in /proc, it is also possible to check them using sysctl (Note: Whilst the name includes ipv4 these sizes also apply to ipv6 sockets - the ipv6 tcp_v6_init_sock() code just calls the ipv4 tcp_init_sock() function):

 sysctl net.ipv4.tcp_rmem
 sysctl net.ipv4.tcp_wmem

However, the default socket buffers are just set when the sock is initialised but the kernel then dynamically sizes them (unless set using setsockopt() with SO_SNDBUF). The actual size of the buffers for currently open sockets may be inspected using the ss command (part of the iproute package), which can also provide a bunch more info on sockets like congestion control parameter etc. E.g. To list the currently open TCP (t option) sockets and associated memory (m) information:

ss -tm

Here's some example output:

State       Recv-Q Send-Q        Local Address:Port        Peer Address:Port
ESTAB       0      0   

Here's a brief explanation of skmem (socket memory) - for more info you'll need to look at the kernel sources (e.g. sock.h):

rb:sk_rcvbuf          # current receive buffer size
tb:sk_sndbuf          # current transmit buffer size
w:sk_wmem_queued      # persistent transmit queue size

Reversing a linked list in Java, recursively

//Recursive solution
class SLL
   int data;
   SLL next;

SLL reverse(SLL head)
  //base case - 0 or 1 elements
  if(head == null || == null) return head;

  SLL temp = reverse(; = head; = null;
  return temp;

How to export datagridview to excel using

Code below creates Excel File and saves it in D: drive It uses Microsoft office 2007

FIRST ADD REFERRANCE (Microsoft office 12.0 object library ) to your project

Then Add code given bellow to the Export button click event-

Private Sub Export_Button_Click(ByVal sender As System.Object, ByVal e As 
System.EventArgs) Handles VIEW_Button.Click

    Dim xlApp As Microsoft.Office.Interop.Excel.Application
    Dim xlWorkBook As Microsoft.Office.Interop.Excel.Workbook
    Dim xlWorkSheet As Microsoft.Office.Interop.Excel.Worksheet
    Dim misValue As Object = System.Reflection.Missing.Value
    Dim i As Integer
    Dim j As Integer

    xlApp = New Microsoft.Office.Interop.Excel.ApplicationClass
    xlWorkBook = xlApp.Workbooks.Add(misValue)
    xlWorkSheet = xlWorkBook.Sheets("sheet1")

    For i = 0 To DataGridView1.RowCount - 2
        For j = 0 To DataGridView1.ColumnCount - 1
            For k As Integer = 1 To DataGridView1.Columns.Count
                xlWorkSheet.Cells(1, k) = DataGridView1.Columns(k - 1).HeaderText
                xlWorkSheet.Cells(i + 2, j + 1) = DataGridView1(j, i).Value.ToString()



    MsgBox("You can find the file D:\vbexcel.xlsx")
End Sub

Private Sub releaseObject(ByVal obj As Object)
        obj = Nothing
    Catch ex As Exception
        obj = Nothing
    End Try
End Sub

SQL DELETE with JOIN another table for WHERE condition

How about:

DELETE guide_category  
  WHERE id_guide_category IN ( 

        SELECT id_guide_category 
          FROM guide_category AS gc
     LEFT JOIN guide AS g 
            ON g.id_guide = gc.id_guide
         WHERE g.title IS NULL


How to parse a string into a nullable int

Using delegates, the following code is able to provide reusability if you find yourself needing the nullable parsing for more than one structure type. I've shown both the .Parse() and .TryParse() versions here.

This is an example usage:

NullableParser.TryParseInt(ViewState["Id"] as string);

And here is the code that gets you there...

public class NullableParser
    public delegate T ParseDelegate<T>(string input) where T : struct;
    public delegate bool TryParseDelegate<T>(string input, out T outtie) where T : struct;
    private static T? Parse<T>(string input, ParseDelegate<T> DelegateTheParse) where T : struct
      if (string.IsNullOrEmpty(input)) return null;
      return DelegateTheParse(input);
    private static T? TryParse<T>(string input, TryParseDelegate<T> DelegateTheTryParse) where T : struct
      T x;
      if (DelegateTheTryParse(input, out x)) return x;
      return null;
    public static int? ParseInt(string input)
      return Parse<int>(input, new ParseDelegate<int>(int.Parse));
    public static int? TryParseInt(string input)
      return TryParse<int>(input, new TryParseDelegate<int>(int.TryParse));
    public static bool? TryParseBool(string input)
      return TryParse<bool>(input, new TryParseDelegate<bool>(bool.TryParse));
    public static DateTime? TryParseDateTime(string input)
      return TryParse<DateTime>(input, new TryParseDelegate<DateTime>(DateTime.TryParse));

how can I enable scrollbars on the WPF Datagrid?

This worked for me. The key is to use * as Row height.

<Grid x:Name="grid">
            <RowDefinition Height="60"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="10"/>

        <TabControl  Grid.Row="1" x:Name="tabItem">
                <TabItem x:Name="ta" 
                        Header="List of all Clients">
                        <DataGrid Name="clientsgrid" AutoGenerateColumns="True" Margin="2" 

List all of the possible goals in Maven 2?

The goal you indicate in the command line is linked to the lifecycle of Maven. For example, the build lifecycle (you also have the clean and site lifecycles which are different) is composed of the following phases:

  • validate: validate the project is correct and all necessary information is available.
  • compile: compile the source code of the project.
  • test: test the compiled source code using a suitable unit testing framework. These tests should not require the code be packaged or deployed.
  • package: take the compiled code and package it in its distributable format, such as a JAR.
  • integration-test: process and deploy the package if necessary into an environment where integration tests can be run.
  • verify: run any checks to verify the package is valid and meets quality criteria
  • install: install the package into the local repository, for use as a dependency in other projects locally.
  • deploy: done in an integration or release environment, copies the final package to the remote repository for sharing with other developers and projects.

You can find the list of "core" plugins here, but there are plenty of others plugins, such as the codehaus ones, here.

Set object property using reflection

Yes, you can use Type.InvokeMember():

using System.Reflection;
MyObject obj = new MyObject();
    BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty,
    Type.DefaultBinder, obj, "Value");

This will throw an exception if obj doesn't have a property called Name, or it can't be set.

Another approach is to get the metadata for the property, and then set it. This will allow you to check for the existence of the property, and verify that it can be set:

using System.Reflection;
MyObject obj = new MyObject();
PropertyInfo prop = obj.GetType().GetProperty("Name", BindingFlags.Public | BindingFlags.Instance);
if(null != prop && prop.CanWrite)
    prop.SetValue(obj, "Value", null);

Oracle client and networking components were not found

Technology used: Windows 7, UFT 32 bit, Data Source ODBC pointing out to 32 bit C:\Windows\System32\odbcad32.exe, Oracle client with both versions installed 32 bit and 64 bit.

What worked for me:

1.Start -> search for Edit the system environment variables
2.System Variables -> Edit Path
3.Place the path for Oracle client 32 bit in front of the path for Oracle Client 64 bit.



Read file content from S3 bucket with boto3

Using the client instead of resource:

s3 = boto3.client('s3')
result = s3.list_objects(Bucket = bucket, Prefix='/something/')
for o in result.get('Contents'):
    data = s3.get_object(Bucket=bucket, Key=o.get('Key'))
    contents = data['Body'].read()

How to add a default include path for GCC in Linux?

Create an alias for gcc with your favorite includes.

alias mygcc='gcc -I /whatever/'

Node Multer unexpected field

We have to make sure the type= file with name attribute should be same as the parameter name passed in upload.single('attr')

var multer  = require('multer');
var upload = multer({ dest: 'upload/'});
var fs = require('fs');

/** Permissible loading a single file, 
    the value of the attribute "name" in the form of "recfile". **/
var type = upload.single('recfile');'/upload', type, function (req,res) {

  /** When using the "single"
      data come in "req.file" regardless of the attribute "name". **/
  var tmp_path = req.file.path;

  /** The original name of the uploaded file
      stored in the variable "originalname". **/
  var target_path = 'uploads/' + req.file.originalname;

  /** A better way to copy the uploaded file. **/
  var src = fs.createReadStream(tmp_path);
  var dest = fs.createWriteStream(target_path);
  src.on('end', function() { res.render('complete'); });
  src.on('error', function(err) { res.render('error'); });


iPhone viewWillAppear not firing

Views are added "directly" by calling [view addSubview:subview]. Views are added "indirectly" by methods such as tab bars or nav bars that swap subviews.

Any time you call [view addSubview:subviewController.view], you should then call [subviewController viewWillAppear:NO] (or YES as your case may be).

I had this problem when I implemented my own custom root-view management system for a subscreen in a game. Manually adding the call to viewWillAppear cured my problem.

Get the Application Context In Fragment In Android?

Pretty late response but you can do the following in Kotlin:

activity?.applicationContext?.let { SymptomsAdapters(it, param2, param3, ...) }

(?.) is for safe null operation to prevent from the null pointer exception.

You do not want to create a new context as that can lead to memory leaks when interchanging between fragments or when the device changes rotation.

And as someone mentioned above, in Java you can obtain context in a fragment by doing the following:


Where does SVN client store user authentication data?

Read SVNBook | Client Credentials.

With modern SVN you can just run svn auth to display the list of cached credentials. Don't forget to make sure that you run up-to-date SVN client version because svn auth was introduced in version 1.9. The last line will specify the path to credential store which by default is %APPDATA%\Subversion\auth on Windows and ~/.subversion/auth/ on Unix-like systems.

PS C:\Users\MyUser> svn auth
Credential kind: svn.simple
Authentication realm: <https://svn.example.local:443> VisualSVN Server
Password cache: wincrypt
Password: [not shown]
Username: user

Credentials cache in 'C:\Users\MyUser\AppData\Roaming\Subversion' contains 5 credentials

Uncaught TypeError: Cannot read property 'msie' of undefined

$.browser was removed from jQuery starting with version 1.9. It is now available as a plugin. It's generally recommended to avoid browser detection, which is why it was removed.

jQuery: Clearing Form Inputs

I figured out what it was! When I cleared the fields using the each() method, it also cleared the hidden field which the php needed to run:

if ($_POST['action'] == 'addRunner') 

I used the :not() on the selection to stop it from clearing the hidden field.

Qt jpg image display

Using QPainter and QImage to paint on a window-widget (QMainWindow) (just another method)

class MainWindow : public QMainWindow
        void paintEvent(QPaintEvent* event) override;

        QImage image = QImage("/path/to/image.jpg");

// for convenience resize window to image size

void MainWindow::paintEvent(QPaintEvent* event)
    QPainter painter(this);
    QRect rect = event->rect();
    painter.drawImage(rect, image, rect);

int main(int argc, char** argv)
    QApplication a(argc, argv);

    MainWindow mainWindow;;
    return a.exec();

How to call a function within class?

Since these are member functions, call it as a member function on the instance, self.

def isNear(self, p):

Binding IIS Express to an IP Address

Change bindingInformation=":8080:"

And remember to turn off the firewall for IISExpress

font awesome icon in select option

If you want the caret down symbol, remove the "appearence: none" it implies to remove webkit and moz- as well from select in css.

Giving graphs a subtitle in matplotlib

I don't think there is anything built-in, but you can do it by leaving more space above your axes and using figtext:

figtext(.5,.9,'Foo Bar', fontsize=18, ha='center')
figtext(.5,.85,'Lorem ipsum dolor sit amet, consectetur adipiscing elit',fontsize=10,ha='center')

ha is short for horizontalalignment.

How do I write a correct micro-benchmark in Java?

There are many possible pitfalls for writing micro-benchmarks in Java.

First: You have to calculate with all sorts of events that take time more or less random: Garbage collection, caching effects (of OS for files and of CPU for memory), IO etc.

Second: You cannot trust the accuracy of the measured times for very short intervals.

Third: The JVM optimizes your code while executing. So different runs in the same JVM-instance will become faster and faster.

My recommendations: Make your benchmark run some seconds, that is more reliable than a runtime over milliseconds. Warm up the JVM (means running the benchmark at least once without measuring, that the JVM can run optimizations). And run your benchmark multiple times (maybe 5 times) and take the median-value. Run every micro-benchmark in a new JVM-instance (call for every benchmark new Java) otherwise optimization effects of the JVM can influence later running tests. Don't execute things, that aren't executed in the warmup-phase (as this could trigger class-load and recompilation).

Delete files older than 3 months old in a directory using .NET

Something like that

            foreach (FileInfo file in new DirectoryInfo("SomeFolder").GetFiles().Where(p => p.CreationTime < DateTime.Now.AddDays(-90)).ToArray())

Get table name by constraint name

SELECT constraint_name, constraint_type, column_name
from user_constraints natural join user_cons_columns
where table_name = "my_table_name";

will give you what you need

JSLint is suddenly reporting: Use the function form of "use strict"

If you're writing modules for NodeJS, they are already encapsulated. Tell JSLint that you've got node by including at the top of your file:

/*jslint node: true */

Error in : figure margins too large, Scatter plot

If you get this message in RStudio, clicking the 'broomstick' figure "Clear All Plots" in Plots tab and try plot() again.

Moreover Execute the command

Using Git, show all commits that are in one branch, but not the other(s)

Just use git cherry to pick all commits in the branch newFeature42 for example:

git cherry -v master newFeature42

How do I catch a PHP fatal (`E_ERROR`) error?

Nice solution found in Zend Framework 2:

 * ErrorHandler that can be used to catch internal PHP errors
 * and convert to an ErrorException instance.
abstract class ErrorHandler
     * Active stack
     * @var array
    protected static $stack = array();

     * Check if this error handler is active
     * @return bool
    public static function started()
        return (bool) static::getNestedLevel();

     * Get the current nested level
     * @return int
    public static function getNestedLevel()
        return count(static::$stack);

     * Starting the error handler
     * @param int $errorLevel
    public static function start($errorLevel = \E_WARNING)
        if (!static::$stack) {
            set_error_handler(array(get_called_class(), 'addError'), $errorLevel);

        static::$stack[] = null;

     * Stopping the error handler
     * @param  bool $throw Throw the ErrorException if any
     * @return null|ErrorException
     * @throws ErrorException If an error has been catched and $throw is true
    public static function stop($throw = false)
        $errorException = null;

        if (static::$stack) {
            $errorException = array_pop(static::$stack);

            if (!static::$stack) {

            if ($errorException && $throw) {
                throw $errorException;

        return $errorException;

     * Stop all active handler
     * @return void
    public static function clean()
        if (static::$stack) {

        static::$stack = array();

     * Add an error to the stack
     * @param int    $errno
     * @param string $errstr
     * @param string $errfile
     * @param int    $errline
     * @return void
    public static function addError($errno, $errstr = '', $errfile = '', $errline = 0)
        $stack = & static::$stack[count(static::$stack) - 1];
        $stack = new ErrorException($errstr, 0, $errno, $errfile, $errline, $stack);

This class allows you to start the specific ErrorHandler sometimes if you need it. And then you can also stop the Handler.

Use this class e.g. like this:

$return = call_function_raises_E_WARNING();

if ($innerException = ErrorHandler::stop()) {
    throw new Exception('Special Exception Text', 0, $innerException);

// or
ErrorHandler::stop(true); // directly throws an Exception;

Link to the full class code:

A maybe better solution is that one from Monolog:

Link to the full class code:

It can also handle FATAL_ERRORS using the register_shutdown_function function. According to this class a FATAL_ERROR is one of the following array(E_ERROR, E_PARSE, E_CORE_ERROR, E_COMPILE_ERROR, E_USER_ERROR).

class ErrorHandler
    // [...]

    public function registerExceptionHandler($level = null, $callPrevious = true)
        $prev = set_exception_handler(array($this, 'handleException'));
        $this->uncaughtExceptionLevel = $level;
        if ($callPrevious && $prev) {
            $this->previousExceptionHandler = $prev;

    public function registerErrorHandler(array $levelMap = array(), $callPrevious = true, $errorTypes = -1)
        $prev = set_error_handler(array($this, 'handleError'), $errorTypes);
        $this->errorLevelMap = array_replace($this->defaultErrorLevelMap(), $levelMap);
        if ($callPrevious) {
            $this->previousErrorHandler = $prev ?: true;

    public function registerFatalHandler($level = null, $reservedMemorySize = 20)
        register_shutdown_function(array($this, 'handleFatalError'));

        $this->reservedMemory = str_repeat(' ', 1024 * $reservedMemorySize);
        $this->fatalLevel = $level;

    // [...]

MySQL LEFT JOIN Multiple Conditions

Just move the extra condition into the JOIN ON criteria, this way the existence of b is not required to return a result

    LEFT JOIN b ON a.group_id=b.group_id AND b.user_id!=$_SESSION{['user_id']} 
    WHERE a.keyword LIKE '%".$keyword."%' 
    GROUP BY group_id

Binding a generic list to a repeater - ASP.NET

You may want to create a subRepeater.

<asp:Repeater ID="SubRepeater" runat="server" DataSource='<%# Eval("Fields") %>'>
    <span><%# Eval("Name") %></span>

You can also cast your fields

<%# ((ArrayFields)Container.DataItem).Fields[0].Name %>

Finally you could do a little CSV Function and write out your fields with a function

<%# GetAsCsv(((ArrayFields)Container.DataItem).Fields) %>

public string GetAsCsv(IEnumerable<Fields> fields)
  var builder = new StringBuilder();
  foreach(var f in fields)
  builder.Remove(builder.Length - 1);
  return builder.ToString();

Generating a PDF file from React Components

you can user canvans with jsPDF

import jsPDF from 'jspdf';
import html2canvas from 'html2canvas';

 _exportPdf = () => {

     html2canvas(document.querySelector("#capture")).then(canvas => {
        document.body.appendChild(canvas);  // if you want see your screenshot in body.
        const imgData = canvas.toDataURL('image/png');
        const pdf = new jsPDF();
        pdf.addImage(imgData, 'PNG', 0, 0);"download.pdf"); 


and you div with id capture is:


<div id="capture">
  <p>Hello in my life</p>
  <span>How can hellp you</span>

Singleton: How should it be used

Singletons give you the ability to combine two bad traits in one class. That's wrong in pretty much every way.

A singleton gives you:

  1. Global access to an object, and
  2. A guarantee that no more than one object of this type can ever be created

Number one is straightforward. Globals are generally bad. We should never make objects globally accessible unless we really need it.

Number two may sound like it makes sense, but let's think about it. When was the last time you **accidentally* created a new object instead of referencing an existing one? Since this is tagged C++, let's use an example from that language. Do you often accidentally write

std::ostream os;
os << "hello world\n";

When you intended to write

std::cout << "hello world\n";

Of course not. We don't need protection against this error, because that kind of error just doesn't happen. If it does, the correct response is to go home and sleep for 12-20 hours and hope you feel better.

If only one object is needed, simply create one instance. If one object should be globally accessible, make it a global. But that doesn't mean it should be impossible to create other instances of it.

The "only one instance is possible" constraint doesn't really protect us against likely bugs. But it does make our code very hard to refactor and maintain. Because quite often we find out later that we did need more than one instance. We do have more than one database, we do have more than one configuration object, we do want several loggers. Our unit tests may want to be able to create and recreate these objects every test, to take a common example.

So a singleton should be used if and only if, we need both the traits it offers: If we need global access (which is rare, because globals are generally discouraged) and we need to prevent anyone from ever creating more than one instance of a class (which sounds to me like a design issue). The only reason I can see for this is if creating two instances would corrupt our application state - probably because the class contains a number of static members or similar silliness. In which case the obvious answer is to fix that class. It shouldn't depend on being the only instance.

If you need global access to an object, make it a global, like std::cout. But don't constrain the number of instances that can be created.

If you absolutely, positively need to constrain the number of instances of a class to just one, and there is no way that creating a second instance can ever be handled safely, then enforce that. But don't make it globally accessible as well.

If you do need both traits, then 1) make it a singleton, and 2) let me know what you need that for, because I'm having a hard time imagining such a case.

How can I increment a date by one day in Java?

SimpleDateFormat dateFormat = new SimpleDateFormat( "yyyy-MM-dd" );
Calendar cal = Calendar.getInstance();
cal.setTime( dateFormat.parse( inputString ) );
cal.add( Calendar.DATE, 1 );

How do I change selected value of select2 dropdown with JqGrid?

if you want to set a selected item when you know the text from drop down list and don't know the value, here is an example:

Say you figured out a timezone and want to set it, but values has time_zone_id in them.

        var timeZone = Intl.DateTimeFormat().resolvedOptions().timeZone;
        var $select2 = $('#time-zone');
        var selected = $select2.find("option:contains('"+timeZone+"')").val();

Deserializing a JSON into a JavaScript object

I think this should help:

Also documentations also prove that you can use require() for json files:

var jsonfile = require("./path/to/jsonfile.json");
node = jsonfile.adjacencies.nodeTo;
node2 = jsonfile.adjacencies.nodeFrom;
node3 =$color;
//other things.

File tree view in Notepad++

If you want treeview like explorer, you can go with LightExplorer

Light Explorer in Notepad++

Download dll from here and paste it inside plugins folder in notepad++ installed directory. Restart notepad++ and then in menubar goto Plugins ->Light Explorer -> Light Explorer

How do I get multiple subplots in matplotlib?

import matplotlib.pyplot as plt

fig, ax = plt.subplots(2, 2)

ax[0, 0].plot(range(10), 'r') #row=0, col=0
ax[1, 0].plot(range(10), 'b') #row=1, col=0
ax[0, 1].plot(range(10), 'g') #row=0, col=1
ax[1, 1].plot(range(10), 'k') #row=1, col=1

enter image description here

How to convert index of a pandas dataframe into a column?

For MultiIndex you can extract its subindex using

df['si_name'] = R.index.get_level_values('si_name') 

where si_name is the name of the subindex.

How to format DateTime columns in DataGridView?

I used these code Hope it could help

dataGridView2.Rows[n].Cells[3].Value = item[2].ToString();
dataGridView2.Rows[n].Cells[3].Value = Convert.ToDateTime(item[2].ToString()).ToString("d");

Equivalent of jQuery .hide() to set visibility: hidden

There isn't one built in but you could write your own quite easily:

(function($) {
    $.fn.invisible = function() {
        return this.each(function() {
            $(this).css("visibility", "hidden");
    $.fn.visible = function() {
        return this.each(function() {
            $(this).css("visibility", "visible");

You can then call this like so:


Here's a working example.

JQUERY ajax passing value from MVC View to Controller

$('#btnSaveComments').click(function () {
    var comments = $('#txtComments').val();
    var selectedId = $('#hdnSelectedId').val();

        url: '<%: Url.Action("SaveComments")%>',
        data: { 'id' : selectedId, 'comments' : comments },
        type: "post",
        cache: false,
        success: function (savingStatu`enter code here`s) {
        error: function (xhr, ajaxOptions, thrownError) {
            $('#lblCommentsNotification').text("Error encountered while saving the comments.");

FileNotFoundError: [Errno 2] No such file or directory

For people who are still getting error despite of passing absolute path, should check that if file has a valid name. For me I was trying to create a file with '/' in the file name. As soon as I removed '/', I was able to create the file.

Understanding MongoDB BSON Document size limit

Nested Depth for BSON Documents: MongoDB supports no more than 100 levels of nesting for BSON documents.

More more info vist

C# winforms combobox dynamic autocomplete

In previous replies are drawbacks. Offers its own version with the selection in the drop down list the desired item:

    private ConnectSqlForm()
        cmbDatabases.TextChanged += UpdateAutoCompleteComboBox;
        cmbDatabases.KeyDown += AutoCompleteComboBoxKeyPress;

    private void UpdateAutoCompleteComboBox(object sender, EventArgs e)
        var comboBox = sender as ComboBox;
        if(comboBox == null)
        string txt = comboBox.Text;
        string foundItem = String.Empty;
        foreach(string item in comboBox.Items)
            if (!String.IsNullOrEmpty(txt) && item.ToLower().StartsWith(txt.ToLower()))
                foundItem = item;

        if (!String.IsNullOrEmpty(foundItem))
            if (String.IsNullOrEmpty(txt) || !txt.Equals(foundItem))
                comboBox.TextChanged -= UpdateAutoCompleteComboBox;
                comboBox.Text = foundItem;
                comboBox.DroppedDown = true;
                Cursor.Current = Cursors.Default;
                comboBox.TextChanged += UpdateAutoCompleteComboBox;

            comboBox.SelectionStart = txt.Length;
            comboBox.SelectionLength = foundItem.Length - txt.Length;
            comboBox.DroppedDown = false;

    private void AutoCompleteComboBoxKeyPress(object sender, KeyEventArgs e)
        var comboBox = sender as ComboBox;
        if (comboBox != null && comboBox.DroppedDown)
            switch (e.KeyCode)
                case Keys.Back:
                    int sStart = comboBox.SelectionStart;
                    if (sStart > 0)
                        comboBox.Text = sStart == 0 ? "" : comboBox.Text.Substring(0, sStart);
                    e.SuppressKeyPress = true;


Switching the order of block elements with CSS

I known this is old, but I found a easier solution and it works on ie10, firefox and chrome:

<div id="wrapper">
  <div id="one">One</div>
  <div id="two">Two</div>
  <div id="three">Three</div>

This is the css:

#wrapper {display:table;}
#one {display:table-footer-group;}
#three {display:table-header-group;}

And the result:


I found it here.

How to round an image with Glide library?

its very simple i have seen Glide library its very good library and essay base on volley Google's library

usethis library for rounded image view


//For a simple view:

 public void onCreate(Bundle savedInstanceState) {

  CircleImageView civProfilePic = (CircleImageView)findViewById(;

//For a list:

public View getView(int position, View recycled, ViewGroup container) {
final ImageView myImageView;
 if (recycled == null) {
    myImageView = (CircleImageView) inflater.inflate(R.layout.my_image_view,
            container, false);
} else {
    myImageView = (CircleImageView) recycled;

String url = myUrls.get(position);


  return myImageView;

and in XML

   app:border_color="@color/dark" />

Android layout replacing a view with another view on run time

private void replaceView(View oldV,View newV){
        ViewGroup par = (ViewGroup)oldV.getParent();
        if(par == null){return;}
        int i1 = par.indexOfChild(oldV);

Match exact string

"^" For the begining of the line "$" for the end of it. Eg.:

var re = /^abc$/;

Would match "abc" but not "1abc" or "abc1". You can learn more at

How to display alt text for an image in chrome

Various browsers (mis)handle this in various ways. Using title (an old IE 'standard') isn't particularly appropriate, since the title attribute is a mouseover effect. The jQuery solution above (Alexis) seems on the right track, but I don't think the 'error' occurs at a point where it could be caught. I've had success by replacing at the src with itself, and then catching the error:


This, as in the Alexis contribution, has the benefit of removing the missing img image.

How can I get the index from a JSON object with value?

You can use Array.findIndex.

var data= [{
  "name": "placeHolder",
  "section": "right"
}, {
  "name": "Overview",
  "section": "left"
}, {
  "name": "ByFunction",
  "section": "left"
}, {
  "name": "Time",
  "section": "left"
}, {
  "name": "allFit",
  "section": "left"
}, {
  "name": "allbMatches",
  "section": "left"
}, {
  "name": "allOffers",
  "section": "left"
}, {
  "name": "allInterests",
  "section": "left"
}, {
  "name": "allResponses",
  "section": "left"
}, {
  "name": "divChanged",
  "section": "right"
var index = data.findIndex(obj =>"allInterests");


How to change MenuItem icon in ActionBar programmatically

to use in onMenuItemClick(MenuItem item) just do invalidateOptionsMenu(); item.setIcon(ContextCompat.getDrawable(this, R.drawable.ic_baseline_play_circle_outline_24px));

test if display = none


How to get ID of clicked element with jQuery

First off you can't have just a number for your id unless you are using the HTML5 DOCTYPE. Secondly, you need to either remove the # in each id or replace it with this:


Cut Java String at a number of character

Jakarta Commons StringUtils.abbreviate(). If, for some reason you don't want to use a 3rd-party library, at least copy the source code.

One big benefit of this over the other answers to date is that it won't throw if you pass in a null.

Merging two CSV files using Python

You need to store all of the extra rows in the files in your dictionary, not just one of them:

dict1 = {row[0]: row[1:] for row in r}
dict2 = {row[0]: row[1:] for row in r}

Then, since the values in the dictionaries are lists, you need to just concatenate the lists together:

w.writerows([[key] + dict1.get(key, []) + dict2.get(key, []) for key in keys])

Uncaught TypeError: Object #<Object> has no method 'movingBoxes'

When I had this problem it was because I was trying to use an actual function in place of an anonymous function.


$(document).on('change', "#MyId", MyFunction());


$(document).on('change', "#MyId", MyFunction);

or also correct and if you need to pass event object or other params.

$(document).on('change', "#MyId", function(e) { MyFunction(e); });

Apple Mach-O Linker Error when compiling for device

Here is permanent solution.Generally overwriting project may cause this prolems.Try this method.

-UPDATE - Clang error - Mach-O Linker error

In some case error log window displaying .xctest error, to fix it

-> Select your project

-> Beside this(just before General tab) select your projectTest file from dropdown

-> There is one option (like ProjNameTests)

-> In Host Application, select your project from dropdown only if it show custom


enter image description here

Old method deleted

Detect browser or tab closing

onunload is the answer. Crossbrowser too.

window.onunload = function(){
    alert("The window is closing now!");

onunload executes only on page close:

These events fire when the window is unloading its content and resources.

I tested it on chrome, it doesn't execute even on page refresh and on navigating to a different page.

The alert may not display because of how javascript executes code.. but it will definitely hit the code.

Emulator in Android Studio doesn't start

It seems that "Waiting for target device to come online ..." is a generic message that appears, always, when the emulator can not start properly. And what's the cause of that? As you can see, there could be many causes.

I think the best way to find the concrete error with the emulator is to start it within a terminal. So:

1 - Open a terminal and go to this folder:~/Android/Sdk/tools

2 - Start the emulator with this command:

./emulator -avd EMULATOR_NAME -netspeed full -netdelay none

You can see the name of your (previously created with AVD Manager) emulators with this command:

./emulator -list-avds

If everything is ok, the program doesn't start, and it writes in the terminal the concrete error.

In my case, the application says that there is a problem loading the graphic driver ("libGL error: unable to load driver:"). As it is explained here, it seems that Google packaged with Android Studio an old version of one library, and the emulator fails when it tries to use my graphic card.

Solution? Very easy: to use the system libraries instead of the packaged in Android Studio. How? Adding "-use-system-libs" at the end of the command. So:

./emulator -avd EMULATOR_NAME -netspeed full -netdelay none -use-system-libs

The definitive solution is to set the ANDROID_EMULATOR_USE_SYSTEM_LIBS environment variable to 1 for your user/system. With this change, when I run the emulator within Android Studio, it will also load the system libraries.

PS 1 - The easiest way I found to set the environment variable, it's to modify the script that launch the Android Studio (, in my case it is inside /opt/android-stuido/bin), and add at the begining this:


PS 2 - I work with Debian Jessie and Android Studio 2.2.3. My graphic card is an ATI Radeon HD 6850 by Sapphire.

UPDATE December 2017: I had the same problem with Debian Stretch and Android Studio 3.0.1 (same graphic card). The same solution works for me.

Remove warning messages in PHP

I do it as follows in my php.ini:

error_reporting = E_ALL & ~E_WARNING  & ~E_NOTICE & ~E_STRICT & ~E_DEPRECATED

This logs only fatal errors and no warnings.

How to declare and initialize a static const array as a class member?

// in foo.h
class Foo {
    static const unsigned char* Msg;

// in foo.cpp
static const unsigned char Foo_Msg_data[] = {0x00,0x01};
const unsigned char* Foo::Msg = Foo_Msg_data;

fatal error: mpi.h: No such file or directory #include <mpi.h>

As suggested above the inclusion of


in the include path takes care of this (in my case)

SQL Server query to find all permissions/access for all users in a database

CREATE PROCEDURE Get_permission 
    DECLARE @db_name  VARCHAR(200), 
            @sql_text VARCHAR(max) 

    SET @sql_text='Create table ##db_name (user_name varchar(max),' 

    DECLARE db_cursor CURSOR FOR 
      SELECT name 
      FROM   sys.databases 

    OPEN db_cursor 

    FETCH next FROM db_cursor INTO @db_name 

          SET @sql_text=@sql_text + @db_name + ' varchar(max),' 

          FETCH next FROM db_cursor INTO @db_name 

    CLOSE db_cursor 

    SET @sql_text=@sql_text + 'Server_perm varchar(max))' 

    EXEC (@sql_text) 

    DEALLOCATE db_cursor 

    DECLARE @RoleName VARCHAR(50) 
    DECLARE @UserName VARCHAR(50) 

    CREATE TABLE #permission 
         user_name    VARCHAR(50), 
         databasename VARCHAR(50), 
         role         VARCHAR(50) 

    DECLARE longspcur CURSOR FOR 
      SELECT name 
      FROM   sys.server_principals 
      WHERE  type IN ( 'S', 'U', 'G' ) 
             AND principal_id > 4 
             AND name NOT LIKE '##%' 
             AND name <> 'NT AUTHORITY\SYSTEM' 
             AND name <> 'ONDEMAND\Administrator' 
             AND name NOT LIKE 'steel%' 

    OPEN longspcur 

    FETCH next FROM longspcur INTO @UserName 

          CREATE TABLE #userroles_kk 
               databasename VARCHAR(50), 
               role         VARCHAR(50) 

          CREATE TABLE #rolemember_kk 
               dbrole     VARCHAR(100), 
               membername VARCHAR(100), 
               membersid  VARBINARY(2048) 

          SET @CMD = 'use ? truncate table #RoleMember_kk insert into #RoleMember_kk exec sp_helprolemember  insert into #UserRoles_kk (DatabaseName, Role) select db_name(), dbRole from #RoleMember_kk where MemberName = ''' + @UserName + '''' 

          EXEC Sp_msforeachdb 

          INSERT INTO #permission 
          SELECT @UserName 'user', 
          FROM   sys.sysdatabases b 
                 LEFT OUTER JOIN #userroles_kk u 
                              ON u.databasename = --and u.Role='db_owner' 
          ORDER  BY 1 

          DROP TABLE #userroles_kk; 

          DROP TABLE #rolemember_kk; 

          FETCH next FROM longspcur INTO @UserName 

    CLOSE longspcur 

    DEALLOCATE longspcur 

    TRUNCATE TABLE ##db_name 

    DECLARE @d1 VARCHAR(max), 
            @d2 VARCHAR(max), 
            @d3 VARCHAR(max), 
            @ss VARCHAR(max) 
    DECLARE perm_cur CURSOR FOR 
      SELECT * 
      FROM   #permission 
      ORDER  BY 2 DESC 

    OPEN perm_cur 

    FETCH next FROM perm_cur INTO @d1, @d2, @d3 

                        FROM   ##db_name 
                        WHERE  user_name = @d1) 
                SET @ss='insert into ##db_name(user_name) values (''' 
                        + @d1 + ''')' 

                EXEC (@ss) 

                SET @ss='update ##db_name set ' + @d2 + '=''' + @d3 
                        + ''' where user_name=''' + @d1 + '''' 

                EXEC (@ss) 
                DECLARE @var            NVARCHAR(max), 
                        @ParmDefinition NVARCHAR(max), 
                        @var1           NVARCHAR(max) 

                SET @var = N'select @var1=' + @d2 
                           + ' from ##db_name where USER_NAME=''' + @d1 
                           + ''''; 
                SET @ParmDefinition = N'@var1 nvarchar(300) OUTPUT'; 

                EXECUTE Sp_executesql 
                  @var1=@var1 output; 

                SET @var1=Isnull(@var1, ' ') 
                SET @var= '  update ##db_name set ' + @d2 + '=''' + @var1 + ' ' 
                          + @d3 + ''' where user_name=''' + @d1 + '''  ' 

                EXEC (@var) 

          FETCH next FROM perm_cur INTO @d1, @d2, @d3 

    CLOSE perm_cur 

    DEALLOCATE perm_cur 

    SELECT * 
    FROM   ##db_name 

    DROP TABLE ##db_name 

    DROP TABLE #permission 

How to print a string multiple times?

The question is a bit unclear can't you just repeat the for loop?


for i in a:
    print i

for i in a:
    print i

What is the purpose of using WHERE 1=1 in SQL statements?

People use it because they're inherently lazy when building dynamic SQL queries. If you start with a "where 1 = 1" then all your extra clauses just start with "and" and you don't have to figure out.

Not that there's anything wrong with being inherently lazy. I've seen doubly-linked lists where an "empty" list consists of two sentinel nodes and you start processing at the first->next up until last->prev inclusive.

This actually removed all the special handling code for deleting first and last nodes. In this set-up, every node was a middle node since you weren't able to delete first or last. Two nodes were wasted but the code was simpler and (ever so slightly) faster.

The only other place I've ever seen the "1 = 1" construct is in BIRT. Reports often use positional parameters and are modified with Javascript to allow all values. So the query:

select * from tbl where col = ?

when the user selects "*" for the parameter being used for col is modified to read:

select * from tbl where ((col = ?) or (1 = 1))

This allows the new query to be used without fiddling around with the positional parameter details. There's still exactly one such parameter. Any decent DBMS (e.g., DB2/z) will optimize that query to basically remove the clause entirely before trying to construct an execution plan, so there's no trade-off.

How To Define a JPA Repository Query with a Join

You are experiencing this issue for two reasons.

  • The JPQL Query is not valid.
  • You have not created an association between your entities that the underlying JPQL query can utilize.

When performing a join in JPQL you must ensure that an underlying association between the entities attempting to be joined exists. In your example, you are missing an association between the User and Area entities. In order to create this association we must add an Area field within the User class and establish the appropriate JPA Mapping. I have attached the source for User below. (Please note I moved the mappings to the fields)

public class User {

    private Long idUser;

    private String userName;

    private Area area;

    public Long getIdUser() {
        return idUser;

    public void setIdUser(Long idUser) {
        this.idUser = idUser;

    public String getUserName() {
        return userName;

    public void setUserName(String userName) {
        this.userName = userName;

    public Area getArea() {
        return area;

    public void setArea(Area area) {
        this.area = area;

Once this relationship is established you can reference the area object in your @Query declaration. The query specified in your @Query annotation must follow proper syntax, which means you should omit the on clause. See the following:

@Query("select u.userName from User u inner join u.area ar where ar.idArea = :idArea")

While looking over your question I also made the relationship between the User and Area entities bidirectional. Here is the source for the Area entity to establish the bidirectional relationship.

@Table(name = "area")
public class Area {

    private Long idArea;

    private String areaName;

    @OneToOne(fetch=FetchType.LAZY, mappedBy="area")
    private User user;

    public Long getIdArea() {
        return idArea;

    public void setIdArea(Long idArea) {
        this.idArea = idArea;

    public String getAreaName() {
        return areaName;

    public void setAreaName(String areaName) {
        this.areaName = areaName;

    public User getUser() {
        return user;

    public void setUser(User user) {
        this.user = user;

static and extern global variables in C and C++

Global variables are not extern nor static by default on C and C++. When you declare a variable as static, you are restricting it to the current source file. If you declare it as extern, you are saying that the variable exists, but are defined somewhere else, and if you don't have it defined elsewhere (without the extern keyword) you will get a link error (symbol not found).

Your code will break when you have more source files including that header, on link time you will have multiple references to varGlobal. If you declare it as static, then it will work with multiple sources (I mean, it will compile and link), but each source will have its own varGlobal.

What you can do in C++, that you can't in C, is to declare the variable as const on the header, like this:

const int varGlobal = 7;

And include in multiple sources, without breaking things at link time. The idea is to replace the old C style #define for constants.

If you need a global variable visible on multiple sources and not const, declare it as extern on the header, and then define it, this time without the extern keyword, on a source file:

Header included by multiple files:

extern int varGlobal;

In one of your source files:

int varGlobal = 7;

How can I specify the schema to run an sql file against in the Postgresql command line

I'm using something like this and works very well:* :-)

(echo "set schema 'acme';" ; \
  cat ~/git/soluvas-framework/schedule/src/main/resources/org/soluvas/schedule/tables_postgres.sql) \
  | psql -Upostgres -hlocalhost quikdo_app_dev 

Note: Linux/Mac/Bash only, though probably there's a way to do that in Windows/PowerShell too.

Assembly - JG/JNLE/JL/JNGE after CMP

When you do a cmp a,b, the flags are set as if you had calculated a - b.

Then the jmp-type instructions check those flags to see if the jump should be made.

In other words, the first block of code you have (with my comments added):

cmp al,dl     ; set flags based on the comparison
jg label1     ; then jump based on the flags

would jump to label1 if and only if al was greater than dl.

You're probably better off thinking of it as al > dl but the two choices you have there are mathematically equivalent:

al > dl
al - dl > dl - dl (subtract dl from both sides)
al - dl > 0       (cancel the terms on the right hand side)

You need to be careful when using jg inasmuch as it assumes your values were signed. So, if you compare the bytes 101 (101 in two's complement) with 200 (-56 in two's complement), the former will actually be greater. If that's not what was desired, you should use the equivalent unsigned comparison.

See here for more detail on jump selection, reproduced below for completeness. First the ones where signed-ness is not appropriate:

|Instr   | Description                  | signed-ness | Flags              |
| JO     | Jump if overflow             |             | OF = 1             |
| JNO    | Jump if not overflow         |             | OF = 0             |
| JS     | Jump if sign                 |             | SF = 1             |
| JNS    | Jump if not sign             |             | SF = 0             |
| JE/    | Jump if equal                |             | ZF = 1             |
| JZ     | Jump if zero                 |             |                    |
| JNE/   | Jump if not equal            |             | ZF = 0             |
| JNZ    | Jump if not zero             |             |                    |
| JP/    | Jump if parity               |             | PF = 1             |
| JPE    | Jump if parity even          |             |                    |
| JNP/   | Jump if no parity            |             | PF = 0             |
| JPO    | Jump if parity odd           |             |                    |
| JCXZ/  | Jump if CX is zero           |             | CX = 0             |
| JECXZ  | Jump if ECX is zero          |             | ECX = 0            |

Then the unsigned ones:

|Instr   | Description                  | signed-ness | Flags              |
| JB/    | Jump if below                | unsigned    | CF = 1             |
| JNAE/  | Jump if not above or equal   |             |                    |
| JC     | Jump if carry                |             |                    |
| JNB/   | Jump if not below            | unsigned    | CF = 0             |
| JAE/   | Jump if above or equal       |             |                    |
| JNC    | Jump if not carry            |             |                    |
| JBE/   | Jump if below or equal       | unsigned    | CF = 1 or ZF = 1   |
| JNA    | Jump if not above            |             |                    |
| JA/    | Jump if above                | unsigned    | CF = 0 and ZF = 0  |
| JNBE   | Jump if not below or equal   |             |                    |

And, finally, the signed ones:

|Instr   | Description                  | signed-ness | Flags              |
| JL/    | Jump if less                 | signed      | SF <> OF           |
| JNGE   | Jump if not greater or equal |             |                    |
| JGE/   | Jump if greater or equal     | signed      | SF = OF            |
| JNL    | Jump if not less             |             |                    |
| JLE/   | Jump if less or equal        | signed      | ZF = 1 or SF <> OF |
| JNG    | Jump if not greater          |             |                    |
| JG/    | Jump if greater              | signed      | ZF = 0 and SF = OF |
| JNLE   | Jump if not less or equal    |             |                    |

Is List<Dog> a subclass of List<Animal>? Why are Java generics not implicitly polymorphic?

The problem has been well-identified. But there's a solution; make doSomething generic:

<T extends Animal> void doSomething<List<T> animals) {

now you can call doSomething with either List<Dog> or List<Cat> or List<Animal>.

How can I trigger an onchange event manually?

MDN suggests that there's a much cleaner way of doing this in modern browsers:

// Assuming we're listening for e.g. a 'change' event on `element`

// Create a new 'change' event
var event = new Event('change');

// Dispatch it.

Cleanest way to toggle a boolean variable in Java?

theBoolean ^= true;

Fewer keystrokes if your variable is longer than four letters

Edit: code tends to return useful results when used as Google search terms. The code above doesn't. For those who need it, it's bitwise XOR as described here.

Shortest distance between a point and a line segment

And now my solution as well...... (Javascript)

It is very fast because I try to avoid any Math.pow functions.

As you can see, at the end of the function I have the distance of the line.

code is from the lib!/example

 * Static util function to determine is a point(px,py) on the line(x1,y1,x2,y2)
 * A simple hit test.
 * @return {boolean}
 * @static
 * @private
 * @param {Number} coronaWidth the accepted corona for the hit test
 * @param {Number} X1 x coordinate of the start point of the line
 * @param {Number} Y1 y coordinate of the start point of the line
 * @param {Number} X2 x coordinate of the end point of the line
 * @param {Number} Y2 y coordinate of the end point of the line
 * @param {Number} px x coordinate of the point to test
 * @param {Number} py y coordinate of the point to test
graphiti.shape.basic.Line.hit= function( coronaWidth, X1, Y1,  X2,  Y2, px, py)
  // Adjust vectors relative to X1,Y1
  // X2,Y2 becomes relative vector from X1,Y1 to end of segment
  X2 -= X1;
  Y2 -= Y1;
  // px,py becomes relative vector from X1,Y1 to test point
  px -= X1;
  py -= Y1;
  var dotprod = px * X2 + py * Y2;
  var projlenSq;
  if (dotprod <= 0.0) {
      // px,py is on the side of X1,Y1 away from X2,Y2
      // distance to segment is length of px,py vector
      // "length of its (clipped) projection" is now 0.0
      projlenSq = 0.0;
  } else {
      // switch to backwards vectors relative to X2,Y2
      // X2,Y2 are already the negative of X1,Y1=>X2,Y2
      // to get px,py to be the negative of px,py=>X2,Y2
      // the dot product of two negated vectors is the same
      // as the dot product of the two normal vectors
      px = X2 - px;
      py = Y2 - py;
      dotprod = px * X2 + py * Y2;
      if (dotprod <= 0.0) {
          // px,py is on the side of X2,Y2 away from X1,Y1
          // distance to segment is length of (backwards) px,py vector
          // "length of its (clipped) projection" is now 0.0
          projlenSq = 0.0;
      } else {
          // px,py is between X1,Y1 and X2,Y2
          // dotprod is the length of the px,py vector
          // projected on the X2,Y2=>X1,Y1 vector times the
          // length of the X2,Y2=>X1,Y1 vector
          projlenSq = dotprod * dotprod / (X2 * X2 + Y2 * Y2);
    // Distance to line is now the length of the relative point
    // vector minus the length of its projection onto the line
    // (which is zero if the projection falls outside the range
    //  of the line segment).
    var lenSq = px * px + py * py - projlenSq;
    if (lenSq < 0) {
        lenSq = 0;
    return Math.sqrt(lenSq)<coronaWidth;

How to read from stdin line by line in Node

if you want to ask the user number of lines first:

    //array to save line by line 
    let xInputs = [];

    const getInput = async (resolve)=>{
            const readline = require('readline').createInterface({
                input: process.stdin,
                output: process.stdout,

    const getMultiInput = (numberOfInputLines,callback)=>{
        let i = 0;
        let p = Promise.resolve(); 
        for (; i < numberOfInputLines; i++) {
            p = p.then(_ => new Promise(resolve => getInput(resolve)));

    //get number of lines 
    const readline = require('readline').createInterface({
        input: process.stdin,
        output: process.stdout,
        terminal: false
           //get here the inputs from xinputs array 

How do I remove a single breakpoint with GDB?

You can list breakpoints with:

info break

This will list all breakpoints. Then a breakpoint can be deleted by its corresponding number:

del 3

For example:

 (gdb) info b
 Num     Type           Disp Enb Address    What
  3      breakpoint     keep y   0x004018c3 in timeCorrect at my3.c:215
  4      breakpoint     keep y   0x004295b0 in avi_write_packet atlibavformat/avienc.c:513
 (gdb) del 3
 (gdb) info b
 Num     Type           Disp Enb Address    What
  4      breakpoint     keep y   0x004295b0 in avi_write_packet atlibavformat/avienc.c:513

Export/import jobs in Jenkins

In a web browser visit:


Just save the file to your disk.

How to export JavaScript array info to csv (on client side)?

Simply try this, some of the answers here are not handling unicode data and data that has comma for example date.

function downloadUnicodeCSV(filename, datasource) {
    var content = '', newLine = '\r\n';
    for (var _i = 0, datasource_1 = datasource; _i < datasource_1.length; _i++) {
        var line = datasource_1[_i];
        var i = 0;
        for (var _a = 0, line_1 = line; _a < line_1.length; _a++) {
            var item = line_1[_a];
            var it = item.replace(/"/g, '""');
            if ("|,|\n)/g) >= 0) {
                it = '"' + it + '"';
            content += (i > 0 ? ',' : '') + it;
        content += newLine;
    var link = document.createElement('a');
    link.setAttribute('href', 'data:text/csv;charset=utf-8,%EF%BB%BF' + encodeURIComponent(content));
    link.setAttribute('download', filename); = 'hidden';

Convert string to hex-string in C#

For Unicode support:

public class HexadecimalEncoding
    public static string ToHexString(string str)
        var sb = new StringBuilder();

        var bytes = Encoding.Unicode.GetBytes(str);
        foreach (var t in bytes)

        return sb.ToString(); // returns: "48656C6C6F20776F726C64" for "Hello world"

    public static string FromHexString(string hexString)
        var bytes = new byte[hexString.Length / 2];
        for (var i = 0; i < bytes.Length; i++)
            bytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);

        return Encoding.Unicode.GetString(bytes); // returns: "Hello world" for "48656C6C6F20776F726C64"

New lines inside paragraph in

If you want to be a little bit fancier you can also create it as an html list to create something like bullets or numbers using ul or ol.

<li>Line 1</li>
<li>Line 2</li>

Iterating each character in a string using Python

As Johannes pointed out,

for c in "string":
    #do something with c

You can iterate pretty much anything in python using the for loop construct,

for example, open("file.txt") returns a file object (and opens the file), iterating over it iterates over lines in that file

with open(filename) as f:
    for line in f:
        # do something with line

If that seems like magic, well it kinda is, but the idea behind it is really simple.

There's a simple iterator protocol that can be applied to any kind of object to make the for loop work on it.

Simply implement an iterator that defines a next() method, and implement an __iter__ method on a class to make it iterable. (the __iter__ of course, should return an iterator object, that is, an object that defines next())

See official documentation

How to completely uninstall Android Studio on Mac?

You may also delete gradle file, if you don't use gradle any where else:

rm -Rfv ~/.gradle/

because .gradle folder contains cached artifacts that are no longer needed.

Connect multiple devices to one device via Bluetooth

This is the class where the connection is established and messages are recieved. Make sure to pair the devices before you run the application. If you want to have a slave/master connection, where each slave can only send messages to the master , and the master can broadcast messages to all slaves. You should only pair the master with each slave , but you shouldn't pair the slaves together.

    package com.example.gaby.coordinatorv1;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.Set;
    import java.util.UUID;
    import android.bluetooth.BluetoothAdapter;
    import android.bluetooth.BluetoothDevice;
    import android.bluetooth.BluetoothServerSocket;
    import android.bluetooth.BluetoothSocket;
    import android.content.Context;
    import android.os.Bundle;
    import android.os.Handler;
    import android.os.Message;
    import android.util.Log;
    import android.widget.Toast;

    public class Piconet {

        private final static String TAG = Piconet.class.getSimpleName();

        // Name for the SDP record when creating server socket
        private static final String PICONET = "ANDROID_PICONET_BLUETOOTH";

        private final BluetoothAdapter mBluetoothAdapter;

        // String: device address
        // BluetoothSocket: socket that represent a bluetooth connection
        private HashMap<String, BluetoothSocket> mBtSockets;

        // String: device address
        // Thread: thread for connection
        private HashMap<String, Thread> mBtConnectionThreads;

        private ArrayList<UUID> mUuidList;

        private ArrayList<String> mBtDeviceAddresses;

        private Context context;

        private Handler handler = new Handler() {
            public void handleMessage(Message msg) {
                switch (msg.what) {
                    case 1:
                        Toast.makeText(context, msg.getData().getString("msg"), Toast.LENGTH_SHORT).show();

        public Piconet(Context context) {
            this.context = context;

            mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

            mBtSockets = new HashMap<String, BluetoothSocket>();
            mBtConnectionThreads = new HashMap<String, Thread>();
            mUuidList = new ArrayList<UUID>();
            mBtDeviceAddresses = new ArrayList<String>();

            // Allow up to 7 devices to connect to the server

            Thread connectionProvider = new Thread(new ConnectionProvider());


        public void startPiconet() {
            Log.d(TAG, " -- Looking devices -- ");
            // The devices must be already paired
            Set<BluetoothDevice> pairedDevices = mBluetoothAdapter
            if (pairedDevices.size() > 0) {
                for (BluetoothDevice device : pairedDevices) {
                    // X , Y and Z are the Bluetooth name (ID) for each device you want to connect to
                    if (device != null && (device.getName().equalsIgnoreCase("X") || device.getName().equalsIgnoreCase("Y")
                            || device.getName().equalsIgnoreCase("Z") || device.getName().equalsIgnoreCase("M"))) {
                        Log.d(TAG, " -- Device " + device.getName() + " found --");
                        BluetoothDevice remoteDevice = mBluetoothAdapter
            } else {
                Toast.makeText(context, "No paired devices", Toast.LENGTH_SHORT).show();

        private class ConnectionProvider implements Runnable {
            public void run() {
                try {
                    for (int i=0; i<mUuidList.size(); i++) {
                        BluetoothServerSocket myServerSocket = mBluetoothAdapter
                                .listenUsingRfcommWithServiceRecord(PICONET, mUuidList.get(i));
                        Log.d(TAG, " ** Opened connection for uuid " + i + " ** ");

                        // This is a blocking call and will only return on a
                        // successful connection or an exception
                        Log.d(TAG, " ** Waiting connection for socket " + i + " ** ");
                        BluetoothSocket myBTsocket = myServerSocket.accept();
                        Log.d(TAG, " ** Socket accept for uuid " + i + " ** ");
                        try {
                            // Close the socket now that the
                            // connection has been made.
                        } catch (IOException e) {
                            Log.e(TAG, " ** IOException when trying to close serverSocket ** ");

                        if (myBTsocket != null) {
                            String address = myBTsocket.getRemoteDevice().getAddress();

                            mBtSockets.put(address, myBTsocket);

                            Thread mBtConnectionThread = new Thread(new BluetoohConnection(myBTsocket));

                            Log.i(TAG," ** Adding " + address + " in mBtDeviceAddresses ** ");
                            mBtConnectionThreads.put(address, mBtConnectionThread);
                        } else {
                            Log.e(TAG, " ** Can't establish connection ** ");
                } catch (IOException e) {
                    Log.e(TAG, " ** IOException in ConnectionService:ConnectionProvider ** ", e);

        private class BluetoohConnection implements Runnable {
            private String address;

            private final InputStream mmInStream;

            public BluetoohConnection(BluetoothSocket btSocket) {

                InputStream tmpIn = null;

                try {
                    tmpIn = new DataInputStream(btSocket.getInputStream());
                } catch (IOException e) {
                    Log.e(TAG, " ** IOException on create InputStream object ** ", e);
                mmInStream = tmpIn;
            public void run() {
                byte[] buffer = new byte[1];
                String message = "";
                while (true) {

                    try {
                        int readByte =;
                        if (readByte == -1) {
                            Log.e(TAG, "Discarting message: " + message);
                            message = "";
                        buffer[0] = (byte) readByte;

                        if (readByte == 0) { // see terminateFlag on write method
                            message = "";
                        } else { // a message has been recieved
                            message += new String(buffer, 0, 1);
                    } catch (IOException e) {
                        Log.e(TAG, " ** disconnected ** ", e);


         * @param receiveMessage
        private void onReceive(String receiveMessage) {
            if (receiveMessage != null && receiveMessage.length() > 0) {
                Log.i(TAG, " $$$$ " + receiveMessage + " $$$$ ");
                Bundle bundle = new Bundle();
                bundle.putString("msg", receiveMessage);
                Message message = new Message();
                message.what = 1;

         * @param device
         * @param uuidToTry
         * @return
        private BluetoothSocket getConnectedSocket(BluetoothDevice device, UUID uuidToTry) {
            BluetoothSocket myBtSocket;
            try {
                myBtSocket = device.createRfcommSocketToServiceRecord(uuidToTry);
                return myBtSocket;
            } catch (IOException e) {
                Log.e(TAG, "IOException in getConnectedSocket", e);
            return null;

        private void connect(BluetoothDevice device) {
            BluetoothSocket myBtSocket = null;
            String address = device.getAddress();
            BluetoothDevice remoteDevice = mBluetoothAdapter.getRemoteDevice(address);
            // Try to get connection through all uuids available
            for (int i = 0; i < mUuidList.size() && myBtSocket == null; i++) {
                // Try to get the socket 2 times for each uuid of the list
                for (int j = 0; j < 2 && myBtSocket == null; j++) {
                    Log.d(TAG, " ** Trying connection..." + j + " with " + device.getName() + ", uuid " + i + "...** ");
                    myBtSocket = getConnectedSocket(remoteDevice, mUuidList.get(i));
                    if (myBtSocket == null) {
                        try {
                        } catch (InterruptedException e) {
                            Log.e(TAG, "InterruptedException in connect", e);
            if (myBtSocket == null) {
                Log.e(TAG, " ** Could not connect ** ");
            Log.d(TAG, " ** Connection established with " + device.getName() +"! ** ");
            mBtSockets.put(address, myBtSocket);
            Thread mBluetoohConnectionThread = new Thread(new BluetoohConnection(myBtSocket));
            mBtConnectionThreads.put(address, mBluetoohConnectionThread);


        public void bluetoothBroadcastMessage(String message) {
            //send message to all except Id
            for (int i = 0; i < mBtDeviceAddresses.size(); i++) {
                sendMessage(mBtDeviceAddresses.get(i), message);

        private void sendMessage(String destination, String message) {
            BluetoothSocket myBsock = mBtSockets.get(destination);
            if (myBsock != null) {
                try {
                    OutputStream outStream = myBsock.getOutputStream();
                    final int pieceSize = 16;
                    for (int i = 0; i < message.length(); i += pieceSize) {
                        byte[] send = message.substring(i,
                                Math.min(message.length(), i + pieceSize)).getBytes();
                    // we put at the end of message a character to sinalize that message
                    // was finished
                    byte[] terminateFlag = new byte[1];
                    terminateFlag[0] = 0; // ascii table value NULL (code 0)
                    outStream.write(new byte[1]);
                } catch (IOException e) {
                    Log.d(TAG, "line 278", e);


Your main activity should be as follow :

package com.example.gaby.coordinatorv1;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity {

    private Button discoveryButton;
    private Button messageButton;

    private Piconet piconet;

    public void onCreate(Bundle savedInstanceState) {

        piconet = new Piconet(getApplicationContext());

        messageButton = (Button) findViewById(;
        messageButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                piconet.bluetoothBroadcastMessage("Hello World---*Gaby Bou Tayeh*");

        discoveryButton = (Button) findViewById(;
        discoveryButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {



And here's the XML Layout :

<LinearLayout xmlns:android=""
tools:context=".MainActivity" >


    android:text="Send message"

Do not forget to add the following permissions to your Manifest File :

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

Converting ArrayList to HashMap

Using a supposed name property as the map key:

for (Product p: productList) { s.put(p.getName(), p); }

Creating a new DOM element from an HTML string using built-in DOM methods or Prototype

Note: most current browsers support HTML <template> elements, which provide a more reliable way of turning creating elements from strings. See Mark Amery's answer below for details.

For older browsers, and node/jsdom: (which doesn't yet support <template> elements at the time of writing), use the following method. It's the same thing the libraries use to do to get DOM elements from an HTML string (with some extra work for IE to work around bugs with its implementation of innerHTML):

function createElementFromHTML(htmlString) {
  var div = document.createElement('div');
  div.innerHTML = htmlString.trim();

  // Change this to div.childNodes to support multiple top-level nodes
  return div.firstChild; 

Note that unlike HTML templates this won't work for some elements that cannot legally be children of a <div>, such as <td>s.

If you're already using a library, I would recommend you stick to the library-approved method of creating elements from HTML strings:

"ssl module in Python is not available" when installing package with pip3

On macos, configure python 3.8.1 with the command below will solve the problem, i think it would also work on Linux.

./configure --enable-optimizations --with-openssl=/usr/local/opt/[email protected]/

change the dir parameter based on your system.

How to check if number is divisible by a certain number?

n % x == 0

Means that n can be divided by x. So... for instance, in your case:

boolean isDivisibleBy20 = number % 20 == 0;

Also, if you want to check whether a number is even or odd (whether it is divisible by 2 or not), you can use a bitwise operator:

boolean even = (number & 1) == 0;
boolean odd  = (number & 1) != 0;

AssertNull should be used or AssertNotNull

Use assertNotNull(obj). assert means must be.

The program can’t start because MSVCR71.dll is missing from your computer. Try reinstalling the program to fix this program

I found this error occurred when I was using the wrong version of Java. When I changed my environment from Java 7 down to Java 6 the error no longer appeared.

(The MSVCR71.DLL file is in the JDK 6 bin directory, where JDK 7 has MSVCR100.DLL.)

Count the number of occurrences of a string in a VARCHAR field?

Here is a function that will do that.

CREATE FUNCTION count_str(haystack TEXT, needle VARCHAR(32))
    RETURN ROUND((CHAR_LENGTH(haystack) - CHAR_LENGTH(REPLACE(haystack, needle, ""))) / CHAR_LENGTH(needle));

How to reload apache configuration for a site without restarting apache?

If you are using Ubuntu server, you can use systemctl

systemctl reload apache2

How to handle AccessViolationException

In .NET 4.0, the runtime handles certain exceptions raised as Windows Structured Error Handling (SEH) errors as indicators of Corrupted State. These Corrupted State Exceptions (CSE) are not allowed to be caught by your standard managed code. I won't get into the why's or how's here. Read this article about CSE's in the .NET 4.0 Framework:

But there is hope. There are a few ways to get around this:

  1. Recompile as a .NET 3.5 assembly and run it in .NET 4.0.

  2. Add a line to your application's config file under the configuration/runtime element: <legacyCorruptedStateExceptionsPolicy enabled="true|false"/>

  3. Decorate the methods you want to catch these exceptions in with the HandleProcessCorruptedStateExceptions attribute. See for details.


Previously, I referenced a forum post for additional details. But since Microsoft Connect has been retired, here are the additional details in case you're interested:

From Gaurav Khanna, a developer from the Microsoft CLR Team

This behaviour is by design due to a feature of CLR 4.0 called Corrupted State Exceptions. Simply put, managed code shouldnt make an attempt to catch exceptions that indicate corrupted process state and AV is one of them.

He then goes on to reference the documentation on the HandleProcessCorruptedStateExceptionsAttribute and the above article. Suffice to say, it's definitely worth a read if you're considering catching these types of exceptions.

scale Image in an UIButton to AspectFit?

Background image can actually be set to scale aspect fill pretty easily. Just need to do something like this in a subclass of UIButton:

- (CGRect)backgroundRectForBounds:(CGRect)bounds
    // you'll need the original size of the image, you 
    // can save it from setBackgroundImage:forControlState
    return CGRectFitToFillRect(__original_image_frame_size__, bounds);

// Utility function, can be saved elsewhere
CGRect CGRectFitToFillRect( CGRect inRect, CGRect maxRect )
    CGFloat origRes = inRect.size.width / inRect.size.height;
    CGFloat newRes = maxRect.size.width / maxRect.size.height;

    CGRect retRect = maxRect;

    if (newRes < origRes)
        retRect.size.width = inRect.size.width * maxRect.size.height / inRect.size.height;
        retRect.origin.x = roundf((maxRect.size.width - retRect.size.width) / 2);
        retRect.size.height = inRect.size.height * maxRect.size.width / inRect.size.width;
        retRect.origin.y = roundf((maxRect.size.height - retRect.size.height) / 2);

    return retRect;

How can I remove the top and right axis in matplotlib?

Library Seaborn has this built in with function .despine().

Just add:

import seaborn as sns

Now create your graph. And add at the end:


If you look at some of the default parameter values of the function it removes the top and right spine and keeps the bottom and left spine:

sns.despine(top=True, right=True, left=False, bottom=False)

Check out further documentation here:

Access PHP variable in JavaScript

You can't, you'll have to do something like

<script type="text/javascript">
   var php_var = "<?php echo $php_var; ?>";

You can also load it with AJAX

rhino is right, the snippet lacks of a type for the sake of brevity.

Also, note that if $php_var has quotes, it will break your script. You shall use addslashes, htmlentities or a custom function.

Is Visual Studio Community a 30 day trial?

For my case the problem was in fact that i broke machine.config and looks like VS couldn't have a connection I've added the following lines to my machine.config

  <proxy autoDetect="false" bypassonlocal="false" proxyaddress="" usesystemdefault="false" />

After replacing the previous section to:

  <proxy autoDetect="false" bypassonlocal="false" proxyaddress="" usesystemdefault="false" />

VS started to work.

JS: Failed to execute 'getComputedStyle' on 'Window': parameter is not of type 'Element'

For those who got this error in AngularJS and not jQuery:

I got it in AngularJS v1.5.8 by trying to ng-include a type="text/ng-template" that didn't exist.

 <div ng-include="tab.content">...</div>

Make sure that when you use ng-include, the data for that directive points to an actual page/section. Otherwise, you probably wanted:


How to handle query parameters in angular 2

The simple way to do that in Angular 7+ is to:

Define a path in your ?-routing.module.ts

{ path: '/yourpage', component: component-name }

Import the ActivateRoute and Router module in your component and inject them in the constructor

contructor(private route: ActivateRoute, private router: Router){ ... }

Subscribe the ActivateRoute to the ngOnInit

ngOnInit() {

    this.route.queryParams.subscribe(params => {
      // {page: '2' }

Provide it to a link:

<a [routerLink]="['/yourpage']" [queryParams]="{ page: 2 }">2</a>

What's the actual use of 'fail' in JUnit test case?

In concurrent and/or asynchronous settings, you may want to verify that certain methods (e.g. delegates, event listeners, response handlers, you name it) are not called. Mocking frameworks aside, you can call fail() in those methods to fail the tests. Expired timeouts are another natural failure condition in such scenarios.

For example:

final CountDownLatch latch = new CountDownLatch(1);

service.asyncCall(someParameter, new ResponseHandler<SomeType>() {
    public void onSuccess(SomeType result) {
        // Further test assertions on the result

    public void onError(Exception e) {

if ( !latch.await(5, TimeUnit.SECONDS) ) {
    fail("No response after 5s");

Cannot find firefox binary in PATH. Make sure firefox is installed. OS appears to be: VISTA

File pathBinary = new File("Firefox.exe location");
FirefoxBinary ffBinary = new FirefoxBinary(pathBinary);
FirefoxProfile firefoxProfile = new FirefoxProfile();
FirefoxDriver driver = new FirefoxDriver(ffBinary,firefoxProfile);

You need to add binary of the browser


Best and forever solution: Just add Firefox.exe location to environmental variables

$location / switching between html5 and hashbang mode / link rewriting

Fur future readers, if you are using Angular 1.6, you also need to change the hashPrefix:

appModule.config(['$locationProvider', function($locationProvider) {

Don't forget to set the base in your HTML <head>:

    <base href="/">

More info about the changelog here.

Simulate a click on 'a' element using javascript/jquery

Use this code to click:


PHP, MySQL error: Column count doesn't match value count at row 1

You have 9 fields listed, but only 8 values. Try adding the method.

How to convert nanoseconds to seconds using the TimeUnit enum?

You should write :

    long startTime = System.nanoTime();        
    long estimatedTime = System.nanoTime() - startTime;

Assigning the endTime in a variable might cause a few nanoseconds. In this approach you will get the exact elapsed time.

And then:

TimeUnit.SECONDS.convert(estimatedTime, TimeUnit.NANOSECONDS)

Maven 3 warnings about build.plugins.plugin.version

Add a <version> element after the <plugin> <artifactId> in your pom.xml file. Find the following text:


Add the version tag to it:


The warning should be resolved.

Regarding this:

'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing

Many people have mentioned why the issue is happening, but fail to suggest a fix. All I needed to do was to go into my POM file for my project, and add the <version> tag as shown above.

To discover the version number, one way is to look in Maven's output after it finishes running. Where you are missing version numbers, Maven will display its default version:

[INFO] --- maven-compiler-plugin:2.3.2:compile (default-compile) @ entities ---

Take that version number (as in the 2.3.2 above) and add it to your POM, as shown.

Find the location of a character in string

Here's another straightforward alternative.

> which(strsplit(string, "")[[1]]=="2")
[1]  4 24

How to grep Git commit diffs or contents for a certain word?

One more way/syntax to do it is: git log -S "word"
Like this you can search for example git log -S "with whitespaces and stuff @/#ü !"

need to add a class to an element

You probably need something like:

result.className = 'red'; 

In pure JavaScript you should use className to deal with classes. jQuery has an abstraction called addClass for it.

How to click a link whose href has a certain substring in Selenium?

You can do this:

//first get all the <a> elements
List<WebElement> linkList=driver.findElements(By.tagName("a"));

//now traverse over the list and check
for(int i=0 ; i<linkList.size() ; i++)

in this what we r doing is first we are finding all the <a> tags and storing them in a list.After that we are iterating the list one by one to find <a> tag whose href attribute contains long string. And then we click on that particular <a> tag and comes out of the loop.

How to pass arguments from command line to gradle

I have written a piece of code that puts the command line arguments in the format that gradle expects.

// this method creates a command line arguments
def setCommandLineArguments(commandLineArgs) {
    // remove spaces 
    def arguments = commandLineArgs.tokenize()

            // create a string that can be used by Eval 
            def cla = "["
            // go through the list to get each argument
            arguments.each {
                    cla += "'" + "${it}" + "',"

    // remove last "," add "]" and set the args 
    return cla.substring(0, cla.lastIndexOf(',')) + "]"

my task looks like this:

task runProgram(type: JavaExec) {
    if ( project.hasProperty("commandLineArgs") ) {
            args setCommandLineArguments(commandLineArgs) )

To pass the arguments from the command line you run this:

gradle runProgram -PcommandLineArgs="arg1 arg2 arg3 arg4"    

How to properly use jsPDF library

Shouldn't you also be using the jspdf.plugin.from_html.js library? Besides the main library (jspdf.js), you must use other libraries for "special operations" (like jspdf.plugin.addimage.js for using images). Check

"Submit is not a function" error in JavaScript

<form action="product.php" method="post" name="frmProduct" id="frmProduct" enctype="multipart/form-data">

<input id="submit_value" type="button" name="submit_value" value="">


<script type="text/javascript">

document.getElementById("submit_value").onclick = submitAction;

function submitAction()
    return false;

EDIT: I accidentally swapped the id's around

How do I find the last column with data?

I think we can modify the UsedRange code from @Readify's answer above to get the last used column even if the starting columns are blank or not.

So this lColumn = ws.UsedRange.Columns.Count modified to

this lColumn = ws.UsedRange.Column + ws.UsedRange.Columns.Count - 1 will give reliable results always

enter image description here

?Sheet1.UsedRange.Column + Sheet1.UsedRange.Columns.Count - 1

Above line Yields 9 in the immediate window.

Get element type with jQuery

Getting the element type the jQuery way:

var elementType = $(this).prev().prop('nodeName');

doing the same without jQuery

var elementType = this.previousSibling.nodeName;

Checking for specific element type:

var is_element_input = $(this).prev().is("input"); //true or false