Programs & Examples On #Nhibernate 3

Use this tag for Nhibernate version 3.x series specific question.

What's the difference between ViewData and ViewBag?

public ActionResult Index()
    ViewBag.Name = "Monjurul Habib";
    return View();

public ActionResult Index()
    ViewData["Name"] = "Monjurul Habib";
    return View();

In View:


Python: How to check a string for substrings from a list?

Try this test:

any(substring in string for substring in substring_list)

It will return True if any of the substrings in substring_list is contained in string.

Note that there is a Python analogue of Marc Gravell's answer in the linked question:

from itertools import imap
any(imap(string.__contains__, substring_list)) 

In Python 3, you can use map directly instead:

any(map(string.__contains__, substring_list))

Probably the above version using a generator expression is more clear though.

Error : Program type already present:$Behavior

Adding this to project's fixed it for us:


SSRS chart does not show all labels on Horizontal axis

Really late reply for me, but I just suffered the pain of this problem as well.

What fixed it for me (after trying the Axis label settings and intervals from those screens, none of which worked!) was select the Horizontal Axis, then when you can see all the properties find Labels, and change LabelInterval to 1.

For some reason when I set this from the pop up properties screens it either never 'stuck' or it changes a slightly different value that didn't fix my issue.

How to install Python MySQLdb module using pip?

The above answer is great, but there may be some problems when we using pip to install MySQL-python in Windows

for example,It needs some files that are associated with Visual Stdio .One solution is installing VS2008 or 2010……Obviously,it cost too much.

Another way is the answer of @bob90937 . I am here to do something to add.

with, u can download many Windows binaries of many scientific open-source extension packages for the official CPython distribution of the Python programming language.

Back to topic,we can choose the MySQL-python(py2) or Mysqlclient(py3) and use pip install to install. it gives us Great convenience!

What does string::npos mean in this code?

An answer for these days of C++17, when we have std::optional:

If you squint a bit and pretend std::string::find() returns an std::optional<std::string::size_type> (which it sort of should...) - then the condition becomes:

auto position = str.find(str2);

if ( position.has_value() ) {
    std::cout << "first 'needle' found at: " << found.value() << std::endl;

Auto highlight text in a textbox control

In window form c#. If you use Enter event it will not work. try to use MouseUp event

    bool FlagEntered;
    private void textBox1_MouseUp(object sender, MouseEventArgs e)
        if ((sender as TextBox).SelectedText == "" && !FlagEntered)
            (sender as TextBox).SelectAll();
            FlagEntered = true;

    private void textBox1_Leave(object sender, EventArgs e)
        FlagEntered = false;

What are intent-filters in Android?

Keep the first intent filter with keys MAIN and LAUNCHER and add another as ANY_NAME and DEFAULT.

Your LAUNCHER will be activity A and DEFAULT will be your activity B.

How to ensure a <select> form field is submitted when it is disabled?

I`ve been looking for a solution for this, and since i didnt find a solution in this thread i did my own.

// With jQuery
$('#selectbox').focus(function(e) {

Simple, you just blur the field when you focus on it, something like disabling it, but you actually send its data.

How to get the parents of a Python class?

If you want all the ancestors rather than just the immediate ones, use inspect.getmro:

import inspect
print inspect.getmro(cls)

Usefully, this gives you all ancestor classes in the "method resolution order" -- i.e. the order in which the ancestors will be checked when resolving a method (or, actually, any other attribute -- methods and other attributes live in the same namespace in Python, after all;-).

PHP-FPM and Nginx: 502 Bad Gateway

For anyone else struggling to get to the bottom of this, I tried adjusting timeouts as suggested as I didn't want to stop using Unix sockets...after lots of troubleshooting and not much to go on I found that this issue was being caused by the APC extension that I'd enabled in php-fpm a few months back. Disabling this extension resolved the intermittent 502 errors, easiest way to do this was by commenting out the following line :

;extension =

This did the trick for me!

How to convert image file data in a byte array to a Bitmap?

The answer of Uttam didnt work for me. I just got null when I do:

Bitmap bitmap = BitmapFactory.decodeByteArray(bitmapdata, 0, bitmapdata.length);

In my case, bitmapdata only has the buffer of the pixels, so it is imposible for the function decodeByteArray to guess which the width, the height and the color bits use. So I tried this and it worked:

//Create bitmap with width, height, and 4 bytes color (RGBA)    
Bitmap bmp = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ARGB_8888);
ByteBuffer buffer = ByteBuffer.wrap(bitmapdata);

Check for different color options

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

package lecture3;

import java.util.Scanner;

public class divisibleBy2and5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println("Enter an integer number:");
        Scanner input = new Scanner(;
        int x;
        x = input.nextInt();
         if (x % 2==0){
             System.out.println("The integer number you entered is divisible by 2");
             System.out.println("The integer number you entered is not divisible by 2");
             if(x % 5==0){
                 System.out.println("The integer number you entered is divisible by 5");
                 System.out.println("The interger number you entered is not divisible by 5");


Why doesn't document.addEventListener('load', function) work in a greasemonkey script?

To get the value of my drop down box on page load, I use


Hope this helps some one.

How can I find the length of a number?

A way for integers without banal converting to string:

var num = 9999999999; // your number
var length = 1;
while (num >= 10) {
   num /= 10;

Update Multiple Rows in Entity Framework from a list of ids

something like below

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


you can update multiple fields as below

friends.ForEach(a =>
                         a.property1 = value1;
                         a.property2 = value2;

Stupid error: Failed to load resource: net::ERR_CACHE_MISS

We get err_cache_miss error while using the bowser. Its mean there may be a problem with your browser. It due the items in the cache may be unusable or some configurations are not configured correctly. You may get the solution to clear browser data or Check browser extensions and remove extensions which you felt cause the problem or Resetting your browser or Update your browser or Disabling cache system. These are some tricks to come out this error.

Select SQL results grouped by weeks

Declare @DatePeriod datetime
Set @DatePeriod = '2011-05-30'

Select  ProductName,
        IsNull([1],0) as 'Week 1',
        IsNull([2],0) as 'Week 2',
        IsNull([3],0) as 'Week 3',
        IsNull([4],0) as 'Week 4',
        IsNull([5], 0) as 'Week 5'
Select  ProductName,
        DATEDIFF(week, DATEADD(MONTH, DATEDIFF(MONTH, 0, '2011-05-30'), 0), '2011-05-30') +1 as [Weeks],
        Sale as 'Sale'
From dbo.WeekReport

-- Only get rows where the date is the same as the DatePeriod
-- i.e DatePeriod is 30th May 2011 then only the weeks of May will be calculated
Where DatePart(Month, '2011-05-30')= DatePart(Month, @DatePeriod)
Pivot (Sum(Sale) for Weeks in ([1],[2],[3],[4],[5])) as pv


a   0   0   0   0   20
b   0   0   0   0   4
c   0   0   0   0   3

How can I change the app display name build with Flutter?

  • Review the default app manifest file, AndroidManifest.xml, located in <app dir>/android/app/src/main

  • Edit the android:label to your desired display name

Call a stored procedure with parameter in c#

cmd.Parameters.Add(String parameterName, Object value) is deprecated now. Instead use cmd.Parameters.AddWithValue(String parameterName, Object value)

Add(String parameterName, Object value) has been deprecated. Use AddWithValue(String parameterName, Object value)

There is no difference in terms of functionality. The reason they deprecated the cmd.Parameters.Add(String parameterName, Object value) in favor of AddWithValue(String parameterName, Object value) is to give more clarity. Here is the MSDN reference for the same

private void button1_Click(object sender, EventArgs e) {
  using (SqlConnection con = new SqlConnection(dc.Con)) {
    using (SqlCommand cmd = new SqlCommand("sp_Add_contact", con)) {
      cmd.CommandType = CommandType.StoredProcedure;

      cmd.Parameters.AddWithValue("@FirstName", SqlDbType.VarChar).Value = txtFirstName.Text;
      cmd.Parameters.AddWithValue("@LastName", SqlDbType.VarChar).Value = txtLastName.Text;


Javascript (+) sign concatenates instead of giving sum of variables

The reason you get that is the order of precendence of the operators, and the fact that + is used to both concatenate strings as well as perform numeric addition.

In your case, the concatenation of "question-" and i is happening first giving the string "question=1". Then another string concatenation with "1" giving "question-11".

You just simply need to give the interpreter a hint as to what order of prec endence you want.

divID = "question-" + (i+1);

Remove all files except some from a directory

Make the files immutable. Not even root will be allowed to delete them.

chattr +i textfile.txt backup.tar.gz script.php database.sql info.txt
rm *

All other files have been deleted.
Eventually you can reset them mutable.

chattr -i *

how to get files from <input type='file' .../> (Indirect) with javascript

If you are looking to style a file input element, look at open file dialog box in javascript. If you are looking to grab the files associated with a file input element, you must do something like this:

inputElement.onchange = function(event) {
   var fileList = inputElement.files;
   //TODO do something with fileList.  

See this MDN article for more info on the FileList type.

Note that the code above will only work in browsers that support the File API. For IE9 and earlier, for example, you only have access to the file name. The input element has no files property in non-File API browsers.

How to replace a string in a SQL Server Table Column

you need to replace path with the help of replace function.

update table_name set column_name = replace(column_name, 'oldstring', 'newstring')

here column_name refers to that column which you want to change.

Hope it will work.

How to get URL parameters with Javascript?

function getURLParameter(name) {
  return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec( || [null, ''])[1].replace(/\+/g, '%20')) || null;

So you can use:

myvar = getURLParameter('myvar');

jQuery UI Dialog individual CSS styling

According to the UI dialog documentation, the dialog plugin generates something like this:

<div class="ui-dialog ui-widget ui-widget-content ui-corner-all ui-draggable ui-resizable">
   <div class="ui-dialog-titlebar ui-widget-header ui-corner-all ui-helper-clearfix">
      <span id="ui-dialog-title-dialog" class="ui-dialog-title">Dialog title</span>
      <a class="ui-dialog-titlebar-close ui-corner-all" href="#"><span class="ui-icon ui-icon-closethick">close</span></a>
   <div class="ui-dialog-content ui-widget-content" id="dialog_style1">
      <p>One content</p>

That means what you can add to any class to exactly to first or second dialog using jQuery's closest() method. For example:



and then CSS it.

increment date by one month

All presented solutions are not working properly.
strtotime() and DateTime::add or DateTime::modify give sometime invalid results.
- 31.08.2019 + 1 month gives 01.10.2019 instead 30.09.2019
- 29.02.2020 + 1 year gives 01.03.2021 instead 28.02.2021
(tested on PHP 5.5, PHP 7.3)

Below is my function based on idea posted by Angelo that solves the problem:

// $time - unix time or date in any format accepted by strtotime() e.g. 2020-02-29  
// $days, $months, $years - values to add
// returns new date in format 2021-02-28
function addTime($time, $days, $months, $years)
    // Convert unix time to date format
    if (is_numeric($time))
    $time = date('Y-m-d', $time);

        $date_time = new DateTime($time);
    catch (Exception $e)
        echo $e->getMessage();

    if ($days)
    $date_time->add(new DateInterval('P'.$days.'D'));

    // Preserve day number
    if ($months or $years)
    $old_day = $date_time->format('d');

    if ($months)
    $date_time->add(new DateInterval('P'.$months.'M'));

    if ($years)
    $date_time->add(new DateInterval('P'.$years.'Y'));

    // Patch for adding months or years    
    if ($months or $years)
        $new_day = $date_time->format("d");

        // The day is changed - set the last day of the previous month
        if ($old_day != $new_day)
        $date_time->sub(new DateInterval('P'.$new_day.'D'));
    // You can chage returned format here
    return $date_time->format('Y-m-d');

Usage examples:

echo addTime('2020-02-29', 0, 0, 1); // add 1 year (result: 2021-02-28)
echo addTime('2019-08-31', 0, 1, 0); // add 1 month (result: 2019-09-30)
echo addTime('2019-03-15', 12, 2, 1); // add 12 days, 2 months, 1 year (result: 2019-09-30)

Best way to handle multiple constructors in Java

Consider using the Builder pattern. It allows for you to set default values on your parameters and initialize in a clear and concise way. For example:

    Book b = new Book.Builder("Catcher in the Rye").Isbn("12345")
       .Weight("5 pounds").build();

Edit: It also removes the need for multiple constructors with different signatures and is way more readable.

<Django object > is not JSON serializable

Another great way of solving it while using a model is by using the values() function.

def returnResponse(date):
    response = ScheduledDate.objects.filter(date__startswith=date).values()
    return Response(response)

go to character in vim

:goto 21490 will take you to the 21490th byte in the buffer.

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;

how to resolve DTS_E_OLEDBERROR. in ssis

I would start by turning off TCP offloading. There have been a few things that cause intermittent connectivity issues and this is the one that is usually the culprit.

Note: I have seen this setting cause problems on Win Server 2003 and Win Server 2008

How to get the real path of Java application at runtime?

The expression

new File(".").getAbsolutePath();

will get you the current working directory associated with the execution of JVM. However, the JVM does provide a wealth of other useful properties via the


interface. A list of these properties can be found here.

These will allow you to reference the current users directory, the temp directory and so on in a platform independent manner.

How to sort by column in descending order in Spark SQL?

import org.apache.spark.sql.functions.desc


C++ error: undefined reference to 'clock_gettime' and 'clock_settime'

Since glibc version 2.17, the library linking -lrt is no longer required.

The clock_* are now part of the main C library. You can see the change history of glibc 2.17 where this change was done explains the reason for this change:

+* The `clock_*' suite of functions (declared in <time.h>) is now available
+  directly in the main C library.  Previously it was necessary to link with
+  -lrt to use these functions.  This change has the effect that a
+  single-threaded program that uses a function such as `clock_gettime' (and
+  is not linked with -lrt) will no longer implicitly load the pthreads
+  library at runtime and so will not suffer the overheads associated with
+  multi-thread support in other code such as the C++ runtime library.

If you decide to upgrade glibc, then you can check the compatibility tracker of glibc if you are concerned whether there would be any issues using the newer glibc.

To check the glibc version installed on the system, run the command:

ldd --version

(Of course, if you are using old glibc (<2.17) then you will still need -lrt.)

Set select option 'selected', by value

a simple answer is, at html

<select name="ukuran" id="idUkuran">
    <option value="1000">pilih ukuran</option>
    <option value="11">M</option>
    <option value="12">L</option>
    <option value="13">XL</option>

on jquery, call below function by button or whatever


it simple and 100% works, coz its taken from my work... :) hope its help..

TypeError: int() argument must be a string, a bytes-like object or a number, not 'list'

What the error is telling, is that you can't convert an entire list into an integer. You could get an index from the list and convert that into an integer:

x = ["0", "1", "2"] 
y = int(x[0]) #accessing the zeroth element

If you're trying to convert a whole list into an integer, you are going to have to convert the list into a string first:

x = ["0", "1", "2"]
y = ''.join(x) # converting list into string
z = int(y)

If your list elements are not strings, you'll have to convert them to strings before using str.join:

x = [0, 1, 2]
y = ''.join(map(str, x))
z = int(y)

Also, as stated above, make sure that you're not returning a nested list.

Capitalize first letter. MySQL


CREATE DEFINER=`root`@`localhost` FUNCTION `UC_FIRST`(`oldWord` VARCHAR(255)) 

RETURNS varchar(255) CHARSET utf8



UPDATE tbl_name SET col_name = UC_FIRST(col_name);

How can I check that JButton is pressed? If the isEnable() is not work?

JButton has a model which answers these question:

  • isArmed(),
  • isPressed(),
  • isRollOVer()

etc. Hence you can ask the model for the answer you are seeking:

        System.out.println("the button is pressed");

RS256 vs HS256: What's the difference?

There is a difference in performance.

Simply put HS256 is about 1 order of magnitude faster than RS256 for verification but about 2 orders of magnitude faster than RS256 for issuing (signing).

 640,251  91,464.3 ops/s
  86,123  12,303.3 ops/s (RS256 verify)
   7,046   1,006.5 ops/s (RS256 sign)

Don't get hung up on the actual numbers, just think of them with respect of each other.


class Program
    static void Main(string[] args)
        foreach (var duration in new[] { 1, 3, 5, 7 })
            var t = TimeSpan.FromSeconds(duration);

            byte[] publicKey, privateKey;

            using (var rsa = new RSACryptoServiceProvider())
                publicKey = rsa.ExportCspBlob(false);
                privateKey = rsa.ExportCspBlob(true);

            byte[] key = new byte[64];

            using (var rng = new RNGCryptoServiceProvider())

            var s1 = new Stopwatch();
            var n1 = 0;

            using (var hs256 = new HMACSHA256(key))
                while (s1.Elapsed < t)
                    var hash = hs256.ComputeHash(privateKey);

            byte[] sign;

            using (var rsa = new RSACryptoServiceProvider())

                sign = rsa.SignData(privateKey, "SHA256");

            var s2 = new Stopwatch();
            var n2 = 0;

            using (var rsa = new RSACryptoServiceProvider())

                while (s2.Elapsed < t)
                    var success = rsa.VerifyData(privateKey, "SHA256", sign);

            var s3 = new Stopwatch();
            var n3 = 0;

            using (var rsa = new RSACryptoServiceProvider())

                while (s3.Elapsed < t)
                    rsa.SignData(privateKey, "SHA256");

            Console.WriteLine($"{s1.Elapsed.TotalSeconds:0} {n1,7:N0} {n1 / s1.Elapsed.TotalSeconds,9:N1} ops/s");
            Console.WriteLine($"{s2.Elapsed.TotalSeconds:0} {n2,7:N0} {n2 / s2.Elapsed.TotalSeconds,9:N1} ops/s");
            Console.WriteLine($"{s3.Elapsed.TotalSeconds:0} {n3,7:N0} {n3 / s3.Elapsed.TotalSeconds,9:N1} ops/s");

            Console.WriteLine($"RS256 is {(n1 / s1.Elapsed.TotalSeconds) / (n2 / s2.Elapsed.TotalSeconds),9:N1}x slower (verify)");
            Console.WriteLine($"RS256 is {(n1 / s1.Elapsed.TotalSeconds) / (n3 / s3.Elapsed.TotalSeconds),9:N1}x slower (issue)");

            // RS256 is about 7.5x slower, but it can still do over 10K ops per sec.

TypeError: object of type 'int' has no len() error assistance needed

May be it is the problem of using len() for an integer value. does not posses the len attribute in Python.

Error as:I will give u an example:

number= 1

Instead of use ths,

data = [1,2,3,4]

How do I rewrite URLs in a proxy response in NGINX

You may also need the following directive to be set before the first "sub_filter" for backend-servers with data compression:

proxy_set_header Accept-Encoding "";

Otherwise it may not work. For your example it will look like:

location /admin/ {
    proxy_pass http://localhost:8080/;
    proxy_set_header Accept-Encoding "";
    sub_filter "http://your_server/" "http://your_server/admin/";
    sub_filter_once off;

How to overwrite existing files in batch?

If the copy command is run from within a batch job you do not need to use the /Y switch: it will overwrite existing files.

is there a require for json in node.js

A nifty non-caching async one liner for node 15 modules:

import { readFile } from 'fs/promises';

const data = await readFile('{{ path }}').then(json => JSON.parse(json)).catch(() => null);

NodeJS: How to get the server's port?

The findandbind npm addresses this for express/restify/connect:

Saving a Excel File into .txt format without quotes

I just spent the better part of an afternoon on this

There are two common ways of writing to a file, the first being a direct file access "write" statement. This adds the quotes.

The second is the "ActiveWorkbook.SaveAs" or "ActiveWorksheet.SaveAs" which both have the really bad side effect of changing the filename of the active workbook.

The solution here is a hybrid of a few solutions I found online. It basically does this: 1) Copy selected cells to a new worksheet 2) Iterate through each cell one at a time and "print" it to the open file 3) Delete the temporary worksheet.

The function works on the selected cells and takes in a string for a filename or prompts for a filename.

Function SaveFile(myFolder As String) As String
tempSheetName = "fileWrite_temp"
SaveFile = "False"

Dim FilePath As String
Dim CellData As String
Dim LastCol As Long
Dim LastRow As Long

Set myRange = Selection

'Ask user for folder to save text file to.
If myFolder = "prompt" Then
    myFolder = Application.GetSaveAsFilename(fileFilter:="XML Files (*.xml), *.xml, All Files (*), *")
End If
If myFolder = "False" Then
End If

Open myFolder For Output As #2

'This temporarily adds a sheet named "Test."
Sheets.Add.Name = tempSheetName
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
    :=False, Transpose:=False

LastCol = ActiveSheet.UsedRange.SpecialCells(xlCellTypeLastCell).Column
LastRow = ActiveSheet.UsedRange.SpecialCells(xlCellTypeLastCell).Row

For i = 1 To LastRow
    For j = 1 To LastCol
        CellData = CellData + Trim(ActiveCell(i, j).Value) + "   "
    Next j

    Print #2, CellData; " "
    CellData = ""

Next i

Close #2

'Remove temporary sheet.
Application.ScreenUpdating = False
Application.DisplayAlerts = False
Application.DisplayAlerts = True
Application.ScreenUpdating = True
'Indicate save action.
MsgBox "Text File Saved to: " & vbNewLine & myFolder
SaveFile = myFolder

End Function

How to print bytes in hexadecimal using System.out.println?

byte test[] = new byte[3];
test[0] = 0x0A;
test[1] = 0xFF;
test[2] = 0x01;

for (byte theByte : test)

NOTE: test[1] = 0xFF; this wont compile, you cant put 255 (FF) into a byte, java will want to use an int.

you might be able to do...

test[1] = (byte) 0xFF;

I'd test if I was near my IDE (if I was near my IDE I wouln't be on Stackoverflow)

Read input numbers separated by spaces

I would recommend reading in the line into a string, then splitting it based on the spaces. For this, you can use the getline(...) function. The trick is having a dynamic sized data structure to hold the strings once it's split. Probably the easiest to use would be a vector.

#include <string>
#include <vector>
  string rawInput;
  vector<String> numbers;
  while( getline( cin, rawInput, ' ' ) )

So say the input looks like this:

Enter a number, or numbers separated by a space, between 1 and 1000.
10 5 20 1 200 7

You will now have a vector, numbers, that contains the elements: {"10","5","20","1","200","7"}.

Note that these are still strings, so not useful in arithmetic. To convert them to integers, we use a combination of the STL function, atoi(...), and because atoi requires a c-string instead of a c++ style string, we use the string class' c_str() member function.

  string temp = numbers.pop_back();//removes the last element from the string
  num = atoi( temp.c_str() ); //re-used your 'num' variable from your code

  ...//do stuff

Now there's some problems with this code. Yes, it runs, but it is kind of clunky, and it puts the numbers out in reverse order. Lets re-write it so that it is a little more compact:

#include <string>
string rawInput;
cout << "Enter a number, or numbers separated by a space, between 1 and 1000." << endl;
while( getline( cin, rawInput, ' ') )
  num = atoi( rawInput.c_str() );
  ...//do your stuff

There's still lots of room for improvement with error handling (right now if you enter a non-number the program will crash), and there's infinitely more ways to actually handle the input to get it in a usable number form (the joys of programming!), but that should give you a comprehensive start. :)

Note: I had the reference pages as links, but I cannot post more than two since I have less than 15 posts :/

Edit: I was a little bit wrong about the atoi behavior; I confused it with Java's string->Integer conversions which throw a Not-A-Number exception when given a string that isn't a number, and then crashes the program if the exception isn't handled. atoi(), on the other hand, returns 0, which is not as helpful because what if 0 is the number they entered? Let's make use of the isdigit(...) function. An important thing to note here is that c++ style strings can be accessed like an array, meaning rawInput[0] is the first character in the string all the way up to rawInput[length - 1].

#include <string>
#include <ctype.h>
string rawInput;
cout << "Enter a number, or numbers separated by a space, between 1 and 1000." << endl;
while( getline( cin, rawInput, ' ') )
  bool isNum = true;
  for(int i = 0; i < rawInput.length() && isNum; ++i)
    isNum = isdigit( rawInput[i]);

    num = atoi( rawInput.c_str() );
    ...//do your stuff
    cout << rawInput << " is not a number!" << endl;

The boolean (true/false or 1/0 respectively) is used as a flag for the for-loop, which steps through each character in the string and checks to see if it is a 0-9 digit. If any character in the string is not a digit, the loop will break during it's next execution when it gets to the condition "&& isNum" (assuming you've covered loops already). Then after the loop, isNum is used to determine whether to do your stuff, or to print the error message.

What is the difference between & vs @ and = in angularJS

Not my fiddle, but shows the difference. The key piece is:

            /* NOTE: Normally I would set my attributes and bindings
            to be the same name but I wanted to delineate between 
            parent and isolated scope. */                

String is immutable. What exactly is the meaning?

An immutable object is an object whose state cannot be modified after it is created.

So a = "ABC" <-- immutable object. "a" holds reference to the object. And, a = "DEF" <-- another immutable object, "a" holds reference to it now.

Once you assign a string object, that object can not be changed in memory.

In summary, what you did is to change the reference of "a" to a new string object.

How can I include null values in a MIN or MAX?

In my expression, count(enddate) counts how many rows where the enddate column is not null. The count(*) expression counts total rows. By comparing, you can easily tell if any value in the enddate column contains null. If they are identical, then max(enddate) is the result. Otherwise the case will default to returning null which is also the answer. This is a very popular way to do this exact check.

SELECT recordid, 
case when count(enddate) = count(*) then max(enddate) end
FROM tmp 
GROUP BY recordid

Update Eclipse with Android development tools v. 23

Google has released ADT v23.0.2. This solved many problems of previous ADT version 23.


  • Menu Help ? Install New Software...
  • For "Work with", select the Android source Work with Android source
  • Tick ADT v23.0 for installation, then click "Next"
  • Eclipse will show "Install Remediation Page" since there is conflict with previous version. (If it does not, see below.) Select "Update my installation to be compatible with items being installed" to uninstall the old version and install the new one. After that, proceed with the usual steps.

Install remediation page

Note: When I installed the new version of ADT, I didn't include the new version of "Android Native Development Tools" package. Instead, I installed the rest of packages first, and then installed "Android Native Development Tools". For a reason, if I try to install all the new packages including "Android Native Development Tools", the installation fails.

If there is no "Remediation page", the only way to remove the ADT plugin from Eclipse is to go to menu Help ? About Eclipse ? Installation Details and uninstall from there. But there is a risk of uninstalling Eclipse itself.

Opening port 80 EC2 Amazon web services

Some quick tips:

  1. Disable the inbuilt firewall on your Windows instances.
  2. Use the IP address rather than the DNS entry.
  3. Create a security group for tcp ports 1 to 65000 and for source It's obviously not to be used for production purposes, but it will help avoid the Security Groups as a source of problems.
  4. Check that you can actually ping your server. This may also necessitate some Security Group modification.

How to expire a cookie in 30 minutes using jQuery?

30 minutes is 30 * 60 * 1000 miliseconds. Add that to the current date to specify an expiration date 30 minutes in the future.

 var date = new Date();
 var minutes = 30;
 date.setTime(date.getTime() + (minutes * 60 * 1000));
 $.cookie("example", "foo", { expires: date });

JavaScript: How to pass object by value?

Use Object.assign()


var a = {some: object};
var b = new Object;
Object.assign(b, a);
// b now equals a, but not by association.

A cleaner example that does the same thing:

var a = {some: object};
var b = Object.assign({}, a);
// Once again, b now equals a.

Select datatype of the field in postgres

If you like 'Mike Sherrill' solution but don't want to use psql, I used this query to get the missing information:

select column_name,
    when domain_name is not null then domain_name
    when data_type='character varying' THEN 'varchar('||character_maximum_length||')'
    when data_type='numeric' THEN 'numeric('||numeric_precision||','||numeric_scale||')'
    else data_type
end as myType
from information_schema.columns
where table_name='test'

with result:

column_name |     myType
 test_id     | test_domain
 test_vc     | varchar(15)
 test_n      | numeric(15,3)
 big_n       | bigint
 ip_addr     | inet

Converting double to string

This code compiles and works for me. It converts a double to a string using the calls you tried.

public class TestDouble {

    public static void main(String[] args) {
        double total = 44;
        String total2 = Double.toString(total);

        System.out.println("Double is " + total2);

I am puzzled by your seeing the NumberFormatException. Look at the stack trace. I'm guessing you have other code that you are not showing in your example that is causing that exception to be thrown.

Insert current date/time using now() in a field using MySQL/PHP

These both work fine for me...

  $db = mysql_connect('localhost','user','pass');

  $stmt = "INSERT INTO `test` (`first`,`last`,`whenadded`) VALUES ".
  $rslt = mysql_query($stmt);

  $stmt = "INSERT INTO `users` (`first`,`last`,`whenadded`) VALUES ".
          "('{$first}', '{$last}', CURRENT_TIMESTAMP)";
  $rslt = mysql_query($stmt);


Side note: mysql_query() is not the best way to connect to MySQL in current versions of PHP.

How to activate an Anaconda environment

Note that the command for activating an environment has changed in Conda version 4.4. The recommended way of activating an environment is now conda activate myenv instead of source activate myenv. To enable the new syntax, you should modify your .bashrc file. The line that currently reads something like

export PATH="<path_to_your_conda_install>/bin:$PATH"

Should be changed to

. <path_to_your_conda_install>/etc/profile.d/

This only adds the conda command to the path, but does not yet activate the base environment (which was previously called root). To do also that, add another line

conda activate base

after the first command. See all the details in Anaconda's blog post from December 2017. (I think that this page is currently missing a newline between the two lines, it says .../conda.shconda activate base).

(This answer is valid for Linux, but it might be relevant for Windows and Mac as well)

resource error in android studio after update: No Resource Found

It's works just when the build.grade was changed to that:

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "blablabla"
        minSdkVersion 15
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), ''

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile ''

Class 'App\Http\Controllers\DB' not found and I also cannot use a new Model

Use the backslash before db on the header and you can use it then typically as you wrote it before.

Here is the example:

Use \DB;

Then inside your controller class you can use as you did before, like that ie :

$item = DB::table('items')->get();

How to Toggle a div's visibility by using a button click

jQuery would be the easiest way if you want to use it, but this should work.

function showHide(){
    var e = document.getElementById('e');

    if ( !== 'none' ) { = 'none';
    } else { = '';

Why a function checking if a string is empty always returns true?

PHP have a built in function called empty() the test is done by typing if(empty($string)){...} Reference : php empty

Drawing in Java using Canvas

Why would the first way not work. Canvas object is created and the size is set and the grahpics are set. I always find this strange. Also if a class extends JComponent you can override the


and then shouldn't you be able to create and instance of the class inside of another class and then just call NewlycreateinstanceOfAnyClass.repaint();

I have tried this approach for some game programming I have been working and it doesn't seem to work the way I think that it should be.

Doug Hauf

Web API Routing - api/{controller}/{action}/{id} "dysfunctions" api/{controller}/{id}

To differentiate the routes, try adding a constraint that id must be numeric:

         name: "DefaultApi",
         routeTemplate: "api/{controller}/{id}",
         constraints: new { id = @"\d+" }, // Only matches if "id" is one or more digits.
         defaults: new { id = System.Web.Http.RouteParameter.Optional }

How to clear an EditText on click?

Are you looking for behavior similar to the x that shows up on the right side of text fields on an iphone that clears the text when tapped? It's called clearButtonMode there. Here is how to create that same functionality in an Android EditText view:

String value = "";//any text you are pre-filling in the EditText

final EditText et = new EditText(this);
final Drawable x = getResources().getDrawable(R.drawable.presence_offline);//your x image, this one from standard android images looks pretty good actually
x.setBounds(0, 0, x.getIntrinsicWidth(), x.getIntrinsicHeight());
et.setCompoundDrawables(null, null, value.equals("") ? null : x, null);
et.setOnTouchListener(new OnTouchListener() {
    public boolean onTouch(View v, MotionEvent event) {
        if (et.getCompoundDrawables()[2] == null) {
            return false;
        if (event.getAction() != MotionEvent.ACTION_UP) {
            return false;
        if (event.getX() > et.getWidth() - et.getPaddingRight() - x.getIntrinsicWidth()) {
            et.setCompoundDrawables(null, null, null, null);
        return false;
et.addTextChangedListener(new TextWatcher() {
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        et.setCompoundDrawables(null, null, et.getText().toString().equals("") ? null : x, null);

    public void afterTextChanged(Editable arg0) {

    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

MySQL error 1241: Operand should contain 1 column(s)

Just remove the ( and the ) on your SELECT statement:

insert into table2 (Name, Subject, student_id, result)
select Name, Subject, student_id, result
from table1;

How to chain scope queries with OR instead of AND?

According to this pull request, Rails 5 now supports the following syntax for chaining queries:

Post.where(id: 1).or(Post.where(id: 2))

There's also a backport of the functionality into Rails 4.2 via this gem.

Reference member variables as class members

C++ provides a good mechanism to manage the life time of an object though class/struct constructs. This is one of the best features of C++ over other languages.

When you have member variables exposed through ref or pointer it violates the encapsulation in principle. This idiom enables the consumer of the class to change the state of an object of A without it(A) having any knowledge or control of it. It also enables the consumer to hold on to a ref/pointer to A's internal state, beyond the life time of the object of A. This is bad design. Instead the class could be refactored to hold a ref/pointer to the shared object (not own it) and these could be set using the constructor (Mandate the life time rules). The shared object's class may be designed to support multithreading/concurrency as the case may apply.

How to iterate over a column vector in Matlab?

In Matlab, you can iterate over the elements in the list directly. This can be useful if you don't need to know which element you're currently working on.

Thus you can write

for elm = list
%# do something with the element

Note that Matlab iterates through the columns of list, so if list is a nx1 vector, you may want to transpose it.

How to combine 2 plots (ggplot) into one plot?

Creating a single combined plot with your current data set up would look something like this

p <- ggplot() +
      # blue plot
      geom_point(data=visual1, aes(x=ISSUE_DATE, y=COUNTED)) + 
      geom_smooth(data=visual1, aes(x=ISSUE_DATE, y=COUNTED), fill="blue",
        colour="darkblue", size=1) +
      # red plot
      geom_point(data=visual2, aes(x=ISSUE_DATE, y=COUNTED)) + 
      geom_smooth(data=visual2, aes(x=ISSUE_DATE, y=COUNTED), fill="red",
        colour="red", size=1)

however if you could combine the data sets before plotting then ggplot will automatically give you a legend, and in general the code looks a bit cleaner

visual1$group <- 1
visual2$group <- 2

visual12 <- rbind(visual1, visual2)

p <- ggplot(visual12, aes(x=ISSUE_DATE, y=COUNTED, group=group, col=group, fill=group)) +
      geom_point() +

What is the mouse down selector in CSS?

I recently found out that :active:focus does the same thing in css as :active:hover if you need to override a custom css library, they might use both.

How to install PostgreSQL's pg gem on Ubuntu?

Simple solution for ubuntu users...

First uninstall all postgres packages, then run these commads...

sudo apt-get install postgresql
sudo apt-get install postgresql-client libpq5 libpq-dev

# for rvm (single user)
mv ~/.rvm/usr/lib ~/.rvm/usr/lib_rvm 

# for rvm (multi-user)
mv /usr/local/rvm/usr/lib /usr/local/rvm/usr/lib_rvm

gem install pg  --   --with-pg-lib=/usr/lib

Then run 'bundle install'. Every thing will be fine. Have a good day!

Getting the difference between two sets

Just to put one example here (system is in existingState, and we want to find elements to remove (elements that are not in newState but are present in existingState) and elements to add (elements that are in newState but are not present in existingState) :

public class AddAndRemove {

  static Set<Integer> existingState = Set.of(1,2,3,4,5);
  static Set<Integer> newState = Set.of(0,5,2,11,3,99);

  public static void main(String[] args) {

    Set<Integer> add = new HashSet<>(newState);

    System.out.println("Elements to add : " + add);

    Set<Integer> remove = new HashSet<>(existingState);

    System.out.println("Elements to remove : " + remove);


would output this as a result:

Elements to add : [0, 99, 11]
Elements to remove : [1, 4]

SonarQube not picking up Unit Test Coverage

You were missing a few important sonar properties, Here is a sample from one of my builds:

sonar.projectName=Project Name

The error in Jenkins console output can be pretty useful for getting code coverage to work.

Project coverage is set to 0% since there is no directories with classes.
Indicates that you have not set the Sonar.Binaries property correctly

No information about coverage per test
Indicates you have not set the Sonar.Tests property properly

Coverage information was not collected. Perhaps you forget to include debug information into compiled classes? Indicates that the sonar.binaries property was set correctly, but those files were not compiled in debug mode, and they need to be

No 'Access-Control-Allow-Origin' header in Angular 2 app

Unfortunately, that's not an Angular2 error, that's an error your browser is running into (i.e. outside of your app).

That CORS header will have to be added to that endpoint on the server before you can make ANY requests.

Python Database connection Close

You might try turning off pooling, which is enabled by default. See this discussion for more information.

import pyodbc
pyodbc.pooling = False
conn = pyodbc.connect('DRIVER=MySQL ODBC 5.1 driver;SERVER=localhost;DATABASE=spt;UID=who;PWD=testest') 

csr = conn.cursor()  
del csr

How to export library to Jar in Android Studio?

Here's yet another, slightly different answer with a few enhancements.

This code takes the .jar right out of the .aar. Personally, that gives me a bit more confidence that the bits being shipped via .jar are the same as the ones shipped via .aar. This also means that if you're using ProGuard, the output jar will be obfuscated as desired.

I also added a super "makeJar" task, that makes jars for all build variants.

task(makeJar) << {
    // Empty. We'll add dependencies for this task below

// Generate jar creation tasks for all build variants
android.libraryVariants.all { variant ->
    String taskName = "makeJar${}"

    // Create a jar by extracting it from the assembled .aar
    // This ensures that products distributed via .aar and .jar exactly the same bits
    task (taskName, type: Copy) {
        String archiveName = "${}-${}"
        String outputDir = "${buildDir.getPath()}/outputs"

        dependsOn "assemble${}"
        rename ('classes.jar', "${archiveName}-${variant.mergedFlavor.versionName}.jar")

    makeJar.dependsOn tasks[taskName]

For the curious reader, I struggled to determine the correct variables and parameters that the plugin uses to name .aar files. I finally found them in the Android Open Source Project here.

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

In /data/app but for copy protection I don't think you can access it.

ascending/descending in LINQ - can one change the order via parameter?

In addition to the beautiful solution given by @Jon Skeet, I also needed ThenBy and ThenByDescending, so I am adding it based on his solution:

    public static IOrderedEnumerable<TSource> ThenByWithDirection<TSource, TKey>(
         this IOrderedEnumerable<TSource> source, 
         Func<TSource, TKey> keySelector,  
         bool descending)
        return descending ? 
               source.ThenByDescending(keySelector) :

How to add multiple font files for the same font?

As of CSS3, the spec has changed, allowing for only a single font-style. A comma-separated list (per CSS2) will be treated as if it were normal and override any earlier (default) entry. This will make fonts defined in this way appear italic permanently.

@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans.ttf");
@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans-Bold.ttf");
    font-weight: bold;
@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans-Oblique.ttf");
    font-style: italic;
@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans-BoldOblique.ttf");
    font-weight: bold;
    font-style: italic;
@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans-Oblique.ttf");
    font-style: oblique;
@font-face {
    font-family: "DejaVu Sans";
    src: url("fonts/DejaVuSans-BoldOblique.ttf");
    font-weight: bold;
    font-style: oblique;

In most cases, italic will probably be sufficient and oblique rules won't be necessary if you take care to define whichever you will use and stick to it.

Ping site and return result in PHP

Here's one:


function ping($host, $port, $timeout) { 
  $tB = microtime(true); 
  $fP = fSockOpen($host, $port, $errno, $errstr, $timeout); 
  if (!$fP) { return "down"; } 
  $tA = microtime(true); 
  return round((($tA - $tB) * 1000), 0)." ms"; 

//Echoing it will display the ping if the host is up, if not it'll say "down".
echo ping("", 80, 10);  

Ignore Typescript Errors "property does not exist on value of type"

In my particular project I couldn't get it to work, and used declare var $;. Not a clean/recommended solution, it doesnt recognise the JQuery variables, but I had no errors after using that (and had to for my automatic builds to succeed).

How do I add a reference to the MySQL connector for .NET?

This is an older question, but I found it yesterday while struggling with getting the MySQL Connector reference working properly on examples I'd found on the web. I'm working with VS 2010 on Win7 64 bit but have to work with .NET 3.5.

As others have stated, you need to download the .Net & Mono versions (I don't know why this is true, but it's what I've found works). The link to the connectors is given above in the earlier answers.

  • Extract the connectors somewhere convenient.
  • Open the project in Visual Studio, then on the menu bar navigate to Solution Explorer (View > Solution Explorer), and choose Properties (first box on the far left of the toolbar. The Solution Explorer shows up in the top right pane for me, but YMMV).
  • In Properties, select References & locate the instance for It's likely to have a yellow bang on it (Yellow triangle with exclamation point in it). Remove it.
  • Then on the menu bar, navigate to Project > Add Reference... > Browse > point to where you downloaded the connectors. I have only been able to get the V2 version to work, but that may be a factor of my platform, not sure.
  • Clean & build your application. You should now be able to use the MySQL connectors to talk to your database.
  • You can also now downgrade your .NET instance if you need to (we're constrained to .NET 3.5, but wants 4.0 at the time of my writing this). On the menu bar, navigate to the properties of your project (Project > Properties). Choose the Application tab > Target framework > Choose which .NET framework you want to use. You have to build the application at least once before you can change the .NET framework. Once you built once the connector will no longer complain about the lower version of .NET.

What does void do in java?

Void doesn't return anything; it tells the compiler the method doesn't have a return value.

Counting Number of Letters in a string variable

You can simply use

int numberOfLetters = yourWord.Length;

or to be cool and trendy, use LINQ like this :

int numberOfLetters = yourWord.ToCharArray().Count();

and if you hate both Properties and LINQ, you can go old school with a loop :

int numberOfLetters = 0;
foreach (char letter in yourWord)

How to find if a native DLL file is compiled as x64 or x86?

The Magic field of the IMAGE_OPTIONAL_HEADER (though there is nothing optional about the header in Windows executable images (DLL/EXE files)) will tell you the architecture of the PE.

Here's an example of grabbing the architecture from a file.

public static ushort GetImageArchitecture(string filepath) {
    using (var stream = new System.IO.FileStream(filepath, System.IO.FileMode.Open, System.IO.FileAccess.Read))
    using (var reader = new System.IO.BinaryReader(stream)) {
        //check the MZ signature to ensure it's a valid Portable Executable image
        if (reader.ReadUInt16() != 23117) 
            throw new BadImageFormatException("Not a valid Portable Executable image", filepath);

        // seek to, and read, e_lfanew then advance the stream to there (start of NT header)
        stream.Seek(0x3A, System.IO.SeekOrigin.Current); 
        stream.Seek(reader.ReadUInt32(), System.IO.SeekOrigin.Begin);

        // Ensure the NT header is valid by checking the "PE\0\0" signature
        if (reader.ReadUInt32() != 17744)
            throw new BadImageFormatException("Not a valid Portable Executable image", filepath);

        // seek past the file header, then read the magic number from the optional header
        stream.Seek(20, System.IO.SeekOrigin.Current); 
        return reader.ReadUInt16();

The only two architecture constants at the moment are:

0x10b - PE32
0x20b - PE32+


UPDATE It's been a while since I posted this answer, yet I still see that it gets a few upvotes now and again so I figured it was worth updating. I wrote a way to get the architecture of a Portable Executable image, which also checks to see if it was compiled as AnyCPU. Unfortunately the answer is in C++, but it shouldn't be too hard to port to C# if you have a few minutes to look up the structures in WinNT.h. If people are interested I'll write a port in C#, but unless people actually want it I wont spend much time stressing about it.

#include <Windows.h>

#define MKPTR(p1,p2) ((DWORD_PTR)(p1) + (DWORD_PTR)(p2))

typedef enum _pe_architecture {
    PE_ARCHITECTURE_X86     = 0x010B,
    PE_ARCHITECTURE_x64     = 0x020B

    for(unsigned long i = 0; i < pNt->FileHeader.NumberOfSections; ++i, ++pSecHd) {
        // Lookup which section contains this RVA so we can translate the VA to a file offset
        if (rva >= pSecHd->VirtualAddress && rva < (pSecHd->VirtualAddress + pSecHd->Misc.VirtualSize)) {
            DWORD delta = pSecHd->VirtualAddress - pSecHd->PointerToRawData;
            return (LPVOID)MKPTR(pDos, rva - delta);
    return NULL;

PE_ARCHITECTURE GetImageArchitecture(void *pImageBase) {
    // Parse and validate the DOS header
    if (IsBadReadPtr(pDosHd, sizeof(pDosHd->e_magic)) || pDosHd->e_magic != IMAGE_DOS_SIGNATURE)

    // Parse and validate the NT header
    IMAGE_NT_HEADERS *pNtHd = (IMAGE_NT_HEADERS*)MKPTR(pDosHd, pDosHd->e_lfanew);
    if (IsBadReadPtr(pNtHd, sizeof(pNtHd->Signature)) || pNtHd->Signature != IMAGE_NT_SIGNATURE)

    // First, naive, check based on the 'Magic' number in the Optional Header.
    PE_ARCHITECTURE architecture = (PE_ARCHITECTURE)pNtHd->OptionalHeader.Magic;

    // If the architecture is x86, there is still a possibility that the image is 'AnyCPU'
    if (architecture == PE_ARCHITECTURE_X86) {
        IMAGE_DATA_DIRECTORY comDirectory = pNtHd->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_COM_DESCRIPTOR];
        if (comDirectory.Size) {
            IMAGE_COR20_HEADER *pClrHd = (IMAGE_COR20_HEADER*)GetOffsetFromRva(pDosHd, pNtHd, comDirectory.VirtualAddress);
            // Check to see if the CLR header contains the 32BITONLY flag, if not then the image is actually AnyCpu
            if ((pClrHd->Flags & COMIMAGE_FLAGS_32BITREQUIRED) == 0)
                architecture = PE_ARCHITECTURE_ANYCPU;

    return architecture;

The function accepts a pointer to an in-memory PE image (so you can choose your poison on how to get it their; memory-mapping or reading the whole thing into memory...whatever).

Unicode via CSS :before

The code points used in icon font tricks are usually Private Use code points, which means that they have no generally defined meaning and should not be used in open information interchange, only by private agreement between interested parties. However, Private Use code points can be represented as any other Unicode value, e.g. in CSS using a notation like \f066, as others have answered. You can even enter the code point as such, if your document is UTF-8 encoded and you know how to type an arbitrary Unicode value by its number in your authoring environment (but of course it would normally be displayed using a symbol for an unknown character).

However, this is not the normal way of using icon fonts. Normally you use a CSS file provided with the font and use constructs like <span class="icon-resize-small">foo</span>. The CSS code will then take care of inserting the symbol at the start of the element, and you don’t need to know the code point number.

Do we have router.reload in vue-router?

Here's a solution if you just want to update certain components on a page:

In template

<Component1 :key="forceReload" />
<Component2 :key="forceReload" />

In data

data() {
  return {
    forceReload: 0

In methods:

   Methods: {
     reload() {
        this.forceReload += 1

Use a unique key and bind it to a data property for each one you want to update (I typically only need this for a single component, two at the most. If you need more, I suggest just refreshing the full page using the other answers.

I learned this from Michael Thiessen's post:

How can I get all the request headers in Django?

This is another way to do it, very similar to Manoj Govindan's answer above:

import re
regex_http_          = re.compile(r'^HTTP_.+$')
regex_content_type   = re.compile(r'^CONTENT_TYPE$')
regex_content_length = re.compile(r'^CONTENT_LENGTH$')

request_headers = {}
for header in request.META:
    if regex_http_.match(header) or regex_content_type.match(header) or regex_content_length.match(header):
        request_headers[header] = request.META[header]

That will also grab the CONTENT_TYPE and CONTENT_LENGTH request headers, along with the HTTP_ ones. request_headers['some_key] == request.META['some_key'].

Modify accordingly if you need to include/omit certain headers. Django lists a bunch, but not all, of them here:

Django's algorithm for request headers:

  1. Replace hyphen - with underscore _
  2. Convert to UPPERCASE.
  3. Prepend HTTP_ to all headers in original request, except for CONTENT_TYPE and CONTENT_LENGTH.

The values of each header should be unmodified.

Capturing TAB key in text box

there is a problem in best answer given by ScottKoon

here is it

} else if(el.attachEvent ) {
    myInput.attachEvent('onkeydown',this.keyHandler); /* damn IE hack */

Should be

} else if(myInput.attachEvent ) {
    myInput.attachEvent('onkeydown',this.keyHandler); /* damn IE hack */

Due to this it didn't work in IE. Hoping that ScottKoon will update code

Command / failed with exit code 1

Do a clean. product > clean . Terminal purge & reboot didn't work for me, cleaning did.

How to Get the HTTP Post data in C#?

This code reads the raw input stream from the HTTP request. Use this if the data isn't available in Request.Form or other model bindings or if you need access to the bytes/text as it comes.

using(var reader = new StreamReader(Request.InputStream))
    content = reader.ReadToEnd();

How to convert current date into string in java?

public static Date getDateByString(String dateTime) {
        if(dateTime==null || dateTime.isEmpty()) {
            return null;
            String modified = dateTime + ".000+0000";
            DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
            Date dateObj = new Date();
            Date dateObj1 = new Date();
            try {
                if (dateTime != null) {
                    dateObj = formatter.parse(modified);

            } catch (ParseException e) {

            return dateObj;


Remove trailing zeros

I found an elegant solution from


decimal v=2.4200M;

v.ToString("#.######"); // Will return 2.42. The number of # is how many decimal digits you support.

import httplib ImportError: No module named httplib

I had this issue when I was trying to make my Docker container smaller. It was because I'd installed Python 2.7 with:

apt-get install -y --no-install-recommends python

And I should not have included the --no-install-recommends flag:

apt-get install -y python

Is there a way to get a textarea to stretch to fit its content without using PHP or JavaScript?

Not really. This is normally done using javascript.

there is a good discussion of ways of doing this here...

Autosizing textarea using Prototype

Regex that accepts only numbers (0-9) and NO characters

Your regex ^[0-9] matches anything beginning with a digit, including strings like "1A". To avoid a partial match, append a $ to the end:


This accepts any number of digits, including none. To accept one or more digits, change the * to +. To accept exactly one digit, just remove the *.

UPDATE: You mixed up the arguments to IsMatch. The pattern should be the second argument, not the first:

if (!System.Text.RegularExpressions.Regex.IsMatch(textbox.Text, "^[0-9]*$"))

CAUTION: In JavaScript, \d is equivalent to [0-9], but in .NET, \d by default matches any Unicode decimal digit, including exotic fare like ? (Myanmar 2) and ? (N'Ko 9). Unless your app is prepared to deal with these characters, stick with [0-9] (or supply the RegexOptions.ECMAScript flag).

T-SQL: Looping through an array of known values

I usually use the following approach

    id INT IDENTITY(1,1)
    ,parameter INT

select parameter from some_table where some_condition -- here you populate your parameters

declare @i int
declare @n int
declare @myId int
select @i = min(id), @n = max(id) from @calls
while @i <= @n
        @myId = parameter
    where id = @i

        EXECUTE p_MyInnerProcedure @myId
    set @i = @i+1

Check if a string is a palindrome

Using LINQ and off course far from the best solution

var original = "ankYkna";
var reversed = new string(original.Reverse().ToArray());
var palindrom = original == reversed;

Docker is installed but Docker Compose is not ? why?

I'm on debian, I found something quite natural to do :

apt-get install docker-compose

and it did the job (not tested on centos)

Python and pip, list all versions of a package that's available?

This is Py3.9+ version of Limmy+EricChiang 's solution.

import json
import urllib.request
from distutils.version import StrictVersion

# print PyPI versions of package
def versions(package_name):
    url = "" % (package_name,)
    data = json.load(urllib.request.urlopen(url))
    versions = list(data["releases"])
    sortfunc = lambda x: StrictVersion(x.replace('rc', 'b').translate(str.maketrans('cdefghijklmn', 'bbbbbbbbbbbb')))
    return versions

ConcurrentHashMap vs Synchronized HashMap

A simple performance test for ConcurrentHashMap vs Synchronized HashMap . The test flow is calling put in one thread and calling get in three threads on Map concurrently. As @trshiv said, ConcurrentHashMap has higher throughput and speed for whose reading operation without lock. The result is when operation times is over 10^7, ConcurrentHashMap is 2x faster than Synchronized HashMap.

TimeSpan to DateTime conversion

A problem with all of the above is that the conversion returns the incorrect number of days as specified in the TimeSpan.
Using the above, the below returns 3 and not 2.

Ideas on how to preserve the 2 days in the TimeSpan arguments and return them as the DateTime day?

public void should_return_totaldays()
    _ts = new TimeSpan(2, 1, 30, 10);
    var format = "dd";
    var returnedVal = _ts.ToString(format);
    Assert.That(returnedVal, Is.EqualTo("2")); //returns 3 not 2

Terminating a Java Program

What does return; mean?

return; really means it returns nothing void. That's it.

why return; or other codes can write below the statement of System.exit(0);

It is allowed since compiler doesn't know calling System.exit(0) will terminate the JVM. The compiler will just give a warning - unnecessary return statement

Set LIMIT with doctrine 2?

$query_ids = $this->getEntityManager()
        FROM MuzichCoreBundle:Element e_
        WHERE [...]
        GROUP BY")

HERE in the second query the result of the first query should be passed ..

$query_select = "SELECT e
      FROM MuzichCoreBundle:Element e 
      WHERE IN (".$query_ids->getResult().")
      ORDER BY e.created DESC, DESC"

$query = $this->getEntityManager()

$resultCollection = $query->getResult();

How to fix 'Object arrays cannot be loaded when allow_pickle=False' for imdb.load_data() function?

The easiest way is to change setting allow_pickle=True to np.load at the line where throws error.

"Cannot send session cache limiter - headers already sent"

"Headers already sent" means that your PHP script already sent the HTTP headers, and as such it can't make modifications to them now.

Check that you don't send ANY content before calling session_start. Better yet, just make session_start the first thing you do in your PHP file (so put it at the absolute beginning, before all HTML etc).

How to hide command output in Bash

Use this.

} &> /dev/null


To eliminate output from commands, you have two options:

  • Close the output descriptor file, which keeps it from accepting any more input. That looks like this:

    your_command "Is anybody listening?" >&-

    Usually, output goes either to file descriptor 1 (stdout) or 2 (stderr). If you close a file descriptor, you'll have to do so for every numbered descriptor, as &> (below) is a special BASH syntax incompatible with >&-:

    /your/first/command >&- 2>&-

    Be careful to note the order: >&- closes stdout, which is what you want to do; &>- redirects stdout and stderr to a file named - (hyphen), which is not what what you want to do. It'll look the same at first, but the latter creates a stray file in your working directory. It's easy to remember: >&2 redirects stdout to descriptor 2 (stderr), >&3 redirects stdout to descriptor 3, and >&- redirects stdout to a dead end (i.e. it closes stdout).

    Also beware that some commands may not handle a closed file descriptor particularly well ("write error: Bad file descriptor"), which is why the better solution may be to...

  • Redirect output to /dev/null, which accepts all output and does nothing with it. It looks like this:

    your_command "Hello?" > /dev/null

    For output redirection to a file, you can direct both stdout and stderr to the same place very concisely, but only in bash:

    /your/first/command &> /dev/null

Finally, to do the same for a number of commands at once, surround the whole thing in curly braces. Bash treats this as a group of commands, aggregating the output file descriptors so you can redirect all at once. If you're familiar instead with subshells using ( command1; command2; ) syntax, you'll find the braces behave almost exactly the same way, except that unless you involve them in a pipe the braces will not create a subshell and thus will allow you to set variables inside.

} &> /dev/null

See the bash manual on redirections for more details, options, and syntax.

Applying an ellipsis to multiline text

Unfortunately no with current state of affairs in CSS.

Ellipsis rendering has prerequisite white-space:nowrap that effectively means: ellipsis are drawn on single line text containers only.

A circular reference was detected while serializing an object of type 'SubSonic.Schema .DatabaseColumn'.

JSON, like xml and various other formats, is a tree-based serialization format. It won't love you if you have circular references in your objects, as the "tree" would be:

root B => child A => parent B => child A => parent B => ...

There are often ways of disabling navigation along a certain path; for example, with XmlSerializer you might mark the parent property as XmlIgnore. I don't know if this is possible with the json serializer in question, nor whether DatabaseColumn has suitable markers (very unlikely, as it would need to reference every serialization API)

splitting a string into an array in C++ without using vector

#include <iostream>
#include <sstream>
#include <vector>
using namespace std;

int main() {

    string s1="split on     whitespace";
    istringstream iss(s1);
    vector<string> result;
    for(string s;iss>>s;)
    int n=result.size();
    for(int i=0;i<n;i++)
    return 0;



"Debug certificate expired" error in Eclipse Android plugins

First close the eclipse then

Open CMD by Window Key + R or via Run as Admin

Follows the following step

del "%USERPROFILE%\.android\debug.keystore"
keytool -genkey -v -keystore "%USERPROFILE%\.android\debug.keystore" -alias androiddebugkey -storepass android -keypass android -keyalg RSA -validity 30000

after this restart eclipse.

Difference between volatile and synchronized in Java

It's important to understand that there are two aspects to thread safety.

  1. execution control, and
  2. memory visibility

The first has to do with controlling when code executes (including the order in which instructions are executed) and whether it can execute concurrently, and the second to do with when the effects in memory of what has been done are visible to other threads. Because each CPU has several levels of cache between it and main memory, threads running on different CPUs or cores can see "memory" differently at any given moment in time because threads are permitted to obtain and work on private copies of main memory.

Using synchronized prevents any other thread from obtaining the monitor (or lock) for the same object, thereby preventing all code blocks protected by synchronization on the same object from executing concurrently. Synchronization also creates a "happens-before" memory barrier, causing a memory visibility constraint such that anything done up to the point some thread releases a lock appears to another thread subsequently acquiring the same lock to have happened before it acquired the lock. In practical terms, on current hardware, this typically causes flushing of the CPU caches when a monitor is acquired and writes to main memory when it is released, both of which are (relatively) expensive.

Using volatile, on the other hand, forces all accesses (read or write) to the volatile variable to occur to main memory, effectively keeping the volatile variable out of CPU caches. This can be useful for some actions where it is simply required that visibility of the variable be correct and order of accesses is not important. Using volatile also changes treatment of long and double to require accesses to them to be atomic; on some (older) hardware this might require locks, though not on modern 64 bit hardware. Under the new (JSR-133) memory model for Java 5+, the semantics of volatile have been strengthened to be almost as strong as synchronized with respect to memory visibility and instruction ordering (see For the purposes of visibility, each access to a volatile field acts like half a synchronization.

Under the new memory model, it is still true that volatile variables cannot be reordered with each other. The difference is that it is now no longer so easy to reorder normal field accesses around them. Writing to a volatile field has the same memory effect as a monitor release, and reading from a volatile field has the same memory effect as a monitor acquire. In effect, because the new memory model places stricter constraints on reordering of volatile field accesses with other field accesses, volatile or not, anything that was visible to thread A when it writes to volatile field f becomes visible to thread B when it reads f.

-- JSR 133 (Java Memory Model) FAQ

So, now both forms of memory barrier (under the current JMM) cause an instruction re-ordering barrier which prevents the compiler or run-time from re-ordering instructions across the barrier. In the old JMM, volatile did not prevent re-ordering. This can be important, because apart from memory barriers the only limitation imposed is that, for any particular thread, the net effect of the code is the same as it would be if the instructions were executed in precisely the order in which they appear in the source.

One use of volatile is for a shared but immutable object is recreated on the fly, with many other threads taking a reference to the object at a particular point in their execution cycle. One needs the other threads to begin using the recreated object once it is published, but does not need the additional overhead of full synchronization and it's attendant contention and cache flushing.

// Declaration
public class SharedLocation {
    static public SomeObject someObject=new SomeObject(); // default object

// Publishing code
// Note: do not simply use, since although
//       someObject will be internally consistent for xxx(), a subsequent 
//       call to yyy() might be inconsistent with xxx() if the object was 
//       replaced in between calls.
SharedLocation.someObject=new SomeObject(...); // new object is published

// Using code
private String getError() {
    SomeObject myCopy=SharedLocation.someObject; // gets current copy
    int cod=myCopy.getErrorCode();
    String txt=myCopy.getErrorText();
    return (cod+" - "+txt);
// And so on, with myCopy always in a consistent state within and across calls
// Eventually we will return to the code that gets the current SomeObject.

Speaking to your read-update-write question, specifically. Consider the following unsafe code:

public void updateCounter() {
    if(counter==1000) { counter=0; }
    else              { counter++; }

Now, with the updateCounter() method unsynchronized, two threads may enter it at the same time. Among the many permutations of what could happen, one is that thread-1 does the test for counter==1000 and finds it true and is then suspended. Then thread-2 does the same test and also sees it true and is suspended. Then thread-1 resumes and sets counter to 0. Then thread-2 resumes and again sets counter to 0 because it missed the update from thread-1. This can also happen even if thread switching does not occur as I have described, but simply because two different cached copies of counter were present in two different CPU cores and the threads each ran on a separate core. For that matter, one thread could have counter at one value and the other could have counter at some entirely different value just because of caching.

What's important in this example is that the variable counter was read from main memory into cache, updated in cache and only written back to main memory at some indeterminate point later when a memory barrier occurred or when the cache memory was needed for something else. Making the counter volatile is insufficient for thread-safety of this code, because the test for the maximum and the assignments are discrete operations, including the increment which is a set of non-atomic read+increment+write machine instructions, something like:

MOV EAX,counter
MOV counter,EAX

Volatile variables are useful only when all operations performed on them are "atomic", such as my example where a reference to a fully formed object is only read or written (and, indeed, typically it's only written from a single point). Another example would be a volatile array reference backing a copy-on-write list, provided the array was only read by first taking a local copy of the reference to it.

Remove local git tags that are no longer on the remote repository

How about this - drop all local tags and then re-fetch? Considering your repo might contain submodules:

git submodule foreach --recursive  'git tag | xargs git tag -d'
(alternatively, "for i in `find .git  -type d -name '*tags*'`; do rm -f $i/*;  done")
git fetch -t
git submodule foreach --recursive git fetch -t

How to display a json array in table format?


var obj=[
            id : "001",
            name : "apple",
            category : "fruit",
            color : "red"
            id : "002",
            name : "melon",
            category : "fruit",
            color : "green"
            id : "003",
            name : "banana",
            category : "fruit",
            color : "yellow"
    var tbl=$("<table/>").attr("id","mytable");
    for(var i=0;i<obj.length;i++)
        var tr="<tr>";
        var td1="<td>"+obj[i]["id"]+"</td>";
        var td2="<td>"+obj[i]["name"]+"</td>";
        var td3="<td>"+obj[i]["color"]+"</td></tr>";



PostgreSQL naming conventions

There isn't really a formal manual, because there's no single style or standard.

So long as you understand the rules of identifier naming you can use whatever you like.

In practice, I find it easier to use lower_case_underscore_separated_identifiers because it isn't necessary to "Double Quote" them everywhere to preserve case, spaces, etc.

If you wanted to name your tables and functions "@MyA??! ""betty"" Shard$42" you'd be free to do that, though it'd be pain to type everywhere.

The main things to understand are:

  • Unless double-quoted, identifiers are case-folded to lower-case, so MyTable, MYTABLE and mytable are all the same thing, but "MYTABLE" and "MyTable" are different;

  • Unless double-quoted:

    SQL identifiers and key words must begin with a letter (a-z, but also letters with diacritical marks and non-Latin letters) or an underscore (_). Subsequent characters in an identifier or key word can be letters, underscores, digits (0-9), or dollar signs ($).

  • You must double-quote keywords if you wish to use them as identifiers.

In practice I strongly recommend that you do not use keywords as identifiers. At least avoid reserved words. Just because you can name a table "with" doesn't mean you should.

Get the current fragment object

It might be late but I hope it helps someone else, also @CommonsWare has posted the correct answer.

FragmentManager fm = getSupportFragmentManager();
Fragment fragment_byID = fm.findFragmentById(;
Fragment fragment_byTag = fm.findFragmentByTag("fragment_tag");

Convert UTC date time to local date time

In Angular I used Ben's answer this way:

$scope.convert = function (thedate) {
    var tempstr = thedate.toString();
    var newstr = tempstr.toString().replace(/GMT.*/g, "");
    newstr = newstr + " UTC";
    return new Date(newstr);

Edit: Angular 1.3.0 added UTC support to date filter, I haven't use it yet but it should be easier, here is the format:

{{ date_expression | date : format : timezone}}

Angular 1.4.3 Date API

How to run Gulp tasks sequentially one after the other

Simply make coffee depend on clean, and develop depend on coffee:

gulp.task('coffee', ['clean'], function(){...});
gulp.task('develop', ['coffee'], function(){...});

Dispatch is now serial: cleancoffeedevelop. Note that clean's implementation and coffee's implementation must accept a callback, "so the engine knows when it'll be done":

gulp.task('clean', function(callback){
  del(['dist/*'], callback);

In conclusion, below is a simple gulp pattern for a synchronous clean followed by asynchronous build dependencies:

//build sub-tasks
gulp.task('bar', ['clean'], function(){...});
gulp.task('foo', ['clean'], function(){...});
gulp.task('baz', ['clean'], function(){...});

//main build task
gulp.task('build', ['foo', 'baz', 'bar', ...], function(){...})

Gulp is smart enough to run clean exactly once per build, no matter how many of build's dependencies depend on clean. As written above, clean is a synchronization barrier, then all of build's dependencies run in parallel, then build runs.

jQuery bind to Paste Event, how to get the content of the paste

How about this:

Please use .on if you are using jq1.7 et al.

Behaviour: When you type anything or paste anything on the 1st textarea the teaxtarea below captures the cahnge.

Rest I hope it helps the cause. :)

Helpful link =>

How do you handle oncut, oncopy, and onpaste in jQuery?

Catch paste input


$(document).ready(function() {
    var $editor    = $('#editor');
    var $clipboard = $('<textarea />').insertAfter($editor);

    if(!document.execCommand('StyleWithCSS', false, false)) {
        document.execCommand('UseCSS', false, true);

    $editor.on('paste, keydown', function() {
        var $self = $(this);            
            var $content = $self.html();             

Adding script tag to React/JSX

My favorite way is to use React Helmet – it's a component that allows for easy manipulation of the document head in a way you're probably already used to.


import React from "react";
import {Helmet} from "react-helmet";

class Application extends React.Component {
  render () {
    return (
        <div className="application">
                <script src=""></script>
                <script>try{Typekit.load({ async: true });}catch(e){}</script>

Email validation using jQuery

This regexp prevents duplicate domain names like [email protected], it will allow only domain two time like [email protected]. It also does not allow statring from number like [email protected]

 regexp: /^([a-zA-Z])+([a-zA-Z0-9_.+-])+\@(([a-zA-Z])+\.+?(com|co|in|org|net|edu|info|gov|vekomy))\.?(com|co|in|org|net|edu|info|gov)?$/, 

All The Best !!!!!

How to Update a Component without refreshing full page - Angular

To update component

    export class LoginService{
    private isUserLoggedIn: boolean = false;

    public setLoggedInUser(flag) { // you need set header flag true false from other components on basis of your requirements, header component will be visible as per this flag then
    this.isUserLoggedIn= flag;

public getUserLoggedIn(): boolean {
return this.isUserLoggedIn;

Login Component ts
            Login Component{
             constructor(public service: LoginService){}

public login(){
Inside Header component

 Header Component ts
        HeaderComponent {
         constructor(public service: LoginService){}

         public getUserLoggedIn(): boolean { return this.service.getUserLoggedIn()}

template of header component: Check for user sign in here

<button *ngIf="getUserLoggedIn()">Sign Out</button>
<button *ngIf="!getUserLoggedIn()">Sign In</button>

You can use many approach like show hide using ngIf

App Component ts
AppComponent {
 public showHeader: boolean = true;
App Component html
<div *ngIf='showHeader'> // you show hide on basis of this ngIf and header component always get visible with it's lifecycle hook ngOnInit() called all the time when it get visible

You can also use service

export class AppService {
private showHeader: boolean = false;

public setHeader(flag) { // you need set header flag true false from other components on basis of your requirements, header component will be visible as per this flag then
this.showHeader = flag;

public getHeader(): boolean {
return this.showHeader;

App Component.ts
    AppComponent {
     constructor(public service: AppService){}

App Component.html
    <div *ngIf='service.showHeader'> // you show hide on basis of this ngIf and header component always get visible with it's lifecycle hook ngOnInit() called all the time when it get visible

Making WPF applications look Metro-styled, even in Windows 7? (Window Chrome / Theming / Theme)

Based on Kapitán Mlíko's answer with source above, I would change it to use the following:

Marlett Font Example

It's a better practice to use the Marlett font rather than Path Data points for the Minimize, Restore/Maximize and Close buttons.

<StackPanel Orientation="Horizontal" HorizontalAlignment="Right" VerticalAlignment="Top" WindowChrome.IsHitTestVisibleInChrome="True" Grid.Row="0">
<Button Command="{Binding Source={x:Static SystemCommands.MinimizeWindowCommand}}" ToolTip="minimize" Style="{StaticResource WindowButtonStyle}">
        <Grid Width="30" Height="25">
            <TextBlock Text="0" FontFamily="Marlett" FontSize="14" VerticalAlignment="Center" HorizontalAlignment="Center" Padding="3.5,0,0,3" />
<Grid Margin="1,0,1,0">
    <Button x:Name="Restore" Command="{Binding Source={x:Static SystemCommands.RestoreWindowCommand}}" ToolTip="restore" Visibility="Collapsed" Style="{StaticResource WindowButtonStyle}">
            <Grid Width="30" Height="25" UseLayoutRounding="True">
                <TextBlock Text="2" FontFamily="Marlett" FontSize="14" VerticalAlignment="Center" HorizontalAlignment="Center" Padding="2,0,0,1" />
    <Button x:Name="Maximize" Command="{Binding Source={x:Static SystemCommands.MaximizeWindowCommand}}" ToolTip="maximize" Style="{StaticResource WindowButtonStyle}">
            <Grid Width="31" Height="25">
                <TextBlock Text="1" FontFamily="Marlett" FontSize="14" VerticalAlignment="Center" HorizontalAlignment="Center" Padding="2,0,0,1" />
<Button Command="{Binding Source={x:Static SystemCommands.CloseWindowCommand}}" ToolTip="close"  Style="{StaticResource WindowButtonStyle}">
        <Grid Width="30" Height="25">
            <TextBlock Text="r" FontFamily="Marlett" FontSize="14" VerticalAlignment="Center" HorizontalAlignment="Center" Padding="0,0,0,1" />

Android: how to handle button click

Most used way is, anonymous declaration

    Button send = (Button) findViewById(;
    send.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // handle click

Also you can create View.OnClickListener object and set it to button later, but you still need to override onClick method for example

View.OnClickListener listener = new View.OnClickListener(){
        public void onClick(View v) {
            // handle click
Button send = (Button) findViewById(;

When your activity implements OnClickListener interface you must override onClick(View v) method on activity level. Then you can assing this activity as listener to button, because it already implements interface and overrides the onClick() method

public class MyActivity extends Activity implements View.OnClickListener{

    public void onClick(View v) {
        // handle click

    public void onCreate(Bundle b) {
        Button send = (Button) findViewById(;


(imho) 4-th approach used when multiple buttons have same handler, and you can declare one method in activity class and assign this method to multiple buttons in xml layout, also you can create one method for one button, but in this case I prefer to declare handlers inside activity class.

How do I count the number of occurrences of a char in a String?

String s = "a.b.c.d";
long result = s.chars().filter(ch -> ch == '.').count();

Pass multiple arguments into std::thread

If you're getting this, you may have forgotten to put #include <thread> at the beginning of your file. OP's signature seems like it should work.

Modulo operator in Python

same as a normal modulo 3.14 % 6.28 = 3.14, just like 3.14%4 =3.14 3.14%2 = 1.14 (the remainder...)

CURL and HTTPS, "Cannot resolve host"

If you do it on Windows XAMPP/WAMP it probaly won't work as in my case.

I solved the problem setting up Laravel's Homestead/Vagrant solution to create my (Ubuntu) development environment - it has built-in: Nginx, PHP 5.6, PHP 7.3, PHP 7.2, PHP 7.1, MySQL, PostgreSQL, Redis, Memcached, Node... to name just a few.

See here for info how to set up the environment - it's really worth the effort!

Laravel Homestead is an official, pre-packaged Vagrant box that provides you a wonderful development environment without requiring you to install PHP, a web server, and any other server software on your local machine. No more worrying about messing up your operating system! Vagrant boxes are completely disposable. If something goes wrong, you can destroy and re-create the box in minutes!

Then you can easily switch PHP versions or set up more virtual hosts, new databases just in seconds.

Why do I get "'property cannot be assigned" when sending an SMTP email?

Finally got working :)

using System.Net.Mail;
using System.Text;


// Command line argument must the the SMTP host.
SmtpClient client = new SmtpClient();
client.Port = 587;
client.Host = "";
client.EnableSsl = true;
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("[email protected]","password");

MailMessage mm = new MailMessage("[email protected]", "[email protected]", "test", "test");
mm.BodyEncoding = UTF8Encoding.UTF8;
mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure;


sorry about poor spelling before

Delegation: EventEmitter or Observable in Angular

I found out another solution for this case without using Reactivex neither services. I actually love the rxjx API however I think it goes best when resolving an async and/or complex function. Using It in that way, Its pretty exceeded to me.

What I think you are looking for is for a broadcast. Just that. And I found out this solution:

  <app-nav (selectedTab)="onSelectedTab($event)"></app-nav>
       // This component bellow wants to know when a tab is selected
       // broadcast here is a property of app component
  <app-interested [broadcast]="broadcast"></app-interested>

 @Component class App {
   broadcast: EventEmitter<tab>;

   constructor() {
     this.broadcast = new EventEmitter<tab>();

   onSelectedTab(tab) {

 @Component class AppInterestedComponent implements OnInit {
   broadcast: EventEmitter<Tab>();


   ngOnInit() {
     this.broadcast.subscribe((tab) => this.doSomethingWhenTab(tab))

This is a full working example:

Capturing mobile phone traffic on Wireshark

Install Fiddler on your PC and use it as a proxy on your Android device.


Styling the last td in a table with css

You can use the :last-of-type pseudo-class:

tr > td:last-of-type {
    /* styling here */

See the MDN for more info and compatibility with the different browsers.
Check out the W3C CSS guidelines for more info.

Installing a local module using npm?

So I had a lot of problems with all of the solutions mentioned so far...

I have a local package that I want to always reference (rather than npm link) because it won't be used outside of this project (for now) and also won't be uploaded to an npm repository for wide use as of yet.

I also need it to work on Windows AND Unix, so sym-links aren't ideal.

Pointing to the tar.gz result of (npm package) works for the dependent npm package folder, however this causes issues with the npm cache if you want to update the package. It doesn't always pull in the new one from the referenced npm package when you update it, even if you blow away node_modules and re-do your npm-install for your main project.

so.. This is what worked well for me!

Main Project's Package.json File Snippet:

  "name": "main-project-name",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "preinstall": "cd ../some-npm-package-angular && npm install && npm run build"
  "private": true,
  "dependencies": {
    "@com/some-npm-package-angular": "file:../some-npm-package-angular/dist",

This achieves 3 things:

  • Avoids the common error (at least with angular npm projects) "index.ts is not part of the compilation." - as it points to the built (dist) folder.
  • Adds a preinstall step to build the referenced npm client package to make sure the dist folder of our dependent package is built.
  • Avoids issues where referencing a tar.gz file locally may be cached by npm and not updated in the main project without lots of cleaning/troubleshooting/re-building/re-installing.

I hope this is clear, and helps someone out.

The tar.gz approach also sort of works..

npm install (file path) also sort of works.

This was all based off of a generated client from an openapi spec that we wanted to keep in a separate location (rather than using copy-pasta for individual files)

====== UPDATE: ======

There are additional errors with a regular development flow with the above solution, as npm's versioning scheme with local files is absolutely terrible. If your dependent package changes frequently, this whole scheme breaks because npm will cache your last version of the project and then blow up when the SHA hash doesn't match anymore with what was saved in your package-lock.json file, among other issues.

As a result, I recommend using the *.tgz approach with a version update for each change. This works by doing three things.


For your dependent package, use the npm library "ng-packagr". This is automatically added to auto-generated client packages created by the angular-typescript code generator for OpenAPI 3.0.

As a result the project that I'm referencing has a "scripts" section within package.json that looks like this:

  "scripts": {
    "build": "ng-packagr -p ng-package.json",
    "package": "npm install && npm run build && cd dist && npm pack"

And the project referencing this other project adds a pre-install step to make sure the dependent project is up to date and rebuilt before building itself:

  "scripts": {
    "preinstall": "npm run clean && cd ../some-npm-package-angular && npm run package"


Reference the built tgz npm package from your main project!

  "dependencies": {
    "@com/some-npm-package-angular": "file:../some-npm-package-angular/dist/some-npm-package-angular-<packageVersion>.tgz",


Update the dependent package's version EVERY TIME you update the dependent package. You'll also have to update the version in the main project.

If you do not do this, NPM will choke and use a cached version and explode when the SHA hash doesn't match. NPM versions file-based packages based on the filename changing. It won't check the package itself for an updated version in package.json, and the NPM team stated that they will not fix this, but people keep raising the issue:

for now, just update the:

"version": "1.0.0-build5",

In the dependent package's package.json file, then update your reference to it in the main project to reference the new filename, ex:

"dependencies": {
       "@com/some-npm-package-angular": "file:../some-npm-package-angular/dist/some-npm-package-angular-1.0.0-build5.tgz",

You get used to it. Just update the two package.json files - version then the ref to the new filename.

Hope that helps someone...

C#: Looping through lines of multiline string

I suggest using a combination of StringReader and my LineReader class, which is part of MiscUtil but also available in this StackOverflow answer - you can easily copy just that class into your own utility project. You'd use it like this:

string text = @"First line
second line
third line";

foreach (string line in new LineReader(() => new StringReader(text)))

Looping over all the lines in a body of string data (whether that's a file or whatever) is so common that it shouldn't require the calling code to be testing for null etc :) Having said that, if you do want to do a manual loop, this is the form that I typically prefer over Fredrik's:

using (StringReader reader = new StringReader(input))
    string line;
    while ((line = reader.ReadLine()) != null)
        // Do something with the line

This way you only have to test for nullity once, and you don't have to think about a do/while loop either (which for some reason always takes me more effort to read than a straight while loop).

Matplotlib tight_layout() doesn't take into account figure suptitle

This website has a simple solution to this with an example that worked for me. The line of code that does the actual leaving of space for the title is the following:

plt.tight_layout(rect=[0, 0, 1, 0.95]) 

Here is an image of proof that it worked for me: Image Link

AVD Manager - No system image installed for this target

you should android sdk manager install 4.2 api 17 -> ARM EABI v7a System Image

if not installed ARM EABI v7a System Image, you should install all.

how to fix Cannot call sendRedirect() after the response has been committed?

you have already forwarded the response in catch block:

RequestDispatcher dd = request.getRequestDispatcher("error.jsp");

dd.forward(request, response);

so, you can not again call the :


because it is already forwarded (committed).

So what you can do is: keep a string to assign where you need to forward the response.

    String page = "";
    try {

    } catch (Exception e) {
      page = "error.jsp";
    } finally {
      page = "usertaskpage.jsp";

RequestDispatcher dd=request.getRequestDispatcher(page);
dd.forward(request, response);

Request Permission for Camera and Library in iOS 10 - Info.plist

To ask permission for the photo app you need to add this code (Swift 3):

       (newStatus) in 
         if newStatus ==  PHAuthorizationStatus.authorized { 
          /* do stuff here */ 

How can I pass an argument to a PowerShell script?

    [String] $site,
    [String] $application,
    [String] $dir,
    [String] $applicationPool

# Create Web IIS Application
function ValidateWebSite ([String] $webSiteName)
    $iisWebSite = Get-Website -Name $webSiteName
    if($Null -eq $iisWebSite)
        Write-Error -Message "Error: Web Site Name: $($webSiteName) not exists."  -Category ObjectNotFound
        return 1

# Get full path from IIS WebSite
function GetWebSiteDir ([String] $webSiteName)
    $iisWebSite = Get-Website -Name $webSiteName
    if($Null -eq $iisWebSite)
        Write-Error -Message "Error: Web Site Name: $($webSiteName) not exists."  -Category ObjectNotFound
        return $iisWebSite.PhysicalPath

# Create Directory
function CreateDirectory([string]$fullPath)
    $existEvaluation = Test-Path $fullPath -PathType Any
    if($existEvaluation -eq $false)
        new-item $fullPath -itemtype directory
    return 1

function CreateApplicationWeb
        [String] $WebSite,
        [String] $WebSitePath,
        [String] $application,
        [String] $applicationPath,
        [String] $applicationPool
    $fullDir = "$($WebSitePath)\$($applicationPath)"
    New-WebApplication -Site $WebSite -Name $application -PhysicalPath $fullDir -ApplicationPool $applicationPool -Force

$fullWebSiteDir = GetWebSiteDir($Site)f($null -ne $fullWebSiteDir)
    CreateApplicationWeb -WebSite $Site -WebSitePath $fullWebSiteDir -application $application  -applicationPath $dir -applicationPool $applicationPool

Storing and Retrieving ArrayList values from hashmap

You could try using MultiMap instead of HashMap

Initialising it will require fewer lines of codes. Adding and retrieving the values will also make it shorter.

Map<String, List<Integer>> map = new HashMap<String, List<Integer>>();

would become:

Multimap<String, Integer> multiMap = ArrayListMultimap.create();

You can check this link:

Java ArrayList - how can I tell if two lists are equal, order not mattering?

Apache Commons Collections to the rescue once again:

List<String> listA = Arrays.asList("a", "b", "b", "c");
List<String> listB = Arrays.asList("b", "c", "a", "b");
System.out.println(CollectionUtils.isEqualCollection(listA, listB)); // true


List<String> listC = Arrays.asList("a", "b", "c");
List<String> listD = Arrays.asList("a", "b", "c", "c");
System.out.println(CollectionUtils.isEqualCollection(listC, listD)); // false



public static boolean isEqualCollection(java.util.Collection a,
                                        java.util.Collection b)

Returns true iff the given Collections contain exactly the same elements with exactly the same cardinalities.

That is, iff the cardinality of e in a is equal to the cardinality of e in b, for each element e in a or b.


  • a - the first collection, must not be null
  • b - the second collection, must not be null

Returns: true iff the collections contain the same elements with the same cardinalities.

How to display two digits after decimal point in SQL Server

want to convert the column name Amount as float number with 2 decimals

CASE WHEN EXISTS (SELECT Amount From InvoiceFee Ifee WHERE IFEE.InvoiceId = 
DIR.InvoiceId AND FeeId = 'Freight Cost')
     THEN  CAST ((SELECT Amount From InvoiceFee Ifee WHERE IFEE.InvoiceId = 
DIR.InvoiceId AND FeeId = 'Freight Cost') AS VARCHAR)
            ELSE '' END AS FCost,

How to SHUTDOWN Tomcat in Ubuntu?

For a more graceful way, try the following:

Caveat: I'm running Debian 7, not Ubuntu, though it is a Debian derivative

If you're running Tomcat as a service, you can get a list of all running services by typing:

sudo service --status-all

I'm running Tomcat 7, which is displayed as tomcat7 in said list. Then, to shut it down just type:

sudo service tomcat7 stop

How to set header and options in axios?

There are several ways to do this:

  • For a single request:

    let config = {
      headers: {
        header1: value,
    let data = {
      'HTTP_CONTENT_LANGUAGE': self.language
    }, data, config).then(...)
  • For setting default global config:['header1'] = 'value' // for POST requests
    axios.defaults.headers.common['header1'] = 'value' // for all requests
  • For setting as default on axios instance:

    let instance = axios.create({
      headers: {
        post: {        // can be common or any other method
          header1: 'value1'
    //- or after instance has been created['header1'] = 'value'
    //- or before a request is made
    // using Interceptors
    instance.interceptors.request.use(config => {['header1'] = 'value';
      return config;

MySQL CONCAT returns NULL if any field contain NULL

you can use if statement like below

select CONCAT(if(affiliate_name is null ,'',affiliate_name),'- ',if(model is null ,'',affiliate_name)) as model from devices

error: RPC failed; curl transfer closed with outstanding read data remaining

These steps are working for me:

cd [dir]
git init
git clone [your Repository Url]

I hope that works for you too.

Django TemplateDoesNotExist?

Just a hunch, but check out this article on Django template loading. In particular, make sure you have django.template.loaders.app_directories.Loader in your TEMPLATE_LOADERS list.

ComboBox.SelectedText doesn't give me the SelectedText

I think you want to use

String status = "The status of my combobox is " + comboBoxTest.Text

SelectedText property from MSDN

Gets or sets the text that is selected in the editable portion of a ComboBox.

while Text property from MSDN

Gets or sets the text associated with this control.

Is using 'var' to declare variables optional?

Everything about scope aside, they can be used differently.

console.out(var myObj=1);
//SyntaxError: Unexpected token var

Something something statement vs expression

Stateless vs Stateful

A stateful app is one that stores information about what has happened or changed since it started running. Any public info about what "mode" it is in, or how many records is has processed, or whatever, makes it stateful.

Stateless apps don't expose any of that information. They give the same response to the same request, function or method call, every time. HTTP is stateless in its raw form - if you do a GET to a particular URL, you get (theoretically) the same response every time. The exception of course is when we start adding statefulness on top, e.g. with ASP.NET web apps :) But if you think of a static website with only HTML files and images, you'll know what I mean.

Find distance between two points on map using Google Map API V2

simple util function to calculate distance between two geopoints:

public static long getDistanceMeters(double lat1, double lng1, double lat2, double lng2) {

    double l1 = toRadians(lat1);
    double l2 = toRadians(lat2);
    double g1 = toRadians(lng1);
    double g2 = toRadians(lng2);

    double dist = acos(sin(l1) * sin(l2) + cos(l1) * cos(l2) * cos(g1 - g2));
    if(dist < 0) {
        dist = dist + Math.PI;

    return Math.round(dist * 6378100);

Git reset --hard and push to remote repository

If forcing a push doesn't help ("git push --force origin" or "git push --force origin master" should be enough), it might mean that the remote server is refusing non fast-forward pushes either via receive.denyNonFastForwards config variable (see git config manpage for description), or via update / pre-receive hook.

With older Git you can work around that restriction by deleting "git push origin :master" (see the ':' before branch name) and then re-creating "git push origin master" given branch.

If you can't change this, then the only solution would be instead of rewriting history to create a commit reverting changes in D-E-F:

A-B-C-D-E-F-[(D-E-F)^-1]   master

A-B-C-D-E-F                             origin/master

How to import .py file from another directory?


import importlib.machinery

loader = importlib.machinery.SourceFileLoader('report', '/full/path/report/')
handle = loader.load_module('report')


This method can be used to import whichever way you want in a folder structure (backwards, forwards doesn't really matter, i use absolute paths just to be sure).

There's also the more normal way of importing a python module in Python3,

import importlib
module = importlib.load_module('folder.filename')

Kudos to Sebastian for spplying a similar answer for Python2:

import imp

foo = imp.load_source('', '/path/to/')

How to filter array when object key value is in array

In case you have key value pairs in your input array, I used:

          this.multi_items[0] != null && store.state.isSearchBox === false
            ? item =>
      , "value").includes(item["wijknaam"])
            : item => item["wijknaam"].includes("")

where the input array is multi_items as: [{"text": "bla1", "value": "green"}, {"text": etc. etc.}] is a lodash function.

Swift days between two NSDates

Here is the answer for Swift 3 (tested for IOS 10 Beta)

func daysBetweenDates(startDate: Date, endDate: Date) -> Int
    let calendar = Calendar.current
    let components = calendar.components([.day], from: startDate, to: endDate, options: [])

Then you can call it like this

let pickedDate: Date =
let NumOfDays: Int = daysBetweenDates(startDate: pickedDate, endDate: Date())
    print("Num of Days: \(NumOfDays)")

Private properties in JavaScript ES6 classes

For future reference of other on lookers, I'm hearing now that the recommendation is to use WeakMaps to hold private data.

Here is a more clear, working example:

function storePrivateProperties(a, b, c, d) {
  let privateData = new WeakMap;
  // unique object as key, weak map can only accept object as key, when key is no longer referened, garbage collector claims the key-value 
  let keyA = {}, keyB = {}, keyC = {}, keyD = {};

  privateData.set(keyA, a);
  privateData.set(keyB, b);
  privateData.set(keyC, c);
  privateData.set(keyD, d);

  return {
    logPrivateKey(key) {
      switch(key) {
      case "a":
      case "b":
      case "c":
      case "d":
        console.log(`There is no value for ${key}`)

C++ compile error: has initializer but incomplete type

` Please include either of these:


using std::istringstream; 

Use JavaScript to place cursor at end of text in text input element

Check this solution!

//fn setCurPosition_x000D_
$.fn.setCurPosition = function(pos) {_x000D_
    this.each(function(index, elem) {_x000D_
        if (elem.setSelectionRange) {_x000D_
            elem.setSelectionRange(pos, pos);_x000D_
        } else if (elem.createTextRange) {_x000D_
            var range = elem.createTextRange();_x000D_
            range.moveEnd('character', pos);_x000D_
            range.moveStart('character', pos);_x000D_
    return this;_x000D_
// USAGE - Set Cursor ends_x000D_
// USAGE - Set Cursor at 7 position_x000D_
// $('#str2').setCurPosition(7);
<script src=""></script>_x000D_
<p>Set cursor at any position</p>_x000D_
<p><input type="text" id="str1" value="my string here" /></p>_x000D_
<p><input type="text" id="str2" value="my string here" /></p>

Combine [NgStyle] With Condition (if..else)

The previous answers did not work for me, so I decided to improve this.

You should work with url(''), and not with value.

<li *ngFor="let item of items">
    [ngStyle]="{'background-image': !item.featured ? 'url(\'images/img1.png\')' : 'url(\'images/img2.png\')'}">

What is the use of the @Temporal annotation in Hibernate?

Temporal types are the set of time-based types that can be used in persistent state mappings.

The list of supported temporal types includes the three java.sql types java.sql.Date, java.sql.Time, and java.sql.Timestamp, and it includes the two java.util types java.util.Date and java.util.Calendar.

The java.sql types are completely hassle-free. They act just like any other simple mapping type and do not need any special consideration.

The two java.util types need additional metadata, however, to indicate which of the JDBC java.sql types to use when communicating with the JDBC driver. This is done by annotating them with the @Temporal annotation and specifying the JDBC type as a value of the TemporalType enumerated type.

There are three enumerated values of DATE, TIME, and TIMESTAMP to represent each of the java.sql types.

What is the difference between Forking and Cloning on GitHub?

In a nutshell, Forking is perhaps the same as "cloning under your GitHub ID/profile". A fork is anytime better than a clone, with a few exceptions, obviously. The forked repository is always being monitored/compared with the original repository unlike a cloned repository. That enables you to track the changes, initiate pull requests and also manually sync the changes made in the original repository with your forked one.

How can you create pop up messages in a batch script?

msg * message goes here

That method is very simple and easy and should work in any batch file i believe. The only "downside" to this method is that it can only show 1 message at once, if there is more than one message it will show each one after the other depending on the order you put them inside the code. Also make sure there is a different looping or continuous operator in your batch file or it will close automatically and only this message will appear. If you need a "quiet" background looping opperator, heres one:

pause >nul

That should keep it running but then it will close after a button is pressed.

Also to keep all the commands "quiet" when running, so they just run and dont display that they were typed into the file, just put the following line at the beginning of the batch file:

@echo off

I hope all these tips helped!

blur vs focusout -- any real differences?

As stated in the JQuery documentation

The focusout event is sent to an element when it, or any element inside of it, loses focus. This is distinct from the blur event in that it supports detecting the loss of focus on descendant elements (in other words, it supports event bubbling).

Xcode Debugger: view value of variable

I agree with other posters that Xcode as a developing environment should include an easy way to debug variables. Well, good news, there IS one!

After searching and not finding a simple answer/tutorial on how to debug variables in Xcode I went to explore with Xcode itself and found this (at least for me) very useful discovery.

How to easily debug your variables in Xcode 4.6.3

In the main screen of Xcode make sure to see the bottom Debug Area by clicking the upper-right corner button showed in the screenshot.

Debug Area button

Debug Area in Xcode 4.6.3

Now set a Breakpoint – the line in your code where you want your program to pause, by clicking the border of your Code Area.


Now in the Debug Area look for this buttons and click the one in the middle. You will notice your area is now divided in two.

Split Debug Area

Should look like this

Now run your application.

When the first Breakpoint is reached during the execution of your program you will see on the left side all your variables available at that breakpoint.

Search Field

You can expand the left arrows on the variable for a greater detail. And even use the search field to isolate that variable you want and see it change on real time as you "Step into" the scope of the Breakpoint.

Step Into

On the right side of your Debug Area you can send to print the variables as you desire using the mouse's right-button click over the desired variable.

Contextual Menu

As you can see, that contextual menu is full of very interesting debugging options. Such as Watch that has been already suggested with typed commands or even Edit Value… that changes the runtime value of your variable!

Open Excel file for reading with VBA without display

A much simpler approach that doesn't involve manipulating active windows:

Dim wb As Workbook
Set wb = Workbooks.Open("workbook.xlsx")
wb.Windows(1).Visible = False

From what I can tell the Windows index on the workbook should always be 1. If anyone knows of any race conditions that would make this untrue please let me know.

HttpURLConnection timeout settings

You can set timeout like this,


How to represent matrices in python


Using tuples instead of lists makes it marginally harder to change the data structure in unwanted ways.

If you are going to do extensive use of those, you are best off wrapping a true number array in a class, so you can define methods and properties on them. (Or, you could NumPy, SciPy, ... if you are going to do your processing with those libraries.)

How can I get a count of the total number of digits in a number?

Answers already here work for unsigned integers, but I have not found good solutions for getting number of digits from decimals and doubles.

public static int Length(double number)
    number = Math.Abs(number);
    int length = 1;
    while ((number /= 10) >= 1)
    return length;
//number of digits in 0 = 1,
//number of digits in 22.1 = 2,
//number of digits in -23 = 2

You may change input type from double to decimal if precision matters, but decimal has a limit too.

Parsing JSON array with PHP foreach

You maybe wanted to do the following:

foreach($user->data as $mydata)

         echo $mydata->name . "\n";
         foreach($mydata->values as $values)
              echo $values->value . "\n";

SQL Joins Vs SQL Subqueries (Performance)?

You can use an Explain Plan to get an objective answer.

For your problem, an Exists filter would probably perform the fastest.

How to find a text inside SQL Server procedures / triggers?

Any searching with select statement yield you only object name, where search keyword contains. Easiest and efficient way is get script of procedure/function and then search in generated text file, I also follows this technique :) So you are exact pinpoint.

How to return a specific status code and no contents from Controller?

This code might work for non-.NET Core MVC controllers:

this.HttpContext.Response.StatusCode = 418; // I'm a teapot
return Json(new { status = "mer" }, JsonRequestBehavior.AllowGet);

Converting java date to Sql timestamp

I suggest using DateUtils from apache.commons library.

long millis = DateUtils.truncate(utilDate, Calendar.MILLISECOND).getTime();
java.sql.Timestamp sq = new java.sql.Timestamp(millis );

Edit: Fixed Calendar.MILISECOND to Calendar.MILLISECOND

Python Progress Bar

A very simple approach:

def progbar(count: int) -> None:
    for i in range(count):
        print(f"[{i*'#'}{(count-1-i)*' '}] - {i+1}/{count}", end="\r")
        yield i

And the usage:

from time import sleep

for i in progbar(10):
    sleep(0.2) #whatever task you need to do

Pretty printing XML with javascript

From the text of the question I get the impression that a string result is expected, as opposed to an HTML-formatted result.

If this is so, the simplest way to achieve this is to process the XML document with the identity transformation and with an <xsl:output indent="yes"/> instruction:

<xsl:stylesheet version="1.0"
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

    <xsl:template match="node()|@*">
        <xsl:apply-templates select="node()|@*"/>

When applying this transformation on the provided XML document:


most XSLT processors (.NET XslCompiledTransform, Saxon 6.5.4 and Saxon, AltovaXML) produce the wanted result:

  <node />

How to display hexadecimal numbers in C?


  • 0 - Left-pads the number with zeroes (0) instead of spaces, where padding is specified.
  • 4 (width) - Minimum number of characters to be printed. If the value to be printed is shorter than this number, the result is right justified within this width by padding on the left with the pad character. By default this is a blank space, but the leading zero we used specifies a zero as the pad char. The value is not truncated even if the result is larger.
  • x - Specifier for hexadecimal integer.

More here

How to refresh app upon shaking the device?

I am developing a motion-detection and shake-detection app for my university project.

Besides the original target of the application, I am splitting the library part (responsible for motion and shake detection) from the app. The code is free, available on SourceForge with the project name "BenderCatch". Documentation I am producing will be ready around mid-september.

It uses a more precise way to detect shake: watches BOTH the difference of force between SensorEvents AND the oscillations present in X and Y axis when you perform a shake. It can even make a sound (or vibrate) on each oscillation of the shake.

Feel free to ask me more by e-mail at raffaele [at] terzigno [dot] com

How to implement a confirmation (yes/no) DialogPreference?

That is a simple alert dialog, Federico gave you a site where you can look things up.

Here is a short example of how an alert dialog can be built.

new AlertDialog.Builder(this)
.setMessage("Do you really want to whatever?")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {

    public void onClick(DialogInterface dialog, int whichButton) {
        Toast.makeText(MainActivity.this, "Yaay", Toast.LENGTH_SHORT).show();
 .setNegativeButton(, null).show();

What is key=lambda

In Python, lambda is a keyword used to define anonymous functions(functions with no name) and that's why they are known as lambda functions.

Basically it is used for defining anonymous functions that can/can't take argument(s) and returns value of data/expression. Let's see an example.

>>> # Defining a lambda function that takes 2 parameters(as integer) and returns their sum
>>> lambda num1, num2: num1 + num2 
<function <lambda> at 0x1004b5de8>
>>> # Let's store the returned value in variable & call it(1st way to call)
>>> addition = lambda num1, num2: num1 + num2
>>> addition(62, 5)
>>> addition(1700, 29)
>>> # Let's call it in other way(2nd way to call, one line call )
>>> (lambda num1, num2: num1 + num2)(120, 1)
>>> (lambda num1, num2: num1 + num2)(-68, 2)
>>> (lambda num1, num2: num1 + num2)(-68, 2**3)

Now let me give an answer of your 2nd question. The 1st answer is also great. This is my own way to explain with another example.

Suppose we have a list of items(integers and strings with numeric contents) as follows,

nums = ["2", 1, 3, 4, "5", "8", "-1", "-10"]

and I want to sort it using sorted() function, lets see what happens.

>>> nums = ["2", 1, 3, 4, "5", "8", "-1", "-10"]
>>> sorted(nums)
[1, 3, 4, '-1', '-10', '2', '5', '8']

It didn't give me what I expected as I wanted like below,

['-10', '-1', 1, '2', 3, 4, '5', '8']

It means we need some strategy(so that sorted could treat our string items as an ints) to achieve this. This is why the key keyword argument is used. Please look at the below one.

>>> nums = ["2", 1, 3, 4, "5", "8", "-1", "-10"]
>>> sorted(nums, key=int)
['-10', '-1', 1, '2', 3, 4, '5', '8']

Lets use lambda function as a value of key

>>> names = ["Rishikesh", "aman", "Ajay", "Hemkesh", "sandeep", "Darshan", "Virendra", "Shwetabh"]
>>> names2 = sorted(names)
>>> names2
['Ajay', 'Darshan', 'Hemkesh', 'Rishikesh', 'Shwetabh', 'Virendra', 'aman', 'sandeep']
>>> # But I don't want this o/p(here our intention is to treat 'a' same as 'A')
>>> names3 = sorted(names, key=lambda name:name.lower())
>>> names3
['Ajay', 'aman', 'Darshan', 'Hemkesh', 'Rishikesh', 'sandeep', 'Shwetabh', 'Virendra']

You can define your own function(callable) and provide it as value of key.

Dear programers, I have written the below code for you, just try to understand it and comment your explanation. I would be glad to see your explanation(it's simple).

>>> def validator(item):
...     try:
...         return int(item)
...     except:
...         return 0
>>> sorted(['gurmit', "0", 5, 2, 1, "front", -2, "great"], key=validator)
[-2, 'gurmit', '0', 'front', 'great', 1, 2, 5]

I hope it would be useful.

Oracle - Insert New Row with Auto Incremental ID

ELXAN@DB1> create table cedvel(id integer,ad varchar2(15));

Table created.

ELXAN@DB1> alter table cedvel add constraint pk_ad primary key(id);

Table altered.

ELXAN@DB1> create sequence test_seq start with 1 increment by 1;

Sequence created.

ELXAN@DB1> create or replace trigger ad_insert
before insert on cedvel
for each row
    select test_seq.nextval into from dual;
/  2    3    4    5    6    7    8 

Trigger created.

ELXAN@DB1> insert into cedvel (ad) values ('nese');

1 row created.

Java 8 - Best way to transform a list: map or foreach?

If you use Eclipse Collections you can use the collectIf() method.

MutableList<Integer> source =
    Lists.mutable.with(1, null, 2, null, 3, null, 4, null, 5);

MutableList<String> result = source.collectIf(Objects::nonNull, String::valueOf);

Assert.assertEquals(Lists.immutable.with("1", "2", "3", "4", "5"), result);

It evaluates eagerly and should be a bit faster than using a Stream.

Note: I am a committer for Eclipse Collections.

CMD: How do I recursively remove the "Hidden"-Attribute of files and directories

To make a batch file for its current directory and sub directories:

cd %~dp0
attrib -h -r -s /s /d /l *.*

How to move text up using CSS when nothing is working

try a negative margin.

margin-top: -10px; /* as an example */

Else clause on Python while statement

The else-clause is executed when the while-condition evaluates to false.

From the documentation:

The while statement is used for repeated execution as long as an expression is true:

while_stmt ::=  "while" expression ":" suite
                ["else" ":" suite]

This repeatedly tests the expression and, if it is true, executes the first suite; if the expression is false (which may be the first time it is tested) the suite of the else clause, if present, is executed and the loop terminates.

A break statement executed in the first suite terminates the loop without executing the else clause’s suite. A continue statement executed in the first suite skips the rest of the suite and goes back to testing the expression.

Mongoimport of json file

this will work:

$  mongoimport --db databaseName --collection collectionName --file filePath/jsonFile.json 

2021-01-09T11:13:57.410+0530 connected to: mongodb://localhost/ 2021-01-09T11:13:58.176+0530 1 document(s) imported successfully. 0 document(s) failed to import.

Above I shared the query along with its response

Executing <script> elements inserted with .innerHTML

The OP's script doesn't work in IE 7. With help from SO, here's a script that does:

exec_body_scripts: function(body_el) {
  // Finds and executes scripts in a newly added element's body.
  // Needed since innerHTML does not run scripts.
  // Argument body_el is an element in the dom.

  function nodeName(elem, name) {
    return elem.nodeName && elem.nodeName.toUpperCase() ===

  function evalScript(elem) {
    var data = (elem.text || elem.textContent || elem.innerHTML || "" ),
        head = document.getElementsByTagName("head")[0] ||
        script = document.createElement("script");

    script.type = "text/javascript";
    try {
      // doesn't work on ie...
    } catch(e) {
      // IE has funky script nodes
      script.text = data;

    head.insertBefore(script, head.firstChild);

  // main section of function
  var scripts = [],
      children_nodes = body_el.childNodes,

  for (i = 0; children_nodes[i]; i++) {
    child = children_nodes[i];
    if (nodeName(child, "script" ) &&
      (!child.type || child.type.toLowerCase() === "text/javascript")) {

  for (i = 0; scripts[i]; i++) {
    script = scripts[i];
    if (script.parentNode) {script.parentNode.removeChild(script);}

OpenSSL and error in reading openssl.conf file

  1. first, make sure you have an openssl.cnf file in the right path;
  2. if you can't find it, just download one and copy it to your setting path.

$ set OPENSSL_CONF=C:\OpenSSL\bin\openssl.cnf

jQuery multiple events to trigger the same function

You could define the function that you would like to reuse as below:

var foo = function() {...}

And later you can set however many event listeners you want on your object to trigger that function using on('event') leaving a space in between as shown below:

$('#selector').on('keyup keypress blur change paste cut', foo);

What is a Java String's default initial value?

That depends. Is it just a variable (in a method)? Or a class-member?

If it's just a variable you'll get an error that no value has been set when trying to read from it without first assinging it a value.

If it's a class-member it will be initialized to null by the VM.

What's the difference between :: (double colon) and -> (arrow) in PHP?

Yes, I just hit my first 'PHP Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM'. My bad, I had a $instance::method() that should have been $instance->method(). Silly me.

The odd thing is that this still works just fine on my local machine (running PHP 5.3.8) - nothing, not even a warning with error_reporting = E_ALL - but not at all on the test server, there it just explodes with a syntax error and a white screen in the browser. Since PHP logging was turned off at the test machine, and the hosting company was too busy to turn it on, it was not too obvious.

So, word of warning: apparently, some PHP installations will let you use a $instance::method(), while others don't.

If anybody can expand on why that is, please do.

Writing image to local server

I have an easier solution using fs.readFileSync(./my_local_image_path.jpg)

This is for reading images from Azure Cognative Services's Vision API

const subscriptionKey = 'your_azure_subscrition_key';
const uriBase = // **MUST change your location (mine is 'eastus')**

// Request parameters.
const params = {
    'visualFeatures': 'Categories,Description,Adult,Faces',
    'maxCandidates': '2',
    'details': 'Celebrities,Landmarks',
    'language': 'en'

const options = {
    uri: uriBase,
    qs: params,
    body: fs.readFileSync(./my_local_image_path.jpg),
    headers: {
        'Content-Type': 'application/octet-stream',
        'Ocp-Apim-Subscription-Key' : subscriptionKey
};, (error, response, body) => {
if (error) {
    console.log('Error: ', error);
let jsonString = JSON.stringify(JSON.parse(body), null, '  ');
body = JSON.parse(body);
if (body.code) // err
    console.log("AZURE: " + body.message)

console.log('Response\n' + jsonString);

use a javascript array to fill up a drop down select box

This is a part from a REST-Service I´ve written recently.

var select = $("#productSelect")
for (var prop in data) {
    var option = document.createElement('option');
    option.innerHTML = data[prop].ProduktName
    option.value = data[prop].ProduktName;

The reason why im posting this is because appendChild() wasn´t working in my case so I decided to put up another possibility that works aswell.

Angular 1 - get current URL parameters

To get parameters from URL with ngRoute . It means that you will need to include angular-route.js in your application as a dependency. More information how to do this on official ngRoute documentation.

The solution for the question:

// You need to add 'ngRoute' as a dependency in your app
angular.module('ngApp', ['ngRoute'])
    .config(function ($routeProvider, $locationProvider) {
        // configure the routing rules here
        $routeProvider.when('/backend/:type/:id', {
            controller: 'PagesCtrl'

        // enable HTML5mode to disable hashbang urls
    .controller('PagesCtrl', function ($routeParams) {
        console.log($, $routeParams.type);

If you don't enable the $locationProvider.html5Mode(true);. Urls will use hashbang(/#/).

More information about routing can be found on official angular $route API documentation.

Side note: This question is answering how to achieve this using ng-Route however I would recommend using the ui-Router for routing. It is more flexible, offers more functionality, the documentations is great and it is considered the best routing library for angular.

What are the different NameID format used for?

About this I think you can reference to

Here're my understandings about this, with the Identity Federation Use Case to give a details for those concepts:

  • Persistent identifiers-

IdP provides the Persistent identifiers, they are used for linking to the local accounts in SPs, but they identify as the user profile for the specific service each alone. For example, the persistent identifiers are kind of like : johnForAir, jonhForCar, johnForHotel, they all just for one specified service, since it need to link to its local identity in the service.

  • Transient identifiers-

Transient identifiers are what IdP tell the SP that the users in the session have been granted to access the resource on SP, but the identities of users do not offer to SP actually. For example, The assertion just like “Anonymity(Idp doesn’t tell SP who he is) has the permission to access /resource on SP”. SP got it and let browser to access it, but still don’t know Anonymity' real name.

  • unspecified identifiers-

The explanation for it in the spec is "The interpretation of the content of the element is left to individual implementations". Which means IdP defines the real format for it, and it assumes that SP knows how to parse the format data respond from IdP. For example, IdP gives a format data "UserName=XXXXX Country=US", SP get the assertion, and can parse it and extract the UserName is "XXXXX".

CSS set li indent


or replace 50px with whatever you want.