Programs & Examples On #Python datamodel

Is there a built-in function to print all the current properties and values of an object?

Just try beeprint.

It will help you not only with printing object variables, but beautiful output as well, like this:

  dicts: {
  lists: [],
  static_props: 1,
  tupl: (1, 2)

What are metaclasses in Python?

In addition to the published answers I can say that a metaclass defines the behaviour for a class. So, you can explicitly set your metaclass. Whenever Python gets a keyword class then it starts searching for the metaclass. If it's not found – the default metaclass type is used to create the class's object. Using the __metaclass__ attribute, you can set metaclass of your class:

class MyClass:
   __metaclass__ = type
   # write here other method
   # write here one more method


It'll produce the output like this:

class 'type'

And, of course, you can create your own metaclass to define the behaviour of any class that are created using your class.

For doing that, your default metaclass type class must be inherited as this is the main metaclass:

class MyMetaClass(type):
   __metaclass__ = type
   # you can write here any behaviour you want

class MyTestClass:
   __metaclass__ = MyMetaClass

Obj = MyTestClass()

The output will be:

class '__main__.MyMetaClass'
class 'type'

Getting the class name of an instance?

Do you want the name of the class as a string?


How to get method parameter names?

Here is another way to get the function parameters without using any module.

def get_parameters(func):
    keys = func.__code__.co_varnames[:func.__code__.co_argcount][::-1]
    sorter = {j: i for i, j in enumerate(keys[::-1])} 
    values = func.__defaults__[::-1]
    kwargs = {i: j for i, j in zip(keys, values)}
    sorted_args = tuple(
        sorted([i for i in keys if i not in kwargs], key=sorter.get)
    sorted_kwargs = {
        i: kwargs[i] for i in sorted(kwargs.keys(), key=sorter.get)
    return sorted_args, sorted_kwargs

def f(a, b, c="hello", d="world"): var = a



(('a', 'b'), {'c': 'hello', 'd': 'world'})

c# why can't a nullable int be assigned null as a value

What Harry S says is exactly right, but

int? accom = (accomStr == "noval" ? null : (int?)Convert.ToInt32(accomStr));

would also do the trick. (We Resharper users can always spot each other in crowds...)

How to skip the OPTIONS preflight request?

I think best way is check if request is of type "OPTIONS" return 200 from middle ware. It worked for me.

express.use('*',(req,res,next) =>{
      if (req.method == "OPTIONS") {

Read String line by line

Solution using Java 8 features such as Stream API and Method references

new BufferedReader(new StringReader(myString))


public void someMethod(String myLongString) {

    new BufferedReader(new StringReader(myLongString))

private void parseString(String data) {
    //do something

how to upload a file to my server using html

<form id="uploadbanner" enctype="multipart/form-data" method="post" action="#">
   <input id="fileupload" name="myfile" type="file" />
   <input type="submit" value="submit" id="submit" />

To upload a file, it is essential to set enctype="multipart/form-data" on your form

You need that form type and then some php to process the file :)

You should probably check out Uploadify if you want something very customisable out of the box.

UTC Date/Time String to Timezone

PHP's DateTime object is pretty flexible.

$UTC = new DateTimeZone("UTC");
$newTZ = new DateTimeZone("America/New_York");
$date = new DateTime( "2011-01-01 15:00:00", $UTC );
$date->setTimezone( $newTZ );
echo $date->format('Y-m-d H:i:s');

Exposing the current state name with ui router

Answering your question in this format is quite challenging.

On the other hand you ask about navigation and then about current $state acting all weird.

For the first I'd say it's too broad question and for the second I'd say... well, you are doing something wrong or missing the obvious :)


Take the following controller:

app.controller('MainCtrl', function($scope, $state) {
  $scope.state = $state;

Where app is configured as:

app.config(function($stateProvider) {
    .state('main', {
        url: '/main',
        templateUrl: 'main.html',
        controller: 'MainCtrl'
    .state('main.thiscontent', {
        url: '/thiscontent',
        templateUrl: 'this.html',
        controller: 'ThisCtrl'
    .state('main.thatcontent', {
        url: '/thatcontent',
        templateUrl: 'that.html'

Then simple HTML template having

  {{ state | json }}

Would "print out" e.g. the following

  "params": {}, 
  "current": { 
    "url": "/thatcontent", 
    "templateUrl": "that.html", 
    "name": "main.thatcontent" 
  "transition": null

I put up a small example showing this, using ui.router and pascalprecht.translate for the menus. I hope you find it useful and figure out what is it you are doing wrong.

Plunker here




Unix ls command: show full path when using options

optimized from spacedrop answer ...

ls $(pwd)/*

and you can use ls options

ls -alrt $(pwd)/*

'Property does not exist on type 'never'

Because you are assigning instance to null. The compiler infers that it can never be anything other than null. So it assumes that the else block should never be executed so instance is typed as never in the else block.

Now if you don't declare it as the literal value null, and get it by any other means (ex: let instance: Foo | null = getFoo();), you will see that instance will be null inside the if block and Foo inside the else block.

Never type documentation:


The issue in the updated example is actually an open issue with the compiler. See:

Is there a way I can retrieve sa password in sql server 2005

There is no way to get the old password back. Log into the SQL server management console as a machine or domain admin using integrated authentication, you can then change any password (including sa).

Start the SQL service again and use the new created login (recovery in my example) Go via the security panel to the properties and change the password of the SA account.

enter image description here

Now write down the new SA password.

What's the HTML to have a horizontal space between two objects?

PHP does not do styling. You need to use html or css. Take a look at

In HTML 4.01, the

tag represents a horizontal rule.

In HTML 4.01, the <hr> tag represents a horizontal rule.

Hibernate openSession() vs getCurrentSession()

As explained in this forum post, 1 and 2 are related. If you set hibernate.current_session_context_class to thread and then implement something like a servlet filter that opens the session - then you can access that session anywhere else by using the SessionFactory.getCurrentSession().

SessionFactory.openSession() always opens a new session that you have to close once you are done with the operations. SessionFactory.getCurrentSession() returns a session bound to a context - you don't need to close this.

If you are using Spring or EJBs to manage transactions you can configure them to open / close sessions along with the transactions.

You should never use one session per web app - session is not a thread safe object - cannot be shared by multiple threads. You should always use "one session per request" or "one session per transaction"

Get the _id of inserted document in Mongo database in NodeJS

Mongo sends the complete document as a callbackobject so you can simply get it from there only.

for example,room){
  var newRoomId = room._id;

What does hash do in python?

You can use the Dictionary data type in python. It's very very similar to the hash—and it also supports nesting, similar to the to nested hash.


dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
dict['Age'] = 8; # update existing entry
dict['School'] = "DPS School" # Add new entry

print ("dict['Age']: ", dict['Age'])
print ("dict['School']: ", dict['School'])

For more information, please reference this tutorial on the dictionary data type.

UIWebView open links in Safari

In my case I want to make sure that absolutely everything in the web view opens Safari except the initial load and so I use...

- (BOOL)webView:(UIWebView *)inWeb shouldStartLoadWithRequest:(NSURLRequest *)inRequest navigationType:(UIWebViewNavigationType)inType {
     if(inType != UIWebViewNavigationTypeOther) {
        [[UIApplication sharedApplication] openURL:[inRequest URL]];
        return NO;
     return YES;

Getting an error "fopen': This function or variable may be unsafe." when compling

This is a warning for usual. You can either disable it by

#pragma warning(disable:4996)

or simply use fopen_s like Microsoft has intended.

But be sure to use the pragma before other headers.

Export pictures from excel file into jpg using VBA

Thanks for the ideas! I used the above ideas to make a macro to do a bulk file conversion--convert every file of one format in a folder to another format.

This code requires a sheet with cells named "FilePath" (which must end in a "\"), "StartExt" (original file extension), and "EndExt" (desired file extension). Warning: it doesn't ask for confirmation before replacing existing files with the same name and extension.

Private Sub CommandButton1_Click()
    Dim path As String
    Dim pathExt As String
    Dim file As String
    Dim oldExt As String
    Dim newExt As String
    Dim newFile As String
    Dim shp As Picture
    Dim chrt As ChartObject
    Dim chrtArea As Chart

    Application.ScreenUpdating = False
    Application.DisplayAlerts = False

    'Get settings entered by user
    path = Range("FilePath")
    oldExt = Range("StartExt")
    pathExt = path & "*." & oldExt
    newExt = Range("EndExt")

    file = Dir(pathExt)

    Do While Not file = "" 'cycle through all images in folder of selected format
        Set shp = ActiveSheet.Pictures.Insert(path & file) 'Import image
        newFile = Replace(file, "." & oldExt, "." & newExt) 'Determine new file name
        Set chrt = ActiveSheet.ChartObjects.Add(0, 0, shp.Width, shp.Height) 'Create blank chart for embedding image
        Set chrtArea = chrt.Chart
        shp.CopyPicture 'Copy image to clipboard
        With chrtArea 'Paste image to chart, then export
            .Export (path & newFile)
        End With
        chrt.Delete 'Delete chart
        shp.Delete 'Delete imported image

        file = Dir 'Advance to next file

    Application.ScreenUpdating = True
    Application.DisplayAlerts = True

End Sub

Can I use Objective-C blocks as properties?

Hello, Swift

Complementing what @Francescu answered.

Adding extra parameters:

func test(function:String -> String, param1:String, param2:String) -> String
    return function("test"+param1 + param2)

func funcStyle(s:String) -> String
    return "FUNC__" + s + "__FUNC"
let resultFunc = test(funcStyle, "parameter 1", "parameter 2")

let blockStyle:(String) -> String = {s in return "BLOCK__" + s + "__BLOCK"}
let resultBlock = test(blockStyle, "parameter 1", "parameter 2")

let resultAnon = test({(s:String) -> String in return "ANON_" + s + "__ANON" }, "parameter 1", "parameter 2")


SQL Server Management Studio missing

I know this is an old question, but I've just had the same frustrating issue for a couple of hours and wanted to share my solution. In my case the option "Managements Tools" wasn't available in the installation menu either. It wasn't just greyed out as disabled or already installed, but instead just missing, it wasn't anywhere on the menu.

So what finally worked for me was to use the Web Platform Installer 4.0, and check this for installation: Products > Database > "Sql Server 2008 R2 Management Objects". Once this is done, you can relaunch the installation and "Management Tools" will appear like previous answers stated.

Note there could also be a "Sql Server 2012 Shared Management Objects", but I think this is for different purposes.

Hope this saves someone the couple of hours I wasted into this.

What does the "static" modifier after "import" mean?

the difference between "import static com.showboy.Myclass" and "import com.showboy.Myclass"?

The first should generate a compiler error since the static import only works for importing fields or member types. (assuming MyClass is not an inner class or member from showboy)

I think you meant

import static com.showboy.MyClass.*;

which makes all static fields and members from MyClass available in the actual compilation unit without having to qualify them... as explained above

How do I deal with special characters like \^$.?*|+()[{ in my regex?

I think the easiest way to match the characters like


are using character classes from within R. Consider the following to clean column headers from a data file, which could contain spaces, and punctuation characters:

> library(stringr)
> colnames(order_table) <- str_replace_all(colnames(order_table),"[:punct:]|[:space:]","")

This approach allows us to string character classes to match punctation characters, in addition to whitespace characters, something you would normally have to escape with \\ to detect. You can learn more about the character classes at this cheatsheet below, and you can also type in ?regexp to see more info about this.

How can I tell AngularJS to "refresh"

The solution was to call...

$scope.$apply(); my jQuery event callback.

Escaping single quote in PHP when inserting into MySQL

You should just pass the variable (or data) inside "mysql_real_escape_string(trim($val))"

where $val is the data which is troubling you.

Division of integers in Java

You don't even need doubles for this. Just multiply by 100 first and then divide. Otherwise the result would be less than 1 and get truncated to zero, as you saw.

edit: or if overflow is likely, if it would overflow (ie the dividend is bigger than 922337203685477581), divide the divisor by 100 first.

jQuery/JavaScript: accessing contents of an iframe

I think what you are doing is subject to the same origin policy. This should be the reason why you are getting permission denied type errors.

Padding between ActionBar's home icon and title

I solved this problem by using custom Navigation layout

Using it you can customize anything in title on action bar:


dependencies {
    compile ''


                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />


<style name="ThemeName" parent="Theme.AppCompat.Light">
   <item name="actionBarStyle">@style/ActionBar</item>
   <item name="android:actionBarStyle" tools:ignore="NewApi">@style/ActionBar</item>

<style name="ActionBar" parent="Widget.AppCompat.ActionBar">
   <item name="displayOptions">showCustom</item>
   <item name="android:displayOptions" tools:ignore="NewApi">showCustom</item>

    <item name="customNavigationLayout">@layout/action_bar</item>
   <item name="android:customNavigationLayout" tools:ignore="NewApi">@layout/action_bar</item>

    <item name="background">@color/android:white</item>
   <item name="android:background">@color/android:white</item>


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

Which terminal command to get just IP address and nothing else?

You can also use the following command:

ip route | grep src

NOTE: This will only work if you have connectivity to the internet.

How do I find out if the GPS of an Android device is enabled

In android, we can easily check whether GPS is enabled in device or not using LocationManager.

Here is a simple program to Check.

GPS Enabled or Not :- Add the below user permission line in AndroidManifest.xml to Access Location

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

Your java class file should be

public class ExampleApp extends Activity {
    /** Called when the activity is first created. */
    protected void onCreate(Bundle savedInstanceState) {
        LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
            Toast.makeText(this, "GPS is Enabled in your devide", Toast.LENGTH_SHORT).show();

    private void showGPSDisabledAlertToUser(){
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
        alertDialogBuilder.setMessage("GPS is disabled in your device. Would you like to enable it?")
        .setPositiveButton("Goto Settings Page To Enable GPS",
                new DialogInterface.OnClickListener(){
            public void onClick(DialogInterface dialog, int id){
                Intent callGPSSettingIntent = new Intent(
                new DialogInterface.OnClickListener(){
            public void onClick(DialogInterface dialog, int id){
        AlertDialog alert = alertDialogBuilder.create();;

The output will looks like

enter image description here

enter image description here

Jquery set radio button checked, using id and class selectors

" a class and a div."

I assume when you say "div" you mean "id"? Try this:

$('#test2.test1').prop('checked', true);

No need to muck about with your [attributename=value] style selectors because id has its own format as does class, and they're easily combined although given that id is supposed to be unique it should be enough on its own unless your meaning is "select that element only if it currently has the specified class".

Or more generally to select an input where you want to specify a multiple attribute selector:

$('input:radio[class=test1][id=test2]').prop('checked', true);

That is, list each attribute with its own square brackets.

Note that unless you have a pretty old version of jQuery you should use .prop() rather than .attr() for this purpose.

Tools to search for strings inside files without indexing

Original Answer

Windows Grep does this really well.

Edit: Windows Grep is no longer being maintained or made available by the developer. An alternate download link is here: Windows Grep - alternate

Current Answer

Visual Studio Code has excellent search and replace capabilities across files. It is extremely fast, supports regex and live preview before replacement.

enter image description here

Position buttons next to each other in the center of page

  float: left;
  width: 100%;
  text-align: center;
  position: relative;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
<div class="wrapper">
  <button class="button">Button1</button>
  <button class="button">Button2</button>

Version of Apache installed on a Debian machine

Or, less directly:

nmap -A localhost -p 80

Referencing value in a closed Excel workbook using INDIRECT?

This seems to work with closed file: add a pivot table (rows, tabular layout, no subtotals, no grand totals) of the source to the current workbook, then reference all you want from that pivot table, INDIRECT, LOOKUPs,...

How to make a background 20% transparent on Android

if you want to make color 50% transparent in kotlin,

val percentage = 50f/100 //50%
ColorUtils.setAlphaComponent(resources.getColor(R.color.whatEverColor), (percentage * 255).toInt())

sqlalchemy filter multiple columns

A generic piece of code that will work for multiple columns. This can also be used if there is a need to conditionally implement search functionality in the application.

search_key = "abc"
search_args = [col.ilike('%%%s%%' % search_key) for col in ['col1', 'col2', 'col3']]
query = Query(table).filter(or_(*search_args))

Note: the %% are important to skip % formatting the query.

Populating a ListView using an ArrayList?

public class Example extends Activity
    private ListView lv;
    ArrayList<String> arrlist=new ArrayList<String>();
    //let me assume that you are putting the values in this arraylist
    //Now convert your arraylist to array

    //You will get an exmaple here


    private String arr[]=convert(arrlist);
    public void onCreate(Bundle bun)
        lv.setAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1 , arr));

How to Split Image Into Multiple Pieces in Python

Here is a late answer that works with Python 3

from PIL import Image
import os

def imgcrop(input, xPieces, yPieces):
    filename, file_extension = os.path.splitext(input)
    im =
    imgwidth, imgheight = im.size
    height = imgheight // yPieces
    width = imgwidth // xPieces
    for i in range(0, yPieces):
        for j in range(0, xPieces):
            box = (j * width, i * height, (j + 1) * width, (i + 1) * height)
            a = im.crop(box)
      "images/" + filename + "-" + str(i) + "-" + str(j) + file_extension)


imgcrop("images/testing.jpg", 5, 5)

Then the images will be cropped into pieces according to the specified X and Y pieces, in my case 5 x 5 = 25 pieces

Passing an array/list into a Python function

When you define your function using this syntax:

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

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

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

Then you can call it with this:

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


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

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

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

What does the PHP error message "Notice: Use of undefined constant" mean?

You should quote your array keys:

$department = mysql_real_escape_string($_POST['department']);
$name = mysql_real_escape_string($_POST['name']);
$email = mysql_real_escape_string($_POST['email']);
$message = mysql_real_escape_string($_POST['message']);

As is, it was looking for constants called department, name, email, message, etc. When it doesn't find such a constant, PHP (bizarrely) interprets it as a string ('department', etc). Obviously, this can easily break if you do defined such a constant later (though it's bad style to have lower-case constants).

ImageView rounded corners

Based on Nihal's answer ( ), here is a pure XML version that gives a rectangle with rounded corners on API 24 and above. On below API 24, it will show no rounded corners.




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

        <vector xmlns:android=""
                android:pathData="M0,10 A10,10 0 0,0 10,0 L10,10 Z"

        <vector xmlns:android=""
                android:pathData="M0,0 A10,10 0 0,0 10,10 L0,10 Z"

        <vector xmlns:android=""
                android:pathData="M10,0 A10,10 0 0,0 0,10 L0,0 Z"

        <vector xmlns:android=""
                android:pathData="M10,10 A10,10 0 0,0 0,0 L10,0 Z"


HTTP URL Address Encoding in Java

a solution i developed and much more stable than any other:

public class URLParamEncoder {

    public static String encode(String input) {
        StringBuilder resultStr = new StringBuilder();
        for (char ch : input.toCharArray()) {
            if (isUnsafe(ch)) {
                resultStr.append(toHex(ch / 16));
                resultStr.append(toHex(ch % 16));
            } else {
        return resultStr.toString();

    private static char toHex(int ch) {
        return (char) (ch < 10 ? '0' + ch : 'A' + ch - 10);

    private static boolean isUnsafe(char ch) {
        if (ch > 128 || ch < 0)
            return true;
        return " %$&+,/:;=?@<>#%".indexOf(ch) >= 0;


JSON forEach get Key and Value

Assuming that obj is a pre-constructed object (and not a JSON string), you can achieve this with the following:

   console.log(key + '=' + obj[key]);

Making sure at least one checkbox is checked

if(($("#checkboxid1").is(":checked")) || ($("#checkboxid2").is(":checked"))
            || ($("#checkboxid3").is(":checked"))) {
 //Your Code here

You can use this code to verify that checkbox is checked at least one.


Passing data into "router-outlet" child components

<router-outlet [node]="..."></router-outlet> 

is just invalid. The component added by the router is added as sibling to <router-outlet> and does not replace it.

See also

export class NodeService {
  private node:Subject<Node> = new BehaviorSubject<Node>([]);

  get node$(){
    return this.node.asObservable().filter(node => !!node);

  addNode(data:Node) {;
    selector : 'node-display',
    providers: [NodeService],
    template : `
export class NodeDisplayComponent implements OnInit {
    constructor(private nodeService:NodeService) {}
    node: Node;
    ngOnInit(): void {
                node => {
                err => {
export class ChildDisplay implements OnInit{
    constructor(nodeService:NodeService) {
      nodeService.node$.subscribe(n => this.node = n);

In Eclipse, what can cause Package Explorer "red-x" error-icon when all Java sources compile without errors?

FindBugs also puts a red-x against files/packages to indicate static code analysis errors.

How to export data to an excel file using PHPExcel

If you've copied this directly, then:

->setCellValue('B2', Ackermann') 

should be

->setCellValue('B2', 'Ackermann') 

In answer to your question:

Get the data that you want from limesurvey, and use setCellValue() to store those data values in the cells where you want to store it.

The Quadratic.php example file in /Tests might help as a starting point: it takes data from an input form and sets it to cells in an Excel workbook.


An extremely simplistic example:

// Create your database query
$query = "SELECT * FROM myDataTable";  

// Execute the database query
$result = mysql_query($query) or die(mysql_error());

// Instantiate a new PHPExcel object
$objPHPExcel = new PHPExcel(); 
// Set the active Excel worksheet to sheet 0
// Initialise the Excel row number
$rowCount = 1; 
// Iterate through each result from the SQL query in turn
// We fetch each database result row into $row in turn
while($row = mysql_fetch_array($result)){ 
    // Set cell An to the "name" column from the database (assuming you have a column called name)
    //    where n is the Excel row number (ie cell A1 in the first row)
    $objPHPExcel->getActiveSheet()->SetCellValue('A'.$rowCount, $row['name']); 
    // Set cell Bn to the "age" column from the database (assuming you have a column called age)
    //    where n is the Excel row number (ie cell A1 in the first row)
    $objPHPExcel->getActiveSheet()->SetCellValue('B'.$rowCount, $row['age']); 
    // Increment the Excel row counter

// Instantiate a Writer to create an OfficeOpenXML Excel .xlsx file
$objWriter = new PHPExcel_Writer_Excel2007($objPHPExcel); 
// Write the Excel file to filename some_excel_file.xlsx in the current directory


Using your existing code as the basis

// Instantiate a new PHPExcel object 
$objPHPExcel = new PHPExcel();  
// Set the active Excel worksheet to sheet 0 
// Initialise the Excel row number 
$rowCount = 1;  

//start of printing column names as names of MySQL fields  
$column = 'A';
for ($i = 1; $i < mysql_num_fields($result); $i++)  
    $objPHPExcel->getActiveSheet()->setCellValue($column.$rowCount, mysql_field_name($result,$i));
//end of adding column names  

//start while loop to get data  
$rowCount = 2;  
while($row = mysql_fetch_row($result))  
    $column = 'A';
    for($j=1; $j<mysql_num_fields($result);$j++)  
            $value = NULL;  
        elseif ($row[$j] != "")  
            $value = strip_tags($row[$j]);  
            $value = "";  

        $objPHPExcel->getActiveSheet()->setCellValue($column.$rowCount, $value);

// Redirect output to a client’s web browser (Excel5) 
header('Content-Type: application/'); 
header('Content-Disposition: attachment;filename="Limesurvey_Results.xls"'); 
header('Cache-Control: max-age=0'); 
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5'); 

How do I manage MongoDB connections in a Node.js web application? -> new project -> new cluster -> new collection -> connect -> IP address: & db cred -> connect your application -> copy connection string and paste in .env file of your node app and make sure to replace "" with the actual password for the user and also replace "/test" with your db name

create new file .env

CONNECTIONSTRING=x --> const client = new MongoClient(CONNECTIONSTRING) 

MySql server startup error 'The server quit without updating PID file '

For me the fix was simple:


showed that mysqld was already running

sudo killall mysqld 

then allowed the process to start

jQuery hasClass() - check for more than one class

here's an answer that does follow the syntax of

    $.fn.hasAnyOfClasses = function(){
        for(var i= 0, il=arguments.length; i<il; i++){
            if($self.hasClass(arguments[i])) return true;
        return false;

it's not the fastest, but its unambiguous and the solution i prefer. bench:

How to convert a table to a data frame

Short answer: using, as @Victor Van Hee suggested.

Long answer: may not work on contingency tables generated by table() function, even if is.matrix(your_table) returns TRUE. It will still melt you table into the factor1 factor2 factori counts format.


> freq_t = table(cyl = mtcars$cyl, gear = mtcars$gear)

> freq_t
cyl  3  4  5
  4  1  8  2
  6  2  4  1
  8 12  0  2

> is.matrix(freq_t)
[1] TRUE

  cyl gear Freq
1   4    3    1
2   6    3    2
3   8    3   12
4   4    4    8
5   6    4    4
6   8    4    0
7   4    5    2
8   6    5    1
9   8    5    2
   3 4 5
4  1 8 2
6  2 4 1
8 12 0 2

Sort objects in an array alphabetically on one property of the array

Shorter code with ES6

objArray.sort((a, b) => a.DepartmentName.toLowerCase().localeCompare(b.DepartmentName.toLowerCase()))

@Directive vs @Component in Angular


  1. To register a component we use @Component meta-data annotation.
  2. Component is a directive which uses shadow DOM to create encapsulated visual behavior called components. Components are typically used to create UI widgets.
  3. Component is used to break up the application into smaller components.
  4. Only one component can be present per DOM element.
  5. @View decorator or templateurl template are mandatory in the component.


  1. To register directives we use @Directive meta-data annotation.
  2. Directive is used to add behavior to an existing DOM element.
  3. Directive is use to design re-usable components.
  4. Many directives can be used per DOM element.
  5. Directive doesn't use View.


Printing without newline (print 'a',) prints a space, how to remove?

There are a number of ways of achieving your result. If you're just wanting a solution for your case, use string multiplication as @Ant mentions. This is only going to work if each of your print statements prints the same string. Note that it works for multiplication of any length string (e.g. 'foo' * 20 works).

>>> print 'a' * 20

If you want to do this in general, build up a string and then print it once. This will consume a bit of memory for the string, but only make a single call to print. Note that string concatenation using += is now linear in the size of the string you're concatenating so this will be fast.

>>> for i in xrange(20):
...     s += 'a'
>>> print s

Or you can do it more directly using sys.stdout.write(), which print is a wrapper around. This will write only the raw string you give it, without any formatting. Note that no newline is printed even at the end of the 20 as.

>>> import sys
>>> for i in xrange(20):
...     sys.stdout.write('a')

Python 3 changes the print statement into a print() function, which allows you to set an end parameter. You can use it in >=2.6 by importing from __future__. I'd avoid this in any serious 2.x code though, as it will be a little confusing for those who have never used 3.x. However, it should give you a taste of some of the goodness 3.x brings.

>>> from __future__ import print_function
>>> for i in xrange(20):
...     print('a', end='')

Replacing column values in a pandas DataFrame

I think that in answer should be pointed which type of object do you get in all methods suggested above: is it Series or DataFrame.

When you get column by w.female. or w[[2]] (where, suppose, 2 is number of your column) you'll get back DataFrame. So in this case you can use DataFrame methods like .replace.

When you use .loc or iloc you get back Series, and Series don't have .replace method, so you should use methods like apply, map and so on.

How to clear Flutter's Build cache?

There are basically 3 alternatives to cleaning everything that you could try:

  • flutter clean will delete the /build folder.
  • Manually delete the /build folder, which is essentially the same as flutter clean.
  • Or, as @Rémi Roudsselet pointed out: restart your IDE, as it might be caching some older error logs and locking everything up.

How to upload images into MySQL database using PHP code

Firstly, you should check if your image column is BLOB type!

I don't know anything about your SQL table, but if I'll try to make my own as an example.

We got fields id (int), image (blob) and image_name (varchar(64)).

So the code should look like this (assume ID is always '1' and let's use this mysql_query):

$image = addslashes(file_get_contents($_FILES['image']['tmp_name'])); //SQL Injection defence!
$image_name = addslashes($_FILES['image']['name']);
$sql = "INSERT INTO `product_images` (`id`, `image`, `image_name`) VALUES ('1', '{$image}', '{$image_name}')";
if (!mysql_query($sql)) { // Error handling
    echo "Something went wrong! :("; 

You are doing it wrong in many ways. Don't use mysql functions - they are deprecated! Use PDO or MySQLi. You should also think about storing files locations on disk. Using MySQL for storing images is thought to be Bad Idea™. Handling SQL table with big data like images can be problematic.

Also your HTML form is out of standards. It should look like this:

<form action="insert_product.php" method="POST" enctype="multipart/form-data">
    <label>File: </label><input type="file" name="image" />
    <input type="submit" />


When dealing with files and storing them as a BLOB, the data must be escaped using mysql_real_escape_string(), otherwise it will result in a syntax error.

How to search a list of tuples in Python

[k for k,v in l if v =='delicia']

here l is the list of tuples-[(1,"juca"),(22,"james"),(53,"xuxa"),(44,"delicia")]

And instead of converting it to a dict, we are using llist comprehension.

*Key* in Key,Value in list, where value = **delicia**

Return JsonResult from web api without its properties

return JsonConvert.SerializeObject(images.ToList(), Formatting.None, new JsonSerializerSettings { PreserveReferencesHandling = PreserveReferencesHandling.None, ReferenceLoopHandling = ReferenceLoopHandling.Ignore });

using Newtonsoft.Json;

Iif equivalent in C#

It's limited in that you can't put statements in there. You can only put values(or things that return/evaluate to values), to return

This works ('a' is a static int within class Blah)


(round brackets are impicitly between the equals and the question mark).

This doesn't work.

Blah.a = Blah.a < 4 ? Console.WriteLine("asdf") : Console.WriteLine("34er");
Blah.a = Blah.a < 4 ? MessageBox.Show("asdf") : MessageBox.Show("34er");

So you can only use the c# ternary operator for returning values. So it's not quite like a shortened form of an if. Javascript and perhaps some other languages let you put statements in there.

Get ConnectionString from appsettings.json instead of being hardcoded in .NET Core 2.0 App

  1. Add the following code into startup.cs file.

    public void ConfigureServices(IServiceCollection services)
        string con = Configuration.GetConnectionString("DBConnection");
        GlobalProperties.DBConnection = con;//DBConnection is a user defined static property of GlobalProperties class
  2. Use GlobalProperties.DBConnection property in Context class.

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        if (!optionsBuilder.IsConfigured)

How to install JDBC driver in Eclipse web project without facing java.lang.ClassNotFoundexception

for this error:

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

you need to:

Import java.sql.*;
Import com.mysql.jdbc.Driver;

even if its not used till app running.

SQL JOIN, GROUP BY on three tables to get totals

Thank you very much for the replies!

Saggi Malachi, that query unfortunately sums the invoice amount in cases where there is more than one payment. Say there are two payments to a $39 invoice of $18 and $12. So rather than ending up with a result that looks like:

1   39.00   9.00

You'll end up with:

1   78.00   48.00

Charles Bretana, in the course of trimming my query down to the simplest possible query I (stupidly) omitted an additional table, customerinvoices, which provides a link between customers and invoices. This can be used to see invoices for which payments haven't made.

After much struggling, I think that the following query returns what I need it to:

SELECT DISTINCT i.invoiceid, i.amount, ISNULL(i.amount - p.amount, i.amount) AS amountdue
FROM invoices i
LEFT JOIN invoicepayments ip ON i.invoiceid = ip.invoiceid
LEFT JOIN customerinvoices ci ON i.invoiceid = ci.invoiceid
  SELECT invoiceid, SUM(p.amount) amount
  FROM invoicepayments ip 
  LEFT JOIN payments p ON ip.paymentid = p.paymentid
  GROUP BY ip.invoiceid
) p
ON p.invoiceid = ip.invoiceid
LEFT JOIN payments p2 ON ip.paymentid = p2.paymentid
LEFT JOIN customers c ON ci.customerid = c.customerid
WHERE c.customernumber='100'

Would you guys concur?

How do I use the new computeIfAbsent function?

Another example. When building a complex map of maps, the computeIfAbsent() method is a replacement for map's get() method. Through chaining of computeIfAbsent() calls together, missing containers are constructed on-the-fly by provided lambda expressions:

  // Stores regional movie ratings
  Map<String, Map<Integer, Set<String>>> regionalMovieRatings = new TreeMap<>();

  // This will throw NullPointerException!
  regionalMovieRatings.get("New York").get(5).add("Boyhood");

  // This will work
    .computeIfAbsent("New York", region -> new TreeMap<>())
    .computeIfAbsent(5, rating -> new TreeSet<>())

MySQL Insert query doesn't work with WHERE clause

The simplest way is to use IF to violate your a key constraint. This only works for INSERT IGNORE but will allow you to use constraint in a INSERT.

INSERT INTO Test (id, name) VALUES (IF(1!=0,NULL,1),'Test');

JS regex: replace all digits in string

find the numbers and then replaced with strings which specified. It is achieved by two methods

  1. Using a regular expression literal

  2. Using keyword RegExp object

Using a regular expression literal:

<script type="text/javascript">

var string = "my contact number is 9545554545. my age is 27.";
alert(string.replace(/\d+/g, "XXX"));


**Output:**my contact number is XXX. my age is XXX.

for more details:

Anaconda / Python: Change Anaconda Prompt User Path

Just Type the Drive Location you want to work with: This worked for me! For example you want to change to D drive in windows:


If you want to change to particular folder in the drive:

cd D:\Newfolder

First Heroku deploy failed `error code=H10`

I struggle with the same error for hours, but I was able to solve it. I installed multer and aws-sdk as a devDependencies by mistake, instead of just dependencies. So, anyone who has the same error, just double-check your package.json file.

Also, a small tip for the property of the engine in package.json.

enter code here
//The greater or equal operators will make sure that you use the right node 
//even if your current node is greater version than npm node

"engines": {
"node": ">= 0.8.14"

//insted of
"engines": {
  "node": "0.8.14"

How can I retrieve a table from stored procedure to a datatable?

string connString = "<your connection string>";
string sql = "name of your sp";

using(SqlConnection conn = new SqlConnection(connString)) 
        using(SqlDataAdapter da = new SqlDataAdapter()) 
            da.SelectCommand = new SqlCommand(sql, conn);
            da.SelectCommand.CommandType = CommandType.StoredProcedure;

            DataSet ds = new DataSet();   
            da.Fill(ds, "result_name");

            DataTable dt = ds.Tables["result_name"];

            foreach (DataRow row in dt.Rows) {
                //manipulate your data
    catch(SQLException ex) 
        Console.WriteLine("SQL Error: " + ex.Message);
    catch(Exception e) 
        Console.WriteLine("Error: " + e.Message);

Modified from Java Schools Example

Angular 2 router.navigate

import { ActivatedRoute } from '@angular/router';_x000D_
export class ClassName {_x000D_
  private router = ActivatedRoute;_x000D_
    constructor(r: ActivatedRoute) {_x000D_
        this.router =r;_x000D_
onSuccess() {_x000D_
         {queryParams: {email: loginEmail, code: userCode}});_x000D_
Get this values:_x000D_
ngOnInit() {_x000D_
        .subscribe(params => {_x000D_
            let code = params['code'];_x000D_
            let userEmail = params['email'];_x000D_


Is it possible to set transparency in CSS3 box-shadow?

I suppose rgba() would work here. After all, browser support for both box-shadow and rgba() is roughly the same.

/* 50% black box shadow */
box-shadow: 10px 10px 10px rgba(0, 0, 0, 0.5);

div {_x000D_
    width: 200px;_x000D_
    height: 50px;_x000D_
    line-height: 50px;_x000D_
    text-align: center;_x000D_
    color: white;_x000D_
    background-color: red;_x000D_
    margin: 10px;_x000D_
div.a {_x000D_
  box-shadow: 10px 10px 10px #000;_x000D_
div.b {_x000D_
  box-shadow: 10px 10px 10px rgba(0, 0, 0, 0.5);_x000D_
<div class="a">100% black shadow</div>_x000D_
<div class="b">50% black shadow</div>

Difference between variable declaration syntaxes in Javascript (including global variables)?

In global scope there is no semantic difference.

But you really should avoid a=0 since your setting a value to an undeclared variable.

Also use closures to avoid editing global scope at all

(function() {
   // do stuff locally

   // Hoist something to global scope
   window.someGlobal = someLocal

Always use closures and always hoist to global scope when its absolutely neccesary. You should be using asynchronous event handling for most of your communication anyway.

As @AvianMoncellor mentioned there is an IE bug with var a = foo only declaring a global for file scope. This is an issue with IE's notorious broken interpreter. This bug does sound familiar so it's probably true.

So stick to window.globalName = someLocalpointer

Loop through all the resources in a .resx file

The minute you add a resource .RESX file to your project, Visual Studio will create a Designer.cs with the same name, creating a a class for you with all the items of the resource as static properties. You can see all the names of the resource when you type the dot in the editor after you type the name of the resource file.

Alternatively, you can use reflection to loop through these names.

Type resourceType = Type.GetType("AssemblyName.Resource1");
PropertyInfo[] resourceProps = resourceType.GetProperties(
    BindingFlags.NonPublic | 
    BindingFlags.Static | 

foreach (PropertyInfo info in resourceProps)
    string name = info.Name;
    object value = info.GetValue(null, null);  // object can be an image, a string whatever
    // do something with name and value

This method is obviously only usable when the RESX file is in scope of the current assembly or project. Otherwise, use the method provided by "pulse".

The advantage of this method is that you call the actual properties that have been provided for you, taking into account any localization if you wish. However, it is rather redundant, as normally you should use the type safe direct method of calling the properties of your resources.

Show whitespace characters in Visual Studio Code

I'd like to offer this suggestion as a side note.
If you're looking to fix all the 'trailing whitespaces' warnings your linter throws at you.
You can have VSCode automatically trim whitespaces from an entire file using the keyboard chord.
CTRL+K / X (by default)

I was looking into showing whitespaces because my linter kept bugging me with whitespace warnings. So that's why I'm here.

What tool to use to draw file tree diagram

Copying and pasting from the MS-DOS tree command might also work for you. Examples:


¦   +---BadBaz
¦   +---Drop

tree /F

¦    bar.xml
¦   +---BadBaz
¦   ¦    badbaz.xml
¦   +---Drop

tree /A

C:\Foobar>tree /A
¦   +---BadBaz
¦   \---Drop

tree /F /A

C:\Foobar>tree /A
¦    bar.xml
¦   +---BadBaz
¦   ¦    badbaz.xml
¦   \---Drop

Syntax [source]

tree [drive:][path] [/F] [/A]

drive:\path — Drive and directory containing disk for display of directory structure, without listing files.

/F — Include all files living in every directory.

/A — Replace graphic characters used for linking lines with ext characters , instead of graphic characters. /a is used with code pages that do not support graphic characters and to send output to printers that do not properly interpret graphic characters.

Convert JSON String to Pretty Print JSON output using Jackson

ObjectMapper.readTree() can do this in one line:


Since readTree produces a JsonNode, this should pretty much always produce equivalent pretty-formatted JSON, as it JsonNode is a direct tree representation of the underlying JSON string.

Prior to Jackson 2.10

The JsonNode.toPrettyString() method was added in Jackson 2.10. Prior to that, a second call to the ObjectMapper was needed to write the pretty formatted result:


Formatting doubles for output in C#


Console.WriteLine(String.Format("  {0:G17}", i));

That will give you all the 17 digits it have. By default, a Double value contains 15 decimal digits of precision, although a maximum of 17 digits is maintained internally. {0:R} will not always give you 17 digits, it will give 15 if the number can be represented with that precision.

which returns 15 digits if the number can be represented with that precision or 17 digits if the number can only be represented with maximum precision. There isn't any thing you can to do to make the the double return more digits that is the way it's implemented. If you don't like it do a new double class yourself...

.NET's double cant store any more digits than 17 so you cant see 6.89999999999999946709 in the debugger you would see 6.8999999999999995. Please provide an image to prove us wrong.

How to get parameters from a URL string?

I created function from @Ruel answer. You can use this:

function get_valueFromStringUrl($url , $parameter_name)
    $parts = parse_url($url);
        parse_str($parts['query'], $query);
            return $query[$parameter_name];
            return null;
        return null;


$url = "[email protected]";
echo get_valueFromStringUrl($url , "email");

Thanks to @Ruel

vertical-align: middle doesn't work

Vertical align doesn't quite work the way you want it to. See:

This isn't pretty, but it WILL do what you want: Vertical align behaves as expected only when used in a table cell.

There are other alternatives: You can declare things as tables or table cells within CSS to make them behave as desired, for example. Margins and positioning can sometimes be played with to get the same effect. None of the solutions are terrible pretty, though.

How should I read a file line-by-line in Python?

if you're turned off by the extra line, you can use a wrapper function like so:

def with_iter(iterable):
    with iterable as iter:
        for item in iter:
            yield item

for line in with_iter(open('...')):

in Python 3.3, the yield from statement would make this even shorter:

def with_iter(iterable):
    with iterable as iter:
        yield from iter

jQuery addClass onClick

$(document).ready(function() {
    $('#Button').click(function() {

should do the trick. unless you're loading the button with ajax. In which case you could do:

$('#Button').live('click', function() {...

Also remember not to use the same id more than once in your html code.

Modifying CSS class property values on the fly with JavaScript / jQuery

Demo, IE demo

You could use the following function:

function setStyle(cssText) {
    var sheet = document.createElement('style');
    sheet.type = 'text/css';
    /* Optional */ window.customSheet = sheet;
    (document.head || document.getElementsByTagName('head')[0]).appendChild(sheet);
    return (setStyle = function(cssText, node) {
        if(!node || node.parentNode !== sheet)
            return sheet.appendChild(document.createTextNode(cssText));
        node.nodeValue = cssText;
        return node;


  • The function is written in vanilla-js, so it has better performance than jQuery alternatives
  • One stylesheet is created after the first call to setStyle, so if you don't call it, it won't create any stylesheet.
  • The same stylesheet is reused for the following calls of setStyle
  • The function return a reference to the node associated with the bunch of CSS that you have added. If you call the function again with that node as a second argument, it will replace the old CSS with the new one.


var myCSS = setStyle('*{ color:red; }');
setStyle('*{ color:blue; }', myCSS); // Replaces the previous CSS with this one

Browser support

At least, it works on IE9, FF3, Chrome 1, Safari 4, Opera 10.5.

There's also an IE version which works both on modern browsers and old versions of IE! (Works on IE8 and IE7, but can crash IE6).

Timer Interval 1000 != 1 second?

Any other places you use TimerEventProcessor or Counter?

Anyway, you can not rely on the Event being exactly delivered one per second. The time may vary, and the system will not make sure the average time is correct.

So instead of _Counter, you should use:

 // when starting the timer:
 DateTime _started = DateTime.UtcNow;

 // in TimerEventProcessor:
 seconds = (DateTime.UtcNow-started).TotalSeconds;
 Label.Text = seconds.ToString();

Note: this does not solve the Problem of TimerEventProcessor being called to often, or _Counter incremented to often. it merely masks it, but it is also the right way to do it.

How can I get a value from a map?

How can I get the value from the map, which is passed as a reference to a function?

Well, you can pass it as a reference. The standard reference wrapper that is.

typedef std::map<std::string, std::string> MAP;
// create your map reference type
using map_ref_t = std::reference_wrapper<MAP>;

// use it 
void function(map_ref_t map_r)
    // get to the map from inside the
    // std::reference_wrapper
    // see the alternatives behind that link
    MAP & the_map = map_r;
    // take the value from the map
    // by reference
    auto & value_r = the_map["key"];
    // change it, "in place"
    value_r = "new!";

And the test.

    void test_ref_to_map() {

    MAP valueMap;
    valueMap["key"] = "value";
    // pass it by reference
    // check that the value has changed
    assert( "new!" == valueMap["key"] );

I think this is nice and simple. Enjoy ...

How to use background thread in swift?

From Jameson Quave's tutorial

Swift 2

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
    //All stuff here

How to get first two characters of a string in oracle query?

take a look here

SELECT SUBSTR('Take the first four characters', 1, 4) FIRST_FOUR FROM DUAL;

Call a Subroutine from a different Module in VBA

Prefix the call with Module2 (ex. Module2.IDLE). I'm assuming since you asked this that you have IDLE defined multiple times in the project, otherwise this shouldn't be necessary.

Checking for an empty field with MySQL

This will work but there is still the possibility of a null record being returned. Though you may be setting the email address to a string of length zero when you insert the record, you may still want to handle the case of a NULL email address getting into the system somehow.

     SELECT `userID` 
     FROM `users` 
     WHERE `userID` 
     IN(SELECT `userID`
               FROM `users_indvSettings`
               WHERE `indvSettingID`=5 AND `optionID`='.$time.')
     AND `email` != "" AND `email` IS NOT NULL

how do I use an enum value on a switch statement in C++

Some things to note:

You should always declare your enum inside a namespace as enums are not proper namespaces and you will be tempted to use them like one.

Always have a break at the end of each switch clause execution will continue downwards to the end otherwise.

Always include the default: case in your switch.

Use variables of enum type to hold enum values for clarity.

see here for a discussion of the correct use of enums in C++.

This is what you want to do.

namespace choices
    enum myChoice 
        EASY = 1 ,
        MEDIUM = 2, 
        HARD = 3  

int main(int c, char** argv)
    choices::myChoice enumVar;
    cin >> enumVar;
    switch (enumVar)
        case choices::EASY:
            // do stuff
        case choices::MEDIUM:
            // do stuff

            // is likely to be an error


How to use readline() method in Java?

In summary: I would be careful as to what code you copy. It is possible you are copying code which happens to work, rather than well chosen code.

In intnumber, parseInt is used and in floatnumber valueOf is used why so?

There is no good reason I can see. It's an inconsistent use of the APIs as you suspect.

Java is case sensitive, and there isn't any Readline() method. Perhaps you mean readLine().

DataInputStream.readLine() is deprecated in favour of using BufferedReader.readLine();

However, for your case, I would use the Scanner class.

Scanner sc = new Scanner(;
int intNum = sc.nextInt();
float floatNum = sc.nextFloat();

If you want to know what a class does I suggest you have a quick look at the Javadoc.

Copying text to the clipboard using Java

The following class allows you to copy/paste a String to/from the clipboard.

import java.awt.*;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;

import static java.awt.event.KeyEvent.*;
import static org.apache.commons.lang3.SystemUtils.IS_OS_MAC;

public class SystemClipboard
    public static void copy(String text)
        Clipboard clipboard = getSystemClipboard();
        clipboard.setContents(new StringSelection(text), null);

    public static void paste() throws AWTException
        Robot robot = new Robot();

        int controlKey = IS_OS_MAC ? VK_META : VK_CONTROL;

    public static String get() throws Exception
        Clipboard systemClipboard = getSystemClipboard();
        DataFlavor dataFlavor = DataFlavor.stringFlavor;

        if (systemClipboard.isDataFlavorAvailable(dataFlavor))
            Object text = systemClipboard.getData(dataFlavor);
            return (String) text;

        return null;

    private static Clipboard getSystemClipboard()
        Toolkit defaultToolkit = Toolkit.getDefaultToolkit();
        return defaultToolkit.getSystemClipboard();

Allow multi-line in EditText view in Android?

EditText has singleLine property. You can set in the XML or by calling setSingleLine(false);

@HostBinding and @HostListener: what do they do and what are they for?

Here is a basic hover example.

Component's template property:


<!-- attention, we have the c_highlight class -->
<!-- c_highlight is the selector property value of the directive -->

<p class="c_highlight">
    Some text.

And our directive

import {Component,HostListener,Directive,HostBinding} from '@angular/core';

    // this directive will work only if the DOM el has the c_highlight class
    selector: '.c_highlight'
export class HostDirective {

  // we could pass lots of thing to the HostBinding function. 
  // like class.valid or attr.required etc.

  @HostBinding('style.backgroundColor') c_colorrr = "red"; 

  @HostListener('mouseenter') c_onEnterrr() {
   this.c_colorrr= "blue" ;

  @HostListener('mouseleave') c_onLeaveee() {
   this.c_colorrr = "yellow" ;

geom_smooth() what are the methods available?

Sometimes it's asking the question that makes the answer jump out. The methods and extra arguments are listed on the ggplot2 wiki stat_smooth page.

Which is alluded to on the geom_smooth() page with:

"See stat_smooth for examples of using built in model fitting if you need some more flexible, this example shows you how to plot the fits from any model of your choosing".

It's not the first time I've seen arguments in examples for ggplot graphs that aren't specifically in the function. It does make it tough to work out the scope of each function, or maybe I am yet to stumble upon a magic explicit list that says what will and will not work within each function.

How can I fix assembly version conflicts with JSON.NET after updating NuGet package references in a new ASP.NET MVC 5 project?

I upgraded from Newtonsoft.Json 11.0.1 to 12.0.2. Opening the project file in Notepad++ I discovered both

<Reference Include="Newtonsoft.Json, Version=, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">


    <Reference Include="Newtonsoft.Json">

I deleted the ItemGroup wrapping the reference with the hint path to version 11.0.1.

These issues can be insanely frustrating to find. What's more, developers often follow the same steps as previous project setups. The prior setups didn't encounter the issue. For whatever reason the project file occasionally is updated incorrectly.

I desperately wish Microsoft would fix these visual studio DLL hell issues from popping up. It happens far too often and causing progress to screech to a halt until it is fixed, often by trial and error.

Using Get-childitem to get a list of files modified in the last 3 days

Try this:

(Get-ChildItem -Path c:\pstbak\*.* -Filter *.pst | ? {
  $_.LastWriteTime -gt (Get-Date).AddDays(-3) 

Formatting html email for Outlook

I used VML(Vector Markup Language) based formatting in my email template. In VML Based you have write your code within comment I took help from this site.

Max size of an iOS application

With the release of iOS 7 (September 18th, 2013) apple increased the over-the-air cellular download limit to 100MBs.

Maximum app size remains 2GBs.


Android on-screen keyboard auto popping up

Include this where the imports are on top:

import android.view.WindowManager;

Add this code on OnCreate part:

protected void onCreate(Bundle savedInstanceState) {

How do I compile jrxml to get jasper?

There are three ways to compile jrxml to jasper.

  1. You can do direct compile via compile button (hammer logo) on iReport designer.

  2. You can use ant to compile as shown in the Ant Compile Sample.

    <target name="compile1"> 
      <mkdir dir="./build/reports"/> 
       <classpath refid="runClasspath"/>
       <include name="**/*.jrxml"/>

    Below is the report compile task on my current project.

    alt text

    addition from Daniel Rikowski :

  3. You can also use the JasperCompileManager class to compile from your java code.

                    "our_jasper_template.jrxml", // the path to the jrxml file to compile
                    "our_compiled_template.jasper"); // the path and name we want to save the compiled file to

How to sort multidimensional array by column?

The optional key parameter to sort/sorted is a function. The function is called for each item and the return values determine the ordering of the sort

>>> lst = [['John', 2], ['Jim', 9], ['Jason', 1]]
>>> def my_key_func(item):
...     print("The key for {} is {}".format(item, item[1]))
...     return item[1]
>>> sorted(lst, key=my_key_func)
The key for ['John', 2] is 2
The key for ['Jim', 9] is 9
The key for ['Jason', 1] is 1
[['Jason', 1], ['John', 2], ['Jim', 9]]

taking the print out of the function leaves

>>> def my_key_func(item):
...     return item[1]

This function is simple enough to write "inline" as a lambda function

>>> sorted(lst, key=lambda item: item[1])
[['Jason', 1], ['John', 2], ['Jim', 9]]

Java count occurrence of each item in an array

// An Answer w/o using Hashset or map or Arraylist

public class Count {
    static String names[] = {"name1","name1","name2","name2", "name2"};
    public static void main(String args[]) {



    public static void printCount(String[] names){

        int n = names.length, c;
        for(int i=0;i<n;i++){
            System.out.print(names[i]+" ");
        int result[] = new int[n];
        for(int i=0;i<n;i++){
            result[i] = 0;

        for(int i =0;i<n;i++){
            if (i != n-1){
                for(int j=0;j<n;j++){
                    if(names[i] == names[j] )
            else if (names[n-2] == names[n-1]){
            result[i] = result[i-1];

         else result[i] = 1;
        int max = 0,index = 0;
        for(int i=0;i<n;i++){
         System.out.print(result[i]+"     ");
            if (result[i] >= max){
                max = result[i];
                index = i;


How do I kill a process using Vb.NET or C#?

You'll want to use the System.Diagnostics.Process.Kill method. You can obtain the process you want using System.Diagnostics.Proccess.GetProcessesByName.

Examples have already been posted here, but I found that the non-.exe version worked better, so something like:

foreach ( Process p in System.Diagnostics.Process.GetProcessesByName("winword") )
        p.WaitForExit(); // possibly with a timeout
    catch ( Win32Exception winException )
        // process was terminating or can't be terminated - deal with it
    catch ( InvalidOperationException invalidException )
        // process has already exited - might be able to let this one go

You probably don't have to deal with NotSupportedException, which suggests that the process is remote.

JavaScript: function returning an object

Both styles, with a touch of tweaking, would work.

The first method uses a Javascript Constructor, which like most things has pros and cons.

 // By convention, constructors start with an upper case letter
function MakePerson(name,age) {
  // The magic variable 'this' is set by the Javascript engine and points to a newly created object that is ours. = name;
  this.age = age;
  this.occupation = "Hobo";
var jeremy = new MakePerson("Jeremy", 800);

On the other hand, your other method is called the 'Revealing Closure Pattern' if I recall correctly.

function makePerson(name2, age2) {
  var name = name2;
  var age = age2;

  return {
    name: name,
    age: age

Correct way to use StringBuilder in SQL

The aim of using StringBuilder, i.e reducing memory. Is it achieved?

No, not at all. That code is not using StringBuilder correctly. (I think you've misquoted it, though; surely there aren't quotes around id2 and table?)

Note that the aim (usually) is to reduce memory churn rather than total memory used, to make life a bit easier on the garbage collector.

Will that take memory equal to using String like below?

No, it'll cause more memory churn than just the straight concat you quoted. (Until/unless the JVM optimizer sees that the explicit StringBuilder in the code is unnecessary and optimizes it out, if it can.)

If the author of that code wants to use StringBuilder (there are arguments for, but also against; see note at the end of this answer), better to do it properly (here I'm assuming there aren't actually quotes around id2 and table):

StringBuilder sb = new StringBuilder(some_appropriate_size);
sb.append("select id1, ");
sb.append(" from ");
return sb.toString();

Note that I've listed some_appropriate_size in the StringBuilder constructor, so that it starts out with enough capacity for the full content we're going to append. The default size used if you don't specify one is 16 characters, which is usually too small and results in the StringBuilder having to do reallocations to make itself bigger (IIRC, in the Sun/Oracle JDK, it doubles itself [or more, if it knows it needs more to satisfy a specific append] each time it runs out of room).

You may have heard that string concatenation will use a StringBuilder under the covers if compiled with the Sun/Oracle compiler. This is true, it will use one StringBuilder for the overall expression. But it will use the default constructor, which means in the majority of cases, it will have to do a reallocation. It's easier to read, though. Note that this is not true of a series of concatenations. So for instance, this uses one StringBuilder:

return "prefix " + variable1 + " middle " + variable2 + " end";

It roughly translates to:

StringBuilder tmp = new StringBuilder(); // Using default 16 character size
tmp.append("prefix ");
tmp.append(" middle ");
tmp.append(" end");
return tmp.toString();

So that's okay, although the default constructor and subsequent reallocation(s) isn't ideal, the odds are it's good enough — and the concatenation is a lot more readable.

But that's only for a single expression. Multiple StringBuilders are used for this:

String s;
s = "prefix ";
s += variable1;
s += " middle ";
s += variable2;
s += " end";
return s;

That ends up becoming something like this:

String s;
StringBuilder tmp;
s = "prefix ";
tmp = new StringBuilder();
s = tmp.toString();
tmp = new StringBuilder();
tmp.append(" middle ");
s = tmp.toString();
tmp = new StringBuilder();
s = tmp.toString();
tmp = new StringBuilder();
tmp.append(" end");
s = tmp.toString();
return s;

...which is pretty ugly.

It's important to remember, though, that in all but a very few cases it doesn't matter and going with readability (which enhances maintainability) is preferred barring a specific performance issue.

How to get the index of an element in an IEnumerable?

The way I'm currently doing this is a bit shorter than those already suggested and as far as I can tell gives the desired result:

 var index = haystack.ToList().IndexOf(needle);

It's a bit clunky, but it does the job and is fairly concise.

SQL: How to get the count of each distinct value in a column?

  COUNT(*) AS `num`

How to create custom spinner like border around the spinner with down triangle on the right side?

There are two ways to achieve this.

1- As already proposed u can set the background of your spinner as custom 9 patch Image with all the adjustments made into it .


If you want your Spinner to show With various different background colors i would recommend making the drop down image transparent, & loading that spinner in a relative layout with your color set in.

btn _dropdown is as:

<selector xmlns:android="">
    android:state_window_focused="false" android:state_enabled="true"
    android:drawable="@drawable/spinner_default" />
    android:state_window_focused="false" android:state_enabled="false"
    android:drawable="@drawable/spinner_default" />
    android:drawable="@drawable/spinner_pressed" />
    android:state_focused="true" android:state_enabled="true"
    android:drawable="@drawable/spinner_pressed" />
    android:drawable="@drawable/spinner_default" />
    android:drawable="@drawable/spinner_pressed" />
    android:drawable="@drawable/spinner_default" />

where the various states of pngwould define your various States of spinner seleti

Undefined index error PHP



if (isset($_POST['name'])) {
    $name = $_POST['name'];

if (isset($_POST['price'])) {
    $price = $_POST['price'];

if (isset($_POST['description'])) {
    $description = $_POST['description'];


How to check if a file exists in a shell script

You're missing a required space between the bracket and -e:

if [ -e x.txt ]
    echo "ok"
    echo "nok"

What does a just-in-time (JIT) compiler do?

After the byte code (which is architecture neutral) has been generated by the Java compiler, the execution will be handled by the JVM (in Java). The byte code will be loaded in to JVM by the loader and then each byte instruction is interpreted.

When we need to call a method multiple times, we need to interpret the same code many times and this may take more time than is needed. So we have the JIT (just-in-time) compilers. When the byte has been is loaded in to JVM (its run time), the whole code will be compiled rather than interpreted, thus saving time.

JIT compilers works only during run time, so we do not have any binary output.

How can I parse a JSON file with PHP?

To iterate over a multidimensional array, you can use RecursiveArrayIterator

$jsonIterator = new RecursiveIteratorIterator(
    new RecursiveArrayIterator(json_decode($json, TRUE)),

foreach ($jsonIterator as $key => $val) {
    if(is_array($val)) {
        echo "$key:\n";
    } else {
        echo "$key => $val\n";


status => Wait
status => Active
status => Active
age => 56
count => 10
progress => 0.0029857
bad => 0

run on codepad

IIS 7, HttpHandler and HTTP Error 500.21

This situation happens because you haven't installed/start service of

Use below command in windows 7,8,10.

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

how to increase the limit for max.print in R

Use the options command, e.g. options(max.print=1000000).

See ?options:

 ‘max.print’: integer, defaulting to ‘99999’.  ‘print’ or ‘show’
      methods can make use of this option, to limit the amount of
      information that is printed, to something in the order of
      (and typically slightly less than) ‘max.print’ _entries_.

"Please provide a valid cache path" error in laravel

Your storage directory may be missing, or one of its sub-directories. The storage directory must have all the sub-directories that shipped with the Laravel installation.

Java Enum Methods - return opposite direction enum

Create an abstract method, and have each of your enumeration values override it. Since you know the opposite while you're creating it, there's no need to dynamically generate or create it.

It doesn't read nicely though; perhaps a switch would be more manageable?

public enum Direction {
    NORTH(1) {
        public Direction getOppositeDirection() {
            return Direction.SOUTH;
    SOUTH(-1) {
        public Direction getOppositeDirection() {
            return Direction.NORTH;
    EAST(-2) {
        public Direction getOppositeDirection() {
            return Direction.WEST;
    WEST(2) {
        public Direction getOppositeDirection() {
            return Direction.EAST;

    Direction(int code){
    protected int code;

    public int getCode() {
        return this.code;

    public abstract Direction getOppositeDirection();

Proper way to assert type of variable in Python

You might want to try this example for version 2.6 of Python.

def my_print(text, begin, end):
    "Print text in UPPER between 'begin' and 'end' in lower."
    for obj in (text, begin, end):
        assert isinstance(obj, str), 'Argument of wrong type!'
    print begin.lower() + text.upper() + end.lower()

However, have you considered letting the function fail naturally instead?

Facebook API "This app is in development mode"

I have the same problem while integrating the Facebook SDK for login.

I'm suggesting below approach for development mode > you can test all things if you are login with same account, which is used for '' and if you want to use another accounts then you need to add Roles for that particular app, for that you can add developer or testers by using fid or facebook username.

Eg: - Select the particular app > Roles and then add developer or testers.

enter image description here

Fixed header, footer with scrollable content

As of 2013: This would be my approach. jsFiddle:


<header class="container global-header">
    <h1>Header (fixed)</h1>

<div class="container main-content">
    <div class="inner-w">
        <h1>Main Content</h1>
    </div><!-- .inner-w -->
</div> <!-- .main-content -->

<footer class="container global-footer">
    <h3>Footer (fixed)</h3>


// User reset

* { // creates a natural box model layout
    -moz-box-sizing: border-box; 
    -webkit-box-sizing: border-box; 
    box-sizing: border-box; 
} // asume normalize.css

// structure

.container {
    position: relative;
    width: 100%;
    float: left;
    padding: 1em;

// type

body {
    font-family: arial;   

.main-content {
    h1 {
        font-size: 2em;
        font-weight: bold;
        margin-bottom: .2em;
} // .main-content

// style

    // variables
    $global-header-height: 8em;
    $global-footer-height: 6em;

.global-header {
    position: fixed;
    top: 0; left: 0;
    background-color: gray;
    height: $global-header-height;

.main-content {
    background-color: orange;
    margin-top: $global-header-height;
    margin-bottom: $global-footer-height;
    z-index: -1; // so header will be on top
    min-height: 50em; // to make it long so you can see the scrolling

.global-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    height: $global-footer-height;
    background-color: gray;

Java 8 Iterable.forEach() vs foreach loop

When reading this question one can get the impression, that Iterable#forEach in combination with lambda expressions is a shortcut/replacement for writing a traditional for-each loop. This is simply not true. This code from the OP:

joins.forEach(join -> mIrc.join(mSession, join));

is not intended as a shortcut for writing

for (String join : joins) {
    mIrc.join(mSession, join);

and should certainly not be used in this way. Instead it is intended as a shortcut (although it is not exactly the same) for writing

joins.forEach(new Consumer<T>() {
    public void accept(T join) {
        mIrc.join(mSession, join);

And it is as a replacement for the following Java 7 code:

final Consumer<T> c = new Consumer<T>() {
    public void accept(T join) {
        mIrc.join(mSession, join);
for (T t : joins) {

Replacing the body of a loop with a functional interface, as in the examples above, makes your code more explicit: You are saying that (1) the body of the loop does not affect the surrounding code and control flow, and (2) the body of the loop may be replaced with a different implementation of the function, without affecting the surrounding code. Not being able to access non final variables of the outer scope is not a deficit of functions/lambdas, it is a feature that distinguishes the semantics of Iterable#forEach from the semantics of a traditional for-each loop. Once one gets used to the syntax of Iterable#forEach, it makes the code more readable, because you immediately get this additional information about the code.

Traditional for-each loops will certainly stay good practice (to avoid the overused term "best practice") in Java. But this doesn't mean, that Iterable#forEach should be considered bad practice or bad style. It is always good practice, to use the right tool for doing the job, and this includes mixing traditional for-each loops with Iterable#forEach, where it makes sense.

Since the downsides of Iterable#forEach have already been discussed in this thread, here are some reasons, why you might probably want to use Iterable#forEach:

  • To make your code more explicit: As described above, Iterable#forEach can make your code more explicit and readable in some situations.

  • To make your code more extensible and maintainable: Using a function as the body of a loop allows you to replace this function with different implementations (see Strategy Pattern). You could e.g. easily replace the lambda expression with a method call, that may be overwritten by sub-classes:


    Then you could provide default strategies using an enum, that implements the functional interface. This not only makes your code more extensible, it also increases maintainability because it decouples the loop implementation from the loop declaration.

  • To make your code more debuggable: Seperating the loop implementation from the declaration can also make debugging more easy, because you could have a specialized debug implementation, that prints out debug messages, without the need to clutter your main code with if(DEBUG)System.out.println(). The debug implementation could e.g. be a delegate, that decorates the actual function implementation.

  • To optimize performance-critical code: Contrary to some of the assertions in this thread, Iterable#forEach does already provide better performance than a traditional for-each loop, at least when using ArrayList and running Hotspot in "-client" mode. While this performance boost is small and negligible for most use cases, there are situations, where this extra performance can make a difference. E.g. library maintainers will certainly want to evaluate, if some of their existing loop implementations should be replaced with Iterable#forEach.

    To back this statement up with facts, I have done some micro-benchmarks with Caliper. Here is the test code (latest Caliper from git is needed):

    public class Java8IterationBenchmarks {
        public static class TestObject {
            public int result;
        public @Param({"100", "10000"}) int elementCount;
        ArrayList<TestObject> list;
        TestObject[] array;
        public void setup(){
            list = new ArrayList<>(elementCount);
            for (int i = 0; i < elementCount; i++) {
                list.add(new TestObject());
            array = list.toArray(new TestObject[list.size()]);
        public void timeTraditionalForEach(int reps){
            for (int i = 0; i < reps; i++) {
                for (TestObject t : list) {
        public void timeForEachAnonymousClass(int reps){
            for (int i = 0; i < reps; i++) {
                list.forEach(new Consumer<TestObject>() {
                    public void accept(TestObject t) {
        public void timeForEachLambda(int reps){
            for (int i = 0; i < reps; i++) {
                list.forEach(t -> t.result++);
        public void timeForEachOverArray(int reps){
            for (int i = 0; i < reps; i++) {
                for (TestObject t : array) {

    And here are the results:

    When running with "-client", Iterable#forEach outperforms the traditional for loop over an ArrayList, but is still slower than directly iterating over an array. When running with "-server", the performance of all approaches is about the same.

  • To provide optional support for parallel execution: It has already been said here, that the possibility to execute the functional interface of Iterable#forEach in parallel using streams, is certainly an important aspect. Since Collection#parallelStream() does not guarantee, that the loop is actually executed in parallel, one must consider this an optional feature. By iterating over your list with list.parallelStream().forEach(...);, you explicitly say: This loop supports parallel execution, but it does not depend on it. Again, this is a feature and not a deficit!

    By moving the decision for parallel execution away from your actual loop implementation, you allow optional optimization of your code, without affecting the code itself, which is a good thing. Also, if the default parallel stream implementation does not fit your needs, no one is preventing you from providing your own implementation. You could e.g. provide an optimized collection depending on the underlying operating system, on the size of the collection, on the number of cores, and on some preference settings:

    public abstract class MyOptimizedCollection<E> implements Collection<E>{
        private enum OperatingSystem{
        private OperatingSystem operatingSystem = OperatingSystem.WINDOWS;
        private int numberOfCores = Runtime.getRuntime().availableProcessors();
        private Collection<E> delegate;
        public Stream<E> parallelStream() {
            if (!System.getProperty("parallelSupport").equals("true")) {
            switch (operatingSystem) {
                case WINDOWS:
                    if (numberOfCores > 3 && delegate.size() > 10000) {
                        return this.delegate.parallelStream();
                case LINUX:
                case ANDROID:

    The nice thing here is, that your loop implementation doesn't need to know or care about these details.

Can we pass parameters to a view in SQL?

I realized this task for my needs as follows

set nocount on;

  declare @ToDate date = dateadd(month,datediff(month,0,getdate())-1,0)

declare @year varchar(4)  = year(@ToDate)
declare @month varchar(2) = month(@ToDate)

declare @sql nvarchar(max)
set @sql = N'
    create or alter view dbo.wTempLogs
    select * from dbo.y2019
        year(LogDate) = ''_year_''
        month(LogDate) = ''_month_''    '

select @sql = replace(replace(@sql,'_year_',@year),'_month_',@month)

execute sp_executesql @sql

declare @errmsg nvarchar(max)
    set @errMsg = @sql
    raiserror (@errMsg, 0,1) with nowait

calling server side event from html button control

On your aspx page define the HTML Button element with the usual suspects: runat, class, title, etc.

If this element is part of a data bound control (i.e.: grid view, etc.) you may want to use CommandName and possibly CommandArgument as attributes. Add your button's content and closing tag.

<button id="cmdAction" 
    runat="server" onserverclick="cmdAction_Click()" 
    class="Button Styles" 
    title="Does something on the server" 
    <!-- for databound controls -->
    <!-- content -->
    <span class="ui-icon ..."></span>
    <span class="push">Click Me</span>

On the code behind page the element would call the handler that would be defined as the element's ID_Click event function.

protected void cmdAction_Click(object sender, EventArgs e)
: do something.

There are other solutions as in using custom controls, etc. Also note that I am using this live on projects in VS2K8.

Hoping this helps. Enjoy!

How to draw a circle with given X and Y coordinates as the middle spot of the circle?

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Graphics;
import javax.swing.JFrame;

public class Graphiic
    public Graphics GClass;
    public Graphics2D G2D;
    public  void Draw_Circle(JFrame jf,int radius , int  xLocation, int yLocation)
        GClass = jf.getGraphics();
        GClass.fillArc(xLocation, yLocation, radius, radius, 0, 360);
        GClass.drawLine(100, 100, 200, 200);    


Is there a way to make npm install (the command) to work behind proxy?

when I give without http/http prefix in the proxy settings npm failed even when the proxy host and port were right values. It worked only after adding the protocol prefix.

Spring 3 RequestMapping: Get path value

I have a similar problem and I resolved in this way:

@RequestMapping(value = "{siteCode}/**/{fileName}.{fileExtension}")
public HttpEntity<byte[]> getResource(@PathVariable String siteCode,
        @PathVariable String fileName, @PathVariable String fileExtension,
        HttpServletRequest req, HttpServletResponse response ) throws IOException {
    String fullPath = req.getPathInfo();
    // Calling http://localhost:8080/SiteXX/images/argentine/flag.jpg
    // fullPath conentent: /SiteXX/images/argentine/flag.jpg

Note that req.getPathInfo() will return the complete path (with {siteCode} and {fileName}.{fileExtension}) so you will have to process conveniently.

How to get Database Name from Connection String using SqlConnectionStringBuilder

this gives you the Xact;

System.Data.SqlClient.SqlConnectionStringBuilder connBuilder = new System.Data.SqlClient.SqlConnectionStringBuilder();

connBuilder.ConnectionString = connectionString;

string server = connBuilder.DataSource;           //-> this gives you the Server name.
string database = connBuilder.InitialCatalog;     //-> this gives you the Db name.

Check for column name in a SqlDataReader object

If you read the question, Michael asked about DataReader, not DataRecord folks. Get your objects right.

Using a r.GetSchemaTable().Columns.Contains(field) on a DataRecord does work, but it returns BS columns (see screenshot below.)

To see if a data column exists AND contains data in a DataReader, use the following extensions:

public static class DataReaderExtensions
    /// <summary>
    /// Checks if a column's value is DBNull
    /// </summary>
    /// <param name="dataReader">The data reader</param>
    /// <param name="columnName">The column name</param>
    /// <returns>A bool indicating if the column's value is DBNull</returns>
    public static bool IsDBNull(this IDataReader dataReader, string columnName)
        return dataReader[columnName] == DBNull.Value;

    /// <summary>
    /// Checks if a column exists in a data reader
    /// </summary>
    /// <param name="dataReader">The data reader</param>
    /// <param name="columnName">The column name</param>
    /// <returns>A bool indicating the column exists</returns>
    public static bool ContainsColumn(this IDataReader dataReader, string columnName)
        /// See:
            return dataReader.GetOrdinal(columnName) >= 0;
        catch (IndexOutOfRangeException)
            return false;


    public static bool CanCreate(SqlDataReader dataReader)
        return dataReader.ContainsColumn("RoleTemplateId") 
            && !dataReader.IsDBNull("RoleTemplateId");

Calling r.GetSchemaTable().Columns on a DataReader returns BS columns:

Calling GetSchemeTable in a DataReader

Update Git submodule to latest commit on origin

@Jason is correct in a way but not entirely.


Update the registered submodules, i.e. clone missing submodules and checkout the commit specified in the index of the containing repository. This will make the submodules HEAD be detached unless --rebase or --merge is specified or the key submodule.$name.update is set to rebase or merge.

So, git submodule update does checkout, but it is to the commit in the index of the containing repository. It does not yet know of the new commit upstream at all. So go to your submodule, get the commit you want and commit the updated submodule state in the main repository and then do the git submodule update.

Cannot deserialize the current JSON array (e.g. [1,2,3])

This could be You

Before trying to consume your json object with another object just check that the api is returning raw json via the browser api/rootobject, for my case i found out that the underlying data provider mssqlserver was not running and throw an unhanded exception !

as simple as that :)

Calling javascript function in iframe



to access the Reset function in the iframe

document.getElementById("resultFrame") will get the iframe in your code, and contentWindow will get the window object in the iframe. Once you have the child window, you can refer to javascript in that context.

Also see HERE in particular the answer from bobince.

android studio 0.4.2: Gradle project sync failed error

I found one answer on the net and it worked for me, thus here it is:

When you get the gradle project sync failed error, with error details:

Error occurred during initialization of VM Could not reserve enough space for object heap Error: Could not create the Java Virtual Machine. Error: A fatal exception has occurred. Program will exit.

Then, on Windows, please go to:

Control Panel > System > Advanced(tab) > Environment Variables > System Variables > New:

Variable name _JAVA_OPTIONS and Variable value -Xmx512M

Save it, restart AS. It might work this time, as it did for me.


Best programming based games

There is a Spanish Java Page who organice a football leage in wich the users program the skills of their team and the strategy. You only need to download the framework and implement a little interface, then you can simulate matchs which are seen in the screen. When you are happy with your team and strategy you submit the code to the page and enters in the tournament.

Tutorials, videos and downloads:

Java Cup

Password Protect a SQLite DB. Is it possible?

One option would be VistaDB. They allow databases (or even tables) to be password protected (and optionally encrypted).

Decoding base64 in batch

Actually Windows does have a utility that encodes and decodes base64 - CERTUTIL

I'm not sure what version of Windows introduced this command.

To encode a file:

certutil -encode inputFileName encodedOutputFileName

To decode a file:

certutil -decode encodedInputFileName decodedOutputFileName

There are a number of available verbs and options available to CERTUTIL.

To get a list of nearly all available verbs:

certutil -?

To get help on a particular verb (-encode for example):

certutil -encode -?

To get complete help for nearly all verbs:

certutil -v -?

Mysteriously, the -encodehex verb is not listed with certutil -? or certutil -v -?. But it is described using certutil -encodehex -?. It is another handy function :-)


Regarding David Morales' comment, there is a poorly documented type option to the -encodehex verb that allows creation of base64 strings without header or footer lines.

certutil [Options] -encodehex inFile outFile [type]

A type of 1 will yield base64 without the header or footer lines.

See for a brief listing of the available type formats. And for a more in depth look at the available formats, see

Not investigated, but the -decodehex verb also has an optional trailing type argument.

How can I check if a key exists in a dictionary?

Another method is has_key() (if still using Python 2.X):

>>> a={"1":"one","2":"two"}
>>> a.has_key("1")

JavaScript hide/show element

you can use hidden property of element:


CSS div element - how to show horizontal scroll bars only?

you can also make it overflow: auto and give a maximum fixed height and width that way, when the text or whatever is in there, overflows it'll show only the required scrollbar

How to disable action bar permanently

Go to styles.xml Change this DarkActionBar to NoActionBar

style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

The opposite of Intersect()

I'm not 100% sure what your NonIntersect method is supposed to do (regarding set theory) - is it
B \ A (everything from B that does not occur in A)?
If yes, then you should be able to use the Except operation (B.Except(A)).

Html Agility Pack get all elements by class

You can use the following script:

var findclasses = _doc.DocumentNode.Descendants("div").Where(d => 
    d.Attributes.Contains("class") && d.Attributes["class"].Value.Contains("float")

How to solve WAMP and Skype conflict on Windows 7?

I think it is better to change default port of Skype.

Open skype. Go to Tools, Options, Connections, change the port.

Where to find 64 bit version of chromedriver.exe for Selenium WebDriver?

There is no separate chromedriver binary for Windows 64 bit. Chromedriver 32 bit binary works for both 32 as well as 64 bit versions of Windows. As of today, you can find the latest version of chromedriver Windows binary at

What is a NullReferenceException, and how do I fix it?

The error line "Object reference not set to an instance of an object. " states that you have not assigned instance object to a object reference and still you are accessing properies/methods of that object.

for example: let say you have a class called myClass and it contains one property prop1.

public Class myClass
   public int prop1 {get;set;}

Now you are accessing this prop1 in some other class just like below:

public class Demo
     public void testMethod()
        myClass ref = null;
        ref.prop1 = 1;  //This line throws error

above line throws error because reference of class myClass is declared but not instantiated or an instance of object is not assigned to referecne of that class.

To fix this you have to instantiate (assign object to reference of that class).

public class Demo
     public void testMethod()
        myClass ref = null;
        ref = new myClass();
        ref.prop1 = 1;  

querySelector, wildcard element match?

[id^='someId'] will match all ids starting with someId.

[id$='someId'] will match all ids ending with someId.

[id*='someId'] will match all ids containing someId.

If you're looking for the name attribute just substitute id with name.

If you're talking about the tag name of the element I don't believe there is a way using querySelector

"405 method not allowed" in IIS7.5 for "PUT" method

Often this error is caused by the WebDAV module that try to handle this kind of requests. An easy solution is to remove it from modules and from handlers of the system.webServer section just inside your web.config file. Here a configuration example:

        <remove name="WebDAVModule" />
        <remove name="WebDAV" />

Change drive in git bash for windows

TL;DR; for Windows users:

(Quotation marks not needed if path has no blank spaces)

Git Bash: cd "/C/Program Files (x86)/Android" // macOS/Linux syntax

Cmd.exe: cd "C:\Program Files (x86)\Android" // windows syntax

When using git bash on windows, you have to:

  • remove the colon after the drive letter
  • replace your back-slashes with forward-slashes
  • If you have blank spaces in your path: Put quotation marks at beginning and end of the path

Git Bash: cd "/C/Program Files (x86)/Android" // macOS/Linux syntax

Cmd.exe: cd "C:\Program Files (x86)\Android" // windows syntax

Search and replace part of string in database

update VersionedFields
set Value = replace(replace(value,'<iframe','<a>iframe'), '> </iframe>','</a>')

and you do it in a single pass.

Selecting multiple classes with jQuery

This should work:

$('.myClass, .myOtherClass').removeClass('theclass');

You must add the multiple selectors all in the first argument to $(), otherwise you are giving jQuery a context in which to search, which is not what you want.

It's the same as you would do in CSS.

Parsing a JSON array using Json.Net

You can get at the data values like this:

string json = @"
    { ""General"" : ""At this time we do not have any frequent support requests."" },
    { ""Support"" : ""For support inquires, please see our support page."" }

JArray a = JArray.Parse(json);

foreach (JObject o in a.Children<JObject>())
    foreach (JProperty p in o.Properties())
        string name = p.Name;
        string value = (string)p.Value;
        Console.WriteLine(name + " -- " + value);


How can I change a button's color on hover?

Seems your selector is wrong, try using:

     background: #383;

Your code

a.button a:hover

Means it is going to search for an a element inside a with class button.

How to hide a mobile browser's address bar?

create host file = manifest.json

html tag head

<link rel="manifest" href="/manifest.json">



"name": "news",
"short_name": "news",
"description": "des news application day",
"categories": [
"theme_color": "#ffffff",
"background_color": "#ffffff",
"display": "standalone",
"orientation": "natural",
"lang": "fa",
"dir": "rtl",
"start_url": "/?application=true",
"gcm_sender_id": "482941778795",
"DO_NOT_CHANGE_GCM_SENDER_ID": "Do not change the GCM Sender ID",
"icons": [
"src": "",
"sizes": "192x192",
"type": "image/png"
"src": "",
"sizes": "512x512",
"type": "image/png"
"related_applications": [
"platform": "play",
"url": ""
"prefer_related_applications": true

Specifying java version in maven - differences between properties and compiler plugin

How to specify the JDK version?

Use any of three ways: (1) Spring Boot feature, or use Maven compiler plugin with either (2) source & target or (3) with release.

Spring Boot

  1. <java.version> is not referenced in the Maven documentation.
    It is a Spring Boot specificity.
    It allows to set the source and the target java version with the same version such as this one to specify java 1.8 for both :


Feel free to use it if you use Spring Boot.

maven-compiler-plugin with source & target

  1. Using maven-compiler-plugin or maven.compiler.source/ properties are equivalent.

That is indeed :


is equivalent to :


according to the Maven documentation of the compiler plugin since the <source> and the <target> elements in the compiler configuration use the properties maven.compiler.source and if they are defined.


The -source argument for the Java compiler.
Default value is: 1.6.
User property is: maven.compiler.source.


The -target argument for the Java compiler.
Default value is: 1.6.
User property is:

About the default values for source and target, note that since the 3.8.0 of the maven compiler, the default values have changed from 1.5 to 1.6.

maven-compiler-plugin with release instead of source & target

  1. The maven-compiler-plugin 3.6 and later versions provide a new way :

    org.apache.maven.plugins maven-compiler-plugin 3.8.0 9

You could also declare just :


But at this time it will not work as the maven-compiler-plugin default version you use doesn't rely on a recent enough version.

The Maven release argument conveys release : a new JVM standard option that we could pass from Java 9 :

Compiles against the public, supported and documented API for a specific VM version.

This way provides a standard way to specify the same version for the source, the target and the bootstrap JVM options.
Note that specifying the bootstrap is a good practice for cross compilations and it will not hurt if you don't make cross compilations either.

Which is the best way to specify the JDK version?

The first way (<java.version>) is allowed only if you use Spring Boot.

For Java 8 and below :

About the two other ways : valuing the maven.compiler.source/ properties or using the maven-compiler-plugin, you can use one or the other. It changes nothing in the facts since finally the two solutions rely on the same properties and the same mechanism : the maven core compiler plugin.

Well, if you don't need to specify other properties or behavior than Java versions in the compiler plugin, using this way makes more sense as this is more concise:


From Java 9 :

The release argument (third point) is a way to strongly consider if you want to use the same version for the source and the target.

What happens if the version differs between the JDK in JAVA_HOME and which one specified in the pom.xml?

It is not a problem if the JDK referenced by the JAVA_HOME is compatible with the version specified in the pom but to ensure a better cross-compilation compatibility think about adding the bootstrap JVM option with as value the path of the rt.jar of the target version.

An important thing to consider is that the source and the target version in the Maven configuration should not be superior to the JDK version referenced by the JAVA_HOME.
A older version of the JDK cannot compile with a more recent version since it doesn't know its specification.

To get information about the source, target and release supported versions according to the used JDK, please refer to java compilation : source, target and release supported versions.

How handle the case of JDK referenced by the JAVA_HOME is not compatible with the java target and/or source versions specified in the pom?

For example, if your JAVA_HOME refers to a JDK 1.7 and you specify a JDK 1.8 as source and target in the compiler configuration of your pom.xml, it will be a problem because as explained, the JDK 1.7 doesn't know how to compile with.
From its point of view, it is an unknown JDK version since it was released after it.
In this case, you should configure the Maven compiler plugin to specify the JDK in this way :


You could have more details in examples with maven compiler plugin.

It is not asked but cases where that may be more complicated is when you specify source but not target. It may use a different version in target according to the source version. Rules are particular : you can read about them in the Cross-Compilation Options part.

Why the compiler plugin is traced in the output at the execution of the Maven package goal even if you don't specify it in the pom.xml?

To compile your code and more generally to perform all tasks required for a maven goal, Maven needs tools. So, it uses core Maven plugins (you recognize a core Maven plugin by its groupId : org.apache.maven.plugins) to do the required tasks : compiler plugin for compiling classes, test plugin for executing tests, and so for... So, even if you don't declare these plugins, they are bound to the execution of the Maven lifecycle.
At the root dir of your Maven project, you can run the command : mvn help:effective-pom to get the final pom effectively used. You could see among other information, attached plugins by Maven (specified or not in your pom.xml), with the used version, their configuration and the executed goals for each phase of the lifecycle.

In the output of the mvn help:effective-pom command, you could see the declaration of these core plugins in the <build><plugins> element, for example :


You can have more information about it in the introduction of the Maven lifeycle in the Maven documentation.

Nevertheless, you can declare these plugins when you want to configure them with other values as default values (for example, you did it when you declared the maven-compiler plugin in your pom.xml to adjust the JDK version to use) or when you want to add some plugin executions not used by default in the Maven lifecycle.

Python SQL query string formatting

To avoid formatting entirely, I think a great solution is to use procedures.

Calling a procedure gives you the result of whatever query you want to put in this procedure. You can actually process multiple queries within a procedure. The call will just return the last query that was called.


   SELECT 2+222+2222+222+222+2222+2222 AS this_is_a_really_long_string_test;
   END //

#calling the procedure gives you the result of whatever query you want to put in this procedure. You can actually process multiple queries within a procedure. The call just returns the last query result
 call example;


sql =('call example;')

Get underlined text with Markdown

Both <ins>text</ins> and <span style="text-decoration:underline">text</span> work perfectly in Joplin, although I agree with @nfm that underlined text looks like a link and can be misleading in Markdown.

Better way to right align text in HTML Table

To answer your question directly: no. There is no more simple way to get a consistent look and feel across all modern browsers, without repeating the class on the column. (Although, see below re: nth-child.)

The following is the most efficient way to do this.


<table class="products">
    <td class="price">10.00</td>
    <td class="price">11.45</td>


table.products td.price {
  text-align: right;

nth-child is now supported by 96% of the browsers, what is below is now 11 years old!

Why you shouldn't use nth-child:

The CSS3 pseudo-selector, nth-child, would be perfect for this -- and much more efficient -- but it is impractical for use on the actual web as it exists today. It is not supported by several major modern browsers, including all IE's from 6-8. Unfortunately, this means that nth-child is unsupported in a significant share (at least 40%) of browsers today.

So, nth-child is awesome, but if you want a consistent look and feel, it's just not feasible to use.

Add new attribute (element) to JSON object using JavaScript

A JSON object is simply a javascript object, so with Javascript being a prototype based language, all you have to do is address it using the dot notation.

mything.NewField = 'foo';

Counting number of occurrences in column?

Just adding some extra sorting if needed

=QUERY(A2:A,"select A, count(A) where A is not null group by A order by count(A) DESC label A 'Name', count(A) 'Count'",-1)

enter image description here

Python script to do something at the same time every day

I needed something similar for a task. This is the code I wrote: It calculates the next day and changes the time to whatever is required and finds seconds between currentTime and next scheduled time.

import datetime as dt

def my_job():
    print "hello world"
nextDay = + dt.timedelta(days=1)
dateString = nextDay.strftime('%d-%m-%Y') + " 01-00-00"
newDate = nextDay.strptime(dateString,'%d-%m-%Y %H-%M-%S')
delay = (newDate -

Bad Gateway 502 error with Apache mod_proxy and Tomcat

I'm guessing your using mod_proxy_http (or proxy balancer).

Look in your tomcat logs (localhost.log, or catalina.log) I suspect your seeing an exception in your web stack bubbling up and closing the socket that the tomcat worker is connected to.

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

In terms of how this is implemented, this changes the method - from OrderBy/ThenBy to OrderByDescending/ThenByDescending. However, you can apply the sort separately to the main query...

var qry = from .... // or just dataList.AsEnumerable()/AsQueryable()

if(sortAscending) {
    qry = qry.OrderBy(x=>x.Property);
} else {
    qry = qry.OrderByDescending(x=>x.Property);

Any use? You can create the entire "order" dynamically, but it is more involved...

Another trick (mainly appropriate to LINQ-to-Objects) is to use a multiplier, of -1/1. This is only really useful for numeric data, but is a cheeky way of achieving the same outcome.

How can change width of dropdown list?

Try this code:

<select name="wgtmsr" id="wgtmsr">
<option value="kg">Kg</option>
<option value="gm">Gm</option>
<option value="pound">Pound</option>
<option value="MetricTon">Metric ton</option>
<option value="litre">Litre</option>
<option value="ounce">Ounce</option>



If you want to change the width of the option you can do this in your css:

#wgtmsr option{

Maybe you have a conflict in your css rules that override the width of your select


In Java, can you modify a List while iterating through it?

There is nothing wrong with the idea of modifying an element inside a list while traversing it (don't modify the list itself, that's not recommended), but it can be better expressed like this:

for (int i = 0; i < letters.size(); i++) {
    letters.set(i, "D");

At the end the whole list will have the letter "D" as its content. It's not a good idea to use an enhanced for loop in this case, you're not using the iteration variable for anything, and besides you can't modify the list's contents using the iteration variable.

Notice that the above snippet is not modifying the list's structure - meaning: no elements are added or removed and the lists' size remains constant. Simply replacing one element by another doesn't count as a structural modification. Here's the link to the documentation quoted by @ZouZou in the comments, it states that:

A structural modification is any operation that adds or deletes one or more elements, or explicitly resizes the backing array; merely setting the value of an element is not a structural modification

Can typescript export a function?

To answer the title of your question directly because this comes up in Google first:

YES, TypeScript can export a function!

Here is a direct quote from the TS Documentation:

"Any declaration (such as a variable, function, class, type alias, or interface) can be exported by adding the export keyword."

Reference Link

How to initialize a vector in C++

With the new C++ standard (may need special flags to be enabled on your compiler) you can simply do:

std::vector<int> v { 34,23 };
// or
// std::vector<int> v = { 34,23 };

Or even:

std::vector<int> v(2);
v = { 34,23 };

On compilers that don't support this feature (initializer lists) yet you can emulate this with an array:

int vv[2] = { 12,43 };
std::vector<int> v(&vv[0], &vv[0]+2);

Or, for the case of assignment to an existing vector:

int vv[2] = { 12,43 };
v.assign(&vv[0], &vv[0]+2);

Like James Kanze suggested, it's more robust to have functions that give you the beginning and end of an array:

template <typename T, size_t N>
T* begin(T(&arr)[N]) { return &arr[0]; }
template <typename T, size_t N>
T* end(T(&arr)[N]) { return &arr[0]+N; }

And then you can do this without having to repeat the size all over:

int vv[] = { 12,43 };
std::vector<int> v(begin(vv), end(vv));

Subscript out of bounds - general definition and solution?

If this helps anybody, I encountered this while using purr::map() with a function I wrote which was something like this:

find_nearby_shops <- function(base_account) {
   states_table %>% 
        filter(state == base_account$state) %>% 
        left_join(target_locations, by = c('border_states' = 'state')) %>% 
        mutate(x_latitude = base_account$latitude,
               x_longitude = base_account$longitude) %>% 
        mutate(dist_miles = geosphere::distHaversine(p1 = cbind(longitude, latitude), 
                                                     p2 = cbind(x_longitude, x_latitude))/1609.344)

nearby_shop_numbers <- base_locations %>% 
    split(f = base_locations$id) %>% 

I would get this error sometimes with samples, but most times I wouldn't. The root of the problem is that some of the states in the base_locations table (PR) did not exist in the states_table, so essentially I had filtered out everything, and passed an empty table on to mutate. The moral of the story is that you may have a data issue and not (just) a code problem (so you may need to clean your data.)

Thanks for agstudy and zx8754's answers above for helping with the debug.

What are callee and caller saved registers?

Caller-Saved (AKA volatile or call-clobbered) Registers

  • The values in caller-saved registers are short term and are not preserved from call to call  
  • It holds temporary (i.e. short term) data

Callee-Saved (AKA non-volatile or call-preserved) Registers

  • The callee-saved registers hold values across calls and are long term
  • It holds non-temporary (i.e. long term) data that is used through multiple functions/calls

How can I write a heredoc to a file in Bash script?

When root permissions are required

When root permissions are required for the destination file, use |sudo tee instead of >:

cat << 'EOF' |sudo tee /tmp/yourprotectedfilehere
The variable $FOO will *not* be interpreted.

cat << "EOF" |sudo tee /tmp/yourprotectedfilehere
The variable $FOO *will* be interpreted.

How to capitalize the first letter of a String in Java?

Use this utility method to get all first letter in capital.

String captializeAllFirstLetter(String name) 
    char[] array = name.toCharArray();
    array[0] = Character.toUpperCase(array[0]);

    for (int i = 1; i < array.length; i++) {
        if (Character.isWhitespace(array[i - 1])) {
            array[i] = Character.toUpperCase(array[i]);

    return new String(array);

issue ORA-00001: unique constraint violated coming in INSERT/UPDATE

This ORA error is occurred because of violation of unique constraint.

ORA-00001: unique constraint (constraint_name) violated

This is caused because of trying to execute an INSERT or UPDATE statement that has created a duplicate value in a field restricted by a unique index.

You can resolve this either by

  • changing the constraint to allow duplicates, or
  • drop the unique constraint or you can change your SQL to avoid duplicate inserts

passing several arguments to FUN of lapply (and others *apply)

As suggested by Alan, function 'mapply' applies a function to multiple Multiple Lists or Vector Arguments:

mapply(myfun, arg1, arg2)

See man page:

Broadcast receiver for checking internet connection in android app

I know this thread is old and fully answered but I feel that the following might help some people.

The code in the body of the question contains a bug which no one here addressed. @Nikhil is checking whether the wifi/mobile is available and not if it's connected.

The fix is here:

public void onReceive(final Context context, final Intent intent) {
    final ConnectivityManager connMgr = (ConnectivityManager) context

    final wifi = connMgr

    final mobile = connMgr

    if (wifi.isConnected() || mobile.isConnected()) {
      // do stuff

Verify ImageMagick installation

This is as short and sweet as it can get:

if (!extension_loaded('imagick'))
    echo 'imagick not installed';

Unicode via CSS :before

In CSS, FontAwesome unicode works only when the correct font family is declared (version 4 or less):

font-family: "FontAwesome";
content: "\f066";

Update - Version 5 has different names:


font-family: "Font Awesome 5 Free"


font-family: "Font Awesome 5 Pro"


font-family: "Font Awesome 5 Brands"

See this related answer:

As per comment (BuddyZ) some more info here

Clearing Magento Log Data

You may check good article here:

It has instructions how to check database size, truncate some tables and how to configure automatic table cleaning.

jQuery set checkbox checked

Worked for me:

$checkbok.prop({checked: true});

Java: convert List<String> to a String

Java 8 does bring the

Collectors.joining(CharSequence delimiter, CharSequence prefix, CharSequence suffix)

method, that is nullsafe by using prefix + suffix for null values.

It can be used in the following manner:

String s =" and ", "prefix_", "_suffix"))

The Collectors.joining(CharSequence delimiter) method just calls joining(delimiter, "", "") internally.

PHP: Update multiple MySQL fields in single query

Comma separate the values:

UPDATE settings SET postsPerPage = $postsPerPage, style = $style WHERE id = '1'"

Finding modified date of a file/folder

PowerShell code to find all document library files modified from last 2 days.

$web = Get-SPWeb -Identity http://siteName:9090/ 
        $list = $web.GetList("http://siteName:9090/Style Library/")
        $folderquery =  New-Object Microsoft.SharePoint.SPQuery  
        $foldercamlQuery =  
        '<Where>   <Eq> 
                <FieldRef Name="ContentType" />  <Value Type="text">Folder</Value> 
            </Eq> </Where>' 
        $folderquery.Query = $foldercamlQuery 
        $folders = $list.GetItems($folderquery) 
        foreach($folderItem in $folders) 
            $folder = $folderItem.Folder
            if($folder.ItemCount -gt 0){ 
            Write-Host " find Item count " $folder.ItemCount
                $oldest = $null
                $files = $folder.Files

                $date = (Get-Date).AddDays(-2).ToString(“MM/dd/yyyy”)
                foreach ($file in $files){ 
                    if($file.Item["Modified"]-Ge $date)
                        Write-Host "Last 2 days modified folder name:"   $folder   " File Name: "  $file.Item["Name"]   " Date of midified: "  $file.Item["Modified"] 
                Write-Warning "$folder['Name'] is empty" 

Creating SVG elements dynamically with javascript inside HTML

To facilitate svg editing you can use an intermediate function:

function getNode(n, v) {
  n = document.createElementNS("", n);
  for (var p in v)
    n.setAttributeNS(null, p, v[p]);
  return n

Now you can write:

svg.appendChild( getNode('rect', { width:200, height:20, fill:'#ff0000' }) );

Example (with an improved getNode function allowing camelcase for property with dash, eg strokeWidth > stroke-width):

function getNode(n, v) {_x000D_
  n = document.createElementNS("", n);_x000D_
  for (var p in v)_x000D_
    n.setAttributeNS(null, p.replace(/[A-Z]/g, function(m, p, o, s) { return "-" + m.toLowerCase(); }), v[p]);_x000D_
  return n_x000D_
var svg = getNode("svg");_x000D_
var r = getNode('rect', { x: 10, y: 10, width: 100, height: 20, fill:'#ff00ff' });_x000D_
var r = getNode('rect', { x: 20, y: 40, width: 100, height: 40, rx: 8, ry: 8, fill: 'pink', stroke:'purple', strokeWidth:7 });_x000D_

How to create hyperlink to call phone number on mobile devices?

You can also use callto:########### replacing the email code mail with call, at least according to W3Cschool site but I haven't had an opportunity to test it out.

HTML5 validation when the input type is not "submit"

2019 update: Reporting validation errors is now made easier than a the time of the accepted answer by the use of HTMLFormElement.reportValidity() which not only checks validity like checkValidity() but also reports validation errors to the user.

The HTMLFormElement.reportValidity() method returns true if the element's child controls satisfy their validation constraints. When false is returned, cancelable invalid events are fired for each invalid child and validation problems are reported to the user.

Updated solution snippet:

function submitform() {
  var f = document.getElementsByTagName('form')[0];
  if(f.reportValidity()) {

What's the best mock framework for Java?

The best solution to mocking is to have the machine do all the work with automated specification-based testing. For Java, see ScalaCheck and the Reductio framework included in the Functional Java library. With automated specification-based testing frameworks, you supply a specification of the method under test (a property about it that should be true) and the framework generates tests as well as mock objects, automatically.

For example, the following property tests the Math.sqrt method to see if the square root of any positive number n squared is equal to n.

val propSqrt = forAll { (n: Int) => (n >= 0) ==> scala.Math.sqrt(n*n) == n }

When you call propSqrt.check(), ScalaCheck generates hundreds of integers and checks your property for each, also automatically making sure that the edge cases are covered well.

Even though ScalaCheck is written in Scala, and requires the Scala Compiler, it's easy to test Java code with it. The Reductio framework in Functional Java is a pure Java implementation of the same concepts.

400 BAD request HTTP error code meaning?

Selecting a HTTP response code is quite an easy task and can be described by simple rules. The only tricky part which is often forgotten is paragraph 6.5 from RFC 7231:

Except when responding to a HEAD request, the server SHOULD send a representation containing an explanation of the error situation, and whether it is a temporary or permanent condition.

Rules are as following:

  1. If request was successful, then return 2xx code (3xx for redirect). If there was an internal logic error on a server, then return 5xx. If there is anything wrong in client request, then return 4xx code.
  2. Look through available response code from selected category. If one of them has a name which matches well to your situation, you can use it. Otherwise just fallback to x00 code (200, 400, 500). If you doubt, fallback to x00 code.
  3. Return error description in response body. For 4xx codes it must contain enough information for client developer to understand the reason and fix the client. For 5xx because of security reasons no details must be revealed.
  4. If client needs to distinguish different errors and have different reaction depending on it, define a machine readable and extendible error format and use it everywhere in your API. It is good practice to make that from very beginning.
  5. Keep in mind that client developer may do strange things and try to parse strings which you return as human readable description. And by changing the strings you will break such badly written clients. So always provide machine readable description and try to avoid reporting additional information in text.

So in your case I'd returned 400 error and something like this if "Roman" is obtained from user input and client must have specific reaction:

    "error_type" : "unsupported_resource",
    "error_description" : "\"Roman\" is not supported"

or a more generic error, if such situation is a bad logic error in a client and is not expected, unless developer made something wrong:

    "error_type" : "malformed_json",
    "error_description" : "\"Roman\" is not supported for \"requestedResource\" field"

How do you set the max number of characters for an EditText in Android?


editText.setFilters(new InputFilter[] { new InputFilter.LengthFilter(MAX_NUM) });

Via xml:


Error parsing yaml file: mapping values are not allowed here


  empId: 123
  empName: John
    empDept: IT


    id: 123
    name: John
    dept: IT

For Loop on Lua

names = {'John', 'Joe', 'Steve'}
for names = 1, 3 do
  print (names)
  1. You're deleting your table and replacing it with an int
  2. You aren't pulling a value from the table


names = {'John','Joe','Steve'}
for i = 1,3 do

How to determine the installed webpack version

For those who are using yarn

yarn list webpack will do the trick

$ yarn list webpack
yarn list v0.27.5
+- [email protected]
Done in 1.24s.

Using global variables in a function

You may want to explore the notion of namespaces. In Python, the module is the natural place for global data:

Each module has its own private symbol table, which is used as the global symbol table by all functions defined in the module. Thus, the author of a module can use global variables in the module without worrying about accidental clashes with a user’s global variables. On the other hand, if you know what you are doing you can touch a module’s global variables with the same notation used to refer to its functions, modname.itemname.

A specific use of global-in-a-module is described here - How do I share global variables across modules?, and for completeness the contents are shared here:

The canonical way to share information across modules within a single program is to create a special configuration module (often called config or cfg). Just import the configuration module in all modules of your application; the module then becomes available as a global name. Because there is only one instance of each module, any changes made to the module object get reflected everywhere. For example:


x = 0   # Default value of the 'x' configuration setting


import config
config.x = 1


import config
import mod
print config.x

Oracle SQL update based on subquery between two tables

Without examples of the dataset of staging this is a shot in the dark, but have you tried something like this?

update PRODUCTION p,
       staging s
set =  
    p.count = s.count
where =

This would work assuming the id column matches on both tables.

C# windows application Event: CLR20r3 on application start

I've seen this same problem when my application depended on a referenced assembly that was not present on the deployment machine. I'm not sure what you mean by "referencing DotNetBar out of the install directory" - make sure it's set to CopyLocal=true in your project, or exists at the same full path on both your development and production machine.

Javascript - remove an array item by value

As a variant

delete array[array.indexOf(item)];

If you know nothing about delete operator, DON'T use this.

Combining border-top,border-right,border-left,border-bottom in CSS

No you can't set them as single one for example if you have div{ border-top: 2px solid red; border-right: 2px solid red; border-bottom: 2px solid red; border-left: 2px solid red; } same properties for all fours then you can set them in single line

div{border:2px solid red;}

from unix timestamp to datetime

I would like to add that Using the library momentjs in javascript you can have the whole data information in an object with:

const today = moment(1557697070824.94).toObject();

You should obtain an object with this properties:

today: {
  date: 15,
  hours: 2,
  milliseconds: 207,
  minutes: 31,
  months: 4
  seconds: 22,
  years: 2019

It is very useful when you have to calculate dates.

Android Whatsapp/Chat Examples

If you are looking to create an instant messenger for Android, this code should get you started somewhere.

Excerpt from the source :

This is a simple IM application runs on Android, application makes http request to a server, implemented in php and mysql, to authenticate, to register and to get the other friends' status and data, then it communicates with other applications in other devices by socket interface.

EDIT : Just found this! Maybe it's not related to WhatsApp. But you can use the source to understand how chat applications are programmed.

There is a website called Scringo. These awesome people provide their own SDK which you can integrate in your existing application to exploit cool features like radaring, chatting, feedback, etc. So if you are looking to integrate chat in application, you could just use their SDK. And did I say the best part? It's free!

*UPDATE : * Scringo services will be closed down on 15 February, 2015.

Converting two lists into a matrix

Simple you can try this

a=list(zip(portfolio, index))

Key Value Pair List

Using one of the subsets method in this question

var list = new List<KeyValuePair<string, int>>() { 
    new KeyValuePair<string, int>("A", 1),
    new KeyValuePair<string, int>("B", 0),
    new KeyValuePair<string, int>("C", 0),
    new KeyValuePair<string, int>("D", 2),
    new KeyValuePair<string, int>("E", 8),

int input = 11;
var items = SubSets(list).FirstOrDefault(x => x.Sum(y => y.Value)==input);


a full console application:

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication1
    class Program
        static void Main(string[] args)
            var list = new List<KeyValuePair<string, int>>() { 
                new KeyValuePair<string, int>("A", 1),
                new KeyValuePair<string, int>("B", 2),
                new KeyValuePair<string, int>("C", 3),
                new KeyValuePair<string, int>("D", 4),
                new KeyValuePair<string, int>("E", 5),
                new KeyValuePair<string, int>("F", 6),

            int input = 12;
            var alternatives = list.SubSets().Where(x => x.Sum(y => y.Value) == input);

            foreach (var res in alternatives)
                Console.WriteLine(String.Join(",", res.Select(x => x.Key)));

    public static class Extenions
        public static IEnumerable<IEnumerable<T>> SubSets<T>(this IEnumerable<T> enumerable)
            List<T> list = enumerable.ToList();
            ulong upper = (ulong)1 << list.Count;

            for (ulong i = 0; i < upper; i++)
                List<T> l = new List<T>(list.Count);
                for (int j = 0; j < sizeof(ulong) * 8; j++)
                    if (((ulong)1 << j) >= upper) break;

                    if (((i >> j) & 1) == 1)

                yield return l;

How can I force browsers to print background images in CSS?

Browsers, by default, have their option to print background-colors and images turned off. You can add some lines in CSS to bypass this. Just add:

* {
    -webkit-print-color-adjust: exact !important;   /* Chrome, Safari */
    color-adjust: exact !important;                 /*Firefox*/

Note: It's not working on the entire body but you could speciy it for a inner element or a container div element.

Python error when trying to access list by index - "List indices must be integers, not str"

A list is a chain of spaces that can be indexed by (0, 1, 2 .... etc). So if players was a list, players[0] or players[1] would have worked. If players is a dictionary, players["name"] would have worked.

Getting binary (base64) data from HTML5 Canvas (readAsBinaryString)

The canvas element provides a toDataURL method which returns a data: URL that includes the base64-encoded image data in a given format. For example:

var jpegUrl = canvas.toDataURL("image/jpeg");
var pngUrl = canvas.toDataURL(); // PNG is the default

Although the return value is not just the base64 encoded binary data, it's a simple matter to trim off the scheme and the file type to get just the data you want.

The toDataURL method will fail if the browser thinks you've drawn to the canvas any data that was loaded from a different origin, so this approach will only work if your image files are loaded from the same server as the HTML page whose script is performing this operation.

For more information see the MDN docs on the canvas API, which includes details on toDataURL, and the Wikipedia article on the data: URI scheme, which includes details on the format of the URI you'll receive from this call.

Find Locked Table in SQL Server

You can use sp_lock (and sp_lock2), but in SQL Server 2005 onwards this is being deprecated in favour of querying sys.dm_tran_locks:

    object_name(p.object_id) as TableName, 
    resource_type, resource_description
    sys.dm_tran_locks l
    join sys.partitions p on l.resource_associated_entity_id = p.hobt_id

How to fix Terminal not loading ~/.bashrc on OS X Lion

Terminal opens a login shell. This means, ~/.bash_profile will get executed, ~/.bashrc not.

The solution on most systems is to "require" the ~/.bashrc in the ~/.bash_profile: just put this snippet in your ~/.bash_profile:

[[ -s ~/.bashrc ]] && source ~/.bashrc