Programs & Examples On #Applicationsettingsbase

How do I plot only a table in Matplotlib?

You can di this:

#axs[1].plot(clust_data[:,0],clust_data[:,1]) # Remove this if you don't need it
axs[1].axis("off")  # This will leave the table alone in the window 

Is there a way to collapse all code blocks in Eclipse?

Shortcuts that worked for me in Versions Oxygen.2 Release (PHP/WINDOWS 7) were

  1. Collapse all code blocks: CTRL + SHIFT + NUMPAD_DIVIDE
  2. Expand all code blocks : CTRL + NUMPAD_MULTIPLY

Reset select value to default

This code will help you out.

    <script type="text/JavaScript" src="jquery-2.0.2.min.js"></script>
    <script type="text/JavaScript">
            var defaultValue = $("#my_select").val();
            $("#reset").click(function () {
    <select id="my_select">
        <option value="a">a</option>
        <option value="b" selected="selected">b</option>
        <option value="c">c</option>
    <div id="reset">
        <input type="button" value="reset"/>

What's the right way to decode a string that has special HTML entities in it?

This is my favourite way of decoding HTML characters. The advantage of using this code is that tags are also preserved.

function decodeHtml(html) {
    var txt = document.createElement("textarea");
    txt.innerHTML = html;
    return txt.value;



Entity:&nbsp;Bad attempt at XSS:<script>alert('new\nline?')</script><br>


Entity: Bad attempt at XSS:<script>alert('new\nline?')</script><br>

How to get screen width and height

Alternative way using function

private int[] getScreenSIze(){
        DisplayMetrics displaymetrics = new DisplayMetrics();
        int h = displaymetrics.heightPixels;
        int w = displaymetrics.widthPixels;

        int[] size={w,h};
        return size;


on button click or on your create function add the following code

int[] screenSize= getScreenSIze();
        int width=screenSize[0];
        int height=screenSize[1];
        screenSizes.setText("Phone Screen sizes \n\n  width = "+width+" \n Height = "+height);

See demo source code

Launching Spring application Address already in use

You have another process that’s listening on port 8080 which is the default port that’s used by Spring Boot’s web support. You either need to stop that process or configure your app to listen on another port.

You can change the port configuration by adding server.port=4040 (for example) to src/main/resources/

How to execute .sql file using powershell?

Here is a function that I have in my PowerShell profile for loading SQL snapins:

function Load-SQL-Server-Snap-Ins

        if (!(Test-Path $sqlpsreg -ErrorAction "SilentlyContinue"))
            throw "SQL Server Powershell is not installed yet (part of SQLServer installation)."

        $item = Get-ItemProperty $sqlpsreg
        $sqlpsPath = [System.IO.Path]::GetDirectoryName($item.Path)

        $assemblyList = @(
            "Microsoft.SqlServer.ConnectionInfo ",

        foreach ($assembly in $assemblyList)
            $assembly = [System.Reflection.Assembly]::LoadWithPartialName($assembly) 
            if ($assembly -eq $null)
                { Write-Host "`t`t($MyInvocation.InvocationName): Could not load $assembly" }

        Set-Variable -scope Global -name SqlServerMaximumChildItems -Value 0
        Set-Variable -scope Global -name SqlServerConnectionTimeout -Value 30
        Set-Variable -scope Global -name SqlServerIncludeSystemObjects -Value $false
        Set-Variable -scope Global -name SqlServerMaximumTabCompletion -Value 1000


         if ((Get-PSSnapin -Name SqlServerProviderSnapin100 -ErrorAction SilentlyContinue) -eq $null) 
            cd $sqlpsPath

            Add-PsSnapin SqlServerProviderSnapin100 -ErrorAction Stop
            Add-PsSnapin SqlServerCmdletSnapin100 -ErrorAction Stop
            Update-TypeData -PrependPath SQLProvider.Types.ps1xml
            Update-FormatData -PrependPath SQLProvider.Format.ps1xml

        Write-Host "`t`t$($MyInvocation.InvocationName): $_" 


Stored procedure or function expects parameter which is not supplied

in my case, I was passing all the parameters but one of the parameter my code was passing a null value for string.

Eg: cmd.Parameters.AddWithValue("@userName", userName);

in the above case, if the data type of userName is string, I was passing userName as null.

How can I beautify JSON programmatically?

Here's something that might be interesting for developers hacking (minified or obfuscated) JavaScript more frequently.

You can build your own CLI JavaScript beautifier in under 5 mins and have it handy on the command-line. You'll need Mozilla Rhino, JavaScript file of some of the JS beautifiers available online, small hack and a script file to wrap it all up.

I wrote an article explaining the procedure: Command-line JavaScript beautifier implemented in JavaScript.

JavaScript vs for

Note that the native Array.forEach method is now widely supported.

AngularJS sorting rows by table header

Use a third-party JavaScript library. It will give you that and much more. A good example is datatables (if you are also using jQuery):

Or just order your bound array in $scope.results when the header is clicked.

How can I uninstall Ruby on ubuntu?

Run the following command on the terminal:

sudo apt-get autoremove ruby

How to embed image or picture in jupyter notebook, either from a local machine or from a web resource?

Alternatively, you can use a plain HTML <img src>, which allows you to change height and width and is still read by the markdown interpreter:

<img src="subdirectory/MyImage.png" width=60 height=60 />

What is the easiest way to initialize a std::vector with hardcoded elements?

If the array is:

int arr[] = {1, 2, 3};
int len = (sizeof(arr)/sizeof(arr[0])); // finding length of array
vector < int > v;
std:: v.assign(arr, arr+len); // assigning elements from array to vector 

Oracle SQL - REGEXP_LIKE contains characters other than a-z or A-Z

Something like

select *
  from foo
 where regexp_like( col1, '[^[:alpha:]]' ) ;

should work

SQL> create table foo( col1 varchar2(100) );

Table created.

SQL> insert into foo values( 'abc' );

1 row created.

SQL> insert into foo values( 'abc123' );

1 row created.

SQL> insert into foo values( 'def' );

1 row created.

SQL> select *
  2    from foo
  3   where regexp_like( col1, '[^[:alpha:]]' ) ;


Formatting text in a TextBlock

You can do this in XAML easily enough:

  Hello <Bold>my</Bold> faithful <Underline>computer</Underline>.<Italic>You rock!</Italic>

Which Ruby version am I really running?

Run this command:

rvm get stable --auto-dotfiles

and make sure to read all the output. RVM will tell you if something is wrong, which in your case might be because GEM_HOME is set to something different then PATH.

What's the difference between "Write-Host", "Write-Output", or "[console]::WriteLine"?

Here's another way to accomplish the equivalent of Write-Output. Just put your string in quotes:


You can make sure this works the same as Write-Output by running this experiment:

"blah blah" > out.txt

Write-Output "blah blah" > out.txt

Write-Host "blah blah" > out.txt

The first two will output "blah blah" to out.txt, but the third one won't.

"help Write-Output" gives a hint of this behavior:

This cmdlet is typically used in scripts to display strings and other objects on the console. However, because the default behavior is to display the objects at the end of a pipeline, it is generally not necessary to use the cmdlet.

In this case, the string itself "count=$count" is the object at the end of a pipeline, and is displayed.

Wrap a text within only two lines inside div

@Asiddeen bn Muhammad's solution worked for me with a little modification to the css

    .text {
 line-height: 1.5;
  height: 6em; 
white-space: normal;
overflow: hidden;
text-overflow: ellipsis;
display: block;
-webkit-line-clamp: 2;
-webkit-box-orient: vertical;

Windows XP or later Windows: How can I run a batch file in the background with no window displayed?

Do you need the second batch file to run asynchronously? Typically one batch file runs another synchronously with the call command, and the second one would share the first one's window.

You can use start /b second.bat to launch a second batch file asynchronously from your first that shares your first one's window. If both batch files write to the console simultaneously, the output will be overlapped and probably indecipherable. Also, you'll want to put an exit command at the end of your second batch file, or you'll be within a second cmd shell once everything is done.

Loop through all the resources in a .resx file

If you want to use LINQ, use resourceSet.OfType<DictionaryEntry>(). Using LINQ allows you, for example, to select resources based on their index (int) instead of key (string):

ResourceSet resourceSet = Resources.ResourceManager.GetResourceSet(CultureInfo.CurrentUICulture, true, true);
foreach (var entry in resourceSet.OfType<DictionaryEntry>().Select((item, i) => new { Index = i, Key = item.Key, Value = item.Value }))
    Console.WriteLine(@"[{0}] {1}", entry.Index, entry.Key);

How to explain callbacks in plain english? How are they different from calling one function from another function?

“In computer programming, a callback is a reference to executable code, or a piece of executable code, that is passed as an argument to other code. This allows a lower-level software layer to call a subroutine (or function) defined in a higher-level layer.” - Wikipedia

Callback in C using Function Pointer

In C, callback is implemented using Function Pointer. Function Pointer - as the name suggests, is a pointer to a function.

For example, int (*ptrFunc) ();

Here, ptrFunc is a pointer to a function that takes no arguments and returns an integer. DO NOT forget to put in the parenthesis, otherwise the compiler will assume that ptrFunc is a normal function name, which takes nothing and returns a pointer to an integer.

Here is some code to demonstrate the function pointer.

int func(int, int);
int main(void)
    int result1,result2;
    /* declaring a pointer to a function which takes
       two int arguments and returns an integer as result */
    int (*ptrFunc)(int,int);

    /* assigning ptrFunc to func's address */                    

    /* calling func() through explicit dereference */
    result1 = (*ptrFunc)(10,20);

    /* calling func() through implicit dereference */        
    result2 = ptrFunc(10,20);            
    printf("result1 = %d result2 = %d\n",result1,result2);
    return 0;

int func(int x, int y)
    return x+y;

Now let us try to understand the concept of Callback in C using function pointer.

The complete program has three files: callback.c, reg_callback.h and reg_callback.c.

/* callback.c */

/* callback function definition goes here */
void my_callback(void)
    printf("inside my_callback\n");

int main(void)
    /* initialize function pointer to
    my_callback */
    callback ptr_my_callback=my_callback;                        
    printf("This is a program demonstrating function callback\n");
    /* register our callback function */
    printf("back inside main program\n");
    return 0;

/* reg_callback.h */
typedef void (*callback)(void);
void register_callback(callback ptr_reg_callback);

/* reg_callback.c */

/* registration goes here */
void register_callback(callback ptr_reg_callback)
    printf("inside register_callback\n");
    /* calling our callback function my_callback */

If we run this program, the output will be

This is a program demonstrating function callback inside register_callback inside my_callback back inside main program

The higher layer function calls a lower layer function as a normal call and the callback mechanism allows the lower layer function to call the higher layer function through a pointer to a callback function.

Callback in Java Using Interface

Java does not have the concept of function pointer It implements Callback mechanism through its Interface mechanism Here instead of a function pointer, we declare an Interface having a method which will be called when the callee finishes its task

Let me demonstrate it through an example:

The Callback Interface

public interface Callback
    public void notify(Result result);

The Caller or the Higher Level Class

public Class Caller implements Callback
Callee ce = new Callee(this); //pass self to the callee

//Other functionality
//Call the Asynctask

public void notify(Result result){
//Got the result after the callee has finished the task
//Can do whatever i want with the result

The Callee or the lower layer function

public Class Callee {
Callback cb;
Callee(Callback cb){
this.cb = cb;

//do the long running task
//get the result
cb.notify(result);//after the task is completed, notify the caller

Callback Using EventListener pattern

  • List item

This pattern is used to notify 0 to n numbers of Observers/Listeners that a particular task has finished

  • List item

The difference between Callback mechanism and EventListener/Observer mechanism is that in callback, the callee notifies the single caller, whereas in Eventlisener/Observer, the callee can notify anyone who is interested in that event (the notification may go to some other parts of the application which has not triggered the task)

Let me explain it through an example.

The Event Interface

public interface Events {

public void clickEvent();
public void longClickEvent();

Class Widget


import java.util.ArrayList;
import java.util.Iterator;

public class Widget implements Events{

    ArrayList<OnClickEventListener> mClickEventListener = new ArrayList<OnClickEventListener>(); 
    ArrayList<OnLongClickEventListener> mLongClickEventListener = new ArrayList<OnLongClickEventListener>();

    public void clickEvent() {
        // TODO Auto-generated method stub
        Iterator<OnClickEventListener> it = mClickEventListener.iterator();
                    OnClickEventListener li =;
    public void longClickEvent() {
        // TODO Auto-generated method stub
        Iterator<OnLongClickEventListener> it = mLongClickEventListener.iterator();
            OnLongClickEventListener li =;


    public interface OnClickEventListener
        public void onClick (Widget source);

    public interface OnLongClickEventListener
        public void onLongClick (Widget source);

    public void setOnClickEventListner(OnClickEventListener li){
    public void setOnLongClickEventListner(OnLongClickEventListener li){

Class Button

public class Button extends Widget{
private String mButtonText;
public Button (){
public String getButtonText() {
return mButtonText;
public void setButtonText(String buttonText) {
this.mButtonText = buttonText;

Class Checkbox

public class CheckBox extends Widget{
private boolean checked;
public CheckBox() {
checked = false;
public boolean isChecked(){
return (checked == true);
public void setCheck(boolean checked){
this.checked = checked;

Activity Class


public class Activity implements Widget.OnClickEventListener
    public Button mButton;
    public CheckBox mCheckBox;
    private static Activity mActivityHandler;
    public static Activity getActivityHandle(){
        return mActivityHandler;
    public Activity ()
        mActivityHandler = this;
        mButton = new Button();
        mCheckBox = new CheckBox();
    public void onClick (Widget source)
        if(source == mButton){
            mButton.setButtonText("Thank you for clicking me...");
            System.out.println(((Button) mButton).getButtonText());
        if(source == mCheckBox){
                System.out.println("The checkbox is checked...");
                System.out.println("The checkbox is not checked...");
    public void doSomeWork(Widget source){

Other Class

public class OtherClass implements Widget.OnClickEventListener{
Button mButton;
public OtherClass(){
mButton = Activity.getActivityHandle().mButton;
mButton.setOnClickEventListner(this);//interested in the click event                        //of the button
public void onClick(Widget source) {
if(source == mButton){
System.out.println("Other Class has also received the event notification...");

Main Class

public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Activity a = new Activity();
OtherClass o = new OtherClass();

As you can see from the above code, that we have an interface called events which basically lists all the events that may happen for our application. The Widget class is the base class for all the UI components like Button, Checkbox. These UI components are the objects that actually receive the events from the framework code. Widget class implements the Events interface and also it has two nested interfaces namely OnClickEventListener & OnLongClickEventListener

These two interfaces are responsible for listening to events that may occur on the Widget derived UI components like Button or Checkbox. So if we compare this example with the earlier Callback example using Java Interface, these two interfaces work as the Callback interface. So the higher level code (Here Activity) implements these two interfaces. And whenever an event occurs to a widget, the higher level code (or the method of these interfaces implemented in the higher level code, which is here Activity) will be called.

Now let me discuss the basic difference between Callback and Eventlistener pattern. As we have mentioned that using Callback, the Callee can notify only a single Caller. But in the case of EventListener pattern, any other part or class of the Application can register for the events that may occur on the Button or Checkbox. The example of this kind of class is the OtherClass. If you see the code of the OtherClass, you will find that it has registered itself as a listener to the ClickEvent that may occur in the Button defined in the Activity. Interesting part is that, besides the Activity ( the Caller), this OtherClass will also be notified whenever the click event occurs on the Button.

How to: Add/Remove Class on mouseOver/mouseOut - JQuery .hover?

You are missing the dot on the selector, and you can use toggleClass method on jquery:

  function () {

Install msi with msiexec in a Specific Directory

Use INSTALLLOCATION. When you have problems, use the /lv log.txt to dump verbose logs. The logs would tell you if there is a property change that would override your own options. If you already installed the product, then a second run might just update it without changing the install location. You will have to uninstall first (use the /x option).

Why is the <center> tag deprecated in HTML?

It's intended that markup, i.e. the HTML tags, represent meaning and structure, not appearance. It was badly mixed up in early versions of HTML but the standards people are trying to clean that up now.

One problem with letting tags control appearance is that your pages don't play well with devices for the handicapped, such as screen readers. It also leads to having lots and lots of tags in your text that don't help clarify the meaning, but rather clutter it with information of a different level.

So CSS was thought up to move formatting/display to a different language, which is separate from the text and can easily be kept that way. Among other things, this allows switching stylesheets to change the appearance of a Web page without touching the other markup. And to be able to do that for lots of pages in one swell foop.

The tools CSS gives you to do this are not always elegant, I'm on your side there. For instance, there is no way to do effective vertical centering. And horizontal centering, if it's not just text amenable to text-align, is not much better.

You have the choice of doing easy, effective and muddled or clean, elegant and cumbersome. I don't understand why Web developers put up with this mess, but I guess they're happy to have at least a chance to get their stuff done.

How to keep :active css style after clicking an element

You can use a little bit of Javascript to add and remove CSS classes of your navitems. For starters, create a CSS class that you're going to apply to the active element, name it ie: ".activeItem". Then, put a javascript function to each of your navigation buttons' onclick event which is going to add "activeItem" class to the one activated, and remove from the others...

It should look something like this: (untested!)

/*In your stylesheet*/
   background-color:#999; /*make some difference for the active item here */

/*In your javascript*/
var prevItem = null;
function activateItem(t){
   if(prevItem != null){
      prevItem.className = prevItem.className.replace(/{\b}?activeItem/, "");
   t.className += " activeItem";
   prevItem = t;

<!-- And then your markup -->
<div id='nav'>
<a href='#abouts' onClick="activateItem(this)">
<div class='navitem about'>
<a href='#workss' onClick="activateItem(this)">
<div class='navitem works'>

python location on mac osx

On High Sierra

which python

shows the default python but if you downloaded and installed the latest version from you can find it by:

which python3.6

which on my machine shows


Finding all the subsets of a set

here is my recursive solution.

vector<vector<int> > getSubsets(vector<int> a){

//base case
    //if there is just one item then its subsets are that item and empty item
    //for example all subsets of {1} are {1}, {}

    if(a.size() == 1){
        vector<vector<int> > temp;

        vector<int> b;

        return temp;


         //here is what i am doing

         // getSubsets({1, 2, 3})
         //without = getSubsets({1, 2})
         //without = {1}, {2}, {}, {1, 2}

         //with = {1, 3}, {2, 3}, {3}, {1, 2, 3}

         //total = {{1}, {2}, {}, {1, 2}, {1, 3}, {2, 3}, {3}, {1, 2, 3}}

         //return total

        int last = a[a.size() - 1];


        vector<vector<int> > without = getSubsets(a);

        vector<vector<int> > with = without;

        for(int i=0;i<without.size();i++){



        vector<vector<int> > total;

        for(int j=0;j<without.size();j++){

        for(int k=0;k<with.size();k++){

        return total;


Get the current fragment object

You can create field in your parent Activity Class:

public class MainActivity extends AppCompatActivity {

    public Fragment fr;

    protected void onCreate(Bundle savedInstanceState) {


And then inside each fragment class:

public class SomeFragment extends Fragment {

    public View onCreateView(LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {

        ((MainActivity) getActivity()).fr = this;

Your 'fr' field is current fragment Object

It's working also with popBackStack()

Calculate relative time in C#

I thought I'd give this a shot using classes and polymorphism. I had a previous iteration which used sub-classing which ended up having way too much overhead. I've switched to a more flexible delegate / public property object model which is significantly better. My code is very slightly more accurate, I wish I could come up with a better way to generate "months ago" that didn't seem too over-engineered.

I think I'd still stick with Jeff's if-then cascade because it's less code and it's simpler (it's definitely easier to ensure it'll work as expected).

For the below code PrintRelativeTime.GetRelativeTimeMessage(TimeSpan ago) returns the relative time message (e.g. "yesterday").

public class RelativeTimeRange : IComparable
    public TimeSpan UpperBound { get; set; }

    public delegate string RelativeTimeTextDelegate(TimeSpan timeDelta);

    public RelativeTimeTextDelegate MessageCreator { get; set; }

    public int CompareTo(object obj)
        if (!(obj is RelativeTimeRange))
            return 1;
        // note that this sorts in reverse order to the way you'd expect, 
        // this saves having to reverse a list later
        return (obj as RelativeTimeRange).UpperBound.CompareTo(UpperBound);

public class PrintRelativeTime
    private static List<RelativeTimeRange> timeRanges;

    static PrintRelativeTime()
        timeRanges = new List<RelativeTimeRange>{
            new RelativeTimeRange
                UpperBound = TimeSpan.FromSeconds(1),
                MessageCreator = (delta) => 
                { return "one second ago"; }
            new RelativeTimeRange
                UpperBound = TimeSpan.FromSeconds(60),
                MessageCreator = (delta) => 
                { return delta.Seconds + " seconds ago"; }

            new RelativeTimeRange
                UpperBound = TimeSpan.FromMinutes(2),
                MessageCreator = (delta) => 
                { return "one minute ago"; }
            new RelativeTimeRange
                UpperBound = TimeSpan.FromMinutes(60),
                MessageCreator = (delta) => 
                { return delta.Minutes + " minutes ago"; }
            new RelativeTimeRange
                UpperBound = TimeSpan.FromHours(2),
                MessageCreator = (delta) => 
                { return "one hour ago"; }
            new RelativeTimeRange
                UpperBound = TimeSpan.FromHours(24),
                MessageCreator = (delta) => 
                { return delta.Hours + " hours ago"; }
            new RelativeTimeRange
                UpperBound = TimeSpan.FromDays(2),
                MessageCreator = (delta) => 
                { return "yesterday"; }
            new RelativeTimeRange
                UpperBound = DateTime.Now.Subtract(DateTime.Now.AddMonths(-1)),
                MessageCreator = (delta) => 
                { return delta.Days + " days ago"; }
            new RelativeTimeRange
                UpperBound = DateTime.Now.Subtract(DateTime.Now.AddMonths(-2)),
                MessageCreator = (delta) => 
                { return "one month ago"; }
            new RelativeTimeRange
                UpperBound = DateTime.Now.Subtract(DateTime.Now.AddYears(-1)),
                MessageCreator = (delta) => 
                { return (int)Math.Floor(delta.TotalDays / 30) + " months ago"; }
            new RelativeTimeRange
                UpperBound = DateTime.Now.Subtract(DateTime.Now.AddYears(-2)),
                MessageCreator = (delta) => 
                { return "one year ago"; }
            new RelativeTimeRange
                UpperBound = TimeSpan.MaxValue,
                MessageCreator = (delta) => 
                { return (int)Math.Floor(delta.TotalDays / 365.24D) + " years ago"; }


    public static string GetRelativeTimeMessage(TimeSpan ago)
        RelativeTimeRange postRelativeDateRange = timeRanges[0];

        foreach (var timeRange in timeRanges)
            if (ago.CompareTo(timeRange.UpperBound) <= 0)
                postRelativeDateRange = timeRange;

        return postRelativeDateRange.MessageCreator(ago);

Outputting data from unit test in Python

Another option - start a debugger where the test fails.

Try running your tests with Testoob (it will run your unittest suite without changes), and you can use the '--debug' command line switch to open a debugger when a test fails.

Here's a terminal session on windows:

C:\work> testoob --debug
Debugging for failure in test: test_foo (tests.MyTests.test_foo)
> c:\python25\lib\
-> (msg or '%r != %r' % (first, second))
(Pdb) up
> c:\work\
-> self.assertEqual(x, y)
(Pdb) l
  1     from unittest import TestCase
  2     class MyTests(TestCase):
  3       def test_foo(self):
  4         x = 1
  5         y = 2
  6  ->     self.assertEqual(x, y)

How do I get a specific range of numbers from rand()?

I think the following does it semi right. It's been awhile since I've touched C. The idea is to use division since modulus doesn't always give random results. I added 1 to RAND_MAX since there are that many possible values coming from rand including 0. And since the range is also 0 inclusive, I added 1 there too. I think the math is arranged correctly avoid integer math problems.

#define MK_DIVISOR(max) ((int)((unsigned int)RAND_MAX+1/(max+1)))

num = rand()/MK_DIVISOR(65);

Calculate compass bearing / heading to location in Android

Ok I figured this out. For anyone else trying to do this you need:

a) heading: your heading from the hardware compass. This is in degrees east of magnetic north

b) bearing: the bearing from your location to the destination location. This is in degrees east of true north.


c) declination: the difference between true north and magnetic north

The heading that is returned from the magnetometer + accelermometer is in degrees east of true (magnetic) north (-180 to +180) so you need to get the difference between north and magnetic north for your location. This difference is variable depending where you are on earth. You can obtain by using GeomagneticField class.

GeomagneticField geoField;

private final LocationListener locationListener = new LocationListener() {
   public void onLocationChanged(Location location) {
      geoField = new GeomagneticField(

Armed with these you calculate the angle of the arrow to draw on your map to show where you are facing in relation to your destination object rather than true north.

First adjust your heading with the declination:

heading += geoField.getDeclination();

Second, you need to offset the direction in which the phone is facing (heading) from the target destination rather than true north. This is the part that I got stuck on. The heading value returned from the compass gives you a value that describes where magnetic north is (in degrees east of true north) in relation to where the phone is pointing. So e.g. if the value is -10 you know that magnetic north is 10 degrees to your left. The bearing gives you the angle of your destination in degrees east of true north. So after you've compensated for the declination you can use the formula below to get the desired result:

heading = myBearing - (myBearing + heading); 

You'll then want to convert from degrees east of true north (-180 to +180) into normal degrees (0 to 360):

Math.round(-heading / 360 + 180)

`require': no such file to load -- mkmf (LoadError)

The problem is still is recursive on Ubuntu 13/04/13.10/14.04


sudo apt-get install ruby1.9.1-dev

worked out for me okay. So If you are using Ubuntu 13.04/13.10/14.04 then using this will really come in handy.

This works even if ruby version is 1.9.3. This is because there is no ruby1.9.3-dev available in the Repository...

Java - escape string to prevent SQL injection

The only way to prevent SQL injection is with parameterized SQL. It simply isn't possible to build a filter that's smarter than the people who hack SQL for a living.

So use parameters for all input, updates, and where clauses. Dynamic SQL is simply an open door for hackers, and that includes dynamic SQL in stored procedures. Parameterize, parameterize, parameterize.

Create SQL identity as primary key?

If you're using T-SQL, the only thing wrong with your code is that you used braces {} instead of parentheses ().

PS: Both IDENTITY and PRIMARY KEY imply NOT NULL, so you can omit that if you wish.

How do I automatically update a timestamp in PostgreSQL

Using 'now()' as default value automatically generates time-stamp.

How can I add a vertical scrollbar to my div automatically?

I'm not quite sure what you're attempting to use the div for, but this is an example with some random text.

Mr_Green gave the correct instructions when he said to add overflow-y: auto as that restricts it to vertical scrolling. This is a JSFiddle example:


How to convert a pymongo.cursor.Cursor into a dict?

I suggest create a list and append dictionary into it.

x   = []
cur = db.dbname.find()
for i in cur:

Now x is a list of dictionary, you can manipulate the same in usual python way.

Please initialize the log4j system properly warning

What worked for me is to create a log4j properties file (you can find many examples over the net) and place it in properties folder in your project directory (create this folder if not exicts). The right click on the folder and Build Path->Use as Source Folder.

Hope it helps!

C# LINQ find duplicates in List

there is an answer but i did not understand why is not working;

var anyDuplicate = enumerable.GroupBy(x => x.Key).Any(g => g.Count() > 1);

my solution is like that in this situation;

var duplicates = model.list
                    .GroupBy(s => s.SAME_ID)
                    .Where(g => g.Count() > 1).Count() > 0;
if(duplicates) {

How can I run a php without a web server?

You can use these kind of programs to emulate an apache web server and run PHP on your computer:

How to check a boolean condition in EL?

You can check this way too

<c:if test="${theBooleanVariable ne true}">It's false!</c:if>

How do I run a simple bit of code in a new thread?

BackgroundWorker seems to be best choice for you.

Here is my minimal example. After you click on the button the background worker will begin working in background thread and also report its progress simultaneously. It will also report after the work completes.

using System.ComponentModel;
    private void button1_Click(object sender, EventArgs e)
        BackgroundWorker bw = new BackgroundWorker();

        // this allows our worker to report progress during work
        bw.WorkerReportsProgress = true;

        // what to do in the background thread
        bw.DoWork += new DoWorkEventHandler(
        delegate(object o, DoWorkEventArgs args)
            BackgroundWorker b = o as BackgroundWorker;

            // do some simple processing for 10 seconds
            for (int i = 1; i <= 10; i++)
                // report the progress in percent
                b.ReportProgress(i * 10);


        // what to do when progress changed (update the progress bar for example)
        bw.ProgressChanged += new ProgressChangedEventHandler(
        delegate(object o, ProgressChangedEventArgs args)
            label1.Text = string.Format("{0}% Completed", args.ProgressPercentage);

        // what to do when worker completes its task (notify the user)
        bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(
        delegate(object o, RunWorkerCompletedEventArgs args)
            label1.Text = "Finished!";



  • I put everything in single method using C#'s anonymous method for simplicity but you can always pull them out to different methods.
  • It is safe to update GUI within ProgressChanged or RunWorkerCompleted handlers. However, updating GUI from DoWork will cause InvalidOperationException.

Call one constructor from another

I am improving upon supercat's answer. I guess the following can also be done:

class Sample
    private readonly int _intField;
    public int IntProperty
        get { return _intField; }

    void setupStuff(ref int intField, int newValue)
        //Do some stuff here based upon the necessary initialized variables.
        intField = newValue;

    public Sample(string theIntAsString, bool? doStuff = true)
        //Initialization of some necessary variables.
        int i = int.Parse(theIntAsString);
        // ................
        // .......................

        if (!doStuff.HasValue || doStuff.Value == true)
           setupStuff(ref _intField,i);

    public Sample(int theInt): this(theInt, false) //"false" param to avoid setupStuff() being called two times
        setupStuff(ref _intField, theInt);

Multi column forms with fieldsets

I disagree that .form-group should be within .col-*-n elements. In my experience, all the appropriate padding happens automatically when you use .form-group like .row within a form.

<div class="form-group">
    <div class="col-sm-12">
        <label for="user_login">Username</label>
        <input class="form-control" id="user_login" name="user[login]" required="true" size="30" type="text" />

Check out this demo.

Altering the demo slightly by adding .form-horizontal to the form tag changes some of that padding.

<form action="#" method="post" class="form-horizontal">

Check out this demo.

When in doubt, inspect in Chrome or use Firebug in Firefox to figure out things like padding and margins. Using .row within the form fails in edsioufi's fiddle because .row uses negative left and right margins thereby drawing the horizontal bounds of the divs classed .row beyond the bounds of the containing fieldsets.

Angular 4 checkbox change value

Inside your component class:

checkValue(event: any) {
    state: event

Now in controls you have value A or B

Get parent directory of running script

Try this. Works on both windows or linux server..


Xpath: select div that contains class AND whose specific child element contains text

You could use the xpath :

//div[@class="measure-tab" and .//span[contains(., "someText")]]

Input :

<div class="measure-tab">
  <td> someText</td>
<div class="measure-tab">

Output :

    Element='<div class="measure-tab">

Java Object Null Check for method

public static double calculateInventoryTotal(Book[] arrayBooks) {

    final AtomicReference<BigDecimal> total = new AtomicReference<>(BigDecimal.ZERO);
    Optional.ofNullable(arrayBooks).map(Arrays::asList).ifPresent(books -> books.forEach(book -> total.accumulateAndGet(book.getPrice(), BigDecimal::add)));
    return total.get().doubleValue();


How to create a new database after initally installing oracle database 11g Express Edition?

This link: Creating the Sample Database in Oracle 11g Release 2 is a good example of creating a sample database.

This link: Newbie Guide to Oracle 11g Database Common Problems should help you if you come across some common problems creating your database.

Best of luck!

EDIT: As you are using XE, you should have a DB already created, to connect using SQL*Plus and SQL Developer etc. the info is here: Connecting to Oracle Database Express Edition and Exploring It.


Connecting to Oracle Database XE from SQL Developer SQL Developer is a client program with which you can access Oracle Database XE. With Oracle Database XE 11g Release 2 (11.2), you must use SQL Developer version 3.0. This section assumes that SQL Developer is installed on your system, and shows how to start it and connect to Oracle Database XE. If SQL Developer is not installed on your system, see Oracle Database SQL Developer User's Guide for installation instructions.


For the following procedure: The first time you start SQL Developer on your system, you must provide the full path to java.exe in step 1.

For step 4, you need a user name and password.

For step 6, you need a host name and port.

To connect to Oracle Database XE from SQL Developer:

Start SQL Developer.

For instructions, see Oracle Database SQL Developer User's Guide.

If this is the first time you have started SQL Developer on your system, you are prompted to enter the full path to java.exe (for example, C:\jdk1.5.0\bin\java.exe). Either type the full path after the prompt or browse to it, and then press the key Enter.

The Oracle SQL Developer window opens.

In the navigation frame of the window, click Connections.

The Connections pane appears.

In the Connections pane, click the icon New Connection.

The New/Select Database Connection window opens.

In the New/Select Database Connection window, type the appropriate values in the fields Connection Name, Username, and Password.

For security, the password characters that you type appear as asterisks.

Near the Password field is the check box Save Password. By default, it is deselected. Oracle recommends accepting the default.

In the New/Select Database Connection window, click the tab Oracle.

The Oracle pane appears.

In the Oracle pane:

For Connection Type, accept the default (Basic).

For Role, accept the default.

In the fields Hostname and Port, either accept the defaults or type the appropriate values.

Select the option SID.

In the SID field, type accept the default (xe).

In the New/Select Database Connection window, click the button Test.

The connection is tested. If the connection succeeds, the Status indicator changes from blank to Success.

Description of the illustration success.gif

If the test succeeded, click the button Connect.

The New/Select Database Connection window closes. The Connections pane shows the connection whose name you entered in the Connection Name field in step 4.

You are in the SQL Developer environment.

To exit SQL Developer, select Exit from the File menu.

Elegant solution for line-breaks (PHP)

For linebreaks, PHP as "\n" (see double quote strings) and PHP_EOL.

Here, you are using <br />, which is not a PHP line-break : it's an HTML linebreak.

Here, you can simplify what you posted (with HTML linebreaks) : no need for the strings concatenations : you can put everything in just one string, like this :

$var = "Hi there<br/>Welcome to my website<br/>";

Or, using PHP linebreaks :

$var = "Hi there\nWelcome to my website\n";

Note : you might also want to take a look at the nl2br() function, which inserts <br> before \n.

Codeigniter : calling a method of one controller from other

I agree that the way to do is to redirect to the new controller in usual cases.

I came across a use case where I needed to display the same page to 2 different kind of users (backend user previewing the page of a frontend user) so in my opinion what I needed was genuinely to call the frontend controller from the backend controller.

I solved the problem by making the frontend method static and wrapping it in another method. Hope it helps!

// Frontend
function profile()
   //Access check

   //Get profile id
   $id = get_user_id();

   return self::_profile($id);

static function _profile($id)
   $CI = &get_instance();
   //Prepare page
   //Load view

// Backend
function preview_profile($id)
   $this->load->file('controllers/frontend.php', false);


Detecting a long press with Android

I have created a snippet - inspired by the actual View source - that reliably detects long clicks/presses with a custom delay. But it's in Kotlin:


val handler = Handler()
var boundaries: Rect? = null

var onTap = Runnable {
    handler.postDelayed(onLongPress, LONG_PRESS_DELAY - ViewConfiguration.getTapTimeout().toLong())

var onLongPress = Runnable {

    // Long Press

override fun onTouch(view: View, event: MotionEvent): Boolean {
    when (event.action) {
        MotionEvent.ACTION_DOWN -> {
            boundaries = Rect(view.left,, view.right, view.bottom)
            handler.postDelayed(onTap, ViewConfiguration.getTapTimeout().toLong())
        MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> {
        MotionEvent.ACTION_MOVE -> {
            if (!boundaries!!.contains(view.left + event.x.toInt(), + event.y.toInt())) {
    return true

Make a link in the Android browser start up my app?

I think you'll want to look at the <intent-filter> element of your Mainfest file. Specifically, take a look at the documentation for the <data> sub-element.

Basically, what you'll need to do is define your own scheme. Something along the lines of:

    <data android:scheme="anton" />
    <action android:name="android.intent.action.VIEW" />
    <category android:name="android.intent.category.DEFAULT" />
    <category android:name="android.intent.category.BROWSABLE" /> <--Not positive if this one is needed

Then you should be able to launch your app with links that begin with the anton: URI scheme.

Mysql - How to quit/exit from stored procedure

To handle this situation in a portable way (ie will work on all databases because it doesn’t use MySQL label Kung fu), break the procedure up into logic parts, like this:

CREATE PROCEDURE SP_Reporting(IN tablename VARCHAR(20))
     IF tablename IS NOT NULL THEN
         CALL SP_Reporting_2(tablename);
     END IF;

CREATE PROCEDURE SP_Reporting_2(IN tablename VARCHAR(20))
     #proceed with code

How to dismiss the dialog with click on outside of the dialog?

You can use dialog.setCanceledOnTouchOutside(true); which will close the dialog if you touch outside of the dialog.

Something like,

  Dialog dialog = new Dialog(context)

Or if your Dialog in non-model then,

1 - Set the flag-FLAG_NOT_TOUCH_MODAL for your dialog's window attribute

Window window = this.getWindow();

2 - Add another flag to windows properties,, FLAG_WATCH_OUTSIDE_TOUCH - this one is for dialog to receive touch event outside its visible region.

3 - Override onTouchEvent() of dialog and check for action type. if the action type is 'MotionEvent.ACTION_OUTSIDE' means, user is interacting outside the dialog region. So in this case, you can dimiss your dialog or decide what you wanted to perform. view plainprint?

public boolean onTouchEvent(MotionEvent event)  

       if(event.getAction() == MotionEvent.ACTION_OUTSIDE){  
        System.out.println("TOuch outside the dialog ******************** ");  
       return false;  

For more info look at How to dismiss a custom dialog based on touch points? and How to dismiss your non-modal dialog, when touched outside dialog region

var functionName = function() {} vs function functionName() {}

In computer science terms, we talk about anonymous functions and named functions. I think the most important difference is that an anonymous function is not bound to an name, hence the name anonymous function. In JavaScript it is a first class object dynamically declared at runtime.

For more information on anonymous functions and lambda calculus, Wikipedia is a good start (

SQL - How do I get only the numbers after the decimal?

More generalized approach may be to merge PARSENAME and % operator. (as answered in two of the answers above)

Results as per 1st approach above by SQLMenace

select PARSENAME(0.001,1) 

Result: 001

select PARSENAME(0.0010,1) 

Result: 0010

select PARSENAME(-0.001,1)

Result: 001

select PARSENAME(-1,1)

Result: -1 --> Should not return integer part

select PARSENAME(0,1)

Result: 0

select PARSENAME(1,1)

Result: 1 --> Should not return integer part

select PARSENAME(100.00,1)

Result: 00

Results as per 1st approach above by Pavel Morshenyuk "0." is part of result in this case.

SELECT (100.0001 % 1)

Result: 0.0001

SELECT (100.0010 % 1)

Result: 0.0010

SELECT (0.0001 % 1)

Result: 0.0001

SELECT (0001 % 1)

Result: 0

SELECT (1 % 1)

Result: 0

SELECT (100 % 1)

Result: 0

Combining both:

SELECT PARSENAME((100.0001 % 1),1)

Result: 0001

SELECT PARSENAME((100.0010 % 1),1)

Result: 0010

SELECT PARSENAME((0.0001 % 1),1)

Result: 0001

SELECT PARSENAME((0001 % 1),1)

Result: 0


Result: 0


Result: 0

But still one issue which remains is the zero after the non zero numbers are part of the result (Example: 0.0010 -> 0010). May be one have to apply some other logic to remove that.

Is it possible to insert multiple rows at a time in an SQLite database?

If you use the Sqlite manager firefox plugin, it supports bulk inserts from INSERT SQL statements.

Infact it doesn't support this, but Sqlite Browser does (works on Windows, OS X, Linux)

Getting the size of an array in an object

Arrays have a property .length that returns the number of elements.

var st =

st.itemb.length // 2

Examples of GoF Design Patterns in Java's core libraries

Even though I'm sort of a broken clock with this one, Java XML API uses Factory a lot. I mean just look at this:

Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(source);
String title = XPathFactory.newInstance().newXPath().evaluate("//title", doc);

...and so on and so forth.

Additionally various Buffers (StringBuffer, ByteBuffer, StringBuilder) use Builder.

How to decode HTML entities using jQuery?

To decode HTML Entities with jQuery, just use this function:

function html_entity_decode(txt){
    var randomID = Math.floor((Math.random()*100000)+1);
    $('body').append('<div id="random'+randomID+'"></div>');
    var entity_decoded = $('#random'+randomID).html();
    return entity_decoded;

How to use:


var txtEncoded = "&aacute; &eacute; &iacute; &oacute; &uacute;";


<input id="some-id" type="text" />

How to get array keys in Javascript?

for (var i = 0; i < widthRange.length; ++i) {
  if (widthRange[i] != null) {
    // do something

You can't really get just the keys you've set because that's not how an Array works. Once you set element 46, you also have 0 through 45 set too (though they're null).

You could always have two arrays:

var widthRange = [], widths = [], newVal = function(n) {
  return n;
widthRange[newVal(26)] = { whatever: "hello there" };

for (var i = 0; i < widths.length; ++i) {

edit well it may be that I'm all wet here ...

Recursively find all files newer than a given time

So there's another way (and it is portable to some extent_

(python <<EOF
import fnmatch
import os
import os.path as path
import time

matches = []
def find(dirname=None, newerThan=3*24*3600, olderThan=None):
    for root, dirnames, filenames in os.walk(dirname or '.'):
        for filename in fnmatch.filter(filenames, '*'):
            filepath = os.path.join(root, filename)
            ts_now = time.time()
            newer = ts_now - path.getmtime(filepath) < newerThan
            older = ts_now - path.getmtime(filepath) > newerThan
            if newerThan and newer or olderThan and older: print filepath
    for dirname in dirnames:
        if dirname not in ['.', '..']:
            print 'dir:', dirname
) | xargs -I '{}' echo found file modified within 3 days '{}'

how to display data values on Chart.js

Based on @Ross's answer answer for Chart.js 2.0 and up, I had to include a little tweak to guard against the case when the bar's heights comes too chose to the scale boundary.


The animation attribute of the bar chart's option:

animation: {
            duration: 500,
            easing: "easeOutQuart",
            onComplete: function () {
                var ctx = this.chart.ctx;
                ctx.font = Chart.helpers.fontString(, 'normal',;
                ctx.textAlign = 'center';
                ctx.textBaseline = 'bottom';

       (dataset) {
                    for (var i = 0; i <; i++) {
                        var model = dataset._meta[Object.keys(dataset._meta)[0]].data[i]._model,
                            scale_max = dataset._meta[Object.keys(dataset._meta)[0]].data[i]._yScale.maxHeight;
                        ctx.fillStyle = '#444';
                        var y_pos = model.y - 5;
                        // Make sure data value does not get overflown and hidden
                        // when the bar's value is too close to max value of scale
                        // Note: The y value is reverse, it counts from top down
                        if ((scale_max - model.y) / scale_max >= 0.93)
                            y_pos = model.y + 20; 
                        ctx.fillText([i], model.x, y_pos);

Which port(s) does XMPP use?

According to Wikipedia:

5222 TCP     XMPP client connection (RFC 6120)        Official  
5223 TCP     XMPP client connection over SSL          Unofficial
5269 TCP     XMPP server connection (RFC 6120)        Official
5298 TCP UDP XMPP JEP-0174: Link-Local Messaging /    Official
             XEP-0174: Serverless Messaging
8010 TCP     XMPP File transfers                      Unofficial    

The port numbers are defined in RFC 6120 § 14.7.

File path to resource in our war/WEB-INF folder?

I know this is late, but this is how I normally do it,

ClassLoader classLoader = Thread.currentThread().getContextClassLoader();           
InputStream stream = classLoader.getResourceAsStream("../test/foo.txt");

fitting data with numpy

Unfortunately, np.polynomial.polynomial.polyfit returns the coefficients in the opposite order of that for np.polyfit and np.polyval (or, as you used np.poly1d). To illustrate:

In [40]: np.polynomial.polynomial.polyfit(x, y, 4)
array([  84.29340848, -100.53595376,   44.83281408,   -8.85931101,

In [41]: np.polyfit(x, y, 4)
array([   0.65459882,   -8.859311  ,   44.83281407, -100.53595375,

In general: np.polynomial.polynomial.polyfit returns coefficients [A, B, C] to A + Bx + Cx^2 + ..., while np.polyfit returns: ... + Ax^2 + Bx + C.

So if you want to use this combination of functions, you must reverse the order of coefficients, as in:

ffit = np.polyval(coefs[::-1], x_new)

However, the documentation states clearly to avoid np.polyfit, np.polyval, and np.poly1d, and instead to use only the new(er) package.

You're safest to use only the polynomial package:

import numpy.polynomial.polynomial as poly

coefs = poly.polyfit(x, y, 4)
ffit = poly.polyval(x_new, coefs)
plt.plot(x_new, ffit)

Or, to create the polynomial function:

ffit = poly.Polynomial(coefs)    # instead of np.poly1d
plt.plot(x_new, ffit(x_new))

fit and data plot

How do I correctly clean up a Python object?

The standard way is to use atexit.register:

import atexit
import os

class Package:
    def __init__(self):
        self.files = []

    def cleanup(self):
        print("Running cleanup...")
        for file in self.files:
            print("Unlinking file: {}".format(file))
            # os.unlink(file)

But you should keep in mind that this will persist all created instances of Package until Python is terminated.

Demo using the code above saved as

$ python
>>> from package import *
>>> p = Package()
>>> q = Package()
>>> q.files = ['a', 'b', 'c']
>>> quit()
Running cleanup...
Unlinking file: a
Unlinking file: b
Unlinking file: c
Running cleanup...

How to find the duration of difference between two dates in java?

This is the code:

        String date1 = "07/15/2013";
        String time1 = "11:00:01";
        String date2 = "07/16/2013";
        String time2 = "22:15:10";
        String format = "MM/dd/yyyy HH:mm:ss";
        SimpleDateFormat sdf = new SimpleDateFormat(format);
        Date fromDate = sdf.parse(date1 + " " + time1);
        Date toDate = sdf.parse(date2 + " " + time2);

        long diff = toDate.getTime() - fromDate.getTime();
        String dateFormat="duration: ";
        int diffDays = (int) (diff / (24 * 60 * 60 * 1000));
            dateFormat+=diffDays+" day ";
        diff -= diffDays * (24 * 60 * 60 * 1000);

        int diffhours = (int) (diff / (60 * 60 * 1000));
            dateFormat+=diffhours+" hour ";
        diff -= diffhours * (60 * 60 * 1000);

        int diffmin = (int) (diff / (60 * 1000));
            dateFormat+=diffmin+" min ";
        diff -= diffmin * (60 * 1000);

        int diffsec = (int) (diff / (1000));
            dateFormat+=diffsec+" sec";

and the out is:

duration: 1 day 11 hour 15 min 9 sec

How to Resize image in Swift?


  • Xcode 10.2.1 (10E1001), Swift 5



import UIKit
import CoreGraphics
import Accelerate

extension UIImage {

    public enum ResizeFramework {
        case uikit, coreImage, coreGraphics, imageIO, accelerate

    /// Resize image with ScaleAspectFit mode and given size.
    /// - Parameter dimension: width or length of the image output.
    /// - Parameter resizeFramework: Technique for image resizing: UIKit / CoreImage / CoreGraphics / ImageIO / Accelerate.
    /// - Returns: Resized image.

    func resizeWithScaleAspectFitMode(to dimension: CGFloat, resizeFramework: ResizeFramework = .coreGraphics) -> UIImage? {

        if max(size.width, size.height) <= dimension { return self }

        var newSize: CGSize!
        let aspectRatio = size.width/size.height

        if aspectRatio > 1 {
            // Landscape image
            newSize = CGSize(width: dimension, height: dimension / aspectRatio)
        } else {
            // Portrait image
            newSize = CGSize(width: dimension * aspectRatio, height: dimension)

        return resize(to: newSize, with: resizeFramework)

    /// Resize image from given size.
    /// - Parameter newSize: Size of the image output.
    /// - Parameter resizeFramework: Technique for image resizing: UIKit / CoreImage / CoreGraphics / ImageIO / Accelerate.
    /// - Returns: Resized image.
    public func resize(to newSize: CGSize, with resizeFramework: ResizeFramework = .coreGraphics) -> UIImage? {
        switch resizeFramework {
            case .uikit: return resizeWithUIKit(to: newSize)
            case .coreGraphics: return resizeWithCoreGraphics(to: newSize)
            case .coreImage: return resizeWithCoreImage(to: newSize)
            case .imageIO: return resizeWithImageIO(to: newSize)
            case .accelerate: return resizeWithAccelerate(to: newSize)

    // MARK: - UIKit

    /// Resize image from given size.
    /// - Parameter newSize: Size of the image output.
    /// - Returns: Resized image.
    private func resizeWithUIKit(to newSize: CGSize) -> UIImage? {
        UIGraphicsBeginImageContextWithOptions(newSize, true, 1.0)
        self.draw(in: CGRect(origin: .zero, size: newSize))
        defer { UIGraphicsEndImageContext() }
        return UIGraphicsGetImageFromCurrentImageContext()

    // MARK: - CoreImage

    /// Resize CI image from given size.
    /// - Parameter newSize: Size of the image output.
    /// - Returns: Resized image.
    private func resizeWithCoreImage(to newSize: CGSize) -> UIImage? {
        guard let cgImage = cgImage, let filter = CIFilter(name: "CILanczosScaleTransform") else { return nil }

        let ciImage = CIImage(cgImage: cgImage)
        let scale = (Double)(newSize.width) / (Double)(ciImage.extent.size.width)

        filter.setValue(ciImage, forKey: kCIInputImageKey)
        filter.setValue(NSNumber(value:scale), forKey: kCIInputScaleKey)
        filter.setValue(1.0, forKey: kCIInputAspectRatioKey)
        guard let outputImage = filter.value(forKey: kCIOutputImageKey) as? CIImage else { return nil }
        let context = CIContext(options: [.useSoftwareRenderer: false])
        guard let resultCGImage = context.createCGImage(outputImage, from: outputImage.extent) else { return nil }
        return UIImage(cgImage: resultCGImage)

    // MARK: - CoreGraphics

    /// Resize image from given size.
    /// - Parameter newSize: Size of the image output.
    /// - Returns: Resized image.
    private func resizeWithCoreGraphics(to newSize: CGSize) -> UIImage? {
        guard let cgImage = cgImage, let colorSpace = cgImage.colorSpace else { return nil }

        let width = Int(newSize.width)
        let height = Int(newSize.height)
        let bitsPerComponent = cgImage.bitsPerComponent
        let bytesPerRow = cgImage.bytesPerRow
        let bitmapInfo = cgImage.bitmapInfo

        guard let context = CGContext(data: nil, width: width, height: height,
                                      bitsPerComponent: bitsPerComponent,
                                      bytesPerRow: bytesPerRow, space: colorSpace,
                                      bitmapInfo: bitmapInfo.rawValue) else { return nil }
        context.interpolationQuality = .high
        let rect = CGRect(origin:, size: newSize)
        context.draw(cgImage, in: rect)

        return context.makeImage().flatMap { UIImage(cgImage: $0) }

    // MARK: - ImageIO

    /// Resize image from given size.
    /// - Parameter newSize: Size of the image output.
    /// - Returns: Resized image.
    private func resizeWithImageIO(to newSize: CGSize) -> UIImage? {
        var resultImage = self

        guard let data = jpegData(compressionQuality: 1.0) else { return resultImage }
        let imageCFData = NSData(data: data) as CFData
        let options = [
            kCGImageSourceCreateThumbnailWithTransform: true,
            kCGImageSourceCreateThumbnailFromImageAlways: true,
            kCGImageSourceThumbnailMaxPixelSize: max(newSize.width, newSize.height)
            ] as CFDictionary
        guard   let source = CGImageSourceCreateWithData(imageCFData, nil),
                let imageReference = CGImageSourceCreateThumbnailAtIndex(source, 0, options) else { return resultImage }
        resultImage = UIImage(cgImage: imageReference)

        return resultImage

    // MARK: - Accelerate

    /// Resize image from given size.
    /// - Parameter newSize: Size of the image output.
    /// - Returns: Resized image.
    private func resizeWithAccelerate(to newSize: CGSize) -> UIImage? {
        var resultImage = self

        guard let cgImage = cgImage, let colorSpace = cgImage.colorSpace else { return nil }

        // create a source buffer
        var format = vImage_CGImageFormat(bitsPerComponent: numericCast(cgImage.bitsPerComponent),
                                          bitsPerPixel: numericCast(cgImage.bitsPerPixel),
                                          colorSpace: Unmanaged.passUnretained(colorSpace),
                                          bitmapInfo: cgImage.bitmapInfo,
                                          version: 0,
                                          decode: nil,
                                          renderingIntent: .absoluteColorimetric)
        var sourceBuffer = vImage_Buffer()
        defer {

        var error = vImageBuffer_InitWithCGImage(&sourceBuffer, &format, nil, cgImage, numericCast(kvImageNoFlags))
        guard error == kvImageNoError else { return resultImage }

        // create a destination buffer
        let destWidth = Int(newSize.width)
        let destHeight = Int(newSize.height)
        let bytesPerPixel = cgImage.bitsPerPixel
        let destBytesPerRow = destWidth * bytesPerPixel
        let destData = UnsafeMutablePointer<UInt8>.allocate(capacity: destHeight * destBytesPerRow)
        defer {
        var destBuffer = vImage_Buffer(data: destData, height: vImagePixelCount(destHeight), width: vImagePixelCount(destWidth), rowBytes: destBytesPerRow)

        // scale the image
        error = vImageScale_ARGB8888(&sourceBuffer, &destBuffer, nil, numericCast(kvImageHighQualityResampling))
        guard error == kvImageNoError else { return resultImage }

        // create a CGImage from vImage_Buffer
        let destCGImage = vImageCreateCGImageFromBuffer(&destBuffer, &format, nil, nil, numericCast(kvImageNoFlags), &error)?.takeRetainedValue()
        guard error == kvImageNoError else { return resultImage }

        // create a UIImage
        if let scaledImage = destCGImage.flatMap({ UIImage(cgImage: $0) }) {
            resultImage = scaledImage

        return resultImage


Get image size

import UIKit

extension UIImage {
    func getFileSizeInfo(allowedUnits: ByteCountFormatter.Units = .useMB,
                         countStyle: ByteCountFormatter.CountStyle = .memory,
                         compressionQuality: CGFloat = 1.0) -> String? {
        let formatter = ByteCountFormatter()
        formatter.allowedUnits = allowedUnits
        formatter.countStyle = countStyle
        return getSizeInfo(formatter: formatter, compressionQuality: compressionQuality)

    func getSizeInfo(formatter: ByteCountFormatter, compressionQuality: CGFloat = 1.0) -> String? {
        guard let imageData = jpegData(compressionQuality: compressionQuality) else { return nil }
        return formatter.string(fromByteCount: Int64(imageData.count))

Test function

private func test() {
    guard let img = UIImage(named: "img") else { return }
    printInfo(of: img, title: "original image |")
    let dimension: CGFloat = 2000

    var framework: UIImage.ResizeFramework = .accelerate
    var startTime = Date()
    if let img = img.resizeWithScaleAspectFitMode(to: dimension, resizeFramework: framework) {
        printInfo(of: img, title: "resized image |", with: framework, startedTime: startTime)

    framework = .coreGraphics
    startTime = Date()
    if let img = img.resizeWithScaleAspectFitMode(to: dimension, resizeFramework: framework) {
        printInfo(of: img, title: "resized image |", with: framework, startedTime: startTime)

    framework = .coreImage
    startTime = Date()
    if let img = img.resizeWithScaleAspectFitMode(to: dimension, resizeFramework: framework) {
        printInfo(of: img, title: "resized image |", with: framework, startedTime: startTime)

    framework = .imageIO
    startTime = Date()
    if let img = img.resizeWithScaleAspectFitMode(to: dimension, resizeFramework: framework) {
        printInfo(of: img, title: "resized image |", with: framework, startedTime: startTime)

    framework = .uikit
    startTime = Date()
    if let img = img.resizeWithScaleAspectFitMode(to: dimension, resizeFramework: framework) {
        printInfo(of: img, title: "resized image |", with: framework, startedTime: startTime)

private func printInfo(of image: UIImage, title: String, with resizeFramework: UIImage.ResizeFramework? = nil, startedTime: Date? = nil) {
    var description = "\(title) \(image.size)"
    if let startedTime = startedTime { description += ", execution time: \(Date().timeIntervalSince(startedTime))" }
    if let fileSize = image.getFileSizeInfo(compressionQuality: 0.9) { description += ", size: \(fileSize)" }
    if let resizeFramework = resizeFramework { description += ", framework: \(resizeFramework)" }


original image | (5790.0, 8687.0), size: 17.1 MB
resized image | (1333.0, 2000.0), execution time: 0.8192930221557617, size: 1.1 MB, framework: accelerate
resized image | (1333.0, 2000.0), execution time: 0.44696998596191406, size: 1 MB, framework: coreGraphics
resized image | (1334.0, 2000.0), execution time: 54.172922015190125, size: 1.1 MB, framework: coreImage
resized image | (1333.0, 2000.0), execution time: 1.8765920400619507, size: 1.1 MB, framework: imageIO
resized image | (1334.0, 2000.0), execution time: 0.4638739824295044, size: 1 MB, framework: uikit

Apply function to all elements of collection through LINQ

The idiomatic way to do this with LINQ is to process the collection and return a new collection mapped in the fashion you want. For example, to add a constant to every element, you'd want something like

var newNumbers = oldNumbers.Select(i => i + 8);

Doing this in a functional way instead of mutating the state of your existing collection frequently helps you separate distinct operations in a way that's both easier to read and easier for the compiler to reason about.

If you're in a situation where you actually want to apply an action to every element of a collection (an action with side effects that are unrelated to the actual contents of the collection) that's not really what LINQ is best suited for, although you could fake it with Select (or write your own IEnumerable extension method, as many people have.) It's probably best to stick with a foreach loop in that case.

Docker how to change repository name or rename image?

docker image tag server:latest myname/server:latest


docker image tag d583c3ac45fd myname/server:latest

Tags are just human-readable aliases for the full image name (d583c3ac45fd...).

So you can have as many of them associated with the same image as you like. If you don't like the old name you can remove it after you've retagged it:

docker rmi server

That will just remove the alias/tag. Since d583c3ac45fd has other names, the actual image won't be deleted.

Uncaught ReferenceError: React is not defined

I was facing the same issue. I resolved it by importing React and ReactDOM like as follows:

import React from 'react';
import ReactDOM from 'react-dom';

Display Two <div>s Side-by-Side

Try this : (

.left-div {
    float: left;
    width: 100px;
    /*height: 20px;*/
    margin-right: 8px;
    background-color: linen;
.right-div {

    margin-left: 108px;
    background-color: lime;

<div class="left-div">
<div class="right-div">
    My requirements are <b>[A]</b> Content in the two divs should line up at the top, <b>[B]</b> Long text in right-div should not wrap underneath left-div, and <b>[C]</b> I do not want to specify a width of right-div. I don't want to set the width of right-div because this markup needs to work within different widths.
<div style='clear:both;'>&nbsp;</div>

Hints :

  • Just use float:left in your left-most div only.
  • No real reason to use height, but anyway...
  • Good practice to use <div 'clear:both'>&nbsp;</div> after your last div.

Writing Unicode text to a text file?

That error arises when you try to encode a non-unicode string: it tries to decode it, assuming it's in plain ASCII. There are two possibilities:

  1. You're encoding it to a bytestring, but because you've used, the write method expects a unicode object. So you encode it, and it tries to decode it again. Try: f.write(all_html) instead.
  2. all_html is not, in fact, a unicode object. When you do .encode(...), it first tries to decode it.

Nested ng-repeat

It's better to have a proper JSON format instead of directly using the one converted from XML.

    "number": "2013-W45",
    "days": [
        "dow": "1",
        "templateDay": "Monday",
        "jobs": [
            "name": "Wakeup",
            "jobs": [
                "name": "prepare breakfast",

            "name": "work 9-5",

        "dow": "2",
        "templateDay": "Tuesday",
        "jobs": [
            "name": "Wakeup",
            "jobs": [
                "name": "prepare breakfast",


This will make things much easier and easy to loop through.

Now you can write the loop as -

<div ng-repeat="week in myData">
   <div ng-repeat="day in week.days">
      {{day.dow}} - {{day.templateDay}}
         <li ng-repeat="job in"> 

How can I get the external SD card path for Android 4.0+?

On some devices (for example samsung galaxy sII )internal memory card mabe be in vfat. In this case use refer last code, we obtain path internal memory card (/mnt/sdcad) but no external card. Code refer below solve this problem.

static String getExternalStorage(){
         String exts =  Environment.getExternalStorageDirectory().getPath();
         try {
            FileReader fr = new FileReader(new File("/proc/mounts"));       
            BufferedReader br = new BufferedReader(fr);
            String sdCard=null;
            String line;
            while((line = br.readLine())!=null){
                if(line.contains("secure") || line.contains("asec")) continue;
                String[] pars = line.split("\\s");
                if(pars.length<2) continue;
                if(pars[1].equals(exts)) continue;
                sdCard =pars[1]; 
        return sdCard;  

     } catch (Exception e) {
        // TODO Auto-generated catch block
    return null;

How to export data from Spark SQL to CSV

The answer above with spark-csv is correct but there is an issue - the library creates several files based on the data frame partitioning. And this is not what we usually need. So, you can combine all partitions to one:

    option("header", "true").

and rename the output of the lib (name "part-00000") to a desire filename.

This blog post provides more details:

Apache HttpClient Interim Error: NoHttpResponseException

HttpClient 4.4 suffered from a bug in this area relating to validating possibly stale connections before returning to the requestor. It didn't validate whether a connection was stale, and this then results in an immediate NoHttpResponseException.

This issue was resolved in HttpClient 4.4.1. See this JIRA and the release notes

WebSockets protocol vs HTTP

For the TL;DR, here are 2 cents and a simpler version for your questions:

  1. WebSockets provides these benefits over HTTP:

    • Persistent stateful connection for the duration of the connection
    • Low latency: near-real-time communication between server/client due to no overhead of reestablishing connections for each request as HTTP requires.
    • Full duplex: both server and client can send/receive simultaneously
  2. WebSocket and HTTP protocol have been designed to solve different problems, I.E. WebSocket was designed to improve bi-directional communication whereas HTTP was designed to be stateless, distributed using a request/response model. Other than sharing the ports for legacy reasons (firewall/proxy penetration), there isn't much common ground to combine them into one protocol.

reStructuredText tool support

Salvaging (and extending) the list from an old version of the Wikipedia page:



Although the reference implementation of reStructuredText is written in Python, there are reStructuredText parsers in other languages too.

Python - Docutils

The main distribution of reStructuredText is the Python Docutils package. It contains several conversion tools:

  • rst2html - from reStructuredText to HTML
  • rst2xml - from reStructuredText to XML
  • rst2latex - from reStructuredText to LaTeX
  • rst2odt - from reStructuredText to ODF Text (word processor) document.
  • rst2s5 - from reStructuredText to S5, a Simple Standards-based Slide Show System
  • rst2man - from reStructuredText to Man page

Haskell - Pandoc

Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. It can read Markdown and (subsets of) reStructuredText, HTML, and LaTeX, and it can write Markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, groff man pages, and S5 HTML slide shows.

There is an Pandoc online tool (POT) to try this library. Unfortunately, compared to the reStructuredText online renderer (ROR),

  • POT truncates input rather more shortly. The POT user must render input in chunks that could be rendered whole by the ROR.
  • POT output lacks the helpful error messages displayed by the ROR (and generated by docutils)

Java - JRst

JRst is a Java reStructuredText parser. It can currently output HTML, XHTML, DocBook xdoc and PDF, BUT seems to have serious problems: neither PDF or (X)HTML generation works using the current full download, result pages in (X)HTML are empty and PDF generation fails on IO problems with XSL files (not bundled??). Note that the original JRst has been removed from the website; a fork is found on GitHub.

Scala - Laika

Laika is a new library for transforming markup languages to other output formats. Currently it supports input from Markdown and reStructuredText and produce HTML output. The library is written in Scala but should be also usable from Java.





The Nim compiler features the commands rst2htmland rst2tex which transform reStructuredText files to HTML and TeX files. The standard library provides the following modules (used by the compiler) to handle reStructuredText files programmatically:

  • rst - implements a reStructuredText parser
  • rstast - implements an AST for the reStructuredText parser
  • rstgen - implements a generator of HTML/Latex from reStructuredText

Other 3rd party converters

Most (but not all) of these tools are based on Docutils (see above) and provide conversion to or from formats that might not be supported by the main distribution.

From reStructuredText

  • restview - This pip-installable python package requires docutils, which does the actual rendering. restview's major ease-of-use feature is that, when you save changes to your document(s), it automagically re-renders and re-displays them. restview
    1. starts a small web server
    2. calls docutils to render your document(s) to HTML
    3. calls your device's browser to display the output HTML.
  • rst2pdf - from reStructuredText to PDF
  • rst2odp - from reStructuredText to ODF Presentation
  • rst2beamer - from reStructuredText to LaTeX beamer Presentation class
  • Wikir - from reStructuredText to a Google (and possibly other) Wiki formats
  • rst2qhc - Convert a collection of reStructuredText files into a Qt (toolkit) Help file and (optional) a Qt Help Project file

To reStructuredText

  • xml2rst is an XSLT script to convert Docutils internal XML representation (back) to reStructuredText
  • Pandoc (see above) can also convert from Markdown, HTML and LaTeX to reStructuredText
  • db2rst is a simple and limited DocBook to reStructuredText translator
  • pod2rst - convert .pod files to reStructuredText files


Some projects use reStructuredText as a baseline to build on, or provide extra functionality extending the utility of the reStructuredText tools.


The Sphinx documentation generator translates a set of reStructuredText source files into various output formats, automatically producing cross-references, indices etc.


rest2web is a simple tool that lets you build your website from a single template (or as many as you want), and keep the contents in reStructuredText.


Pygments is a generic syntax highlighter for general use in all kinds of software such as forum systems, Wikis or other applications that need to prettify source code. See Using Pygments in reStructuredText documents.

Free Editors

While any plain text editor is suitable to write reStructuredText documents, some editors have better support than others.


The Emacs support via rst-mode comes as part of the Docutils package under /docutils/tools/editors/emacs/rst.el


The vim-common package for that comes with most GNU/Linux distributions has reStructuredText syntax highlight and indentation support of reStructuredText out of the box:


There is a rst mode for the Jed programmers editor.


gedit, the official text editor of the GNOME desktop environment. There is a gedit reStructuredText plugin.


Geany, a small and lightweight Integrated Development Environment include support for reStructuredText from version 0.12 (October 10, 2007).


Leo, an outlining editor for programmers, supports reStructuredText via rst-plugin or via "@auto-rst" nodes (it's not well-documented, but @auto-rst nodes allow editing rst files directly, parsing the structure into the Leo outline).

It also provides a way to preview the resulting HTML, in a "viewrendered" pane.


The FTE Folding Text Editor - a free (licensed under the GNU GPL) text editor for developers. FTE has a mode for reStructuredText support. It provides color highlighting of basic RSTX elements and special menu that provide easy way to insert most popular RSTX elements to a document.


PyK is a successor of PyEdit and reStInPeace, written in Python with the help of the Qt4 toolkit.


The Eclipse IDE with the ReST Editor plug-in provides support for editing reStructuredText files.


NoTex is a browser based (general purpose) text editor, with integrated project management and syntax highlighting. Plus it enables to write books, reports, articles etc. using rST and convert them to LaTex, PDF or HTML. The PDF files are of high publication quality and are produced via Sphinx with the Texlive LaTex suite.


Notepad++ is a general purpose text editor for Windows. It has syntax highlighting for many languages built-in and support for reStructuredText via a user defined language for reStructuredText.

Visual Studio Code

Visual Studio Code is a general purpose text editor for Windows/macOS/Linux. It has syntax highlighting for many languages built-in and supports reStructuredText via an extension from LeXtudio.

Dedicated reStructuredText Editors

Proprietary editors

Sublime Text

Sublime Text is a completely customizable and extensible source code editor available for Windows, OS X, and Linux. Registration is required for long-term use, but all functions are available in the unregistered version, with occasional reminders to purchase a license. Versions 2 and 3 (currently in beta) support reStructuredText syntax highlighting by default, and several plugins are available through the package manager Package Control to provide snippets and code completion, additional syntax highlighting, conversion to/from RST and other formats, and HTML preview in the browser.

BBEdit / TextWrangler

BBEdit (and its free variant TextWrangler) for Mac can syntax-highlight reStructuredText using this codeless language module.


TextMate, a proprietary general-purpose GUI text editor for Mac OS X, has a bundle for reStructuredText.


Intype is a proprietary text editor for Windows, that support reStructuredText out of the box.

E Text Editor

E is a proprietary Text Editor licensed under the "Open Company License". It supports TextMate's bundles, so it should support reStructuredText the same way TextMate does.


PyCharm (and other IntelliJ platform IDEs?) has ReST/Sphinx support (syntax highlighting, autocomplete and preview).instant preview)


here are some Wiki programs that support the reStructuredText markup as the native markup syntax, or as an add-on:


MediaWiki reStructuredText extension allows for reStructuredText markup in MediaWiki surrounded by <rst> and </rst>.


MoinMoin is an advanced, easy to use and extensible WikiEngine with a large community of users. Said in a few words, it is about collaboration on easily editable web pages.

There is a reStructuredText Parser for MoinMoin.


Trac is an enhanced wiki and issue tracking system for software development projects. There is a reStructuredText Support in Trac.

This Wiki

This Wiki is a Webware for Python Wiki written by Ian Bicking. This wiki uses ReStructuredText for its markup.


rstiki is a minimalist single-file personal wiki using reStructuredText syntax (via docutils) inspired by pwyky. It does not support authorship indication, versioning, hierarchy, chrome/framing/templating or styling. It leverages docutils/reStructuredText as the wiki syntax. As such, it's under 200 lines of code, and in a single file. You put it in a directory and it runs.


Ikiwiki is a wiki compiler. It converts wiki pages into HTML pages suitable for publishing on a website. Ikiwiki stores pages and history in a revision control system such as Subversion or Git. There are many other features, including support for blogging, as well as a large array of plugins. It's reStructuredText plugin, however is somewhat limited and is not recommended as its' main markup language at this time.

Web Services


An Online reStructuredText editor can be used to play with the markup and see the results immediately.

Blogging frameworks


WordPreSt reStructuredText plugin for WordPress. (PHP)


reStructuredText parser plugin for Zine (will become obsolete in version 0.2 when Zine is scheduled to get a native reStructuredText support). Zine is discontinued. (Python)


Pelican is a static blog generator that supports writing articles in ReST. (Python)


Hyde is a static website generator that supports ReST. (Python)


Acrylamid is a static blog generator that supports writing articles in ReST. (Python)


Nikola is a Static Site and Blog Generator that supports ReST. (Python)

ipsum genera

Ipsum genera is a static blog generator written in Nim.


Yozuch is a static blog generator written in Python.


How to Calculate Jump Target Address and Branch Target Address?

For small functions like this you could just count by hand how many hops it is to the target, from the instruction under the branch instruction. If it branches backwards make that hop number negative. if that number doesn't require all 16 bits, then for every number to the left of the most significant of your hop number, make them 1's, if the hop number is positive make them all 0's Since most branches are close to they're targets, this saves you a lot of extra arithmetic for most cases.

  • chris

Where and how is the _ViewStart.cshtml layout file linked?

From ScottGu's blog:

Starting with the ASP.NET MVC 3 Beta release, you can now add a file called _ViewStart.cshtml (or _ViewStart.vbhtml for VB) underneath the \Views folder of your project:

The _ViewStart file can be used to define common view code that you want to execute at the start of each View’s rendering. For example, we could write code within our _ViewStart.cshtml file to programmatically set the Layout property for each View to be the SiteLayout.cshtml file by default:

Because this code executes at the start of each View, we no longer need to explicitly set the Layout in any of our individual view files (except if we wanted to override the default value above).

Important: Because the _ViewStart.cshtml allows us to write code, we can optionally make our Layout selection logic richer than just a basic property set. For example: we could vary the Layout template that we use depending on what type of device is accessing the site – and have a phone or tablet optimized layout for those devices, and a desktop optimized layout for PCs/Laptops. Or if we were building a CMS system or common shared app that is used across multiple customers we could select different layouts to use depending on the customer (or their role) when accessing the site.

This enables a lot of UI flexibility. It also allows you to more easily write view logic once, and avoid repeating it in multiple places.

Also see this.

In a more general sense this ability of MVC framework to "know" about _Viewstart.cshtml is called "Coding by convention".

Convention over configuration (also known as coding by convention) is a software design paradigm which seeks to decrease the number of decisions that developers need to make, gaining simplicity, but not necessarily losing flexibility. The phrase essentially means a developer only needs to specify unconventional aspects of the application. For example, if there's a class Sale in the model, the corresponding table in the database is called “sales” by default. It is only if one deviates from this convention, such as calling the table “products_sold”, that one needs to write code regarding these names.


There's no magic to it. Its just been written into the core codebase of the MVC framework and is therefore something that MVC "knows" about. That why you don't find it in the .config files or elsewhere; it's actually in the MVC code. You can however override to alter or null out these conventions.

CSS vertical alignment text inside li

Define the parent with display: table and the element itself with vertical-align: middle and display: table-cell.

Check if string contains only whitespace

You want to use the isspace() method


Return true if there are only whitespace characters in the string and there is at least one character, false otherwise.

That's defined on every string object. Here it is an usage example for your specific use case:

if aStr and (not aStr.isspace()):
    print aStr

How to integrate sourcetree for gitlab

This worked for me,

Step 1: Click on + New Repository> Clone from URL

Step 2: In Source URL provide URL followed by your user name,


  • GitLab Repo URL :
  • GitLab User Name : zaid.pathan

So final URL should be http://[email protected]/zaid/iosapp.git

Note: zaid.pathan@ added before git.

Step 3: Enjoy cloning :).

Do I need Content-Type: application/octet-stream for file download?


The content-type should be whatever it is known to be, if you know it. application/octet-stream is defined as "arbitrary binary data" in RFC 2046, and there's a definite overlap here of it being appropriate for entities whose sole intended purpose is to be saved to disk, and from that point on be outside of anything "webby". Or to look at it from another direction; the only thing one can safely do with application/octet-stream is to save it to file and hope someone else knows what it's for.

You can combine the use of Content-Disposition with other content-types, such as image/png or even text/html to indicate you want saving rather than display. It used to be the case that some browsers would ignore it in the case of text/html but I think this was some long time ago at this point (and I'm going to bed soon so I'm not going to start testing a whole bunch of browsers right now; maybe later).

RFC 2616 also mentions the possibility of extension tokens, and these days most browsers recognise inline to mean you do want the entity displayed if possible (that is, if it's a type the browser knows how to display, otherwise it's got no choice in the matter). This is of course the default behaviour anyway, but it means that you can include the filename part of the header, which browsers will use (perhaps with some adjustment so file-extensions match local system norms for the content-type in question, perhaps not) as the suggestion if the user tries to save.


Content-Type: application/octet-stream
Content-Disposition: attachment; filename="picture.png"

Means "I don't know what the hell this is. Please save it as a file, preferably named picture.png".

Content-Type: image/png
Content-Disposition: attachment; filename="picture.png"

Means "This is a PNG image. Please save it as a file, preferably named picture.png".

Content-Type: image/png
Content-Disposition: inline; filename="picture.png"

Means "This is a PNG image. Please display it unless you don't know how to display PNG images. Otherwise, or if the user chooses to save it, we recommend the name picture.png for the file you save it as".

Of those browsers that recognise inline some would always use it, while others would use it if the user had selected "save link as" but not if they'd selected "save" while viewing (or at least IE used to be like that, it may have changed some years ago).

How can I calculate the difference between two ArrayLists?

Although this is a very old question in Java 8 you could do something like

 List<String> a1 = Arrays.asList("2009-05-18", "2009-05-19", "2009-05-21");
 List<String> a2 = Arrays.asList("2009-05-18", "2009-05-18", "2009-05-19", "2009-05-19", "2009-05-20", "2009-05-21","2009-05-21", "2009-05-22");

 List<String> result = -> !a1.contains(elem)).collect(Collectors.toList());

IndentationError: unexpected unindent WHY?

It's because you have:

def readTTable(fname):

without a matching except block after the try: block. Every try must have at least one matching except.

See the Errors and Exceptions section of the Python tutorial.

How to parse XML and count instances of a particular node attribute?

There's no need to use a lib specific API if you use python-benedict. Just initialize a new instance from your XML and manage it easily since it is a dict subclass.

Installation is easy: pip install python-benedict

from benedict import benedict as bdict

# data-source can be an url, a filepath or data-string (as in this example)
data_source = """
      <type foobar="1"/>
      <type foobar="2"/>

data = bdict.from_xml(data_source)
t_list = data[''] # yes, keypath supported
for t in t_list:

It supports and normalizes I/O operations with many formats: Base64, CSV, JSON, TOML, XML, YAML and query-string.

It is well tested and open-source on GitHub. Disclosure: I am the author.

Default password of mysql in ubuntu server 16.04

Simply run sudo dpkg-reconfigure mysql-server-5.7

You can find the version you have installed by running dpkg --get-selections | grep mysql-server

Example of a strong and weak entity types

Weak entities are also called dependent entities, since it's existence depends on other entities. Such entities are represented by a double outline rectangle in the E-R diagram.

Strong entities are also called independent entities.

What is the difference between JAX-RS and JAX-WS?

JAX-WS - is Java API for the XML-Based Web Services - a standard way to develop a Web- Services in SOAP notation (Simple Object Access Protocol).

Calling of the Web Services is performed via remote procedure calls. For the exchange of information between the client and the Web Service is used SOAP protocol. Message exchange between the client and the server performed through XML- based SOAP messages.

Clients of the JAX-WS Web- Service need a WSDL file to generate executable code that the clients can use to call Web- Service.

JAX-RS - Java API for RESTful Web Services. RESTful Web Services are represented as resources and can be identified by Uniform Resource Identifiers (URI). Remote procedure call in this case is represented a HTTP- request and the necessary data is passed as parameters of the query. Web Services RESTful - more flexible, can use several different MIME- types. Typically used for XML data exchange or JSON (JavaScript Object Notation) data exchange...

Is it possible to get the index you're sorting over in Underscore.js?

The iterator of _.each is called with 3 parameters (element, index, list). So yes, for _.each you cab get the index.

You can do the same in sortBy

How to move a file?

Although os.rename() and shutil.move() will both rename files, the command that is closest to the Unix mv command is shutil.move(). The difference is that os.rename() doesn't work if the source and destination are on different disks, while shutil.move() doesn't care what disk the files are on.

Java - using System.getProperty("user.dir") to get the home directory

Program to get the current working directory=user.dir

public class CurrentDirectoryExample {

    public static void main(String args[]) {

        String current = System.getProperty("user.dir");
        System.out.println("Current working directory in Java : " + current);

Turn off axes in subplots

import matplotlib.pyplot as plt

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

To turn off axes for all subplots, do either:

[axi.set_axis_off() for axi in ax.ravel()]


map(lambda axi: axi.set_axis_off(), ax.ravel())

How do HashTables deal with collisions?

It will use the equals method to see if the key is present even and especially if there are more than one element in the same bucket.

Why this "Implicit declaration of function 'X'"?

summation and your other functions are defined after they're used in main, and so the compiler has made a guess about it's signature; in other words, an implicit declaration has been assumed.

You should declare the function before it's used and get rid of the warning. In the C99 specification, this is an error.

Either move the function bodies before main, or include method signatures before main, e.g.:

#include <stdio.h>

int summation(int *, int *, int *);

int main()
    // ...

What does this GCC error "... relocation truncated to fit..." mean?

Remember to tackle error messages in order. In my case, the error above this one was "undefined reference", and I visually skipped over it to the more interesting "relocation truncated" error. In fact, my problem was an old library that was causing the "undefined reference" message. Once I fixed that, the "relocation truncated" went away also.

How to find the highest value of a column in a data frame in R?

Similar to colMeans, colSums, etc, you could write a column maximum function, colMax, and a column sort function, colSort.

colMax <- function(data) sapply(data, max, na.rm = TRUE)
colSort <- function(data, ...) sapply(data, sort, ...)

I use ... in the second function in hopes of sparking your intrigue.

Get your data:

dat <- read.table(h=T, text = "Ozone Solar.R Wind Temp Month Day
1     41     190  7.4   67     5   1
2     36     118  8.0   72     5   2
3     12     149 12.6   74     5   3
4     18     313 11.5   62     5   4
5     NA      NA 14.3   56     5   5
6     28      NA 14.9   66     5   6
7     23     299  8.6   65     5   7
8     19      99 13.8   59     5   8
9      8      19 20.1   61     5   9")

Use colMax function on sample data:

#  Ozone Solar.R    Wind    Temp   Month     Day 
#   41.0   313.0    20.1    74.0     5.0     9.0

To do the sorting on a single column,

sort(dat$Solar.R, decreasing = TRUE)
# [1] 313 299 190 149 118  99  19

and over all columns use our colSort function,

colSort(dat, decreasing = TRUE) ## compare with '...' above

PowerShell and the -contains operator

-Contains is actually a collection operator. It is true if the collection contains the object. It is not limited to strings.

-match and -imatch are regular expression string matchers, and set automatic variables to use with captures.

-like, -ilike are SQL-like matchers.

Can't install APK from browser downloads

It shouldn't be HTTP headers if the file has been downloaded successfully and it's the same file that you can open from OI.

A shot in the dark, but could it be that you are not allowing installation from unknown sources, and that OI is somehow bypassing that?

Settings > Applications > Unknown sources...


Answer extracted from comments which worked. Ensure the Content-Type is set to application/

How to create a JPA query with LEFT OUTER JOIN

Normally the ON clause comes from the mapping's join columns, but the JPA 2.1 draft allows for additional conditions in a new ON clause.


Mail not sending with PHPMailer over SSL using SMTP

$mail->Host = "";
$mail->SMTPAuth = true;
$mail->SMTPSecure = "ssl";
$mail->Username = "[email protected]";
$mail->Password = "**********";
$mail->Port = "465";

That is a working configuration.

try to replace what you have

How to declare strings in C

Strings in C are represented as arrays of characters.

char *p = "String";

You are declaring a pointer that points to a string stored some where in your program (modifying this string is undefined behavior) according to the C programming language 2 ed.

char p2[] = "String";

You are declaring an array of char initialized with the string "String" leaving to the compiler the job to count the size of the array.

char p3[5] = "String";

You are declaring an array of size 5 and initializing it with "String". This is an error be cause "String" don't fit in 5 elements.

char p3[7] = "String"; is the correct declaration ('\0' is the terminating character in c strings).

How do I start a process from C#?

You can use this syntax for running any application:


And the same one for a URL. Just write your URL between this ().



How do I convert NSMutableArray to NSArray?

i was search for the answer in swift 3 and this question was showed as first result in search and i get inspired the answer from it so here is the swift 3 code

let array: [String] = nsMutableArrayObject.copy() as! [String]

Plotting time-series with Date labels on x-axis

I like ggplot too.

Here's one example:

df1 = data.frame(
date_id = c('2017-08-01', '2017-08-02', '2017-08-03', '2017-08-04'),          
nation = c('China', 'USA', 'China', 'USA'), 
value = c(4.0, 5.0, 6.0, 5.5))

ggplot(df1, aes(date_id, value, group=nation, colour=nation))+geom_line()+xlab(label='dates')+ylab(label='value')

enter image description here

How to use JavaScript with Selenium WebDriver Java

If you want to read text of any element using javascript executor, you can do something like following code:

WebElement ele = driver.findElement(By.xpath("//div[@class='infaCompositeViewTitle']"));
String assets = (String) js.executeScript("return arguments[0].getElementsByTagName('span')[1].textContent;", ele);

In this example, I have following HTML fragment and I am reading "156".

<div class="infaCompositeViewTitle">
   <span>All Assets</span>

Catching nullpointerexception in Java

As stated already within another answer it is not recommended to catch a NullPointerException. However you definitely could catch it, like the following example shows.

public class Testclass{

    public static void main(String[] args) {
        try {
        } catch (NullPointerException e) {
            System.out.print("Caught the NullPointerException");

    public static void doSomething() {
        String nullString = null;

Although a NPE can be caught you definitely shouldn't do that but fix the initial issue, which is the Check_Circular method.

How to change button text or link text in JavaScript?

Change .text to .textContent to get/set the text content.

Or since you're dealing with a single text node, use in the same manner.

Also, let's make sensible use of a variable, and enjoy some code reduction and eliminate redundant DOM selection by caching the result of getElementById.

function toggleText(button_id) 
   var el = document.getElementById(button_id);
   if ( == "Lock") 
   { = "Unlock";
   { = "Lock";

Or even more compact like this:

function toggleText(button_id)  {
   var text = document.getElementById(button_id).firstChild; = == "Lock" ? "Unlock" : "Lock";

Calling other function in the same controller?


return $this->sendRequest($uri);

Since PHP is not a pure Object-Orieneted language, it interprets sendRequest() as an attempt to invoke a globally defined function (just like nl2br() for example), but since your function is part of a class ('InstagramController'), you need to use $this to point the interpreter in the right direction.

"SetPropertiesRule" warning message when starting Tomcat from Eclipse

I'm finding that Tomcat can't seem to find classes defined in other projects, maybe even in the main project. It's failing on the filter definition which is the first definition in web.xml. If I add the project and its dependencies to the server's launch configuration then I just move on to a new error, all of which seems to point to it not setting up the project properly.

Our setup is quite complex. We have multiple components as projects in Eclipse with separate output projects. We have a separate webapp directory which contains the static HTML and images, as well as our WEB-INF.

Eclipse is "Europa Winter release". Tomcat is 6.0.18. I tried version 2.4 and 2.5 of the "Dynamic Web Module" facet.

Thanks for any help!

  • Richard

for-in statement

edit 2018: This is outdated, js and typescript now have for..of loops.

The book "TypeScript Revealed" says

"You can iterate through the items in an array by using either for or loops as demonstrated here:

// standard for loop
for (var i = 0; i < actors.length; i++)

// loop
for (var actor in actors)


Turns out, the second loop does not pass the actors in the loop. So would say this is plain wrong. Sadly it is as above, loops are untouched by typescript.

map and forEach often help me and are due to typescripts enhancements on function definitions more approachable, lke at the very moment:

this.notes = => new Note(state));

My wish list to TypeScript;

  1. Generic collections
  2. Iterators (IEnumerable, IEnumerator interfaces would be best)

Arduino Nano - "avrdude: ser_open():system can't open device "\\.\COM1": the system cannot find the file specified"

This is how I solved the problem. In Device Manager you will find the Arduino COM port.

Enter image description here

Go to the Advanced properties of the port

Enter image description here

Set the COM port number to COM1.

Enter image description here

Then replug the USB.

Adding items in a Listbox with multiple columns

There is one more way to achieve it:-

Private Sub UserForm_Initialize()
Dim list As Object
Set list = UserForm1.Controls.Add("Forms.ListBox.1", "hello", True)
With list
    .Top = 30
    .Left = 30
    .Width = 200
    .Height = 340
    .ColumnHeads = True
    .ColumnCount = 2
    .ColumnWidths = "100;100"
    .MultiSelect = fmMultiSelectExtended
    .RowSource = "Sheet1!C4:D25"
End With End Sub

Here, I am using the range C4:D25 as source of data for the columns. It will result in both the columns populated with values.

The properties are self explanatory. You can explore other options by drawing ListBox in UserForm and using "Properties Window (F4)" to play with the option values.

'Use of Unresolved Identifier' in Swift

Your NewClass inherits from UIViewController. You declared signedIn in ViewController. If you want NewClass to be able to identify that variable it will have to be declared in a class that your NewClass inherits from.

How is CountDownLatch used in Java Multithreading?

CoundDownLatch enables you to make a thread wait till all other threads are done with their execution.

Pseudo code can be:

// Main thread starts
// Create CountDownLatch for N threads
// Create and start N threads
// Main thread waits on latch
// N threads completes there tasks are returns
// Main thread resume execution

How to tell if a string contains a certain character in JavaScript?

To test for alphanumeric characters only:

if (/^[0-9A-Za-z]+$/.test(yourString))
    //there are only alphanumeric characters
    //it contains other characters

The regex is testing for 1 or more (+) of the set of characters 0-9, A-Z, and a-z, starting with the beginning of input (^) and stopping with the end of input ($).

What's the correct way to communicate between controllers in AngularJS?

The top answer here was a work around from an Angular problem which no longer exists (at least in versions >1.2.16 and "probably earlier") as @zumalifeguard has mentioned. But I'm left reading all these answers without an actual solution.

It seems to me that the answer now should be

  • use $broadcast from the $rootScope
  • listen using $on from the local $scope that needs to know about the event

So to publish

angular.module('test').controller('CtrlPublish', ['$rootScope', '$scope',
function ($rootScope, $scope) {

  $rootScope.$broadcast('topic', 'message');


And subscribe

angular.module('test').controller('ctrlSubscribe', ['$scope',
function ($scope) {

  $scope.$on('topic', function (event, arg) { 
    $scope.receiver = 'got your ' + arg;



If you register the listener on the local $scope, it will be destroyed automatically by $destroy itself when the associated controller is removed.

docker-compose up for only certain containers


Starting with docker-compose 1.28.0 the new service profiles are just made for that! With profiles you can mark services to be only started in specific profiles:

    # ...
    # ...
    profiles: ["cli-only"]
    # ...
docker-compose up # start main services, no npm
docker-compose run --rm npm # run npm service
docker-compose --profile cli-only # start main and all "cli-only" services

original answer

Since docker-compose v1.5 it is possible to pass multiple docker-compose.yml files with the -f flag. This allows you to split your dev tools into a separate docker-compose.yml which you then only include on-demand:

# start and attach to all your essential services
docker-compose up

# execute a defined command in
docker-compose -f run npm update

# if your command depends_on a service you need to include both configs
docker-compose -f docker-compose.yml -f run npm update

For an in-depth discussion on this see docker/compose#1896.

How to show text on image when hovering?

<!DOCTYPE html><html lang='en' class=''>
<head><script src='//'></script><script src='//'></script><script src='//'></script><meta charset='UTF-8'><meta name="robots" content="noindex"><link rel="shortcut icon" type="image/x-icon" href="//" /><link rel="mask-icon" type="" href="//" color="#111" /><link rel="canonical" href="" />
<link href='' rel='stylesheet' type='text/css'>
<link rel='stylesheet prefetch' href=''>
<style class="cp-pen-styles">.product-description {
  transform: translate3d(0, 0, 0);
  transform-style: preserve-3d;
  perspective: 1000;
  backface-visibility: hidden;

body {
  color: #212121;

.container {
  padding-top: 25px;
  padding-bottom: 25px;

img {
  max-width: 100%;

hr {
  border-color: #e5e5e5;
  margin: 15px 0;

.secondary-text {
  color: #b6b6b6;

.list-inline {
  margin: 0;
.list-inline li {
  padding: 0;

.card-wrapper {
  position: relative;
  width: 100%;
  height: 390px;
  border: 1px solid #e5e5e5;
  border-bottom-width: 2px;
  overflow: hidden;
  margin-bottom: 30px;
.card-wrapper:after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
  transition: opacity 0.6s cubic-bezier(0.165, 0.84, 0.44, 1);
.card-wrapper:hover:after {
  opacity: 1;
.card-wrapper:hover .image-holder:before {
  opacity: .75;
.card-wrapper:hover .image-holder:after {
  opacity: 1;
  transform: translate(-50%, -50%);
.card-wrapper:hover .image-holder--original {
  transform: translateY(-15px);
.card-wrapper:hover .product-description {
  height: 205px;
@media (min-width: 768px) {
  .card-wrapper:hover .product-description {
    height: 185px;

.image-holder {
  display: block;
  position: relative;
  width: 100%;
  height: 310px;
  background-color: #ffffff;
  z-index: 1;
@media (min-width: 768px) {
  .image-holder {
    height: 325px;
.image-holder:before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: #4CAF50;
  opacity: 0;
  z-index: 5;
  transition: opacity 0.6s;
.image-holder:after {
  content: '+';
  font-family: 'Raleway', sans-serif;
  font-size: 70px;
  color: #4CAF50;
  text-align: center;
  position: absolute;
  top: 92.5px;
  left: 50%;
  width: 75px;
  height: 75px;
  line-height: 75px;
  background-color: #ffffff;
  opacity: 0;
  border-radius: 50%;
  z-index: 10;
  transform: translate(-50%, 100%);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
  transition: all 0.4s ease-out;
@media (min-width: 768px) {
  .image-holder:after {
    top: 107.5px;
.image-holder .image-holder__link {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 15;
.image-holder .image-holder--original {
  transition: transform 0.8s cubic-bezier(0.165, 0.84, 0.44, 1);

.image-liquid {
  width: 100%;
  height: 325px;
  background-size: cover;
  background-position: center center;

.product-description {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 80px;
  padding: 10px 15px;
  overflow: hidden;
  background-color: #fafafa;
  border-top: 1px solid #e5e5e5;
  transition: height 0.6s cubic-bezier(0.165, 0.84, 0.44, 1);
  z-index: 2;
@media (min-width: 768px) {
  .product-description {
    height: 65px;
.product-description p {
  margin: 0 0 5px;
.product-description .product-description__title {
  font-family: 'Raleway', sans-serif;
  position: relative;
  white-space: nowrap;
  overflow: hidden;
  margin: 0;
  font-size: 18px;
  line-height: 1.25;
.product-description .product-description__title:after {
  content: '';
  width: 60px;
  height: 100%;
  position: absolute;
  top: 0;
  right: 0;
  background: linear-gradient(to right, rgba(255, 255, 255, 0), #fafafa);
.product-description .product-description__title a {
  text-decoration: none;
  color: inherit;
.product-description .product-description__category {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
.product-description .product-description__price {
  color: #4CAF50;
  text-align: left;
  font-weight: bold;
  letter-spacing: 0.06em;
@media (min-width: 768px) {
  .product-description .product-description__price {
    text-align: right;
.product-description .sizes-wrapper {
  margin-bottom: 15px;
.product-description .color-list {
  font-size: 0;
.product-description .color-list__item {
  width: 25px;
  height: 10px;
  position: relative;
  z-index: 1;
  transition: all .2s;
.product-description .color-list__item:hover {
  width: 40px;
.product-description .color-list__item--red {
  background-color: #F44336;
.product-description .color-list__item--blue {
  background-color: #448AFF;
.product-description .color-list__item--green {
  background-color: #CDDC39;
.product-description .color-list__item--orange {
  background-color: #FF9800;
.product-description .color-list__item--purple {
  background-color: #673AB7;
Inspired in this dribbble

<div class="container">
    <div class="row">

        <div class="col-xs-12 col-sm-6 col-md-4">
            <article class="card-wrapper">
                <div class="image-holder">
                    <a href="#" class="image-holder__link"></a>
                    <div class="image-liquid image-holder--original" style="background-image: url('')">

                <div class="product-description">
                    <!-- title -->
                    <h1 class="product-description__title">
                        <a href="#">                        
                            Adidas Originals

                    <!-- category and price -->
                    <div class="row">
                        <div class="col-xs-12 col-sm-8 product-description__category secondary-text">
                            Men's running shirt
                        <div class="col-xs-12 col-sm-4 product-description__price">
                            € 499

                    <!-- divider -->
                    <hr />

                    <!-- sizes -->
                    <div class="sizes-wrapper">
                        <br />
                        <span class="secondary-text text-uppercase">
                            <ul class="list-inline">

                    <!-- colors -->
                    <div class="color-wrapper">
                        <br />
                        <ul class="list-inline color-list">
                            <li class="color-list__item color-list__item--red"></li>
                            <li class="color-list__item color-list__item--blue"></li>
                            <li class="color-list__item color-list__item--green"></li>
                            <li class="color-list__item color-list__item--orange"></li>
                            <li class="color-list__item color-list__item--purple"></li>


        <div class="col-xs-12 col-sm-6 col-md-4">
            <article class="card-wrapper">
                <div class="image-holder">
                    <a href="#" class="image-holder__link"></a>
                    <div class="image-liquid image-holder--original" style="background-image: url('')">

                <div class="product-description">
                    <!-- title -->
                    <h1 class="product-description__title">
                        <a href="#">                        
                            Adidas Originals

                    <!-- category and price -->
                    <div class="row">
                        <div class="col-sm-8 product-description__category secondary-text">
                            Men's running shirt
                        <div class="col-sm-4 product-description__price text-right">
                            € 499

                    <!-- divider -->
                    <hr />

                    <!-- sizes -->
                    <div class="sizes-wrapper">
                        <br />
                        <span class="secondary-text text-uppercase">
                            <ul class="list-inline">

                    <!-- colors -->
                    <div class="color-wrapper">
                        <br />
                        <ul class="list-inline color-list">
                            <li class="color-list__item color-list__item--red"></li>
                            <li class="color-list__item color-list__item--blue"></li>
                            <li class="color-list__item color-list__item--green"></li>
                            <li class="color-list__item color-list__item--orange"></li>
                            <li class="color-list__item color-list__item--purple"></li>


        <div class="col-xs-12 col-sm-6 col-md-4">
            <article class="card-wrapper">
                <div class="image-holder">
                    <a href="#" class="image-holder__link"></a>
                    <div class="image-liquid image-holder--original" style="background-image: url('')">

                <div class="product-description">
                    <!-- title -->
                    <h1 class="product-description__title">
                        <a href="#">                        
                            Adidas Originals

                    <!-- category and price -->
                    <div class="row">
                        <div class="col-sm-8 product-description__category secondary-text">
                            Men's running shirt
                        <div class="col-sm-4 product-description__price text-right">
                            € 499

                    <!-- divider -->
                    <hr />

                    <!-- sizes -->
                    <div class="sizes-wrapper">
                        <br />
                        <span class="secondary-text text-uppercase">
                            <ul class="list-inline">

                    <!-- colors -->
                    <div class="color-wrapper">
                        <br />
                        <ul class="list-inline color-list">
                            <li class="color-list__item color-list__item--red"></li>
                            <li class="color-list__item color-list__item--blue"></li>
                            <li class="color-list__item color-list__item--green"></li>
                            <li class="color-list__item color-list__item--orange"></li>
                            <li class="color-list__item color-list__item--purple"></li>


        <div class="col-xs-12 col-sm-6 col-md-4">
            <article class="card-wrapper">
                <div class="image-holder">
                    <a href="#" class="image-holder__link"></a>
                    <div class="image-liquid image-holder--original" style="background-image: url('')">

                <div class="product-description">
                    <!-- title -->
                    <h1 class="product-description__title">
                        <a href="#">                        
                            Adidas Originals

                    <!-- category and price -->
                    <div class="row">
                        <div class="col-sm-8 product-description__category secondary-text">
                            Men's running shirt
                        <div class="col-sm-4 product-description__price text-right">
                            € 499

                    <!-- divider -->
                    <hr />

                    <!-- sizes -->
                    <div class="sizes-wrapper">
                        <br />
                        <span class="secondary-text text-uppercase">
                            <ul class="list-inline">

                    <!-- colors -->
                    <div class="color-wrapper">
                        <br />
                        <ul class="list-inline color-list">
                            <li class="color-list__item color-list__item--red"></li>
                            <li class="color-list__item color-list__item--blue"></li>
                            <li class="color-list__item color-list__item--green"></li>
                            <li class="color-list__item color-list__item--orange"></li>
                            <li class="color-list__item color-list__item--purple"></li>




The sample is made

Merging two images with PHP

The GD Image Manipulation Library in PHP is probably the best for working with images in PHP. Try one of the imagecopy functions (imagecopy, imagecopymerge, ...). Each of them combine 2 images in different ways. See the php documentation on imagecopy for more information.

How to change line color in EditText

You can change the color of EditText programmatically just using this line of code:edittext.setBackgroundTintList(ColorStateList.valueOf(yourcolor));

android.view.InflateException: Binary XML file line #12: Error inflating class <unknown>

I had the same error on Kitkat which was because i had android:tint on one of the imageViews. It would work fine on Lollipop but crash on Kikkat with Error Inflating class .

Fixed it by using app:tint on the AppCompatImageView which i was dealing with.

VBA Date as integer

Public SUB test()
    Dim mdate As Date
    mdate = now()
    MsgBox (Round(CDbl(mdate), 0))

How do I concatenate strings in Swift?

var language = "Swift" 
var resultStr = "\(language) is a new programming language"

How do I wait until Task is finished in C#?

A clean example that answers the Title

string output = "Error";
Task task = Task.Factory.StartNew(() =>
    output = "Complete";


How to run test methods in specific order in JUnit4?

If you want to run test methods in a specific order in JUnit 5, you can use the below code.

public class MyClassTest { 

    public void test1() {}

    public void test2() {}


Updating records codeigniter

In your_controller write this...

public function update_title() 
    $data = array
        'table_id' => $this->input->post('table_id'),
        'table_title' => $this->input->post('table_title')

    $this->load->model('your_model'); // First load the model
    if($this->your_model->update_title($data)) // call the method from the controller
        // update successful...
        // update not successful...


While in your_model...

public function update_title($data)

This will works fine...

How to play YouTube video in my Android application?

You may use iframe as described in

I am not following the google advises exactly but this is the code I am using and it is working fine

public class CWebVideoView {

    private String url;
    private Context context;
    private WebView webview;
    private static final String HTML_TEMPLATE = "webvideo.html";

    public CWebVideoView(Context context, WebView webview) {
        this.webview = webview;
        this.context = context;

    public void load(String url){
        this.url = url;
        String data = readFromfile(HTML_TEMPLATE, context);
        data = data.replace("%1", url);
        webview.loadData(data, "text/html", "UTF-8");

    public String readFromfile(String fileName, Context context) {
        StringBuilder returnString = new StringBuilder();
        InputStream fIn = null;
        InputStreamReader isr = null;
        BufferedReader input = null;
        try {
            fIn = context.getResources().getAssets().open(fileName, Context.MODE_WORLD_READABLE);
            isr = new InputStreamReader(fIn);
            input = new BufferedReader(isr);
            String line = "";
            while ((line = input.readLine()) != null) {
        } catch (Exception e) {
        } finally {
            try {
                if (isr != null)
                if (fIn != null)
                if (input != null)
            } catch (Exception e2) {
        return returnString.toString();

    public void reload() {
        if (url!=null){

in /assets I have a file called webvideo.html

<!DOCTYPE html>
<html lang="en">
        <meta charset="utf-8">
            iframe   { border: 0; position:fixed; width:100%; height:100%; bgcolor="#000000"; }
            body     { margin: 0; bgcolor="#000000"; }
        <iframe src="%1" frameborder="0" allowfullscreen></iframe>

and now I define a webview inside my main layout

    android:layout_height="match_parent" />

and I use CWebVideoView inside my activity

videoView = (WebView) view.findViewById(;
cWebVideoView = new CWebVideoView(context, videoView);

Passing a callback function to another class

You could change your code in this way:

public delegate void CallbackHandler(string str);

public class ServerRequest
    public void DoRequest(string request, CallbackHandler callback)
        // do stuff....

Center a 'div' in the middle of the screen, even when the page is scrolled up or down?

Correct Method is

    border: solid 1px black;
    position: fixed;
    left: 50%;
    top: 50%;
    background-color: white;
    z-index: 100;
    height: 400px;
    margin-top: -200px;

    width: 600px;
    margin-left: -300px;

What does [object Object] mean? (JavaScript)

Alerts aren't the best for displaying objects. Try console.log? If you still see Object Object in the console, use JSON.parse like this > var obj = JSON.parse(yourObject); console.log(obj)

Check an integer value is Null in c#

There is already a correct answer from Adam, but you have another option to refactor your code:

if (Age.GetValueOrDefault() == 0)
    // it's null or 0

Finding sum of elements in Swift array

@IBOutlet var valueSource: [MultipleIntBoundSource]!

private var allFieldsCount: Int {
    var sum = 0
    valueSource.forEach { sum += $0.count }
    return sum

used this one for nested parameters

Failed to resolve:

dependencies {
    compile ''
    compile ''
    compile ''
    compile ''

apply plugin: ''

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {

        maven { url '' }

    dependencies {
        classpath ''
        classpath ''

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files

allprojects {
    repositories {

Is there an alternative sleep function in C to milliseconds?

Alternatively to usleep(), which is not defined in POSIX 2008 (though it was defined up to POSIX 2004, and it is evidently available on Linux and other platforms with a history of POSIX compliance), the POSIX 2008 standard defines nanosleep():

nanosleep - high resolution sleep

#include <time.h>
int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);

The nanosleep() function shall cause the current thread to be suspended from execution until either the time interval specified by the rqtp argument has elapsed or a signal is delivered to the calling thread, and its action is to invoke a signal-catching function or to terminate the process. The suspension time may be longer than requested because the argument value is rounded up to an integer multiple of the sleep resolution or because of the scheduling of other activity by the system. But, except for the case of being interrupted by a signal, the suspension time shall not be less than the time specified by rqtp, as measured by the system clock CLOCK_REALTIME.

The use of the nanosleep() function has no effect on the action or blockage of any signal.

removing bold styling from part of a header

If you don't want a separate CSS file, you can use inline CSS:

<h1>This text should be bold, <span style="font-weight:normal">but this text should not</span></h1>

However, as Madara's comment suggests, you might want to consider putting the unbolded part in a different header, depending on the use case involved.

Usage of sys.stdout.flush() method

import sys
for x in range(10000):
    print "HAPPY >> %s <<\r" % str(x),

How to top, left justify text in a <td> cell that spans multiple rows

try this

<!DOCTYPE html>_x000D_
table, th, td {_x000D_
    border: 1px solid black;_x000D_
<table style="width:50%;">_x000D_
    <tr style="height:100px">_x000D_
      <td valign="top">January</td>_x000D_
      <td valign="bottom">$100</td>_x000D_
<p><b>Note:</b> The valign attribute is not supported in HTML5. Use CSS instead.</p>_x000D_

use valign="top" for td style

Easy way to use variables of enum types as string in C?

// Define your enumeration like this (in say numbers.h);
ENUM_BEGIN( Numbers )
ENUM_END( Numbers )

// The macros are defined in a more fundamental .h file (say defs.h);
#define ENUM_BEGIN(typ) enum typ {
#define ENUM(nam) nam
#define ENUM_END(typ) };

// Now in one and only one .c file, redefine the ENUM macros and reinclude
//  the numbers.h file to build a string table
#undef ENUM
#undef ENUM_END
#define ENUM_BEGIN(typ) const char * typ ## _name_table [] = {
#define ENUM(nam) #nam
#define ENUM_END(typ) };
#undef NUMBERS_H_INCLUDED   // whatever you need to do to enable reinclusion
#include "numbers.h"

// Now you can do exactly what you want to do, with no retyping, and for any
//  number of enumerated types defined with the ENUM macro family
//  Your code follows;
char num_str[10];
int process_numbers_str(Numbers num) {
  switch(num) {
    case ONE:
    case TWO:
    case THREE:
      strcpy(num_str, Numbers_name_table[num]); // eg TWO -> "TWO"
    } break;
      return 0; //no match
  return 1;

// Sweet no ? After being frustrated by this for years, I finally came up
//  with this solution for my most recent project and plan to reuse the idea
//  forever

How do I tell if .NET 3.5 SP1 is installed?

I came to this page while trying to figure out how to detect the framework versions installed on a server without access to remote desktop or registry, so Danny V's answer worked for me.

string path = System.Environment.SystemDirectory;
path = path.Substring( 0, path.LastIndexOf('\\') );
path = Path.Combine( path, "Microsoft.NET" );
// C:\WINDOWS\Microsoft.NET\

string[] versions = new string[]{
    "Framework\\v3.5\\Microsoft .NET Framework 3.5 SP1",
    "Framework64\\v3.5\\Microsoft .NET Framework 3.5 SP1",

foreach( string version in versions )
    string versionPath = Path.Combine( path, version );

    DirectoryInfo dir = new DirectoryInfo( versionPath );
    if( dir.Exists )
        Response.Output.Write( "{0}<br/>", version );

Check if event exists on element

You may use:


to make sure all click events are unbinded, then attach your event

Android WSDL/SOAP service client

Icesoap, which I found yesterday, looks promising. It worked on a basic test, but it lacks more examples.

Django CharField vs TextField

CharField has max_length of 255 characters while TextField can hold more than 255 characters. Use TextField when you have a large string as input. It is good to know that when the max_length parameter is passed into a TextField it passes the length validation to the TextArea widget.

Multidimensional Lists in C#

It's old but thought I'd add my two cents... Not sure if it will work but try using a KeyValuePair:

 List<KeyValuePair<?, ?>> LinkList = new List<KeyValuePair<?, ?>>();
 LinkList.Add(new KeyValuePair<?, ?>(Object, Object));

You'll end up with something like this:

 LinkList[0] = <Object, Object>
 LinkList[1] = <Object, Object>
 LinkList[2] = <Object, Object>

and so on...

Are parameters in strings.xml possible?

If you need to format your strings using String.format(String, Object...), then you can do so by putting your format arguments in the string resource. For example, with the following resource:

<string name="welcome_messages">Hello, %1$s! You have %2$d new messages.</string>

In this example, the format string has two arguments: %1$s is a string and %2$d is a decimal number. You can format the string with arguments from your application like this:

Resources res = getResources();
String text = String.format(res.getString(R.string.welcome_messages), username, mailCount);

If you wish more look at:

Best way to remove duplicate entries from a data table

In order to distinct all datatable columns, you can easily retrieve the names of the columns in a string array

public static DataTable RemoveDuplicateRows(this DataTable dataTable)
    List<string> columnNames = new List<string>();
    foreach (DataColumn col in dataTable.Columns)
    return dataTable.DefaultView.ToTable(true, columnNames.Select(c => c.ToString()).ToArray());

As you can notice, I thought of using it as an extension to DataTable class

In Tensorflow, get the names of all the Tensors in a graph

Previous answers are good, I'd just like to share a utility function I wrote to select Tensors from a graph:

def get_graph_op(graph, and_conds=None, op='and', or_conds=None):
    """Selects nodes' names in the graph if:
    - The name contains all items in and_conds
    - OR/AND depending on op
    - The name contains any item in or_conds

    Condition starting with a "!" are negated.
    Returns all ops if no optional arguments is given.

        graph (tf.Graph): The graph containing sought tensors
        and_conds (list(str)), optional): Defaults to None.
            "and" conditions
        op (str, optional): Defaults to 'and'. 
            How to link the and_conds and or_conds:
            with an 'and' or an 'or'
        or_conds (list(str), optional): Defaults to None.
            "or conditions"

        list(str): list of relevant tensor names
    assert op in {'and', 'or'}

    if and_conds is None:
        and_conds = ['']
    if or_conds is None:
        or_conds = ['']

    node_names = [ for n in graph.as_graph_def().node]

    ands = {
        n for n in node_names
        if all(
            cond in n if '!' not in cond
            else cond[1:] not in n
            for cond in and_conds

    ors = {
        n for n in node_names
        if any(
            cond in n if '!' not in cond
            else cond[1:] not in n
            for cond in or_conds

    if op == 'and':
        return [
            n for n in node_names
            if n in ands.intersection(ors)
    elif op == 'or':
        return [
            n for n in node_names
            if n in ands.union(ors)

So if you have a graph with ops:


Then running

get_graph_op(tf.get_default_graph(), ['dense', '!kernel'], 'or', ['Assign'])



Succeeded installing but could not start apache 2.4 on my windows 7 system

if you are using windows os and believe that skype is not the suspect, then you might want to check the task manager and check the "Show processes from all users" and make sure that there is NO entry for httpd.exe. Otherwise, end its process. That solves my problem.

How to iterate over the file in python

You should learn about EAFP vs LBYL.

from sys import stdin, stdout
def main(infile=stdin, outfile=stdout):
    if isinstance(infile, basestring):
    if isinstance(outfile, basestring):
    for lineno, line in enumerate(infile, 1):
        line = line.strip()
             print >>outfile, int(line,16)
         except ValueError:
             return "Bad value at line %i: %r" % (lineno, line)

if __name__ == "__main__":
    from sys import argv, exit

Class file for not found

This error occurs only due to the difference in version. Whenever this kinda error occurs try to change the SDK versions, Gradle Build versions, or dependency version. If you are using

targetSdkVersion = 26
compileSdkVersion = 26

then add this version for firebase dependencies.

implementation ''
implementation ''
implementation ''

It works.

RSpec: how to test if a method was called?

To fully comply with RSpec ~> 3.1 syntax and rubocop-rspec's default option for rule RSpec/MessageSpies, here's what you can do with spy:

Message expectations put an example's expectation at the start, before you've invoked the code-under-test. Many developers prefer using an arrange-act-assert (or given-when-then) pattern for structuring tests. Spies are an alternate type of test double that support this pattern by allowing you to expect that a message has been received after the fact, using have_received.

# arrange.
invitation = spy('invitation')

# act.
invitation.deliver("[email protected]")

# assert.
expect(invitation).to have_received(:deliver).with("[email protected]")

If you don't use rubocop-rspec or using non-default option. You may, of course, use RSpec 3 default with expect.

dbl = double("Some Collaborator")
expect(dbl).to receive(:foo).with("[email protected]")

How to create a showdown.js markdown extension

In your last block you have a comma after 'lang', followed immediately with a function. This is not valid json.


It appears that the readme was incorrect. I had to to pass an array with the string 'twitter'.

var converter = new Showdown.converter({extensions: ['twitter']}); converter.makeHtml('whatever @meandave2020'); // output "<p>whatever <a href="">@meandave2020</a></p>" 

I submitted a pull request to update this.

How do I convert a file path to a URL in ASP.NET

The simple solution seems to be to have a temporary location within the website that you can access easily with URL and then you can move files to the physical location when you need to save them.

xlsxwriter: is there a way to open an existing worksheet in my workbook?

After searching a bit about the method to open the existing sheet in xlxs, i discovered

existingWorksheet = wb.get_worksheet_by_name('Your Worksheet name goes here...')

You can now append/write any data to the open worksheet. I hope it helps. Thanks

How do I perform a JAVA callback between classes?

IMO, you should have a look at the Observer Pattern, and this is how most of the listeners work

What is the best way to do a substring in a batch file?

As an additional info to Joey's answer, which isn't described in the help of set /? nor for /?.

%~0 expands to the name of the own batch, exactly as it was typed.
So if you start your batch it will be expanded as

%~0   - mYbAtCh
%~n0  - mybatch
%~nx0 - mybatch.bat

But there is one exception, expanding in a subroutine could fail

echo main- %~0
call :myFunction
exit /b

echo func - %~0
echo func - %~n0
exit /b

This results to

main - myBatch
Func - :myFunction
func - mybatch

In a function %~0 expands always to the name of the function, not of the batch file.
But if you use at least one modifier it will show the filename again!

Redirect to a page/URL after alert button is pressed

Working example in php.
First Alert then Redirect works....

echo "<script>";
echo " alert('Import has successfully Done.');      

Get spinner selected items text?

One line version:

String text = ((Spinner)findViewById(;

UPDATE: You can remove casting if you use SDK 26 (or newer) to compile your project.

String text = findViewById(;

How do I limit the number of rows returned by an Oracle query after ordering?

Pagination queries with ordering are really tricky in Oracle.

Oracle provides a ROWNUM pseudocolumn that returns a number indicating the order in which the database selects the row from a table or set of joined views.

ROWNUM is a pseudocolumn that gets many people into trouble. A ROWNUM value is not permanently assigned to a row (this is a common misunderstanding). It may be confusing when a ROWNUM value is actually assigned. A ROWNUM value is assigned to a row after it passes filter predicates of the query but before query aggregation or sorting.

What is more, a ROWNUM value is incremented only after it is assigned.

This is why the followin query returns no rows:

 select * 
 from (select *
       from some_table
       order by some_column)
 where ROWNUM <= 4 and ROWNUM > 1; 

The first row of the query result does not pass ROWNUM > 1 predicate, so ROWNUM does not increment to 2. For this reason, no ROWNUM value gets greater than 1, consequently, the query returns no rows.

Correctly defined query should look like this:

select *
from (select *, ROWNUM rnum
      from (select *
            from skijump_results
            order by points)
      where ROWNUM <= 4)
where rnum > 1; 

Find out more about pagination queries in my articles on Vertabelo blog:

How do you run a js file using npm scripts?

You should use npm run-script build or npm build <project_folder>. More info here:

Setting Custom ActionBar Title from Fragment

The downside to your approach of casting like so

((MainFragmentActivity) getActivity()).getSupportActionBar().setTitle(

is that your fragment is no longer reusable outside of MainActivityFragment. If you don't plan to use it outside of that activity, then there's no problem. A better approach would be conditionally set the title depending on the activity. So inside your fragment, you would write:

if (getActivity() instanceof ActionBarActivity) {
    ((ActionBarActivity) getActivity()).getSupportActionBar().setTitle("Some Title");

Label points in geom_point

Use geom_text , with aes label. You can play with hjust, vjust to adjust text position.

ggplot(nba, aes(x= MIN, y= PTS, colour="green", label=Name))+
  geom_point() +geom_text(aes(label=Name),hjust=0, vjust=0)

enter image description here

EDIT: Label only values above a certain threshold:

  ggplot(nba, aes(x= MIN, y= PTS, colour="green", label=Name))+
  geom_point() +

chart with conditional labels

Java string replace and the NUL (NULL, ASCII 0) character?

Does replacing a character in a String with a null character even work in Java? I know that '\0' will terminate a c-string.

That depends on how you define what is working. Does it replace all occurrences of the target character with '\0'? Absolutely!

String s = "food".replace('o', '\0');
System.out.println(s.indexOf('\0')); // "1"
System.out.println(s.indexOf('d')); // "3"
System.out.println(s.length()); // "4"
System.out.println(s.hashCode() == 'f'*31*31*31 + 'd'); // "true"

Everything seems to work fine to me! indexOf can find it, it counts as part of the length, and its value for hash code calculation is 0; everything is as specified by the JLS/API.

It DOESN'T work if you expect replacing a character with the null character would somehow remove that character from the string. Of course it doesn't work like that. A null character is still a character!

String s = Character.toString('\0');
System.out.println(s.length()); // "1"
assert s.charAt(0) == 0;

It also DOESN'T work if you expect the null character to terminate a string. It's evident from the snippets above, but it's also clearly specified in JLS (10.9. An Array of Characters is Not a String):

In the Java programming language, unlike C, an array of char is not a String, and neither a String nor an array of char is terminated by '\u0000' (the NUL character).

Would this be the culprit to the funky characters?

Now we're talking about an entirely different thing, i.e. how the string is rendered on screen. Truth is, even "Hello world!" will look funky if you use dingbats font. A unicode string may look funky in one locale but not the other. Even a properly rendered unicode string containing, say, Chinese characters, may still look funky to someone from, say, Greenland.

That said, the null character probably will look funky regardless; usually it's not a character that you want to display. That said, since null character is not the string terminator, Java is more than capable of handling it one way or another.

Now to address what we assume is the intended effect, i.e. remove all period from a string, the simplest solution is to use the replace(CharSequence, CharSequence) overload.

System.out.println("A.E.I.O.U".replace(".", "")); // AEIOU

The replaceAll solution is mentioned here too, but that works with regular expression, which is why you need to escape the dot meta character, and is likely to be slower.

How to install/start Postman native v4.10.3 on Ubuntu 16.04 LTS 64-bit?

Don't forget to add sudo otherwise you will get postman.tar.gz: Permission denied error. And unlink postman if you get error like failed to create symbolic link /usr/bin/postman: File exists. So below is the full code:

sudo wget -O postman.tar.gz
sudo tar -xzf postman.tar.gz -C /opt
sudo rm postman.tar.gz

sudo unlink /usr/bin/postman
sudo ln -s /opt/Postman/Postman /usr/bin/postman

Then just run postman in the terminal.

Return HTML content as a string, given URL. Javascript Function

The only one i have found for Cross-site, is this function:

<script type="text/javascript">
var your_url = '';


<script type="text/javascript" src="jquery.min.js" ></script>
<script type="text/javascript">
// jquery.xdomainajax.js  ------ from padolsey

jQuery.ajax = (function(_ajax){

    var protocol = location.protocol,
        hostname = location.hostname,
        exRegex = RegExp(protocol + '//' + hostname),
        YQL = 'http' + (/^https/.test(protocol)?'s':'') + '://',
        query = 'select * from html where url="{URL}" and xpath="*"';

    function isExternal(url) {
        return !exRegex.test(url) && /:\/\//.test(url);

    return function(o) {

        var url = o.url;

        if ( /get/i.test(o.type) && !/json/i.test(o.dataType) && isExternal(url) ) {

            // Manipulate options so that JSONP-x request is made to YQL

            o.url = YQL;
            o.dataType = 'json';

   = {
                q: query.replace(
                    url + ( ?
                        (/\?/.test(url) ? '&' : '?') + jQuery.param(
                    : '')
                format: 'xml'

            // Since it's a JSONP request
            // complete === success
            if (!o.success && o.complete) {
                o.success = o.complete;
                delete o.complete;

            o.success = (function(_success){
                return function(data) {

                    if (_success) {
                        // Fake XHR callback.
              , {
                            responseText: data.results[0]
                                // YQL screws with <script>s
                                // Get rid of them
                                .replace(/<script[^>]+?\/>|<script(.|\s)*?\/script>/gi, '')
                        }, 'success');



        return _ajax.apply(this, arguments);



    url: your_url,
    type: 'GET',
    success: function(res) {
        var text = res.responseText;
        // then you can manipulate your text as you wish


Check if a given key already exists in a dictionary

The ways in which you can get the results are:

Which is better is dependent on 3 things:

  1. Does the dictionary 'normally has the key' or 'normally does not have the key'.
  2. Do you intend to use conditions like if...else...elseif...else?
  3. How big is dictionary?

Read More:

Use of try/block instead of 'in' or 'if':

except KeyError:
    # Do the operation you wanted to do for "key not present in dict".
    # Do the operation you wanted to do with "key present in dict."

How to use the PI constant in C++

I would recommend just typing in pi to the precision you need. This would add no calculation time to your execution, and it would be portable without using any headers or #defines. Calculating acos or atan is always more expensive than using a precalculated value.

const double PI  =3.141592653589793238463;
const float  PI_F=3.14159265358979f;

Java String new line


This works It will give one space character also along before enter character

Parsing JSON Object in Java

public class JsonParsing {

public static Properties properties = null;

public static JSONObject jsonObject = null;

static {
    properties = new Properties();

public static void main(String[] args) {

    try {

        JSONParser jsonParser = new JSONParser();

        File file = new File("src/main/java/read.json");

        Object object = jsonParser.parse(new FileReader(file));

        jsonObject = (JSONObject) object;


    } catch (Exception ex) {

public static void getArray(Object object2) throws ParseException {

    JSONArray jsonArr = (JSONArray) object2;

    for (int k = 0; k < jsonArr.size(); k++) {

        if (jsonArr.get(k) instanceof JSONObject) {
            parseJson((JSONObject) jsonArr.get(k));
        } else {


public static void parseJson(JSONObject jsonObject) throws ParseException {

    Set<Object> set = jsonObject.keySet();
    Iterator<Object> iterator = set.iterator();
    while (iterator.hasNext()) {
        Object obj =;
        if (jsonObject.get(obj) instanceof JSONArray) {
        } else {
            if (jsonObject.get(obj) instanceof JSONObject) {
                parseJson((JSONObject) jsonObject.get(obj));
            } else {
                System.out.println(obj.toString() + "\t"
                        + jsonObject.get(obj));

How to handle AssertionError in Python and find out which line or statement it occurred on?

Use the traceback module:

import sys
import traceback

    assert True
    assert 7 == 7
    assert 1 == 2
    # many more statements like this
except AssertionError:
    _, _, tb = sys.exc_info()
    traceback.print_tb(tb) # Fixed format
    tb_info = traceback.extract_tb(tb)
    filename, line, func, text = tb_info[-1]

    print('An error occurred on line {} in statement {}'.format(line, text))

How can I introduce multiple conditions in LIKE operator?

Here is an alternative way:

select * from tbl where col like 'ABC%'
select * from tbl where col like 'XYZ%'
select * from tbl where col like 'PQR%';

Here is the test code to verify:

create table tbl (col varchar(255));
insert into tbl (col) values ('ABCDEFG'), ('HIJKLMNO'), ('PQRSTUVW'), ('XYZ');
select * from tbl where col like 'ABC%'
select * from tbl where col like 'XYZ%'
select * from tbl where col like 'PQR%';
| col      |
| XYZ      |
3 rows in set (0.00 sec)

encrypt and decrypt md5

Hashes can not be decrypted check this out.

If you want to encrypt-decrypt, use a two way encryption function of your database like - AES_ENCRYPT (in MySQL).

But I'll suggest CRYPT_BLOWFISH algorithm for storing password. Read this- and

For Blowfish by crypt() function -

crypt('String', '$2a$07$twentytwocharactersalt$');

password_hash will be introduced in PHP 5.5.

$options = [
    'cost' => 7,
    'salt' => 'BCryptRequires22Chrcts',
password_hash("rasmuslerdorf", PASSWORD_BCRYPT, $options);

Once you have stored the password, you can then check if the user has entered correct password by hashing it again and comparing it with the stored value.

How do I interpret precision and scale of a number in a database?

Numeric precision refers to the maximum number of digits that are present in the number.

ie 1234567.89 has a precision of 9

Numeric scale refers to the maximum number of decimal places

ie 123456.789 has a scale of 3

Thus the maximum allowed value for decimal(5,2) is 999.99

Angular.js and HTML5 date input value -- how to get Firefox to show a readable date value in a date input?

If using Angular Material Design, you can use the datepicker component there and this will work in Firefox, IE etc.

Fair warning though - personal experience is that there are problems with this, and seemingly it is being re-worked at present. See here:

Java List.add() UnsupportedOperationException

Not every List implementation supports the add() method.

One common example is the List returned by Arrays.asList(): it is documented not to support any structural modification (i.e. removing or adding elements) (emphasis mine):

Returns a fixed-size list backed by the specified array.

Even if that's not the specific List you're trying to modify, the answer still applies to other List implementations that are either immutable or only allow some selected changes.

You can find out about this by reading the documentation of UnsupportedOperationException and List.add(), which documents this to be an "(optional operation)". The precise meaning of this phrase is explained at the top of the List documentation.

As a workaround you can create a copy of the list to a known-modifiable implementation like ArrayList:

seeAlso = new ArrayList<>(seeAlso);

Display a message in Visual Studio's output window when not debug mode?

The Trace.WriteLine method is a conditionally compiled method. That means that it will only be executed if the TRACE constant is defined when the code is compiled. By default in Visual Studio, TRACE is only defined in DEBUG mode.

Right Click on the Project and Select Properties. Go to the Compile tab. Select Release mode and add TRACE to the defined preprocessor constants. That should fix the issue for you.

Reload parent window from child window

For Atlassian Connect Apps, use AP.navigator.reload();

See details here

Pass multiple parameters to rest API - Spring

Yes its possible to pass JSON object in URL

queryString = "{\"left\":\"" + params.get("left") + "}";
                    Endpoint + "/A/B?query={queryString}",
                    HttpMethod.GET, entity, z.class, queryString); vs onClick

From what I understand, your question is not really about whether to use jQuery or not. It's rather: Is it better to bind events inline in HTML or through event listeners?

Inline binding is deprecated. Moreover this way you can only bind one function to a certain event.

Therefore I recommend using event listeners. This way, you'll be able to bind many functions to a single event and to unbind them later if needed. Consider this pure JavaScript code:

querySelector('#myDiv').addEventListener('click', function () {
    // Some code...

This works in most modern browsers.

However, if you already include jQuery in your project — just use jQuery: .on or .click function.

Mount current directory as a volume in Docker on Windows 10

Other solutions for Git Bash provided by others didn't work for me. Apparently there is currently a bug/limitation in Git for Windows. See this and this.

I finally managed to get it working after finding this GitHub thread (which provides some additional solutions if you're interested, which might work for you, but didn't for me).

I ended up using the following syntax:

MSYS_NO_PATHCONV=1 docker run --rm -it -v $(pwd):/usr/src/project gcc:4.9

Note the MSYS_NO_PATHCONV=1 in front of the docker command and $(pwd) - round brackets, lower-case pwd, no quotes, no backslashes.

Also, I'm using Linux containers on Windows if that matters..

I tested this in the new Windows Terminal, ConEmu and GitBash, and all of them worked for me.

Reversing a String with Recursion in Java

import java.util.*;

public class StringReverser
   static Scanner keyboard = new Scanner(;

   public static String getReverser(String in, int i)
      if (i < 0)
         return "";
         return in.charAt(i) + getReverser(in, i-1);

   public static void main (String[] args)
      int index = 0;

      System.out.println("Enter a String");
      String input = keyboard.nextLine();

      System.out.println(getReverser(input, input.length()-1));

When should I use Lazy<T>?

Just to point onto the example posted by Mathew

public sealed class Singleton
    // Because Singleton's constructor is private, we must explicitly
    // give the Lazy<Singleton> a delegate for creating the Singleton.
    private static readonly Lazy<Singleton> instanceHolder =
        new Lazy<Singleton>(() => new Singleton());

    private Singleton()

    public static Singleton Instance
        get { return instanceHolder.Value; }

before the Lazy was born we would have done it this way:

private static object lockingObject = new object();
public static LazySample InstanceCreation()
    if(lazilyInitObject == null)
         lock (lockingObject)
              if(lazilyInitObject == null)
                   lazilyInitObject = new LazySample ();
    return lazilyInitObject ;

How to get just the date part of getdate()?

try this:

select convert (date ,getdate())


select CAST (getdate() as DATE)


select convert(varchar(10), getdate(),121)

Remove HTML Tags in Javascript with Regex

you can use a powerful library for management String which is undrescore.string.js

_('a <a href="#">link</a>').stripTags()

=> 'a link'

_('a <a href="#">link</a><script>alert("hello world!")</script>').stripTags()

=> 'a linkalert("hello world!")'

Don't forget to import this lib as following :

        <script src="underscore.js" type="text/javascript"></script>
        <script src="underscore.string.js" type="text/javascript"></script>
        <script type="text/javascript"> _.mixin(_.str.exports())</script>

Unit Tests not discovered in Visual Studio 2017


The top answers above did not work for me (restarting, updating to version 1.1.18 ... I was already updated, deleting the temp files, clearning NuGet cache etc).

What I discovered is that I had differing references to MSTest.TestAdapter and MSTest.Framework in different test projects (my solution has two). One was pointed to 1.1.18 like...


<package id="MSTest.TestAdapter" version="1.1.18" targetFramework="net461" />
<package id="MSTest.TestFramework" version="1.1.18" targetFramework="net461" />

... but another has the references to 1.1.11. Some of the answers above lead to this discovery when two versions of the libraries showed up in my temp directory (%TEMP%\VisualStudioTestExplorerExtensions\) after restarting Visual Studio.


Simply updating my packages.config to the 1.1.18 version is what restored my unit tests functionality in VS. It appears that there are some bugs that do not allow side-by-side references of the MSTest libraries. Hope this helps you.

More info:

  • Visual Studio 2017 Ent: 15.5.6 (I had updated from 15.0.1 with hopes to fix this issue, but I had it in both)

JavaScript window resize event

The already mentioned solutions above will work if all you want to do is resize the window and window only. However, if you want to have the resize propagated to child elements, you will need to propagate the event yourself. Here's some example code to do it:

window.addEventListener("resize", function () {
  var recResizeElement = function (root) {, function (el) {

      var resizeEvent = document.createEvent("HTMLEvents");
      resizeEvent.initEvent("resize", false, true);
      var propagate = el.dispatchEvent(resizeEvent);

      if (propagate)

Note that a child element can call


on the event object that is passed in as the first Arg of the resize event. For example:

var child1 = document.getElementById("child1");
child1.addEventListener("resize", function (event) {

How to display with n decimal places in Matlab

You can convert a number to a string with n decimal places using the SPRINTF command:

>> x = 1.23;
>> sprintf('%0.6f', x)

ans =


>> x = 1.23456789;
>> sprintf('%0.6f', x)

ans =


Do standard windows .ini files allow comments?

Windows INI API support for:

  • Line comments: yes, using semi-colon ;
  • Trailing comments: No

The authoritative source is the Windows API function that reads values out of INI files


Retrieves a string from the specified section in an initialization file.

The reason "full line comments" work is because the requested value does not exist. For example, when parsing the following ini file contents:

pepsi=diet   ;gag

Reading the values:

  • UseLiveData: 1
  • coke: not present
  • ;coke: not present
  • pepsi: diet ;gag
  • stackoverflow: not present
  • #stackoverflow: splotchy

Update: I used to think that the number sign (#) was a pseudo line-comment character. The reason using leading # works to hide stackoverflow is because the name stackoverflow no longer exists. And it turns out that semi-colon (;) is a line-comment.

But there is no support for trailing comments.

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

After logging in, on the home page of the Server Console you should see 3 sections:

  • Information and Resources
  • Domain Configurations
  • Services Configurations

Under Services Configurations there is subsection Other Services. Click the JTA Configuration link under Other Services. The transaction timeout should be the top setting on the page displayed, labelled Timeout Seconds.

Weblogic Console screenshot

How do I override nested NPM dependency versions?

For those using yarn.

I tried using npm shrinkwrap until I discovered the yarn cli ignored my npm-shrinkwrap.json file.

Yarn has for this. Neat.

Check out this answer too:

Spring mvc @PathVariable

Let us assume you hit a url as . Now you have to retrieve value 111 (which is dynamic) to your controller method .At time you ll be using @PathVariable as follows :

@RequestMapping(value = " /test/{testvalue}", method=RequestMethod.GET)
public void test(@PathVariable String testvalue){
//you can use test value here

SO the variable value is retrieved from the url

Why does Git treat this text file as a binary file?

If git check-attr --all -- src/my_file.txt indicates that your file is flagged as binary, and you haven't set it as binary in .gitattributes, check for it in /.git/info/attributes.