Programs & Examples On #Xmlconvert

Where's the DateTime 'Z' format specifier?

Round tripping dates through strings has always been a pain...but the docs to indicate that the 'o' specifier is the one to use for round tripping which captures the UTC state. When parsed the result will usually have Kind == Utc if the original was UTC. I've found that the best thing to do is always normalize dates to either UTC or local prior to serializing then instruct the parser on which normalization you've chosen.

DateTime now = DateTime.Now;
DateTime utcNow = now.ToUniversalTime();

string nowStr = now.ToString( "o" );
string utcNowStr = utcNow.ToString( "o" );

now = DateTime.Parse( nowStr );
utcNow = DateTime.Parse( nowStr, null, DateTimeStyles.AdjustToUniversal );

Debug.Assert( now == utcNow );

pandas: to_numeric for multiple columns

df.loc[:,'col':] = df.loc[:,'col':].apply(pd.to_numeric, errors = 'coerce')

FontAwesome icons not showing. Why?

I solved this problem by putting the Fonts directory at the same level as my CSS files.

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

Callbacks in C are usually implemented using function pointers and an associated data pointer. You pass your function on_event() and data pointers to a framework function watch_events() (for example). When an event happens, your function is called with your data and some event-specific data.

Callbacks are also used in GUI programming. The GTK+ tutorial has a nice section on the theory of signals and callbacks.

Vagrant error : Failed to mount folders in Linux guest

The plugin vagrant-vbguest GitHub RubyGems solved my problem:

$ vagrant plugin install vagrant-vbguest


$ vagrant reload
==> default: Attempting graceful shutdown of VM...
==> default: Machine booted and ready!
GuestAdditions 4.3.12 running --- OK.
==> default: Checking for guest additions in VM...
==> default: Configuring and enabling network interfaces...
==> default: Exporting NFS shared folders...
==> default: Preparing to edit /etc/exports. Administrator privileges will be required...
==> default: Mounting NFS shared folders...
==> default: VM already provisioned. Run `vagrant provision` or use `--provision` to force it

Just make sure you are running the latest version of VirtualBox

Functions that return a function

Returning b is returning a function object. In Javascript, functions are just objects, like any other object. If you find that not helpful, just replace the word "object" with "thing". You can return any object from a function. You can return a true/false value. An integer (1,2,3,4...). You can return a string. You can return a complex object with multiple properties. And you can return a function. a function is just a thing.

In your case, returning b returns the thing, the thing is a callable function. Returning b() returns the value returned by the callable function.

Consider this code:

function b() {
   return 42;

Using the above definition, return b(); returns the value 42. On the other hand return b; returns a function, that itself returns the value of 42. They are two different things.

What is the main difference between Collection and Collections in Java?

As per Java Doc Collection is:

The root interface in the collection hierarchy. A collection represents a group of objects, known as its elements. Some collections allow duplicate elements and others do not. Some are ordered and others unordered. The JDK does not provide any direct implementations of this interface: it provides implementations of more specific subinterfaces like Set and List. This interface is typically used to pass collections around and manipulate them where maximum generality is desired.

Where as Collections is:

This class consists exclusively of static methods that operate on or return collections. It contains polymorphic algorithms that operate on collections, "wrappers", which return a new collection backed by a specified collection, and a few other odds and ends.

Converting String to Double in Android

    cost=(TextView )findViewById(;

            btn.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) { cst =  Double.valueOf(kw.getText().toString());
            cst = cst*0.551;

Get child node index

I hypothesize that given an element where all of its children are ordered on the document sequentially, the fastest way should be to do a binary search, comparing the document positions of the elements. However, as introduced in the conclusion the hypothesis is rejected. The more elements you have, the greater the potential for performance. For example, if you had 256 elements, then (optimally) you would only need to check just 16 of them! For 65536, only 256! The performance grows to the power of 2! See more numbers/statistics. Visit Wikipedia

   'use strict';
    Object.defineProperty(constructor.prototype, 'parentIndex', {
      get: function() {
        var searchParent = this.parentElement;
        if (!searchParent) return -1;
        var searchArray = searchParent.children,
            thisOffset = this.offsetTop,
            stop = searchArray.length,
            p = 0,
            delta = 0;
        while (searchArray[p] !== this) {
            if (searchArray[p] > this)
                stop = p + 1, p -= delta;
            delta = (stop - p) >>> 1;
            p += delta;
        return p;
})(window.Element || Node);

Then, the way that you use it is by getting the 'parentIndex' property of any element. For example, check out the following demo.

   'use strict';
    Object.defineProperty(constructor.prototype, 'parentIndex', {
      get: function() {
        var searchParent = this.parentNode;
        if (searchParent === null) return -1;
        var childElements = searchParent.children,
            lo = -1, mi, hi = childElements.length;
        while (1 + lo !== hi) {
            mi = (hi + lo) >> 1;
            if (!(this.compareDocumentPosition(childElements[mi]) & 0x2)) {
                hi = mi;
            lo = mi;
        return childElements[hi] === this ? hi : -1;
})(window.Element || Node);

output.textContent = document.body.parentIndex;
output2.textContent = document.documentElement.parentIndex;
Body parentIndex is <b id="output"></b><br />
documentElements parentIndex is <b id="output2"></b>


  • This implementation of the solution will not work in IE8 and below.

Binary VS Linear Search On 200,000 elements (might crash some mobile browsers, BEWARE!):

  • In this test, we will see how long it takes for a linear search to find the middle element VS a binary search. Why the middle element? Because it is at the average location of all the other locations, so it best represents all of the possible locations.

Binary Search

   'use strict';
    Object.defineProperty(constructor.prototype, 'parentIndexBinarySearch', {
      get: function() {
        var searchParent = this.parentNode;
        if (searchParent === null) return -1;
        var childElements = searchParent.children,
            lo = -1, mi, hi = childElements.length;
        while (1 + lo !== hi) {
            mi = (hi + lo) >> 1;
            if (!(this.compareDocumentPosition(childElements[mi]) & 0x2)) {
                hi = mi;
            lo = mi;
        return childElements[hi] === this ? hi : -1;
})(window.Element || Node);
test.innerHTML = '<div> </div> '.repeat(200e+3);
// give it some time to think:
  var child=test.children.item(99.9e+3);
  var, end=Math.round(Math.random());
  for (var i=200 + end; i-- !== end; )
    console.assert( test.children.item(
        Math.round(99.9e+3+i+Math.random())).parentIndexBinarySearch );
    output.textContent = 'It took the binary search ' + ((end-start)*10).toFixed(2) + 'ms to find the 999 thousandth to 101 thousandth children in an element with 200 thousand children.';
    test = null; // free up reference
  }, 125);
}, 125);
<output id=output> </output><br />
<div id=test style=visibility:hidden;white-space:pre></div>

Backwards (`lastIndexOf`) Linear Search

(function(t){"use strict";var e=Array.prototype.lastIndexOf;Object.defineProperty(t.prototype,"parentIndexLinearSearch",{get:function(){return,this)}})})(window.Element||Node);
test.innerHTML = '<div> </div> '.repeat(200e+3);
// give it some time to think:
  var child=test.children.item(99e+3);
  var, end=Math.round(Math.random());
  for (var i=2000 + end; i-- !== end; )
    console.assert( test.children.item(
        Math.round(99e+3+i+Math.random())).parentIndexLinearSearch );
    output.textContent = 'It took the backwards linear search ' + (end-start).toFixed(2) + 'ms to find the 999 thousandth to 101 thousandth children in an element with 200 thousand children.';
    test = null; // free up reference
  }, 125);
<output id=output> </output><br />
<div id=test style=visibility:hidden;white-space:pre></div>

Forwards (`indexOf`) Linear Search

(function(t){"use strict";var e=Array.prototype.indexOf;Object.defineProperty(t.prototype,"parentIndexLinearSearch",{get:function(){return,this)}})})(window.Element||Node);
test.innerHTML = '<div> </div> '.repeat(200e+3);
// give it some time to think:
  var child=test.children.item(99e+3);
  var, end=Math.round(Math.random());
  for (var i=2000 + end; i-- !== end; )
    console.assert( test.children.item(
        Math.round(99e+3+i+Math.random())).parentIndexLinearSearch );
    output.textContent = 'It took the forwards linear search ' + (end-start).toFixed(2) + 'ms to find the 999 thousandth to 101 thousandth children in an element with 200 thousand children.';
    test = null; // free up reference
  }, 125);
<output id=output> </output><br />
<div id=test style=visibility:hidden;white-space:pre></div>

PreviousElementSibling Counter Search

Counts the number of PreviousElementSiblings to get the parentIndex.

   'use strict';
    Object.defineProperty(constructor.prototype, 'parentIndexSiblingSearch', {
      get: function() {
        var i = 0, cur = this;
        do {
            cur = cur.previousElementSibling;
        } while (cur !== null)
        return i; //Returns 3
})(window.Element || Node);
test.innerHTML = '<div> </div> '.repeat(200e+3);
// give it some time to think:
  var child=test.children.item(99.95e+3);
  var, end=Math.round(Math.random());
  for (var i=100 + end; i-- !== end; )
    console.assert( test.children.item(
        Math.round(99.95e+3+i+Math.random())).parentIndexSiblingSearch );
    output.textContent = 'It took the PreviousElementSibling search ' + ((end-start)*20).toFixed(2) + 'ms to find the 999 thousandth to 101 thousandth children in an element with 200 thousand children.';
    test = null; // free up reference
  }, 125);
<output id=output> </output><br />
<div id=test style=visibility:hidden;white-space:pre></div>

No Search

For benchmarking what the result of the test would be if the browser optimized out the searching.

test.innerHTML = '<div> </div> '.repeat(200e+3);
// give it some time to think:
  var, end=Math.round(Math.random());
  for (var i=2000 + end; i-- !== end; )
    console.assert( true );
    output.textContent = 'It took the no search ' + (end-start).toFixed(2) + 'ms to find the 999 thousandth to 101 thousandth children in an element with 200 thousand children.';
    test = null; // free up reference
  }, 125);
<output id=output> </output><br />
<div id=test style=visibility:hidden></div>

The Conculsion

However, after viewing the results in Chrome, the results are the opposite of what was expected. The dumber forwards linear search was a surprising 187 ms, 3850%, faster than the binary search. Evidently, Chrome somehow magically outsmarted the console.assert and optimized it away, or (more optimistically) Chrome internally uses numerical indexing system for the DOM, and this internal indexing system is exposed through the optimizations applied to Array.prototype.indexOf when used on a HTMLCollection object.

How do you add an SDK to Android Studio?

And For linux(ubuntu)


Parse JSON response using jQuery

Original question was to parse a list of topics, however starting with the original example to have a function return a single value may also useful. To that end, here is an example of (one way) to do that:

<script type='text/javascript'>
    function getSingleValueUsingJQuery() {
      var value = "";
      var url = "rest/endpointName/" + document.getElementById('someJSPFieldName').value;
        type: 'GET',
        url: url,
        async: false,
        contentType: "application/json",
        dataType: 'json',
        success: function(json) {
          console.log(json.value);   // needs to match the payload (i.e. json must have {value: "foo"}
          value = json.value;
        error: function(e) {
          console.log("jQuery error message = "+e.message);
      return value;

Update ViewPager dynamically?

For some reason none of the answers worked for me so I had to override the restoreState method without calling super in my fragmentStatePagerAdapter. Code:

private class MyAdapter extends FragmentStatePagerAdapter {

    // [Rest of implementation]

    public void restoreState(Parcelable state, ClassLoader loader) {}


How to copy data from another workbook (excel)?

Two years later (Found this on Google, so for anyone else)... As has been mentioned above, you don't need to select anything. These three lines:

Workbooks(File).Worksheets(SheetData).Range(Selection, Selection.End(xlToRight)).Select
Workbooks(File).Worksheets(SheetData).Selection.Copy ActiveWorkbook.Sheets(sheetName).Cells(1, 1)

Can be replaced with

Workbooks(File).Worksheets(SheetData).Range(Workbooks(File).Worksheets(SheetData). _
Range("A1"), Workbooks(File).Worksheets(SheetData).Range("A1").End(xlToRight)).Copy _
Destination:=ActiveWorkbook.Sheets(sheetName).Cells(1, 1)

This should get around the select error.

ld: framework not found Pods

I cleared this error by deleting the red .framework files that were located in a folder Frameworks in the project navigator. I think this also automatically deleted corresponding red entries in the Linked Frameworks and Libraries section of the General settings.

I have been cleaning / reinstalling pods in order to fix another issue. Perhaps these red framework files and entries were just leftover from a previous pod install?

how to configure lombok in eclipse luna

While installing lombok in ubuntu machine with java -jar lombok.jar you may find following error:

java.awt.AWTError: Assistive Technology not found: org.GNOME.Accessibility.AtkWrapper

You can overcome this by simply doing following steps:

Step 1: This can be done by editing the file of JDK:

sudo gedit /etc/java-8-openjdk/

Step 2: Comment (#) the following line:


Getting the last argument passed to a shell script

This is part of my copy function:

eval echo $(echo '$'"$#")

To use in scripts, do this:

a=$(eval echo $(echo '$'"$#"))

Explanation (most nested first):

  1. $(echo '$'"$#") returns $[nr] where [nr] is the number of parameters. E.g. the string $123 (unexpanded).
  2. echo $123 returns the value of 123rd parameter, when evaluated.
  3. eval just expands $123 to the value of the parameter, e.g. last_arg. This is interpreted as a string and returned.

Works with Bash as of mid 2015.

OSError: [WinError 193] %1 is not a valid Win32 application

For me issue got resolved after following steps :

  1. Installing python 32 bit version on windows.
  2. Add newly installed python and it's script folder(where pip resides in environment variable)

Issue comes when any application you want to run needs python 32 bit variants and you have 64 bit variant

Note : Once you install python 32 bit variant,dont forget to install all required packages using pip of this new python 32 bit variant

How do I perform the SQL Join equivalent in MongoDB?

As others have pointed out you are trying to create a relational database from none relational database which you really don't want to do but anyways, if you have a case that you have to do this here is a solution you can use. We first do a foreach find on collection A( or in your case users) and then we get each item as an object then we use object property (in your case uid) to lookup in our second collection (in your case comments) if we can find it then we have a match and we can print or do something with it. Hope this helps you and good luck :)

function (object) {
    var commonInBoth=db.comments.findOne({ "uid": object.uid} );
    if (commonInBoth != null) {
        printjson(commonInBoth) ;
        printjson(object) ;
    }else {
        // did not match so we don't care in this case

How to form a correct MySQL connection string?

Here is an example:

MySqlConnection con = new MySqlConnection(

MySqlCommand cmd = new MySqlCommand(
    " INSERT Into Test (lat, long) VALUES ('"+OSGconv.deciLat+"','"+
    OSGconv.deciLon+"')", con);


Select rows of a matrix that meet a condition

m <- matrix(1:20, ncol = 4) 
colnames(m) <- letters[1:4]

The following command will select the first row of the matrix above.

subset(m, m[,4] == 16)

And this will select the last three.

subset(m, m[,4] > 17)

The result will be a matrix in both cases. If you want to use column names to select columns then you would be best off converting it to a dataframe with

mf <- data.frame(m)

Then you can select with

mf[ mf$a == 16, ]

Or, you could use the subset command.

I want to convert std::string into a const wchar_t *

If you have a std::wstring object, you can call c_str() on it to get a wchar_t*:

std::wstring name( L"Steve Nash" );
const wchar_t* szName = name.c_str();

Since you are operating on a narrow string, however, you would first need to widen it. There are various options here; one is to use Windows' built-in MultiByteToWideChar routine. That will give you an LPWSTR, which is equivalent to wchar_t*.

Eclipse reports rendering library more recent than ADT plug-in

Am i change API version 17, 19, 21, & 23 in xml layoutside


Updated Android Development Tools 23.0.7 but still can't render layout proper so am i updated Android DDMS 23.0.7 it's works perfect..!!!

Is it better in C++ to pass by value or pass by constant reference?

This is what i normally work by when designing the interface of a non-template function:

  1. Pass by value if the function does not want to modify the parameter and the value is cheap to copy (int, double, float, char, bool, etc... Notice that std::string, std::vector, and the rest of the containers in the standard library are NOT)

  2. Pass by const pointer if the value is expensive to copy and the function does not want to modify the value pointed to and NULL is a value that the function handles.

  3. Pass by non-const pointer if the value is expensive to copy and the function wants to modify the value pointed to and NULL is a value that the function handles.

  4. Pass by const reference when the value is expensive to copy and the function does not want to modify the value referred to and NULL would not be a valid value if a pointer was used instead.

  5. Pass by non-const reference when the value is expensive to copy and the function wants to modify the value referred to and NULL would not be a valid value if a pointer was used instead.

how do you insert null values into sql server

If you're using SSMS (or old school Enterprise Manager) to edit the table directly, press CTRL+0 to add a null.

Why can't I call a public method in another class?

You're trying to call an instance method on the class. To call an instance method on a class you must create an instance on which to call the method. If you want to call the method on non-instances add the static keyword. For example

class Example {
  public static string NonInstanceMethod() {
    return "static";
  public string InstanceMethod() { 
    return "non-static";

static void SomeMethod() {
  Console.WriteLine(Example.InstanceMethod());  // Does not compile
  Example v1 = new Example();

Set focus to field in dynamically loaded DIV

As Omu pointed out, you must set the focus in a document ready function. jQuery provides it for you. And do select on an id. For example, if you have a login page:

$(function() { $("#login-user-name").focus(); }); // jQuery rocks!

Java: Instanceof and Generics

Two options for runtime type checking with generics:

Option 1 - Corrupt your constructor

Let's assume you are overriding indexOf(...), and you want to check the type just for performance, to save yourself iterating the entire collection.

Make a filthy constructor like this:

public MyCollection<T>(Class<T> t) {

    this.t = t;

Then you can use isAssignableFrom to check the type.

public int indexOf(Object o) {

    if (
        o != null &&


    ) return -1;


Each time you instantiate your object you would have to repeat yourself:

new MyCollection<Apples>(Apples.class);

You might decide it isn't worth it. In the implementation of ArrayList.indexOf(...), they do not check that the type matches.

Option 2 - Let it fail

If you need to use an abstract method that requires your unknown type, then all you really want is for the compiler to stop crying about instanceof. If you have a method like this:

protected abstract void abstractMethod(T element);

You can use it like this:

public int indexOf(Object o) {

    try {

        abstractMethod((T) o);

    } catch (ClassCastException e) {


You are casting the object to T (your generic type), just to fool the compiler. Your cast does nothing at runtime, but you will still get a ClassCastException when you try to pass the wrong type of object into your abstract method.

NOTE 1: If you are doing additional unchecked casts in your abstract method, your ClassCastExceptions will get caught here. That could be good or bad, so think it through.

NOTE 2: You get a free null check when you use instanceof. Since you can't use it, you may need to check for null with your bare hands.

Draw horizontal rule in React Native

You can also try react-native-hr-component

npm i react-native-hr-component --save

Your code:

import Hr from 'react-native-hr-component'


<Hr text="Some Text" fontSize={5} lineColor="#eee" textPadding={5} textStyles={yourCustomStyles} hrStyles={yourCustomHRStyles} />

presentViewController and displaying navigation bar

try this

     let transition: CATransition = CATransition()
    let timeFunc : CAMediaTimingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
    transition.duration = 1
    transition.timingFunction = timeFunc
    transition.type = kCATransitionPush
    transition.subtype = kCATransitionFromRight
    self.view.window!.layer.addAnimation(transition, forKey: kCATransition)
    self.presentViewController(vc, animated:true, completion:nil)

Check if a value exists in pandas dataframe index

Multi index works a little different from single index. Here are some methods for multi-indexed dataframe.

df = pd.DataFrame({'col1': ['a', 'b','c', 'd'], 'col2': ['X','X','Y', 'Y'], 'col3': [1, 2, 3, 4]}, columns=['col1', 'col2', 'col3'])
df = df.set_index(['col1', 'col2'])

in df.index works for the first level only when checking single index value.

'a' in df.index     # True
'X' in df.index     # False

Check df.index.levels for other levels.

'a' in df.index.levels[0] # True
'X' in df.index.levels[1] # True

Check in df.index for an index combination tuple.

('a', 'X') in df.index  # True
('a', 'Y') in df.index  # False

Switching between GCC and Clang/LLVM using CMake

If the default compiler chosen by cmake is gcc and you have installed clang, you can use the easy way to compile your project with clang:

$ mkdir build && cd build
$ CXX=clang++ CC=clang cmake ..
$ make -j2

PHP Echo text Color

How about writing out some escape sequences?

echo "\033[01;31m Request has been sent. Please wait for my reply! \033[0m";

Won't work through browser though, only from console ;))

How do I find numeric columns in Pandas?

You can use the undocumented function _get_numeric_data() to filter only numeric columns:



In [32]: data
   A  B
0  1  s
1  2  s
2  3  s
3  4  s

In [33]: data._get_numeric_data()
0  1
1  2
2  3
3  4

Note that this is a "private method" (i.e., an implementation detail) and is subject to change or total removal in the future. Use with caution.

Case insensitive string compare in LINQ-to-SQL

Sometimes value stored in Database could contain spaces so running this could be fail

String.Equals(row.Name, "test", StringComparison.OrdinalIgnoreCase)

Solution to this problems is to remove space then convert its case then select like this

 return db.UsersTBs.Where(x => x.title.ToString().ToLower().Replace(" ",string.Empty).Equals(customname.ToLower())).FirstOrDefault();

Note in this case

customname is value to match with Database value

UsersTBs is class

title is the Database column

Trying to embed newline in a variable in bash

var="a b c"
for i in $var
   p=`echo -e "$p"'\n'$i`
echo "$p"

The solution was simply to protect the inserted newline with a "" during current iteration when variable substitution happens.

How to create python bytes object from long hex string?

You can do this with the hex codec. ie:

>>> s='000000000000484240FA063DE5D0B744ADBED63A81FAEA390000C8428640A43D5005BD44'
>>> s.decode('hex')

JavaScript to scroll long page to DIV

The property you need is location.hash. For example:

location.hash = 'top'; //would jump to named anchor "top

I don't know how to do the nice scroll animation without the use of dojo or some toolkit like that, but if you just need it to jump to an anchor, location.hash should do it.

(tested on FF3 and Safari 3.1.2)

How to get Wikipedia content using Wikipedia's API?

You can use the extract_html field of the summary REST endpoint for this: e.g.

Note: This aims to simply the content a bit by removing most of the pronunciations, mainly in parentheses in some cases.

Executing JavaScript without a browser?

FWIW, node.js comes with a shell, try typing in:


once you've installed node.js to see it in action. It's pretty standard to install rlwrap to get it to work nicely.

How to restart a single container with docker-compose

The answer's here are talking about the reflection of the change on the docker-compose.yml file.

But what if I want to incorporate the changes I have done in my code, and I believe that will be only possible by rebuilding the image and that I do with following commands

1. docker container stop

docker stop container-id

2. docker container removal

docker rm container-id

3. docker image removal

docker rmi image-id

4. compose the container again

docker-compose up container-name

How to give the background-image path in CSS?

You need to get 2 folders back from your css file.


background-image: url("../../images/image.png");

What is a classpath and how do I set it?

Setting the CLASSPATH System Variable

To display the current CLASSPATH variable, use these commands in Windows and UNIX (Bourne shell): In Windows: C:\> set CLASSPATH In UNIX: % echo $CLASSPATH

To delete the current contents of the CLASSPATH variable, use these commands: In Windows: C:\> set CLASSPATH= In UNIX: % unset CLASSPATH; export CLASSPATH

To set the CLASSPATH variable, use these commands (for example): In Windows: C:\> set CLASSPATH=C:\users\george\java\classes In UNIX: % CLASSPATH=/home/george/java/classes; export CLASSPATH

Add default value of datetime field in SQL Server to a timestamp

In SQLPlus while creating a table it is be like as

SQL> create table Test

 ( Test_ID number not null,
   Test_Date date default sysdate not null );

SQL> insert into Test(id) values (1);

 Test_ID Test_Date
       1 08-MAR-19

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver

Go through C:\apache-tomcat-7.0.47\lib path (this path may be differ based on where you installed the Tomcat server) then past ojdbc14.jar if its not contain.

Then restart the server in eclipse then run your app on server

Where does Console.WriteLine go in ASP.NET?

If you look at the Console class in .NET Reflector, you'll find that if a process doesn't have an associated console, Console.Out and Console.Error are backed by Stream.Null (wrapped inside a TextWriter), which is a dummy implementation of Stream that basically ignores all input, and gives no output.

So it is conceptually equivalent to /dev/null, but the implementation is more streamlined: there's no actual I/O taking place with the null device.

Also, apart from calling SetOut, there is no way to configure the default.

Update 2020-11-02: As this answer is still gathering votes in 2020, it should probably be noted that under ASP.NET Core, there usually is a console attached. You can configure the ASP.NET Core IIS Module to redirect all stdout and stderr output to a log file via the stdoutLogEnabled and stdoutLogFile settings:

  <aspNetCore processPath="dotnet"
              stdoutLogFile=".\logs\stdout" />

MySQL command line client for Windows

mysql.exe is included in mysql package. You don't have to install anything additionally.

load external URL into modal jquery ui dialog

EDIT: This answer might be outdated if you're using a recent version of jQueryUI.

For an anchor to trigger the dialog -

<a href="" class="example">

Here's the script -

$('a.example').click(function(){   //bind handlers
   var url = $(this).attr('href');

   return false;

$("#targetDiv").dialog({  //create dialog, but keep it closed
   autoOpen: false,
   height: 300,
   width: 350,
   modal: true

function showDialog(url){  //load content and open dialog

Copying one structure to another

You can memcpy structs, or you can just assign them like any other value.

struct {int a, b;} c, d;
c.a = c.b = 10;
d = c;

How to change style of a default EditText


<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="">
    <item android:drawable="@drawable/edittext_pressed" android:state_pressed="true" /> <!-- pressed -->
    <item android:drawable="@drawable/edittext_disable" android:state_enabled="false" /> <!-- focused -->
    <item android:drawable="@drawable/edittext_default" /> <!-- default -->


       <?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="" >
        <shape android:shape="rectangle" >
            <solid android:color="#BBDEFB" />
            <padding android:bottom="2dp" />
    <item android:bottom="5dp">
        <shape android:shape="rectangle" >
            <solid android:color="#fff" />

                android:right="0dp" />
        <shape android:shape="rectangle" >
            <solid android:color="#fff" />


 <?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="" >
        <shape android:shape="rectangle" >
            <solid android:color="#00f" />
            <padding android:bottom="2dp" />
    <item android:bottom="5dp">
        <shape android:shape="rectangle" >
            <solid android:color="#fff" />

                android:right="0dp" />
        <shape android:shape="rectangle" >
            <solid android:color="#fff" />



    <?xml version="1.0" encoding="utf-8"?>
    <layer-list xmlns:android="" >
            <shape android:shape="rectangle" >
                <solid android:color="#aaaaaa" />
                <padding android:bottom="2dp" />
        <item android:bottom="5dp">
            <shape android:shape="rectangle" >
                <solid android:color="#fff" />

                    android:right="0dp" />
            <shape android:shape="rectangle" >
                <solid android:color="#fff" />


it works fine without nine-patch Api 10+ enter image description here

How to get the ASCII value in JavaScript for the characters

Here is the example:

var charCode = "a".charCodeAt(0);_x000D_

Or if you have longer strings:

var string = "Some string";_x000D_
for (var i = 0; i < string.length; i++) {_x000D_

String.charCodeAt(x) method will return ASCII character code at a given position.

IIS 7, HttpHandler and HTTP Error 500.21

I had the same problem and was solved by running the following in run

%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i

Update Multiple Rows in Entity Framework from a list of ids

I think you are looking for below method:

var idList=new int[]{1, 2, 3, 4};
using (var db=new SomeDatabaseContext())
    var friends= db.Friends.Where(f=>idList.Contains(f.ID));
    await db.SaveChangesAsync();

This should be the efficient way of handling this.

How to delete cookies on an ASP.NET website

Taking the OP's Question title as deleting all cookies - "Delete Cookies in website"

I came across code from Dave Domagala on the web somewhere. I edited Dave's to allow for Google Analytics cookies too - which looped through all cookies found on the website and deleted them all. (From a developer angle - updating new code into an existing site, is a nice touch to avoid problems with users revisiting the site).

I use the below code in tandem with reading the cookies first, holding any required data - then resetting the cookies after washing everything clean with the below loop.

The code:

int limit = Request.Cookies.Count; //Get the number of cookies and 
                                   //use that as the limit.
HttpCookie aCookie;   //Instantiate a cookie placeholder
string cookieName;   

//Loop through the cookies
for(int i = 0; i < limit; i++)
 cookieName = Request.Cookies[i].Name;    //get the name of the current cookie
 aCookie = new HttpCookie(cookieName);    //create a new cookie with the same
                                          // name as the one you're deleting
 aCookie.Value = "";    //set a blank value to the cookie 
 aCookie.Expires = DateTime.Now.AddDays(-1);    //Setting the expiration date
                                                //in the past deletes the cookie

 Response.Cookies.Add(aCookie);    //Set the cookie to delete it.

Addition: If You Use Google Analytics

The above loop/delete will delete ALL cookies for the site, so if you use Google Analytics - it would probably be useful to hold onto the __utmz cookie as this one keeps track of where the visitor came from, what search engine was used, what link was clicked on, what keyword was used, and where they were in the world when your website was accessed.

So to keep it, wrap a simple if statement once the cookie name is known:

aCookie = new HttpCookie(cookieName);    
if (aCookie.Name != "__utmz")
    aCookie.Value = "";    //set a blank value to the cookie 
    aCookie.Expires = DateTime.Now.AddDays(-1);   


How to call a MySQL stored procedure from within PHP code?

    $res = mysql_query('SELECT getTreeNodeName(1) AS result');
    if ($res === false) {
        echo mysql_errno().': '.mysql_error();
    while ($obj = mysql_fetch_object($res)) {
        echo $obj->result;

How to set a JavaScript breakpoint from code in Chrome?

I wouldn't recommend debugger; if you just want to kill and stop the javascript code, since debugger; will just temporally freeze your javascript code and not stop it permanently.

If you want to properly kill and stop javascript code at your command use the following:

throw new Error("This error message appears because I placed it");

How can I reload .emacs after changing it?

Keyboard shortcut:

(defun reload-init-file ()
  (load-file user-init-file))

(global-set-key (kbd "C-c C-l") 'reload-init-file)    ; Reload .emacs file

How to convert a String to JsonObject using gson library

String emailData = {"to": "[email protected]","subject":"User details","body": "The user has completed his training"

// Java model class
public class EmailData {
    public String to;
    public String subject;
    public String body;

//Final Data
Gson gson = new Gson();  
EmailData emaildata = gson.fromJson(emailData, EmailData.class);

React - Display loading screen while DOM is rendering?

You can easily do that by using lazy loading in react. For that you have to use lazy and suspense from react like that.

import React, { lazy, Suspense } from 'react';

const loadable = (importFunc, { fallback = null } = { fallback: null }) => {
  const LazyComponent = lazy(importFunc);

  return props => (
    <Suspense fallback={fallback}>
      <LazyComponent {...props} />

export default loadable;

After that export your components like this.

export const TeacherTable = loadable(() =>
  import ('./MainTables/TeacherTable'), {
    fallback: <Loading />,

And then in your routes file use it like this.

 <Route exact path="/app/view/teachers" component={TeacherTable} />

Thats it now you are good to go everytime your DOM is rendering your Loading compnent will be displayed as we have specified in the fallback property above. Just make sure that you do any ajax request only in componentDidMount()

An Authentication object was not found in the SecurityContext - Spring 3.2.2

This could also happens if you put a @PreAuthorize or @PostAuthorize in a Bean in creation. I would recommend to move such annotations to methods of interest.

Java image resize, maintain aspect ratio

Just add one more block to Ozzy's code so the thing looks like this:

public static Dimension getScaledDimension(Dimension imgSize,Dimension boundary) {

    int original_width = imgSize.width;
    int original_height = imgSize.height;
    int bound_width = boundary.width;
    int bound_height = boundary.height;
    int new_width = original_width;
    int new_height = original_height;

    // first check if we need to scale width
    if (original_width > bound_width) {
        //scale width to fit
        new_width = bound_width;
        //scale height to maintain aspect ratio
        new_height = (new_width * original_height) / original_width;

    // then check if we need to scale even with the new height
    if (new_height > bound_height) {
        //scale height to fit instead
        new_height = bound_height;
        //scale width to maintain aspect ratio
        new_width = (new_height * original_width) / original_height;
    // upscale if original is smaller
    if (original_width < bound_width) {
        //scale width to fit
        new_width = bound_width;
        //scale height to maintain aspect ratio
        new_height = (new_width * original_height) / original_width;

    return new Dimension(new_width, new_height);
} Getting the error "Access to the path is denied." while trying to upload files to my Windows Server 2008 R2 Web server

Your account {MACHINE}\ASPNET does not have write access to that location. That is the reason why its failing.

Consider granting access rights to the resource to the ASP.NET request identity.

Right click on downloading folder Properties > Security Tab > Edit > Add > locations > choose your local machine > click OK > Type ASPNET below "Enter the object name to select" > Click Check Names Check the boxes for the desired access (Full Control). If it will not work for you do the same with Network Service

Now this should show your local {MACHINENAME}\ASPNET account, then you set the write permission to this account.

Otherwise if the application is impersonating via <identity impersonate="true"/>, the identity will be the anonymous user (typically IUSR_MACHINENAME) or the authenticated request user.

Or just use dedicated location for storing files in ASP.NET which is App_Data. To create it right click on your ASP.NET Project (in Visual Studio) Add > Add ASP.NET Folder > App_Data. Then you'll be able to save data to this location:

var path = Server.MapPath("~/App_Data/file.txt");
System.IO.File.WriteAllText(path, "Hello World");

add string to String array

You cannot resize an array in java.

Once the size of array is declared, it remains fixed.

Instead you can use ArrayList that has dynamic size, meaning you don't need to worry about its size. If your array list is not big enough to accommodate new values then it will be resized automatically.

ArrayList<String> ar = new ArrayList<String>();
String s1 ="Test1";
String s2 ="Test2";
String s3 ="Test3";

String s4 ="Test4";

How to find rows that have a value that contains a lowercase letter

--For Sql

FROM tablename
WHERE tablecolumnname LIKE '%[a-z]%';

How can I create a temp file with a specific extension with .NET?

The MSDN documentation for C++'s GetTempFileName discusses your concern and answers it:

GetTempFileName is not able to guarantee that the file name is unique.

Only the lower 16 bits of the uUnique parameter are used. This limits GetTempFileName to a maximum of 65,535 unique file names if the lpPathName and lpPrefixString parameters remain the same.

Due to the algorithm used to generate file names, GetTempFileName can perform poorly when creating a large number of files with the same prefix. In such cases, it is recommended that you construct unique file names based on GUIDs.

How to get a value from the last inserted row?

Here is how I solved it, based on the answers here:

Connection conn = ConnectToDB(); //ConnectToDB establishes a connection to the database.
String sql = "INSERT INTO \"TableName\"" +
        "(\"Column1\", \"Column2\",\"Column3\",\"Column4\")" +
        "VALUES ('value1',value2, 'value3', 'value4') RETURNING 
PreparedStatement prpState = conn.prepareStatement(sql);
ResultSet rs = prpState.executeQuery();

Git Push error: refusing to update checked out branch


You cannot push to the one checked out branch of a repository because it would mess with the user of that repository in a way that will most probably end with loss of data and history. But you can push to any other branch of the same repository.

As bare repositories never have any branch checked out, you can always push to any branch of a bare repository.

Autopsy of the problem

When a branch is checked out, committing will add a new commit with the current branch's head as its parent and move the branch's head to be that new commit.


A ? B


A ? B ? C

But if someone could push to that branch inbetween, the user would get itself in what git calls detached head mode:

A ? B ? X
    ?   ?
[HEAD] [branch1]

Now the user is not in branch1 anymore, without having explicitly asked to check out another branch. Worse, the user is now outside any branch, and any new commit will just be dangling:

A ? B ? X

Hypothetically, if at this point, the user checks out another branch, then this dangling commit becomes fair game for Git's garbage collector.

How to access the request body when POSTing using Node.js and Express?

As of Express 4, the following code appears to do the trick. Note that you'll need to install body-parser using npm.

var express = require('express');
var bodyParser = require('body-parser');
var app = express();
app.use(bodyParser.urlencoded({ extended: false }));

app.listen(8888);'/update', function(req, res) {
    console.log(req.body); // the posted data

How to terminate process from Python using pid?

I wanted to do the same thing as, but I wanted to do it in the one file.

So the logic would be:

  • if a script with my name is running, kill it, then exit
  • if a script with my name is not running, do stuff

I modified the answer by Bakuriu and came up with this:

from os import getpid
from sys import argv, exit
import psutil  ## pip install psutil

myname = argv[0]
mypid = getpid()
for process in psutil.process_iter():
    if != mypid:
        for path in process.cmdline():
            if myname in path:
                print "process found"

## your program starts here...

Running the script will do whatever the script does. Running another instance of the script will kill any existing instance of the script.

I use this to display a little PyGTK calendar widget which runs when I click the clock. If I click and the calendar is not up, the calendar displays. If the calendar is running and I click the clock, the calendar disappears.

How can I convert integer into float in Java?

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

float z = x * 1.0 / y;

How to declare a type as nullable in TypeScript?

type MyProps = {
  workoutType: string | null;

CSS/HTML: Create a glowing border around an Input Field

$('.form-fild input,.form-fild textarea').focus(function() {_x000D_
$('.form-fild input,.form-fild textarea').blur(function() {_x000D_
.open {_x000D_
  color:red;   _x000D_
.form-fild {_x000D_
 position: relative;_x000D_
 margin: 30px 0;_x000D_
.form-fild label {_x000D_
 position: absolute;_x000D_
 top: 5px;_x000D_
 left: 10px;_x000D_
_x000D_ label {_x000D_
 top: -25px;_x000D_
 left: 10px;_x000D_
 /*background: #ffffff;*/_x000D_
.form-fild input[type="text"] {_x000D_
 padding-left: 80px;_x000D_
.form-fild textarea {_x000D_
 padding-left: 80px;_x000D_
}_x000D_ textarea, _x000D_ input[type="text"] {_x000D_
 padding-left: 10px;_x000D_
input[type="text"] {_x000D_
 padding: 10px;_x000D_
 width: 100%;_x000D_
input,_x000D_ label,_x000D_
.form-fild label {_x000D_
 -webkit-transition: all 0.2s ease-in-out;_x000D_
       -moz-transition: all 0.2s ease-in-out;_x000D_
         -o-transition: all 0.2s ease-in-out;_x000D_
            transition: all 0.2s ease-in-out;_x000D_
<script src=""></script>_x000D_
<div class="container">_x000D_
 <div class="row">_x000D_
        <div class="form-fild">_x000D_
            <label>Name :</label>_x000D_
            <input type="text">_x000D_
        <div class="form-fild">_x000D_
            <label>Email :</label>_x000D_
            <input type="text">_x000D_
        <div class="form-fild">_x000D_
            <label>Number :</label>_x000D_
            <input type="text">_x000D_
        <div class="form-fild">_x000D_
            <label>Message :</label>_x000D_
            <textarea cols="10" rows="5"></textarea>_x000D_

Cannot implicitly convert type from Task<>

The main issue with your example that you can't implicitly convert Task<T> return types to the base T type. You need to use the Task.Result property. Note that Task.Result will block async code, and should be used carefully.

Try this instead:

public List<int> TestGetMethod()  
    return GetIdList().Result;  

How do I find out my root MySQL password?

Hmm Mysql 5.7.13 to reset all I did was:

$ sudo service mysql stop To stop mysql

$ mysqld_safe --skip-grant-tables & Start mysql

$ mysql -u root

Just like the correct answer. Then all I did was do what @eebbesen did.

mysql> SET PASSWORD FOR root@'localhost' = PASSWORD('NEW-password-HERE');

Hope it helps anyone out there :)

Remove an item from array using UnderscoreJS

By Using underscore.js

var arr = [{id:1,name:'a'},{id:2,name:'b'},{id:3,name:'c'}];

var resultArr = _.reject(arr,{id:3});


The result will be :: [{id:1name:'a'},{id:2,name:'c'}]

Error: package or namespace load failed for ggplot2 and for data.table

These steps work for me:

  1. Download the Rcpp manually from WebSite (
  2. unzip the folder/files to "Rcpp" folder
  3. Locate the "library" folder under R install directory Ex: C:\R\R-3.3.1\library
  4. Copy the "Rcpp" folder to Library folder.

Good to go!!!



The ON UPDATE and ON DELETE specify which action will execute when a row in the parent table is updated and deleted. The following are permitted actions : NO ACTION, CASCADE, SET NULL, and SET DEFAULT.

Delete actions of rows in the parent table

If you delete one or more rows in the parent table, you can set one of the following actions:

  • ON DELETE NO ACTION: SQL Server raises an error and rolls back the delete action on the row in the parent table.
  • ON DELETE CASCADE: SQL Server deletes the rows in the child table that is corresponding to the row deleted from the parent table.
  • ON DELETE SET NULL: SQL Server sets the rows in the child table to NULL if the corresponding rows in the parent table are deleted. To execute this action, the foreign key columns must be nullable.
  • ON DELETE SET DEFAULT: SQL Server sets the rows in the child table to their default values if the corresponding rows in the parent table are deleted. To execute this action, the foreign key columns must have default definitions. Note that a nullable column has a default value of NULL if no default value specified. By default, SQL Server appliesON DELETE NO ACTION if you don’t explicitly specify any action.

Update action of rows in the parent table

If you update one or more rows in the parent table, you can set one of the following actions:

  • ON UPDATE NO ACTION: SQL Server raises an error and rolls back the update action on the row in the parent table.
  • ON UPDATE CASCADE: SQL Server updates the corresponding rows in the child table when the rows in the parent table are updated.
  • ON UPDATE SET NULL: SQL Server sets the rows in the child table to NULL when the corresponding row in the parent table is updated. Note that the foreign key columns must be nullable for this action to execute.
  • ON UPDATE SET DEFAULT: SQL Server sets the default values for the rows in the child table that have the corresponding rows in the parent table updated.
FOREIGN KEY (foreign_key_columns)
    REFERENCES parent_table(parent_key_columns)
    ON UPDATE <action> 
    ON DELETE <action>;

See the reference tutorial.

How to add a "confirm delete" option in ASP.Net Gridview?

Try this:

I used for Update and Delete buttons. It doesn't touch Edit button. You can use auto generated buttons.

  protected void gvOperators_OnRowDataBound(object sender, GridViewRowEventArgs e)
        if(e.Row.RowType != DataControlRowType.DataRow) return;
        var updateButton = (LinkButton)e.Row.Cells[0].Controls[0];
        if (updateButton.Text == "Update")
            updateButton.OnClientClick = "return confirm('Do you really want to update?');";
        var deleteButton = (LinkButton)e.Row.Cells[0].Controls[2];
        if (deleteButton.Text == "Delete")
            deleteButton.OnClientClick = "return confirm('Do you really want to delete?');";


Centering a background image, using CSS

if your not satisfied with the answers above then use this

    * {margin: 0;padding: 0;}

        height: 100%;

        background-image: url("background.png");
        background-repeat: no-repeat;
        background-position: center center;
        background-size: 80%;

How to set enum to null

Color? color = null;

or you can use

Color? color = new Color?();

example where assigning null wont work

color = x == 5 ? Color.Red : x == 9 ? Color.Black : null ; 

so you can use :

 color = x == 5 ? Color.Red : x == 9 ? Color.Black : new Color?(); 

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

Right click on the stored procedure and select Script Stored Procedure as | CREATE To | New Query Editor Window / Clipboard / File.

You can also do Modify when you right click on the stored procedure.

For multiple procedures at once, click on the Stored Procedures folder, hit F7 to open the Object Explorer Details pane, hold Ctrl and click to select all the ones that you want, and then right click and select Script Stored Procedure as | CREATE To.

"Input string was not in a correct format."

If you are not validating explicitly for numbers in the text field, in any case its better to use

int result=0;
if(int.TryParse(textBox1.Text,out result))

Now if the result is success then you can proceed with your calculations.

Didn't find class ""?

I have also face the same issue after trying all solution I found the below solution.

If you have applied proguard rules then add below line in ProGuard Rules

-keep class

and its solve my problem.

Cannot obtain value of local or argument as it is not available at this instruction pointer, possibly because it has been optimized away

As an additional answer for those experiencing this issue when debugging an Azure websites' web app:

When deploying from GitHub, for example, the code is compiled in Azure server optimized by default.

I tell the server to compile in a debuggable way by setting SCM_BUILD_ARGS to /p:Configuration=Debug

but there are more options. See this:

Copy files to network computers on windows command line

Below command will work in command prompt:

copy c:\folder\file.ext \\dest-machine\destfolder /Z /Y

To Copy all files:

copy c:\folder\*.* \\dest-machine\destfolder /Z /Y

REST / SOAP endpoints for a WCF service

MSDN seems to have an article for this now:


By default, Windows Communication Foundation (WCF) makes endpoints available only to SOAP clients. In How to: Create a Basic WCF Web HTTP Service, an endpoint is made available to non-SOAP clients. There may be times when you want to make the same contract available both ways, as a Web endpoint and as a SOAP endpoint. This topic shows an example of how to do this.

Boolean operators && and ||

&& and || are what is called "short circuiting". That means that they will not evaluate the second operand if the first operand is enough to determine the value of the expression.

For example if the first operand to && is false then there is no point in evaluating the second operand, since it can't change the value of the expression (false && true and false && false are both false). The same goes for || when the first operand is true.

You can read more about this here: From the table on that page you can see that && is equivalent to AndAlso in VB.NET, which I assume you are referring to.

JSON Post with Customized HTTPHeader Field

I tried as you mentioned, but only first parameter is going through and rest all are appearing in the server as undefined. I am passing JSONWebToken as part of header.

    url: 'api/outletadd',
    type: 'post',
    data: { outletname:outletname , addressA:addressA , addressB:addressB, city:city , postcode:postcode , state:state , country:country , menuid:menuid },
    headers: {
        authorization: storedJWT
    dataType: 'json',
    success: function (data){
        alert("Outlet Created");
    error: function (data){
        alert("Outlet Creation Failed, please try again.");        


Tracing XML request/responses with JAX-WS

There are various ways of doing this programmatically, as described in the other answers, but they're quite invasive mechanisms. However, if you know that you're using the JAX-WS RI (aka "Metro"), then you can do this at the configuration level. See here for instructions on how to do this. No need to mess about with your application.

How to "properly" create a custom object in JavaScript?

To continue off of bobince's answer

In es6 you can now actually create a class

So now you can do:

class Shape {
    constructor(x, y) {
        this.x = x;
        this.y = y;

    toString() {
        return `Shape at ${this.x}, ${this.y}`;

So extend to a circle (as in the other answer) you can do:

class Circle extends Shape {
    constructor(x, y, r) {
        super(x, y);
        this.r = r;

    toString() {
        let shapeString = super.toString();
        return `Circular ${shapeString} with radius ${this.r}`;

Ends up a bit cleaner in es6 and a little easier to read.

Here is a good example of it in action:

class Shape {_x000D_
  constructor(x, y) {_x000D_
    this.x = x;_x000D_
    this.y = y;_x000D_
  toString() {_x000D_
    return `Shape at ${this.x}, ${this.y}`;_x000D_
class Circle extends Shape {_x000D_
  constructor(x, y, r) {_x000D_
    super(x, y);_x000D_
    this.r = r;_x000D_
  toString() {_x000D_
    let shapeString = super.toString();_x000D_
    return `Circular ${shapeString} with radius ${this.r}`;_x000D_
let c = new Circle(1, 2, 4);_x000D_
console.log('' + c, c);

Set default format of datetimepicker as dd-MM-yyyy

Try this,

string Date = datePicker1.SelectedDate.Value.ToString("dd-MMM-yyyy");

It worked for me the output format will be '02-May-2016'

HTML - Change\Update page contents without refreshing\reloading the page

You've got the right idea, so here's how to go ahead: the onclick handlers run on the client side, in the browser, so you cannot call a PHP function directly. Instead, you need to add a JavaScript function that (as you mentioned) uses AJAX to call a PHP script and retrieve the data. Using jQuery, you can do something like this:

<script type="text/javascript">
function recp(id) {
  $('#myStyle').load('data.php?id=' + id);

<a href="#" onClick="recp('1')" > One   </a>
<a href="#" onClick="recp('2')" > Two   </a>
<a href="#" onClick="recp('3')" > Three </a>

<div id='myStyle'>

Then you put your PHP code into a separate file: (I've called it data.php in the above example)

  require ('myConnect.php');     
  $id = $_GET['id'];
  $results = mysql_query("SELECT para FROM content WHERE  para_ID='$id'");   
  if( mysql_num_rows($results) > 0 )
   $row = mysql_fetch_array( $results );
   echo $row['para'];

Retrofit 2: Get JSON from Response body

If you don't have idea about What could be the response from the API. Follow the steps to convert the responsebody response value into bytes and print in the String format You can get the entire response printed in the console.

Then you can convert string to JSONObject easily.

      apiService.getFeeds(headerMap, map).enqueue(object : Callback, retrofit2.Callback<ResponseBody> {
            override fun onFailure(call: Call<ResponseBody>?, t: Throwable?) {

            override fun onResponse(call: Call<ResponseBody>?, response: Response<ResponseBody>?) {
                val bytes = (response!!.body()!!.bytes())
                Log.d("Retrofit Success : ", ""+ String(bytes))

Plotting categorical data with pandas and matplotlib

You might find useful mosaic plot from statsmodels. Which can also give statistical highlighting for the variances.

from import mosaic
plt.rcParams['font.size'] = 16.0
mosaic(df, ['direction', 'colour']);

enter image description here

But beware of the 0 sized cell - they will cause problems with labels.

See this answer for details

Rename Files and Directories (Add Prefix)

This could be done running a simple find command:

find * -maxdepth 0 -exec mv {} PRE_{} \;

The above command will prefix all files and folders in the current directory with PRE_.

Java way to check if a string is palindrome

Here's a good class :

public class Palindrome {

  public static boolean isPalindrome(String stringToTest) {
    String workingCopy = removeJunk(stringToTest);
    String reversedCopy = reverse(workingCopy);

    return reversedCopy.equalsIgnoreCase(workingCopy);

  protected static String removeJunk(String string) {
    int i, len = string.length();
    StringBuffer dest = new StringBuffer(len);
    char c;

    for (i = (len - 1); i >= 0; i--) {
      c = string.charAt(i);
      if (Character.isLetterOrDigit(c)) {

    return dest.toString();

  protected static String reverse(String string) {
    StringBuffer sb = new StringBuffer(string);

    return sb.reverse().toString();

  public static void main(String[] args) {
    String string = "Madam, I'm Adam.";

    System.out.println("Testing whether the following "
        + "string is a palindrome:");
    System.out.println("    " + string);

    if (isPalindrome(string)) {
      System.out.println("It IS a palindrome!");
    } else {
      System.out.println("It is NOT a palindrome!");


Java JRE 64-bit download for Windows?

You can also just search on sites like Tucows and CNET, they have it there too.

what is the difference between json and xml

The fundamental difference, which no other answer seems to have mentioned, is that XML is a markup language (as it actually says in its name), whereas JSON is a way of representing objects (as also noted in its name).

A markup language is a way of adding extra information to free-flowing plain text, e.g

Here is some text.

With XML (using a certain element vocabulary) you can put:

    <Paragraph Align="Center">
        Here <Bold>is</Bold> some text.

This is what makes markup languages so useful for representing documents.

An object notation like JSON is not as flexible. But this is usually a good thing. When you're representing objects, you simply don't need the extra flexibility. To represent the above example in JSON, you'd actually have to solve some problems manually that XML solves for you.

    "Paragraphs": [
            "align": "center",
            "content": [
                "Here ", {
                    "style" : "bold",
                    "content": [ "is" ]
                " some text."

It's not as nice as the XML, and the reason is that we're trying to do markup with an object notation. So we have to invent a way to scatter snippets of plain text around our objects, using "content" arrays that can hold a mixture of strings and nested objects.

On the other hand, if you have typical a hierarchy of objects and you want to represent them in a stream, JSON is better suited to this task than HTML.

    "firstName": "Homer",
    "lastName": "Simpson",
    "relatives": [ "Grandpa", "Marge", "The Boy", "Lisa", "I think that's all of them" ]

Here's the logically equivalent XML:

        <Relative>The Boy</Relative>
        <Relative>I think that's all of them</Relative>

JSON looks more like the data structures we declare in programming languages. Also it has less redundant repetition of names.

But most importantly of all, it has a defined way of distinguishing between a "record" (items unordered, identified by names) and a "list" (items ordered, identified by position). An object notation is practically useless without such a distinction. And XML has no such distinction! In my XML example <Person> is a record and <Relatives> is a list, but they are not identified as such by the syntax.

Instead, XML has "elements" versus "attributes". This looks like the same kind of distinction, but it's not, because attributes can only have string values. They cannot be nested objects. So I couldn't have applied this idea to <Person>, because I shouldn't have to turn <Relatives> into a single string.

By using an external schema, or extra user-defined attributes, you can formalise a distinction between lists and records in XML. The advantage of JSON is that the low-level syntax has that distinction built into it, so it's very succinct and universal. This means that JSON is more "self describing" by default, which is an important goal of both formats.

So JSON should be the first choice for object notation, where XML's sweet spot is document markup.

Unfortunately for XML, we already have HTML as the world's number one rich text markup language. An attempt was made to reformulate HTML in terms of XML, but there isn't much advantage in this.

So XML should (in my opinion) have been a pretty limited niche technology, best suited only for inventing your own rich text markup languages if you don't want to use HTML for some reason. The problem was that in 1998 there was still a lot of hype about the Web, and XML became popular due to its superficial resemblance to HTML. It was a strange design choice to try to apply to hierarchical data a syntax actually designed for convenient markup.

How to know Laravel version and where is it defined?

Run this command in your project folder location in cmd

php artisan --version

jQuery: print_r() display equivalent?

You could use very easily reflection to list all properties, methods and values.

For Gecko based browsers you can use the .toSource() method:

var data = new Object();
data["firstname"] = "John";
data["lastname"] = "Smith";
data["age"] = 21;

alert(data.toSource()); //Will return "({firstname:"John", lastname:"Smith", age:21})"

But since you use Firebug, why not just use console.log?

Fastest way to reset every value of std::vector<int> to 0

I had the same question but about rather short vector<bool> (afaik the standard allows to implement it internally differently than just a continuous array of boolean elements). Hence I repeated the slightly modified tests by Fabio Fracassi. The results are as follows (times, in seconds):

            -O0       -O3
         --------  --------
memset     0.666     1.045
fill      19.357     1.066
iterator  67.368     1.043
assign    17.975     0.530
for i     22.610     1.004

So apparently for these sizes, vector<bool>::assign() is faster. The code used for tests:

#include <vector>
#include <cstring>
#include <cstdlib>

#define TEST_METHOD 5
const size_t TEST_ITERATIONS = 34359738;
const size_t TEST_ARRAY_SIZE = 200;

using namespace std;

int main(int argc, char** argv) {

    std::vector<int> v(TEST_ARRAY_SIZE, 0);

    for(size_t i = 0; i < TEST_ITERATIONS; ++i) {
#if TEST_METHOD == 1
        memset(&v[0], false, v.size() * sizeof v[0]);
#elif TEST_METHOD == 2
        std::fill(v.begin(), v.end(), false);
   #elif TEST_METHOD == 3
        for (std::vector<int>::iterator it=v.begin(), end=v.end(); it!=end; ++it) {
            *it = 0;
   #elif TEST_METHOD == 4
   #elif TEST_METHOD == 5
      for (size_t i = 0; i < TEST_ARRAY_SIZE; i++) {
          v[i] = false;

    return EXIT_SUCCESS;

I used GCC 7.2.0 compiler on Ubuntu 17.10. The command line for compiling:

g++ -std=c++11 -O0 main.cpp
g++ -std=c++11 -O3 main.cpp

Can I pass a JavaScript variable to another browser window?

Yes, scripts can access properties of other windows in the same domain that they have a handle on (typically gained through and window.frames/parent). It is usually more manageable to call functions defined on the other window rather than fiddle with variables directly.

However, windows can die or move on, and browsers deal with it differently when they do. Check that a window (a) is still open (!window.closed) and (b) has the function you expect available, before you try to call it.

Simple values like strings are fine, but generally it isn't a good idea to pass complex objects such as functions, DOM elements and closures between windows. If a child window stores an object from its opener, then the opener closes, that object can become 'dead' (in some browsers such as IE), or cause a memory leak. Weird errors can ensue.

Moment.js - How to convert date string into date?

If you are getting a JS based date String then first use the new Date(String) constructor and then pass the Date object to the moment method. Like:

var dateString = 'Thu Jul 15 2016 19:31:44 GMT+0200 (CEST)';
var dateObj = new Date(dateString);
var momentObj = moment(dateObj);
var momentString = momentObj.format('YYYY-MM-DD'); // 2016-07-15

In case dateString is 15-07-2016, then you should use the moment(date:String, format:String) method

var dateString = '07-15-2016';
var momentObj = moment(dateString, 'MM-DD-YYYY');
var momentString = momentObj.format('YYYY-MM-DD'); // 2016-07-15

How can I do an OrderBy with a dynamic string parameter?

You need to use the LINQ Dynamic Query Library in order to pass parameters at runtime,

This will allow linq statements like

string orderedBy = "Description";
var query = (from p in products
            select p);

Use a normal link to submit a form

you can use OnClick="document.getElementById('formID_NOT_NAME').SUBMIT()"

How to Lock the data in a cell in excel using vba

Sub LockCells()


Selection.Locked = True

Selection.FormulaHidden = False

ActiveSheet.Protect DrawingObjects:=False, Contents:=True, Scenarios:= False, AllowFormattingCells:=True, AllowFormattingColumns:=True, AllowFormattingRows:=True, AllowInsertingColumns:=True, AllowInsertingRows:=True, AllowInsertingHyperlinks:=True, AllowDeletingColumns:=True, AllowDeletingRows:=True, AllowSorting:=True, AllowFiltering:=True, AllowUsingPivotTables:=True

End Sub

jQuery: Handle fallback for failed AJAX Request

I prefer to this approach because you can return the promise and use .then(successFunction, failFunction); anywhere you need to.

var promise = $.ajax({
    type: 'GET',
    dataType: 'json',
    url: url,
    timeout: 5000
  }).then(function( data, textStatus, jqXHR ) {
    alert('request successful');
  }, function( jqXHR, textStatus, errorThrown ) {
    alert('request failed');

//also access the success and fail using variable
promise.then(successFunction, failFunction);

Calculate the display width of a string in Java

It doesn't always need to be toolkit-dependent or one doesn't always need use the FontMetrics approach since it requires one to first obtain a graphics object which is absent in a web container or in a headless enviroment.

I have tested this in a web servlet and it does calculate the text width.

import java.awt.Font;
import java.awt.font.FontRenderContext;
import java.awt.geom.AffineTransform;


String text = "Hello World";
AffineTransform affinetransform = new AffineTransform();     
FontRenderContext frc = new FontRenderContext(affinetransform,true,true);     
Font font = new Font("Tahoma", Font.PLAIN, 12);
int textwidth = (int)(font.getStringBounds(text, frc).getWidth());
int textheight = (int)(font.getStringBounds(text, frc).getHeight());

Add the necessary values to these dimensions to create any required margin.

BAT file: Open new cmd window and execute a command in there

You may already find your answer because it was some time ago you asked. But I tried to do something similar when coding ror. I wanted to run "rails server" in a new cmd window so I don't have to open a new cmd and then find my path again.

What I found out was to use the K switch like this:

start cmd /k echo Hello, World!

start before "cmd" will open the application in a new window and "/K" will execute "echo Hello, World!" after the new cmd is up.

You can also use the /C switch for something similar.

start cmd /C pause

This will then execute "pause" but close the window when the command is done. In this case after you pressed a button. I found this useful for "rails server", then when I shutdown my dev server I don't have to close the window after.

Use the following in your batch file:

start cmd.exe /c "more-batch-commands-here"


start cmd.exe /k "more-batch-commands-here"

/c Carries out the command specified by string and then terminates

/k Carries out the command specified by string but remains

The /c and /k options controls what happens once your command finishes running. With /c the terminal window will close automatically, leaving your desktop clean. With /k the terminal window will remain open. It's a good option if you want to run more commands manually afterwards.

Consult the cmd.exe documentation using cmd /? for more details.

Escaping Commands with White Spaces

The proper formatting of the command string becomes more complicated when using arguments with spaces. See the examples below. Note the nested double quotes in some examples.


Run a program and pass a filename parameter:
CMD /c write.exe c:\docs\sample.txt

Run a program and pass a filename which contains whitespace:
CMD /c write.exe "c:\sample documents\sample.txt"

Spaces in program path:
CMD /c ""c:\Program Files\Microsoft Office\Office\Winword.exe""

Spaces in program path + parameters:
CMD /c ""c:\Program Files\demo.cmd"" Parameter1 Param2
CMD /k ""c:\batch files\demo.cmd" "Parameter 1 with space" "Parameter2 with space""

Launch demo1 and demo2:
CMD /c ""c:\Program Files\demo1.cmd" & "c:\Program Files\demo2.cmd""


Converting Integers to Roman Numerals - Java

private String convertToRoman(int num) {
  String result = "";
  while(num > 0){
    if(num >= 1000){
        result += "M";
        num -= 1000;
    }else if(num >= 900){
        result += "CM";
        num -= 900;
    else if(num >= 500){
        result += "D";
        num -= 500;
    }else if(num >= 400){
        result += "CD";
        num -= 400;
    }else if(num >= 100){
        result += "C";
        num -= 100;
    }else if(num >= 90){
        result += "XC";
        num -= 90;
    }else if(num >= 50){
        result += "L";
        num -= 50;
    }else if(num >= 40){
        result += "XL";
        num -= 40;
    else if(num >= 10){
        result += "X";
        num -= 10;
    }else if(num >= 9){
        result += "IX";
        num -= 9;
    else if(num >= 5){
        result += "V";
        num -= 5;
    }else if(num >= 4){
        result += "IV";
        num -= 4;
    }else if(num >= 1){
        result += "I";
        num -= 1;


  return result;

Read text from response

I've just tried that myself, and it gave me a 200 OK response, but no content - the content length was 0. Are you sure it's giving you content? Anyway, I'll assume that you've really got content.

Getting actual text back relies on knowing the encoding, which can be tricky. It should be in the Content-Type header, but then you've got to parse it etc.

However, if this is actually XML (e.g. from ""), it's a lot easier. Just load the XML into memory, e.g. via LINQ to XML. For example:

using System;
using System.IO;
using System.Net;
using System.Xml.Linq;
using System.Web;

class Test
    static void Main()
        string url = "";
        HttpWebRequest request = (HttpWebRequest) WebRequest.Create(url);

        XDocument doc;
        using (WebResponse response = request.GetResponse())
            using (Stream stream = response.GetResponseStream())
                doc = XDocument.Load(stream);
        // Now do whatever you want with doc here

If the content is XML, getting the result into an XML object model (whether it's XDocument, XmlDocument or XmlReader) is likely to be more valuable than having the plain text.

Apache Cordova - uninstall globally

Super late here and I still couldn't uninstall using sudo as the other answers suggest. What did it for me was checking where cordova was installed by running

which cordova

it will output something like this


then removing by

rm -rf /usr/local/bin/cordova

how do I set height of container DIV to 100% of window height?

You can net set it to view height

html, body
    height: 100vh;

Best way to get hostname with php

For PHP >= 5.3.0 use this:

$hostname = gethostname();

For PHP < 5.3.0 but >= 4.2.0 use this:

$hostname = php_uname('n');

For PHP < 4.2.0 use this:

$hostname = getenv('HOSTNAME'); 
if(!$hostname) $hostname = trim(`hostname`); 
if(!$hostname) $hostname = exec('echo $HOSTNAME');
if(!$hostname) $hostname = preg_replace('#^\w+\s+(\w+).*$#', '$1', exec('uname -a')); 

MySQL "WITH" clause

Update: MySQL 8.0 is finally getting the feature of common table expressions, including recursive CTEs.

Here's a blog announcing it:

Below is my earlier answer, which I originally wrote in 2008.

MySQL 5.x does not support queries using the WITH syntax defined in SQL-99, also called Common Table Expressions.

This has been a feature request for MySQL since January 2006:

Other RDBMS products that support common table expressions:

Getting "error": "unsupported_grant_type" when trying to get a JWT by calling an OWIN OAuth secured Web Api via Postman

With Postman, select Body tab and choose the raw option and type the following:


Sending HTML Code Through JSON

Do Like this

1st put all your HTML content to array, then do json_encode

$html_content="<p>hello this is sample text";

echo json_encode($json_array);

Angular checkbox and ng-click

You can use ng-change instead of ng-click:

<!doctype html>
  <script src=""></script>
        var app = angular.module('myapp', []);
        app.controller('mainController', function($scope) {
          $scope.vm = {};
          $scope.vm.myClick = function($event) {
<body ng-app="myapp">
  <div ng-controller="mainController">
    <input type="checkbox" ng-model="vm.myChkModel" ng-change="vm.myClick(vm.myChkModel)">

what is the use of Eval() in

While binding a databound control, you can evaluate a field of the row in your data source with eval() function.

For example you can add a column to your gridview like that :

<asp:BoundField DataField="YourFieldName" />

And alternatively, this is the way with eval :

        <asp:Label ID="lbl" runat="server" Text='<%# Eval("YourFieldName") %>'>

It seems a little bit complex, but it's flexible, because you can set any property of the control with the eval() function :

        <asp:HyperLink ID="HyperLink1" runat="server" 
          NavigateUrl='<%# "ShowDetails.aspx?id="+Eval("Id") %>' 
          Text='<%# Eval("Text", "{0}") %>'></asp:HyperLink>

Passing a string with spaces as a function argument in bash

Another solution to the issue above is to set each string to a variable, call the function with variables denoted by a literal dollar sign \$. Then in the function use eval to read the variable and output as expected.


  eval string1="$1"
  eval string2="$2"
  eval string3="$3"

  echo "string1 = ${string1}"
  echo "string2 = ${string2}"
  echo "string3 = ${string3}"

var2="second string with spaces"

myFunction "\${var1}" "\${var2}" "\${var3}"

exit 0

Output is then:

    string1 = firstString
    string2 = second string with spaces
    string3 = thirdString

In trying to solve a similar problem to this, I was running into the issue of UNIX thinking my variables were space delimeted. I was trying to pass a pipe delimited string to a function using awk to set a series of variables later used to create a report. I initially tried the solution posted by ghostdog74 but could not get it to work as not all of my parameters were being passed in quotes. After adding double-quotes to each parameter it then began to function as expected.

Below is the before state of my code and fully functioning after state.

Before - Non Functioning Code


# Setup Function To Extract Each Field For The Error Report

  # Retrieves Column ${fieldNumber} From The Pipe Delimited ${detailedString} 
  #   And Strips Leading And Trailing Spaces
  echo ${detailedString} | awk -F '|' -v VAR=${fieldNumber} '{ print $VAR }' | sed 's/^[ \t]*//;s/[ \t]*$//'

while read LINE

  # Below Does Not Work Since There Are Not Quotes Around The 3
  iputId=$(getField "${var1}" 3)

exit 0

After - Functioning Code


# Setup Function To Extract Each Field For The Report

  # Retrieves Column ${fieldNumber} From The Pipe Delimited ${detailedString} 
  #   And Strips Leading And Trailing Spaces
  echo ${detailedString} | awk -F '|' -v VAR=${fieldNumber} '{ print $VAR }' | sed 's/^[ \t]*//;s/[ \t]*$//'

while read LINE

  # Below Now Works As There Are Quotes Around The 3
  iputId=$(getField "${var1}" "3")

exit 0

Delete all data in SQL Server database

  1. First you'll have to disable all the triggers :

    sp_msforeachtable 'ALTER TABLE ? DISABLE TRIGGER all';
  2. Run this script : (Taken from this post Thank you @SQLMenace)

    SELECT 'USE [' + db_name() +']';
    ;WITH a AS 
         SELECT 0 AS lvl, 
                t.object_id AS tblID 
         FROM sys.TABLES t
         WHERE t.is_ms_shipped = 0
           AND t.object_id NOT IN (SELECT f.referenced_object_id 
                                   FROM sys.foreign_keys f)
         UNION ALL
         SELECT a.lvl + 1 AS lvl, 
                f.referenced_object_id AS tblId
         FROM a
         INNER JOIN sys.foreign_keys f ON a.tblId = f.parent_object_id 
                                       AND a.tblID <> f.referenced_object_id
        'Delete from ['+ object_schema_name(tblID) + '].[' + object_name(tblId) + ']' 
    FROM a
    GROUP BY tblId 
    ORDER BY MAX(lvl),1

This script will produce DELETE statements in proper order. starting from referenced tables then referencing ones

  1. Copy the DELETE FROM statements and run them once

  2. enable triggers

    sp_msforeachtable 'ALTER TABLE ? ENABLE TRIGGER all'
  3. Commit the changes :

    begin transaction

What is the difference between java and core java?

Core Java:
It’s a general term used by Sun Microsystems to describe the standard version of Java (JSE). It’s the most basic version of Java which sets the foundation for all other editions of Java plus a set of related technologies such as CORBA, Java VM, etc. Core Java refers to a collection of libraries rather than just the programming language.

Java :
Java is hypothetically everywhere, thanks to its readability and simplicity. From mobile applications to websites, game consoles to datacenters, from mobile phones to the Internet, Java is everywhere. Millions of devices throughout the world use Java as a core programming language. Even all native Android apps come built-in with Java and several companies use Java as server-side scripting language for backend development.

Batchfile to create backup and rename with timestamp

Yes, to make it run in the background create a shortcut to the batch file and go into the properties. I'm on a Linux machine ATM but I believe the option you are wanting is in the advanced tab.

You can also run your batch script through a vbs script like this:

CreateObject("Wscript.Shell").Run "your_batch_file.bat", 0, True

This will execute your batch file with no cmd window shown.

struct.error: unpack requires a string argument of length 4

The struct module mimics C structures. It takes more CPU cycles for a processor to read a 16-bit word on an odd address or a 32-bit dword on an address not divisible by 4, so structures add "pad bytes" to make structure members fall on natural boundaries. Consider:

struct {                   11
    char a;      012345678901
    short b;     ------------
    char c;      axbbcxxxdddd
    int d;

This structure will occupy 12 bytes of memory (x being pad bytes).

Python works similarly (see the struct documentation):

>>> import struct
>>> struct.pack('BHBL',1,2,3,4)
>>> struct.calcsize('BHBL')

Compilers usually have a way of eliminating padding. In Python, any of =<>! will eliminate padding:

>>> struct.calcsize('=BHBL')
>>> struct.pack('=BHBL',1,2,3,4)

Beware of letting struct handle padding. In C, these structures:

struct A {       struct B {
    short a;         int a;
    char b;          char b;
};               };

are typically 4 and 8 bytes, respectively. The padding occurs at the end of the structure in case the structures are used in an array. This keeps the 'a' members aligned on correct boundaries for structures later in the array. Python's struct module does not pad at the end:

>>> struct.pack('LB',1,2)
>>> struct.pack('LBLB',1,2,3,4)

Media Queries - In between two widths

You need to switch your values:

/* No greater than 900px, no less than 400px */
@media (max-width:900px) and (min-width:400px) {
    .foo {

Demo: (using background color, so it's easier to confirm)

Why can I not switch branches?

you can reset your branch with HEAD

git reset --hard branch_name

then fetch branches and delete branches which are not on remote from local,

git fetch -p 

How to use aria-expanded="true" to change a css property

Why javascript when you can use just css?

  background-color: #42DCA3;_x000D_
<li class="active">_x000D_
   <a href="#3a" class="btn btn-default btn-lg" data-toggle="tab" aria-expanded="true"> _x000D_
       <span class="network-name">Google+</span>_x000D_
<li class="active">_x000D_
   <a href="#3a" class="btn btn-default btn-lg" data-toggle="tab" aria-expanded="false"> _x000D_
       <span class="network-name">Google+</span>_x000D_

How to git-cherry-pick only changes to certain files?

The other methods didn't work for me since the commit had a lot of changes and conflicts to a lot of other files. What I came up with was simply

git show SHA -- file1.txt file2.txt | git apply -

It doesn't actually add the files or do a commit for you so you may need to follow it up with

git add file1.txt file2.txt
git commit -c SHA

Or if you want to skip the add you can use the --cached argument to git apply

git show SHA -- file1.txt file2.txt | git apply --cached -

You can also do the same thing for entire directories

git show SHA -- dir1 dir2 | git apply -

DB2 Query to retrieve all table names for a given schema

select name from sysibm.systables 
where name like '%ISP%' 
and type = 'T'

Necessary to add link tag for favicon.ico?

To choose a different location or file type (e.g. PNG or SVG) for the favicon:
One reason can be that you want to have the icon in a specific location, perhaps in the images folder or something alike. For example:

<link rel="icon" href="_/img/favicon.png">

This diferent location may even be a CDN, just like SO seems to do with <link rel="shortcut icon" href="">.

To learn more about using other file types like PNG check out this question.

For cache busting purposes:
Add a query string to the path for cache-busting purposes:

<link rel="icon" href="/favicon.ico?v=1.1"> 

Favicons are very heavily cached and this a great way to ensure a refresh.

Footnote about default location:
As far as the first bit of the question: all modern browsers would detect a favicon at the default location, so that's not a reason to use a link for it.

Footnote about rel="icon":
As indicated by @Semanino's answer, using rel="shortcut icon" is an old technique which was required by older versions of Internet Explorer, but in most cases can be replaced by the more correct rel="icon" instruction. The article @Semanino based this on properly links to the appropriate spec which shows a rel value of shortcut isn't a valid option.

How to sign an android apk file

APK Signing Process

To manually sign an Android APK file run these three commands:

  1. Generate Keystore file

    keytool -genkey -v -keystore YOUR_KEYSTORE_NAME.keystore -alias ALIAS_NAME -keyalg RSA -keysize 2048 -validity 10000
  2. Sign Your APK file using jarsigner

    jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore KEYSTORE_FILE_PATH UNSIGNED_APK_PATH ALIAS_NAME
  3. Align Signed APK using zipalign tool



Generate Keystore file

keytool -genkey -v -keystore YOUR_KEYSTORE_NAME.keystore -alias ALIAS_NAME -keyalg RSA -keysize 2048 -validity 10000


keytool -genkey -v -keystore id.keystore -alias MySignedApp -keyalg RSA -keysize 2048 -validity 10000

keystore password : yourApp@123 key password : yourApp@123


D:\ru\SignedBuilds\MySignedApp>keytool -genkey -v -keystore id.keystore
 -alias MySignedApp -keyalg RSA -keysize 2048 -validity 10000
Enter keystore password:
Re-enter new password:
What is your first and last name?
  [Unknown]:  MySignedApp Sample
What is the name of your organizational unit?
  [Unknown]:  Information Technology
What is the name of your organization?
  [Unknown]:  MySignedApp Demo
What is the name of your City or Locality?
  [Unknown]:  Mumbai
What is the name of your State or Province?
  [Unknown]:  Maharashtra
What is the two-letter country code for this unit?
  [Unknown]:  IN
Is CN=MySignedApp Demo, OU=Information Technology, O=MySignedApp Demo, L=Mumbai, ST=Maharashtra, C=IN corr
  [no]:  y

Generating 2,048 bit RSA key pair and self-signed certificate (SHA256withRSA) with a validity of 10,
000 days
        for: CN=MySignedApp Demo, OU=Information Technology, O=MySignedApp Demo, L=Mumbai, ST=Maharashtra,
Enter key password for <MySignedApp>
        (RETURN if same as keystore password):
Re-enter new password:
[Storing id.keystore]



Sign your app with your private keystore using jarsigner

jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore KEYSTORE_FILE_PATH UNSIGNED_APK_PATH ALIAS_NAME


jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore D:\ru\SignedBuilds\MySignedApp\id.keystore D:\ru\SignedBuilds\MySignedApp\MySignedAppS1-release-unsigned.apk id


D:\ru\SignedBuilds\MySignedApp>jarsigner -verbose -sigalg SHA1withRSA -
digestalg SHA1 -keystore D:\ru\SignedBuilds\MySignedApp\id.keystore D:\ru\SignedBuilds\MySignedApp\MySignedAppS1-release-unsigned.apk id ---
Enter Passphrase for keystore:
   adding: META-INF/---.SF
   adding: META-INF/---.RSA
  signing: AndroidManifest.xml
    signing: classes.dex
  signing: lib/commons-codec-1.6.jar
  signing: lib/armeabi/
jar signed.

No -tsa or -tsacert is provided and this jar is not timestamped. Without a timestamp, users may not
be able to validate this jar after the signer certificate's expiration date (2044-02-07) or after an
y future revocation date.


Verify that your APK is signed

jarsigner -verify -verbose -certs JARSIGNED_APK_FILE_PATH


jarsigner -verify -verbose -certs MySignedAppS1-release-unsigned.apk


D:\ru\SignedBuilds\MySignedApp>jarsigner -verify -verbose -certs MySignedAppS1-release-unsigned.apk
 s = signature was verified
  m = entry is listed in manifest
  k = at least one certificate was found in keystore
  i = at least one certificate was found in identity scope

jar verified.

This jar contains entries whose certificate chain is not validated.
This jar contains signatures that does not include a timestamp. Without a timestamp, users may not b
e able to validate this jar after the signer certificate's expiration date (2044-02-09) or after any
 future revocation date.



Align the final APK package using zipalign



zipalign -v 4 D:\ru\SignedBuilds\MySignedApp\MySignedAppS1-release-unsigned.apk D:\ru\SignedBuilds\MySignedApp\MySignedApp.apk


D:\Android\android-sdk\build-tools\19.1.0>zipalign -v 4 D:\ru\ru_doc\Signed_apk\MySignedApp\28.09.16
_prod_playstore\MySignedAppS1-release-unsigned.apk D:\ru\ru_doc\Signed_apk\MySignedApp\28.09.16_prod
Verifying alignment of D:\ru\SignedBuilds\MySignedApp\MySignedApp.apk (

  4528613 classes.dex (OK - compressed)
 5656594 lib/commons-codec-1.6.jar (OK - compressed)
 5841869 lib/armeabi/ (OK - compressed)
Verification succesful


Verify that your APK is Aligned successfully

zipalign -c -v 4 YOUR_APK_PATH


zipalign -c -v 4 D:\ru\SignedBuilds\MySignedApp\MySignedApp.apk


D:\Android\android-sdk\build-tools\19.1.0>zipalign -c -v 4 D:\ru\SignedBuilds\MySignedApp\MySignedApp.apk
Verifying alignment of D:\ru\SignedBuilds\MySignedApp\MySignedApp.apk (

 4453984 res/drawable/zoomout.png (OK)
 4454772 res/layout/tabview.xml (OK - compressed)
 4455243 res/layout/wheel_item.xml (OK - compressed)
 4455608 resources.arsc (OK)
 4470161 classes.dex (OK - compressed)
 5597923 lib/commons-codec-1.6.jar (OK - compressed)
 5783198 lib/armeabi/ (OK - compressed)
Verification succesful



The verify command is just to check whether APK is built and signed correctly!


I hope this will help one and all :)

Setting default permissions for newly created files and sub-directories under a directory in Linux?

To get the right ownership, you can set the group setuid bit on the directory with

chmod g+rwxs dirname

This will ensure that files created in the directory are owned by the group. You should then make sure everyone runs with umask 002 or 007 or something of that nature---this is why Debian and many other linux systems are configured with per-user groups by default.

I don't know of a way to force the permissions you want if the user's umask is too strong.

C# Pass Lambda Expression as Method Parameter

Use a Func<T1, T2, TResult> delegate as the parameter type and pass it in to your Query:

public List<IJob> getJobs(Func<FullTimeJob, Student, FullTimeJob> lambda)
  using (SqlConnection connection = new SqlConnection(getConnectionString())) {
    return connection.Query<FullTimeJob, Student, FullTimeJob>(sql, 
        splitOn: "user_id",
        param: parameters).ToList<IJob>();   

You would call it:

getJobs((job, student) => {         
        job.Student = student;
        job.StudentId = student.Id;
        return job;

Or assign the lambda to a variable and pass it in.

Setting SMTP details for php mail () function

Try from your dedicated server to telnet to on port 465. It might be blocked by your internet provider

Find objects between two dates MongoDB

To clarify. What is important to know is that:

  • Yes, you have to pass a Javascript Date object.
  • Yes, it has to be ISODate friendly
  • Yes, from my experience getting this to work, you need to manipulate the date to ISO
  • Yes, working with dates is generally always a tedious process, and mongo is no exception

Here is a working snippet of code, where we do a little bit of date manipulation to ensure Mongo (here i am using mongoose module and want results for rows whose date attribute is less than (before) the date given as myDate param) can handle it correctly:

var inputDate = new Date(myDate.toISOString());
    'date': { $lte: inputDate }

What is the PostgreSQL equivalent for ISNULL()


SELECT COALESCE(NULLIF(field, ''), another_field) FROM table_name

IF function with 3 conditions

You can do it this way:

=IF(E9>21,"Text 1",IF(AND(E9>=5,E9<=21),"Test 2","Text 3"))

Note I assume you meant >= and <= here since your description skipped the values 5 and 21, but you can adjust these inequalities as needed.

Or you can do it this way:

=IF(E9>21,"Text 1",IF(E9<5,"Text 3","Text 2"))

How can I refresh or reload the JFrame?

Try this code. I also faced the same problem, but some how I solved it.

public class KitchenUserInterface {

    private JFrame frame;
    private JPanel main_panel, northpanel , southpanel;
    private JLabel label;
    private JButton nextOrder;
    private JList list;

    private static KitchenUserInterface kitchenRunner ;

    public void setList(String[] order){
        kitchenRunner= new KitchenUserInterface(order);


    public KitchenUserInterface getInstance() {
        if(kitchenRunner == null) {
            synchronized(KitchenUserInterface.class) {
                if(kitchenRunner == null) {
                    kitchenRunner = new KitchenUserInterface();

        return this.kitchenRunner;

    private KitchenUserInterface() {

        frame = new JFrame("Lullaby's Kitchen");
        main_panel = new JPanel();
        main_panel.setLayout(new BorderLayout());

        northpanel = new JPanel();
        northpanel.setLayout(new FlowLayout());

        label = new JLabel("Kitchen");


        main_panel.add(northpanel , BorderLayout.NORTH);

        frame.setSize(500 , 500 );

    private KitchenUserInterface (String[] order){
        list = new JList<String>(order);
        main_panel.add(list , BorderLayout.CENTER);

        southpanel = new JPanel();
         southpanel.setLayout(new FlowLayout());

         nextOrder = new JButton("Next Order Set");
         nextOrder.addActionListener(new OrderUpListener(list));
         main_panel.add(southpanel, BorderLayout.SOUTH);


    public static void main(String[] args) {
        KitchenUserInterface dat = kitchenRunner.getInstance();

        catch(Exception event) {
            System.out.println("Error sleep");



Is if(document.getElementById('something')!=null) identical to if(document.getElementById('something'))?

A reference to an element will never look "falsy", so leaving off the explicit null check is safe.

Javascript will treat references to some values in a boolean context as false: undefined, null, numeric zero and NaN, and empty strings. But what getElementById returns will either be an element reference, or null. Thus if the element is in the DOM, the return value will be an object reference, and all object references are true in an if () test. If the element is not in the DOM, the return value would be null, and null is always false in an if () test.

It's harmless to include the comparison, but personally I prefer to keep out bits of code that don't do anything because I figure every time my finger hits the keyboard I might be introducing a bug :)

Note that those using jQuery should not do this:

if ($('#something')) { /* ... */ }

because the jQuery function will always return something "truthy" — even if no element is found, jQuery returns an object reference. Instead:

if ($('#something').length) { /* ... */ }

edit — as to checking the value of an element, no, you can't do that at the same time as you're checking for the existence of the element itself directly with DOM methods. Again, most frameworks make that relatively simple and clean, as others have noted in their answers.

Making href (anchor tag) request POST instead of GET?

To do POST you'll need to have a form.

<form action="employee.action" method="post">
    <input type="submit" value="Employee1" />

There are some ways to post data with hyperlinks, but you'll need some javascript, and a form.

Some tricks: Make a link use POST instead of GET and How do you post data with a link

Edit: to load response on a frame you can target your form to your frame:

<form action="employee.action" method="post" target="myFrame">

How to Lock Android App's Orientation to Portrait in Phones and Landscape in Tablets?

You just have to define the property below inside the activity element in your AndroidManifest.xml file. It will restrict your orientation to portrait.



            android:screenOrientation="portrait" >

if you want this to apply to the whole app define the property below inside the application tag like so:


Additionaly, as per Eduard Luca's comment below, you can also use screenOrientation="sensorPortrait" if you want to enable rotation by 180 degrees.

Remove or uninstall library previously added : cocoapods

Remove pod name from Podfile then Open Terminal, set project folder path and Run pod update command.

NOTE: pod update will update all the libraries to the latest version and will also remove those libraries whose name have been removed from podfile.

How to properly ignore exceptions

I needed to ignore errors in multiple commands and fuckit did the trick

import fuckit

def helper():


Why Is `Export Default Const` invalid?

const is like let, it is a LexicalDeclaration (VariableStatement, Declaration) used to define an identifier in your block.

You are trying to mix this with the default keyword, which expects a HoistableDeclaration, ClassDeclaration or AssignmentExpression to follow it.

Therefore it is a SyntaxError.

If you want to const something you need to provide the identifier and not use default.

export by itself accepts a VariableStatement or Declaration to its right.

AFAIK the export in itself should not add anything to your current scope.

The following is fineexport default Tab;

Tab becomes an AssignmentExpression as it's given the name default ?

export default Tab = connect( mapState, mapDispatch )( Tabs ); is fine

Here Tab = connect( mapState, mapDispatch )( Tabs ); is an AssignmentExpression.

Why do I keep getting 'SVN: Working Copy XXXX locked; try performing 'cleanup'?

  1. Select the project
  2. Right click on the selected Project
  3. Team -> Cleanup

Problem Solved.

Note: The Above steps will work only Eclipse(Indigo package)

How to execute a .bat file from a C# windows form app?

Here is what you are looking for:

Service hangs up at WaitForExit after calling batch file

It's about a question as to why a service can't execute a file, but it shows all the code necessary to do so.

'NOT LIKE' in an SQL query

After "AND" and after "OR" the QUERY has forgotten what it is all about.

I would also not know that it is about in any SQL / programming language.

if(SOMETHING equals "X" or SOMETHING equals "Y")


Split a String into an array in Swift?

Here is an algorithm I just build, which will split a String by any Character from the array and if there is any desire to keep the substrings with splitted characters one could set the swallow parameter to true.

Xcode 7.3 - Swift 2.2:

extension String {

    func splitBy(characters: [Character], swallow: Bool = false) -> [String] {

        var substring = ""
        var array = [String]()
        var index = 0

        for character in self.characters {

            if let lastCharacter = substring.characters.last {

                // swallow same characters
                if lastCharacter == character {


                } else {

                    var shouldSplit = false

                    // check if we need to split already
                    for splitCharacter in characters {
                        // slit if the last character is from split characters or the current one
                        if character == splitCharacter || lastCharacter == splitCharacter {

                            shouldSplit = true

                    if shouldSplit {

                        substring = String(character)

                    } else /* swallow characters that do not equal any of the split characters */ {

            } else /* should be the first iteration */ {


            index += 1

            // add last substring to the array
            if index == self.characters.count {


        return array.filter {

            if swallow {

                return true

            } else {

                for splitCharacter in characters {

                    if $0.characters.contains(splitCharacter) {

                        return false
                return true


"test text".splitBy([" "]) // ["test", "text"]
"test++text--".splitBy(["+", "-"], swallow: true) // ["test", "++" "text", "--"]

Convert object to JSON in Android

As of Android 3.0 (API Level 11) Android has a more recent and improved JSON Parser.

Reads a JSON (RFC 4627) encoded value as a stream of tokens. This stream includes both literal values (strings, numbers, booleans, and nulls) as well as the begin and end delimiters of objects and arrays. The tokens are traversed in depth-first order, the same order that they appear in the JSON document. Within JSON objects, name/value pairs are represented by a single token. cannot open shared object file

Here on a openSuse 12.3 the solution was installing the 32-bit version of libaio in addition. Oracle seems to need this now, although on 12.1 it run without the 32-bit version.

How to store images in mysql database using php

insert image zh

-while we insert image in database using insert query

$Image = $_FILES['Image']['name'];
      $file_path = 'upload/';
      $file_path = $file_path . basename( $_FILES['Image']['name']);    
      if(move_uploaded_file($_FILES['Image']['tmp_name'], $file_path)) 

Excel VBA: AutoFill Multiple Cells with Formulas

Based on my Comment here is one way to get what you want done:

Start byt selecting any cell in your range and Press Ctrl + T

This will give you this pop up:

enter image description here

make sure the Where is your table text is correct and click ok you will now have:

enter image description here

Now If you add a column header in D it will automatically be added to the table all the way to the last row:

enter image description here

Now If you enter a formula into this column:

enter image description here

After you enter it, the formula will be auto filled all the way to last row:

enter image description here

Now if you add a new row at the next row under your table:

enter image description here

Once entered it will be resized to the width of your table and all columns with formulas will be added also:

enter image description here

Hope this solves your problem!

Write to custom log file from a Bash script

There's good amount of detail on logging for shell scripts via global varaibles of shell. We can emulate the similar kind of logging in shell script: The post has details on introdducing log levels like INFO , DEBUG, ERROR. Tracing details like script entry, script exit, function entry, function exit.

Sample Log: enter image description here

Inline elements shifting when made bold on hover

An alternative approach would be to "emulate" bold text via text-shadow. This has the bonus (/malus, depending on your case) to work also on font icons.

   nav li a:hover {
      text-decoration: none;
      text-shadow: 0 0 1px; /* "bold" */

Kinda hacky, although it saves you from duplicating text (which is useful if it is a lot, as it was in my case).

How do you implement a re-try-catch?

Most of these answers are essentially the same. Mine is also, but this is the form I like

boolean completed = false;
Throwable lastException = null;
for (int tryCount=0; tryCount < config.MAX_SOME_OPERATION_RETRIES; tryCount++)
    try {
        completed = some_operation();
    catch (UnlikelyException e) {
        lastException = e;
if (!completed) {

How correctly produce JSON by RESTful web service?

You could use a package like org.json

Because you will need to use JSONObjects more often.

There you can easily create JSONObjects and put some values in it:

 JSONObject json = new JSONObject();
 JSONArray array=new JSONArray();
    json.put("friends", array);


    {"friends": [

edit This has the advantage that you can build your responses in different layers and return them as an object

Android device chooser - My device seems offline

I have HTC wildfire and disabling and enabling the debugging worked fine for the "offline" problem. The error does not show up.

However I ran into a new problem when trying to import a python file with sl3a : "no moduled named android" explained here. That being said, I still cannot run this file located somewhere on the SD Card/python folder. I can connect with androidscreencast.jnlp and it works fine :)

How to return multiple values?

You can only return one value, but it can be an object that has multiple fields - ie a "value object". Eg

public class MyResult {
    int returnCode;
    String errorMessage;
    // etc

public MyResult someMethod() {
    // impl here

java.util.Date format SSSSSS: if not microseconds what are the last 3 digits?

Use java.sql.Timestamp.toString if you want to get fractional seconds in text representation. The difference betwen Timestamp from DB and Java Date is that DB precision is nanoseconds while Java Date precision is milliseconds.

How to force child div to be 100% of parent div's height without specifying parent's height?

#main {
   display: table;
#navigation, #content {
   display: table-cell;

Look at this example.

In Python, how do I split a string and keep the separators?

  1. replace all seperator: (\W) with seperator + new_seperator: (\W;)

  2. split by the new_seperator: (;)

def split_and_keep(seperator, s):
  return re.split(';', re.sub(seperator, lambda match: + ';', s))

print('\W', 'foo/bar spam\neggs')

How to improve performance of ngRepeat over a huge dataset (angular.js)?

Sometimes what happened,you get the data from server (or back-end) in few ms (for example I'm I am assuming it 100ms) but it takes more time to display in our web page (let's say it is taking 900ms to display).

So, What is happening here is 800ms It is taking just to render web page.

What I have done in my web application is, I have used pagination (or you can use infinite scrolling also) to display list of data. Let's say I am showing 50 data/page.

So I will not load render all the data at once,only 50 data I am loading initially which takes only 50ms (I'm assuming here).

so total time here decreased from 900ms to 150ms, once user request next page then display next 50 data and so on.

Hope this will help you to improve the performance. All the best

pandas dataframe convert column type to string or categorical

Prior answers focused on nominal data (e.g. unordered). If there is a reason to impose order for an ordinal variable, then one would use:

# Transform to category
df['zipcode_category'] = df['zipcode_category'].astype('category')

# Add ordered category
df['zipcode_ordered'] = df['zipcode_category']

# Setup the ordering
    new_categories = [90211, 90210], ordered = True, inplace = True

# Output IDs
df['zipcode_ordered_id'] =
#  zipcode_category zipcode_ordered  zipcode_ordered_id
#            90210           90210                   1
#            90211           90211                   0

More details on setting ordered categories can be found at the pandas website:

How can I run Android emulator for Intel x86 Atom without hardware acceleration on Windows 8 for API 21 and 19?

I have a pc with intel c2d without hardware accelaration i am having same problem in android studio. firstly i get bored with android studio and installed eclipse+sdk+adt then i have installed every thing and started emulator it worked then the same emulator worked in android studio for direct launching application in android studio and i have also runned the sample app that emulator so you can run android studio without virtualization technique even your processor does not sopport vt-x

How to append multiple values to a list in Python

Other than the append function, if by "multiple values" you mean another list, you can simply concatenate them like so.

>>> a = [1,2,3]
>>> b = [4,5,6]
>>> a + b
[1, 2, 3, 4, 5, 6]

Concatenating strings in Razor

You can use:

@foreach (var item in Model)
  @Html.DisplayFor(modelItem => item.address + " " + 

Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript?

I've occasionally found the following idiom useful:


can be rewritten as:


This takes advantage of the fact that getting unknown attributes on an object returns undefined, rather than throwing an exception as it does on null or undefined, so we replace null and undefined with an empty object before navigating.

Does Android keep the .apk files? if so where?

There is no standard location, however you can use the PackageManager to find out about packages and the ApplicationInfo class you can get from there has various information about a particular package: the path to its .apk, the path to its data directory, the path to a resource-only .apk (for forward locked apps), etc. Note that you may or may not have permission to read these directories depending on your relationship with the other app; however, all apps are able to read the resource .apk (which is also the real .apk for non-forward-locked app).

If you are just poking around in the shell, currently non-forward-locked apps are located in /data/app/.apk. The shell user can read a specific .apk, though it can't list the directory. In a future release the naming convention will be changed slightly, so don't count on it remaining the same, but if you get the path of the .apk from the package manager then you can use it in the shell.

How do I get an object's unqualified (short) class name?

The fastest and imho easiest solution that works in any environment is:


namespace \My\Awesome\Namespace;

class Foo {

  private $shortName;

  public function fastShortName() {
    if ($this->shortName === null) {
      $this->shortName = explode("\\", static::class);
      $this->shortName = end($this->shortName);
    return $this->shortName;

  public function shortName() {
    return basename(strtr(static::class, "\\", "/"));


echo (new Foo())->shortName(); // "Foo"


How to select the rows with maximum values in each group with dplyr?

You can use top_n

df %>% group_by(A, B) %>% top_n(n=1)

This will rank by the last column (value) and return the top n=1 rows.

Currently, you can't change the this default without causing an error (See

Java - Find shortest path between 2 points in a distance weighted map

Estimated sanjan:

The idea behind Dijkstra's Algorithm is to explore all the nodes of the graph in an ordered way. The algorithm stores a priority queue where the nodes are ordered according to the cost from the start, and in each iteration of the algorithm the following operations are performed:

  1. Extract from the queue the node with the lowest cost from the start, N
  2. Obtain its neighbors (N') and their associated cost, which is cost(N) + cost(N, N')
  3. Insert in queue the neighbor nodes N', with the priority given by their cost

It's true that the algorithm calculates the cost of the path between the start (A in your case) and all the rest of the nodes, but you can stop the exploration of the algorithm when it reaches the goal (Z in your example). At this point you know the cost between A and Z, and the path connecting them.

I recommend you to use a library which implements this algorithm instead of coding your own. In Java, you might take a look to the Hipster library, which has a very friendly way to generate the graph and start using the search algorithms.

Here you have an example of how to define the graph and start using Dijstra with Hipster.

// Create a simple weighted directed graph with Hipster where
// vertices are Strings and edge values are just doubles
HipsterDirectedGraph<String,Double> graph = GraphBuilder.create()

// Create the search problem. For graph problems, just use
// the GraphSearchProblem util class to generate the problem with ease.
SearchProblem p = GraphSearchProblem

// Search the shortest path from "A" to "F"

You only have to substitute the definition of the graph for your own, and then instantiate the algorithm as in the example.

I hope this helps!

What is the difference between precision and scale?

Precision is the total number of digits, can be between 1 and 38.
Scale is the number of digits after the decimal point, may also be set as negative for rounding.

NUMBER(7,5): 12.12345
NUMBER(5,0): 12345

More details on the ORACLE website:

Page vs Window in WPF?

Pages are intended for use in Navigation applications (usually with Back and Forward buttons, e.g. Internet Explorer). Pages must be hosted in a NavigationWindow or a Frame

Windows are just normal WPF application Windows, but can host Pages via a Frame container

How to set standard encoding in Visual Studio


It is possible with EditorConfig.

EditorConfig helps developers define and maintain consistent coding styles between different editors and IDEs.

This also includes file encoding.

EditorConfig is built-in Visual Studio 2017 by default, and I there were plugins available for versions as old as VS2012. Read more from EditorConfig Visual Studio Plugin page.


You can set up a EditorConfig configuration file high enough in your folder structure to span all your intended repos (up to your drive root should your files be really scattered everywhere) and configure the setting charset:

charset: set to latin1, utf-8, utf-8-bom, utf-16be or utf-16le to control the character set.

You can add filters and exceptions etc on every folder level or by file name/type should you wish for finer control.

Once configured then compatible IDEs should automatically do it's thing to make matching files comform to set rules. Note that Visual Studio does not automatically convert all your files but do its bit when you work with files in IDE (open and save).

What next

While you could have a Visual-studio-wide setup, I strongly suggest to still include an EditorConfig root to your solution version control, so that explicit settings are automatically synced to all team members as well. Your drive root editorconfig file can be the fallback should some project not have their own editorconfig files set up yet.

Finding even or odd ID values

For finding the even number we should use

select num from table where ( num % 2 ) = 0

Difference in System. exit(0) , System.exit(-1), System.exit(1 ) in Java

System.exit(0) by convention, a zero status code indicates successful termination.

System.exit(1) -It means termination unsuccessful due to some error

Change Circle color of radio button

just use android:buttonTint="@color/colorPrimary" attribute on tag, hope it will help

How To Set Text In An EditText

String string="this is a text";

I have found String to be a useful Indirect Subclass of CharSequence find setText(CharSequence text)

What happens to C# Dictionary<int, int> lookup if the key does not exist?

If you're just checking before trying to add a new value, use the ContainsKey method:

if (!openWith.ContainsKey("ht"))
    openWith.Add("ht", "hypertrm.exe");

If you're checking that the value exists, use the TryGetValue method as described in Jon Skeet's answer.

linux shell script: split string, put them in an array then loop through them

while [ -n "${a}" ]
    echo ${a%%;*}

How do you use https / SSL on localhost?

It is easy to create a self-signed certificate, import it, and bind it to your website.

1.) Create a self-signed certificate:

Run the following 4 commands, one at a time, from an elevated Command Prompt:

cd C:\Program Files (x86)\Windows Kits\8.1\bin\x64

makecert -r -n "CN=localhost" -b 01/01/2000 -e 01/01/2099 -eku -sv localhost.pvk localhost.cer

cert2spc localhost.cer localhost.spc

pvk2pfx -pvk localhost.pvk -spc localhost.spc -pfx localhost.pfx

2.) Import certificate to Trusted Root Certification Authorities store:

start --> run --> mmc.exe --> Certificates plugin --> "Trusted Root Certification Authorities" --> Certificates

Right-click Certificates --> All Tasks --> Import Find your "localhost" Certificate at C:\Program Files (x86)\Windows Kits\8.1\bin\x64\

3.) Bind certificate to website:

start --> (IIS) Manager --> Click on your Server --> Click on Sites --> Click on your top level site --> Bindings

Add or edit a binding for https and select the SSL certificate called "localhost".

4.) Import Certificate to Chrome:

Chrome Settings --> Manage Certificates --> Import .pfx certificate from C:\certificates\ folder

Test Certificate by opening Chrome and navigating to https://localhost/

Basic http file downloading and saving to disk in python?

Exotic Windows Solution

import subprocess"powershell Invoke-WebRequest {} -OutFile {}".format(your_url, filename), shell=True)

Position buttons next to each other in the center of page

Utilize regular buttons and set the display property to inline in order to center the buttons on a single line. Setting the display property to inline-block will also put them on the same line, but they will not be centered via that display property setting.

Can't push to GitHub because of large file which I already deleted

The solution to keep the large files/folders within the working folder

This is the line that worked to solve the problem asked here (from answer 1):

git filter-branch --index-filter 'git rm -r --cached --ignore-unmatch <file/dir>' HEAD

This command also delete the file/dir if the file/dir is within the working tree.

If you want to keep the file/folder within the working tree I propose taking the following steps.

  1. After that error run git reset HEAD^
  2. Add the file/folder in question into ``.gitignore``` file.

  3. Proceed as usual git add . which might capture other files/folders but must capture .gitignore file. Next is git commit -m"message" and finally git push origin <branch_name>

m2e lifecycle-mapping not found

You can use this dummy plugin:

mvn archetype:generate -DgroupId=org.eclipse.m2e -DartifactId=lifecycle-mapping -Dversion=1.0.0 -DarchetypeArtifactId=maven-archetype-mojo

After generating the project install/deploy it.

Why is the apt-get function not working in the terminal on Mac OS X v10.9 (Mavericks)?

As Homebrew is my favorite for macOS although it is possible to have apt-get on macOS using Fink.

Adb Devices can't find my phone

I have a Fascinate as well, and had to change the phone's USB communication mode from MODEM to PDA. Use:

  • enter **USBUI (**87284)

to change both USB and UART to PDA mode. I also had to disconnect and reconnect the USB cable. Once Windows re-recognized the device again, "adb devices" started returning my device.

BTW if you use CDMA workshop or the equivalent, you will need to switch the setting back to MODEM.

vim line numbers - how to have them on by default?

in home directory you will find a file called ".vimrc" in that file add this code "set nu" and save and exit and open new vi file and you will find line numbers on that.

How do I make a redirect in PHP?

Here are my thoughts:

IMHO, the best way to redirect an incoming request would be by using location headers, which goes

    header("Location: /index.php");

Once this statement is executed, and output sent out, the browser will begin re-directing the user. However, ensure that there hasn't been any output (any echo / var_dump) before sending headers, else it will lead to errors.

Although this is a quick-and-dirty way to achieve what was originally asked, it would eventually turn out to be an SEO disaster, as this kind of redirect is always interpreted as a 301 / 302 redirect, hence search engines will always see your index page as a re-directed page, and not something of a landing page / main page.

Hence it will affect the SEO settings of the website.

Delete commit on gitlab

We've had similar problem and it was not enough to only remove commit and force push to GitLab.
It was still available in GitLab interface using url:<group>/<project>/commit/<commit hash>

We've had to remove project from GitLab and recreate it to get rid of this commit in GitLab UI.

How can I find out what FOREIGN KEY constraint references a table in SQL Server?

In Object Explorer, expand the table, and expand the Keys:

enter image description here

Fastest way to check if a file exist using standard C++/C++11/C?

You may also do bool b = std::ifstream('filename').good();. Without the branch instructions(like if) it must perform faster as it needs to be called thousands of times.

Check whether a string contains a substring

Another possibility is to use regular expressions which is what Perl is famous for:

if ($mystring =~ /s1\.domain\.com/) {
   print qq("$mystring" contains ""\n);

The backslashes are needed because a . can match any character. You can get around this by using the \Q and \E operators.

my $substring = "";
    if ($mystring =~ /\Q$substring\E/) {
   print qq("$mystring" contains "$substring"\n);

Or, you can do as eugene y stated and use the index function. Just a word of warning: Index returns a -1 when it can't find a match instead of an undef or 0.

Thus, this is an error:

my $substring = "";
if (not index($mystring, $substr)) {
    print qq("$mystring" doesn't contains "$substring"\n";

This will be wrong if is at the beginning of your string. I've personally been burned on this more than once.

SQL Query - Using Order By in UNION

The second table cannot include the table name in the ORDER BY clause.


SELECT table1.field1 FROM table1 ORDER BY table1.field1
SELECT table2.field1 FROM table2 ORDER BY field1

Does not throw an exception

Simple URL GET/POST function in Python


Here's a few common ways to use it:

import requests
url = 'https://...'
payload = {'key1': 'value1', 'key2': 'value2'}

r = requests.get(url)

# GET with params in URL
r = requests.get(url, params=payload)

# POST with form-encoded data
r =, data=payload)

# POST with JSON 
import json
r =, data=json.dumps(payload))

# Response, status etc


>>> from httplib2 import Http
>>> from urllib import urlencode
>>> h = Http()
>>> data = dict(name="Joe", comment="A test comment")
>>> resp, content = h.request("", "POST", urlencode(data))
>>> resp
{'status': '200', 'transfer-encoding': 'chunked', 'vary': 'Accept-Encoding,User-Agent',
 'server': 'Apache', 'connection': 'close', 'date': 'Tue, 31 Jul 2007 15:29:52 GMT', 
 'content-type': 'text/html'}

Meaning of Open hashing and Closed hashing

The name open addressing refers to the fact that the location ("address") of the element is not determined by its hash value. (This method is also called closed hashing).

In separate chaining, each bucket is independent, and has some sort of ADT (list, binary search trees, etc) of entries with the same index. In a good hash table, each bucket has zero or one entries, because we need operations of order O(1) for insert, search, etc.

This is a example of separate chaining using C++ with a simple hash function using mod operator (clearly, a bad hash function)

Use PHP to convert PNG to JPG with compression?

I know it's not an exact answer to the OP, but as answers have already be given...

Do you really need to do this in PHP ?
What I mean is : if you need to convert a lot of images, doing it in PHP might not be the best way : you'll be confronted to memory_limit, max_execution_time, ...

I would also say GD might not get you the best quality/size ratio ; but not sure about that (if you do a comparison between GD and other solutions, I am very interested by the results ;-) )

Another approach, not using PHP, would be to use Image Magick via the command line (and not as a PHP extension like other people suggested)

You'd have to write a shell-script that goes through all .png files, and gives them to either

  • convert to create a new .jpg file for each .png file
  • or mogrify to directly work on the original file and override it.

As a sidenote : if you are doing this directly on your production server, you could put some sleep time between bunches of conversions, to let it cool down a bit sometimes ^^

I've use the shell script + convert/mogrify a few times (having them run for something like 10 hours one time), and they do the job really well :-)

Should I put #! (shebang) in Python scripts, and what form should it take?

Should I put the shebang in my Python scripts?

Put a shebang into a Python script to indicate:

  • this module can be run as a script
  • whether it can be run only on python2, python3 or is it Python 2/3 compatible
  • on POSIX, it is necessary if you want to run the script directly without invoking python executable explicitly

Are these equally portable? Which form is used most?

If you write a shebang manually then always use #!/usr/bin/env python unless you have a specific reason not to use it. This form is understood even on Windows (Python launcher).

Note: installed scripts should use a specific python executable e.g., /usr/bin/python or /home/me/.virtualenvs/project/bin/python. It is bad if some tool breaks if you activate a virtualenv in your shell. Luckily, the correct shebang is created automatically in most cases by setuptools or your distribution package tools (on Windows, setuptools can generate wrapper .exe scripts automatically).

In other words, if the script is in a source checkout then you will probably see #!/usr/bin/env python. If it is installed then the shebang is a path to a specific python executable such as #!/usr/local/bin/python (NOTE: you should not write the paths from the latter category manually).

To choose whether you should use python, python2, or python3 in the shebang, see PEP 394 - The "python" Command on Unix-Like Systems:

  • ... python should be used in the shebang line only for scripts that are source compatible with both Python 2 and 3.

  • in preparation for an eventual change in the default version of Python, Python 2 only scripts should either be updated to be source compatible with Python 3 or else to use python2 in the shebang line.

Counting Line Numbers in Eclipse

A very simple plugin for counting actual lines of source code is step counter eclipse plugin. Please download and try.

github link

Place the downloaded jar file under eclipse\plugin folder and restart eclipse.

Rightclick and select step counter enter image description here

Step Result enter image description here